bluuebunny/crossref_metadata_2025 huggingface dataset:
Charge Transport Properties of Cu2S/Bivo4 Composite Photocatalyst
Authors: Wang Lijie , Yu Ping , Wang Xingyue , Cui Xianghong , Liu Xiaodong , Sui Xin , Zhang Xiaochen , He Dongqing
Published: April 2020

The Cu2S/BiVO4 composite photocatalysts had been synthesised by a simple solution adsorption method. The obtained samples were characterised by means of field emission scanning electron microscope (SEM), X-ray diffraction patterns (XRD), UV-visible absorption spectrum techniques and transient photovoltage spectra (TPV). The results showed that the Cu2S nanoparticles were evenly loaded on the surface of the dumbbell-like BiVO4 composites. Compared with pure BiVO4, Cu2S/BiVO4 composites had better photocatalytic activity. Furthermore, the photogenerated charge transport properties of Cu2S/BiVO4 composites were investigated by means of TPV technique. The interface between BiVO4 and Cu2S enhanced the separation efficiency of photogenerated charge carriers, thus, the photocatalytic activitie of Cu2S/BiVO4 composites was enhanced.
Analysis of Improving Impact Resistance and Heat Treatment Method of Tempered Glass
Authors: Bai Bin , Liu Zengtao , Zhang Baofang , Zhou Guowei
Published: April 2020

At present, glass is common in our lives. Glass has excellent physical and chemical properties. It has high compressible strength, high hardness, transparency, good stability, and is not easily deformed. It is an inorganic non-metallic material with a wide range of uses. With the development of science and technology, the scope of application of glass is more and more extensive, and the strength requirements for glass are also getting higher and higher. How to improve the impact resistance of tempered glass, this article studies the heat treatment processing technology and parameter adjustment, and the appropriate process route through appropriate heat treatment methods, so as to improve the impact resistance of tempered glass. Inspection has verified the rationality of the process.
Preparation and Optical Properties of ALF3: Cr3+ Phosphor
Authors: Cai Min , Yao Xinyan , Man Shiqing
Published: April 2020

Cr3+ doped AlF3 phosphors were synthesized via a facile solid state reaction method. XRD results showed that the prepared samples are single-phase. In the emission spectrum of AlF3:Cr3+ powders, there is one sharp line emission located at 695 nm, which is arisen from 2E→4A2 transition of Cr3+ in AlF3 lattice. The excitation spectrum of AlF3:Cr3+ powders monitored at 695 nm emission have two excitation bands of 500~600 nm and 380~450 nm. At room temperature, the fluorescence decay of Cr3+ ions in AlF3 have been measured and the fluorescence decay curve have been reported.
Preparation and Properties of Cr3+ Doped Mg0.388Al2.408O4 Red Phosphor
Authors: Yao Xinyan , Cai Min , Man Shiqing
Published: April 2020

The Cr3+ activated Mg0.388Al2.408O4 phosphor was synthesized by sol-gel and high temperature solid phase method in the air at 1400°C for 6h. The phosphors structure was measured by X-ray diffraction (XRD); excitation spectra, emission spectra and decay lifetime were obtained by fluorescence spectrophotometer equipped. It showed that the sample has two strong broad absorption ranging from 390nm to 420nm and 530nm to 590nm, and the peak positions are around 407nm and 552nm; the maximum of the red emission which is due to the transition from the 2Eg(2G) excited state to the 4A2g ground state is at 688 nm. And the lifetime of Cr3+ in the Mg0.388Al2.408O4 host is 4.8255ms.
The effect of the amount and type of curing agent on the basic properties of UF resin
Authors: Li Jing , Chen Yuzhu , Jing Mingwei , Feng Qiaolin , Yang Yupeng , Li Wei , Yi Maoyu , Ou Chuan , Fu Chengang
Published: April 2020

In this study, the effects of four single-component curing agents on the basic properties of UF resins were investigated. The basic properties include pH, gel time and valid period. The studies have shown that different curing agent types and additions have different effects on the basic properties of urea-formaldehyde resins. The degree of influence of different curing agents of the same addition amounts: APS>AC>AS>AP, the degree of influence of different addition amounts of the same curing agent: 5%>2%>1%. Comprehensive comparison of four single-component curing agents, the optimal curing agent is AC, the optimal addition amount is 2%. This study laid the foundation for the subsequent study of the effects of multi-component curing agents on the properties of resins.
Research on the Improvement of Spacecraft Manufacturing Enterprise Quality Management System Audit Based on Process Method
Authors: Liu Wei , Sun Gang , Zhu Kaimin , Zhang Bin
Published: April 2020

This article combines the spacecraft manufacturing enterprises that simultaneously build and operate ISO9001 and AS9100 quality management system. According to the process strengthening requirements of quality management system standards, research and improve the audit work with process method as the core. This article introduces the "turtle chart" process method audit management tool, summarizes the specific model and implementation points of the process method in the quality management system audit. This article analyzes the important role of this method in the internal audit of quality management system, in order to provide reference for spacecraft manufacturing enterprises to improve the audit of quality management system.
Application of Green Manufacturing Process in Cutting
Authors: Jiao Runyu , Chen Bo
Published: April 2020

