bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on High Sparse Sampling CT Image Reconstruction Algorithm Based on Convolutional Neural Networks
Authors: Luo Jiqing , Luan Feng , Liu Zhuxi , Zhu Junan , Song Lai , Wu Yuetong
Published: May 2021

CT plays an important role in medical diagnosis and industrial nondestructive testing. How to reduce the radiation to patients in the process of CT scanning has become a hot spot. An effective way is to use sparse sampling projection data to reconstruct the CT image. However, the image obtained by using the traditional CT reconstruction algorithm to deal with the sparse projection data has serious image distortion and artifact. This paper presents a CT reconstruction method based on CNN. This method learns the mapping relationship between the sparse projection data and the complete projection data in the training database, and uses the learned result to process the sparse sampling projection data. FBP algorithm is used to get the high resolution CT image. This paper uses CNN to carry out an end-to-end learning to repair the projection sinusoidal image with missing angle and improve the quality of CT image reconstruction.
The Exploration of Aerospace Engineering Project Management Method Based on System Engineering
Authors: Li Luning , Meng Ju , Yang Lingxiao , Cui Yapeng , Zhou Yongjun
Published: May 2021

Aiming at aerospace engineering project management, the practice of system engineering is given, and the difficulties and problems existing in aerospace development and the management contents that need to be strengthened in the future are put forward in this paper.
Research on Distribution Network Fault Recovery Reconfiguration Considering Distributed Generations
Authors: Guan Wanlin , Chen Cong , Lan Tian , Liu Yanlong , Rong Shuang , Jia Wenbo , You Chao , Liu Xinkai , Liu Huanyu
Published: May 2021

In view of the increasing penetration rate of distributed power in the distribution network, the traditional fault recovery reconfiguration method of distribution network needs to be further improved. An economic optimization model of distribution network fault recovery reconfiguration considering different types of distributed generations is proposed. This model takes into account the minimum number of switching operations as target and considers the impact of network active loss on restorative reconfiguration. Integer coding quantum particle swarm optimization algorithm is applied to the fault recovery reconfiguration optimization model and a fault recoverability discriminant method is presented. This method can classify the fault network into recoverable power-lossing area and non-recoverable power-lossing area. Recovering the fault recovery method given by the recoverable power loss area, and restoring the power supply to the unrecoverable power loss area according to the distributed power supply condition connected to the area. The simulation results show that the proposed method can be applied to the fault recovery reconfiguration of distribution network with distributed power accurately and efficiently.
Forecast and Suggestions on The Demand of Lithium, Cobalt, Nickel and Manganese Resources in China’s New Energy Automobile Industry
Authors: Hu Song , He Sichao , Jiang Xiaotong , Wu Meng , Wang Pan , Li Longhui
Published: May 2021

As the key resources of power battery production, lithium, cobalt, nickel and manganese have become important factors to ensure the healthy development of new energy automobile industry. In this paper, the distribution and application status of lithium, nickel, manganese and cobalt resources are introduced and briefly analyzed. Combined with the development trend of new energy automobile industry, the demand of lithium, cobalt, nickel and manganese resources in China’s new energy industry is reasonably predicted. It is estimated that during 2021-2025, 76,000 tons of lithium, 88,200 tons of cobalt, 219,600 tons and 128,000 tons of manganese will be consumed. Because there is a big gap between supply and demand of resources, it is suggested to enhance the development of local resources, optimize the overseas resource supply system and build a closed loop of resource recycling.
Analysis of The Impact of The New Infrastructure on Economic Growth——Based on Empirical Test Charging Pile of New Energy Vehicles
Authors: Yu Huanyang
Published: May 2021

Nowadays, with the digital economy gradually involving in the original economic state in China, Chinese industries have been undergoing economic transformation and upgrading. Specifically, Chinese society has a stronger demand for new information technologies such as 5G, big data and artificial intelligence accordingly. In the future, the new infrastructure is expected to play a key role in the high-quality development of China’s economy. Based on the information above, this paper summarizes the current academic research on the new infrastructure and explains the transmission mechanism of it to promote economic growth from six different effects. To verify the theory, this paper takes the charging pile of new energy vehicles as an example, using regression analysis of China’s provincial panel data from 2016 to 2020 to draw a significant positive conclusion, which is aimed to better meet the new infrastructure era and realize a new round of great development.
Analysis of Influencing Factors of New Energy Vehicle Satisfaction Based On Scenario Thinking and Catboost Model
Authors: Zhang Fan , Yang Jing , Liang BenShuang , He Hongjing
Published: May 2021

