bluuebunny/crossref_metadata_2025 huggingface dataset:
The bifurcation set as a topological invariant for one-dimensional dynamics
Authors: Fuhrmann Gabriel , Gröger Maik , Passeggi Alejandro
Published: March 2021

For a continuous map on the unit interval or circle, we define the bifurcation set to be the collection of those interval holes whose surviving set is sensitive to arbitrarily small changes of (some of) their endpoints. By assuming a global perspective and focusing on the geometric and topological properties of this collection rather than the surviving sets of individual holes, we obtain a novel topological invariant for one-dimensional dynamics. We provide a detailed description of this invariant in the realm of transitive maps and observe that it carries fundamental dynamical information. In particular, for transitive non-minimal piecewise monotone maps, the bifurcation set encodes the topological entropy and strongly depends on the behavior of the critical points.
Traveling fronts in dissipative granular chains and nonlinear lattices
Authors: James Guillaume
Published: March 2021

We consider an infinite chain of particles with nonlinear elastic and dissipative nearest neighbors interactions. Assuming the existence of a traveling front between uniformly compressed (or stretched) states, we obtain jump conditions relating the wave speed and limiting particle velocities to the relative displacements at infinity. Using this result, we characterise compression fronts in chains of touching beads, for viscoelastic contact laws that include a nonlinear elastic force (generalised Hertz contact) and viscous dissipation. We compute compression fronts numerically for the generalised Kuwabara–Kono model in which the viscous contact force is proportional to the derivative of the elastic force, without precompression of the chain. Steady fronts are obtained both as the end result of the compression of one end of the chain and using a shooting method which provides numerically exact traveling waves. Depending on the magnitudes of contact damping and strain applied downstream, we obtain either overdamped (monotonic) or underdamped (oscillatory) compression fronts. To explain this transition and approximate the front profiles, we consider a continuum limit valid when the exponent of the contact nonlinearity is close to (and above) unity. Using multiscale expansions, we formally derive two different amplitude equations for long waves, a Burgers equation with logarithmic nonlinearity, and a logarithmic Korteweg–de Vries (KdV)–Burgers equation for small contact damping. Both models possess traveling front solutions that are in good agreement with the front profiles computed numerically in the granular chain. The analysis of the logarithmic KdV–Burgers equation allows one to approximate the critical damping corresponding to the transition from underdamped to overdamped fronts.
The relevance of whole or segmental body bioelectrical impedance phase angle and physical performance in adolescent athletes
Authors: Obayashi Hiromune , Ikuta Yasunari , Fujishita Hironori , Fukuhara Koki , Sakamitsu Tetsuhiko , Ushio Kai , Kimura Hiroaki , Adachi Nobuo
Published: March 2021

Objective. The physical condition of athletes can be assessed easily and quantitatively using objective indicators. Bioelectrical impedance measures the phase angle (PA), representing hydration and cell function, and is a potential clinical indicator of physical condition. This study aimed to investigate the association between PA and physical performance in adolescent athletes. Approach. Overall, 170 adolescent athletes underwent a sports medical check-up, including body composition measurements and physical performance tests. Whole-body and segmental PAs (arm and leg) were determined based on body composition values. Isometric grip power and knee isokinetic muscle strength were measured as parameters of muscle strength. Counter movement jump height and squat jump height were measured as jump parameters. Associations between PA and each muscle strength or jump parameters were analysed using Pearson product-moment correlation coefficient or Spearman’s rank correlation coefficient. Main results. Whole-body and upper limb PAs were highly correlated with grip power (r = 0.70–0.80). Whole-body and lower limb PAs were correlated with knee isokinetic muscle strength (r = 0.43–0.59). Whole and all segmental PAs were correlated with counter movement jump height (r = 0.46–0.57) and squat jump height (r = 0.42–0.52). Significance. PA can be used to monitor physical condition and sports performance in adolescent athletes. Segmental PAs can help assess the condition of the corresponding body part.
Sound modes in collisional superfluid Bose gases
Authors: Furutani K , Tononi A , Salasnich L
Published: March 2021

We theoretically investigate sound modes in a weakly-interacting collisional Bose gas in D dimensions. Using the Landau’s two-fluid hydrodynamics and working within the Bogoliubov theory, we observe the hybridization of the first and second sound modes for D ⩾ 2. To model the recent measurements of the sound velocities in 2D, obtained in the weakly-interacting regime and around the Berezinskii–Kosterlitz–Thouless transition temperature, we derive a refined calculation of the superfluid density, finding a fair agreement with the experiment. In the 1D case, for which experimental results are currently unavailable, we find no hybridization, triggering the necessity of future investigations. Our analysis provides a systematic understanding of sound propagation in a collisional weakly-interacting Bose gas in D dimensions.
Insight into the chemomechanical coupling mechanism of kinesin molecular motors
Authors: Xie Ping
Published: March 2021