Reducing the consumption of resources by traditional manufacturing industries and avoiding environmental pollution caused by traditional manufacturing industries is one of the major problems facing the manufacturing industry in the new century.Nowadays, countries adopt a sustainable development strategy, which is about the manufacturing cycle of products around green manufacturing.Green manufacturing is the only way for sustainable social development. It plays an important role in equipment manufacturing, national defense security and the national economy.In this paper, the use of traditional and green processing technology in the key machining process is analyzed, and the evaluation method of quantitative measurement of green manufacturing process elements is deeply studied.Through the analysis, optimization and evaluation of raw material loss, auxiliary materials and energy consumption, pollutant discharge and other factors in the engine machining process planning, this paper has achieved the greening of mechanical processing and mechanical processing of other parts. Have a certain guiding significance.
Monitoring Deep Mining Similarity Material Model of Super-Thick and Weak Cementation Overburden by Digital Photography
Authors: Zhang Guojian , Lv Yi’nan , Guo Guangli , Yu Chengxin
Published: April 2020

In this paper, the similarity material model is conducted to investigate the movement law and failure pattern of the super-thick weak cementation overburden. In addition, the photographing scale transformation-time baseline parallax (PST-TBP) method and the Xi’an Jiaotong University Digital Close-range Industrial Photogrammetry System (XJTUDP) software were used to monitor similarity material model. The findings can be summarized as follows: (1) To some extent the PST-TBP method can make up for the deficiency of the XJTUDP software because its measurement accuracy is about 0.5mm; (2) The first breaking span of the immediate roof reached 240m, and the cyclic fracturing length was about 60m. It still shows the characteristics of the inadequate mining when the surface reaches fully mining. It needs more mining space to reach fully mining; (3) The (PST-TBP) method and the XJTUDP measurement system provide technical support to study the dynamic development process of regional deformation caused by deep mining.
Study On the Melting And Corrosion Resistance of Fe-Cr-Si Dual Phase Alloy
Authors: Hu Lixiang , Hu Binsheng , Gui Yongliang
Published: April 2020

In this paper, Fe-Cr-Si multiphase alloy with both ductile and brittle phases was prepared by vacuum arc furnace with high purity powder mixture of Fe, Cr and Si as raw materials. The microstructure and properties of the alloy were studied by OM, SEM, and XRD. The experimental results show that Fe-Cr-Si alloy can be made into two-phase alloy, which mainly consists of ductile phase and Fe22Cr7Si10 brittle phase. It is found that the matrix has a higher iron content, lower hardness and higher chromium content in brittle phase. The silicon element is evenly distributed in the sample. The corrosion resistance of the alloy is very strong compared with 06cr19ni10 steel.
Study on the Morphology of the Streamer with Carbon Nanotube Electrode in Atmospheric Environment
Authors: Liu Xin
Published: April 2020

The low temperature streamer at atmospheric pressure has good characteristics of pollutant removal, and the characteristics of the streamer are closely related to the discharge conditions, and the structure and material of the electrode also affect the characteristics of the streamer. In our work, the argon gas was discharged under different conditions and the morphology of streamer was shoot by a high-speed camera, then the morphology of the streamer that generated by the carbon nanotube electrode was compared under the same conditions. The experimental results show that when the electrode is electroplated with carbon nanotubes, the light intensity and the diameter of the streamer will increase, and the morphology of the streamer that in the atmosphere will change regularly with the discharge conditions. The experiment proved that the morphology of the streamer will be influenced by the discharge conditions because of the electric and flow fields, and the carbon nanotube electrode will generate more intense streamer.
Fundamental Research on Electronic Image Recognition of Cylindrical Zno Nanorods Based on Deep Learning
Authors: Liang Yuzhou
Published: April 2020

ZnO is recognized as one of the most important photonic materials in the blue-violet region due to its straight-width band gap and large excitation bonding energy. Since ZnO nanorod array performs superior optical and field emission properties, a lot of efforts have been made in the fabrication of a vertically ordered ZnO nanorod array. The shape and size of ZnO nanorods have a significant effect on PEC property. In order to efficiently recognize and measure the shape and size of ZnO nanorods, a new method based on deep learning model mask r-cnn is proposed to detect cylindrical ZnO nanorods. The SEM images of ZnO nanorods were used as a data set for training. Adjust the size of the bounding boxes that model generated to make it more suitable for the data set. At the same time, improve the NMS (non-maximum suppression) algorithm to reduce the missing detection rate, and achieve a good detection effect on the SEM images of ZnO nanorods.
Zno SEM Image Segmentation Based on Deep Learning
Authors: Li Linmao
Published: April 2020

The radius of nanomaterials, which will affect the specific surface area of the nanowires and other functions, is important for the optoelectronic application of nanomaterials. The Scanning Electron Microscopy (SEM) is an effective method to observe the spatial morphology of nanowires. However, the current measurement of topographical features mainly uses manual methods, which will bring about instability errors, especially when measuring a large number of them. Deep learning provides an efficient, fast way to identify and segment nanowire SEM images. Through deep learning methods, the spatial characteristics of nanomaterials can be measured quickly, which aim to explain the relationship between features and radio and television applications from a statistical point of view. In this paper, we design a deep learning image recognition system to measure the radius.
Thermal Behavior and Molten Pool Morphology during Laser 3D Printing Process of Alloy Steel Powder
Authors: Zhao Minghuang , Duan Chenghong , Luo Xiangpeng
Published: April 2020

