bluuebunny/crossref_metadata_2025 huggingface dataset:
Convenient Power Supply Scheme Design for Remote Areas
Authors: Gong P , Hu P T , Zhu Y Q , Xia R H
Published: June 2021

At present, there are still a large number of people worldwide without electricity in remote villages. Electricity supply is one of the important conditions restricting the development of remote areas. In order to solve the power supply problem in these remote areas, this paper proposes a convenient power supply scheme. It adopts modular, flexibly configurable independent power supply based on renewable energy power generation technology, and is equipped with a backup power generation device based on human or animal power to ensure a certain degree of power supply reliability. Use easy-to-implement power supply equipment configuration and installation methods to achieve convenient layout of the power supply system. The above power supply scheme was evaluated in terms of technical feasibility, economy and social significance. Introduction
Design of real time system to measure the voltage signal in high voltage power supply
Authors: Li Zelin , Pan Gaofeng
Published: June 2021

The output voltage signals should be measured in real-time, and it is sent to a control system for feedback control and protection in the high-voltage power supply with high-voltage, strong magnetic field, or strong power condition. In order to obtain a stable output voltage and a rapid response of the protection in the high-voltage power supply system, the measurement of the voltage signal needs to meet three requirements: response in real-time, accurate, and high isolation. Using the voltage-to-frequency (V/F) converter AD650 to transmit the analog signals as frequency form through the digital optical fiber is the best mode to measuring the signals with high precision, real-time, long-distance, and high isolation. The composition and principle of the real-time voltage measuring device are described in this paper. The design of the hardware and the parameters are analyzed and discussed in detail. The experimental results show that the circuit structure based on the AD650 chip is simple. The optical fiber transmission can achieve high isolation and high accuracy (better than 0.1%). The low response time (under 30us) can meet the requirements of the real-time voltage signal measurement system. The signal will not be affected by the high electromagnetic field in the transmission process. The measurement system has been applied in the high voltage power supply with excellent linearity and high isolation.
Impact of Phase Locked Loop on Commutation Failure in LCC-HVDC
Authors: Tang Peiyuan , Yuan Xiaoming , Lu Jun
Published: June 2021

Besides the DC faults, AC faults and faults in converter, the dynamic process of control system has its influence on commutation failure. As an important element in LCC-HVDC control system, PLL provides the reference phase of receiving end power system for valve control system. When there is a difference between the real phase of receiving end power system and the output from PLL, control system cannot adjust extinction angle accurately. In this paper, the function of PLL in HVDC control system and the characteristic of PLL’s tracking process are analysed. Then the influence of the phase error caused by PLL’s tracking process on the extinction angle is discussed. At last, a detailed LCC-HVDC model is used to prove the impact of PLL’s dynamic process on commutation failure and test the influence of PLL with different parameters on commutation failure.
Current Measurement for Curved Conductor based on 3-D Coreless TMR Sensor Array
Authors: Guo Chunxian , Chen Lin , Zhang Huaiqing
Published: June 2021

Magnetic sensor arrays have been widely used in current measurement due to their advantages of small size, low power consumption, high sensitivity, wide bandwidth, and large dynamic range. However, researches in recent years all assume that the conductor is long-straight, while in actual engineering the conductor is usually curved. And the error introduced by curvature has not been searched until now. In this paper, a correction method based on circular 3D magnetic sensors array is proposed. The simulation results show theoretically that the method can greatly reduce the error. 3-D tunnel magnetoresistance (TMR) chip is selected as the magnetic sensors of the circular array in laboratory experiment, and the experiment errors can be reduced to around 1%. The simulation and experiment results verify that the correction method can improve the accuracy of the current measurement.
An arc contacts life assessment method based on dynamic resistance measurement and bp neural network
Authors: Chen Bangfa , Chen Xianxi , Diao Muxin , Xiao Guangyu , Yan Jing , Wang Zhenxing
Published: June 2021

Arc contacts ablation of high voltage SF6 circuit breaker will cause potential problems for safe operation of the grid. In view of the difficulty of predicting arc contacts life by existing methods, an arc contacts life assessment method based on dynamic contact resistance and BP neural network is proposed. The dynamic contact resistance-travel curve is obtained from the high-current ablation experiments, from which the data characterizing the arc contacts state is extracted as samples to train the neural model. The model is optimized by k-fold cross-validation method, which is finally validated by experimental results. The results show that the arc contacts life prediction value agrees well with the experimental value, which means that the BP neural network can effectively predict the arc contacts life and provide a basis for decision making for arc contacts overhaul and replacement.
Simulation and analysis on peak load regulation of office and living parks
Authors: Jin Feng , Kang Li , Liang Jishen
Published: June 2021