Kinesin is a two-headed biological molecular motor that can walk processively on microtubule via consumption of ATP molecules. The central issue for the molecular motor is how the chemical energy released from ATP hydrolysis is converted to the kinetic energy of the mechanical motion, namely the mechanism of chemomechanical coupling. To address the issue, diverse experimental methods have been employed and a lot of models have been proposed. This review focuses on the proposed models as well as the qualitative and quantitative comparisons between the results derived from the models and those from the structural, biochemical and single-molecule experimental studies.
Evaluation of silicon carbide as a divertor armor material in DIII-D H-mode discharges
Authors: Abrams T. , Bringuier S. , Thomas D.M. , Sinclair G. , Gonderman S. , Holland L. , Rudakov D.L. , Wilcox R.S. , Unterberg E.A. , Scotti F.
Published: March 2021

Silicon carbide (SiC) represents a promising but largely untested plasma-facing material (PFM) for next-step fusion devices. In this work, an analytic mixed-material erosion model is developed by calculating the physical (via SDTrimSP) and chemical (via empirical scalings) sputtering yield from SiC, Si, and C. The Si content in the near-surface SiC layer is predicted to increase during D plasma bombardment due to more efficient physical and chemical sputtering of C relative to Si. Silicon erosion from SiC thereby occurs primarily from sputtering of the enriched Si layer, rather than directly from the SiC itself. SiC coatings on ATJ graphite, manufactured via chemical vapor deposition, were exposed to repeated H-mode plasma discharges in the DIII-D tokamak to test this model. The qualitative trends from analytic modeling are reproduced by the experimental measurements, obtained via spectroscopic inference using the S/XB method. Quantitatively the model slightly under-predicts measured erosion rates, which is attributed to uncertainties in the ion impact angle distribution, as well as the effect of edge-localized modes. After exposure, minimal changes to the macroscopic or microscopic surface morphology of the SiC coatings were observed. Compositional analysis reveals Si enrichment of about 10%, in line with expectations from the erosion model. Extrapolating to a DEMO-type device, an order-of-magnitude decrease in impurity sourcing, and up to a factor of 2 decrease in impurity radiation, is expected with SiC walls, relative to graphite, if low C plasma impurity content can be achieved. These favorable erosion properties motivate further investigations of SiC as a low-Z, non-metallic PFM.
Analysis of Otha-Kawasaki Free Energy by Means of the Brazovskii Approach
Authors: Pezzutti A D , Hernández H
Published: March 2021

In this work, we developed the expansion of the Brazovskii type of Otha-Kawasaki free energy used in different condensed matter systems. This expansion makes it easy to evaluate the contributions of the terms of energy involved, usually referred to as short-range “double-well” potential and long-range. Thus, there is a powerful tool to explore and understand the dynamics of systems evolution out of equilibrium.
Study on High Temperature Oxidation Properties of Molybdenum-based Alloys
Authors: Bao Ziming , Han Renheng , Zhu Yanqing , Li Ning , Zhang Chi , Zhao Chengzhi , Zhang Hexin
Published: March 2021

Research and design of different components of molybdenum-cobalt alloy, including Mo-3Co alloy, Mo-6Co alloy, Mo-9Co alloy and pure molybdenum alloy. The weight loss of pure molybdenum alloy, Mo-3Co alloy, Mo-6 Co alloy and Mo-9Co alloy at 400 °C, 600 °C, 800 °C, 1000 °C after 1-hour oxidation was systematically analyzed. Observing the surface of the oxide layer, it was found that the Mo-6Co alloy was vigorously oxidized at 800 °C and 1000 °C to form volatile MoO3. As the cobalt content increased, the weight loss rate of the samples showed a downward trend at different oxidation temperatures. Granular oxides were formed when the Mo-6Co alloy sample was oxidized at 400 °C; when oxidized at 600 °C, scaly oxides were formed; when oxidized at 800 °C and 1000 °C, blocky or flaky oxides were formed. Addition of the element of cobalt can obviously alleviate the oxidation of molybdenum-based alloy specimens at high temperature.
Antecedents of continuance intention in e-campus system: The moderating effect of internet experience
Authors: Razak Fahmi Zaidi Abdul , Kasim Nur Muneerah Binti , Harun Siti Aminah Binti , Sulaiman Noor Suhani
Published: March 2021

This study applies internet experience as a moderator to investigate how the relationship between satisfaction and continuance intention is differ based on user experience. Analysis of 315 usable responses shows that internet experience plays a significant role in moderate the relationship. This empirical study employ quantitative survey as a research design. The data were analysed using the statistical package for data analysis SPSS 22 for Windows. This paper concludes with implications and limitations of the study.
The Relationship between Core Strength Performance with Sprint Acceleration
Authors: Afandi Mohamed Azizul Mohamed , Mohamad Nur Ikhwan , Fazila Nor , Malek Abd , Chinnasee Chamnan , Md Nadzalan Ali
Published: March 2021