In this paper, a finite element analysis (FEA) model is proposed to systematically study the thermal behavior of metal material in Selective Laser Melting (SLM) 3D printing process. It is found that the material undergoes a fast and complex thermal cycle process. Laser beam can re-heat the adjacent formed scanning track and layer, and also produce a certain preheating effect on the unformed powder bed of the adjacent scanning track when laser beam scans a track, which is conductive to improve metallurgical bonding performance of SLM-fabricated parts. With the increase of scanning tracks or scanning layers, the peak temperature and molten pool lifetime increase owing to the thermal accumulation effect, but the increasing trend gradually slows down. The peak temperature and lifetime of each scanning track center in the second layer are larger than those of the corresponding scanning tracks in the first layer, respectively. Furthermore, SLM experiments are carried out to study complicated molten pool morphology in SLM process. The results obtained in this study have certain guiding significance for understanding thermal mechanisms of SLM process.
Microstructure and Magnetic Properties of Textured Barium W-Type Hexaferrite with Rare-Earth La3+ Substitution
Authors: Liu Qian , Wu Chongsheng , Wang Yu , Liu Yingli , Zhang Huaiwu
Published: April 2020

Textured M-type barium hexaferrites (BaM) in form of BaLaxNi2Fe16-xO27 (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) were synthesized using a ceramic process. The effect of La3+ substitution on the microstructure and magnetic properties of the resulting BaW samples was investigated. Pure BaW phase formation for all samples was confirmed by the X-ray diffraction patterns. The scanning electron microscopy images revealed that the grains in the textured BaW had realigned along the hexagonal crystallographic c-axis, which was in good agreement with the results of magnetic hysteresis loops. Moreover, textured BaW with a high squareness ratio (Mr/Ms= 0.80) was obtained. Due to the La3+ substitution, the magnetocrystalline anisotropy field (HA) decreased dramatically while maintaining the c-axis anisotropy. The textured BaW are potential candidates for the design of self-biased microwave devices such as circulators and isolators operated at Ku or X band.
Synthesis of Two Kinds of Mesoporous Diatomite by Microwave Assisted Sol-Gel Method and Its Adsorption of Ammonia Nitrogen in Wastewater
Authors: Wang Guohe , Xu Yuanyuan , Wang Chenyi , Gao Yuchao , Li Linlin
Published: April 2020

The microwave-assisted sol-gel method was used to synthesize mesoporous diatoms (DM) and magnetic mesoporous diatoms (MDM), and used as adsorbent to remove ammonia nitrogen from water. The effect of reaction time, solution pH, and initial concentration of ammonia nitrogen on adsorption was studied, and the adsorption Kinetics and thermodynamic characteristics of DM and MDM were analyzed. The results showed that at 25 °C, when the dosage of DM and MDM was 4 g/L, the initial concentration of ammonia nitrogen in the solution was 50 mg/L, the value of pH was 7, and the adsorption time was 30 min, the adsorption of ammonia nitrogen in solution by DM and MDM was 6.95 and 7.79 mg/g, respectively. DM and MDM had good adsorption effect on ammonia nitrogen, and the adsorption process complied with the Pseudo-second-order kinetics equation and Freundlich isothermal adsorption model.
Multi-Cation Blue Perovskites Light-Emitting Diodes with Enhanced Luminescence
Authors: Wu Yongwei , Yang Guang , Jiang Pei , He Bo , Duan Miao , Yin Yongming , Li Dongze , Chen Shujhih , Zhou Hang , Lee Chia-yu , Zhang Shengdong
Published: April 2020

2D perovskites, typically with a standard formula of L2An-1MnX3n+1, have recently attracted significant attention due to their promising optoelectronic properties. Normally, they contain a mono cation (e.g., butylammonium (BA+) or phenylethylammonium (PEA+) for “L” and methylammonium (MA+) or formamidinium (FA+) for “A”). In this work, multiple cation-substitution strategy was used to improve the luminescence and emission efficiency of perovskite thin films. As a result, brightly blue emission with a high photoluminescence quantum yield of 26% was achieved. Finally, the according perovskite light-emitting diodes reached a brightness of 110 cd/m2, and a maximum external quantum efficiency of 0.79%.
Design and Construction of Protective Coating for Qiongle Concrete Expressway Bridges in Hainan Province
Authors: Zhao Qiuhua , Guo Tao , Lu Xiaoxia
Published: April 2020

Through analysing the characteristics of the corrosion environment where Qiongle concrete expressway bridges work, and its influence on the durability of the concrete structure, this paper made a comparison among common coating systems, and put forward a reasonable coating design scheme as well as the corresponding technical requirements. Focused on the problems encountered in the trial tests, solutions were proposed to ensure the coating quality, which enabled it to play a long-term and effective role in protecting the concrete structure under corrosive environment, avoiding or procrastinating the occurrence of durability disease, and ultimately improving the safety and durability of the concrete structure.
Lean-Production Development in Shoemaking Industry: A Case Study
Authors: Li Jing , Ding Kaifang , Zhu Yongming
Published: April 2020

