bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibrational fatigue failure prediction of a brake caliper used for railway vehicles based on frequency domain method
Authors: Zeng Liangbin , Zhao Jinliang , Meng Yongshuai
Published: June 2021

A brake caliper used for railway vehicles was introduced in this paper. In order to predict the fatigue failure under random vibration condition, firstly a dynamic model was established and proved by comparing the results of modal simulation and modal test. The weak points of the structure were identified by taking random response analysis, and the corresponding PSD (power spectral density) spectrums of stress were obtained. Furthermore three different PDF (probability density function) models of stress amplitude distribution were employed to describe the distributions of stress at weak points, then the fatigue damages were calculated based on Miner’s linear cumulative damage theory and the fatigue failures were predicted. Finally, an accelerated failure test was designed and carried out to verify the validity of the predictions proposed by three models. The result shows that, the Dirlik’s model and Steinberg’s model can provide more exact results and be suitable for vibration fatigue failure prediction of brake caliper.
Design of A Free Floating Ultrasonic Inner Spherical Detector for Pressure Pipeline
Authors: Du Xingji , Fang Xin , Tian Wei , Tang Ping , Miao Cunjian
Published: June 2021

Ultrasonic inspection of the corrosion and scaling in industrial pressure pipelines is necessary due to the adverse effects of defects on medium flow and heat transfer. In this paper, a free floating ultrasonic inner spherical detector has been designed to detect and locate defects in pipelines. The flange mechanical structure of ultrasonic inner detection intelligent ball meets the internal space requirements and external environmental requirements. They are connected of two parts flange type. A complete set of spherical shell structure design covering the functions of sealing and external pressure resistance is proposed and completed. One part is the inner sphere, and the other is the outer shell. Pipeline experiments show that the spherical detector can reach the exit smoothly through curved pipes, inclined pipes and vertical pipes without jamming and stable motion attitude, collects all kinds of information along the way, determines the existence of defects and achieves accurate positioning.
Application and research of patent evasion design in automatic connection device
Authors: Zhen-guo Li , Gong-chang Ren , Yue-xin Yang , Le Wang
Published: June 2021

The patent evasion design may reduce the value of the original patent. In order to avoid this possibility, it is necessary to analyze the development status of the patented technology while conducting the patent evasion design. Combining value analysis with patent evasion methods, a patent evasion design method based on value analysis is proposed. Firstly search related patents by identifying multi-level keywords to obtain the target patent database; then predict and analyze the maturity of the database patents to determine the core patent group; the structure/function model of the core patent is established and its value analysis is analyzed to find the low-value components as the target technology of the circumvention design; next, the contradictory points of the target patent are found through the TRIZ theoretical tool to perform the evasion design, and the new scheme is obtained and the infringement judgment is made. Finally, the method was verified by an automatic connecting device, and the result showed that the improved automatic connecting device has the advantages of simple structure and convenient operation.
Quadrotor Flight Control Based on Improved Active Disturbance Rejection Control Technology
Authors: Xiyang Wang , Mingqiu Li , Yang Yang , Hongtao Duan
Published: June 2021

This paper proposes a four-rotor attitude control method based on improved active disturbance rejection control. Based on the analysis of the active disturbance rejection controller from the deviation theory, it is found that the extended state observer has problems such as high steady-state error and difficulty in parameter selection. Then, an improved extended state observer was designed structurally, its stability was proved and the error was compared with the traditional extended observer, and the improved auto-disturbance rejection control was applied to the attitude control of the quad-rotor UAV. Finally, the simulation verification of the controller is carried out from various aspects of attitude tracking, height-fixing experiment, external force interference test and wind interference test, and compared with traditional ADRC, the comparison results show that its performance is better than traditional ADRC.
Research on the Design of Brake Auxiliary Device Based on the Improvement of Riding Safety
Authors: Zeng Xi , E Zheheng
Published: June 2021

Purpose: In order to improve the safety of the braking action of cyclists during the riding process, to meet the diversified riding needs of cyclists, and to take care of special riding groups to achieve the purpose of improving user experience. Method: Use ergonomics to guide the design of bicycle brake assist device, analyze from the perspective of ergonomics the elements and methods for achieving safe operation during bicycle braking, and complete the design of the brake assist device based on this analysis. Conclusion: It provides a new type of braking mode, reduces the difficulty of braking, improves the riding safety and comfort, and makes the product have important application value and better base on the market.
Research on feasibility verification method of pipe bending angle correction
Authors: Guo W S , Guo R , Sun H H , Wang W , Yang X
Published: June 2021