The objectives of this study were to determine the relationship between average core strength and sprint acceleration performance. Besides that, this study also intended to determine the relationship between body height and body weight with average core strength and sprint acceleration performance. Sixty-three male sport science students (height 1.67 ± 0.07 m; body mass 63.25 ± 13.90 kg) from variety of sport background participated in this study. To test the relationship, core strength (7-stage abdominal strength test and prone-bridge test) and sprint acceleration (35-m sprint test) performance was measured and a Pearson’s correlation coefficient was used to analyse the results. Sprint was found to be significantly correlated with prone bridge performance, r (63) = -0.43, p = 0.00). The relationship between body height with sprint performance stated significant relationship (r (63) = -0.48, p = 0.00) and body weight with 7-stage abdominal strength values reveal a significant relationship (r (63) = - 0.28, p = 0.03). In conclusion, this finding has suggested an optimum core strength may influences sprint acceleration performance which would give greater advantages in order to improve physical performance or optimize sport performance.
Reliability and Validity of Badminton Special Speed Training Method toward Success Score and Time Perception Predictive Skills Performance of Badminton Players
Authors: Guo Su Zhan , Mohamad Nur Ikhwan , Zakaria Jaffry , Yu Lin , Malek Nor Fazila Abd
Published: March 2021

The aim of this study was to examine the validity and reliability of badminton special speed training method (BSSTM) test instrument on success score and time perception predictive skills performance among elite badminton players. Thirty elite badminton players had participated for the purpose of this study. Expert’s evaluation with content validity analysis were used to determine validity. Test-retest method were used to determine the reliability of the success score and the time perception predicting skill performance of badminton players. The BSSTM scoring sheets which consisted of three parts of assessment scoring methods (Part A, B and C) were evaluated part by part by experts. Participants also performed two separated yet similar testing sessions where the BSSTM scoring methods sheets used to evaluate their performance. Results of the analysis indicated high content validity for all Part A, B and C (α = .963, α = .956, α = 956 respectively) with high reliability also recorded (r = .953, r= .986, r= .974 respectively). In conclusion, the BSSTM and its scoring instruments is valid for badminton specific speed performance tests and reliable to be used. Badminton coaches and players may utilized BSSTM as a training method and performance monitoring tools in their periodized training program.
Implication of human skin temperature under high humidity to the construction workers’ by using computational thermal simulation
Authors: Ismail Ahmad Rasdan , Jusoh Norfadzilah , Makhtar Nor Kamilah , Zein Raemy Md , Rahman Ismail Abdul , Khamis Nor Kamaliana , Mohamad Darliana
Published: March 2021

Workers in construction are the most in danger to the poor health effects of heat exposure every day. A simulated lifting task based on computational thermal model of the workers in the construction is designed and utilized to study the distribution of skin temperature under two different temperatures (32°C and 25°C) and statics relative humidity at 70%. The thermal distribution and simulation for the temperature towards human/manikin body was designed by utilising ANSYS Simulation software. The Computational Fluid Dynamics (CFD) simulation revealed the detailed analysis of the thermal distribution around the body/manikin while conducting lifting activities. The CFD also indicated that case study (32 °C/70%) provided the significant physiological effect to the workers in the construction. The mean skin temperature in this case study is 34.7 °C. The heat index shows that when the human working in a hot climate, they had received significantly heat as high as the heat generated from their surrounding. This experiment concluded that skin temperature was influenced significantly by the tropical climate. This particular study provided potential exploration of the environment heat to the construction workers in Malaysia through the prediction of skin temperature.
A New De-Noising Method for Ground Penetrating Radar Signal
Authors: Ma YongMin , Jong YongGwang , Liu Yang
Published: March 2021

The de-noising of data has become the key problem of ground penetrating radar (GPR) research. In this paper, the de-noising method based on combination of complete ensemble empirical mode decomposition (CEEMD) and wavelet decomposition is proposed. By combining CEEMD and wavelet decomposition, the effective signal information can be extracted from the removed intrinsic mode function (IMF) components in de-noising based on CEEMD. Numerical simulation results show that the quality of the GPR signal can be obviously improved by using the combination method.
Research on Energy Efficiency Application of Wireless Communication Energy Saving and Emission Reduction Based on Self-organizing Network Game Technology
Authors: Bai Sijun , Zou Tao , Rong Xibai
Published: March 2021