It was generally found in most SMEs of China that there are many difficulties in on time delivery. Based on the study of bottlenecks theory and other relevant theories, we proposes an improvement model. First is the identification of the bottlenecks by pinpointing the relationship between customer demand and the actual capacity of the enterprise. Then is the analyzation of the factors that restrict the bottleneck productivity and the construction of the corresponding ISM, and the improvement tools of IE is used to break through the bottlenecks. Once the bottlenecks drift out of the production chain, the use of VSM finally eliminates waste within the enterprise. Taking H as a case study, the value-added rate of the value stream increased by 5.84% through the application of the above improvement model.
Study on the Preparation of Modified Polypropylene Fiber Reinforced Cement-Based Composite
Authors: Ma Jun , Sun Yuanbao , Jiang Xufeng , Li Leibo
Published: April 2020

The concentrated HNO3 is applied to carry out the surface modification of polypropylene fibers for the preparation of PP fiber reinforced concrete composite. The modification effect of the oxidation reaction is evaluated by the mechanical testing of the PP fiber reinforced concrete composite. The stretching vibration of O-H and C=O bond centered at the wave number of 3300 cm−1 and 1720 cm−1, respectively, indicates the oxygen-containing groups are generates on the surface of the modified polypropylene fiber. The contact angles of the modified polypropylene fiber are also significantly reduced to about 81°, compared with the untreated polypropylene fiber (112°). SEM analysis suggests that the corrosion effect of HNO3 modified polypropylene fiber on the surface is quite obvious since the surface becomes very rough and has grown pore structure near the surface area. Finally, the modification PP fiber reinforced cement composite has an increment of 11.5% on the fracture strength properties compared by the untreated PP fiber. The results indicated that the oxidation process by the concentrated HNO3 could substantially improve the mechanical properties of modified PP fiber in the concrete composite. The reason should be the elevated hydrophilic properties of the modified PP fiber improve the interface bonding strength which is crucial for the performance of the composite.
Structure Design and Research on a New Tire Emergency Inflation System
Authors: Rui Jingmin , Xu Yang , Zhu Qingsong , Liu Lihong , Yao Jia
Published: April 2020

Tire burst is huge harmful, a new tire emergency inflation system was put forward based on the airbag technology to reduce the harm of tire burst in this paper. Firstly, the pyrotechnic gas generator and its matching wheel hub were designed, the tire emergency inflation system model was established and the inflation process was simulated. The results show that the numerical model of tire emergency inflation system can well simulate the inflation process after tire burst. The peak time of gas production has little effect on the peak pressure of gas in the airbag after inflation. The peak time of gas production is different, but the final pressures in the airbag are all about 250 kPa, meeting the performance requirements. Therefore, the function of tire emergency inflation system designed can be realized.
Track Design of Track-Wheel Transport Vehicle and Strength Analysis of Important Components
Authors: Yang Yuchuan , Cai Tong , Xu Xiaojun
Published: April 2020

Through the comparative analysis of different types of transport vehicles, the paper puts forward the concept of Track-Wheel transport vehicles and expounds the crawler travel mechanism of the wheel-shift interchange transport vehicles. It is concluded that the Track-Wheel transport vehicle has the advantage of operating in harsh environments such as mud and sand. The article designs the track mechanism and focuses on the strength checks of the important components of the track walking mechanism, namely the track, the load wheel and the load wheel axle. And it is concluded that under the maximum load, the track, the load wheel and the load wheel axle can meet the bearing requirements.
Research on the Rupture of Certain CNG-II Gas Cylinders during the Leak-Before-Break Test
Authors: Xiong Shutao , Huang Song , Li Bin , Zhao Zhongguo
Published: April 2020

We are studying the Leak-before-break (LBB) test, which is an important test for the safety performance verification of CNG-II bottles, and it is a necessary link for new product identification. We ruptured during the LBB test of a CNG-II gas cylinder. Through the chemical composition analysis, metallographic observation, mechanical performance test, scanning electron microscope and other tests of the failed gas cylinder, we found that the cylinder failure was due to the curved part. There are oxide slag inclusions. Under the fatigue test under the action of alternating load, slag inclusions are used as the fatigue source, which accelerates the crack growth and eventually causes the cylinder to fail.
Simulation and Analysis of a Kind of Gas-Liquid Linkage System Based on Response Surface Method
Authors: Bao Zhongfu , Zeng Dejiang
Published: April 2020

The simulation analysis is carried out for a kind of gas-liquid linkage system composed of gas-liquid conversion cylinder. Firstly, the dynamic characteristics of hydraulic system, pneumatic system and pneumatic hydraulic system are compared. Then through batch analysis, the influence of the design parameters of the gas-liquid converter on the system is analyzed. Finally, by using the method of experimental design, the influence of the main parameters of the gas-liquid combined system on its dynamic characteristics is clarified, which provides the basis for the subsequent design and development.
The Design of Gantry Welding Production Line System Based on PLC
Authors: Yuan Junfeng , Tian Chenghua , Li Hui , Wang Haitao , Zhou Chunlin
Published: April 2020

