bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation and Physical Experiment Study on Powder Metallurgy Preparation of Silicon Composite Powder
Authors: Jia Qian , Ding Zhaochong , Zhang Xiaona , Cao Xiaomeng , Teng Haitao , Li Yongjun
Published: March 2020

The compaction and sintering processes of multi-component silicon powders, including single-action die compaction, uniaxial hot pressing and bidirectional hot compaction, were numerically performed by FEM (finite element method) modelling. The relationships of initial packing structure, compaction method, pressing pressure and sintering temperature between overall relative densities of multi-component silicon components were systematically discussed and studied. Meanwhile, various macro- and microscopic properties of silicon composite powders were carefully characterized, such as overall and local relative density, local stress distributions and void filling behaviour. The results show that fully compacted silicon composite targets with low internal stress can be obtained by using uniaxial hot pressing or bidirectional hot compaction method. And the physical experiments were carried out to verify the accuracy of the simulation results.
Study on the Performance of Road Cement Stabilized Base Using Natural Graded Gravel
Authors: Yang Chenhui , Yang Jiaqi , Huo Zhiqiang , Yang Zhengxun
Published: March 2020

In order to alleviate the increasing supply shortage of building materials, this paper uses the method of comparative test to carry out a stability study of cement stabilized base with green cement bonded natural graded gravel on compressive strength, splitting strength, resilient modulus and other indicators. The research shows that the natural graded gravel, which is a kind of energy-saving and environmental natural building materials, has good road performance as a raw material for cement stabilized base with green cement binding. The green cement bonded base shows higher compressive strength, splitting strength and resilient modulus than those of ordinary Portland cement.
Optimization determination of three-dimensional solubility parameters of fluororubber F2603
Authors: Li Hongmei , Shi Xiaoqin , Feng Xuesong , Dong Liming
Published: March 2020

Turbidity titration experiment on fluororubber F2603 using a variety of good solvents and poor solvents, the minimum volume closure ellipsoidal fit is performed on the 48 cloud point data generated by KY (Kumar and Yildirim) first-order algorithm, thus determining the ellipsoid The ball center is a three-dimensional solubility parameter: δd=16.63(MPa)1/2; δp=11.25(MPa)1/2; δH=12.02(MPa)1/2, and the solubility parameter is 23.40(MPa)1/2.The reliability and accuracy of the fitting results are determined by the group contribution method, The solubility parameters have important guiding significance for selecting solvents with superior performance and determining better formulation design.
Research on Vibration Isolation Platform Based on Vibration Transfer Theory
Authors: Su Zhaobin , Zhang Yuting , Zheng Jianyi
Published: March 2020

Aiming at the interference problem of various vibration sources to laboratory precision instruments, combined with the theory of vibration transmission, the basic block design research based on large vibration isolation platform is proposed. Firstly, through the theoretical analysis of the vibration isolation platform, the transfer function of the vibration isolation effect with different damping ratios is obtained. Secondly, the parameter knowledge of the basic block model is analyzed, and the basic block is analyzed based on the analysis of the system resonance. Finite element analysis; finally, the vibration of the foundation and the basic block was measured by high-precision acceleration sensor. By analyzing the data, it was verified that the vibration isolation platform has obvious blocking effect on high-frequency vibration.
Determination of Arctiin in Fructus Arctii by Capillary Electrophoresis
Authors: Zhou Xiaojing , Liu Haixing , Wang Lintong
Published: March 2020

This paper investigated the determination of arctiin content in Fructus Arctii by high performance capillary electrophoresis (HPCE) method. The borax solution of 37.5 mmol concentration containing 12.5% methanol was chosen as buffer solution. The experiment was performed at a constant voltage of 16 kV and UV detection wavelength of 277 nm. The content of arctiin in Fructus Arctii was 26.45mg/g (RSD=3.34%) (n=7). The recovery was in the range of 87.6%-111.8% (n=5). This method is suitable for the detection of the content of arctiin in Fructus Arctii.
Feasibility Study on PRTV of Suppressing insulator Iron Cap from Corrosion
Authors: Tang Ping , Zhu Jun , Chen You , Wei Ming , Cao Xiaobin
Published: March 2020

UHVDC transmission line porcelain and glass insulator iron caps are seriously corroded, safe and effective anti-corrosion measures are of great significance for the stable operation of the power system. In order to determine the key parameters of PRTV spraying on the surface of insulator iron cap, a three-dimensional finite element model of insulator is established, and the test verified the feasibility of PRTV anti-corrosion of iron cap. The research results show that PRTV can effectively reduce the leakage current density of the insulator iron cap. PRTV can effectively prevent corrosion of the insulator iron cap, and can reduce the surface fouling speed of the insulator, improve the surface resistance of the insulator, and inhibit the insulator flash. The research results can provide reference for the research of anti-corrosion of insulator iron cap.
Calculation of Electrochemical Corrosion Rate at Elbow of Supercritical CO2 Pipeline
Authors: Chen Bin , Kang Qinghua , Ju Rongbin
Published: March 2020

