People's lives are still greatly impacted by the novel coronavirus outbreak, which has no effective treatment; however, the SARS virus two decades ago quickly disappeared. The study aims to find out how the SARS virus spreads, and also compares the SARS virus to the novel coronavirus. In the whole study, the author used the SIR model and the SEIRP model. It also combines specific cases of specific cities. Finally, through analysis, it is found that the epidemic of COVID-19 can be defeated by mass immunization and improving medical treatment. And how to prevent the spread of novel coronavirus.

The theory of groups exists in many fields of mathematics and has made a great impact on many fields of mathematics. In this article, this paper first introduces the history of group theory and elementary number theory, and then lists the definitions of group, ring, field and the most basic prime and integer and divisor in number theory that need to be used in this article. Then from the definitions, step by step, Euler's theorem, Bézout's lemma, Wilson's theorem and Fermat's Little theorem in elementary number theory are proved by means of definitions of group theory, cyclic groups, and even polynomials over domains. Finally, some concluding remarks are made. Many number theory theorems can be proved directly by the method of group theory without the action of tricks in number theory. Number theory is the thinking of certain special groups (e.g., (Z,+),(Z,×)), so the methods of group theory work well inside number theory.

In recent years, the role of big data technology in various industries has become increasingly prominent. With the rise of the pet trend, the pet medical industry has been developing rapidly. However, the current application of big data in the pet medical industry is single and elementary. This study aims to improve the current situation of big data technology in the pet medical industry and build a pet medical information management system supported by Spark computing framework, HDFS, and HBase. This study uses descriptive research method and comparative analysis method to prove that big data analysis based on Spark framework can greatly improve the efficiency of treatment and reduce the time cost. The information management system based on Spark framework can realize the rapid storage and calculation of massive data, reduce the technical threshold of data application area in pet medical industry, and help to promote the accelerated development of big data industry and pet medical industry.

With economic growth, ship transportation plays a major role in global logistics. The optimization of the ship form based on minimum resistance has been the research focus of ship builders for hundreds of years, but the actual process is quite complex, which also brings huge benefits. Ship drag reduction is not only conducive to industrial economic growth, but also helpful to improve the global energy consumption and environmental problems. In this paper, the Reynolds number and the Froude number are obtained by a dimensional analysis, and then the data are obtained from the model ship experiment with the same Froude number by the law of similarity. The total resistance is subdivided into four kinds with different causes, namely the friction resistance, wave-making resistance, form resistance, and additional resistance. In this way, the ship resistance can be reduced more scientifically and efficiently.

As the world has grown rapidly over the past century, so has the aviation industry as a whole. This has led to a huge volume of aviation market and at the same time the aviation market excessive reliance on fuel, with a consequent huge environmental impact. As a global community, we are moving towards an electrified transport architecture. And some studies of aircraft propulsion systems have shown that electric and hybrid electric propulsion systems offer significant benefits over conventional fuel propulsion systems. However, there are also some researches have shown that while some electrified propulsion strategies can result in significant reductions in CO2 emissions, the overall cost of the aircraft can also increase significantly. The economic efforts made in terms of purely electric and hybrid propulsion have not been significant, so this technology is not yet in significant use in the aviation market. This paper considers some of these systems and analyses their structural advantages, technical requirements, etc. This is followed by a discussion of the current difficulties and future trends in the application of purely electric and hybrid propulsion systems. It is also significant to convey that the current immaturity of this technology and the areas for improvement.

In this day and age, people's lives are inextricably linked to electricity, which is being used more and more in everyday life. The traditional transmission of electrical energy usually uses materials such as metal wires and cables as the transmission medium, and the losses and potential damage (line deterioration, tip discharges) caused by this transmission medium are inevitable. The introduction of radio has been very effective in reducing this situation, and the development of Wireless Power Transfer (WPT) technology has seen three major developments since then, with Tesla lighting a phosphorescent lamp at the Colombian World's Fair in 1893, igniting hopes for WPT. This new way of transmitting electrical energy has expanded the imagination of people in terms of power supply methods by making it possible to provide more freedom in situations where cable charging is not suitable.The working theory, fundamental design, and potential applications of wireless energy transmission technology are covered in this study. By doing this, it offers insight into the development and use of wireless energy transmission technology as it is now. In the end, it is envisaged that the market will adopt wireless energy transfer technology extensively.

At 9:00 Beijing time on October 15, 2003, the Long March II F rocket was successfully launched into space, and the ShenZhou V manned spacecraft carried by it was also China's first manned rocket launched into space. Yang Liwei, the ShenZhou V astronaut, became China's first astronaut , which also showed the great progress of China's space industry. This paper studies the Long March II Series rocket piloted by Yang Liwei, and analyzes the forces on the rockets in the expected state from the aspects of aerodynamics, basic mechanics, and gravity through the Long March II rocket parameters published to the public. The final data shows that air resistance and gravity will cause a great consumption of the rocket fuel.

A constructive Function is a computer program that transforms a Constructive Real Number (CRN) into another CRN. A left number is a program that generates an increasing sequence of rational numbers with an upper bound. We use algorithmic functions to generate CRNs and Left numbers. In this essay, we will prove the continuity of such functions on Left numbers in topological space with the base of right rays.

With the continuous improvement of science and technology, optimization has become an indispensable and important part of people's lives. Optimization problems also help people find the optimal solution in their lives. It is necessary to mention the practical application of optimization problems in reality. The purpose of the experiment in this paper is mainly to find out whether the optimization problem is far away from people through practical application examples, or whether it is closely related, and to explore whether it helps people's lives. This experiment is a verification of this problem. This experiment mainly uses Python and the gradient descent method to prove the practicality and efficiency of optimization problems. Specifically, it is based on the background of buying a house. The data comes mainly from practical examples of Guangdong, Baoan. The results are also obvious, successfully demonstrating that the practical application of optimization problems can improve people's lives, improve efficiency, and are closely related to people's lives.

Over 1.6 percent of senior citizens who are 65 years or older in the United States have Parkinson's disease, which leads to economic, psychological, and physical problems for the patient and their families. Parkinson's disease patients usually have tremors in their hands, which takes away their ability to eat independently. According to research, the main food source for seniors is liquid food, since it is easier to digest. To solve this, this research created a prototype of an inexpensive liquid feeding machine for Parkinson's patients that is easy to use and install. This study used 3D-printed parts, laser-cut parts, and off-the-shelf parts. The feeding machine can replace the job of a caretaker so that seniors will be able to eat independently.

Mobile games have become a popular form of leisure and entertainment around the world. China's economy is growing as mobile games take a larger share of the country's mobile gaming landscape. Many people's efforts have gone to waste as online scammers steal their game accounts, private information, and virtual property. There are many problems in network security, such as increasing trust in fraudulent accounts; posing as an active party to swindle player information, transmission of Trojan viruses. Therefore, this paper puts forward countermeasures to these network security problems, summarizes the application of encryption technology and identity authentication technology in the transmission of personal privacy information, and proposes the use of part of the RSA encryption algorithm. So as far as it is possible to reduce the network game security problems and improve the network anti-theft system defense ability.

In 2020, Airbus tested an plane called "albatross", which is a small version of Airbus A321. It is made of carbon composite and glass fiber reinforced resin and has been continuously developed in Felton, South Gloucestershire, England for more than 20 months. This paper describes various plane designs using variable technology, and introduces the albatross as an example. And the nonlinear dynamic characteristics and aerodynamic interference caused by the deformed parts will be discussed. Finally, the general and special challenges of these problems to civil plane operation are summarized. The research results of this paper can provide theoretical reference for the design of deformable civil plane in the future.

As a drawback to the widely accepted standard Big Bang model, the Flatness problem has been highly controversial. Due to the presence of dark matter and difficulty in measuring distances between galaxies, the universe's density in the present day has high uncertainty. There are three models consistent with the cosmological principle. The Flatness problem originated from the uncertainty of the density parameter and the puzzling fine-tuning of omega and the point of the Big Bang; its potential to identify a shortcoming in the standard cosmological model has drawn considerable attention from the scientific community. Different approaches were taken as attempts to resolve this problem. However, arguments against the Flatness problem have also been proposed, disproving the existence of the Flatness problem from the perspective of classical cosmology. This paper examines the Flatness problem by quantitatively describing the flatness problem, presenting the historical development of the Flatness problem, analyzing past approaches to the Flatness problem, and considering arguments against the problem from the perspective of classical cosmology.

Glauber Monte Carlo model is frequently used in analyzing high-energy heavy ion collisions. This paper focused on implementing the Glauber model in the simulation of two 208Pb particle collisions and furthered the computation of the basic structure of heavy ion collisions. Not only did this research give a method to calculate the impact parameter and number of participating nucleons, but it also discussed the calculation of participant eccentricity and triangularity. Description of assumptions that goes into the computation are included, and a comparison of theoretical result and estimation are delivered.

The work briefly summarizes the Standard Big Bang Model, with some new frontier works demonstrating a more realistic Big Bang scenario. The main contributions are from the development of String Theory and Cosmology. The deduction and establishment of the Big Bang Theory undergo continuous contributions, from the microwave background radiation and the observation of Hubble's constant, the first impression resulting in the basic structure of the theory, to the later works, such as Friedman's equation, which introduced the theory to be rational. While there are still many details waiting to be fully understood, in this summary, we review the extensive bang process from the perspective of frontier research in string theory, both singular and non-singular models, and the related scenarios derived from the standard model of the big bang theory. We also examine the evidence supporting the model and the pre-big bang cosmology and provide a brief overview of the universe's fate based on the trend of Hubble's constant about string theory. The scenarios under different evolutive trends of Hubble's constant, related briefly to the string theory, were roughly calculated and proved to demonstrate the final state, or the universe's fate, where there is evidence for an always-existing universe. We also demonstrate the possible scenario of a cyclic model, which may be an alternative model for the real sense of the universe's evolution.

The study of the properties of analytical functions is described as complex analysis. The residue theorem is an important conclusion in complex analysis. This paper introduces the origin of imaginary numbers from Cardano Formula defines the conversion of complex number formats from the Euler Theorem, and proves the intermediate theorem Cauchy Integral Formula before reaching our final conclusion and the goal of the paper, Residue Theorem. The name of the theorem comes from the concept of residue, which is defined using a function’s Laurent series. We could then derive the Residue Theorem from the Cauchy Integral Theorem, also called the Cauchy-Goursat Theorem. We will be able to formalize our prior, ad hoc method of computing integrals over contours encompassing singularities. Additionally, it is a theorem that may be applied to zero-pole qualities and curved integral properties. The Residue Theorem is the basis of many essential mathematical facts revolving around line integrals, particularly in solving ODEs and PDEs and describing physics models.

Dark matter is counted as two of the significant discovery and research topics in the academic and scientific fields. Found later that dark matter does not belong to any of the present areas of known matter, dark matter was discovered in the late 19th century and early 20th century by indirect measuring of the abnormal velocity and mass dispersion pattern detected by multiple astronomers and mathematicians. In the last several decades, scientists from different physics fields have determined the property, location, potential candidate, origin, and interaction of dark matter. Starting with the history of the discovery and research of the dark matter, the dark matter property will be illustrated in the abstract. One of the properties of dark matter is the property that dark matter does not absorb, reflect or interact with any photons and any kinds of electromagnetic waves. The two potential dark matter candidates are WIMP (weakly interacting massive particle) and axion. The reason the scientist suspected that the two particles are the candidate for dark matter is also listed. Experiments about the candidates and other observations and theories are also listed in the paper.