This paper introduces the composition of the mast welding production line, and designs the process flow of the production line. With Siemens S7-300 PLC and ET200SP as the core, this paper designs a production line control system is designed. In addition, this paper expounds on the hardware design and software design of the PLC system in detail and describes the communication methods between the PLC and the robot, and programming is conducted based on modular programming, thus making the system become stable and scalable.
Fatigue life prediction method of mechanical parts based on Weibull distribution
Authors: Wang Yang , Peng Zhiling
Published: April 2020

Aiming at the randomness of fatigue life of mechanical parts, the reliability analysis and fatigue life prediction of mechanical parts are carried out through the Weibull distribution of three parameters. The process of solving the complex transcendental equation is analyzed, and the method of solving the likelihood function by unconstrained optimization method is proposed to estimate the values of the three parameters of Weibull distribution. A complete and accurate Weibull distribution model was established to analyze and calculate the data of gear tooth fracture, and the accuracy of the model was verified. The fatigue life of mechanical parts could be predicted by this model.
Application of CFRP Reinforcement Technology in Culvert Pipe
Authors: Li Dan , Li Yuebo
Published: April 2020

This paper put forward analysis and design for a worn drain pipe reinforced by CFRP. In engineering practice, it can solve the absent problems.
Study on Mechanism of Heating Temperature Field of Aluminum Foil Seal
Authors: Xin Chuanqi , Sun Shibo , Liu Jinming
Published: April 2020

The theoretical basis for non-contact sealing detection is lacking for the sealing performance of aluminum foil sealing. First, simulation and analysis of heat transfer characteristics of aluminum foil seals in heating temperature field using ANSYS software. The temperature field image sealed by aluminum foil is a closed and uniform annular region with high temperature. In the temperature curve, the temperature is concentrated at 70~80 celsius. It has symmetry characteristics, and there are 2 high temperature peaks; the other 5 are unlooped or uneven thermal image aluminum foil seal failed. A comparative experiment was then carried out to collect infrared thermal images of different types of aluminum foil seals under electromagnetic induction heating. Experiments show that the surface temperature field distribution calculated by the three-dimensional finite element simulation is consistent with the experimental temperature-field distribution. According to the distribution characteristics of the thermal temperature field, it can be evaluated the state of the sealability of the aluminum foil seal, and it can provide theoretical support for further optimizing the automation degree of the non-contact sealability test.
Research on Key Technologies of the General Module Library of Aeronautical Composites Production Line
Authors: Li Hui , Zhang Chao , Cui Jing
Published: April 2020

System simulation technology has become more and more widely used in aviation manufacturing industry. A general module library for aeronautical composites production line was developed, according to the characteristics of the production line layout and production process, combined with practical engineering experience. Based on it, the simulation analyst can create models for different types of composite material production lines quickly and easily, and can do the layout simulation evaluation, bottleneck research and scheme quantitative comparison and so on. Moreover, a demonstration usage of the module library for a practical case was given.
Study on the Adsorption of Methyl Red by Bentonite / Chitosan Composites
Authors: Xiang Pengzhi , Deng Chao , Liu Longjiang , Huang Yao
Published: April 2020

A composite material is formed by using chitosan and bentonite under the condition of dissolution with acetic acid. The material was characterized by scanning electron microscope thermogravimetric analysis and infrared spectroscopy. The effects of initial concentration of methyl red, adsorption time, pH, and amount of adsorbent on adsorption were investigated. Then, the adsorption process was analyzed from kinetics, and related parameters were calculated. The results showed that the composite material has a wider pH range than using chitosan as an adsorbent to adsorb methyl red; The mass ratio of chitosan to bentonite is 0.08:1, the removal rate of methyl red is the best; The amount of adsorbent used is 0.7mg to reach saturation for a volume of 25mL of methyl red solution with a concentration of 20ug/l; the adsorption of methyl red by the material conforms to the pseudo-second-order kinetic model.
Research on Customers’ Purchasing Intention of Sports Shoes Based on Data Mining Application
Authors: Che Wanliu , He Gang , Gui Haixia , Shen Changxia , Yang Fan
Published: April 2020

The rapid development of e-commerce makes online shopping the main means of social consumption. How to extract useful information from massive semi-structured and unstructured customer data has become a hot issue in e-commerce industry research. This article uses the Octopus data crawler software to capture the online purchase information of Jingdong Mall sports shoes customers, and classify and analyze the information, and analyze the price, color, size, brand, etc. of the most popular sports shoes purchased by consumers; On the other hand, GeNie is used to generate online reviews of the Bayesian network structure model for the platform, and the cross-validation method is used to test the accuracy of the model. Finally, the key factors affecting the satisfaction of the sneaker customers are analyzed, and the customer satisfaction is studied. There is a significant causal relationship between the target variable and other related variables, and there are different degrees of correlation between different variables. The most important factor for consumers to purchase sports shoes is the comfort, quality and brand of sports shoes.
Experiment Analysis Research on Electrical Discharge Machining Polycrystalline Diamond Tool
Authors: Jia Yunhai , Guo Jianmei , Zhang Qinjian , Cai Yanhua
Published: April 2020