Certain types of rocket engine pipes can only be cut perpendicular to the axis when cutting margins. In order to verify whether the pipeline can achieve the cutting margin perpendicular to the axis by correcting the bend angle, and finally perform accurate assembly, a verification method based on SolidWorks to simulate the pipe shaping process is proposed. First, the pipe model was reconstructed by using the measurement data. Second, the lengths of the pipe segments, the angles between the line segments and the angles between adjacent surfaces were extracted. Third, the simplified pipe model and interface model were established and assembled in SolidWorks. Finally, the angle constraints of the adjacent surfaces were added, and the angle constraints of the line segments were released. According to the assembly results, the feasibility of solving the problem through shape correction was analysed. Experiments show that this method can effectively verify the feasibility of the shape of the elbow, and also provide the shape of the pipe after the correction and the angle of each elbow.
Hand Gesture Controlled Nursing Bed Using FMCW Radar
Authors: Du Fuchuan , Zhao Yue , Wang Haili , Cao Qixin
Published: June 2021

The nursing bed has become an important tool for medical and elder care, as a well-designed bed can prevent users from bedsores. To improve the user convenience, a user-friendly human-computer interface is also necessary. In this paper, we design a new nursing bed containing a FMCW millimeter wave radar for gesture recognition. A control system can help user frictionless back-up, integral turning over and leg raising when lying in the bed. Besides, we adopt the convolutional recurrent neural network for recognition of 6 gestures. Experiments with the nursing bed show that the control success rate of the bed reaches 93.75% and the response time achieves 1.03 s.
Research on the scheme of radio cooperative spectrum sensing for offshore ships based on trust degree in Ad Hoc network mode
Authors: Zhang Jiaming , Zhang Baihai , Chai Senchun , Cui Lingguo , Yao Fenxi
Published: June 2021

Radio communication is an important part of maritime communication. As the number of ships in the offshore area continues to increase, spectrum resources appear to be particularly tight. In this work, a trust-based cooperative spectrum sensing scheme in Ad Hoc network is proposed to improve the accuracy and reliability of maritime radio communications. This scheme first divides the ship nodes into different subnets according to the Ad Hoc network protocol. And after the malicious ship nodes are selected based on actual conditions, a trust-based collaborative spectrum sensing fusion method will be given, that is, a smaller trust weight is given to malicious nodes, the method will be more trustworthy to receive the spectrum occupancy information provided by ship nodes with a higher degree of trust. Simulations have been performed to illustrate the high detection probability of the proposed spectrum sensing scheme. Therefore, it is feasible and beneficial to apply the proposed spectrum sensing scheme to improve the trustworthiness of maritime radio communication.
A SlW-CPW-fed high-gain antipodal Vivaldi antenna with elliptical dielectric lens
Authors: Zhen Fajian , Li Xingguang
Published: June 2021

This paper proposes a Ka-band high-gain antipodal Vivaldi antenna. The antenna is designed by SIW-CPW power feed. Both ends of the radiating arm are loaded with elliptical patches, claw-shaped slots and rectangular corrugations are loaded on the patch, and elliptical lens are loaded on the front end of the radiating arm, and four rows of metal strips are loaded on the lens. The proposed antenna has overcome the shortcomings of the traditional Vivaldi antenna’s high feed loss, and better improve the antenna gain. The Ka-band antenna shows excellent radiation performance, with a peak gain of up to 12.1dBi.
Research on obstacle avoidance method of robot manipulator based on binocular vision
Authors: Zhang Xiaoyang , Guo Xiaoming , Sun Zhenyu
Published: June 2021

Aiming at static obstacles in indoor environment, the six-axis robot manipulator can avoid obstacles successfully through binocular stereo vision system. According to the principle of camera imaging, the camera calibration is completed by using the camera calibration toolbox of MATLAB, and then the three-dimensional coordinates of the feature points of obstacles are obtained by using the Structure from Motion (SFM) algorithm, so as to determine the location of obstacles. In the aspect of path planning, combining the characteristics of binocular visual obstacle recognition, the artificial potential field (APF) method is used to realize the obstacle avoidance. Finally, the simulation and data analysis under the Matlab development environment verify the feasibility of the algorithm in the binocular vision obstacle avoidance system.
Research and application of TRIZ theory in the field of service robots
Authors: Jiahao Feng , Gongchang Ren , Yuexin Yang , Yadong Shang
Published: June 2021

Service robots in China are in the rapid development, with an increasing proportion in the field of robotics, but there is still a big gap with other developed countries in the core technology, systematic innovative design theory guidance is particularly important. Therefore, FEPAM model (function-effect-process-action-mechanism model) and TRIZ (Teoriya Resheniya Izobreatatelskikh Zadatch) were integrated. First of all, through the analysis of the market demand and existing products, the working mechanism is decided. According to the mechanism, the process action process is conceived. Finally, the executive mechanism that needs to be improved is determined. By establishing the Su-field type and adopting the corresponding standard solution, the product function innovation is realized. The proposed method is applied to a delivery robot, and the problem of inconvenient man-machine operation is solved quickly. The results show that the proposed model can improve the solving speed of the Su-field model, enrich the standard solution model, and provide a new idea for the future development of Su-field model.
Water Leakage Detection Based on Variation Bayesian Neural Network Autoencoder
Authors: Feng Pengyu , Shen Yixuan , Liu Weiming
Published: June 2021