Since winglet be added on the motorcycle in 2016 first, the extreme speed of the motorcycle competition improve a lot. The engineers of motorcades not only focus on the efficiency of the engine, but also put some of their attention on the design of the aerodynamic kits. This paper is focus on the shape of the racing track to see how it effect the choosing of winglet. Since different surface area of winglet may have some effect on the force provided on the motorcycle. This paper finds that for the racing track which has more strait roads, the motorcycle should reduce the drag force, so that the winglet should has less surface area, vice versa. The research significance is to help motorcades to choose suitable aerodynamic rate and give some suggestion to the rider who want to add winglet on their own motorcycle.

This paper presents an analysis on a parametrization of ALICE open data on the Pb-Pb collisions at √sNN = 2.76TeV created by the Large Hadron Collider (LHC). We will use the tracklet method to calculate the differences in pseudorapidity values (∆η), generate ∆η distributions for different centrality ranges, and investigate the centrality dependence of the number of particles produced. This document presents findings of a negative correlation between centrality classes and the number of particles produced.

The transformation of the sun, the moon, and the stars, the visible but unreachable universe, has made generations of people fascinated by it. The rapid development of science and technology is the cornerstone of human exploration of space, and spacecraft is an indispensable and essential part of human space exploration. This paper introduces the development process of spacecraft from 1960 to the 21st century using literature collection, data integration, and other methods, focusing on the evolution of spacecraft power sources, supplemented by the evolution of spacecraft structure. According to the research results, it is concluded that the power source of the spacecraft shows a development trend from relatively low energy and efficiency to relatively high efficiency, and the structure of the spacecraft is in a development state from only supporting spacecraft exploration to realizing manned navigation.

The upper atmosphere has drawn increasing attention as remote sensing technology has advanced. People start looking into how radiation in the high atmosphere spreads and what materials exist. This paper mainly introduces the radiation of the upper atmosphere from three aspects: the properties of the upper atmosphere, the actual contents of radiation, and the factors affecting radiation. These three aspects explain several extraordinary natural phenomena, such as auroras and magnetic storms. In-depth explanations are provided for the three atmospheric qualities, the particle motion law, and the interference of natural and human forces with radiation. The gas transport theory introduces the interaction of particles in the atmosphere while providing a complete analysis of electronic communication's fundamental operating principle and propagation mechanism. This article finally analyzed the nature of the upper atmosphere and the various kinds of radiation in the upper atmosphere, including what the radiation particles are, as well as the interactions and applications of these particles. This article's main contribution is bringing together a large amount of data about irradiation in the upper atmosphere. Through the collation of this article, later, people can study the content of this piece more easily.

There are different approaches to reduce the drag on a car in motion, and at the same time, the resistance of the car is affected by many factors. This paper focuses on reducing the resistance of the car from three aspects, namely the weight, the windward area, and the aerodynamics, so as to improve the acceleration and speed of the car. This paper also introduces specific optimization models and sketches through data comparison and calculation. It is reflected that the improved vehicle structure can better reduce the drag, thus achieving the purpose of increasing the speed.

Nowadays, China is experiencing extreme heat wave weather this year. Currently, domestic citizens are suffering from the excessive hot weather and have no idea how to protect themselves efficiently from getting illness or having heat stroke. Therefore, we have a research on temperature change rules in some major cities (Shanghai, Guangzhou and Beijing) in China from 2015 to 2020. We collect and obverse several temperature data of Beijing, Shanghai and Guangzhou to see if there are upward or downward trends in temperature. We attempt to understand how temperatures have changed over time in these cities in China and how these trends can help forecast future temperatures. This research can help people know the probable temperature changing trends in the three cities in the next few years and take some precautions in advance.

The search engine (SE) is a senseless artificial program. SE matches the user's information demands with the input information and then provides an ordered list of answers. However, the outputs are frequently subjected to bias, which can affect the depiction of issues like gender inequality. Studies have shown that search engines may unconsciously inherit biases from their creators and users throughout their life cycle. In this paper, focused on Google as our research case, we evaluate and summarize different factors that can lead to the bias issue. The factors are depicted in computer science social domains. And in response to these causes, we propose a workshop idea to raise awareness of the problem of search engine discrimination, especially regarding gender issues. Based on our current workshop solution, we also list some potential improvements.

Automated blind guidance has been a hot research topic, which aims to develop efficient and inexpensive technologies to help blind people meet their daily needs. Benefiting from the rapid development of deep learning and machine vision, artificial intelligence-based blind guidance technology, especially blind guidance technology based on simultaneous localization and mapping (SLAM), has become a promising alternative. In this paper, we introduce the relevant research results of YOLO-SLAM technology in the guidance of blindness. We began by highlighting the power of YOLO, SLAM technology, and the promising prospects for current research in this field. In order to ensure that the information has a higher reference value, we focus on the practical application and improvement optimization of related papers in the past four years. We analyzed existing surveys and looked at current work, using several dimensions such as the data obtained, the sensors used, the models learned, and the human-machine interface. We compared the different methods, evaluated their testing sessions, summarized their similarities and differences, and drew conclusions by analyzing future trends in the field.

Intubation is an emergency medical procedure used to rescue people who are unconscious or unable to breathe on their own. In the process of tracheal intubation, traditional intubation is difficult due to narrow viewing angle, trachea bending, and occlusion of internal structures. Thanks to the rapid development of simultaneous localization and mapping (SLAM) and virtual reality (AR) technologies, intubation aids are also developing towards intelligence and automation. Based on the collection and analysis of a large number of literatures, this paper conducts an in-depth study of the existing SLAM-based intubation-assisted technology. Specifically, on the basis of analyzing the current research on the application of equipment, visualization schemes, and algorithm schemes in tracheal intubation and intubation training, this paper studies the application progress in terms of efficiency, versatility, accuracy, and user feedback. Further, we summarize the existing key issues and discuss future developments.

According to current astronomical developments, Doppler and lensing methods are the two most important methods used by astronomers to detect extrasolar planetary systems. Unlike the lensing method, which requires the use of high-precision astronomical telescopes to measure stellar luminosity variations, the Doppler method can rely on simple stellar redshift phenomena and calculations to accurately predict the existence of extraterrestrial planets, their masses, orbital radii, and other basic characteristics. Therefore, Doppler's method will be the most widely used method to measure planetary systems. Based on the derivation of Kepler's third law, the formulas for calculating the masses and orbital distances of planets are discussed and a python program for easy calculation is presented. Also, the limitations of Doppler's method and possible calculation errors are collected, organized, and explained.

Deep learning is a key technological tool in the field of image identification with wide application prospects because of its significant benefits in feature extraction and model fitting. Deep learning entails numerous stages of non-linear transformations. The primary implementation of the current deep learning technique is the deep neural network, the connection pattern of which takes its reference from the way that the visual cortex of animals is organized. Among all the deep learning methods, Convolutional Neural Network (CNN) is one of the most renowned means to process image. It has excellent performance in terms of large-scale image processing. A convolutional neural network consists of convolutional layers, a fully connected layer, a pooling layer, and associated weights. Convolutional neural networks have fewer parameters to consider than other deep, feed forward neural networks, making them an attractive deep learning architecture. There are several traits in CNN, including pooling, shared weights, and local connections. With the help of these features, the network's complexity and the quantity of training parameters can be decreased, and the model's level of invariance to scale, shift, and distortion can be increased, along with its robustness and fault tolerance. This paper firstly summarized the history of convolutional neural network, then briefly discussed the components like the neuron and multilayer perception. The main structure of the CNN is showed afterwards. The paper also mentioned the features and the applications of CNN, mainly in the field of Computer Vision (CV).

COVID-19 has been the most serious public health problem of the past decade. To date, the pandemic has taken a huge toll on the globe in terms of human lives lost, economic impact and increased poverty. However, due to its viral characteristics, determining whether a patient carries COVID-19 is not easy. RT-PCR methods are the gold standard for detecting COVID-19, but their time cost, as well as the need for specific equipment and instrumentation, limit their ubiquity in some medically underdeveloped areas. Chest X-rays, a test with high ubiquity and rapid results, require a certain number of professionals to read and determine whether a patient is likely to have COVID-19. Therefore, it is important to have a system to assist in the determination in areas where professionals are lacking. In this experiment, a convolutional neural network-based machine learning technique was used to create a model for recognizing COVID-19. Although there is no clinical evidence to prove its effectiveness, the model can assist professionals in judgment to a certain extent.

Today, probability theory is becoming more and more useful in our daily life, and it is used more often in sports, especially in table tennis. As a well-known table tennis player from China, Ma Long is an experienced player in table tennis. The data from this study is mainly from @tingwalker who was famous for statistical table tennis data. This paper uses the probability theory to find the effects of the win rate of Ma Long as well as calculate the actual rate, including the effects we have to consider. It is more accurate than just considering the win rate of each competition or looking at the total winning rate of Ma Long. With the help of probability theory, the paper considers factors that affect Malone's winning rate, such as competition system, different players, independent events, and miss rate. Finally, it can be concluded that Ma Long's winning rate against Zhang Jike is as high as 78%~82%.

In this project, we decided to collect and analyze the data about this cluster from several perspectives. Due to the consideration of distance, we used python to simulate their motion trajectory and position and choose Gaia data release as our data source. Hence, we listed four diagrams out of those data. By analyzing these graphs, we can get some information, such as the distance between M13 and earth and the age of those stars.

The scramjet is the representative of the future jet engine, and it has irreplaceable advantages in terms of working performance and service life. Although it has been developed more than fifty years, there are many problems in the driven system of the scramjet engine. This paper mainly focuses on the problems of the effective thrust and the combustion stability. The research shows that how the pressure ratio affects the positive thrust and the combustion stability. Furthermore, this paper also shows that the elements which can affect the pressure ratio. The lower inlet air temperature is beneficial to enhance the thrust. According to the relevant research which apply the CJ detonation theorem to find the possible reason for the combustion instability. For the possible improvements, the research found that the engine thrust at different speed and the allowable maximum speed. The type of fuel and the reactivity of the fuel can influence the thrust.

In this world of information explosion, people require more effective ways to filter useful information from millions of data. Email as one of the most frequently used form of communication, carries important messages, yet along with messages of fake news, misinformation and scams known as spam emails. Manually categorizing them from non-spam emails requires a lot of time and money and other human along with material resources. In order to deal with this, deep learning, or natural language processing models in particular, is introduced to categorize emails faster and cheaper. The Natural Language Processing model used here is called Bidirectional Encoder Representations from Transformers (BERT). Since BERT is already a pre-trained model, the main task is to do the Fine-Tune part on it, with a dataset that contains around 5000 emails (85% spam emails and 15% non-spam ones). After that the model is tested on a group of 5 emails including 3 commercials/spams and 2 non-spam emails. The result shows that this model could separate them by giving commercials scores closer to 1 (spread from 0.5 to 0.7) and non-spam emails scores close to 1(spread from 0 to 0.1). Therefore, it can be concluded that this model works on small sets of data.

Petroleum is mainly used in the transportation industry and it is now becoming rarer in the world. Petroleum Geologists and analysts have predicted an imminent global peak of petroleum consumption, at which the maximum rate of petroleum extraction will be reached, and then followed by an irreversible decline. To date, 50 countries have passed the point of no return. Therefore, there is no time to delay the saving of petroleum. Since petroleum is mostly used by various means of transport, vehicles that are more efficient with less use of petroleum are needed. Under this context, this paper introduces three types of vehicles making full use of energy. Through case studies, the development tendency of future vehicles is illustrated, and a conclusion can be drawn that clean energy hybrids and hydrogen-powered fuels have become a future development trend for vehicles.