With the rapid economic development and the rapid increase in human living demand, the load power is constantly increasing, and the range of change is also increasing substantially. The peak-valley difference of daily load is increasing, which brings challenges to the peak-shaving of the power grid. The microgrid can not only supply sufficient power to the load, but also track part load changes, and has good economic benefits. Due to both of the variety of load types and the capacities of loads, the problem of peak shaving in the microgrid has also emerged. Using “source load” peak shaving to relieve peak shaving pressure is a good approach. This paper takes the minimum load fluctuation rate as the objective function, and uses the improved particle swarm optimization algorithm to simulate the peak load regulation in office and living parks. The results show that the “source load” peak shaving can make the load curve smoother. It is effective for “source load” to participate in peak shaving.
The Impact of Voltage Stability Constraint L-Index on Power System Optimization Base on Interior Point Algorithm by Considering the Integration of Renewable Energy
Authors: Nou Pheakna , Zhang Yiyi , Yang Yude
Published: June 2021

Renewable energy (RE) generation including wind and solar farms has experienced significant growth due to the challenge of climate and energy crisis. High penetration of RE affects system stability and generation cost optimization. In this paper, voltage stability L-index is proposed as the constraint of the primal-dual interior point method for optimal power flow by considering the integration of wind and photovoltaic cell power on system. L-index is used in this study to indicate the voltage security while renewable energy is prefixed into power system to build a new (REL-OPF) formulation that can consider the voltage stability margin and generation cost of the power grid. Weibull and Beta probability density functions are applied to determine the outputs of wind and photovoltaic power generation respectively. This model has the advantage that there is no need to calculate the critical point and could obtain the demanded voltage security level by adjusting the upper limits of indicator L constraints. The optimal solution can concurrently satisfy both the voltage security and the economical demand for power systems. The overall problem is simulated under coding written in MATLAB environment. The results obtained from regulating the upper limit of voltage stability constraint on IEEE30-bus has shown that the attention of RE generations into the system leads the fuel cost objective to decrease randomly as well as enlarge the distance of stability to a critical point with faster convergence.
Harmonic analysis of AC drive double PWM back to back network side
Authors: Dong Yijun , Yang Kai , Wang Jizhong
Published: June 2021

Aiming at the problem of harmonic pollution in the control system of large-scale steel rolling equipment in metallurgical plant, the mechanism of harmonic generation in AC-AC frequency conversion and AC-DC-AC variable-frequency speed regulation system is analyzed, and a double PWM back-to-back AC speed regulation system is proposed. This system can not only realize the regeneration energy of frequency converter, but also reduce the harmonic wave, and greatly improve the power factor of the system. Finally, through MATLAB simulation, the harmonic of AC-AC frequency conversion and AC-DC-AC variable-frequency speed regulation system is analyzed, and compared with PWM back-to-back AC speed regulation system, the superiority, effectiveness and feasibility of PWM back-to-back AC speed regulation system design for large-scale AC drive device control are proved.
Offline Measurement of Induction Motor Rotor Time Constant Based on Least Squares Algorithm
Authors: Cai Meidong , Zhao Yun , Nie Yaping , Liao Zhengbin , Wang Zefei
Published: June 2021

In order to solve the problems of disturbance and error accumulation in the traditional off-line strategy of rotor time constant, this paper optimizes the off-line measurement method of rotor time constant of induction motor. The off-line measurement method of rotor time constant based on recursive least squares (RLS) algorithm is analyzed in detail. Through the static characteristics of induction motor, the mathematical model of induction motor is simplified, and then the linear model of RLS algorithm is derived. The simulation results show that the rotor time constant measured by the least square method is more stable than that measured by the conventional method, which proves the practicability of the off-line measurement method. Finally, the error analysis of the main factors affecting the off-line measurement results of the rotor time constant based on the least square algorithm is given.
Loss Study of Dual Stator Low Speed High Torque Synchronous Motor with Hybrid Rotor
Authors: Fu Zongkun , Zhang Fengge , Zhang Zhaoyu , Jin Shi
Published: June 2021

Low speed and high torque machines are widely used in industrial production, oilfield mining, wind power generation, etc. Low speed high torque motors have large internal space, in order to make full use of internal space this paper proposes a dual stator low speed high torque synchronous motor. The rotor adopts a surface-mounted permanent magnet rotor structure on one side, and a spliced reluctance rotor structure on the other side. A magnetic ring is added in the middle to make permanent magnet and magnetic resistance independent of each other. The motor has a special structure, and the loss distribution is different from that of a normal motor. The loss will affect the performance of the motor. This paper establishes the iron loss model considering the effects of alternating magnetic field, rotating magnetic field, and harmonics. Considering the influence of temperature on copper loss. Then establish a mathematical model of core loss and copper loss. Then studying the motor iron loss and copper loss distribution characteristics. Finally, the results are compared with the finite element method (FEM) to verify the effectiveness of the loss calculation in the paper.
Electronic and structural properties in nanocluster Al
n