As the hardest material in the field of synthetic materials, polycrystalline diamond has been paid more and more attention in the field of tools, which embody the basic characteristics of "high efficiency, precision and flexibility" of modern advanced cutting technology and cleaner production. Electrical discharge machining is typically used in processing polycrystalline diamond tools, especially in the machining of special shape, thin and fine cutting tools. In this paper, 2 micrometer and 10 micrometer polycrystalline diamonds are taken as the research object, and the surface quality of the disc electrode and wire electrode is simply compared by means of process and material test. The effects of diamond particle size, electrode polarity and electrode speed on the surface quality and the material removal rate of precision electrical discharge machining polycrystalline diamond are studied. The results show that there is no porous structure and no selectivity in discharge etching when the negative polarity electrode machine is used. With the increase of electrode rotation speed, the removal amount of polycrystalline diamond increases gradually, while the surface roughness of polycrystalline diamond decreases first and then increases. When the electrode linear velocity reaches 80 m/min, the surface roughness of polycrystalline diamond sample reaches the minimum value, and the removal amount of polycrystalline diamond material tends to be stable.
Intelligent Heat Dissipation Device Based on Shape Memory Alloy
Authors: Wang Yanlong , Wang Sanwu , Huang Xi , Li Chengchi
Published: April 2020

With the miniaturization of electronic products, heat dissipation has gradually become a focus issue. Most current heat sinks use sensors to detect temperature. After reaching a certain threshold, the sensor generates a signal to drive the motor to drive the heat sink blades to rotate to achieve heat dissipation. This kind of heat dissipation method is more commonly used, but the sensor’s anti-interference ability is poor, and the heat dissipation device works at a higher temperature for a long time, the service life will gradually decrease, and the sensing and feedback structure is more complicated and prone to damage. In view of the shortcomings of the above existing products, this article uses the material characteristics of shape memory alloy springs to creatively design a green intelligent heat sink that combines memory alloy springs with sprocket drives. The device uses a memory alloy spring to sense the heat source, and makes full use of its mechanical characteristics to drive the blades of the radiator to rotate, ultimately achieving the purpose of heat dissipation. Experiments and simulation analysis on the operation of the device were conducted to further demonstrate its feasibility, and the benefit analysis and application prospects of the device were clarified through the benefit analysis.
Research on Positioning of Carrier-Based Aircraft Based on Particle Filter Optimized by Firefly Algorithm
Authors: Du Yajie , Zhao Jianjun , Wang Yi
Published: April 2020

In order to improve the positioning accuracy of the landing guidance radar, particle filter algorithm is used to estimate the positioning of the carrier aircraft. In order to solve the problem of the degradation of particle weight and the decrease of filter precision caused by the dilution of sampling particles in the conventional particle filter algorithm, an intelligent optimization particle filter algorithm based on firefly algorithm is proposed. By introducing the optimization mechanism of firefly algorithm into the conventional particle filter algorithm, particles can move to the high likelihood region, improve the overall quality of particle swarm, avoid particle degradation, and improve the filtering accuracy. The experimental results show that the algorithm is more effective and practical than the conventional particle filter algorithm.
Study of a Fast Over-Current Protection Based on Bus Voltage Drop for Gallium Nitride Power Device
Authors: Zhou Yang , Bai Zhijun , Gong Xiang
Published: April 2020

Due to the low threshold voltage, gallium nitride (GaN) high electron mobility transistor (HEMT) is prone to mis-conduction. Meanwhile, compared with silicon (Si) insulated gate bipolar transistors (IGBT) and silicon carbide (SiC) metal- oxide- semiconductor field effect transistor(MOSFET) devices, GaN HEMT have a shorter short-circuit withstand time at highvoltages, only a few hundred nanoseconds, which leads to a serious challenge to overcurrent protection. Traditional inductor detection and desaturation overcurrent detection have a long execution time, which are no longer suitable for over-current protection of GaN. Therefore, this paper proposes a new fast over-current protection method, which is based on the bus voltage drop. Through simulation and experimental verification, the result proves that the proposed protection method can detect the over-current signal within 100ns and turn off the GaN device within 400 ns, achieving fast and reliable over-current protection.
Study of a prefabricated structure perforated paving inlaid brick grid mat
Authors: Li Yulong , Yang Fan , Guo Huijie
Published: April 2020

In this paper, a prefabricated structure perforated paving inlaid brick grid mat is proposed, which is laid on the leveling layer and embedded in the brick block. The position of the brick is fixed by the positioning pile to ensure the gap between the bricks. Through the above manner, it is possible to directly use the bricks of common specifications to complete the permeable paving, simplify the paving operation, facilitate replacement and maintenance.
Study on the Influence of Oil Replacement on Furfural Content in Transformer Oil and Insulation Aging Assessment
Authors: Tang Xiaofeng , Su Zhengyuxi , Chen Peng , He Cui
Published: April 2020