After a period of scientific research practice, the author has acquired some relevant knowledge, and it is hoped to have the Milky Way rotation curve of the gradual improvement process presented. The author uses the literature method to summarize the history of the study of the galactic curve, and show the process in the relative descriptive discourse.

This project studies and analyzes depression through statistical principles, reveals the influence and behavior of depression, so as to improve people's attention to depression. This study was completed from: looking for basic information data sets of depression, reading data sets, making charts, analyzing data and data prediction. The results showed that the affected population was concentrated between young people and middle-aged people, and the influencing factors of the disease included marriage, gender, employment and so on. For this disease, research is still in the development stage and there are still many questions to be addressed, so it is very important to study this disease.

Generative Adversarial Networks (GANs) is becoming more and more popular, artists use them to find their own inspirations, computer scientists use it for data synthesis, workers use it for machine fault diagnosis and so on. However, GANs are flawed despite its popularity: they are unstable. GANs are based on game theory. In a typical GAN model, the generator and the discriminator are both improved by competing with each other. Therefore, in this highly competitive training process, GANs can easily run into trouble while they move towards the optimal solution. In most cases, the case of such instability arises from the loss function, or in other words, the gradient of the loss function. This research proposed a new set of GAN that replaces its objective function with supcon, or the supervised contrastive loss to solve gradient-related problems. We have also proved that under our model, the GANs are less likely to suffer from these two factors of instability. Finally, we have compared our model and the traditional generative adversarial nets.

To mitigate or avoid losses caused by earthquakes, it is necessary to understand them deeply. In our project, two idealized second-story structures with different properties with multi-degree of freedom-free vibration will be analyzed. The displacement response of the first structure is analyzed under the conditions with and without an available load by the modal superposition method. As a result, the properties, including the natural frequencies, mode shapes, and the second-floor story shears, have also been obtained. Moreover, the same properties of the second structure are obtained, too, except for the story shear. Moreover, the displacement response of each phase of the impulsive loading of the second structure is also computed by using Duhamel Integral.

The passage mainly discusses the solution to overfitting. Overfitting usually happens when people are training their machine learning models. When a model is overfitted, it only fits one particular dataset and misses most of the data points from another dataset. This problem affects the model's performance and makes it unable to use for its purpose. So how to solve this problem with significance and practical meaning? At the beginning of the passage, I will introduce some theoretical foundations for overfitting. Then I will define the concept of overfitting and show an example of overfitting in the machine learning model. After that, I will tell you how to pick the correct model with the testing set. Then, the passage focuses on the discussion of regularization, which is a helpful technique for solving overfitting. And I will compare the L1 and l2 regularization to help you find the suitable one.

As the global climate starts to change due the exploitation of natural resources by human, internal combustion engines are no longer the favorite son of mankind. Instead, alternatives such as hybrid power systems and electric motors have drawn the attention of various car manufacturers and numerous scholars from worldwide. At the same time, the automobile industry has not given up internal combustion engines yet, and kept producing innovative engine designs aiming to minimize the negative impact of fossil-fuels on the environment. By researching, analyzing, and comparing data and information from various sources, this article will discuss the fundamentals and working basics of internal combustion engines, hybrid power systems and electric motors, the iconic innovations on internal combustion engines by several car manufacturers, and will compare traditional engines and its alternatives through various aspects. This essay will mainly focus on internal combustion engines and some of the more environmentally friendly alternatives available today, as well as a comparison between them and their advantages and disadvantages.

Dark matter has been proposed to fulfill the missing mass from Astro-observation. Many theories have been raised to explain dark matter, and weakly interacting massive particles (WIMPs) are one of them. In recent decades, dark matter detection sensitivity has improved significantly. However, solid evidence for their existence has not come yet. This paper outlines some methods for detecting dark matter, including direct detections, collider searches with the ATLAS detector at LHC, and collider searches with CEPC.

This paper expounds the basic concept of group theory and its application in Rubik’s Cube transformation and restoration formula. The different states of the magic cube are regarded as the elements of the magic cube group, and the set generated by six basic operations is equivalent to the homomorphism of the magic cube group for analysis, from the mathematical characteristics of the permutation group to some practical examples. The collection of possible states of Rubik's Cube is a group, called Rubik's Cube Group, which can be analyzed with the knowledge of group theory. The essence of the magic cube group is the subgroup of the substitution group. There are six basic operations of the magic cube. The combination of basic operations can only produce even pairs of blocks to exchange positions or flip directions at the same time. Therefore, there are some restrictions on the transformation of the magic cube. Some practical examples give some ideas for creating the magic cube formula.

The simple pendulum is a typical model of the compound pendulum. In this model, resistance and buoyancy are negligible. This paper researches how air resistance affects the vibration period in the simple pendulum model but with exact conditions. There are two simplified air resistance models that can apply in the models, one is the first power air resistance model, and the second is the second power air resistance model. But the first power air resistance model is quite complex, there is no equipment to measure its coefficient of it, so it only applies the second power air resistance. This paper studies the formula that revealed air resistance and related suitable cases. The results show that the time from the formula is longer than the experiment a little bit.

This paper mainly demonstrates the development history, types and structure composition, measurement and control technology, development requirements and prospects of aeroengines. As the "flower of industry", aeroengine is an extremely important scientific and technological product in the new era. At present, in China, the measurement and control technology has achieved a great breakthrough, but still needs to be improved. It has obtained the view that there is much room for improvement in big data, energy conservation and environmental protection, materials and efficiency in the future, and the application of variable mode aeroengine, wear-resistant coating, intelligent manufacturing technology and hydrogen fuel is also a possible development direction

Whether an item is popular or not depends largely on its cost performance. For manufacturers, it is very important to create the most high-quality items with the least amount of money. For example, in the case of the same material, what kind of bridge structure is the most material-saving and long-life, what specific design can make the car more fuel-efficient and faster, and what kind of special pipeline design can make the flow of water resources more efficient are problems that manufacturers need to constantly explore, and fluid mechanics can help and solve these problems to a large extent. This paper mainly introduces the application of fluid mechanics in bridge engineering, automobile design, and agricultural production. The author analyzes the working principle of fluid mechanics, including some speculations on the future development direction of fluid mechanics.

Aeroplane-One of the greatest inventions of the twentieth century. Since ancient times, man has dreamed of flying in the sky like a bird. In modern society, due to the rapid development of science and technology (fluid mechanics, automatic control system, etc.), aircraft has become a basic means of transportation. This paper mainly studies how the aircraft takes off and the role of its individual components. Through the method of literature reading and analysis, the force of aircraft takeoff, as well as the role of wings and flaps (Kruger flaps, slit flaps, fuller flaps) in the take-off process are summarized.According to Bernoulli's principle, the lift of an aircraft is mainly generated by the wings, and parts such as flaps are used to regulate the flight state of the aircraft. At the same time, the aircraft must overcome a variety of drags during flight, including frictional resistance, tip resistance and induced resistance.

Because of the rapid development of social economy and urbanization, people's quality of life has been significantly improved, while people's requirements for housing construction. The requirements of space and environment are also increasing. To effectively meet people's needs, it is necessary to dig deeper into the functions of buildings, increase innovation, promote the integration of architecture and structure, and increase the development growth and to contribute a high level of construction building design. This paper discusses the application of structural design innovation in architectural design, discusses architectural structure design principles, and discusses design innovation countermeasures from the level of integration of architecture and structure in order to promote the further development of the construction industry.

An aerosol is a system of liquid or solid particles in suspension in a gas, which includes both the particles and the suspended gas. The aim of this paper is to study the thermophoretic forces in aerosol systems. We introduce the concepts of particle size distribution, DLVO theory and multiphase flow models, followed by four case studies of thermophoretic deposition. This study has some limitations that need further investigation for a number of specific reasons. Firstly, the impact of thermophoresis is often overlooked in discussions about aerosols and their walls. Additionally, the focus has only been on solid walls, while the same problem applies to soft walls such as the human respiratory tract. The complexity of fluid models that involve multiple particles and forces also presents challenges. The task of examining the effects of temperature fields and temperature variations will be even more daunting. There is a pressing need for further research in this area.

Wireless power transfer (WPT) is one of the most frequently discussed topics. Due to its straightforward implementations and designs, it is also one of the most commercialized. It is a technology that allows power to be transferred from one electrical transmitter to another electrical transmitter across an air gap. Inductive coupling, magnetic resonance coupling, and radio-frequency transfer are the three widely used wireless power transfer technologies, and this study provides a thorough summary of their respective histories. Latest implementations are also introduced. Current implementation of the technology in vogue are confronted with some challenges, which may be seen as future research trends, in hope of miniaturizing gadget complexity, enhancing device transmission duration and reducing costs.

To solve the problems of not being easy to bring the traditional fan and the weak wind, the single function of the portable, and other limitations, this paper studies the improvement of a kind of multifunctional portable fan. The multifunctional portable fan achieves its purpose of portability. It must have a small size and battery. A modular design is adopted in this paper to solve these problems. After designing the plan. This paper tested the shell's various functions, which were created using 3D printing technology. The test results show that the design can effectively play to the versatility of the fan. A modular design will enable tools to be extensible. It reduces the cost of using tools and the waste of resources.

AADRES has been further optimized over the past hundred years for diminishing fuel consumption, yet there is still a sharp reduction in traditional energy around the world. Recently, the energy structure of automobiles has also been transforming from gasoline power to electric power in order to save energy and reduce the CO2. However, electric cars have one fatal problem which is battery capacity. Therefore, AADRES should be redesigned for electric cars. In order to find an AADRES suitable for electric cars, this paper briefly explains the resistance principle of cars and instances some existing aerodynamic drag reduction methods. By analyzing and identifying those methods, a personal scheme of new style AADRES for electric cars is also presented, which primarily follows the wedge car shape but incorporates a deflector, embedded door handle, and pitted non-smooth surface while removing door mirrors.

Most map applications play the job of navigating users and informing them of traffic jams. However, they often cannot deal with an emergent situation when a disaster such as a flood takes place. This paper aims at providing a solution for map and navigation applications how to ensure users’ safety when natural disasters of floods happen. The subject uses sensors, programming, and perceptrons to prompt the study and take the Beijing-Hangzhou canal as a sample since each river has its warning water levels. Nevertheless, this paper provides a solution to the research aim, no experiments are involved.

We discussed possible improvement methods for a dual-species atom interferometry test of the weak equivalence principle (WEP) at the 10^(-12) level. The original research tested the WEP by comparing the acceleration difference of the free-fallen rubidium isotopes atom clouds. Based on the percent uncertainty presented from this test, AC stark shift is the most significant obstacle to improving precision. This article will discuss a precision-improving method to the original test by suppressing the background AC stark shift by centering the interferometry lasers to their "magic frequency." The expected improved precision of the uncertainty level is below the 10^(-18) level. Due to the limitation of instruments, we have yet to test this improving method in the actual measurement. Still, we analyzed the possible difficulties in practical usage and discussed solving strategies that correspond to the problems.