Water pipe leakage detection is of great significance to the protection of water resources in our country. However, the detection accuracy of water pipe vibration signals is easily affected by external noise. Existing detection technologies are difficult to reduce the influence of noise signals, and some machine learning based outlier detection models are not very robust. Variation Bayesian neural network Autoencoder (VBAE) replaces the fully connected layer network in encoder and decoder with Bayesian neural network (BNN) on the basis of Variation Autoencoder (VAE). VAE has a strong generalization ability, while BNN has an uncertainty quantification ability. VBAE combines the advantages of the two models and is very robust. Experiments have proved that, compared with other models, VBAE for water leakage detection can greatly reduce the influence of noise on the output of the model, and has a better detection effect.
Lightweight robust optimization design of mechanical claws of intelligent sanitation vehicle
Authors: Li Ran , Xu Xiang , Chen Jiawei , Chen Xinbo
Published: June 2021

As the dustbin grabbing device of the intelligent sanitation vehicle, the dimension errors caused by the manufacturing process should be considered in the lightweight design process of the mechanical claws. In this study, we used the mechanical claws as the carrier. The maximum deformation and the maximum equivalent stress of them were taken as the design responses and the plate thicknesses of different parts were taken as the design variables. A light-weight robust optimization design method for the mechanical claws was proposed by combining the optimal latin hypercube experimental design with high-precision Kriging approximate model and using Particle Swarm optimization (PSO) as the optimization solver. The optimization results show that this method has higher robustness than traditional deterministic methods although it has lower lightweight requirements. The final structural design of this study has higher advantages in preventing the fluctuation of uncertain parameters.
Rolling Element Bearing Fault Diagnosis for Complex Equipment based on MFMD and BP Neural Network
Authors: Liu Junfeng , Yu Xiang
Published: June 2021

A new fault feature extraction method for rolling element bearing is put forward in this paper based on modified Fourier mode decomposition (MFMD) and multi-scale permutation entropy, and the fault pattern recognition is studied by combining BP neural network. First, introduce frequency band entropy (FBE) to optimize the boundary frequency search and effective modal component selection of Fourier decomposition. Then, use MFMD to adaptively decompose the original vibration signal to several Fourier intrinsic mode functions (FIMFs) and select effective FIMFs. Next, use multi-scale permutation entropy to quantify the fault features. Finally, input the fault feature vector into the BP neural network for fault diagnosis model training and testing. The method proposed in this paper is applied to the rolling element bearing simulation data and the public bearing fault test data set of Case Western Reserve University to verify the feasibility of the method. The results show that the method proposed in this paper has a high identification accuracy for different types of faults, reaching over 98%. The feasibility and superiority of the rolling element bearing fault diagnosis method based on MFMD and BP neural network are verified, and technical support is provided for the health state assessment of rolling element bearings.
Automatic detection of COVID-19 chest X-ray based on Convolution Neural Network
Authors: Ye Qing , Tan ZeXian
Published: June 2021

Currently, chest X-rays, as one of the auxiliary diagnostic methods for COVID-19, play an important role in the detection of COVID-19. In this paper, we propose an automatic detection method of COVID-19 chest X-ray based on Convolution Neural Network. In this method, we first get an image of the chest by X-ray, and then we preprocess the chest X-rays, and then send the preprocessed X-ray images to the convolutional neural network for feature extraction and classification, and finally we were able to diagnose whether COVID-19 or not. We test the three types of models (Inception V3, ResNet and DenseNet) under different layers, and finally propose the automatic detection method of COVID-19 chest X-ray. After a large number of experiments, the highest accuracy rate of COVID-19 detection is 98.059%. Compared with other studies in the same period, our accuracy rate is higher, and it is very fast. This indicates that our proposed method can be used as an auxiliary detection for COVID-19.
Analysis of Contact force optimization for a hybrid manipulator
Authors: Canguo Zhang , Shaolei Wang , Yi Lu , Xiaoyu Ni , Chunhua Zhu
Published: June 2021

A novel hybrid manipulator is designed. Based on the fact that the sum of the external force vector for the object is zero, the criterion of the stability of the object is derived. The formula for calculating contact force of fingers was deduced by matrix theory. The maximum frictional force was taken as boundary condition, then the contact force of fingers was optimized. The advanced CAD software was used to simulate the process of grasping the object. The stability of the object at a certain time was verified. Finally, the contact force between fingers and objects was optimized. It provides a theoretical basis for the application of the hybrid manipulator.
A study on the wear allowance of a railway vehicle hydraulic damper
Authors: Wang Wenlin , Huang Bao , Zhou Zirong , Du Jianming
Published: June 2021