In order to accurately grasp the influencing factors of consumer product satisfaction with new energy vehicles, this paper uses scenario-based thinking as the framework and a large amount of multi-source heterogeneous data as the basis. Dimensional matching is performed on the structured data, and the random forest machine learning method is used to obtain complete sample data to reflect the overall market characteristics; thus, the CatBoost model is trained based on the complete sample data, and the degree of influence of each feature on satisfaction is analyzed. Through research and analysis, it is found that not only the performance of the product itself has a greater impact on product satisfaction, but the characteristics of consumers’ own attributes are also an important factor affecting product satisfaction. Based on the research conclusions of this article, it can provide reference and basis for the improvement of enterprise product satisfaction and precision marketing.
Research on Online Monitoring System for Dielectric Loss of High Voltage Equipment in Substation
Authors: Guo Yun , Xu Minhu , Zhang Hang , Zhang Rui , Zhang Kexin , Zhou Yang
Published: May 2021

In view of the remote collection of voltage and current in the online monitoring system for dielectric loss of high-voltage capacitive equipment in substations, it will lead to the problem of difficult to guarantee collection synchronization and large data transmission. The paper cleverly borrows AC 220V voltage as the reference phase, current and voltage monitoring terminal Calculate the phase relationship between the current, voltage and the reference phase of the capacitive device, and send it to the master station as an intermediate result. The master station calculates the dielectric loss of the capacitive device and forms a demand report. This method avoids the problem that the current and voltage acquisition is difficult to synchronize, and can greatly reduce the system cost and the amount of transmitted data. Because the terminals are calculated separately, the real-time performance of the monitoring system is improved.
Research on Key Technologies of High Voltage Power Cables in Smart Grid
Authors: Guo Yun , Xu Minhu , Shen Yubo , Cao Rong , Zhang Kexin , Zhao Xiangyu
Published: May 2021

The paper discusses important issues such as high-performance materials, electrical tree aging, space charge, insulation structure and technology, and cable operation detection in cable research and development. It is believed that DC cables will be used in power transmission for a long time in the future. It will receive more and more attention, but it is also facing the problems of insulation reliability and the development of new materials due to space charge and nonlinear temperature characteristics. The paper analyses the main reasons for the failure of power cables in the smart grid, and proposes several advanced power cable fault diagnosis technologies, and studies their principles and applications in order to improve the efficiency of fault diagnosis of the smart grid and protect the power grid. Operational reliability.
Single-phase Earth Fault Section Location Based on Differences’ Characteristics of Zero-sequence Currents in Distribution Network
Authors: Hu Xiuming , He Xudong , Xu Dan , An Yuqiong , Zhang Yi , Li Mei , Zhou Situo , Li Yuan , Huang Xiong
Published: May 2021

When a single phase earth fault occurs in distribution network, the difference between the transient zero-sequence currents at the head of the non-faulty section before the fault point is small, and the non-faulty section after the fault point also has this feature, but the difference between the zero-sequence currents at the head of the section before and after the fault point is big. Based on this, a method for comparing the single-phase grounding fault section location in distribution network based on the difference of the transient zero-sequence current was proposed. Based on the known distribution network structure, the fault section table was compiled, then the transient zero-sequence currents difference at the head of each section were compared, the fault section could be selected. The simulation by PSCAD/EMTDC verified the reliability of the method.
Research on Arc Trace of Switch on Load Breaking Based on LabVIEW
Authors: Su Jinzhou
Published: May 2021

In recent years, there are more and more electrical fire cases caused by the arc damage to the contact when the switch is breaking, so more attention is paid to the research of the arc trace when the switch is breaking with load. In this paper, starting from the analysis of switch breaking arc, the calculation method of three-phase and first open phase switch breaking arc is studied, and the arc trace test and analysis system is established based on LabVIEW. This system is used to test and study the distribution law of contact breaking arc trace of AC contactor under different opening phase angle, breaking current and breaking load test conditions, and the relationship between switch breaking arc trace and breaking area is given. Through the prototype test, a large number of test data are stored in the system database, which provides the test data and test basis for the design of high-performance switchgear, and also provides technical support for the real-time tracking, judgment and warning of product quality by using the historical data law in the operation process of low-voltage electrical circuit, so as to avoid causing electrical fire.
Research on Smart Mattress Based on Fiber Unbalanced Sagnac Loop
Authors: Ke Chenxi , Cai Yilun , Zhao Tao , Li Zhengying
Published: May 2021