Based on the CCUS project planned to run in a domestic oil field, the electrochemical corrosion at the bend of supercritical CO2 pipeline was studied by means of high-temperature and high-pressure reaction kettle hanging plate experiment, and the corrosion rate of X80 pipeline steel in unsaturated, saturated and supersaturated supercritical CO2 with water content was obtained. Then through COMSOL simulation of the corrosion rate of 90° bent pipe in the supercritical CO2 corrosion atmosphere, the maximum corrosion rate position of electrochemical corrosion generated under the action of flow accelerated corrosion (FAC) generated by supercritical CO2 fluid in the bent pipe was obtained, and corresponding anticorrosion Suggestions were put forward according to the research results.
Method of Tolerance Design and Verification of Parts Based on Follow-up Crankshaft Grinder with Following Double Grinding Wheel Frame
Authors: Fan Jinwei , Huo Leilei
Published: March 2020

Calculating the parameters of accuracy along each axis by the comprehensive geometric accuracy and then optimizing as well as assigning the accuracy, which is the cutting-edge way of accuracy design of machine tools. However, the guarantee of the comprehensive geometric accuracy of machine tools is ultimately to implement the tolerance of specific moving parts. In view of the present shortage about accuracy design of machine tools, this paper puts forward to a way to design and verifies the tolerance of movement parts based on the comprehensive geometry precision of K2-1080 Crankshaft Grinder with Following Double Grinding Wheel Frame.
Analysis of Electrostatic Driven Micromachined Gyroscope
Authors: Jiao Runyu , Luo Zhaomin , Wang Jianming , Xu Xingming
Published: March 2020

Micromechanical gyroscopes are an important inertial instrument used to measure the angular or angular acceleration of an object. China’s research in this field lags behind that of developed countries in the West. The research on the core components of high-performance micromachined gyroscopes is still in its infancy. In this paper, a fully symmetrical multi-ring vibration structure electrostatically driven micromachined gyroscope is proposed, which is studied from the theoretical basis, working principle, structural design, performance simulation, processing technology and device testing, including the following electrostatic drive micro Testing of mechanical resonant devices. The test methods of several main MEMS resonant devices are analyzed. Based on vector network analyzer, vacuum cavity, transimpedance amplifier and other equipment, the frequency sweep test is performed on the device, and the resonant frequency of the drive shaft is 23686.2z. The resonant frequency of the sensitive axis is obtained. For the 23980 Hz based on the principle of electrostatic regulation, a 2.5V electrostatic adjustment voltage is applied to the device, and the frequency cracking of the two modes is reduced from 293.75 Hz to 6.25 Hz, which improves the performance of the device.
Synthesis of zinc oxide nanorods with different aspect ratios by solvothermal method
Authors: Wan Lijuan , Yang Ming
Published: March 2020

The ZnOnanorods with different aspect ratios have been synthesized by solvothermal method. The as-prepared ZnOsampleswere characterized byBET surface area measurements, SEM and etc. By modulating the different reaction temperatures and the different precursors, the as-prepared ZnO samples with nanorods morphology and different radius were prepared and the influence of the reaction conditions are investigated. Also the different morphologies may influence the potential applications of the as-preparedZnO.
Facile synthesis of ternary oxide and the performance of photo-catalysis
Authors: Wan Lijuan , Yang Ming
Published: March 2020

Nano-structured Zn2GeO4 photocatalyst was prepared through solution phase route. The as-prepared products were characterized by Brunauer–Emmett–Teller (BET) surface area measurements and scanning electron microscopy (SEM). The experimental results revealed that for photo-degradation of MO, the nano-structured Zn2GeO4 samples with higher surface area have higher photocatalytic performance than bulk Zn2GeO4 synthesized through solid-state reaction.
A Study on Testing of Rubber Friction Coefficient and Its Wear Surface by UMT-2
Authors: Liu Wei , Zheng Yuqing , Wang Ting , Lv Lutao , Yang Zonglin
Published: March 2020

For some products as tire, shoes and other wear parts products, friction performance is a very important performance index. A series of theories had been put forward to study the friction properties. With the development of science, the method of rubber friction was more and more abundant, from the friction wear properties to the microstructure, as well as the simulation, all the friction performance of the study provided a reliable basis. UMT - 2 multifunctional friction and wear testing machine, friction properties of the rubber material to make relatively objective evaluation, can provide reliable basis for research on the properties of friction. Due to many factors influencing the rubber materials, rubber friction behaviour of the friction and wear mechanism of exploration would still need a lot of research work.
Experimental investigation on the dynamics of cathode spots in arc plasma descaling
Authors: Tang Zhongliang , Li Haibin , Liu Shulong , Liu Yi , Hu Jing
Published: March 2020

