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Table of Content

    01 March 2018, Volume 52 Issue 2 Previous Issue    Next Issue
    Research on Motion Relationship Between the Surface Boat and the Wave-Propelled Sub in Wave Glider System
    ZHANG Chengyi, XU Xuesong
    2018, 52 (2):  127-132.  doi: 10.16183/j.cnki.jsjtu.2018.02.001
    Abstract ( 1040 )   Save
    To study motion relationship between the surface boat and the wave-propelled sub in wave glider system, the cable connecting these two parts is divided into several micro segments for analysis. The motion relationship can be obtained by solving dynamic equilibrium equations of all segments. According to the numerical results, the horizontal velocity of wave glider varies continuously and steadily, and the horizontal velocity range of the surface boat is larger than that of the wave-propelled sub. Because of the flexibility of the cable, wave glider horizontal velocity is easy to adjust as the wave changes. Moreover, the short cable is in favor of motion transmission.
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    Change Law of the Swelling Deformation of GMZ Bentonite Corroded by Alkaline Pore Water
    XIANG Guosheng1,2,XU Yongfu2,WANG Yi1,FANG Yuan1
    2018, 52 (2):  141-146.  doi: 10.16183/j.cnki.jsjtu.2018.02.003
    Abstract ( 958 )   Save
    The GMZ01 bentonite was mixed with 1 mol/L NaOH solution and sealed tightly. After different preset time of placement, the swelling deformation tests of specimens were produced in distilled water to research the variation of swelling characteristics influenced by the alkaline pore water during long time, and the swelling property was found to decrease with the reaction time. Mineral composition analysis of the specimens reveals a decrease in the montmorillonite content with reaction duration while an increase in the feldspar content, and suggests that during the longtime exposure to NaOH solution, the montmorillonite dissolute gradually to precipitate the non-swelling minerals, leading to the swelling attenuation. The swelling fractal model was employed to analyze the swelling test results, the montmorillonite void ratio of specimens during different reaction time can be expressed by a unique em-pe fractal relationship using an effective stress incorporating with osmotic suction of pore water. It suggests the swelling deformation of specimens corroded by NaOH solution are mainly dependent on the montmorillonite content with few variation in the other properties of montmorillonite.
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    Experimental Study of Creep Properties of Ethylene Tetrafluoroethylene Foil
    LI Yipoa,HU Jianhuia,b,c,CHEN Wujuna,YIN Yuea,YANG Deqingb,c
    2018, 52 (2):  147-151.  doi: 10.16183/j.cnki.jsjtu.2018.02.004
    Abstract ( 1020 )   Save
    Creep tests on twelve groups of ethylene tetrafluoroethylene (ETFE) foil samples of 250μm thick were conducted at different temperatures and stresses. According to the test results, this paper employed the logarithmic fitting of time-deformation relations, and analyzed the parameter variations under different test conditions. The relationship between creep strain, stress and temperature was established and used to describe the creep properties of ETFE foils. It was found that a large creep strain existed at high temperature or large stress, and that the relationship between strain, stress and temperature was nonlinear. Moreover, the creep strain kept small if the temperature was under 40 ℃ and the stress was under 6MPa while large creep strain was observed at high temperature and stress.
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    Quasi-Static Test of Q345 Equal Angles Under the Coupling Action of Corrosion and Fatigue Vibration
    ZHANG Chuntao1,LI Zhengliang2,WANG Ruheng1
    2018, 52 (2):  152-162.  doi: 10.16183/j.cnki.jsjtu.2018.02.005
    Abstract ( 884 )   Save
    The coupling damage model of corrosion and fatigue is established considering the interaction between environmental corrosion and fatigue vibration. This model is applied to study the deterioration law of the mechanical property of Q345 equal angles. Firstly, the environmental corrosion model was established according to the annual rainfall time of the target areas, and the evolutionary model for evaluating fatigue damage was presented by combining energy dissipation model with Paris formula of fatigue crack growth. Then, a coupling factor was proposed to effectively measure the relationship between corrosion and fatigue damage. Based on this coupling factor, the coupling damage model was derived by combining the corrosion and fatigue damage models. Finally, the quasi-static test of twenty Q345 equal angles with 70mm×5mm specification was carried out, and the effect laws of the bearing capacity and energy dissipation performance of angle steels under the corrosion, fatigue and corrosion fatigue coupling actions were analyzed, and the coupling damage degradation model of each parameter was established. The results show that the coupling action of corrosion and fatigue promote the development of component damage, but current design specifications and studies rarely consider this effect. The bearing capacity, stiffness, hysteretic curve shape and cycle times of Q345 angle steels changed obviously due to the coupling action of corrosion and fatigue. Moreover, under the coupling action of 12 hours accelerated corrosion and 4.0×104 times fatigue vibration, the degradation rates of ductility coefficient and cumulative energy dissipation parameter were 11.1% and 7.7% more than the total the damage caused by the individual action of corrosion and fatigue damage.