Railway vehicle hydraulic dampers are usually subject to wear-induced premature failures, so it is meaningful to evaluate the wear allowance of the hydraulic damper. Mathematical modelling of damping characteristics of a railway vehicle hydraulic damper under wear conditions is carried out, the model describes the functions of main damping characteristics indices vs. inner tube wear M1
and rod wear M2
. Simulation is then performed using the model, and indicates that increase of M1
would lead to significant drop of the maximum extension damping force, fading of the damping coefficient and significant rising of the damping force asymmetry rate, but the maximum compression damping force keeps to be constant, while increase of M2 would lead to significant drop of almost all of the indices except for the asymmetry rate. A wear allowance line for the damper is finally obtained when both of M1 and M2 work in real situations, the area enclosed by the wear allowance line and two axles is a safe area, any dot with a combination of M1 and M2 outside the safe area means the damper has exceeded its wear allowance and should be maintained or replaced. The mathematical model and the wear allowance line obtained in this work can be used for health status evaluation and design optimization of railway hydraulic dampers.
DEKA VII Multipoint Fuel Injector Characteristics Study
Authors: Li Fu , Weidong Xiang
Published: June 2021

A saturated injector driver is a power transistor driver circuit that turns fully on, and electrically saturates for the entire duration of the injector pulse width. This type of driver is better used with injectors having high resistance coils (12~16 Ohm). The advantage of this type of injector driver is that electrically generated heat is dissipated through the injector and not through the power transistor of the driver circuit. The circuitry is simplified compared to a peakand-hold type driver (which requires heat sinks to dissipate the electrical load).
Research on double tower dryer based on air brake system of rail vehicle
Authors: Xu BuDu , Zhang Xuan , Zhang ShiXi , Li QingXuan , Zhu XiaoYu
Published: June 2021

as we all know, in the air brake system of rail vehicles, the air usually contains moisture. In order to solve this problem, the common air dryer can effectively dry the compressed air and thoroughly remove the moisture of the braking system. At present, the dryer used in vehicles has many disadvantages in logic control. The efficiency, service life and air resistance of the dryer do not meet the goal of smaller volume and higher parameter index, so a more excellent dryer is urgently needed.
A new path of energy saving and emission reduction based on the choice of matching engine oil for tor traditional energy vehicles
Authors: Changming Xia , Leping Bu , Qi Zhou , Shengliang Wang , Yanhong Guo
Published: June 2021

Comparative test research for the same and different models with matching type oil has been carried outunder same and different conditions. The results show that the parameters such as idle speed, load calculation value, absolute position of throttle, injection pulse width and fuel repair value of all the tested engines are reduced to different degrees by using the matching type oil. Energy consumption, emissions and other indicators of vehicles with matching type of oil have been improved after long-term tracking, especially large diesel vehicles.
Reliability analysis of the optimized carrying door frame based on six-sigma
Authors: Chen Di , Wang Yunxia , Liu Ruilong , Zhang Jun , Qiu Longjing
Published: June 2021

The door frame is a key component of the track door system. This paper uses the Six-sigma Analysis module in the finite element software ANSYS Workbench to analyze the reliability of the door frame, and regards its geometric dimensions and materials as random variables. Test design, Latin hypercube sampling, and Monte Carlo simulation calculations respectively obtained the reliability values of static strength and static stiffness of the door frame. The reliability values were analyzed to verify the rationality of the design.
Research on Integrated Pneumatic Control Valve Based on Frame Control Brake System of Rail Vehicle
Authors: Xu BuDu , Zhang Xuan , Zhang ShiXi , Li QingXuan , Zhu XiaoYu
Published: June 2021

This product is used in the frame control system of railway vehicles. It integrates remote function, anti-skid function and communication function, and highly modularizes the common braking, emergency braking and anti-skid protection functions of railway vehicles.
Effect of cooling methods on mechanical and corrosion properties of Inconel 625 during solution treatment
Authors: Li L , Liu X Y , Wang X , Wu M
Published: June 2021

Inconel 625 alloy is a nickel-based deformation superalloy which is widely used in aviation, ocean engineering, chemical engineering and other important fields. In recent years, with the continuous expansion in application field of Inconel 625 alloy, the requirements of mechanical properties, corrosion resistance and other comprehensive properties of the alloy are constantly improved. In this paper, hardness tester, tensile machine, electrochemical workstation, optical microscope, scanning electron microscope and other equipment are used to study Inconel 625 alloy, and the microstructure evolution law and mechanical properties and corrosion properties of the alloy under different heat treatment conditions are studied. The experimental results show that the as-cast Inconel 625 alloy is mainly composed of austenite which is displayed high hardness and poor corrosion resistance. Heat treatment is a common way for tunning the comprehensive properties of Inconel 625 alloy. After 1090°C heat treatment, different cooling method were used to tune the corrosion resistance of Inconel 625 alloy. The cooling rate has a great influence on the microstructure and properties of the alloy. After water cooling, the precipitation of Nb carbide at the grain boundary is retained, which improves the corrosion performance of the alloy. After air cooling or furnace cooling, chromium carbide precipitates in the alloy again, which leads to the decrease of corrosion properties of the alloy. The special treatment can effectively improve the corrosion resistance of the alloy, and improve the plasticity of the material without reducing the strength. This paper provides an effective basis for optimizing the heat treatment process of Inconel 625 alloy in production to improve the comprehensive properties of the material.
Optimal Design of Lifting Mechanism of Linkage Hydraulic Lifting Dam Based on MATLAB
Authors: Chen Yuanlong , Cheng Zhuangzhuang , Huang Zhendong
Published: June 2021