Because the contact vital sign detection system is monitored through skin contact, it affects the user’s comfort and causes inconvenience. And most of the non-contact equipment is not high precision, or the cost is too high. To solve the above problems, this article is based on the physiological activity of slight vibration in multimode optical fiber micro bending deformation which result in the change of light intensity principle, considering the structure of the optical fiber Sagnac loop sensor has simple structure, low cost, but the signal to noise ratio is poor and is not sensitive to low frequency signal, this paper designed a based on intelligent mattress of non-equilibrium sagnac loop structure. The mattress can obtain the heart impact map signal in real time by changing the small light intensity, and obtain the heart rate, respiration rate and other information through the algorithm processing the signal. Mattress in the design of the sensing optical fiber module will be connected to two different types of optical fiber of Unbalanced Sagnac loop structure, solve the balance Sagnac loop structure of optical fiber access signal noise is bigger, poor sensitivity were weakness, go through the serpentine line way of embedded mattress, and using the mattress cover material for optical fiber micro bending cycle critical mechanical adjustment cycle, the mattress is of high sensibility. Cardiac and respiratory signals obtained in the laboratory were compared with those obtained from the balanced Sagnac loop, and through the fast Fourier transform (FFT) in frequency domain signal is analyzed, the vital signs of signal more clearly this mattress stable and less noise, change the tester for many times after tests, get the signal of high accuracy, the error is very small. The experiment shows that the mattress can realize the non-sensory vital signs signal detection, convenient for users to monitor their physical conditions in real time in daily work and life, and can timely notify the family members and medical staff in emergency, to avoid the occurrence of accidents.
Research on the Evaluation System of Battery Electric Vehicle Product Quality Satisfaction
Authors: Xu Wenxia , Liu Lu
Published: May 2021

The traditional fuel vehicle market has a relatively mature product quality evaluation system, which provides a scientific reference for consumer decision-making and enterprise’s research and design. However, the research on the product quality evaluation system of BEV (battery electric vehicle) on the market is still relatively preliminary. This paper first establishes a two-level BEV product quality satisfaction index system, then conducts a questionnaire survey of users in four typical scenarios: taxis, private vehicle, car-sharing and logistics vehicle, and finally uses SPSS and AMOS verifies the establishment of the satisfaction indicator in the four scenarios, and determines the weight in each scenario.
Research on Key Technologies of Power System Automation in Smart Grid
Authors: Tan Long , Zhang Kexin , Wei Chunming , Chen Shiyu
Published: May 2021

The paper summarizes the construction mode of distribution network automation system, and sorts out the operating characteristics of centralized intelligent mode and distributed intelligent mode. In view of the construction and operation of China’s distribution network automation system, point out common problems in system construction, operation and management in most regions. At the same time, the paper proposes the optimization of distribution network automation technology based on the gravity search algorithm, and improves the algorithm. Finally, the improved gravity search algorithm is applied to the IEEE 6-node power system. The calculation results show that the active power loss and voltage obtained by the algorithm are Compared with the original state, the level has been greatly improved, which greatly improves the automation efficiency of the power system. In this paper, the gravity search algorithm is used to calculate the optimization of power system automation technology, and the algorithm is improved, which overcomes the shortcoming of easy convergence to the local optimum.
Finite element optimization design of aircraft equipment installation structure
Authors: Su Jintao , Lou Jianping , Jiang Xiaolu
Published: May 2021

In this paper, the crack of the saggar was solved by finite element method, and the reason of the crack was found out through calculation and analysis. Then, the optimized design of the saggar was carried out, and the longitudinal stiffness of the saggar was strengthened, and the connection mode between the saggar and the saggar was changed. After calculating the optimized equipment support and sagger, it is found that the maximum stress of sagger is reduced by about 95% compared with that before optimization, which meets the requirements of strength design, indicating that the optimized scheme is very effective.
Response analysis of HTPB propellant under extreme high temperature conditions
Authors: Li TianPeng , Lu Bang , An ZhenTao
Published: May 2021

Temperature load is one of the loads that propellant grains are often subjected to. Temperature shock or temperature cycling will affect the structural integrity of propellant grains to a certain extent. How to ensure that the propellant grains meet the structural integrity requirements under temperature load conditions and ensure equipment the significance of a smooth launch is very important. In this paper, the HTPB propellant sample response analysis test is carried out based on the global temperature environment distribution of different temperature grades, and the extreme high temperature impact simulation experiment is carried out for the grains under the specific structure considering the impact of extreme high temperature conditions, and finally different models are constructed. The constitutive model of HTPB propellant under extreme high temperature, its grain meets the structural integrity criterion after being subjected to the impact of extreme high temperature.
Evaluation of Adjustable Load Potential of Industrial and Commercial Users Based on Power Demand Response
Authors: Liu Junhui , Yang Meng , Deng Fangzhao , Zhao Wenjie , Yang Qinchen , Li Hujun
Published: May 2021

In order to reduce the peak load in the period of power shortage through power demand side response, it is necessary to evaluate the peak cutting potential of major industries in this region. Based on electricity information acquisition system and big data mining analysis technology, this paper proposes a peak-clipping potential assessment method and process for power demand side response based on the characteristics of different industries, and evaluates and ranks the peak-clipping potential of 17 major industries in Henan Province. The evaluation method and results provide a theoretical basis for studying and judging the peak cutting scale and target in advance.
Experimental Research on Size Distribution of Suspended Particles in water Based on Mie Scattering Theory
Authors: Zhou Huan , Li Lian
Published: May 2021