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    Psychological Characteristics of Drivers in the Stress Scene Based on Heart Rate Variability
    LI Xiansheng1,MENG Fansong1,ZHENG Xuelian1,REN Yuanyuan1,YAN Jiahui2,WU Ping3,ZHANG Jinghai1
    2018, 52 (2):  163-168.  doi: 10.16183/j.cnki.jsjtu.2018.02.006
    Abstract ( 1092 )   Save
    In order to study the psychological characteristics of drivers under stress conditions, the electrocardiogram (ECG) data of drivers under different stress scenarios were analyzed. Using the Ergo LAB human environment synchronization platform, the driver’s heart rate variability (HRV) time domain data and frequency domain data were extracted, and the appropriate ECG characteristics were selected as indicators of analysis. By the statistical analysis method, the ECG data of the subjects were studied, and the psychological characteristics of the drivers under stress scenarios were obtained. It shows that in terms of the rate of increase in heart rate, different stress scenarios will have a significant impact on the driver’s heart rate growth. Drivers are sensitive to the target of pedestrians, bicycles, and less sensitive to other objects like the weather and motor vehicles. In terms of HRV time domain characteristics, the driver has a longer degree of tension about pedestrians and bicycles, and has intermittent tension about the weather or the vehicle. In terms of HRV frequency domain characteristics, the driver’s mental workload increases when he encounters pedestrians and bicycles, and reduces when he encounters motor vehicles and external weather conditions.
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    Lightweight Approximation of Hull Surface Based on Non-Uniform Rational B-Spline
    ZHANG Yanrua,LIN Yana,b,LU Conghonga,JI Zhuoshanga
    2018, 52 (2):  169-175.  doi: 10.16183/j.cnki.jsjtu.2018.02.007
    Abstract ( 1149 )   Save
    During the processes of digital ship design, there are too many control points on the hull surface based on interpolation section curves, which are disadvantageous to the hull surface fairing and modification. The shape of hull surface, based on non-uniform rational B-spline section curves, is uncontrollable. To solve the forementioned problems, a design of lightweight approach of hull surface approximation is proposed. The hull surface is generated by two steps of section curves approximation. In step one, the equivalent chord deviation curve discretization method is applied to the curve approximation. In step two, the optimization approximation model is constructed with the knots of section curves as the design vari-ables. The objective function is set to minimize the sum of the approximate error of all section curves in the least-squares sense. According to the character of this problem, the genetic algorithm with adaptively alterable chromosome length is improved and applied to solve this optimization problem. The instances of the hull surface approximation and design for full-scale ship indicate that it is feasible and can satisfy the requirements of the engineering design for hull surface approximation. Applying this method, the data used for hull surface design and approximation can be reduced. And it can provide a reference for the lightweight design of other similar complex surface.
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    Polymer-Metal Direct Molding Technology
    FAN Cong,HU Guanghong,LING Chengzhi
    2018, 52 (2):  176-181.  doi: 10.16183/j.cnki.jsjtu.2018.02.008
    Abstract ( 1189 )   Save
    Polymer-metal direct forming, as a kind of forming process which combines metal and polymer directly, has a wide range of development prospects because of its combination of metal and polymer material characteristics. This paper mainly introduced the theory of polymer-metal direct molding technology and its key technology as well, summarized the latest research progress of bonding strength of compounds, and pointed out some key factors influencing the bonding strength. These lay a good foundation for the future research on bonding strength of the composite parts.
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    Approach of Design of Process Dimension for Hemming of Aluminum Alloys
    YANG Ke1,ZHAO Yixi1,FENG Changwen2,YU Zhihua2
    2018, 52 (2):  182-187.  doi: 10.16183/j.cnki.jsjtu.2018.02.009
    Abstract ( 1317 )   Save
    Through simulation experiments on hemming qualities for curved surface hemming and curved edge hemming under different flanging sheet sizes, limit values of flanging sheet size are decided for different curvature radius. The values of corresponding flanging length and hemming width are given then. A hemming feature panel is designed based on the standards. The experiment results demonstrate that, the values of designed parameters are reasonable and the feature panel obtains favourable hemming effect.