The muti-link lifting mechanism in hydraulic dam was briefly introduced. The optimization model of the lifting mechanism is established, and the stroke of the hydraulic cylinder is taken as the optimization objective. The genetic algorithm and fmincon function in MATLAB are used to optimize the connecting rod parameters. The results show that the genetic algorithm can obtain the optimal value in a small number of iterations, but it takes a long time; while the fmincon function can obtain the optimal value in a short time under suitable initial value conditions, but the number of iterations is more. It provides a basis for further research on the multi-link lifting mechanism.
Three-dimensional finite element simulation of high speed milling of titanium alloy Ti6Al4V
Authors: Wang Zhenda , Ze Xiangbo , Yousuf Yusuf Abudllahi , Jiang Zhenfeng , Fu Xiuli , Pan Yongzhi
Published: June 2021

In this paper, ABAQUS finite element simulation software was used to establish a more reliable three-dimensional milling titanium alloy Ti6Al4V finite element simulation model. This model sets up important links such as the material constitutive model, the tool-chip contact friction model, and the chip separation criterion. And the accuracy of the model is verified by experiments. Based on this model, orthogonal experiment was used to explore the effects of axial cutting depth, tool speed and feed speed on the milling force. And the morphology of the chip and the surface morphology of the machined workpiece were investigated. The results show that the influence of cutting parameters on milling force from high to low is as follows: axial cutting depth > tool speed > feed rate. The change of cutting parameters has different influence on milling force in all directions, and has the largest influence on milling force in X direction.
An experiment study on deterioration of dynamic rotational accuracy of motorized spindle
Authors: Hu GF , Jia CM , Fang Y , Lv SL , Zhang Y
Published: June 2021

High-speed precision spindle is one of the core functional components of CNC machine tools, and its life is the key bottleneck factor restricting the reliability of CNC equipment made in China. So far, the research on the life of motorized spindle is still in the initial stage, and lacks a systematic and complete theoretical support. Motorized spindle is a typical product with high reliability and long life, and it is difficult to have faults or obvious performance degradation in the limited test time, so the traditional reliability evaluation method based on statistical theory is not effective. Therefore, it is of great significance for the reasonable evaluation of the reliability level of motorized spindle to carry out the test technology research on the impact force and life of motorized spindle. In this paper, the spindle alternating load test device is developed. The relationship between alternating impact load and spindle precision retention is studied experimentally. Taking spindle rotation accuracy as the main assessment factor, the mapping relationship between alternating impact load and spindle system life was established.
Effect of Magnetic Field on Dynamics of 5% Propane/Air Premixed Gases
Authors: Yang Xigang , Hu Shoutao , Wang Le , Sun Xu , Hong Zijin , Li Ruxia , Shi Huiwen , Gao Jiancun
Published: June 2021

Under applying the gradient electromagnetic field of 2100Gs-3300Gs, the explosion pressure and the propagation velocity of the explosion flame of 5% propane/air premixed gases were studied experimentally. The experimental results showed that the gradient electromagnetic field suppressed the explosion overpressure and explosion flame propagation velocity. When applied the gradient electromagnetic field, the peak propane explosion pressure decreased by 26KPa and the explosion flame propagation velocity decreased by 1.54269m/s. In other words, the gradient electromagnetic field suppressed the increase of pressure shock waves and light waves. Through the numerical simulation of propane explosion reaction, it is inferred that electromagnetic field mainly inhibits propane explosion pressure and explosion flame propagation speed by affecting the reactions of • H, • O and • OH radicals.
Research on silent steady flow quick closing check valve for rail vehicle
Authors: Zhang Xuan , Xu BuDu , Zhang ShiXi , Li QingXuan , Mou ZhenYu
Published: June 2021

a kind of air valve which can prevent gas backflow is used in the track air supply system. Check valve is the basic component of fluid control engineering, which is widely used. It plays a role in determining the direction of fluid flow, protecting other fluid machinery and pipeline safety by preventing the reverse flow of fluid[1]. For example, drilling tool check valves commonly used in oil fields include arrow type valve, float valve and input type check valve [2-3]. The check valve developed by our company is mainly used for gas medium, suitable for high-pressure gas transmission, and plays the role of preventing gas backflow.
Research on Flow and Condensation Heat Transfer Coefficient of multi-channel cylinder dryer in U-shaped Section
Authors: yan Dong , Ji-xian Dong , Li-jie Qiao
Published: June 2021