The service life of a transformer was determined by the aging state of solid insulation. When the aging state of the transformer insulation reaches a certain level, oil replacement or oil filter was performed to improve the insulation ability of the insulating oil. A series of treatments of insulating oil inevitably result in the loss of furfural in the oil. In order to study the effect of oil replacement on the furfural content in oil, oil-paper insulation samples with different aging degrees were prepared under laboratory conditions. Besides, oil replacement was carried out in different aging stages, and the times of oil replacement was divided into once and multiple. Furthermore, the furfural content in oil was compared before and after oil replacement, and the effect of oil replacement on the furfural content in transformer oil was analyzed. The results showed that oil replacement had little effect on furfural content in the early aging stage, while it has a greater effect on furfural content in the late aging stage. In addition, the cumulatively of multiple oil replacement on the loss of furfural in oil can cause greater deviations in transformer aging evaluation. Therefore, the effect of oil replacement on the evaluation of insulation aging of transformer is not negligible.
The Role of Lightweight Design Method in Flexible Fixture Design
Authors: Jiao Chuanyan
Published: April 2020

To reduce the processing cycle and cost of sheet metal parts, a flexible fixture is designed by light weight method. First, the finite element analysis techniques adopted are summarized. Second, the static and modal analysis of the flexible fixture unit is carried out to obtain the design structure that meets the strength and rigidity requirements. Third, the lightweight design of the base of the positioning clamping unit is carried out after the analysis of the design structure of the positioning clamping unit. The modal analysis results of the positioning clamping unit show that at the operating frequency of 50Hz, the positioning clamping unit designed in this research would not resonate. Lightweight design results obtain the optimal section design parameters, achieve the purpose of reducing the weight of the flexible fixture base structure, and save the cost. Therefore, the results of this study provide a good idea for flexible fixture to adapt to the diversity of mechanical products.
The Influence of Material Hysteretic Property on Seismic Collapse-Resistant Capacity of RC Frame Structure
Authors: Huang Kai , Tan Zhenglei , Zhang Chao
Published: April 2020

To study the influence of hysteretic behavior of material on the seismic collapse-resistant capacity of reinforced concrete frame structure, a 5-story plane frame was selected as the research object, the incremental dynamic analysis method was used to analyze the collapse vulnerability of the structure. According to the collapse probability curve, the seismic collapse-resistant capacity of the RC frame structure with different hysteresis parameters was quantitatively evaluated. The research shows that the concrete strength grade has the most significant influence on the seismic collapse- resistant capacity. Reducing the concrete strength degradation or increasing the strain hardening rate of the steel can slightly improve the seismic collapse-resistant capacity ability; The concrete hysteresis pinch and the steel hysteresis energy consumption has no effect on the seismic collapse-resistant capacity of the structure. The seismic collapse-resistant capacity of the structure is negatively correlated with the strength grade of the steel bar, but its impact is not obvious.
Experimental Study on Dry and Wet Bending Behavior of CF/GF Inter Laminated Hybrid Composites
Authors: Chen Guotao , Mei Zhi Yuan , Fu Xiao
Published: April 2020

Experimental study on the bending characteristics of dry and wet state (100 °C boiled for 2 hours) in the same layering method, carbon (T700 unidirectional cloth)/glass (EWR800 multiaxial cloth) interlaminar hybrid composites with different mixing ratios. At the same time, the effects of 430LV vinyl resin and QC-350 epoxy resin on the bending properties of hybrid composites were compared and analyzed. The test results show that, In the same mixing ratio and the same test condition, QC-350 epoxy resin corresponding to the hybrid sample bending performance is better than 430LV vinyl resin; the wet bending strength and modulus of hybrid bending specimens are lower than those of dry bending specimens in varying degrees. The flexural strength and modulus of hybrid specimens increase with the increase of carbon fiber volume fraction. And as the volume of carbon fiber in the sample increases, the flexural strength and modulus of the hybrid sample increase to varying degrees. In addition, the results also show that the bending strength and modulus of hybrid bending specimens without post-curing treatment decrease in varying degrees at the same mixing ratio, whether in dry or wet state.
Fabrication and Properties of Polyimide/Aluminum Oxide Composite Films via Different Alkali Etching and Ion Exchange Technique
Authors: Zhang Mingyu , Liu Lizhu , Zhang Chunqi
Published: April 2020

The polyimide (PI)/aluminum oxide (Al2O3) composite films were prepared via alkali surface modification and ion exchange technique on flexible PI films. Firstly, the polyamide acid layers were formed on both surfaces of PI film through chemical surface modification in aqueous KOH and NaOH solution, respectively. Subsequently the ion exchange process was processed in AlCl3 aqueous solution. After final thermal annealing in air, the aluminum ions which exchanged on both surfaces of PI film became continuous Al2O3 composite layers. The surface morphology, microstructures, thermal and electrical properties of the PI/Al2O3 composite films were tested by the scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), electric breakdown voltage and corona-resistant measurement. Results from SEM measuring revealed that the surfaces of composite films became much rougher with the increasing alkali treatment time. FT-IR spectrums showed that the treatments of alkali surface modification and ion exchange had no effect on molecular structure of polyimide. TGA results showed that the excellent thermal properties of the film are maintained. Electric breakdown voltage of composite films showed monotonically decreased with the increasing alkali treatment time. Corona-resistant test results showed that the best corona-resistant times of composite films which using NaOH and KOH modification were up to 22.6 minutes and 15.4 minutes, respectively.
Study on the Heat and Pressure and Their Effect on the Surface Shape Precision of Optic in Continuous Polishing
Authors: Wang Yiren , Liao Defeng , Ren Lele , Zhang Feihu
Published: April 2020