In the ferrous metallurgical industry, removal of the oxide layer on steel surface (i.e. descaling) with low pressure arc plasma is an environmentally friendly method. In this paper, high speed camera and oscilloscope were employed to diagnose the process of arc decaling. The evolution of cathode spots morphologies and the property of arc voltage fluctuations were investigated for different discharge conditions. The motion and lifetime of the cathode spots are affected obviously by discharge parameters such as pressure, electrode gap and arc current. The lifetime and velocity of the cathode spots are essentially depended on the properties of the substructure of the cathode spot. The fluctuations of arc voltage are directly associated with the dynamics of the cathode spots, and there are large voltage fluctuations for short spot lifetime, large velocity of the spots and poor conditions for spot ignition.
The Effect of Photoconductive Semiconductor Materials in Improving the Resolution of Femtosecond Streak Camera
Authors: Liu Xiaorong , Li Song
Published: March 2020

In this study, through the research on the effect of photoconductive semiconductor materials in improving the resolution of femtosecond streak camera, the effective value of applying photoconductive semiconductor materials to femtosecond streak camera is discussed and analyzed, and the effectiveness of photoconductive semiconductor materials in improving the resolution of femtosecond streak camera is verified. Method: In this study, first of all, the generation and recombination of carriers in semiconductors are studied. Solving the continuity equation is applied to further explore the law of the motion of carriers. Later, photoconductive semiconductor materials are used in the preparation of switching devices and scanning circuits. After that, the prepared circuit module is tested by dark current. The main purpose is to realize the resistance of the circuit switch in the intrinsic state and the dark state withstand voltage ability of the circuit switch. Results: It is found that the dark state withstand voltage of each switch can exceed 6000V. In addition, it is found that the current value of the switch under different light is different. When in the natural light, the current value is large. When it is in the state of shading, its current value is relatively small. The efficiency of all three switches is over 50%. The efficiency of nonlinear model is obviously higher than that of linear model, which can be more than 90%. By applying the semiconductor material to the femtosecond streak camera, the scanning circuit can be optimized effectively to meet the high standard requirements of the femtosecond streak camera for the scanning circuit, which has certain advantages, and has certain value and significance for improving the resolution of the second streak camera.
Effects of Alloying Elements on Mechanical and Electronic Properties of Cu by First-Principles Calculations
Authors: Peng Cheng , Zeng Lijuan , Huang Fuxiang , Zhong Mingjun , Liang Shuang , Ran Xiaojie , Zhou Lu
Published: March 2020

The effects of alloying elements (Mn, Cr, Sn, P, Be and Ti) on the mechanical and electronic properties of Cu have been investigated performing first-principles calculations. A supercell consisting of 107 Cu atoms and one solute atom is used. The calculated results show that the binding energy values of Cu107X alloys are negative, indicating they have thermodynamic stable structures. The ductility properties and hardness of Cu and Cu107X alloys are also determined based on the calculated elastic constants (cij’s). It is found that the ductility properties of Cu107X alloys decrease due to the addition of alloying elements, but they still exhibit plasticity. However, the Vickers hardness of Cu107X alloy is improved, and the Cu107Be has the largest calculated value of 5.62 GPa. In addition, the electrical conductivity of Cu107X alloy is reduced, among them, Cu107Be and Cu107Mn have relatively high electrical conductivity of 2.58 and 2.53*107 S/m, respectively.
Preparation and research of brush-coated solvent-free polyurethane anti-corrosion coatings
Authors: Han Zhongzhi , Shi Jiafeng , Ding Chao , Li Shi , Cui Cancan , Duan Shaoming , Wang Lei , Guo Xiaojun
Published: March 2020

In order to solve the problem of short gel time and difficulty in brushing of solvent-free polyurethane coatings, the coatings choose polyether polyester polyol and polyisocyanate prepolymer as the main film-forming materials, adding spherical ceramic powder to improve the wear resistance of the coating, combination of molecular sieve physical dehydration and oxazolidine chemical dehydration, effectively solves the problem of water sensitivity of paint, a solvent-free polyurethane anticorrosive coating for brush application was prepared. The coating also has good adhesion, excellent wear resistance and corrosion resistance.
Study on an angle measuring device based on mechanical gyroscope
Authors: Zhang Zilin , Zhao Huimin , Li Xiyuan , Zhao Xu , Sun Jingchao , Yan Zhou
Published: March 2020

The circular staggered magnetic field is studied and built. Then combining with the mechanical structure of the mechanical gyroscope, a tilt angle measurement instrument which cannot be interfered by the external conditions is designed. A stable working magnetic field is generated in the system itself. Based on the principle of electromagnetic induction, the tilt angle change is transformed into the electrical signal change output, and then the tilt angle is measured.
Analysis of Fatigue Fracture and Strength Improvement of Backup Rolls
Authors: Zhang Jiamin , Wang Xiaochen , Liu Huaqiang , Yang Quan , Xu Dong
Published: March 2020