The cylinder dryer is the most energy-consuming part of the papermaking drying section. Whether the drying cylinder can effectively drain the drying cylinder affects the drying efficiency of the drying cylinder. The design of the multi-channel drying cylinder effectively improves the problem of the difficulty of the water accumulation discharge. In order to obtain a channel cross-sectional shape with better drainage and better heat transfer, two channels with different cross-sectional shapes are selected to study the flow and heat transfer of steam in this experiment. The changes of the channel heat transfer coefficient under different working conditions are studied and compared. The result show that the U-shaped channel heat transfer effect is better than that of other shape channels in the multi-channel dryer.
Analysis of dynamic characteristics of thin-walled parts based on finite element method
Authors: Jiang HT , Jin G , Zhang XY , Sun GX
Published: June 2021

In order to study the stiffness and dynamic characteristics of thin-walled parts of different types and sizes, this paper is based on the finite element method for modal analysis of thin-walled flat parts and thin-walled curved parts. According to the first four natural frequencies and mode shapes of thin-walled parts under different height and thickness parameters, a frequency comparison chart of thin-walled parts with different heights and thicknesses was drawn, and the influence of different types of thin-walled parts and different heights and thicknesses on the frequency and vibration mode of thin-walled parts was obtained. Experimental results show: (1) With the thickness increases, the natural frequency of thin-walled parts gradually increases and with the height increases, the natural frequency of thin-walled parts gradually decreases; (2) Under the same height and thickness, the natural frequency of curved thin-walled parts is greater than that of flat thin-walled parts; 3) The change of the height and thickness of the thin-walled parts has a greater influence on the frequency changes of the flat thin-walled parts than on the curved thin-walled parts
Development technology of moon bag process template for knitted sports pants
Authors: Yin Xue-Feng , Lu-Ni  , Fu Ju-Fen
Published: June 2021

Clothing technology template is a special auxiliary clothing production tool, and it is a new mode of clothing production. The development of garment template technology is more and more extensive, but it is less used in knitted garments. Based on the theory of garment process template, this paper takes the moon bag of knitted sports pants as the research object, and uses jingwei garment template professional software to design its template, then cuts and assembles the template, so as to solve the demand of garment enterprises for high-quality products and high-tech personnel.
Interface damage analysis of composite hat-stiffened panels
Authors: Wang Tao , Bai Ruixiang , Wei Changlong , Huang Xiaodi , Bai Heshan
Published: June 2021

In order to reveal the mechanism of interfacial debonding damage of composite hat-stiffened panel, an eight-point bending model of single stiffened structure was designed. The finite element analysis was carried out by using the cohesive element to simulate debonding damage of interface between skin and rib. The deformation, interface stress and structural damage of the eight-point bending as well as the corresponding stiffened panel under axial compression were analyzed. The results showed that the initial debonding deformation was in good agreement with the interface stress distribution. For the eight-point bending model, although more damage appeared near the loading point due to stress concentration, it had little effect on the accurate prediction of interface damage behavior. The eight-point bending model can be used to evaluate the interface performance of corresponding multi-stiffened-panel during axial compression buckling by accurate simulation and parameter design, and it is helpful for the stiffness matching design of skin and stiffener.
Dynamic mechanical behavior and microstructure evolution of 7A52-T6 alloy at elevated temperatures
Authors: Yang Bing , Zhou Honggang , Liu Zicong , Huang Hao , Liu Wenhui
Published: June 2021

Dynamic mechanical behavior and microstructural evolution of 7A52-T6 aluminum alloy were investigated at elevated temperatures ranging from 150 to 350°C and strain rates ranging from 2000s−1 to 5000s−1 using a compressive hospitalization pressure bar (SHPB) system. The results show that 7A52 aluminum alloy has obvious temperature sensitivity, but the sensitivity to strain rate is weak. The effects of temperature on the microstructure of 7A52 aluminum alloy are significant, and the dislocation density decreases with the increase of temperature. With the increase of impact temperature, some of the η’ phases are dissolved, and some of them are transformed into η phases. This study in general provides a significant understanding on the relationship between microstructure evolution and mechanical behavior of 7A52-T6 aluminum alloy under dynamic loading and at elevated temperature.
Analysis of Research Situation of Wireless transmission of the Internet of Things Based on Bibliometrics
Authors: Qin Hui-Xian , Hao Yong , Miao Jing-Gang
Published: June 2021

In order to objectively analyze the development of wireless transmission research of the Internet of things, and provide reliable data reference for researchers and decision-makers of wireless transmission of the Internet of Things, this paper adopts the bibliometric method and selects web of science database to analyze the number of papers and citations of countries, authors, publishing organizations, journals, and research contents of wireless transmission of the Internet of Things. A total of 15102 authors from 3843 organizations in 87 countries and regions, which include China, the United States, South Korea, and India, and 6105 articles published in 551 source publications were retrieved from Web of Science database. The research content involves the research focus, current development status, application scenarios, and future trends of the wireless transmission of the Internet of things. In terms of quantity, the most powerful country in the world is China, which has published 1912 papers, accounting for 31.319% of the total number of papers. At the same time, the research on wireless transmission of the Internet of Things is relatively active in China, with a wide distribution of research organizations, a large number of researchers, and the highest number of publications. Among the top 10 high-yield organizations, 7 are Chinese organizations, and some Chinese scholars have published the article has a high frequency of citations, but the number of results of different research directions is not balanced, and the research direction is more inclined to the direction of machinery, computer science and communication.
Application of inductance in the field of liquid level sensors
Authors: He Guoyu , Zhou Zongluan
Published: June 2021