Energy efficiency is a very important performance index in wireless ad hoc networks. So far, there is no universally accepted definition of the energy efficiency of self-organizing networks, and most of the conclusions drawn are asymptotic or qualitative, and its practicality is very limited. Aiming at this problem, a trust model based on game theory is proposed. The model introduces a time decay function to improve the accuracy and dynamic adaptability of trust evaluation, and introduces a node transaction density function in the recommendation trust calculation to calculate the recommendation performance of the recommended node. Reliability: In order to effectively encourage nodes to actively provide high-quality services and punish bad behaviour nodes, game theory is also introduced to analyse the trust value of nodes and decide whether to forward messages according to the analysis results. The simulation results show that the algorithm can adaptively deploy network nodes according to the distribution of task requirements, and quickly achieve the optimal layout.
Optimization Model Design for Temperature Curve of Reflow Furnace
Authors: Luo Xindi , Wang Zeshu , Deng Wenhao
Published: March 2021

How to adjust the temperature zone temperature and furnace speed parameters to optimize the furnace temperature curve, so as to improve the product quality is the main problem faced by the temperature curve optimization of the reflow furnace. In this paper, the heat transfer model is established by the heat convection and heat conduction equations, and the mechanism of temperature change in the welding area is analyzed. Then, by gradually determining the objective function and comprehensively establishing the optimization model according to the known conditions, the optimal parameters are solved, so as to solve the optimization problem of furnace temperature curve. According to Newton’s cooling law, specific heat theorem and Laplace equation, the temperature function of the center of the welding zone is deduced and solved, and the analytic function model of the temperature change in the center of the welding area can be obtained by synthesizing the inherent size conditions of the reflow furnace. Taking the corresponding data of experimental temperature and time as the fitting data, the undetermined parameters of the model were solved by nonlinear least square fitting method and undetermined coefficient method. The square sum of fitting residuals is 5857.7, which proves that the model has good fitting effect. Using the new experimental data to solve the model, the temperature change of the welding center at each position and time in the reflow furnace is analyzed. The temperature in the center of the welding area at the middle point of the low temperature zone 3, 6, 7 and the end of the small temperature zone 8 is 143.81°C, 181.78°C, 201.33°C, 228.97°C, respectively.
Research on Optimization of Sea Rice Biscuit Based on BP Neural Network
Authors: Han Rui , Wu Juxian , Shi Xiaoyan , Li Mingjun , Ye Shengquan
Published: March 2021

Sea rice is rich in dietary fiber and selenium, and has the characteristics of low fat and low calories. The main raw material of this paper is sea rice noodles. The sensory evaluation, chewiness and hardness of functional biscuits are the main inspection criteria. Through orthogonal experiments and the use of BP neural network modeling and prediction, the relationship between the three influencing factors of the model and sensory evaluation indicators Carry out modeling and predictive analysis to guide the optimization research of product formula and improve efficiency. The difference between the three predicted values and the actual indicators is small, which are - 0.0073%, -0.0091%, and 0.3225%, respectively, which have a good prediction effect.
The Wind Vibration Analysis of High-rise Isolated Structures Based on Linear Regression Filter Method
Authors: Wang Yong Hua , Yang Zhen
Published: March 2021

Vibration isolation is a fast developing structure vibration control technology.Due to its simplicity and effectiveness,it has been gradually applied to high-rise buildings in recent years,and high-rise isolated structures have a large effect of high-order vibration damping.Compared with high-rise aseismic structures,the period of high-rise isolated structures is larger,so the wind load effect is larger than that of high-rise aseismic structures.This paper on the damping effect analysis of structures under seismic action,to verify the rationality of the design of vibration isolation,and then by now a mature linear regression filter method to simulate the fluctuating wind,with the average wind speed into wind pressure time history input of high-level structure,to analyze the effect of structure under wind load,in the analysis of the structure of the base shear and top acceleration as investigation object,focus on the guarantee structure has a certain effect of shock absorption effect of wind vibration and its control.
Experimental study on compound phase change materials
Authors: Li Sasa , Xu Hong , Wang Wenhao
Published: March 2021

According to incomplete statistics, the mine heat damage accidents since the 1970s have threatened the safety of mining and the safety and health of underground workers all the time. At present, many mine workers have physical discomfort in high-temperature mines, and then affect the safe mining of mines. As China’s shallow coal seam has been basically mined out and gradually mined to deep mines, the underground heat damage is becoming more and more serious. The overall and local cooling of the mine has become a difficult problem in the underground work, which also restricts the production of the mine. The development of individual cooling equipment can effectively alleviate the heat stress of mine workers. Therefore, it is necessary to select non-toxic environmental protection and low-cost cooling materials as the cooling medium of cooling clothing. It is necessary to consider that the cooling medium is harmless to human body and can keep the human body working in a more comfortable micro environment without affecting the working efficiency.
Research on Vibration Characteristics of Propulsion Shafting Under Unbalanced-misaligned Coupling Fault
Authors: Xu Kai , Zhang Yuqing , Ming Tingfeng
Published: March 2021