As an important part of the cold rolling mill, the backup rolls are always in service under complicated stress conditions. Once the roll fails, it will bring huge economic losses. In this paper, the problem of fracture failure of the backup roll neck position in an 1150mm six-roll reversible cold rolling mill of a company is analyzed. The stress distribution of the barrels under working condition is calculated by the finite element software ABAQUS, and the stress value at the dangerous section of the backup roll is obtained. The fatigue strength safety factor of the backup roll is obtained by analytical calculation. Combined with the actual production situation, from the perspective of structure and size design, improved schemes can be proposed to improve the fatigue strength of the backup roll. This analysis can provide reference for related enterprises.
Analysis on calculating process of mechanical precision of devices on satellite
Authors: Xue Bijie , Zhang Lei , Zhong Hongxian , Jing Fa
Published: March 2020

With the gradual complication of the devices on satellite, the mechanical precision of some devices with accuracy requirements on satellite should be predicted after the assembly, in order to conduct the previous design of devices and accuracy assignment of satellite. This paper will discuss main factors which influence the mechanical precision of devices, process design and calculating method. And the position and orientation matrix is used to analyse the influence of error at each stage on mechanical precision of devices after installation. One thruster on satellite is chosen as an example to specify the calculating process and feasibility of this calculating method. This paper proves that the satellite structure assembly has a small impact on mechanical precision. The control method of mechanical precision is put forward at design stage and assembly stage of satellite, and the mechanical precision and error distribution method of devices on satellite is predicted through position and orientation matrix at previous work stage.
Research on Vibration Reduction Compatibility for Multiple Transportation Conditions
Authors: Xu Botao , Fang Zhikai , Liu Yugang , Liu Xingyue
Published: March 2020

Vibrations in the process of transportation are often neglected in product design. In order to avoid damage to acceleration sensitive equipment or components of spacecraft due to destructive transport load, vibration absorbers are usually installed in the container during spacecraft transportation. How to determine the vibration reduction scheme suitable for different payload weight has become the key point and technical difficulty in the design of vibration reduction in transportation. Aiming at this problem, the size and weight of the target product are analysed, and the vibration features of different sections of the satellite are analysed and tested. On this basis, a general vibration reduction subsystem of the container is designed, which is suitable for three kinds of satellite sections and four types of transportation conditions, and the loading distribution parameters are optimized. Transportation test data show that the vibration reduction effect of the new system for aerospace products meets the design requirements.
Exploration on Extracting Geometric Model by Topology Optimization Design
Authors: Miao Jiaqi
Published: March 2020

Topology optimization design is a way to achieve more efficient design with a minimal priori decision. However, due to the complexity of the solution obtained, topology optimization is usually limited to theoretical researches and can not be applied into actual manufacturing. As a new manufacturing method that is currently developing rapidly, additive manufacturing has made great progress in many fields. Additive manufacturing has fewer limitations on the shape and complexity of the design. And it is currently moving toward higher precision and larger dimensions. The combination of these two ways can solve the problem of topology optimization design well. However, the topology optimization design’s principle determines that it is difficult to transform into a 3D model that can be processed and manufactured pefectly. Based on the topology-optimized structure, this paper uses MATLAB to extract the geometric model and smooth it, which provides an effective method for extracting 3D models from topology optimization. Also, this paper puts forward an efficient method to optimize the structure and it gets a pretty good result in the simulation.
Study on the Reuse of Abandoned Shared Bicycle Materials
Authors: Shui Xingfei , Lu Xinhui , Lin Xinyu
Published: March 2020

The abandoned shared bicycle materials was redesigned and reused to manufacture fitness bikes, in basis of the analysis of its function and structure, to boost its recyclability. This work was referred from the mature re-manufacturing technology. The structure and dimensions including lever length, seat height and crank length of fitness bike were analyzed using ergonomics method.
Effect of Three Heat Treatments on High Temperature Oxidation Properties of GH4169 Alloy Produced by SLM Additive Technique
Authors: Liu Xuenan , Liu Siyuan , Feng Sengnan , Li Huixiang , Wang Yizhe , Gong Jianhong , Sun Hui
Published: March 2020

In this paper, GH4169 nickel-based superalloy molded samples produced by Selective Laser Melting (SLM) were subjected to aging treatment and solution and aging treatment to study the high temperature oxidation behavior under different heat treatments. It is found that the high temperature oxidation products of GH4169 samples produced by SLM is mainly Cr2O3. The alloy sample under heat treatment has a higher high temperature oxidation rate. The oxide film of GH4169 alloy sample treated by solution and aging treatment has a high forming speed, and the surface of the oxide film is continuous and dense, and the quality is the best, and the protection effect on the alloy matrix is the best.
One-Step Synthesis of Au Nanoplates with the Assistance of Formaldehyde
Authors: Xia Jing
Published: March 2020

In this work, a facile method has been developed to fabricate Au nanoplates in one step through heating formaldehyde and HAuCl4 aqueous solution. The obtained Au nanoplates are single crystal with an average edge length of approximately 160 nm. And the formation of plate-like Au nanostructures is because of the adsorption of formaldehyde on the surfaces of Au nanostructures, leading to a similar surface energy of {111} and {100} facets.
Exploration on the Structure Parameters of Nozzle-to-Throat Clearance in Vacuum Generator
Authors: Guo Xilong , Li Yong
Published: March 2020