Aiming at the application limitations of traditional inactive liquid level sensors (mainly ultrasonic and light waves), In this article, the relationship between inductance and medium is quantified in specific application scenarios, which can implement the functions of traditional liquid level sensors and solve different The influence of liquid composition and state on data, this research expands the application fields of liquid level sensors.
Modelling and simulation of deflection mechanism in rock drilling processing
Authors: Liu Zhong , Yang Neng , Xiong Zhonggang , Huo Jiabo , Wang Hanying
Published: June 2021

With the development of social economy, hydraulic drilling machine has been widely used in the tunnel bridge, water conservancy projects and mining. In the process of construction, the drill rod of the hydraulic rock borer in drilling perforating process will produce deviation. It is often caused by the drilling efficiency and reduces the drilling hole scrap, seriously hindered the development of construction technology of drilling and blasting. Through the hydraulic drilling machine drill rod in the drilling cutting process of force analysis, drill rod in horizontal and vertical direction of the mechanical model are established. The relationship between the drill rod force and deflection of drilling in the drilling process is derived. At the same time, build ADAMS mechanical model, and the drilling process is simulated to find the relationship between the depth of drilling and the offset and offset angle. On this basis, the mechanical mechanism of borehole deviation of hydraulic rock drill is clarified, which provides a theoretical basis for the hydraulic rock drill hole deviations.
Application of biosensors based on nanomaterials in cancer cell detection
Authors: Zhang Yizhou , Lyu Hongling
Published: June 2021

Cancer, killing millions of people every year, is the most serious disease in the world. The survival of cancer patients is closely related to the diagnosis of cancer cells. Therefore, in the early stage of cancer, the detection of cancer biomarkers from cellular level is of great significance to improve the survival rate of cancer patients. Nanomaterials-based biosensors play the increasingly important role in the treatment of cancer, owing to their ultra-high sensitivity and high selectivity. Nowadays, it is widely used in the detection of cancer cells to provide reference for cancer treatment. Herein, the present minireview summarizes application of nanomaterials-based biosensors for the detection of cancer cells, such as colorimetric biosensors, fluorescence biosensors, surface-enhanced Raman scattering (SERS) biosensors, electrochemical biosensors and other types of biosensors. We further introduce the construction principle of these biosensing methods, and compare the advantages of these biosensors in detecting cancer cells.
Research on Usability of the Toolbar of Teaching Interactive Smart Tablet
Authors: Li Jialin , Wang Junfeng , Hao Pingting
Published: June 2021

The work aims to find out the usability problems in the design of the toolbar of teaching interactive smart tablet, and provide an improvement basis and direction for improving the user experience of the teaching interactive smart tablet. Usability testing and user interview were used to research the toolbar of Seewo teaching interactive smart tablet. Quantitative analysis of task completion time, task success level and task completion efficiency were measured in usability testing. The thesis combines the results of user interviews with the results of usability testing to find out the specific factors that affect the usability of the toolbar of teaching interaction smart tablet. The icon design of the toolbar of teaching interactive smart tablet has a great impact on usability. The hiding of frequently used functions may make it difficult for users to find them. The larger screen makes it difficult to find icons outside the field of view. The usability of interactive smart tablet can be improved by improving icon recognition, optimizing common interactive processes, and setting important functions in the best visual field.
Study on band gap properties of asymmetric locally resonant complex phononic crystals
Authors: Zhao Yingchao , Yang Xiaodong
Published: June 2021

In this paper, the band structure and transmission characteristics of asymmetric locally resonant complex phononic crystals are studied. Based on the Bragg band gap mechanism, an asymmetric local resonance element was designed and the structural parameters were optimized to obtain a wide band gap. The results show that the range of the first complete band gap is obviously affected by the size of the scatterer, the radius and height of the locally resonant cylinder and the position of the cylinder. At the same time, the transmission characteristics of the 10*10 periodic arrangement structure are calculated to verify the accuracy of the energy band structure.
Bowl Surface Laser Forming Process of Stainless Steel Composite Plate
Authors: Wang Xiaogang , Shi Yongjun , Guo Yankuo
Published: June 2021

In this paper, the three-dimensional bowl surface was obtained by reasonably planning the radial heating path by taking the laser as the heat source and the stainless steel composite plate (06Cr19Ni10/1Cr17Mn6Ni5N/06Cr19Ni10) as the research object, and the forming process of the three-dimensional bowl surface was studied. It was found that the target surface bending forming obtained by inside-outside symmetric scanning strategy (Strategy d) had the highest accuracy. The plate deformation increased with the increase of laser power (P), increased then decreased with the increase of heating line length (L), and decreased with the increase of scanning speed (V). Moreover, the deformation was approximately linear with the number of repeated heating (N), with the optimal process conditions of P = 500W, V = 10 mm/s, L = 20 mm, N = 7. A three-dimensional thermodynamic coupling model of a three-layer composite plate was established and verified experimentally.
A small displacement torsor (SDT)-based haptic rendering model for assembly of bolted joints
Authors: Yong-Peng Yu , De-Jian Xu
Published: June 2021