Vibration characteristics under unbalanced-misaligned coupling fault of propeller shaft were studied. Firstly, the rigid-flexible mixing model of propeller shaft system test bench is established by using Solidworks and ADAMS. Then, the shafting vibration characteristics in time and frequency domain are obtained by simulation analysis under normal, unbalanced, misaligned and unbalanced-misaligned coupling faults. Finally, the influence of rotational speed on unbalanced-misaligned coupling fault shaft system is analysed. The simulation study shows that the vibration spectrum of shafting under unbalanced-misaligned coupling fault is mainly the superposition of the spectrum under each single fault, and the vibration caused by each fault is different in different locations. The increase of speed will aggravate the vibration of shafting.
Research on the Construction of Green and Environmental Protection Modern Gymnasium
Authors: Wei Zuotao
Published: March 2021

The lighting and air-conditioning of gymnasium buildings consume huge amounts of energy. How to make full use of natural lighting and natural ventilation is the key issue of energy conservation and environmental protection in gymnasium buildings. The paper focuses on the main energy-saving measures of sports buildings, from the building form factor and window-to-wall ratio, the thermal parameters of the envelope structure, the construction method of the envelope structure, the energy-saving design of the air conditioning system, and the energy-saving design of the building electrical system. Analysing and discussing the water-saving design of buildings and other aspects, it provides beneficial practical experience for the development of sports buildings in the direction of environmental protection and ecology.
Launching system of helicopter aviation transient electromagnetic system
Authors: Mingren Shen
Published: March 2021

Aviation electromagnetic transmitters are used to ascertain the distribution and reserves of underground mineral resources. Among them, the launch subsystem is used as the energy source of helicopter aviation transient electromagnetic exploration equipment, and its performance will have a great impact on the exploration depth and accuracy of mineral resources. The structure and principle of the power conversion circuit of the transmitting subsystem are introduced. Complete the production of the power conversion circuit, and complete the test of several main performance indicators of the circuit. Laboratory test results show that the power conversion circuit has good performance and meets the design requirements.
China’s One Belt, One Road Strategy Research in Accordance with Globalization Trends
Authors: Zhu Yuting
Published: March 2021

"One belt, one road" construction conforms to the trends of world economic globalization, and also meets the requirements of the development of global governance system. "One belt, one road" has improved the circulation of commodities, funds, technology and personnel among countries, expanded the mutual interests between countries, and opened up new space for the development of the country.
Detection Method of Ship Target Infrared Polarization Image
Authors: Tuo Haonan , Shi Guochuan , Luo Xiaolin
Published: March 2021

In the face of complex background and severe weather environment, infrared polarization detection has obvious advantages. In this paper, the ship target detection method based on infrared polarization image is studied and the ship target infrared polarization image detection method based on local contrast is proposed. The ship target detection accuracy of the proposed algorithm is 0.956, and the false alarm rate of the ship detection is low, which verifies the effectiveness of the detection algorithm in detecting the ship target, which has great application value in military applications.
Structure Optimization of Electromagnetic Railgun Armature Based on Machine Learning
Authors: Yu Zhenyuan
Published: March 2021

The armature is an important part of the electromagnetic railgun. It may break, wear, and transition during the working process, which increases the difficulty of maintaining the railgun and impairs the service life of the railgun. Therefore, studying the armature structure of the electromagnetic railgun is of great significance to the design of the electromagnetic railgun. This paper selects the five armature structure parameters of armature shoulder thickness, tail length, wing tip thickness, front end thickness, and interference, and focuses on "using armature structure parameters to predict prestress" and "using prestress and other armature to predict the interference of structural parameters". This paper uses the linear regression method in machine learning to construct the model, and use the normal equation method and the regularized normal equation method to optimize the loss function. The results show that the normal equation method is generally effective for the electromagnetic railgun structure optimization problem discussed in this paper.
Effect of Rehydration Ratio and Inlet Pressure on Shock Wave Focus in Hemispherical Concave Cavity
Authors: Peng Wenrui
Published: March 2021

Shock wave focus is a phenomenon where energy is rapidly converged in a small area of the medium through the interaction of shock waves, resulting in extremely high temperature and pressure near the aerodynamic focus. Experimental and numerical studies are in progress using the high energy area generated by shock wave focus to induce detonation to study shock wave focus phenomenon, the experiments of shock wave focus in the hemispherical concave cavity was carried out. The emphasis is placed on the effect of ring vent width and inlet pressure. By comparing the peak pressure at the bottom of the concave cavity under different ring vent widths, it was found that the reflection of the incident shock wave formed in the channel decreased with the width of the ring vent as well as the intensity of the shock wave increased. The greater the intensity, the more likely it is to produce the focusing of the shock wave. When the subsonic speed airflow flowed into the cavity through the ring vent, it was found that under the influence of the reflection of the concave cavity and complex motion of shock wave, a local high temperature and high pressure area was formed. By comparing the pressure spectrum at the bottom of the concave cavity under different flow pressures, it was found that with the increase of the flow pressure, there were two whistling modes on the spectrum map, C1 and D1 modes, respectively. It was also found that the pressure pulsation in the concave cavity was more disordered and the magnitude was smaller when the inlet pressure decreased, which means the shock waves were not well focused. It can be concluded that in ignition experiments, inlet pressure is significant to shock wave focusing phenomenon and there is a prompt rehydration ratio which lead to better shock wave focusing.
Research on an Analysis method of Engineering Mechanics in Bridge Field based on Machine learning
Authors: Gao Xinyi
Published: March 2021