With the rapid development of social economy, it has brought serious environmental pollution problems. This thesis mainly summarizes the measurement methods of particle size and distribution of suspended particles. We have analyzed the relationship between scattering coefficient and concentration of different wavelengths at each scattering angle; the relationship between scattering coefficient and concentration of different scattering angles at each wavelength; and the relationship between scattering coefficient and wavelength of different concentrations at each scattering angle. The result shows that particle size and distribution of suspended particles can be accurately reversed when scattering angle is 15 degree, denoising factor is 200 and wavelength range is 450 nm-500 nm. The analysis can effectively filter out suspended particles in water, which is essential to resolve air pollution and purify water quality.
Kinematics Analysis and Trajectory Planning of Dual-arm Pruning Robot
Authors: Lu Ye
Published: May 2021

In order to overcome the disadvantages of manual pruning of tree branches, the dual-arm pruning robot is proposed in this paper. The structure of the dual-arm pruning robot is designed, and the three-dimensional model is established. Taking the dual-arm of the pruning robot as the study object, the D-H method is used to build the kinematics model so as to better research the process of the two arms cooperative pruning. The kinematics simulation is done by Matlab to verify the rationality of the D-H parameters. The workspace of the dual-arm is analyzed, as well as the trajectory planning in joint space. The torques of each joint are solved to determine the power of the driving motor. The research results provide the theoretical basis for the final prototype manufacturing.
Research on Regenerative Braking Algorithm for New Energy Vehicles
Authors: Su Jintao , Lou Jianping , Jiang Xiaolu
Published: May 2021

This paper introduces the research status of regenerative braking abroad, expounds the typical regenerative braking algorithm, and introduces the overall structure of the integrated control algorithm of regenerative braking and stability. By comparing regenerative braking and ESP coordinated control algorithm, ABS and ESP coordinated control algorithm and dynamic coordinated control algorithm, the theoretical limitations, advantages and disadvantages of typical regenerative braking algorithm are discussed. It provides material for studying regenerative braking algorithm.
Review of the theory of hybrid modeling
Authors: Su Jintao , Lou Jianping , Jiang Xiaolu
Published: May 2021

This paper reviews the research theory of domestic and foreign hybrid modeling dynamic substructure and frequency response, and then introduces the basic principle of Jetmundsen, Ren substructure synthesis method, mechanical impedance admittance method, mechanical admittance method of interchange-ability and FBS substructure method. In the end, the scope and limitations of the method are compared and analyzed, and a new direction of hybrid modeling of dynamic substructure theory is put forward.
Study on equivalent method of solder joint of BIW
Authors: Su Jintao , Lou Jianping , Jiang Xiaolu
Published: May 2021

First create a simple beam model of finite element simulation analysis, find the principle and method of equivalent ACM solder joints, then the equivalent method of ACM welds a car white body finite element model is established, by using NASTRAN analysis modal, torsional rigidity and bending rigidity, and compared with the experiment on the mark, has the very good correlation. The results show that based on the 5mm×5mm mesh size, the equivalent ACM solder joint model is reasonable and reliable for the modal and static stiffness modeling analysis of BIW.
The Impact of New Investment on the Transmission and Distribution Price
Authors: Ma Tiannan , Du Ying , Jiao Jie , Wang Yun , Jian Yaling , Yu Guangxiu , He Puyu , Hu Guohui , Wu Guangchuan
Published: May 2021

The reform of transmission and distribution price is the core of power system reform. There are few studies on the impact of new investment on the transmission and distribution price. This paper discussesed the impact of new investment on the transmission and distribution price under different depreciation rate, asset liability ratio and new investment included in fixed asset rate. The results showed that the asset liability ratio does not have a significant impact on the electricity prices, while the change of the depreciation rate and the ratio of newly increased investment included in fixed assets will have a direct impact on electricity prices.
Research on consumer demand and trend of automobile HMI function
Authors: Wei Bing
Published: May 2021

Consumers pay more and more attention to automobile intelligence. Under the trend of “new four modernizations”, it is inevitable for automobiles to move towards intelligent terminals, and automobile HMI is an important carrier of automobile intelligence. At present, the design of automobile HMI is still not accurate enough to grasp the needs of consumers, which leads to poor consumer experience. In this paper, from the perspective of consumer demand, consumers are classified according to the difference of automobile HMI demand, and the experience evaluation and demand difference of different types of consumers on automobile HMI are analyzed to explore the demand trend of consumers on automobile HMI function.
Simulation Analysis of Ferro resonance of Generator-Transformer Group Shock Tripping
Authors: Zhang Dewen , Wei Xinyu , Yu Peiyong , Shen Yubo , Ma Haifeng
Published: May 2021