−

x
Ni
x
Authors: Blanco J , Guevara U , Lozada R , Castro O
Published: June 2021

In this paper, we study electronic isosurfaces and structural properties in nanoclusters Al
n

−

x
Ni
x
using Density Functional Theory, with the Local Density Approximation; the density of state, the highest occupied molecular orbital and lowest unoccupied molecular orbital were determined for different structures, obtaining different values of the energies. We have obtained evidence of a contribution of d orbitals for pure Ni nanoclusters and Al-Ni nanoclusters. In addition, an overlapping of the sp orbitals is evident. We also determined that the structure with the greatest binding energy corresponded to Al 10, with a D 2

h
symmetry, and the structure with the minimum binding energy corresponded to Ni 20, with a C 2

v
symmetry.
Thermodynamic stability of gilded copper and pigments at high relative humidity and at environmental conditions of Lima, Perú
Authors: Alviz-Meza A , Rodríguez-Reyes J C F , Chacaliaza J A
Published: June 2021

Cultural heritage materials are affected by diverse environmental agents such as humidity, temperature, and pollution. This work focuses on studying the thermodynamic stability of Peruvian heritage materials such as gilded coppers and pigments within two scenarios: one under ambient conditions and the other under accelerated conditions established by the ASTM D 2247 standard. In both cases, the HSC Chemistry 6 software was implemented. The general results obtained for gilded coppers showed that by varying the relative humidity from 75% and 14 °C to 80% and 26 °C, the corrosion products move from CuO to Cu(OH)2. In addition, to Cu2Cl(OH)3 -atacamite- in the presence of chlorin. On the other hand, for hematite (Fe3O2), vermilion (HgS), and Minium (Pb3O4) pigments, we found that at ambient conditions, with NO2and SO2, they give rise to goethite (FeO(OH)), mercury sulfate (HgSO4) and lead nitrate (Pb(NO)3), respectively. These changes also modify the natural colour of pigments, where goethite gives rise to a brownish red, mercury sulfate is colorless and lead nitrate is white. This paper is a quick theoretical way to understand how cultural heritage materials can physically degrade. Future experiment trials will contribute to set strategies towards the correct management of these heritage collections.
Analysis of the titanium ions concentration implanted in low alloy steel
Authors: Calero C A , Chacón J L , Niño E D V
Published: June 2021

In the surface modification processes obtained by high voltage electric discharges and cathodic arc at low pressures its of great interest to estimate the concentration of ions that are implanted on the surfaces of metallic substrates. The employment of computational tools to estimate the concentrations of implanted ions on the surface of materials as a function of the depth allows to optimize the experimental processes reducing costs and time. In the present research, a software that simulates the mobility, stopping and range of ions in matter by means of the Monte Carlo method is used, in order to obtain the ratio between the concentration and the dose of ions regarding to depth in a titanium ion implantation process on the surface of chromium molybdenum low alloy carbon steel; then, using experimental parameters, the implantation dose is calculated and an estimated profile of ion concentration is obtained as a function of the depth. The results showed that titanium ions implanted at 10 KV for 5 minutes and 10 minutes had projected ion ranges until depths of 250 Å and the highest concentration is located around 50 Å; the concentration of the implanted ions increases with the exposure time of the surface because the implantation dose is proportional to the discharge time. Furthermore, it is observed that the location of the highest concentration region and the range of the implanted ions is invariant.
Simulation of a full-scale activated sludge reactor: an approach to airflow rate optimization
Authors: Cueto D C , Alviz-Meza A , Colina J
Published: June 2021

Wastewater systems are high-energy consuming processes that discharge considerable amounts of pollutants into aquatic ecosystems, thus requiring appropriate optimization. Therefore, a full-scale activated sludge process was studied in this work through mathematical modeling of heterotrophic and nitrifying microorganisms. The airflow rate was introduced as the controlling parameter to accomplish the degradation of pollutants. Moreover, a sensitivity analysis was performed to determine the most sensible parameters that should be evaluated through further experiments, aiming to improve the model. The obtained results indicated that readily biological oxygen demand degradation and the oxidation of ammonia to nitrite could be achieved with an airflow rate of 35 m 3 air d -1. The sensitivity analysis showed that heterotrophic kinetic parameters and oxygen mass transfer coefficient through diffusers are the most sensitive to the system. These results also proved that the air-diffusing systems can work at 0.3% of their maximum capacity to accomplish degradation. Future studies should consider other oxygen-consuming variables.
Physical – mathematical model to determine the structural efficiency of sections shaped as ellipses and parallelograms when used in reinforced concrete columns
Authors: Márquez Peñaranda J F , Vergel Ortega M , Gallardo Pérez H J
Published: June 2021