The identification of bridge cable force has a great influence on the safety and reliability of arch bridge structure, which is a difficult problem in bridge construction. According to a certain tension sequence, the required sample library of suspender cable force is obtained by establishing the finite element model by MIDAS software. The designed cable force of the bridge is taken as the input vector of the radial basis function method (RBF method), and the initial cable force obtained is the output vector. The solution accuracy is controlled by distributed density parameters, the nonlinear mapping relationship between them is approached, and the initial cable force of suspender is calculated directly. The experimental results show that the error between the calculated value and the design value of the cable force can be controlled within 5% by the BRF method, which meets the engineering requirements.
Design and Verification Test of the Primary and Secondary Stage Compression Gap Size of Miniature High Pressure Air Compressor
Authors: Yang Lihua , Fang Bo , Qu Shengguan , Li Xiaoqiang , Mao Tao , Gao Hongyun , Xia Yumeng
Published: March 2021

Aiming at the prominent problem of the primary and secondary pistons hitting the cylinder head in the current miniature high-pressure three-stage air compressor, a design study on the size of the primary and secondary compression gap is carried out. Through the theoretical force analysis of the connecting rod, the force situation of the connecting rod at the top and bottom dead centers is obtained. The three-dimensional models of connecting rod and cylinder are established based on SolidWorks software, and the three-dimensional models are simplified. Based on Ansys Workbench software, the connecting rod and cylinder models are pre-processed, model discretized and post-processed. The structural statics and steady-state thermal comprehensive analysis of the connecting rod at the upper and lower dead points and the steady-state thermal analysis of the cylinder under working conditions are completed. Through analysis, the total axial deformation of the connecting rod and the total axial deformation of the cylinder under high temperature and high speed working conditions are obtained. According to the simulation analysis results, the first and second compression gap size is designed. Based on the design results, ten sets of air compressors are tested for dimensional design verification. The test results show that the air compressors of each test group can complete the charging requirements within the specified time, and there is no phenomenon of piston hitting the cylinder head, indicating the size design reliability.
A Design of Lowpass Filter with High Suppression in Stopband
Authors: Jin Liang , Li Xiaojun
Published: March 2021

Beeline compact microstrip resonance cell (BCMRC) is improved to reduce return loss. A lowpass filter in terahertz band is formed by two improved BCMRC cells and a central microstrip, which make the two cells incorporate into one structure successfully. The filter has widened stopband and high suppression characteristic under the same filter’s order. The optimized result is proposed with an insertion loss of less than 0.4dB in the lowpass band from 0 to 100GHz. The stopband with attenuation more than -20dB is from 140GHz to 350GHz, and the stopband with attenuation more than 40dB is from 158GHz to 312GHz. The size of the low-pass filter is 0.8mm×0.4mm, and this filter can be used in mixer or other devices of terahertz.
2μm widely tunable thulium-doped fiber laser seed oscillator
Authors: Hu Peixin , Ji Encai , Nie Zilin , Deng Jinchao , Yao Lu , He Zhengdi
Published: March 2021

2μm band laser can be used in transparent plastic welding, soft tissue laser surgery, LiDAR, toxic hazard gas sensing and medium-and far-infrared parametric oscillation conversion. However, there are still many problems that need to be clarified on how to break through the peak power limit, realize pulse time domain programmable and laser wavelength wide range tuning in the nanosecond thulium fiber system. In this experiment, wide tuning laser at 2μm band was used to realize different laser wavelength, constant seed laser power output, and EOM was used to define laser pulse waveform and pulse frequency.
Research on Low-Power Main Control Chip Architecture Based on Edge Computing Technology
Authors: Cui Guoyu , Ye Wei , Hou Zhanbin , Li Tong , Liu Ruolin
Published: March 2021

With the continuous development of the times, chip technology has also been innovated. In order to meet the needs of edge computing networks and data communication networks, it is necessary to make chips with shorter delay time and lower power consumption, which in turn brings challenges to chip architecture design. In the field of chip design, the problem of chip performance has been overcome. In many edge design networks, the core of the design is to allow the chip to meet low power consumption requirements, thereby extending the use time of edge devices. This article conducts research on a low-power master chip architecture to enable it to meet the needs of edge computing networks and enhance product competitiveness.
Research on Track and Field Teaching and Training Based on Computer-Aided Analysis
Authors: Lu Changchun
Published: March 2021