As a common self-excited oscillation in power systems, ferromagnetic resonance has a great threat to the insulation of electrical equipment due to overvoltage and overcurrent. The magnetizing inductance of electromagnetic voltage transformers has nonlinear characteristics, which tend to saturate the excitation and cause circuit resonance and generate resonance overvoltage. The ferromagnetic resonance overvoltage caused by the saturation of the transformer has greatly affected the safe and stable operation of the power grid. Therefore, it is very necessary to analyze, calculate and simulate the ferromagnetic resonance overvoltage, and to study the measures to eliminate resonance. Through theoretical calculation and simulation analysis of a hydroelectric power plant generator-transformer group reverse transmission impulse tripping fault, the cause of its ferromagnetic resonance was analysed, and relevant operation and maintenance suggestions were put forward to provide a basis for further research.
Application Analysis of Power System Control and Fault Diagnosis Based on Ant Colony Algorithm
Authors: Wu Linlin , Ren Hongchang , Li Dongyi
Published: May 2021

Due to the frequent occurrence of power system faults and the complexity of fault types, the speed of traditional control methods is slow, so a power system control method based on ant colony dispersion walk algorithm is proposed. Artificial neural network is a method and technology in machine learning, which has been widely used in engineering and technology. The problem of power system fault diagnosis is complex and changeable, so it is difficult to achieve accurate diagnosis by conventional methods. At present, the commonly used neural networks include perceptron, single-layer network, BP network and radial basis network, each of which has different characteristics and uses. BP network and radial basis network are commonly used in power system fault diagnosis. The network can be created, trained and simulated in MATLAB, and the power system fault model can also be established and simulated. According to the characteristics of the system nodes, a nonlinear control model composed of a set of differential-algebraic equations is established to establish the steady-state model of the power system structure, and the ant walk algorithm is used to solve the model and analyze the node information of the power system. The control output principle of power system power node is set to judge whether the operation state of power system is normal or not, so as to complete the design of power system control method based on ant colony dispersion walk algorithm. The experimental results show that the proposed method has fast control speed for power system faults. The synchronous frequency signal and voltage signal provided by the power system are extracted, the characteristics of the power system signal are classified, and the hidden fault location is determined by the time-frequency characteristic of the power system voltage signal. The experimental results verify the robustness of the above methods for fast hidden fault location.
A Distributed Optimization Algorithm for Multi-Area Power Grid Transmission Congestion Management
Authors: Ji Yuejin , Liu Kai , Li Xianshang , Zhang Gaofeng
Published: May 2021

The interconnection of power grid brings significant economic benefits, while it calls for higher requirements to the security, stability and economic operation of power system as well. With high dimensionality of its optimization problem, the whole network centralized optimal power flow (OPF) algorithm is computational inefficient. Therefore, on the basis of power grid layering and zoning, the distributed optimal power flow calculation method in interconnected power grid with multiple control centers has important realistic significance. A distributed optimization algorithm of interconnected power grid transmission congestion management is proposed in this paper. The active power constraints of inter-area transmission interfaces are considered to satisfy the trade power constraints between adjacent sub-systems. The coordination and cooperation procedure counts on the correction and updating of boundary bus equivalent injection power and voltage vector. The numerical results on IEEE test systems show that the algorithm for transmission congestion has good convergence ability.
Research on Power Equipment Fault Diagnosis Technology Based on Acoustic Signal
Authors: Zou Hongsen , Chen Haoyang , Liu Zhiyuan , Wang Guohua
Published: May 2021

In recent years, with the continuous growth of China’s electricity load, the power industry has developed rapidly. Power transformer is the most important and expensive in transmission and distribution system of large-scale power equipment, which undertakes the important task of power transmission. With the development of power system towards ultra-high voltage, large power grid and intelligence, it is particularly important to improve the safe operation level of transformers. Once the power transformer accident occurs, the repair time is longer and the influence is more serious. To solve this problem, a new power equipment fault diagnosis technology based on acoustic signals is studied in this paper, which is used to accurately diagnose and analyse the running state of the transformer. The simulation results show that the fault diagnosis based on acoustic signal is more accurate and can effectively diagnose the fault of power equipment.
Fast Energy Equivalent Modeling of MMC Based on Controlled Source
Authors: Li Jiyu , Chen Xue , Chen Dacai , Ye Xiangman , Guo Jintao , Cheng Zhiwei
Published: May 2021

The electromagnetic transient simulation of large-scale MMC has the problems of large memory requirements and long simulation time, which restricts the development of simulation research [1-3]. To solve the problem of low efficiency of MMC electromagnetic transient simulation, this paper proposes a fast energy equivalent model for the equivalent of MMC. Thus, the fast simulation of MMC under normal working conditions and efficiency of simulation model can be realized. First of all, the rationality of achieving the Norton equivalent of MMC bridge arms is derived from the node voltage analysis method. Then the equivalent modeling method of MMC controlled source can be obtained. On this basis, a fast energy equivalent model that can simulate the capacitance characteristics of each sub-module of MMC is proposed by analyzing the switching function form of MMC. Finally, the proposed simulation modeling method was verified on the PSCAD/EMTDC simulation platform.
Method for Suppressing AC Side Fault Feed Current of Flexible DC Distribution Network Based on Improved Bidirectional Thyristor
Authors: Gao Chao , Chen Xianda , Li Jiyu , Zhao Guosheng , Liu Jianwei , Lin Yufeng
Published: May 2021