Current practice of structural design of reinforced concrete columns uses mainly rectangular and circular sections. Among other reasons, this preference is linked to its ease of construction and spatial efficiency, and the historical inertia of civil works processes. Nowadays, modern design and construction techniques make possible to study the structural beahviour of sections distinctively shaped. If typical sections are extended from circular to elliptical and from rectangular to parallelogram shaped, it is possible to compute mathematical and physical parameters needed for the structural analysis. This work presents a physical–mathematical model to determine the structural efficiency in terms of relative strength and stiffness of sections shaped as ellipses and parallelograms when used in reinforced concrete columns. To solve the model, a Matlab® code for drawing the column interaction diagram of each studied section was written. Each diagram describes, in terms of mechanical physics, the relation between the uniaxial bending and the compression load that defines safety conditions as a mathematical limiting curve. The governing equation has the form P(m, g)=f(M(m, g) in which P describes the axial load strength function, M the bending moment strength function, m the material properties, and g the geometrical characteristics function. Structural efficiency has been expressed as the relative behaviour of each section with respect to comparable rectangular sections. To obtain the results of the model, a Matlab® code was written.
Estimation of greenhouse gas emissions in civil construction for a modular construction on the campus of the Federal University of Rio de Janeiro, Brazil
Authors: Ribeiro A A , Guimarães C S
Published: June 2021

The civil construction industry is recognized as one of the activities with the greatest environmental impact on the planet, in addition to being responsible for about 10% to 20% of emissions in the extraction of raw materials and manufacture of products for this segment. The main objective of this work was to estimate greenhouse gas emissions for the construction of an administrative building at the Federal University of Rio de Janeiro, Brazil, using the modular constructive method. The methodology used to inventory emissions was structured in the Brazilian greenhouse gas protocol program, the method most used worldwide by companies and governments for conducting greenhouse gas inventories. The research was also developed by simulating its construction by the “Conventional” method using construction materials, a source of great relevance in the literature. Based on the results of the inventory, the total greenhouse gas emission was estimated at 462.90 tCO 2e for the construction of the project, with a built area of 620.03 m 2, which resulted in the emission of 0.75 tCO 2e/m 2 of built area. Comparatively, this constructive method presented 22.12% less emissions when compared to the conventional method. This result allows, as a mitigation action, the possibility of proposing the implementation of new technologies and constructive methods that propitiate the reduction of greenhouse gas emissions.
Discussion on a boarding and installation system suitable for a movable wellhead platform
Authors: Wei XI
Published: June 2021

This paper introduces a boarding and installation system suitable for movable wellhead platform, and takes Offshore Oil 163 platform as an example, using finite element analysis and theoretical analysis, and verifies that the boarding system can provide safe and effective protection and support for the external riser.
Processing-based interactive installation art design—An example of a potentially hazardous odour identification device for the vision-impaired
Authors: Xue Dongchao
Published: June 2021

Nowadays, as cutting-edge technologies such as information technology and artificial intelligence continue to develop at a rapid pace, the integration of technology and art is being promoted, which has led to an unprecedented development of interactive installation art. Processing, as one of the open-source programming languages, plays an important role in the applications of the creation of dynamic visual art and interactive media art. This paper examines the application of Processing in interactive installation art, using the example of a potentially hazardous odour identification device for the vision-impaired, and explores the significance of programming techniques in interactive installation art, offering new ideas for the future direction of interactive installation art creation.
Research on Cycle Aging Characteristics of Lithium Iron Phosphate Batteries
Authors: Bai Dingsong , An Ziliang , Wang Ning , Liu Shaofeng , Yu Xintong
Published: June 2021

As for the BAK 18650 lithium iron phosphate battery, combining the standard GB/T31484-2015(China) and SAE J2288-1997(America), the lithium iron phosphate battery was subjected to 567 charge-discharge cycle experiments at room temperature of 25°C. The results show that the SOH of the battery is reduced to 80% after 240 cycle experiments, which meets the requirements of aging and decommissioning. Calendar aging has a side effect on the experiment. As for the aging process of the battery, it provides experimental support for improving the service life of the battery.
A numerical study of dendrite growth and microstructure transition in a non-equilibrium solidification
Authors: Ao Xiaohuia , Xia Huanxiong , Liu Jianhua , He QiYang , Lin Shengxiang
Published: June 2021

Controlling the thermal condition of a solidification process to obtain a desirable microstructure morphology and then prepare specific materials with excellent mechanical properties or special functions has been attracting many concerns, where the behavior of microstructure morphology transition, especially the columnar-to-equiaxed transition, is one of the most important fundamental issues. This paper introduced a kinetic model for dendrite growth with a large undercooling during a non-equilibrium solidification process using cellular automaton, in which the local thermodynamic equilibrium condition, non-equilibrium partitioned solute, curvature and interface energy anisotropy were considered. The growth rate of dendrite tip was numerically investigated by using the cellular automaton model, and the effects of temperature gradient and cooling rate on the growth rate and morphology features were found. By integrating the simulation results and analytical models, a new microstructure morphology transition criterion for the non-equilibrium solidification depending on the temperature gradient and cooling rate was proposed, in which both the planar-to-columnar and the columnar-to-equiaxed transition were presented.
A study of transducers with different monitoring surfaces for assessing the condition of cavitation activity
Authors: Yin Xiaoyu
Published: June 2021