At present, the primary method of sports biomechanics research in track and field events is to use a high-speed image analysis system to monitor the training process and obtain kinematics information through special or general analytical software. To improve the training efficiency and correct the defects of technical movements in time, coaches urgently need a kind of equipment that can feedback the movement information in time during the training. Because of this situation, a track and field training information acquisition and feedback system based on a digital track are proposed based on sufficient condensing project requirements. The system USES flexible array sensors obtain contact interaction information during the run-up, and USES special analytical software to process kinematic parameters in an integrated manner, providing real-time biomechanical parameters such as step length and speed step frequency, and takeoff force in the process of moving. The system realizes the comprehensive analysis of sports representation and internal mechanical factors, which helps coaches and athletes to deeply grasp the internal law of the project. Its effectiveness and scientificity have been preliminarily verified through the athletes’ testing in the national track and field team’s long jump event.
Design and Implementation of Information Service System of Hunan Regional Seismic Network
Authors: Tang Hongliang , Zhang Yimei , She Xuming , Kang Chengxu , Tian Youping
Published: March 2021

In this paper, the framework of one-stop application service system of Hunan Regional Seismological Network is introduced, taking the fast earthquake reporting of Hunan Regional Seismological Network as an example, in order to realize the automatic, one-stop application service of graphic and text data display, which integrates "obtaining earthquake parameters-issuing earthquake message-completing website earthquake situation update-automatically sending fax".
Optimization of Train Operation Scheme for Container Sea- Rail Multimodal Transport
Authors: Hu Guojie , Sun Wanhua , Jiang Jian
Published: March 2021

In the past, the external costs, such as transportation costs and transit costs, are usually considered in the model of container sea-rail multimodal transport, without considering the time value cost of goods and the social costs such as traffic accident cost and environmental pollution cost caused by the transportation process. Goods transportation is a kind of social and economic activity. The whole transportation process of goods from the place of departure to the destination needs time. When time is connected with specific social and economic activities, it has value, that is time value. [1] The time value cost of goods will become a large part of the cost in the process of transportation. Improving the efficiency of goods transportation is a major goal of goods transportation. However, while improving the efficiency of goods transportation, we should also take into account the social costs brought about by the transportation of goods. In this paper, the time value of goods and social cost are considered to optimize the operation scheme of container sea-rail multimodal transport trains.
Line loss prediction based on particle swarm optimization combined with extreme learning machine
Authors: Qin Huaqin , Liu Jianfeng , Guan Yiqun
Published: March 2021

As a key economic index to measure the planning and management level of power grid company, line loss is not only the main content of completing the construction and transformation task of power grid company, but also an important assessment standard for the operation level of power grid company. In order to improve the generalization ability and prediction accuracy of extreme learning machine (ELM), particle swarm optimization (PSO) algorithm is applied to extreme learning machine (ELM), and a line loss prediction method based on PSO combined with ELM is proposed. The particle swarm optimization algorithm is used to select the optimal hidden layer deviation and input weight matrix to calculate the output weight matrix, so as to improve the accuracy and stability of the extreme learning machine. Experimental results show that the proposed method can effectively improve the accuracy of line loss prediction.
The Application of Financial Mathematics in the Market Analysis of the Electrical Industry
Authors: Wu Linlin , Liu Kai , Zhou Wei
Published: March 2021

With the rapid development of the financial market in the economic field, more and more financial problems need to be solved with mathematical knowledge. This article combines the development history and current status of each electrical appliance, from the three aspects of solvency, operating capacity and profitability. In terms of analyzing the company’s financial ratio, the company’s current ratio, asset-liability ratio, return on equity, and total return on assets of the company in the past three years were calculated.The analysis of these indicators revealed that the assets of Shanghai Liangxin Electric Co., Ltd. The debt ratio is extremely low, and the risk is small. However, in comparison with competitors in the same industry, we find that the company’s profitability is at the middle and upper levels, and the overall development trend is good in the past three years, but it is generally higher than the industry’s advanced level. Companies still need improvement.
Research on Mobile Terminal Technology Supporting Intelligent Maintenance of Substation
Authors: Zhao Zhanglei , Yang Jianyou , Xi Honglei , Wang Jiaxing , Gao Bingwei
Published: March 2021

In view of the fact that traditional substation maintenance operations need to carry a large amount of paper data and the on-site paperlessness is low, a mobile terminal supporting intelligent maintenance of substations has been developed. Introduce the development background, system integration scheme, various management functions of the device and its application in substation maintenance operations, recorder viewing and grid fault analysis. The application of the mobile terminal can improve the intelligence level and convenience of on-site maintenance operations, shorten maintenance time, improve maintenance quality, and improve the level of relay protection lean management.
Design of Simulation and Verification Software of Crew Operation Program
Authors: Yang Shuo , Wang Yingsheng , Man Yi
Published: March 2021