Gliders are heavier-than-air fixed-wing aircraft that do not rely on power plants to fly, and are now widely used in scientific observation, daily entertainment, and other fields. After taking off, it only relies on the reaction force of air acting on its lifting surface for free flight. Different gliders can stay in the air for different amounts of time in different environments, which is mainly determined by the airfoil. Therefore, through literature reading, this paper understands its flight principle, and studies and analyzes the advantages and disadvantages of existing airfoils by comparing the influence of different airfoils on flight performance. In view of the problems existing in the airfoil, rationality calculations and improvements are put forward, hoping to promote the development of the aviation industry. After research, the concave wing is by far the most suitable gliding airfoil, which can provide relatively large lift and stability, but there is still the problem of insufficient load. In order to improve these deficiencies, the airfoil is optimized by increasing the contact area between the airflow and the wing. For example, the defect can be improved by lengthening the length of the entire wing, reducing lateral airflow, and increasing the upward curvature of the wingtip.

Numerous civil infrastructures, such as bridges, dams, and skyscrapers are getting to be vulnerable to losing their planned capacities as they break down from utilization. In spite of the fact that many people have been propelled to examine these structures by the concern on a regular basis, there is still diagnosis in need for onsite inspections on closing bridge frameworks or building structures for diagnosis, due to lack of personnel. In that case, many researches team have come up with structural health monitoring (SHM) techniques. This paper will investigate a few strategies for SHM techniques. The scope is primarily on machine learning strategies, such as vision-based strategy for SHM techniques. Based on other correlated articles, vision-based strategy is fine to be used for structural health monitoring and detection. Models that are well defined will be applied to different kinds of issue. There's much to think about and research here. To summarize, machine learning techniques for SHM have been shown to be more successful than traditional strategies. The primary paper employments territorially upgraded multiphase division procedure, which is prepared with SVM, which has been shown to be superior to previous methods. Overall, ML methods are gradually becoming crucial perspectives on SHM challenges.

Quantum computing is the engineering of utilizing the properties of a quantum, as so could be understood as the using the rules of nature at the scale of an atom, to calculate faster and more complicated problems than traditional computers. These new inventions are not merely a device that calculates faster than the speed convention computers, the only similarity between them might only be some essential hardware and their names, because unlike conventional computers that uses classical physics to transmit electronic information, quantum computers utilize quantum physics to perform calculations. Quantum computing has the potential to replace conventional computers in solving important problems in fields such as chemistry, cryptography, materials science, medicine, and artificial intelligence, which are all task that are uneasy and sometimes devastating for conventional computers to do. Quantum computers’ characteristics includes but are not limited to: stronger information processing abilities and a faster calculation speed. Compared with traditional computers, the greater the amount of information it processes, the better a quantum computer can calculate a more accurate result. This paper is focused on researching and explaing the characteristics of quantum computers and their possible contributions to the human society.

Dust is a ubiquitous feature of the cosmos, impinging directly or indirectly on most fields of modern astronomy. Dust grains composed of small (submicron-sized) solid particles pervade interstellar space in the Milky Way and other galaxies: they occur in a wide variety of astrophysical environments, ranging from comets to giant molecular clouds, from circum-stellar shells to galactic nuclei. The study of this phenomenon is a highly active and topical area of current research. Dust absorbs optical and Ultraviolet (UV) photons and re-emit them in the infrared. The heating and cooling of dust interact with their environment closely. Dust is closely related to the star formation process, and study on dust could put constraints on the star formation history. While extensively studied in the optical, the extinction property of dust in the UV is still an open question. UV photos are absorbed by earth atmosphere and cannot be accessed from ground-based observations. NASA space mission Galaxy Evolution Explorer (GALEX), on the other hand, provides critical data to this question by surveying the whole sky in two UV bands. By comparing the optical and UV properties of blue and red (dust-absorbed) quasars selected from Sloan Digital Sky Survey (SDSS), we shape the extreme UV dust extinction curve for the first time. The measured UV dust extinction curve will help us characterize the size distribution of dust grains and their compositions which could not be easily accessed by other methods.

The idea of the study was mainly from the concerns about whether wheels of different shapes can also fit well in cars. This paper mainly involves the demonstration of some theoretical features of the Reuleaux triangle and some practical situations of using the triangle as wheels. The aim of the study is to find out some basic features and mathematical rules of the Reuleaux triangle, in addition, the practical uses of this shape will also be studied. In order to learn expertise about this triangle, the author went through papers about geometry and some demonstrations by different mathematicians from different times. The author then made a few assumptions and tried to prove himself to find the rules of this shape more deeply. In conclusion, it found out that the Reuleaux triangle is actually a perfect constant width curve and it can be used as wheels under proper conditions. Apart from that, this paper also concluded an exact method of drawing different constant width curves.

It is known well that electricity is an important part of our life and most of it is wasted. However, the natural resources of energy are being wasted and reduced. To utilize the mechanical energy of rotating wheels, in this research report, the device structure of generating electricity voltage is designed, and the relations between the voltage generated by rotating wheels and the geometry and physical parameters of the structures are derived, and the effects of the geometry and physical parameters on the voltage are analyzed. The theoretical results show that the voltages are in proportion to the weight and speed of rotating wheels. The experiments with piezoelectric film and wheels are used to verify the theoretical analysis. The experimental results show that the theoretical analysis is in good agreement with measured results.

In this era, molecular dynamics and Monte Carlo methods have become the primary simulation methods. With the emergence of computer simulation research methods, it has been possible to solve the sizeable computational volume and some other problems in the simulation process. At present, molecular dynamics simulations have taken an essential place in the substantial computational system and have a remarkable ability to solve multi-body problems. Therefore, researchers widely use it in many fields such as physics, chemistry, and materials science. Meanwhile, the Monte Carlo method is also a very effective statistical simulation method. This method can far surpass ordinary integration in efficiency with guaranteed computational accuracy. Furthermore, the derived kinetic Monte Carlo method can simulate and study dynamics problems. It can be seen that both simulation methods play an vital role in various disciplines. Therefore, it is very significant to understand the mathematical principles behind them and to know their advantages and disadvantages.

At the end of the 19th century, with the development of Newton's classical mechanics and Maxwell's electromagnetism, a great number of individuals believed that the laws of physics had reached the point of perfection. Physicists like Pierre-Simon Laplace even thought that Newtonian mechanics could be used to calculate the future. However, the "dark clouds" such as the Michelson-Morley experiment and black body radiation demonstrated the flaws of the classical theory. With the efforts of quantum mechanics pioneers such as Planck, Einstein, Schrodinger, and Heisenberg, the discipline of quantum mechanics has gradually developed and has become the key to opening the door to the microscopic world. This paper demonstrates the cracks that occurred in classical physics at the end of the 19th century, and then illustrates the birth of the quantum mechanics and some of the most important concepts of it. Finally, some cutting-edge technologies related to quantum are introduced.

With the increase in the demand of space exploration in recent years and the increase in the amount of communication data between the earth and spacecrafts, the development of deep space communication is undoubtedly a great support for space exploration. Deep Space Network (DSN) is an important organization that helps people to get in touch with spacecrafts. This paper introduces the communication technology and achievements of the DSN and the problems that are still facing by it, and look forward to the future development trend of deep space communication and exploration technologies, so as to promote the development of Deep Space Network.

Despite the vast research on spinning black holes and jets, little is known about details of jet formation. This paper is aimed to study whether Penrose’s prediction that black hole spin power jets can be verified. Once proved, a deeper understanding of energy/momentum transfer near event horizon is to be achieved. This paper compares two dominant spin measuring methods. Thermal continuum fitting method makes use of thermal emission to measure the spin, where a theoretical flux profile is created by inputting parameters (inclination of X-ray binaries, distance of X-ray binaries from the earth, mass of black hole, etc). X-ray reflection method uses broadened Fe-line to measure the spin, and that corona geometry is often required. This paper also compares various definitions of jet power and spin-jets relation. In conclusion, transient jets are highly possible to be powered by black hole spin, but more evidence is required to confirm this. Steady jets remain in a vague relation with spin. It has also been found that different measuring methods of both spin and jets can affect the spin-jets relation.

In the field of air control, fighter has always played a vital role. Airfoil, as an indispensable part of fighter, has always been attached importance to research and development. Since the 1940s, the airfoil shape has undergone many significant changes, and the technical level has gradually realized from subsonic to transonic and then to supersonic. This paper mainly analyzes and summarizes the design characteristics and changing trends of the airfoils by analyzing the aerodynamic shapes of the first to fifth generation fighter airfoils. The performance that the airfoil needs to meet gradually improves over time. In the new era, the demand for airfoil design is more diversified. Countries pay attention to improving the aerodynamic performance, stealth performance, mechanical stress structure, material technology and morphing technology of airfoils. To meet the development needs of the new generation of fighter, this paper proposes that it is necessary to improve the level of stealth technology and morphing technology of fighters, and at the same time, improving of the CFD and the Navier-Stokes equations matter a lot. What’s more, the comprehensive application of multidisciplinary technology may make the future fighter more information and intelligent.

On April 27, 1900, the famous British physicist William Thomson (Baron Kelvin) delivered a speech entitled "The Dark Clouds of the Nineteenth Century on the Theory of Heat and Photodynamics" at the Royal Society. In his speech, he pointed out that, in the "edifice of physics" based on force and heat, there were two hypotheses that could not be solved at that time. One was the ether medium and the other was the black body radiation. Later, the flaws of physics were proved and the quantum mechanics and relativity were thus created. This paper introduces the origin of the concept of aether and the inference of its reality through subsequent scientific experiments. It also illustrates the emergence of a series of hypotheses such as blackbody radiation, which laid the foundation for the beginning of quantum physics.

Rational numbers can be serialized, in other words, rational numbers can be expressed in a regular, ordered way. This paper discusses the background, reasons and methods of rational number serialization, and also identifies the rules of rational number serialization, derives a unique sequence of rational numbers, identifies the expressions for rational number serialization, and lays the foundation for the use of rational number sequences in mathematics. The purpose of serializing rational number in this paper is to make transmitting and storing data more easily, and gives a better way for researchers to do further Mathmetics studies.

This paper deals with special classes of quartic polynomials and properties pertaining to their Galois groups and reducibility over certain fields. The existence of quartic polynomials irreducible over Q but reducible over every prime field is first proven, after which criteria are established for the Galois group of polynomials with this property. By constructing classes of V4-generic polynomials and comparing them with criteria put forth in previous studies for determining polynomials with this property, it can be shown that a polynomial of the biquadratic form x4 + ax2 + b has this property if and only if it can be written as x^4 - 2(u + v)x^2 + 〖(u -v)〗^2 with u, v ∈Q such that none of u, v, or uv can be expressed as ratio of two squares, and 2(u+v),(u−v)2 ∈ Z . The general form for biquadratic polynomials irreducible over Q and reducible modulo every integer n is found to have a general form similar to this one.

The hybrid flow shop scheduling problem is a flow shop scheduling problem that combines the two scheduling characteristics of the classical flow shop and the parallel machine. It is also one of the research hotspots in the field of shop scheduling. In this paper, the algorithm for solving the problem is reviewed, and the research status of the related expansion problems of the mixed flow workshop is summarized. Finally, combined with the development trend, the existing problems in the current research are analyzed, possible solutions are proposed, and the application of the algorithm for solving the problem of mixed flow shop scheduling in new fields in the future is discussed.