Cavitation has received increasing attention worldwide due to its wide application in both medical and industry fields. The condition of cavitation activities takes a key role in its practical application, and it is passive cavitation detector (PCD) that is always used to detect real-time cavitation conditions. This paper reports the performance of a novel curved PCD that improved based on traditional PCD with a plane surface. It was found that the curved PCD had better sensitivity than the plane one and its optical operating area as well as critical performance points were also given. Based on this study, monitoring the performance of PCD can be improved for cavitation detection, especially in industrial fields that use stable cavitation technology.
Analysis of Low-Speed Diesel Engine Connecting Rod Made of AL360
Authors: Helal Wasim M. K. , Wenping Zhang , Xiaobo Li , Guixin Wang , Yanpan Su , guangku Chen
Published: June 2021

Connecting rod is one of the most important and critical components in an engine. The scientists should work on it in order to improve its performance. In the current study, in order to analyse the stress and deformation surrounding the connecting rod, the 3 D model is built. A connecting rod made of AL360 is investigated in this study. Stress distribution and deformation of a con-rod made of AL360 are carried out.
Calibration of Dual Industrial Robot System Based on Hand-Eye Calibration Algorithm
Authors: Jin Jingsen , Hao Weidong , Yang Daoguo , Tan Zhaoquan , Zheng Chuan
Published: June 2021

In order to improve the cladding efficiency and quality, the dual industrial robots are used to work together to achieve the task of repairing the industrial drill. However, the calibration accuracy of the base coordinates of the dual robot system is low, which directly affects the cladding quality. In order to solve this problem, a hand-eye calibration algorithm based on fixed calibration cone is proposed to calibrate the camera installed on the flange plate at the end of the machine arm, which improves the determination of the coordinate of the feature points of the calibration object. Based on the coordinate system of the calibration object as a link, the base coordinate relationship between the two robots with high accuracy is obtained.
Lightweight Optimization Design of a Light Electric Commercial Vehicle Frame
Authors: Zhang Jian , Ran Wei
Published: June 2021

Aiming at the weight problem of a light electric commercial vehicle, a lightweight optimization idea is proposed, which is based on the design of the frame structure made of TC4 titanium alloy. Taken the strength, stiffness and stability of the longitudinal beam as the boundary constraints, and the minimum mass of the frame longitudinal beam as the objective function, the mathematical model was established, and the longitudinal beam size was optimized by ant colony algorithm. The influence of different materials on the strength and stiffness of the frame was analyzed from the bending and torsion conditions. The finite element model of the frame before and after optimization was established in ANSYS, and the static conditions before and after optimization were compared and analyzed. The results show that: under the constraint conditions, the frame weight of TC4 material is reduced from 122kg before optimization to 103kg after optimization, which is 15.5% less than that before optimization, and the stress and deformation of the optimized frame meet the service conditions, which has great advantages for reducing the vehicle weight and realizing the lightweight purpose.
Lithography alignment method based on image rotation matching
Authors: Zhang Shaoyu , Zhao Lixin , He Yu
Published: June 2021

In this paper, we propose a lithography alignment method based on digital image processing technology for the proximity-contact lithography system. We perform image processing such as edge detection and image segmentation on the input image to obtain the edge image of the alignment mark; then we use straight line detection to obtain the angle of the image and rotate the image; finally, we use the template of the alignment mark to perform image matching to obtain the position of the alignment mark. The algorithm is tested on a proximity-contact lithography machine. The results have proved that the algorithm can use any shape of pattern for lithography alignment and therefore is highly adaptable and has a wide range of applications.
Numerical Study on Impact Resistance of Periodic Porous Structure
Authors: Mengting Bai
Published: June 2021

Based on the face centered cubic (FCC) and body centered cubic (BCC) structures, the effects of impact velocity on the deformation modes and stress-strain curves of periodic porous structures are studied by using the dynamic display nonlinear finite element method. The numerical simulation results show that under quasi-static loading, the overall deformation mode of face centered cubic structure presents a transverse “X” shape, while the overall uniform deformation of body centered cubic structure occurs. Under high speed loading, the two structures present layer by layer deformation. With the increase of loading speed, the stress plateau of the two structures increases, and the stress-strain curves fluctuate.
Simulation analysis of asynchronous induction type coil gun armature structure parameters
Authors: Zhang Pengxiang , Shu Tao , Shi Jianming
Published: June 2021