Nozzle-to-throat clearance is one of the main factors affecting the injection coefficient of the vacuum generator. The increase of nozzle-to-throat clearance will lead to the aggrandizement of the annular duct area which the driving fluid passes, thereby amplifying the ejector flow rate of ejector tube and the injection coefficient. On the contrary, Keenan [1] obtained the result through the experiment that the injection coefficient decreased as nozzle-to-throat clearance increases, because the accretion in nozzle-to-throat clearance would increase the pressure of inlet plane of the mixing chamber, resulting in the decrease of the driving pressure difference of the driving fluid, hence the injection coefficient diminished. In this paper, the numerical simulation method is used to obtain the optimal nozzle-to-throat clearance parameter size.
Preparation of polyacrylic acid and its activation on macrophages
Authors: Zhou Mengmeng , Li Xin , Wang Zhengzheng , Zhou Haijun , Chen Xiaoqi , Yang Shulan , Li Yantao
Published: March 2020

With the rapid and efficient development of animal husbandry industry, intensive a nd large-scale has become the main body, and the corresponding use of vaccines and vaccine adjuvants has gradually increased. Polyacrylic acid has been widely used in vaccine adjuvants because of its safety and low toxicity. In this paper, polyacrylic acid was been prepared by aqueous solution polymerization, taking redox system as catalyst. The molecular structure of polymer was characterized by FT-IR. Viscosity average molecular weight was tested on a ubbelohde viscometer. Moreover, activation of polyacrylic acid on macrophages was analyzed by cell culture method. Results showed that the vaccine prepared by polyacrylic acid as adjuvant and chicken ovalbumin could stimulate macrophages to produce higher IL-1 β.
Research on Preparation Technology for Continuous Carbon Fiber Reinforced Printing Filaments
Authors: Bi Xiangjun , Tan Hongsheng , Li Zonghui , Li Yuqin , Liu Tengfei
Published: March 2020

Continuous carbon fiber reinforced thermoplastic composites with high mechanical strength can make up for the low-bearing faults of pure resin material and particle reinforced material. At the same time, the physical properties of fiber conduction can meet the structure damage detection and conductive functional requirements. It is seen as one of the advanced technology in thermoplastic 3D printing field. At present, the material has been gradually used in robot manufacturing, aerospace components manufacturing and so on. This paper introduces the preparation process of continuous fiber reinforced printing filaments and the characterization of mechanical properties, morphology and printing results. It points out that the printing filaments can meet the basic requirements of continuous fiber reinforced printing, which with high fiber orientation is affected by prepreg tension function. In addition, the small diameter filaments have obvious advantages in transportation, printing fabrications and printing effects. It is suggested that continuous fiber reinforced printing is suitable for choosing filaments with the diameter of 0.4mm or less.
The Static Characteristic Analysis on Key Components of Boring-milling Machining Center
Authors: Tao Lin , Zhao Yuan , Zhao Yue , Zhang Lili
Published: March 2020

Taking TH5650X50 Boring-milling Machining Center as the research object, analyze the static characteristics of the two key components of the milling system. Use finite element software to create 3D model of the two key components of the milling system and design the whole virtual assembly of milling system. Based on the theory of cutting deformation, consider the application of its forces and non-forces in the way of a remote payload and remote quality. The finite element model of spindle box-principle axis and crossbeam are obtained by circular grid division method, and all the parameters of the finite element model are solved by FFEPlus solver in Solidworks Simulation module. The study verifies the accuracy of the finite element mode, and obtains the deformation of the two key components under the most adverse conditions.
An Algorithm for Leakage Detection of the Heating Pipeline
Authors: Guo Huijie , Li Yulong , Yang Fan
Published: March 2020

The existing heating pipeline in our country has the serious problem of bubbling, dropping and leaking, which causes the huge waste of energy and the loss of pipeline investment. An algorithm for leakage detection of the heating pipeline is proposed to solve the difficult problem of heating pipeline leakage monitoring by establishing the background noise database, capturing effective noise signals, screening suspected leakage noise signals and recognizing the leakage noise signal with an advanced coarse-to-fine process. Once the pipeline leakage is detected, professionals will be informed to locate and repair the leakage point to minimize the impact of the accident. Meanwhile, the background noise database and the parameters of leak detection algorithm are updated by using false alarm signals, which can continuously improve the accuracy of heating pipeline leakage detection.
Study on Positive and Negative Materials of High Performance Ion Batteries
Authors: Song Jialong , Sun Zijia , Sun Mingfen
Published: March 2020