In the flexible DC power distribution system, once the DC side fails, the converter’s interior will be quickly affected by the AC side fault feed. In view of the shortcomings of the current fault feed suppression methods, an improved AC side fault feed suppression method based on the improved bidirectional thyristor is proposed. The simulation results show that the above method can suppress the impact of the feed current inside the AC side converter and limit the short-circuit current flowing into the bidirectional thyristor on the AC side.
Research on The Hidden Dangers and Countermeasures of Electricity Safety in College Students’ Apartments
Authors: Zhang Benchang , Zhang Fengyan , Tang Wei
Published: May 2021

Students’ apartments in Colleges and universities are densely populated, which is a high incidence area of campus fire. There are many hidden dangers of electrical safety in student apartments. In terms of buildings, the infrastructure construction is not standardized, the overall function design does not match, the power supply and distribution lines and safety facilities cannot meet the current needs of life, the power lines are aging, the insulation layer is damaged, and so on. In terms of power consumption, high-power electrical appliances are used in violation of regulations and requirements. The reasons for the above safety risks are: the school management personnel have weak safety awareness, do not pay enough attention to the safety management of electricity, the quality of some electrical equipment is not up to standard, the hidden danger investigation and rectification is not strict, and so on. The main countermeasures are: the school should fulfill the main responsibility of safety work, strengthen the apartment safety management, strengthen the students’ awareness of electrical safety, popularize the knowledge of electrical safety, investigate and rectify the hidden dangers of electrical safety, etc.
Research on European capacity cost recovery mechanism and its experience to China’s power market construction
Authors: Xing Yuhui , Zhang Maolin , Liu Xiangrui , Chen Qinggui , Mu Chunfeng , Wang Bangcan
Published: May 2021

This paper makes an in-depth study of generation capacity cost recovery issues that have been, or are being faced, in European countries and summarizes its experience to China during the construction of competitive power markets. Firstly, the paper explains the idea and principle of capacity cost recovery mechanisms in EU, which are policy instruments to ensure adequate investment in generation capacity, then analyses the obstacles to the realization of capacity cost recovery in the energy-only market. Then, the paper divides the European capacity cost recovery mechanism into five categories: strategic reserve, capacity obligation, capacity auction, reliability option and capacity payment, and expounds the operation flow of the mechanisms respectively in detail. Thirdly, the paper studies the possible impact of the capacity cost recovery mechanism on the electricity market. Finally, the paper summarizes the practical experience of European capacity cost recovery mechanisms and lay a foundation for the design of generation capacity cost recovery mechanism in China.
Modeling and Analysis of Heat transfer of Resolder Furnace based on Thermodynamics
Authors: Liu Yunge
Published: May 2021

In the production process, the printed circuit board with all kinds of electronic components is placed in the rewelding furnace and the electronic components are automatically welded to the circuit board by heating. In this production process, the temperature control of the resolder furnace is very important to ensure the product quality. In this paper, by analyzing the heat transfer characteristics of rewelding furnace, the three-dimensional problem is transformed into one-dimensional problem, and the transient heat transfer process is studied and analyzed. Considering the two heat transfer modes of heat conduction and heat convection, the partial differential equation model of one-dimensional double-layer heat conduction is constructed, and the classical mathematical and physical method is used to model and simulate the heat conduction in the welding process of printed circuit board. the variation diagram of the furnace temperature curve and the temperature in the center of the welding zone at different positions in the small temperature zone are obtained.
Improved Method of Pasting and Fixing Metal Conduit Heating Tape
Authors: He Yun , Du Ruizhao , Zhang Qiang
Published: May 2021

In the development process of my country’s spacecraft, the heating of the working medium in the metal conduit primarily adopts the method of winding a heating tape on the outer wall of the metal conduit. Silicone rubber is usually used as the filling medium to reach good heat transfer between the heating tape and the metal conduit. The heating tape winding and fixing method of the cotton thread used at this stage has disadvantages such as time-consuming, labor-intensive, and low work efficiency. Based on the experience of the spacecraft’s final assembly, a method of winding and fixing the heating tape with a fixing clip is proposed in this paper. This method is simple and convenient, improving the efficiency of pasting and winding the heating tape of the metal conduit.
Research on a New Type of Electronic Audio Communication system
Authors: Wang Guimin , Wang Linfeng , Wang Zihao
Published: May 2021