For easily and timely simulating and verifying the design of crew operation programs, improving the rationality of the design, the open source graphic display framework Qt based on the Windows platform is used to design and development of crew display and operation software. It can provide support for the system designers to further optimize the design. This program has been adopted in a pre-research project with major background.
Research on Information Security System of Ship Platform Based on Cloud Computing
Authors: Lin Tao , Zhao Yang , Zhang Haotian , Li Guobing , Zhang Jian
Published: March 2021

To improve ship positioning identification and implementation monitoring, ensure the safe navigation of ships, and optimize ship information retrieval design, the paper proposes a ship information retrieval system based on cloud computing technology. It adopts the fuzzy C-means clustering method for ships, the classification and processing of the subordinate characteristics of the information, the design of the ship network video monitoring system, some study of the critical technology of cloud computing technology, and the algorithm of the video image detection. The simulation results show that this system has a siginificant improvement on accuracy and recall rate of ship navigation safety information monitoring. The system is a ship-shore integrated monitoring platform that meets maritime safety requirements and the needs of low- carbon management with outstanding efficiency.
Convergence of Online Gradient Method with Momentum for BP Neural Network
Authors: Pan Chengyan , Xie Gang
Published: March 2021

The BP neural network, which uses the steepest descent method (gradient descent method) as the basic idea for learning, is often used to deal with approximation problems because of its strong nonlinear mapping ability. The gradient method with added momentum can improve the learning speed of BP neural network. We study the convergence of the online gradient method with momentum for two-layer BP neural network when the training samples are randomly arranged in each iteration. Choosing appropriate learning rates, and selecting momentum coefficients in an adaptive manner, we prove the weak and strong convergence theorems of the algorithm.
The Influence of Speech Translation Technology on Interpreter’s Career Prospects in the Era of Artificial Intelligence
Authors: Jiang Kai , Lu Xi
Published: March 2021

As the advancements in artificial intelligence, discussions on whether machine translation will replace human translation are found in the media and the public, but scholars have rarely explored this in research. This paper first reviews the history and recent progress in speech translation technology, and analyzes its merits and limitations. Then, in view of the history and features of the interpreting profession, the paper discusses the influence of speech translation technology on interpreter’s career prospects. The author holds that even if future speech translation technology is highly sophisticated, it still cannot completely replace human interpreters. Artificial intelligence is considered as both a challenge and an opportunity for the translation industry. The future trends in interpretation will be mainly human-led and machine-aided. After analyzing the trends and challenges to the interpreting profession, the paper proposes suggestions to interpretation teaching, hoping to give reference to interpretation teachers, learners and researchers.
Performance research and Simulation analysis of magnetorheological torque servo device
Authors: Sha Shujing , Zhang Fuhao
Published: March 2021

This paper expounds the rheological mechanism of magnetorheological fluid and the working principle of magnetorheological moment servo, studies the relationship between excitation current and magnetic field strength, magnetic flux and magnetic flux potential, and analyzes and designs the magnetic circuit. The electromagnetic analysis of the magnetorheological moment servo device was carried out by ANSYS software, and the relevant information such as the distribution of magnetic field lines and magnetic induction intensity was analyzed. The relationship between excitation current and magnetic flux density was obtained by fitting the data under different excitation current. The quantitative relationship between the input current and output torque of the magne-orheological drive device is simulated by matlab software.
A Dynamic Reconfiguration Scheme for Embedded System Based on Multi-core DSP
Authors: Liu Xiaojian , Liu Shuo , Lv Hao
Published: March 2021

High-performance embedded system is needed in high-speed and accurate avionics control systems, but its hardware resources are limited. It is of great significance to reuse hardware resource through static or dynamic reconfiguration. A dynamic local reconfiguration scheme is designed based on c6678 isomorphic multi-core DSP to realize the dynamic reconfiguration of software on a single core under the premise of ensuring the normal operation of the whole system. This reconfiguration scheme can realize the complete switching of software on the whole core and realize the time division multiplexing of multiple algorithms in the same memory space. Experimental results show that the scheme can fully meet the requirements of real-time.
Research and development of "Internet + training" collaborative simulation platform
Authors: Wang Jin , Li Jie , Kang Yi , Wu Ping , Sun Aichun
Published: March 2021

This article introduces a development method of "Internet + training" collaborative simulation platform. It explains in detail how to make full use of Internet technology to bring convenience to the development of power system simulation training platform, and to solve the problem of coordination of simulation calculation. The method can effectively use the computer resources of the training system, avoid the waste of resources of the training system on the simulation computing platform, and reduce the investment in hardware equipment. Finally, this article verifies the feasibility of the development method proposed in the article through a practical case.