Study on positive and negative materials of high performance Ion batteries is presented in this manuscript. In recent years, sodium ion batteries have developed rapidly, and a number of key materials with electrochemical activity have emerged. Among them, the transition metal oxide as a core sodium ion battery positive electrode shows considerable sodium-embedded capacity, but the capacity decays severely during continuous cycling. This paper studies the novel findings on the mentioned issues to provide the new perspectives for assisting the future research.
Experiments Research on Electrical Discharge Grinding Polycrystalline Diamond Tool based on Surface Quality Analysis
Authors: Jia Yunhai , Guo Jianmei , Zhang Qinjian , Sun Yue
Published: March 2020

As the hardest material in the field of synthetic materials, polycrystalline diamond has attracted more and more attention in the field of tools, which reflects the basic characteristics of ‘high efficiency, precision and flexibility’ of modern advanced cutting technology and clean production. Electrical discharge grinding (EDG) is often used in polycrystalline diamond tools, especially in special shape, thin and fine edge cutting tools. Taking two kinds of grain size of polycrystalline diamond as the research object, taking the machining test and material test as the analysis means, this paper simply compares the surface quality of disc electrode and wire electrode machining, and studies the influence of diamond particle size, electrode polarity and electrode rotation speed on the surface quality and material removal rate of precision electrical discharge grinding polycrystalline diamond. The results show that there is no porous structure, good surface quality and no selectivity in discharge removal when using the negative polarity machining. With the increase of electrode rotation speed, the removal amount of polycrystalline diamond material increases gradually, and the surface roughness of polycrystalline diamond material decreases first, then increases. When the electrode rotation speed reaches 80 m/min, the surface roughness of the polycrystalline diamond sample reaches the minimum value, and the removal amount of polycrystalline diamond material also tends to be stable.
Study of a fatigue damage model for flange considering the friction coefficient of the faying face
Authors: Zhao Yuhao , Wei Jing , Yin Wencan , Zhang Shijie
Published: March 2020

In the flange connections, part of the load is transmitted by the friction moment between the faying faces, thus the distribution of the input load in the connection is changing with the friction coefficient. Current models usually calculate the fatigue damage directly according to the load spectrum without considering the variation of the load due to friction coefficient. In the paper, a fatigue damage model for flange plate considering friction coefficient is proposed, and the influence of friction coefficient on the load distribution of the connection is deduced. Based on Palmgren-Miner linear damage theory, the algorithmic expressions of fatigue damage at varying friction coefficient are derived, which not only assesses the fatigue strength of flange under variable friction coefficient, but obtains the friction coefficient range which meets the fatigue strength requirement of flange connections.
Study on the Preparation Technology of Hollow Yarn with Hollow Stability
Authors: Li yifei
Published: March 2020

At present, there are few researches on hollow yarn. This paper mainly focuses on the strength of hollow yarn. The purpose is to prepare a hollow stable hollow yarn. Several different spinning processes were used in the experiment. Control group and experimental group were used in the experiment. Among them, the control group was prepared by spinning ordinary hollow yarn; the experimental group was prepared by soluble vinylon and hot-melt polyester filament. According to the difference of melting point and solubility in water of these materials, two groups of hollow yarns are formed by high temperature heating and water bath heating respectively. After spinning, the stability of hollow yarn was tested by strength test.
Comparative Study on Molecular Dynamics Simulation Methods of Mechanical Properties of Tricalcium Silicate and Dicalcium Silicate
Authors: Bu Yuhuan , Du Wenxiang
Published: March 2020

A comparative study on the mechanical properties of tricalcium silicate (C3S) and dicalcium silicate (C2S) under different force fields and different sizes by molecular dynamics method. The C3S and C2S single crystal and supercell molecular model were established respectively. The molecular dynamics simulation was carried out under the three force fields of COMPASS, COMPASS II and Universal to obtain the mechanical properties of the nanostructure. It is found that the COMPASS II force field is suitable for C3S and C2S mechanical simulation performance under the same size, which is closer to the literature value. Under the same force field, the large-size unit cell mechanical performance simulation is more stable and reliable than the small-size simulation result. Mechanical properties are one of the most important properties of cement stone. The hydration products of C3S and C2S are responsible for the mechanical strength of the cement stone. Therefore, studying the mechanical properties of C3S and C2S is of great significance for the development of cement materials.
Polystyrene-supported nickel complex catalysed deprotection of allylic tertiary amine with sodium borohydride
Authors: Bao Lingxiang , Liang Honggang , Zhang Haonan , Yan Zhiyuan , Sun Chenghui , Pang Siping
Published: March 2020

This work represents a green and facile approach for the polystyrene supported nickel catalysed deprotection of allylic tertiary amine. The careful instrumental investigations with XPS, TEM, TGA, XRD and ICP-AES precisely characterized the developed heterogeneous catalyst. Cheap metal, mild reaction conditions, good yields as well as the reusability of the catalyst made this method more environmentally friendly.
Failure analysis of the low-pressure blade lacing wire in steam turbine
Authors: Qiao Lijie , Feng Keyun
Published: March 2020