In this paper, the asynchronous induction coil gun is selected as the object of study, and its working principle is firstly briefly introduced, then the mathematical model is established by using the knowledge of electromagnetism, and then the MAXWELL component of ANSYS analysis software is used to simulate the velocity change curve of the projectile in the time domain under different conditions by combining static analysis and transient analysis, which reveals the relationship between the armature The relationship between structural parameters such as armature material, armature axial length, armature position, armature inner diameter and armature outer diameter and projectile end velocity is revealed, and the influence of several structural parameters on the acceleration performance of coil gun launcher is summarized and analyzed, and the optimized design principles of armature are summarized according to the obtained conclusions to provide theoretical references for practical applications.
Stability Improvement Methods and Application Progress of Metal-Organic Frameworks
Authors: Luo FuKang
Published: June 2021

Metal–organic frameworks (MOFs) are a kind of product produced with a combination of an inorganic metal center and a bridged organic ligand. Because of its porosity and high specific surface area, it has attracted much attention. However, due to the metal center and coordination bond is affected readily by other environmental factors, MOFs materials have relatively poor stability, which severely hampers its application in various fields. In this research, two ways of improving stability are summarized, one is via de novo synthesis, and the other is through post-synthetic modification to improve the stability of MOFs. Moreover, MOFs and its application fields, including gas separation and storage, catalysis, medicine, sensing, rechargeable batteries and capacitors production, are prospected.
Research on Stable Motion Control Method of Underwater Robot Based on Collaborative Filtering Technology
Authors: Peng Cheng
Published: June 2021

As countries in the world continue to deepen marine research and development and the need for national defense construction, unmanned underwater robots are playing an increasingly important role in scientific experiments, seabed oil and gas exploration and testing, and military affairs. The motion stability of underwater robots is the key to ensure the safe and reliable operation of underwater robots, and it is the main content of stability control research to make underwater robots return to the initial state of motion after being disturbed. Therefore, it becomes very important to study stability control methods. It’s necessary. This thesis first analyzes the motion characteristics of collaborative filtering technology in water, and establishes a dynamic model of an underwater robot system composed of main thrusters, double vertical thrusters and double-sided thrusters, and performs basic fluid flow for underwater robots.
Determination of Instability Critical Speed of Articulated Vehicle on Ramp Section Based on Response Surface Method
Authors: Xingju Cao
Published: June 2021

In order to improve the driving safety of vehicles on the ramp section, aiming at the lateral instability problems such as sideslip and rollover in the corner driving of semi-trailer trains, the six-axis articulated vehicle, which is the representative model of current highway freight transportation in China, is selected as the research object. The TruckSim simulation software is used to establish the vehicle dynamic model of nonlinear articulated vehicle, and the orthogonal simulation test of different loading quality and different road adhesion coefficient is designed. The vertical reaction force and lateral displacement of the wheel are taken as the evaluation indexes of vehicle sideslip and rollover, and the critical speed of instability under various road conditions is obtained. On the basis of surface function fitting, combined with the simulation experimental data, the response surface mathematical model of instability critical speed, road adhesion coefficient and loading quality is established. The comparison calculation shows that only 2.23% of the calculation error of the mathematical model reduces the error of the traditional model and improves the calculation accuracy of the model. The results show that the critical speed threshold of instability decreases with the increase of loading mass. With the increase of road adhesion coefficient, the threshold of instability critical speed increases. When the road adhesion coefficient reaches 0.6, the change of instability critical speed threshold tends to be steady. The research results can provide a reference for the evaluation of rollover and sideslip during the turning of articulated vehicle and the determination of anti-instability warning speed of articulated vehicle crossing the ramp section safely.
A novel approach to ensure the quality of 7075 aluminum alloy for green manufacturing
Authors: Yang Chun-Ming , Wei Wei , Chen Chuanying , Deng Wenting
Published: June 2021

With the rapid development of industrial technology, the most of the traditional industrial materials have been unable to meet the needs of current industry. Aluminum alloys is one of the most popular nonferrous metal materials used in industry. Among them, 7075 aluminum alloy is common applied in aerospace and marine plates because of its corrosion resistance and high strength. To ensure the production quality of 7075 aluminum alloy, reduce the waste of resources, and realize green manufacturing, this paper proposes a product quality inspection method by combining fuzzy Six Sigma process capability index and fuzzy axiom design for the supplier selection in aluminum alloy industry. A case study in Guangdong Province is used to demonstrate the effectiveness and feasibility of the proposed method.
Analysis on prefabricated construction technology of residence
Authors: Ting OuYang
Published: June 2021