Bluetooth technology realizes the wireless data transmission between modern communication equipment and the Internet, which greatly improves the efficiency of office and communication. This research is based on matlab/simulink as the development platform to realize the simulation of Bluetooth voice transmission system. The system is composed of master transmitter, slave receiver and transmission, interference, signal source, error table and signal display unit. through simulation, the frequency spectrum of frequency hopping signal, Bluetooth signal, 802.11 and slotting signal time domain diagram are obtained. The system improves students’ understanding and design ability of data wireless transmission technology.
Evaluation of Intelligent Air Defense algorithm based on Machine Learning
Authors: Guo Jiayuan , Zhao Zirui , Zhou Jinghao
Published: May 2021

In the complex and rapidly changing combat environment, the enemy interference and sensor performance limitations and other factors lead to insufficient battlefield information. In order to make the UAV have the ability to carry out threat assessment under the condition of insufficient information, a Bayesian network (BN) threat assessment modeling method based on small data sets is proposed in this paper. Starting with the two problems of BN structure learning and parameter learning under the condition of small data set, using the constraint matrix obtained by Bootstrap method as the constraint item added to the score function, a BN structure learning algorithm based on small data set is proposed, and the BN parameter learning algorithm based on interval prior constraint is adopted. The simulation results show that, compared with the traditional BN learning algorithm, the BN learning algorithm proposed in this paper has higher accuracy and availability in UAV threat assessment modeling under the condition of small data set.
Physical modeling of rocks on the basis of rock–gas–moisture composites
Authors: Kurlenya MV , Rostovtsev VI , Kulagin RA , Kulagin OR , Sivolap BB
Published: May 2021

The issues of obtaining and investigating composites consisting of coal and rock solid particles, gases (methane, hydrogen) and moisture, as well as approaches to mechanisms initiating catastrophic dynamic phenomena in mining are discussed. On the samples of different materials (coal, limestone, graphite, etc.) using the developed test bench, the dependences of physico-mechanical properties of cores on pressure are established. For longflame coal of various size, the features are shown for changing the temperature of briquette mass in increasing pressure up to 200 MPa. The composites imitating natural coal and other rocks are created.
Development of static and kinematic approaches in geomechanical problems
Authors: Mirenkov VE
Published: May 2021

The hypothesis of a linear stress field of a rock mass undisturbed by driving workings underlies the solution to many problems of rock mechanics. The problem of rock pressure control requires knowledge of the stress-strain state of the rock mass in the vicinity of workings, which causes the development of analytical and numerical methods for calculating the deformation. When the methods of numerical calculation were not sufficiently developed, the analytical capabilities of the selection of stress functions were used, which satisfied the conditions of small strain elasticity theory. The greatest success in this direction was achieved for the areas with angular points. The development of numerical methods shifted the point of influence of investigations to calculating the deformation of specific cases arising in a rock mass with workings. It is established in the work that analytical solutions for the areas with angular points are incorrect, and numerical solutions of Cauchy problems are also incorrect if an additional problem is not considered.
Solution of three basic problems of elasticity for half-plane
Authors: Mirenkov VE
Published: May 2021

Solution of elastic problem for half-plane is of the highest concern in almost every field of engineering. However, there are no relations binding the values of all components of the stress-strain state at the half-plane boundary This paper shows that arbitrary formulation of the boundary conditions considerably simplifies integral equations and transfers them to the class of Fredholm’s first kind equations. Considering symmetry, the problem for half-plane with mathematical cut is reduced to the problem on half-plane boundary. Regardless of the method, any solution is reduced to ill-posed problem.
Development of experimental plant for investigation of coal adsorptive capacity using methane
Authors: Rybalkin LA , Shilova TV
Published: May 2021

A thermostatic plant for studying the adsorptive capacity and permeability of coal core was developed. The plant design allows to saturate coal with methane and to filter gas at various values of axial and lateral compression of the sample. The use of an automated system for recording differential pressure and gas volumes in the inlet and outlet tanks eliminates the need for manual control, which is especially important during long-term testing of low-permeable coals.
Analysis of coal seam degassing efficiency using boreholes and hydraulic fracturing
Authors: Serdyukov SV , Kurlenya MV
Published: May 2021

The effect produced by hydraulic fracturing on the filtration resistance of coal seam zone subject to drainage by parallel boreholes is considered. The resistances to the gas inflow depending on the orientation of fractures, thickness of seam, and distance between the boreholes are analyzed. The efficiency of single and multistage hydraulic fracturing in forming multiple transverse and main longitudinal cracks is compared.
New methods for signal digital processing to determine the parameters of seismic wave propagation models
Authors: Serdyukov AS , Yablokov AV , Chernyshov GS
Published: May 2021