The failure analysis of the low-pressure last stage blade lacing wire in steam turbine made of 0Cr17Ni4Cu4Nb(S17400) is presented. The failure of the low-pressure last stage blade occurred at 7 operating years. Several examinations were carried out to identify the blade lacing wire failure’s root cause: macroscopic inspection, chemical composition analysis, hardness test, metallographic analysis, microscopic examination and inspection of maintenance records. It is found that there is local displacement of the roots of the low-pressure rotor, and the collision between the lacing and the lacing holes is the direct cause and external mechanical incentive of the lacing fracture.the high content of P element and the high hardness reduce the plasticity and toughness of the material which is the intrinsic factor of this tensile fracture, without obvious plastic deformation, the low-pressure last stage blade lacing wire breaks rapidly. It is suggested to find out the local displacement of blade root and fix it in a reliable way, check the strength after eliminating the harmful defects such as cracks, and replace the blade if necessary, strictly according to DL/T438-2016 and the manufacturer’s standard requirements for the inspection of the lacing wire before use.
Damage identification of bridge structures based on curvature mod
Authors: Sun Zongjun , Li Kai
Published: March 2020

Based on the modal analysis theory of bridge dynamic characteristics, a pre-damaged reinforced concrete model beam is established by ANSYS as the object of analysis. The regularity of modal parameters such as displac, ement mode and curvature mode of the model beam at the preset damage location and different damage degree and the identification of modal parameters in structure damage are studied by finite element numerical analysis. Sensitivity. The results show that the displacement mode is difficult to identify the damage of the structure effectively, but the curvature mode can reflect the damage of the structure more accurately. The damage identification method based on the curvature mode can be applied to the damage diagnosis of the structure in practical engineering.
Effect of Lignin Removal on Moisture Absorption of Wood
Authors: Zhang He , Chen Yuchen , Wang Yongkuo
Published: March 2020

In the study, we carried out heartwood and sapwood of fast-growing Chinese fir as research objects, the lignin was removed by sodium chlorite method, then the changes of wood chemical composition were detected by Raman spectra, the moisture absorption changes of wood were studied by saturated salt solution method, and the H-H model fitting data was used to analyze the effect of lignin removal. It aims to provide reference for the research and development of new wood modification technologies or wood-based products [4]. The results showed that there was no significant difference between sapwood and heartwood when the relative humidity was lower than 30%. With the increase of relative humidity in the environment, the water absorption capacity of sapwood cells was higher than that of heartwood. The water absorption capacity of heartwood and heartwood after delignification was significantly stronger than that of control wood, especially when the relative humidity was 95%, the equilibrium water content reached about 60%.
Effect of Post-weld Heat Treatment on Microstructure and Mechanical Properties of Al-Zn-Mg-Cu Alloy Welded Joint
Authors: Zhang Xiang , Xie Dejie , Chen Bo
Published: March 2020

Metal inert-gas welding (MIG) test was carried out using ER5183 welding wire as filler metal and Al-4.8Zn-1.6Mg-0.16Cu alloy profile as base material. Different post-weld heat treatment processes were adopted for Al-4.8Zn-1.6Mg-0.16Cu alloy welded joints. The effects of different post-weld heat treatment processes on the microstructures and mechanical properties of welded joints were studied by means of hardness test, microstructure observation and scanning electron microscopy analysis. The results show that the mechanical properties of welded joints can be improved by artificial aging treatment after welding. At the same time, the comprehensive mechanical properties of re-solution and aging after welding will be significantly improved. The inhomogeneity of welded joints and the distribution of strengthening phases will also be improved, the softening of heat affected zone will almost disappear, and the strength of welded joints will be restored.
Numerical Calculation of Composite Water Lubricated Bearing Considering Effect of Elastic Deformation
Authors: Liu Changjiang , Yao Bin , Gao Genyuan , Wang Yanzhen , Mao Yang
Published: March 2020

Traditional bearing design neglects the influence of elastic deformation of materials on bearing lubrication characteristics, based on a new type of polymer composite water-lubricated bearing materials, the influence of elastic deformation of bearing material is introduced into the simulation. The lubrication performance of the water-lubricated bearings is studied with respect to material parameters and structural parameters. The effects of the elastic deformation on the lubrication characteristics such as the maximum pressure value and the minimum film thickness were compared and analyzed under different bearing clearance structures of a certain type of stern bearings. The results show that, the maximum water film pressure of bearing increases with the clearance ratio, and the maximum water film pressure of elastic bearing is less than that of rigid bearing. With the increase of clearance ratio, the elastic deformation of bearing increases linearly. The increase of bearing elastic deformation results in the difference between minimum water film thickness and maximum water pressure between the elastic bearing and rigid bearing.
Optimization of the internal damping rubber elements of the small diameter roller wheel of tracked system
Authors: Korostelev S. A. , Verbilov A. F.
Published: March 2020