Haptic interaction technology is increasingly used in virtual assembly training, assembly path planning, teleoperation assembly and other fields. Obviously, the key issue of haptic interaction technology is the realistic haptic rendering models. This paper proposes a haptic rendering model based on small displacement torsor (SDT) for bolt assembly. For the first time, geometrical errors of parts are considered in the haptic rendering model of bolt assembly, which can improve the fidelity. The comparative experiment proves that the haptic rendering model proposed in this paper is more familiar to the actual assembly than the existing model.
Modeling and Simulation of Vehicle Handling Stability Control Based on Tire Pressure
Authors: Bi-bao Guo , Tao Fu
Published: June 2021

In order to study the influence of tire pressure change on the control of vehicle handling stability, the seven-degree-of-freedom theoretical model of automobile dynamics and tire theoretical model considering tire pressure were established. Considering the double lane conditions, the control stability of automobile is simulated, and the influence of tire pressure change on the control stability of automobile is analyzed. The simulation results show that when the tire pressure is too high or too small, the yaw rate of the vehicle in the process of high speed steering cannot be stable, which reduces the vehicle handling stability.
Design of motor online monitoring system based on ARM
Authors: Zhai Yuyi , Jiang Houyong , Liu Yunjia , Jiang Tao , Wang Le
Published: June 2021

In order to monitor the operation status of motors accurately in real time, and realize the early warning of abnormal operation of motors, a motor online monitoring system based on ARM is designed. The system uses STM32F103ZET6 microcontroller based on ARM Cortex–M3 core as the control core to monitor the motor temperature, vibration, environmental temperature and humidity and other related parameters, which communicates with the upper computer through wireless transmission, and the upper computer completes data display, storage, processing and alarm. The results show that the motor online monitoring system based has the advantages of strong real-time performance, high measurement accuracy, high stability and long transmission distance.
Design of a General Monitoring Host Machine for Railway Trackside Equipment
Authors: Shi Long , Ma Junjie , Guo Haiwen
Published: June 2021

A large number of infrastructure and equipment are distributed along the railway, which will directly affect the safety and efficiency of railway transportation. In this paper, a general monitoring host machine for railway trackside equipment is designed to realize the power supply, automatic networking, logic operation centralized management, data collection, storage and processing of trackside equipment monitoring. The host machine consists of a CPU board, a interface board, a power board, several PLC (Power Line Carrier) communication boards and isolation transformers. It supports a variety of monitoring applications, and covers almost all monitoring requirements of trackside equipment. Based on the monitoring host machine, a monitoring system for trackside equipment of track circuit system is developed.
MLAF: Multi-Level Attention Fused Model for Sentence Similarity Measurement
Authors: Chen Mengya , Sun Xiaoqi
Published: June 2021

Semantic textual similarity measurement is an essential task in text mining and natural language processing, which has profound research value. Recent LSTM-based methods have achieved attractive success by modelling sentences as fixed-length vectors. However, since the LSTM network can only extract the semantic information of sentences sequentially, the longterm dependency of sentences cannot be efficiently captured when the sequence length is long. Moreover, current models treat each syntactic component in the sentence equally, while the effects of different syntactic elements to the sentence meaning expression are different. Generally, nouns, verbs, and adjectives contribute more than prepositions and conjunctions to the semantic meaning of the sentence. In this paper, we propose a multi-level attention fused (MLAF) model, which correlates self-attention and word attention with sentence representations, extracting the semantic information of sentences from different levels. The self-attention supplements sequential operations to model long-term dependency of sentences. The word attention built upon raw sentence highlights the vital syntactic components of sentences. Experiments on different datasets demonstrate that the proposed MLAF model has achieved significant improvements over baselines.
High absorption efficiency of WS2/CNTS hybrids with conductive network for high performance EMI shielding
Authors: Wang H H , Zhang D Q , Zhang H B , Liu T T , Xu J Y , Cao M S
Published: June 2021

In order to reduce the environmental pollution caused by the secondary reflection of electromagnetic interference (EMI) shielding materials, the WS2/CNTs hybrids with high absorption efficiency were successfully prepared by using a one-step hydrothermal method. The WS2/CNTs heterostructure, which combines the unique excellent dielectric properties of WS2 with the high conductivity of CNTs, promotes the effective absorption and reflection of EMW. The excellent EMI shielding performance of 5WS2/CNTs-25 can reach up to 27.8 dB, which was analyzed by the dielectric properties of the WS2/CNTs hybrids. The conductive network composed of CNTs makes the multiple reflection and absorption of EMW, which makes the WS2/CNTs hybrids promising candidates for the field of EMI shielding.