Robert J. Lang has proposed a theorem that when solving equations using multi-folds origami, general equations of order n can be solved using n-2 simultaneous folds. However, recently Jorge C. Lucero proved that arbitrary five order equations can be solved using two simultaneous folds. Combining this with the fact that one single fold can solve general quartic equations, the writer questions that whether the theorem may be altered into general equations of order n can be solved by n-3 simultaneous folds. Thus, in this paper, a method of geometric graphing -Lill’s method is used to try to solve six order equations with three simultaneous folds. By conducting case analysis using theoretical knowledge, it can be found that the six order equations can be possibly solved by three simultaneous folds. Besides, a comparison of solving equations with origami constructions and compass-and-straightedge is carried out. The result will encourage more research on using origami to solve higher order equations and inspire people to pay more attention to origami construction, which is more powerful, accurate, and efficient than the compass-and-straightedge people usually use.

Kagome materials haven been one of the recent research hotspots, which cause many important phenomena such as ferromagnetism and superconductivity. The present study analyzes the electronic structure properties of Kagome materials, which reveals that the energy band structure is effectively regulated by the electron hopping term and that its flat band properties will disappear when the hopping terms cannot cancel each other. Meanwhile, it is also found that the effective mass and velocity of electrons are significantly dependent on the energy band structure. The results would help us better understand the properties of Kagome materials and contribute to their industrial applications.

In the table tennis sport category, the different spin formula of table tennis ball will show different motion state, in which the important physical knowledge that is permeated aerodynamics. Besides the effect of aerodynamics, the balls can obtain different trajectories because of Magnus effect and Bernoulli principle. By using these three mainly professional knowledge, this paper analyzed the forces that the top-spin ball and back-spin ball acquired. What is more, the movement of side spin balls also be introduced through these professional knowledge. In addition to these analysis, 40mm and 38mm table tennis balls are compared in the paper. By using the principle of physical mechanics to reveal the secret and mechanism of the spin of table tennis ball, it provides a theoretical basis for improving the spin skill of table tennis ball.

In the current case of China's rail transit as a major part of public transportation, the complexity of the line has brought more transfer stations. After the investigation and observation, the long waiting time of transfer stations is one of the biggest problems at this stage. In the investigation of the transfer station, taking Chengdu as an example, the author chose the third-line transfer station with moderate universality and complexity as the research goal, and investigated the transfer efficiency and influencing factors. After the study and discussion of the conclusion, the author decided to establish a mathematical model to optimize and improve. For the more neglected problems, the fine regulation of the transfer station structure and the train schedule. The scheduling optimization model of this paper, as a universal and simple data collection model, can be universally applied. Meanwhile, this paper gives a new perspective on the rail transit transfer optimization, with the transfer time and passenger experience as the main consideration factors.

Using the finite element method to solve heat transfer problem in solid medium has been popular since last century, but heat convection effect in fluid medium makes the problem cumbersome to solve efficiently. Thermal transfer calculation of fluid medium is complicated, because solving heat convection and Navier-Stokes equation is hard. By making proper assumptions, intricate equations can be skipped, and it is possible to give rough estimate of heat transfer result through a simple and efficient calculation. Which is significant for design and verifiction of heating system for physicists and engineers. The study aims to solve the temperature distribution of a certain heat system, using finite elment method and with given assumpted air circumfluence. In the calculation, the room domain is subdivided into finite elments, and the boundary condition is given according to the heat influx and emmision, air circumfluence is introduced to simulate the effect of convection. The simplified model illustrated that the finite element method is effective in giving quantitative result of heat transfer calculation. It also qualitatively showcased the significance of heat convection, when the result is compared to calculation without any air flow.

Rocket propellant is an important part of the rocket. Solid or liquid propellant will burn in the engine combustion chamber, and then a large amount of high-pressure gas will be generated. High-pressure gas will be ejected from the engine nozzle at a high speed, generating a reaction force on the rocket, so that the rocket will advance in the opposite direction of the gas injection. This paper mainly analyzes the advantages and disadvantages of current propellants and conceives a theoretically feasible propellant selection method. The main method of research is to calculate the theory of each propellant and make diagrams. Some of the research data were based on existing research reports. Each fuel has its own characteristics, they have one aspect of excellent ability, such as heat conduction, high thrust, high reliability. This paper summarizes the characteristics of current propellants and provides a more convenient query for future researches.

The subject of this paper is the RedCap technology. RedCap devices (known as Reduced Capability devices) are a new technology that is being studied by 3GPP in the R17 phase of 5G. RedCap can be defined as a lightweight version of 5G technology. The IoT application scenarios are extremely complex and diverse, and different scenarios have different requirements for network metrics. RedCap devices have emerged to fill the gap left by the withdrawal of 4G, i.e., to cover the needs of medium and high speeds. Specifically, it was designed to cover the needs of LTE Cat.1 and LTE Cat.4. Therefore, this article will introduce the reader to Release 17 RedCap devices by describing them from multiple perspectives, i.e. the history of RedCap devices, application scenarios, requirements, and their technical features. RedCap devices are well-balanced in their capabilities, using simpler demodulation (meaning significantly lower RF and baseband requirements), targeting bands with smaller spectrum bandwidths, and reducing the number of transceiver antennas and the number of MIMO layers. These changes have resulted in a reduction in the rate of RedCap devices, a reduction in coverage capability, and an increase in latency. Based on these changes, RedCap devices are expected to be 2-5 times less expensive than 5G. The main applications for RedCap are wearable devices (e.g. smart watches), industrial sensors and video surveillance devices.

A n-dimensional topological manifold is defined as an n-dimensional local Euclidean space M that is also a second countable space and a Hausdorff space. If a topological space has a countable base, it is referred to as a second countable space. At the same time, continuous function and metric space can help people to understand topological space better. This article will express some basic ideas about continuous functions, metric space, topological space and its properties, and topological manifolds. Moreover, the paper shows some basic ideas of how topological manifolds, topological space and function could be recognized and proved. Through analysis, this paper demonstrates the connection between them, such as using properties of continuous function to prove the definition and properties of topological manifolds and spaces.

At present, the electromagnetic propulsion technology and the electrostatic propulsion technology are more mature than before. With the increase of available power on the spacecraft, the performance can be better improved. This paper mainly reviews the electric propulsion technology for long-term space travel. It can be concluded that, compared to traditional chemical rocket systems, electric propulsion systems are more suitable for long-term space missions and have the ability to transport relatively heavy objects in space.

The tube is a type of airplane that is shaped as a hollow cylinder. In common sense, it seems impossible that an airplane has no wings, however, the tube airplane can fly even longer in the sky comparing with normal airplanes. In this paper, the practical experiment related to Bernoulli’s theorem and Magnus Force will be introduced. In order to understand those equations more deeply with logic, a paper airplane model called “the tube” is going to be studied. The author makes the models with different shapes and angles so as to figure out the relationship between the angle of the index and the flying time of the airplane. Results show that the angle of the index has an impact on the time of the airplane staying in the sky, and the angle affects the angular and linear rotating speed of the airplane so that the time required for the airplanes varies.

Acquiring properties of microscopic particles helps establish modern physics models and theories, and detectors are the main method. This literature review researches on modern particle physics papers, summarizing the detection principle adopted for four types of particles, concluding the detection principle of the most commonly used detectors, scintillators, and summing up the use of scintillators in the four main kinds of particle detection. Based on the investigation, various kinds of detection materials absorb particles or their secondary particles based on different interaction mechanism in detection, and different kinds of particles have their suitable detectors. Scintillators are classified into three categories based on difference in physical properties, and detect particles by releasing energy during de-excitation in electric pulse signal forms. They can be made into large size, have relatively large detection efficiency and is suitable for γ ray detection. These ability gain scintillators a wide range of application in detection of the principal types of detectors.

The additive manufacturing technology of metal components is an advanced technology in the field of mechanical engineering and material science. Laser selective melting (SLM) is one of the most widely used methods in additive manufacturing. The temperature field of SLM process is the key factor to determine the quality of additive, so it has important research value. In this paper, the influence of laser power and additive speed on the temperature field of aluminum alloy additive manufacturing is studied by CFD numerical simulation technology. The results show that the CFD model can well simulate the SLM process. The additive temperature decreases with the increase of additive speed and increases with the increase of laser power. By adjusting the additive manufacturing parameters, the quality of additive manufacturing can be corrected and improved.

No transiting exoplanets have previously been found in the Pleiades. The Pleiades is a relatively young star cluster near us, which makes it valuable for investigation. This study aims to determine the existence of exoplanets in Pleiades using the transit method. Specifically, it sought to determine if the listed 83 stars have exoplanets by inspecting on light-curves from data of Transiting Exoplanet Survey Satellite (TESS). The TESS mission, with a better resolution and observed sky area than the previous Kepler mission, aimed to find more exoplanets around stars. To test the hypothesis that exoplanets do exist in the 83 stars of the Pleiades, we downloaded their light-curves using Jupyter notebook and the Lightkurve package, then checked using BLS method and fitting if there were transits. The results showed no clear sign of transiting planets in those stars. These results suggest that the 83 stars checked likely don’t have a transiting exoplanet, but 83 stars cannot represent the whole Pleiades star cluster. Other methods should be used in analysis to gain more accurate results and more stars should be checked to investigate whether or not transiting exoplanets exist in the Pleiades star cluster.

Quantum mechanics has evolved over the last hundred years and has had a profound impact on other fields. It is poised as a very powerful tool that can drastically improve our ability to carry out scientific research. This paper uses some concepts and examples to show how quantum mechanics influences many interdisciplinary applications. This paper first introduces the development of quantum mechanics to pave the way for the rest of the article. Then, the author selects two inventions to reflect the specific role of quantum mechanics. Finally, this paper also introduces two relatively advanced research areas, one is quantum computing and the other is quantum biology, with the basic framework and a simple and intuitive explanation provided, enabling the reader to see the recent study based on quantum mechanics. Through this paper, relevant researchers can not only draw a framework of quantum mechanics but also clarify some areas of future development.

Ornithopter, in the past, was a vehicle that appeared in science fiction movies and novels. However, due to advances in materials science and human research into aerodynamics, this fantasy is becoming increasingly possible. In this paper, the development history of the ornithopter is briefly described, and the research results of the ornithopter aerodynamics in recent years are reviewed. This includes the first draft of Leonardo Da Vinci's ornithopter design in the Renaissance era, to the modern ornithopter, as well as a summary of the results of the research on the aerodynamics of the ornithopter and prospects for future applications of the ornithopter. In this paper, through the introduction of the flapper and the discussion of the flapper dynamics, a more reasonable application field of the modern flapper and the prospect of the future can be obtained.

Since the actual use of the small windshield in Formula One (F1) cars is still unknown, the influence of the shape of the windshield edge on the driver's head will be the main research direction of this paper. In this paper, FLUENT is used to model three different shapes of windshield and the driver's head. The author analyzes the impact of windshield on the driver's head from the perspective of aerodynamics, speculates the actual use of different shapes of windshield, and gives some optimization schemes. Results show that the difference among the three shapes of windshield on the driver's head comfort is negligible, but the main role of the windshield is probably to create turbulence, allowing air to flow smoothly into the aerodynamic components at the rear of the car.

With the collection and use of large amounts of data in various disciplines, it has become a necessity to analyze these data that people cannot handle by means of mathematics and information theory. A review of statistical analysis on previous work like data analysis, data mining, and machine learning are conducted in this paper. Specifically information theory in conjunction with machine learning based on basic statistical evaluation are focused on. Many mathematical instruments are used in this area, including evaluating the performance, loss functions, and activation functions. In this paper，all these methods from previous work are concluded and the future potential development in this area is discussed. Finally, this paper broadly summarizes the development history about machine learning and information theory, and discusses the pros and cons of both of them and their future development.