After going through the initial, sustainable development and low tide stages, prefabricated buildings have ushered in a new development stage. In this paper, the development history, characteristics and advantages of prefabricated buildings are briefly summarized, and combined with the current construction technical points of residential prefabricated buildings, the key parts that construction enterprises should focus on in prefabricated construction are emphasized. At the end of this article, measures to improve the quality of prefabricated buildings are proposed from the macro perspective of the social environment and the micro perspective of the enterprise’s own development, so as to make a positive outlook for the development prospects of residential prefabricated construction.
Construction of BMP Education Reform Model Based on Multi-Element Information for Automation Teaching System
Authors: Huo Yan , Feng Li
Published: June 2021

With the arrival of the fourth industrial revolution, modern society is accelerating into the era of full intelligence automation. According to the requirements of new engineering construction, guided by the needs of advanced industry and economic development, combining theory education with practice training, a talent education model with general higher education and application-oriented teaching is constructed in this paper. The dynamic model is based on multi-elements including brain training, morality cultivation and practice improvement (BMP). The BMP model for automation teaching system combines the three elements to highlight the characteristics of modern application-oriented professional education, and provide reference for professional education system of automation technology.
Critical Speed Analysis of Rotor System of Sealing Machine
Authors: Gongwei GE , Huiliang Dai , Yitian Peng
Published: June 2021

The sealing machine is the key part of the copper pen tip processing machine, and its working stability will have a direct impact on the processing quality of the pen tip. Taking copper pen tip desktop processing equipment for an example, to improve the quality of pen tip, the modal analysis was carried out on the system by large-scale finite element analysis software ANSYS. The modal parameters of the rotor system were calculated, and through the Campbell diagram, the critical speeds of the system were obtained. Finally, the critical speed under different structural parameters is obtained. By analyzing data, the critical speed of the system is negatively correlated with the bearing spacing, and positively correlated with the diameter of the long shaft section, and independent of the bearing stiffness. The analysis results provide a theoretical basis for the optimization design of structural parameters of the system and the design of the maximum working speed, which also has certain reference value for the research and design of copper pen tip desktop processing equipment in China.
Design and Research of an Intelligent Medicine Box
Authors: Li Jiteng , Wang Luping , Qiu Jiyuan
Published: June 2021

In order to solve these problems, such as forgetting to take medicine, wrong dosage or type of medicine, an intelligent medicine box is designed. The intelligent medicine box is composed of a piston dispensing mechanism, a platform moving mechanism and a main body mechanism, etc. Close cooperation between various parts, realize the functions of storing medicines, automatically dispensing medicines, intelligent reminders, intelligent detection and intelligent sterilization. Through the simulation in solidworks, the mechanical performance simulation analysis. The results show that the deformation of the crank is very small during the whole process of dispensing medicines, there is no concentrated stress, and it has no effect on the dispensing efficiency during the dispensing process. The designed intelligent medicine box is not only for the elderly, but also suitable for all kinds of people. It can promptly remind patients to take drugs, reduce the occurrence of problems such as wrong medication and forgetting to take drugs. It is user-friendly in design, simple and convenient to operate, helps smart medical treatment, eases the pressure of medical care, and has good market application value.
Influence of impeller clearance structure on volume loss of centrifugal pump
Authors: Xiaolang Lu , Xiang Chen , Fukang Fu , Wei Jiang , Shuang Li
Published: June 2021

In this paper, the three-dimensional full flow field model of double volute structure centrifugal pump is established, and the ring seal, teeth seal and interlocking seal structures are set up. The K-e turbulence model of CFX software is used to simulate and analyse the fluid flow state at the gap of different mouth ring structures of centrifugal pump. The results show that the staggered ring structure can effectively reduce the leakage and improve the volumetric efficiency of centrifugal pump.
Research of Vibration Characteristics of Ship Propeller-shaft Longitudinal Two-stage Vibration Isolation System
Authors: Quanchao Li , Rui Zhou
Published: June 2021

Aiming at the vibration control problem of ship propeller-shaft system, this paper put forward a design approach of ship propeller-shaft longitudinal two-stage vibration isolation system and its dynamic characteristics are studied. The vibration mathematical model of ship propeller-shaft longitudinal two-stage vibration isolation system is established. The influence of mass ratio, stiffness ratio and damping ratio of two-stage vibration isolation system is studied. The design is optimized taking a ship propeller-shaft system as an example. The results show that the ship propeller-shaft longitudinal two-stage vibration isolation system which is optimized has better isolation effect than the single-stage vibration isolation system. The research results have important reference value for ship propeller-shaft longitudinal vibration isolation design.
Research on Arrhythmia Classification Method Using Optimized Probabilistic Neural Network
Authors: Junkong Liu , Lili Li , Yipin Fang , Jinyu Su
Published: June 2021