In the process of ring polishing, the non-uniform temperature distribution in the element will make the shape of the element change greatly, which leads to the non-uniform pressure distribution between the element and the pad. According to Preston equation, uneven pressure distribution will produce uneven material removal rate and affect the surface morphology of optics. In this paper, the influence of temperature differenace on the deformation of the element is revealed, and then the relationship between the deformation and the contact pressure of the element is deduced. Combined with Preston equation, the temperature difference in the element and the surface accuracy of the element are finally connected, and verified by the surface shape measurement.
Experimental study on axially compressed square RC stub columns strengthened with prestressed CFRP strips
Authors: Wu Shengping , Han Bin , Wu Zhaoqi , Li Hua , Liu Han
Published: April 2020

Five square reinforced concrete (RC) stub columns were fabricated and experimental tested under an axial compression load in order to study the effectiveness of strengthening by using prestressed carbon fiber reinforced polymer (CFRP) strips. The specimens tested included one un-strengthened and four strengthened. Three specimens were strengthened by using prestressed strips, and the other one strengthened by using non-prestressed was used to compare. The prestress of the strip was achieved by tensed using a special device before it was pasted to the column. The experimental data such as the failure modes, load-displacement curves and strain distribution of CFRP strips were obtained. The effects of prestress magnitude of CFRP strips on the ultimate bearing capacity and deformation capacity of the specimens were analyzed. The results show that the prestress of CFRP strips can effectively increase the ultimate capacity and delay the crack occurrence of the specimens. And ultimate strain, plastic deformation of the specimens were also improved with increase of prestress magnitude of strip.
Resource Scarcity-Based Pricing for Cloud Manufacturing Service Platform
Authors: Wang Pan , Wen Peihan
Published: April 2020

Based on the architecture and key technologies of cloud manufacturing (CMfg) are becoming increasingly perfect, It is of great significance for the development and application of CMfg to study the resource pricing under the specific transaction environment of cloud manufacturing service platform (CMSP). Hence, an optimal pricing strategy model adapted to the CMSP environment was proposed in this paper. Firstly, the transaction process of CMSP is analyzed, then the static Bayesian model is selected and improved from three aspects. Finally, through the solution of the model and parameter analysis, the advantages of the model are proved, and the pricing strategy is provided for the platform resource providers.
Influence of Light and Temperature on Secondary Metabolites Production by Monascus Ruber in Rice Solid Cultures
Authors: Pang Hai-Yue , Lee Yu-Chieh , Wang Guey-Horng , Liaw Li-Ling , Chen Fang Fang , Chen Yu-Pei
Published: April 2020

Monascus species have been used in Chinese fermented foods such as Anka pork, and rice wine because of its bioactive substances including pigment, and monacolin K. In this study, the effect of light and temperature on red pigment, total polyphenols, DPPH radical scavenging, reducing ability and monacolin K of Monascus ruber BCRC31535 in rice solid culture was conducted. No obvious difference was observed by the DPPH radical scavenging assay whatever the cultural condition of light and temperature was performed. However, the results revealed that the red pigment, total polyphenols, reducing ability and monacolin K were the highest in the darkness at 30°C. Blue light and red light remarkably declined these secondary metabolites and antioxidant capacity, probably resulting from the induction of oxidative stress. By contrast, blue light can stimulate the production of red pigment and monacolin K at 20°C while red light can improve the reducing ability. Nevertheless, total polyphenols were not affected by light at the low temperature. Taking together, the temperature was also the interference factor in the solid-state culture of M. ruber BCRC31535, which influenced the light on the yield of secondary metabolites.
Effect of Electron Beam Irradiation on Chlorinated Polyethylene/Vinyl Acetate/Nitrile Rubber Blend System
Authors: Li Zhigang , Zhang Yubao , Zhao Hongtao
Published: April 2020

The blends of chlorinated polyethylene (CPE), ethylene-vinyl acetate copolymer (EVA) and nitrile rubber (NBR) were mixed and irradiated by electron beam. The effects of chlorinated polyethylene and electron irradiation on the structure and properties of blends were studied. The mechanical properties, crosslinking degree, crystallization properties, structure and morphology of EVA/NBR/CPE composites were characterized. The results showed that the addition of 25phr CPE had a significant effect on the capacity increase of EVA/NBR blend system, and the mechanical properties of the composites increased first and then decreased, the degree of crosslinking and the glass transition temperature increased while the crystallization temperature and enthalpy decreased. Electron beam irradiation induced hydrogen extraction reaction, formed a cross-linking structure, enhanced the phase interface bonding, and produced a synergistic effect with CPE volume-increasing EVA/NBR blend system.