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    A Comparative Study on Tissue Injury Caused by Implantation Based on Electrode with the Capability of Micro-Motion Attenuation
    TANG Jiaqi,ZHANG Wenguang,CAI Fenglong,YIN Xuele
    2018, 52 (2):  188-193.  doi: 10.16183/j.cnki.jsjtu.2018.02.010
    Abstract ( 944 )   Save
    In order to attest the validity of neural electrode with the capability of micro-motion attenuation, comparative studies based on evaluation system for testing tissue injury were conducted. Different implantation parameters (depth: 1.5, 3, 4.5mm; insertion speed: 50, 100, 500, 1000, 1500, 2000μm/s) were set respectively for the experiment with the micro-motion attenuation electrode and the common electrode to study the affects of the two electrodes. This method is controlable, and can effectly avoid the uncertainty of vivo experiments. The conclusion was found that the modified electrode is not better than the reference electrode at the depth of 1.5mm. But it has obvious advantage on decreasing the tissue injury when the insertion depths are 3mm and 4.5mm.
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    Design and Evaluation of a Novel Splint Used in Distal Radius Fracture
    HE Yuntao1,KONG Bo2,3,XI Xiaobing2,3,LUO Yun1
    2018, 52 (2):  194-199.  doi: 10.16183/j.cnki.jsjtu.2018.02.011
    Abstract ( 1180 )   Save
    A novel modularized splint was designed to have functions of fixation, traction and flexibility following the principle of modern osteosynthesis, to overcome the shortage of the common non-surgical treatment of distal radius fracture. A concrete design with detailed kinematic and mechanical analysis was put forward. Then experiments which built relationships between displacement with skin deformation and moment of wrist rotation with angle were set. The results indicated that the novel splint was able to realize traction by displacement, and had sufficient stiffness in fixation mode, while had a changeable range of motion and stiffness in flexible mode. Therefore, the effectiveness of the mechanism could be proved and the foundation of further research was laid.
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    Establishment of an In Vitro Cell Heating System Based on 3D Cell Culture
    JIANG Zuomin,ZOU Jincheng,ZHANG Aili
    2018, 52 (2):  200-206.  doi: 10.16183/j.cnki.jsjtu.2018.02.012
    Abstract ( 839 )   Save
    To deal with the limitation of cell thermal experiment, which cannot simulate the complex micro-environment in vivo and may influence the accuracy of the experiment, the present study tried to design a petri dish which is able to heat cells both in 2D and 3D forms. At the same time, operators could constantly monitor the changes of cells during and after heating process through the microscope. Verified by experiments, this petri dish has the superiority of biocompatibility, visuality, accuracy and stability. While the 3D cell culture is used to simulate the micro-environment of the tumor in vivo, this is an effective method for cell heating and culturing.
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    An Asymmetry Cascaded Multilevel Inverter with Hybrid Power Supply
    ZHANG Dan,WANG Jie
    2018, 52 (2):  207-213.  doi: 10.16183/j.cnki.jsjtu.2018.02.013
    Abstract ( 697 )   Save
    This paper presents an asymmetry hybrid cascaded multilevel inverter. Firstly, the topology of the proposed inverter is introduced theoretically. Then, taking seven-level output for example, using the phase opposition disposition pulse width modulation (PODPWM) combining with feedback control method, the capacitor voltage is controlled at the desired value by adjusting the switching logic, so as to achieve the purpose of making the output seven-level. Finally, the inverter and control circuit is built in MATLAB, and the simulation results support the proposed inverter and the control method.
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    A Similar Duplicate Record Detection Algorithm for Big Data Based on MapReduce
    SONG Renjie1,YU Tong1,CHEN Yuhong2,CHEN Yuyang2,XIA Bin2
    2018, 52 (2):  214-221.  doi: 10.16183/j.cnki.jsjtu.2018.02.014
    Abstract ( 1103 )   Save
    In view of the characteristics of multi-source, high dimension and large volume of big data, traditional algorithms have been unable to effectively complete the similar duplicate records detection for big data, therefore, a new parallel algorithm MP-SYYT for the detection of similar duplicate records of big data in the cloud environment is put forward. Firstly, Institute of computing technology chinese lexical analysis system (ICTCLAS) word segmentation technology, Delphi method and team frequency Inverse document frequency (TF-IDF) algorithm are used to improve the traditional SimHash algorithm, and these methods effectively solve the insufficiency of the traditional one, such as the low extraction speed, the imprecision of the keywords, and the low accuracy on weight calculation. Secondly, the inversed file retrieval algorithm is used to optimize the traditional SimHash algorithm to improve the matching efficiency of similar duplicate records. Finally, the Map function and the Reduce function based on the improved SimHash algorithm are defined on a cloud platform to realize the parallel detection of big data and the direct output of duplicate records in cloud environment with MapReduce model, and an experimental analysis about the multi-source measured data is made on a Hadoop platform. The results show that MP-SYYT is an efficient and accurate algorithm with good scalability and acceleration ratio, and it is suitable for similar duplicate record detection of big data.