This paper reports the first measurement of charged particle elliptic flow in Pb-Pb collisions at √(s_NN ) = 5.02T eV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed on more than 20,000 events in 40-50% centrality class on both long-range 2 < |∆η| < 4 and short-range |∆η| < 1 regions. The two-particle correlation method is used over long-range region, in the transverse momentum range of 1 < p_T < 1.5GeV , and the elliptic flow signals, given by v_n =√(V_n ) , are v_2 = 0.17 ± 0.01,v_3 = 0.07 ± 0.01,v_4 = 0.04 ± 0.01,v_5 = 0.03 ± 0.01. Since V_1 is obtained as -0.0013, it does not have a square root value. In addition, for n=2-4, it is found that v_n increases as p_T increases. The Q-vectors method is also used to determine the values of v_2. The magnitudes of the Q-vectors are fitted to a function. The values of v_2 produced by the two methods are compared and discussed. At the end, the vectors are used to analyse high-energy jet particles.

Nowadays gear is one of the most important mechanical components in the industry history, especially in the car industry and airplane industry. This paper demonstrates and explains the simulation for several specifical gears to object the static strength, stress on the gear teeth. By using simulation software Ansys, this paper collects data and analyzes to object the accuracy and efficiency from 3 fields in mesh size, mesh method and refinement of structure to ensure a better mesh way on gear simulation in the future, offer some references for better ways to mesh specific gears on Ansys.

Since the 20th century, countries have been conducting researches on near-spacecraft and have proposed a series of representative space vehicle concepts. This paper reviews the brief history of the development of reusable near-spacecraft and focuses on two combined cycle propulsion modes, SABRE and RBCC, with the goal of improving the performance of future near-spacecraft propulsion systems. An improving idea of combining the RBCC with the SABRE is proposed, and its possibility is discussed by analyzing the specific impulse curve. Two combining configurations of them and design principles are obtained by citing the literature and studying similar configurations. The two designs are also compared and the more optimized one is suggested, so as to offer some inspiration for future studies.

Rowing as an on-river sports has a long history dating back to the 16th century. The deeper understanding of fluid dynamics theory and the development of advanced material and manufacturing science and technology have inevitably fueled the continuous improvement on the world record of the rowing sports. The current paper focuses on the accurate extraction of the kinematics information including the boat’s location, velocity, and acceleration, resulting from the athlete’s rowing motion. A consumer-level digital camera is used for imaging the rowing motion at 50 frames per second from a distance, corresponding to a specific field of view ranging from 12 m – 36 m. Furthermore, due to large-scale imaging lens distortion, the physical resolution is varying significantly due to imaging location change. A video-specific calibration method using fourth order polynomials are developed to calibrate the physical resolution of each pixel based on the physical length of the boat. The resulting data is pixel-level accurate and provides detailed record for athlete’s training. The acquired information is extremely useful in gauging athletes’ performance and can be further analyzed to provide concrete technical improvement advice.

Accurate segmentation for Functional Tissue Units (FTUs) is a challenging issue in past decades. In this study, a model using the dataset of tissue section images will be built to evaluate and mark FTUs across five human organs as clearly as possible. We have the Human Protein Atlas (HPA) as training data and the data from Human BioMolecular Atlas Program (HuBMAP) as testing data. To balance accuracy and inference speed, this study applied Unext, an efficient network based on Unet, as the basic model. We also aim to use some tricks to further improve the performance of the model. First, we used several image enhancement methods to diversify the input image. Second, several structures like Feature Pyramid Network (FPN) and the Atrous Spatial Pyramid Pooling are added to improve model performance and convergence speed. As a result, we successfully segment functional tissue units among images of different sizes. Our proposed model scored 0.56 out of 1.00 by the judge of the competition.

Variable cycle engines (VCE) have always been a hot topic in aircraft engine research. Because of its variable thermal cycle characteristics, it has a wide range of optimum operating conditions (altitude, flight Mach number). In this paper, a typical double bypass variable cycle engine is used as the object of study, and the Gasturb11 software is used to simulate the engine in two main modes at different altitudes and Mach numbers, to observe the engine operation performance, as well as the relationship between the range and endurance from the derivation of cruise equation. The results show that VCE has a best thermal cycling pattern for a given altitude and Mach number, and for a range of lift-to-drag ratios, resulting in the longest range or endurance of the aircraft. This paper investigates the relationship between range, endurance and thrust of a variable cycle engine and altitude and Mach number to help make the VCE better suited to the needs of an aircraft with multiple missions, long range and high endurance.

Silicon Carbide (SiC) devices have the characteristics of high voltage resistance, fast switching speed, high working frequency, small on-resistance, and high-temperature resistance, and have broad application prospects in high voltage and high-power occasions. However, the application of SiC is faced with the problems of high-frequency switching transient voltage, current overshoot, ringing, and short circuit protection. Based on the problems encountered in the application process of SiC power devices, the characteristics and drive protection technology of sic devices are studied in this paper. In this paper, the static characteristic parameters of SiC device are studied, the switching characteristic parameters are tested, the influence of parasitic inductance parameters on the switching characteristic is analyzed, and the design method of PCB Roche coil is analyzed, the anti-interference performance of loop winding turns is analyzed and the driver protection circuit is designed.

This study focuses on the classification of multi-cluster events based on a parameterization of data from a time projection chamber using machine learning. Samples containing a mixture of single and overlapping two-cluster events, both in one and two dimensions, were studied using multi-layer perceptrons and other MVA algorithms provided in the Scikit-learn package. The classification was based on various sets of features and classification accuracies of up to 97% for 1D clusters and 97% for 2D clusters were obtained. This study demonstrates that the efficient classification of signals for further processing through machine learning is feasible and efficient.

As the development of the Brain Computer Interface, it can be a possible way for human to control the external devices by the mind. This can be good news for the handicapped people whose life qualities are greatly decreased. In this paper, designed an assistive robot arm for those disabled. The assistive robot arm mainly contains a filter, a microcontroller and a motor drive system. The filter can filter out the noises while the microcontroller judging the brain signals and turn it into an actual control signal. The actual control signal will finally drive the motor and for the sake of safety and stability, a PID circuit was add in the motor drive system. The mechanic arm designed can turn what people think to the actual robot behaviour and this will obviously increase the life quality of the disabled people. It’s also a light weight system with a wide range of versatility and will bring benefits to all the handicapped.

Engines are very important for human-beings and it is necessary for people to find a perfect kind of engines since they are used in many vehicles. In this paper, it will mainly focus the traditional engines and the hybrid engines, and compare there main performances including economical performance and environmental performance. For economical performance, researches have found that hybrid engine has higher thermal efficiency and lower thermal efficiency loss compared with traditional engine because hybrid engine does not have the inherent defect of crankshaft linkage mechanism as traditional engine. Also, since hybrid engine is consist of both electric motor and internal combustion engine, consequently it will have lower fuel cost. For environmental performance, hybrid engine not only reduce the consumption of non-renewable fuel but also more environmental since using electric to give vehicles power is relative environmental than using fuels only like traditional engine. This paper also find that both traditional engine and hybrid engine have development prospects in the transportation industry.

Linear regression analysis is one of the most basic and vital methods in statistical applications, especially when examining the relationship of one or more variables. This method initially used to analyze the relationship between father and child height has also been developed for nearly two hundred years. The development of computer technology has brought more efficient and accurate data processing, which allows us to use linear regression models to deal with high-dimensional and more complex scenarios. This paper mainly elaborates on the development of high-dimensional linear regression and the most classic models and tries to understand how some models can be improved. Finally, how to accurately apply model theory to practice will be a significant research direction in the future

With the social progress and the rapid development of people's economic level, people pay more and more attention to the external image of bridges, which greatly promotes the emergence and development of special-shaped arch bridges. But because of the particularity of the special-shaped arch bridge structure, its plane stress characteristics, which are different from the traditional arch bridge, become more complex. In this paper, three types of arch bridges commonly seen in special-shaped arch bridges: leaning type, inclined span type and butterfly type arch bridges are selected for a brief structural stress analysis. The results show that most of the arch structures of special-shaped arch bridges only play an auxiliary role in bearing loads, and due to the more complex stress, the finite element analysis software needs to be used to optimize the structure for many times to reach a relatively reasonable range. In addition, some arch structures are used more for aesthetic purposes than to bear loads, and their mechanical performance is basically zero.

Australian Institute of Health and Welfare states that about 18% of people in Australia, which is 4.4 million, suffers disability. Hosseini et al argued that physically disabled people experience more restrictions in social activities than healthy people, which are associated with lower level of well-being and poor quality of life. To improve the life quality of disabled people, a study is carried out to determine an effective and accurate way to realize what disabled people think. Although there are similar products been made, the previous built products are heavy, clunky, slow in response and inaccurate. In order to solve the problem, an integrated circuit (IC) with a microcontroller is used instead of a laptop and a control system is also implemented to accelerate the response and improve the accuracy. An isolating circuit is implemented as well to improve the stability and durability of the system. Experiment result shows that the IC implemented weighs around 5g, which is 400 times lighter comparing with previous products. The deviation is controlled to be within 2% and the response time is measured to be 0.5s the power consumption is measured to be less than 100μW, which is well within the budget.

Today's VR games on the market use computers to connect a head-mounted monitor and two grips to build a virtual game world for players, providing players with a fresh sensory experience. However, the current VR game only uses the player's hand movement as a way of human-computer communication, the way is relatively single, and the player can not express their desire to play through only two hands, which cannot fully express the player's will. There are currently two types of motion capture used in consumer VR devices: optical capture, which is based on inertial sensor motion capture. These two are faced with the problem of extremely high cost and burden. The ultra-broadband system has the advantages of high positioning accuracy, low latency, cheap price, being light and portable, etc., which is very suitable for this kind of application scenario. This paper considers using two main technologies RTT ranging motion recognition and keyframe to achieve the aim.

Deep learning is an intrinsic learning style and representation through which knowledge acquired helps interpret data such as words, images and sounds. The ultimate aim is to enable computers to analyse and recognize data, such as words, images and sounds, in the same way as humans. In artificial intelligence, loss function is a very effective method. In the deep study, the loss function is used to determine the relationship between the target and the prediction. This paper analyzes and summarizes the loss functions in face recognition, object detection and face recognition, and focuses on some key loss functions.

As a part of image recognition, Chinese character recognition has a great application market in China, such as license plate recognition, logistics information recognition and so on. In recent years, the application of CNN has set off a frenzy of computer vision. Especially in the task of image recognition, CNN is widely used because of its high accuracy and few calculation parameters. However, CNN’s local operation of using repeated filters to process images also has its shortcomings, for example, it can’t pay attention to the relationship between distant pixels in the image. To solve this problem, we tried to add non-local operation to CNN to improve its performance. We chose the classic model of ResNetV2-50 as the foundation, and added non-local blocks to it. We compared the results of the two models and found that the accuracy increased by 4%.

The total weight of the minimum spanning is the smallest in the connected graph. It can be used to solve many practical problems in urban life. Prim’s algorithm and Kruskal’s algorithm are greedy algorithms for solving the minimum spanning tree problem. But they make greedy choices in different ways. The paper focuses on two greedy algorithms for solving the minimum spanning tree problem. The author will evaluate each algorithm’s complexity and determine their most suitable condition as well. The author compares the running process of the two algorithms and analyzes the relationship between their algorithm complexity and the number of edges, which can describe the sparsity of the graphs. The result shows that Kruskal’s complexity is related to the number of edges, so it is better for sparse graphs. Prim’s complexity is related to the number of vertices, so it is better at analyzing connected graphs with lots of vertices, that is, dense graphs. As a consequence, Prim’s algorithm is better for dense graphs.