The article presents the formulation and solution of the problem of optimization of the internal damping rubber elements of the small diameter roller wheel of tracked system. The search for the optimal design is based on the results of calculating the stress-strain state of the rubber element caused by the assembly of the roller and loads during subsequent operation. As an objective function, the specific energy of deformation of the rubber was chosen. The geometric parameters of the rubber element of the roller wheel in the initial state and after installation in the structure are taken as variable parameters. Explicit and functional constraints in the form of inequations are imposed on the variable parameters. The results of solving the optimal design problem are presented.
Influence of friction forces in limiter-eyelet contact on twisting angles of the rubber elements of tracked system hinges
Authors: Korostelev S A , Gorbachev A V , Verbilov A F , Kovalev V V
Published: March 2020

The article presents a study of the influence of the radial deformation limiters of rubber-metal compounds of tracked systems on the loading of rubber elements. Description of the mathematical model of the dynamic behaviour of a tracked propulsion unit with rubber-metal hinges is presented. Dynamic calculations using the software package based on the equations were performed. The analysis of the results of the computer calculation revealed the influence of friction forces and moments in the contact zone of the limiter-eyelet.
Indicators of the efficiency for using of road-building machines at various levels of management decisions
Authors: Dotsenko A I , Mandrovskiy K P
Published: March 2020

Methods of technical and economic evaluation of road-construction machines are highly developed but their operation requires a wide list of initial data which is very difficult to obtain without monitoring systems. In modern conditions, economic factors determine the possibility of machines’ operation and the technical excellence of the machine is viewed by considering the cost of ownership and operation. This determines the relevance of the application of technical and economic assessments. In order to ensure the feasibility of applying of such technical and economic indicators towards the performance evaluation, they need to be adapted for use in monitoring systems. Modern monitoring systems allow you to monitor the technical and operational characteristics without a comparison with the indicators of the economic sphere. There is almost complete uncertainty in the methods of selection and evaluation of equipment that could be used in practice in modern conditions characterized by the presence in the market of equipment of the same purpose from different manufacturers. In such conditions, a system for collecting and processing the information with feedback would be convenient - a monitoring system for effectiveness evaluation. Feedback is necessary for creatingthe control actions in order to increase the efficiency or maintain it at satisfactory level - performance management. The development of methods of both technical and economic assessment which are suitable for using for road-construction machines and adapted for implementation in monitoring systems is a relevant topic of scientific research.
Structural analysis of Braking Energy-Conservative Systems of Transport Technological System
Authors: Isakov V S , Erejskiy A V , Kvetkin A A
Published: March 2020

The possibilities of application of the ways and means allowing beneficial use of kinetic energy of moving masses of various transport and transport-technological machines in the course of braking are considered. The concepts of development of inertial and energy-storage braking means for different types of actuating units are presented. The generalized block schematic diagram of a multimass object with the inertial energy-storage braking system and morphological matrix of possible technical solutions are offered. Various offers on realization of inertial and energy-storage braking systems in the designs of technological machines are shown and the results of the researches of energy-storage braking are presented.
Improving the efficiency of existing methods of diagnosing the hydraulic drive of road-building machines
Authors: Piramatov U A , Pugin K G
Published: March 2020

The article presents modern methods of diagnosing hydraulic drive. The drawbacks of modern diagnostic methods are revealed. The negative consequences of the effect of stagnation of the working fluid. The results of studies of working fluid samples are given. Suggested ways to solve the existing problem. A method for determining the nodes subject to the effect of stagnation of the working fluid is proposed. The effect of solving the problem of stagnation of the working fluid is determined.
SN-EVM unit for experimental studies of stability in circular cylindrical shells under combined loading
Authors: Cheremnykh S V , Skudalov P O
Published: March 2020

The article summarizes results of experimental studies of stability in circular cylindrical shells under combined loading by compressive force, internal pressure and torsion at the SN-EVM unit, developed by the Department for Strength of Materials, Theory of Elasticity and Plasticity at Tver State Technical University. It gives description of the test facility and methodology of experiments for studying the elastoplastic properties of materials under combined loading. It cites the processed experimental results for comparison with the formulated theory of bifurcation for the thin-walled circular cylindrical shell.
Formation of the network of spare elements warehouses
Authors: Kim B G , Nasrulloeva R A , Shakir Z N , Zakrevskaja L V
Published: March 2020

Discusses the redundant machinery construction enterprises. The method of calculation of a network of warehouses taking into account the possibility of different conditions of the reserve from the part to the backup machine. The technique allows you to determine the required number of warehouses of different levels, taking into account the time of delivery of the spare element from the warehouse on the other hand, it is necessary to take into account that the increase in inventory helps to slow down the turnover of reserve elements, increases the cost of the Insurance Fund.
Modern pedagogical education requirements for students at construction and mechanical engineering faculties
Authors: Skudalov P O , Cheremnykh S V
Published: March 2020

The professional activity of a fundamentalist teacher with classical education fully involved in the general educational and scientific process, and a teacher who successfully combines his professional activity with industrial one is considering. Professional characteristics of a teacher with a higher education and acquirements obtained at an industrial enterprise are compared to attainments of a teacher with fundamental pedagogical education to monitoring and eliminating gaps in students’ knowledge.