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    Combined Machining of 50%SiCp/Al Composites with Electrical-Arc-Milling and Milling-Grinding
    LIU Xiao1,CHEN Jipeng2,GU Lin2,CHEN Fengfan1,WANG Wei1
    2018, 52 (2):  222-227.  doi: 10.16183/j.cnki.jsjtu.2018.02.015
    Abstract ( 977 )   Save
    To solve the problems of SiCp/Al composites processing, such as low efficiency and limited surface quality, a processing method was proposed by combined electrical-arc-milling and milling-grinding. The experimental results show that the obtained material remove rate was up to 6300mm3/min and the thickness of recast layer was below 100μm by the electrical-arc-milling to the rough machining of 50%SiCp/Al composites (volume fraction). On the other hand, when the milling-grinding was applied to the finishing of 50%SiCp/Al composites, the surface defects such as edge breakage can be avoided, and the surface roughness (Ra) was 0.8μm. The validity of the combined manufacture method was proved with the machining tests for the bracket IR seeker, which was made of 50%SiCp/Al composites.
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    Prediction for Fatigue Life of Al-Zn-Mg Alloy Based on Grey System Theory
    TANG Hongyuana,ZHANG Zhenb,c,DENG Yunlaia,b,c,YE Lingyinga,QIAN Pengweib,c,ZHAO Longa
    2018, 52 (2):  228-232.  doi: 10.16183/j.cnki.jsjtu.2018.02.016
    Abstract ( 911 )   Save
    The S-N curve was obtained by tests based on the fatigue property of Al-Zn-Mg alloy plates. The grey system theory model was applied in predicting fatigue life of the plates while the prediction was evaluated and compared with the S-N curve. The results show that the predicative values of the gray system model are close to those of the S-N curve, and the equal dimension gray model GM(1,1) has a higher prediction accuracy than the original model GM(1,1) in multi-step prediction. It provides a better estimation of the fatigue life of Al-Zn-Mg aluminum alloy plates.
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    E-Learning User Acceptance Model in Business Schools Based on UTAUT in the Background of Internet Plus
    WU Qionglei,ZHANG Pengzhu
    2018, 52 (2):  233-241.  doi: 10.16183/j.cnki.jsjtu.2018.02.017
    Abstract ( 1063 )   Save
    In view of the current situation that E-learning usage rate is still not high in Chinese business schools, a research model of the acceptance of E-learning system in business schools is proposed from the viewpoint of teachers. Based on the technology acceptance and the unified theory of acceptance and use of technology (UTAUT) series model and combined with the features of business school teaching, the empirical analyses are carried out on the research model and hypotheses. The structural equation analysis results show that the teachers’ user characteristics (mainly referring to teachers’ skill, attitude, consciousness of the protection of intellectual property rights, etc.), performance expectancy, online course features, facilitating conditions, effort expectancy and social influence are the influence factors on the intention and behavior of E-learning system use, in which the teachers’ user characteristics, the performance expectancy and the online course features are the determining factors in the adoption intention of E-learning system. This study discusses the differences of using E-learning of overseas education background and gender. This study also gives some strategic suggestions on the construction and promotion of E-learning system in business schools in China, and has a certain reference value for the business schools to promote E-learning system.
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    Analysis About the Influence Factors of the Network Group Buying Behavior
    QUAN Lin1,GU Feng2,LI Qing3
    2018, 52 (2):  242-246.  doi: 10.16183/j.cnki.jsjtu.2018.02.018
    Abstract ( 992 )   Save
    Based on information sharing influence on consumer activities, the paper studies how consumers group buying behavior changes and who dominated, which are difficult points in the process of group behavior research. In the online purchasing system, time and resource are limited, and both sides in business have marginal effect with the increase of negotiation time. When new consumers join in the network, other consumers will shorten the negotiation time. Meanwhile, new consumers without group purchase experience will shorten the negotiation time, and quickly join in the group activities.
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    Impact of Crisis Response Strategies on the Purchase Intentions Based on the Moderator of the Enterprise Reputation
    JI Dan1,GUO Zheng2
    2018, 52 (2):  247.  doi: 10.16183/j.cnki.jsjtu.2018.02.019
    Abstract ( 694 )   Save
    The impact of crisis response strategies on the purchase intentions is measured on 197 samples participating in a between-subjects experiment design which includes 3 response strategies (denial strategy, reticence strategy and recall strategy) and 2 reputations (good or bad). The results show that different response strategies have different effects on purchase intentions. However, the reticence strategy is the worst one. The enterprise reputation plays a moderating role in the relationship. The denial strategy is the best practice to the enterprise which has good reputation, while the recall strategy is the best practice to the enterprise which has bad reputation.
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