Stepper motors work stably, are not affected by external factors, and errors do not accumulate. These advantages make them mostly used for open-loop control, so the control system is simple and is widely used in machinery, instrumentation, and automation fields. In this paper, three kinds of stepper motor driving circuits are designed based on the use of specific chip driving methods, using L297, L298 and ULN2003A driver chips, and AT89C51 microcontroller, respectively, and each circuit is introduced in detail in this paper. Each of these three circuits has different functions and requires different operation methods to achieve control of the stepper motor. By comparing the functions, application scope, and operation methods of the three circuits, it is concluded that the third driver circuit, which is composed of AT89C51 and ULN2003A, is widely used and convenient to use.

This paper presents a way to determine how lead influence the detection rate of muon at the earth’s surface. There are four sets of data on different thicknesses of lead above the detectors included in the experiments, and the largest set has 45054 groups of data. After using python modules to analyze the data of muons and other background particles such as electrons detected by desktop muon detectors, the discussion about identity of muons, especially about the detection rate, was conducted, as well as their relations with other factors. Then, the comparison was made between the average rate of muon detections of varied thicknesses of lead above the detectors to define the correlation between them. The result of data analysis mainly demonstrates an exponentially decreasing relationship. Accordingly, the calculation of the attenuation coefficient of lead which influences the exponential relationship was conducted as well.

With the maturity of UAV technology, drones can carry different instruments in the air to help people complete their work more efficiently. However, different working environments also bring different challenges to UAV control systems. This paper mainly discusses the quadrotor UVA and compares the stability of the Proportional Integral Derivative (PID) controller and Active disturbance rejection controller (ADRC) under the disturbance of gusts at sea. The flight principle of the quadrotor and the dynamic model of the quadrotor will be discussed on this basis. Then the composition and mathematical formula of the PID and ADRC controllers are introduced and compared. In general, this paper focused on the anti-jamming ability of different controllers under the influence of gust, which shows that although the ADRC controller has a more complex system and tedious parameter adjustment process in comparison with the PID controller, it has excellent anti-gust interference ability and can better serve the offshore operation of UAV.

The rear spoiler is one of the main components that affect the aerodynamic performance of the F1 racing car. At present, numerical simulation technology is becoming a research hotspot to study the aerodynamic performance of the F1 racing car. In this paper, we discuss the F1 racing car rear spoiler airfoil selection and three-dimensional design and use three-dimensional simulation software to calculate the impact of different attack angles, velocity, and airfoils on the rear spoiler’s drag force and negative lift. The results show that the RAE2822 airfoil has a good lift-drag ratio at low velocity. When the attack angle is 30°, the maximum lift-drag ratio can be obtained. When the velocity exceeds 60 m/s, the impact on the lift-drag ratio is almost negligible.

Gliese 486 b, also known as GJ 486 b, is an exoplanet orbiting around a red dwarf near our solar system. The celestial body is fair target for TESS to observe and related data of it have been collected by TESS. This paper firstly focuses on methods used to obtain planetary parameters and the theoretical base behind them. Then, it turns to some further calculation with our best-fit data, and analogy to the methods that previous researches used. Finally, the paper introduces analysis on the changing period and the relevant potential causes. The paper concludes with some discussion on directions of future investigations.

In this paper, we present some light curves and schematic diagrams related to our methods. The data released from TESS are our basic resources for finding exoplanets. Exoplanets may exist inside both single stellar system and multi-stellar systems. We will present 4 planets according to our findings. However, we first carefully chose 2 binary systems from a catalog of 4584 eclipsing binaries to give a fundamental analysis through details in the light curves. Then comes the ways of detecting exoplanets inside extrasolar systems, mainly transit, radial velocity (or Doppler method) and microlensing. The methods also yield some of the properties of the exoplanets, such as their orbital period, mass, radius, etc. Finally, we will talk about both the advantages and disadvantages of our methods, and with some future improvements. We use python to help us visualize the data observed in the light spectrum, and the code will be placed in the last part of this paper.

The creation of the diffusion model was a piece of exciting news in the deep learning community. Millions of people are excited to try the new DALLE 2 AI artist and the state-of-the-art stable diffusion model. One of the greatest advantages of these AI artists is that they can apply many distinct artistic styles to the same image. Nonetheless, the image created using a specific artistic style sometimes seems too strong or too weak. The ability of adjusting the strength of artistic styles of the generated images enables users of this algorithm greater degrees of freedom in terms of creating images of their wishes. Moreover, the ability of adjusting the strength of artistic styles of the generated images can also serve an educational purpose from which users can understand artistic styles in concreate terms. This paper proposed a novel method of adjusting the level of artistic styles of the generated image which utilized the continuity of the latent space of the Contrastive Language-Image Pretraining (CLIP) encoding and calculate the augmenting latent vector. This novel method provides a greater level of tailored manipulability of the generated image.

With the Beijing Winter Olympics, curling has become one of the big hits. To research, professional curlers will brush ice at 40 ° - 60 °, because the curling brush is a universal head when the force and the direction are fixed, changing the curling deceleration movement. This work aims to use Solidworks modeling, Unity virtual simulation, mathematical regression statistical prediction, and MATLAB data visualization to find the most suitable gimbal pole angle under the integration of the sports and physics, to make curling adjustable and provide a reference for improving its competitive level. The conclusion represents the gimbal pole angle is 54.7°, and the angular acceleration is 17°rad/s², which slows down the curling deceleration and has a longer relative displacement. At 60.1°, the angular acceleration is 31°rad/s², relative displacement is the shortest. So as to help athletes formulate real-time strategies, and also promote curling to be better popularize and theoretical.

Due to the widespread application of semiconductor technology in integrated circuits, more and more design studies on analog integrated circuits are gradually being implemented. However, due to the nature of analog integrated circuits, it is time-consuming and inefficient. Therefore, there are lots of experts studying how to reduce the design cycle of analog ICs. The use of machine learning in analog circuits stands out, as machine learning-based design methods have significantly reduced the analog cycle time. This review report will first introduce the algorithms related to machine learning, and the second half will outline the existing applications of machine learning in an analog integrated circuit and compare them.

Since the discovery of the Radiation belt, scientists have had strong interests in the magnetized space that protects us from the bombardment of solar storms. Early satellite observations show that the radiation belts consist of energetic particles and exhibit a two-belt structure. The outer belt electrons are accelerated during geomagnetic storms, while the inner-belt is mostly formed by the cosmic ray. Recently, the NASA Van Allen probes discovered a temporary storage ring that locates in the middle of the two belts when solar storm event occurs, and the radiation belts may exhibit a three-belt structure. This study aims to analyze the three-belt structure from short-term variation and long-term variation. We calculated the decay time scale in the heart of the radiation belt which describes the lifetime of the high-energy electrons. The study of the decay time is of great significance in understanding the dynamics of the whole radiation belt.

In this paper, the third generation power MOSFET is introduced, and the physical model based on silicon based MOSFET is improved for SiC MOSFET, and the commercial planar gate and trench gate 1.2kV SiC MOSFET are simulated. The accuracy of physical modals is tested by comparing the static characteristics with commercial ones. The dynamic characteristics of two MOSFETs are simulated by inductively clamped double pulse circuit, and the circuit parameters are analyzed according to the static characteristics of the devices. The switching loss of the two MOSFETs is calculated and compared by using TCAD software. In the two devices with the same volume, the trench gate structure has the larger switching loss.

The relation between the abelian extension of a field and the topological groups of the field itself can be constructed using class field theory. In this piece of writing, the author will introduce the fundamental theorems of local class field theory by conducting a method of literature study. These theorems are the Reciprocity Law and the Existence Theorem, respectively. In addition to that, the author will discuss several unresolved issues in class field theory and provide examples of their applications in number theory. In class field theory, the results can be shown in two different ways. Both can be considered broad strokes. The first step is to demonstrate that the local case is true. By employing the methodology of cohomology and the theory of Lubin and Tate, one can demonstrate the Local Reciprocity Law and the Local Existence Theorem. The fundamental theorems in the global case are going to be demonstrated by utilizing the local results in conjunction with cohomology. Directly demonstrating the Gocal Reciprocity Law is another viable option.

Recent year, as technologies and research have unprecedently grow in a fast speed, human’s exploration toward outer space become enormous. Several private space exploration and aerospace manufacture corporations, such as SpaceX, have come into public which symbolize the development of human society and start to reshape the human civilization. Near Earth Objects(Neos) or Potential Hazard Asteroids(PHAs) have gradually focused by scientists. With the emerging of Neos ’observations, it has become vigilant that Neos ’impact to human civilization is obviously destructive refer to the distinction dinosaur. Neo impact technologies and strategies are tremendously vital in resort of continuing human civilization. This paper presents the time frame of launching of satellite and space station and their function of exploration and the information about near earth objects including its feature and propose several possible solutions toward Neos for short time scales and long times scales including nuclear explosive devices, kinetic impactor, asteroid gravity tractor and asteroid laser ablation. These methods have been list with their advantages and disadvantages and evaluation will be taken from the prospective of successful rate, time, efficiency and cost.

The rear spoiler of an F1 racing car is the main component that affects its aerodynamic performance. In the race, it is necessary to select the wing with different characteristics according to different track characteristics. In this paper, computational fluid dynamics (CFD) technology is used to study four different types of stationary airfoils, analyze their aerodynamic performance under three different track conditions, combine the characteristics of the track for quantitative analysis, and finally target the most suitable airfoil. Airfoil 2 is suitable for track 1 - Spa Francolchamp, a track with many curves and changeable climate, because of its medium negative lift value. The high negative lift force generated by airfoil 4 is applicable to the high altitude track, for example, Track 2 - The Rodriguez Brothers Track in this study. For airfoil 1, the lowest resistance value is applicable to track 3 - Silverstone, which is a track with many straight tracks and high-speed curves.

In this study, we developed a machine learning algorithm for crop recommendation based on a dataset containing environmental features and corresponding optimal crop choices. The algorithm was trained on a set of seven numerical features, including temperature, humidity, pH value, rainfall, and levels of nitrogen, phosphorus, and potassium in the soil. We evaluated the performance of multiple classification algorithms, including naive Bayes, logistic regression, support vector machine (SVM), decision trees, random forests, and neural networks. Our results showed that neural networks performed the best. However, SVM, which provided only unsatisfactory results initially, also achieved pleasing results after we redesigned its structure and adjusted its parameters. This system has the potential to assist farmers in choosing the most suitable crops for their specific environments, leading to increased crop yield and profitability.

With the continuous improvement and development of global BIM technology, BIM technol-ogy has gradually penetrated all stages of the construction industry. Construction enterprises can use BIM tech-nology to further improve the building design, construction, cost, and other work. Improve building quality and construction efficiency. However, how to truly apply BIM technology to actual construction projects is still a huge challenge. This paper first combines the theory and characteristics of BIM technology, analyzes the construction process of BIM technology applied in actual engineering projects as a starting point, and studies the feasibil-ity analysis of BIM technology in engineering projects by reviewing the literature. And some problems exist in BIM technology and give corresponding suggestions. The utilization rate of BIM technology in all stages of the construction process is improved, the development of BIM technology in enterprises is promoted, and more BIM technology application-oriented talents are cultivated for enter-prises.