The methods based on the use of time-frequency representations are proposed. The useful signal is reconstructed from the amplitude peaks of time-frequency spectrograms obtained by S-transform. As a result of numerical experiments, it is shown that using narrow time-frequency intervals (about 10–20 time reports), it is possible to determine the parameters of a pulsed-type signal with substantially longer duration.
Effect of confining pressure on pendulum wave spectra recoded in block media under seismic loading
Authors: Sher EN , Chernikov AG
Published: May 2021

Effect of external compression on seismic waves in rock mass was tested on one-dimensional models of block media subjected to impulsive loading. It is shown that a low-frequency pendulum wave appears at the shock wave head as a result of dispersion. The pendulum wave parameters are governed by the mass of blocks and by the yielding properties of block interfaces. External compression increases stiffness of block interfaces, which leads to an increase of the wave velocities and to a change of the wave spectra. The model experiments tested the possibility of external compression assessment from the parameters of pendulum wave spectra.
Features of seismic wave travel along a coal pit wall
Authors: Yushkin VF
Published: May 2021

Triple gain of the maximum amplitudes or massif vibrations in a final phase of the consecutive blasting of groups of borehole charges during the propagation of a seismic blast wave outside the mined block in the Quarternary deposits of a coal mine slope has been experimentally established. The effect of “rocking” the massif occurs stepwise, and it is synchronized according to the selected delay intervals at detonation.
A method for calculating loads on roof support in mines
Authors: Seryakov VM
Published: May 2021

The author proposes an approach to the stress–strain analysis of mine support with regard to all displacements of the stope boundary until it makes contact with the support using the stiffness matrix of intact rock mass. Modeling of the void formation and of the joint deformation of the support and adjacent rock mass uses iterative procedures from the methods of initial stresses and initial strains. The support load algorithm and software package are developed.
Assessment of natural horizontal stresses and deformation characteristics of load-bearing elements in room-and-pillar mining by inverse problem solution using mine survey data
Authors: Panov AV , Miroshnichenko NA
Published: May 2021

The authors discuss assessment of deformation characteristics of load-bearing elements in room-and-pillar mining system and natural horizontal stresses. This method is based on solution of mixed-type inverse problems using a two-dimensional elastic model. Numerical calculations for a typical mine geometry using synthetic input data (relative displacements of mine void boundary points, recorded using mine survey techniques) have found the required data amount sufficient to ensure unambiguous solvability of inverse problem.
Safe and ecological performance of mining and processing industry
Authors: Kovalenko KA
Published: May 2021

Mineral mining and processing activities result in highly toxic arsenic-bearing waste water discharged in natural water bodies. The promising methods of arsenic removal from waste water use adsorption at natural sorbents and oxidizers. The tests of arsenic removal by adsorption at magnesium- and manganese-bearing minerals show that the use of these natural raw materials can greatly enhance efficiency of the environmental activities in the mining and processing industry.
Test bench to study drying of geomaterials in vibratory conveying
Authors: Kulikova EG , Dudina AM
Published: May 2021

The authors review vibrating machines used to convey and dry different geomaterials. The article describes the structural layout of a vibrating device with an elastic operating component designed at the Institute of Mining, SB RAS for the simultaneous conveying and drying of loose materials. The experimental test bench is applicable to studying influence of dynamic parameters of the elastic conveying component on the efficiency of drying of granular materials.
Justification of layout diagrams hydraulic percussion mechanisms by the comparative analysis of dynamic parameters
Authors: Cheshchin DO , Rechkin AA , Danilov BB
Published: May 2021

The simulation models are used to compare achievable dynamic parameters of layout diagrams of hydraulic percussion mechanisms having similar size and weight. The comparison results prove application feasibility of these layouts in engineering hydraulically driven percussion machines. The optimization methods are used to find the optimal values of design variables to meet the criterion of maximal blow energy.
The force on the drill tool in puncture and ramming in soil
Authors: Danilov BB , Cheshchin DO
Published: May 2021

The authors compare the technological capabilities of puncture, ramming and their combination in horizontal hole-making in soil. The test data on the hole-making tool–soil interaction are presented for the three methods. It is efficient to combine these methods to enhance performance of hole-making.
Physical modeling of ring-shaped elastic valve operation in hydraulic percussion mechanism
Authors: Plokhikh VV , Danilov BB
Published: May 2021

The paper proves usability of elastic lock-and-control valves in hydraulic percussion mechanisms. The requirements imposed on positive-displacement impact machines for rock drilling are substantiated. The dedicated test bench for determination of actuation conditions of the elastic valve is described. The experimentation procedure, sequence and data are presented.
Tensile strength test and fracture toughness test of cores with axial hole
Authors: Efimov VP
Published: May 2021

This studies approves the the tensile stress tests of rock specimens with axial holes of different diameters under loading along the diameter. The test results are presented for core specimens of rocks and some equivalent materials. The test data are processed using the criterion of fracture gradient and the integral criterion of fracture. The values of tensile strength and fracture toughness obtained using this approach and by the standard technique are compared.