Aiming at the classification difficulty of complex and diverse ECG signals, this paper proposes a feature extraction method based on standard deviation. This method solves the problems of multi-dimensional, diverse, high similarity and the difficulty in extracting main features effectively of ECG(electrocardiogram, ECG) signal features. In addition, this method overcomes the difficulty of low classification accuracy because of large differences in ECG signals of the same type among different patients. This paper adopts optimized probabilistic neural network methods to achieve automatic classification of arrhythmia. First, the standard deviation of the dimensions of each sampling point of the ECG signal would be calculated and sorted by size. Second, the first m dimensions as the feature dimensions of arrhythmia would be extracted. After that, the probabilistic neural network would be used to train and classify feature dimension data. Finally Bayesian Optimization(BO) method would be used to optimize the parameters globally. In the experiment of the MIT-BIH arrhythmia database, the arrhythmia data was divided into 5 categories and verified, experimental results show that the correct rate of classification of the arrhythmia data of patients reached 99.67%, which proved the effectiveness of the method in this paper.
Research on Automatic Positioning Control System of Riprap Barge
Authors: Hua Xiaotao , Liu Yan , Sun HaiYang
Published: June 2021

Based on the research of ship automatic positioning technology and deviation correction technology, combined with the gravel laying technology of single ridge subgrade bed of immersed tunnel, the control strategy of riprap barge is determined: ship automatic positioning technology based on tension control and rope length control. Combined with the gravel laying technology of single ridge subgrade bed and the control strategy of riprap barge, the algorithm of automatic positioning and moving of riprap barge is studied. Combined with the engineering practice, control strategy and control algorithm, the intelligent anchoring positioning control system is designed to realize the high-precision and fast intelligent displacement of gravel bed laying ship.
Safety Analysis of THAAD Anti-Missile System Launcher
Authors: Junhui Tang , Huiming Shen , Jintao Wang , Wenli Yu , Tao Wang , Guiyun Hang , Peng Wang
Published: June 2021

Safety analysis is a very important link in the assessment of damage effect before combat operations, and it is also the premise of war damage assessment of weapon targets. This paper takes the launcher of THAAD anti-missile system as the research object, analyzes the structure and functional characteristics of the launcher of THAAD anti-missile system based on literature, reconstructs the three-dimensional model of the launcher, classifies its damage grade, and defines the key vulnerable parts of the launcher. Taking the fragment detonation warhead as an example, the failure mode and damage grade of the key vulnerable parts under the action of fragments are analyzed, and the K and F damage tree models of the launcher of the THAAD anti-missile system are constructed, which provide reference for the security evaluation and research of the THAAD anti-missile system.
Structural Engineering Analysis for a Control Moment Gyroscope Framework
Authors: Xiu Tian , Yue-dong Lang , Xin-xiao Lai , Er-yong Hou
Published: June 2021

The framework structure of a control moment gyroscope (CMG) system was regard as a research object, which stiffness and vibration mode was analyzed by ANSYS finite element method software, so that its static and modal characteristics under a large load were obtained. And according to the analysis results, its structural optimization design was implemented to meet the requirements of structural characteristics in the frame system. The results of optimized analysis showed that the structure strength and dynamic characteristics were enhanced obviously, which verified the necessity and reasonability of engineering analysis for the structural design. Therefore, it can provide a theoretical basis for system design.
Research and application of the potential tapping method of single sand body in a high water cut period
Authors: Yao Yuqing
Published: June 2021

This paper studies the reservoir sedimentary system of an oilfield, grasps the origin and characteristics of sand development in narrow and small river channels, and uses the method of sandstone facies determination to track and predict sand bodies, and establishes the continuous distribution mode of channel sand bodies. On this basis, combined with the dynamic monitoring data, the type and potential of remaining oil in the oilfield are analyzed by using the dynamic analysis method, and five potential tapping directions centered on the channel sand body are determined. The practice shows that the remaining oil analysis based on the anatomy of single sand body should be paid more attention to in the exploration of potential in high water cut period. Combined with various technical means such as reinjection, encryption and orientation, the injection production relationship of single sand body should be improved and the field application has achieved good results.
Experimental study on the effect of stone powder content on the plastic shrinkage of self-compacting concrete at early age
Authors: Wang Hui , Bai Ziyun , Zhao Jiaxing , Li Kai
Published: June 2021

To investigate the effect of water-cement ratio and stone powder admixture on the plastic shrinkage performance of self-consolidated concrete by measuring the shrinkage deformation within 24 hours after casting through non-contact shrinkage test. The test shows that the larger the water-cement ratio and the higher the stone powder admixture, the larger the early-age shrinkage value; the early-age shrinkage growth rate is mainly affected by the water-cement ratio, and the early-age shrinkage growth rate tends to level off later for small water-cement ratio; the effect of stone powder admixture on different water-cement ratios is slightly different, and the increase effect of stone powder admixture on early-age shrinkage is more obvious under the high water-cement ratio condition.