The A/D conversion circuit is an important part of switching power supply equipment, and the circuit design has a great influence on the conversion accuracy. This paper mainly discusses the current mode circuit, gives the difference between it and voltage mode, and studies the design idea and circuit of the A/D conversion circuit. In this paper, the current mode circuit is composed of basic components, and the A/D conversion of the switching power supply is realized by switching current mode. The reason of A/D conversion error is that when the current mirror is not strictly matched, it is caused by the limited input and output resistance of MOS tube, and an operational amplifier is added between the drain and gate of the current mirror to improve the A/D conversion accuracy. The results show that the current mode is used to realize A/D conversion, which has low power consumption and fast conversion speed.

Due to the advancement of technology, laser communication, fiber optic communication and optical quantum communication have been developed, not only in the field of life, but also in the field of aviation, military and information security. This paper, mainly compares the difference between optical quantum communication and other communication technologies in terms of security and effectiveness, presenting the current state of technology and applications and providing an outlook on future directions. Through the comparison, this paper argues that the application of technology in optical quantum communication can promote the rapid development of quantum communication technology and thus enhance the comprehensive strength of global communication technology.

Heisenberg deduced the famous uncertainty principle which shows that there exist several conjugated quantities that can never be measured precisely at the same time. Further, Copenhagen interpretation gives a new perspective about quantum mechanics, which claims that particles do not have properties like position or momentum until people measure it. Hence, the famous EPR paradox was proposed to question the realism and locality of Quantum mechanics, which leads to the Hidden Variable explanation. However, this theorem was proved wrong by John Bell in 1964 with Bell Inequality. In addition, Hidden Variable Interpretation was developed by De Broglie and Bohm, they came up with the Bohmian Mechanics, which can be considered as Non-local Hidden Variable theorem. This interpretation gives physical meaning to waves. Unlike Copenhagen Interpretation, this theorem claims that particles do have a determined position. Some people may argue that it can be proved contradicted by using the Turing method (self-reference). Because if the algorithm represented by physics law described Hidden Mechanics to determine particles’ state, then the future is determined and predictable. Therefore, another algorithm can be established based on that, which will lead to “Liar Paradox”. This article will briefly introduce the uncertainty principle and some interpretations about quantum mechanics. Furthermore, this article will combine some ideas in Alan Turing’s Halting Problem to the universe of non-local hidden variables as a thought experiment, which involve self-reference, to give an interesting result of locality and determinism.

The paper analyses the significance of reactive power optimization, generalizes the current situation of power system development. Various optimization algorithms were introduced in this paper such as traditional optimization algorithm, intelligence optimization algorithm, including the methods of linear programming, Newton’s method, heuristic optimization algorithm, etc. This research analyzes the advantages and disadvantages of each algorithm and its application direction by comparing their outstanding performance in solving discrete variables and continuous variables. The purpose of the research is to find the optimal solution of reactive power optimization algorithm, minimize the transport network loss of power system, and improve the quality of users.

5G is another age of broadband portable correspondence innovation including high speed, low latency, and large connectivity, and quantum cryptography is a technology of the combination of quantum mechanics and cryptography. In order to combine 5G fronthual with the QKD (quantum key distribution), we conduct research on this paper. First, this paper proposes DWDM-QKD (dense wavelength division multiplexing-quantum key distribution) 5G fronthaul architecture. It contains AAU (active antenna unit) sites, multiplexer, de-multiplexer, and DU (distributed unit) sites. Second, the spontaneous Raman scattering noise interference model is analyzed theoretically, and the secure key rate calculation theory is used. Finally, the simulation evaluates the performance of QKD in the proposed architecture, the reduction of classical power can lead to an increase in the secure key rate.

A common problem about currency denomination is the change-making problem. In this paper, a generalized denomination-related problem inspired by the optimal denomination problem is discussed, namely the bilateral optimal denomination problem. The solution maximizes a certain monetary value and thus can be applied in pricing strategies. Two key issues need to be addressed. One is how to properly formulate the problem in mathematical language. The other is how to compute the corresponding result with an algorithm. The paper learns from existing denomination algorithms and provides a solution to the problem from construction to implementation. Some limitations are needed to improve the practicality of the solution. An example of threshold discounts is used to illustrate the real-life application of the proposed problem.

Turbochargers are one of the most important inventions to facilitate internal combustion engines. This paper is a thematic review of the technology of the turbocharger with emphasis on its workings, influencing factors, applications, problems, solutions and related or derived technologies for purposes outside the motoring industry. This paper reveals that the turbocharger resembles a modeled heat machine with thermodynamic processes for boosting engine power output with exhaust gas flow. It gives rise to various problems including inefficiencies, lags and conditions to be met, etc. As solutions, various mechanisms have been developed, as well as special modifications such as multiple turbochargers. E-boosting, gas turbines and microturbines have been discussed as related technologies with similarities in principles or origins that are of use in the power generation processes from various points of view, including principles, working conditions and efficiencies.

Wind-induced risk accidents of cable-stayed Bridges exist all the time. It is important to evaluate the wind-resistant risk of cable-stayed Bridges. In order to better reduce and avoid risks in cable-stayed bridge engineering, this paper collates and analyzes previous studies, combines Bayesian network model with practical engineering problems, and establishes a risk assessment model for wind resistance risk assessment of cable-stayed bridge. Taking Humen Bridge in Guangdong Province of China as an example, the paper carrying out relevant derivation and discussion.

The performance of Stirling engine regenerators has a huge influence on the efficiency of Stirling engines. Hence, the Stirling engine design process focuses on the study of the engine regenerator. To find out possible ways to improve regenerator performance, scholars from different countries have done a lot of research on analytical methods and factors affecting heat flow in the regenerator. Whereas, different ways of modelling are used in these studies, and the results are not organized so well. The present work aims to summarize and arrange other researchers’ work and then provide evidence for practical improvements and optimization. In addition, this work clearly shows the aspects of regenerator analysis, which enables new researchers to better find their orientation.

Based on the rapid development of quantum computing and quantum communication all over the world, this paper studies the latest development of quantum computing on the basis of consulting a large number of literatures. By analyzing literature and summarizing, the basic knowledge and concept of quantum computing, the theory of time and data complexity, quantum computer, and the technical route of quantum computing are studied. Through the research, it is found that quantum computing is still in the primary stage, and the hardware of quantum computing, quantum error correction, anti-noise quantum computing and quantum simulation all need further research to improve quantum theory.

This paper clarifies the necessity of studying three-dimensional spatial data models, analyzes the research progress and existing problems of topological spatial relationship description methods, and proposes a complete and formal description framework of three-dimensional topological spatial relations based on point set topological theory and dimension expansion method. On this basis, the topological spatial relations existing in three-dimensional spatial objects are classified, and five fundamental topological spatial relations are defined. The mutual exclusivity and completeness of the minimal set of 3D topological space relations are proved. Based on point set topology and k-dimensional pseudo-manifold, this paper proposes the formal description of three-dimensional topological properties and spatial relations between spatial entities. The simplicial homology is applied to manifolds, the topological properties of three-dimensional space entities are revealed, and the formal description method of three-dimensional space entities is given through the geometric structural relationship between simplex and simplicial k-complex.

With the progress of science and technology, sound source localization technology has a wide range of applications in urban traffic, digital hearing AIDS, mechanical systems and other fields, especially in noise monitoring and other aspects. In order to solve problems such as failure risk, this technology can accurately determine the location of the problem. At present, low-end manual technology is used in many fields, which is inefficient and a waste of time. Therefore, this paper designed a sound source signal positioning and tracking system based on STM32. The system takes STM32F407VET6 as the control core, and the speaker as the sound source that can emit self-defined regular sound. After the amplification circuits, it is sent to the microcontroller for processing.After sampling, the distance and offset Angle between the test point and the sound source are calculated by calculating the time deviation of the sound signal collected by the two microphones. Then control the steering gear rotation and laser alignment to realize the positioning and tracking of the sound source, and display the distance and offset information between the test point and the sound source in the terminal. With the development of modern technology, sound source localization can be widely used in daily life, and with the development of machine learning, cloud computing and electronic technology, this technology will have a broader application prospect.

Under the background of the times, Smart Operating Vehicle has wide application prospects. This paper designs a Smart Car based on STM32F103RCT6 MCU, which combines the functions of OPENMV digital recognition module and infrared route tracing, in order to realize the function of the car to reach the designated location and start its operation. The scheme in this paper breaks the limitation of conventional manual work and can replace manual work in extreme environments such as high temperature and small space, which fully reflects the era significance of smart hardware.

The 3x+1 Conjecture is a notorious open elementary number theory problem for its deceitful triviality. Several algorithms described in the past for the numerical verification for the convergence, one of which implemented an improvement of sieves. However, most papers focused on theoretical aspects of the sieve, and empirical results were rarely discussed. This paper presents data from implementing sieves on a relatively high-level language, as well as some helpful unmentioned rudimentary algebraic facts about sieves. Several algorithms for convergence verification of the 3x+1 Problem had been developed since the 1970s. This paper tests an algorithm presented in a 1999 paper and explores the runtime growth to input size.

In order to explore the optimization of composite wing structure, this paper reviews the past research works of optimization of composite wing structures worldwide and in China. It concludes that most optimization methods and calculations are useful but only applied with specified theoretic model. Then relevant composite optimization theories and strength constraints with composite lamination failure criteria, stability, aeroelasticity are sorts out. Optimizing algorithm and applied solution rounding strategy are also listed. Concentrating on weight-reduction analysis on the thickness, sequence, and angle of the composite stacking under multiple constraints, a practical model of a composite wing structure example with a large aspect ratio is completed, and the calculation is based on the finite element analysis tool Nastran and the genetic algorithm Matlab program. Two optimal solutions are given with detailed differences and the comparison of the composite structure parameters before and after calculation is also recorded. The application example indicates the feasibility of the optimization method and quadratic rounding process, the detail structure performance improvements with skin lamination change under the calculation are illustrated at the same time.

Options as a type of financial derivatives have become increasingly popular in recent years; therefore, understanding how to value options as a derivative is crucial. To analyse the problem, we can use mathematical stochastic analysis from the perspectives of risk management and return maximisation, and then develop an option valuation model. Using a literature restatement approach, the mathematical model of option valuation is examined in this study. Bachilier introduced the option valuation model in 1900 as a breakthrough in the study of financial mathematics. In the 1860s, the asset pricing model was introduced, followed by the famous B-S formula published by F. Black and M. Scholes, which is also used to research option valuation. The above-mentioned mathematical models have been refined and are now frequently utilised in the options market. They can also be used as a criterion for buyers to determine the value of options, thus it is important to investigate this subject, which will be the subject of this paper.

Blackjack is a popular casino poker game in which players make drawing decisions based on rules other than the size of their points. We found that despite the randomness of the card draw, blackjack is actually very mathematical and logical. By calculating probabilities and using game theory, we can allow players to make relatively "rational" decisions that maximize their expectations of winning, rather than relying solely on guesswork and vague feelings. Therefore, in this article, we built several models to simulate a blackjack game with different numbers of people. For players in each model, we give them a code that outputs the optimal decision, which helps them figure out the winning percentage (more specifically, the expectation, since once stakes are involved in multiplayer games, the winning percentage doesn't necessarily represent the expectation of winning money) for each decision, thus helping the player make a better decision.