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Safety modeling and simulation of multi-factor coupling heavy-equipment airdrop

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Chinese Journal of Aeronautics 2014年第5期27卷 1062-1069页

作者： zhang jiuxing Xu Haojun zhang Dengcheng Liu Dongliang Aerospace Engineering Institute Air Force Engineering University

Heavy-equipment airdrop is a highly risky procedure that has a complicated system due to the secluded and complex nature of factors＇ coupling. As a result, it is difficult to study the modeling and safety simulation of this system. The dynamic model of the heavy-equipment airdrop is based on the Lagrange analytical mechanics, which has all the degrees of freedom and can accurately pinpoint the real-time coordinates and attitude of the carrier with its cargo. Unfavorable conditions accounted in the factors＇ models, including aircraft malfunctions and adverse environments, are established from a man-machine-environment perspective. Subsequently, a virtual simulation system for the safety research of the multi-factor coupling heavy-equipment airdrop is developed through MATLAB/Simulink, C language and Flightgear software. To verify the veracity of the theory, the verification model is built based on dynamic software ADAMS. Finally, the emulation is put to the test with the input of realistic accident variables to ascertain its feasibility and validity of this method.

关键词： Heavy-equipment airdrop Modeling and simulation Multi-body system Multi-factor coupling Safety

Preparation and thermoelectric transport properties of Ba-, La- and Ag- doped Ca3Co4O9 oxide materials

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Journal of Rare Earths 2013年第8期31卷 778-783页

作者： zhang Feipeng LU Qingmei LITingxian zhang Xin zhang jiuxing SONG Xiaoyan Department of Applied Sciences Henan University of Urban Construction Pingdingshan 467036 China Key Laboratory of Advanced Functional Materi- als Chinese Ministry of Education College of Materials Science and Engineering Beijing University of Technology Beijing 100124 China College of Phys- ics and Electrical Engineering Anyang Normal University Anyang 455002 China

The Ba-, La- and Ag-doped polycrystalline Ca2.9M0.1Co4O9 （M=Ca, Ba, La, Ag） thermoelectric bulk samples were pre- pared via citrate acid sol-gel synthesis method followed by spark plasma sintering technique. The bulk samples were characterized and analyzed with regard to their phase compositions, grain orientations as well as microstructures. The high temperature thermoelec- tric transport properties of the bulk samples were studied in detail. All bulk samples were found to be single-phased with modified body texture. The electrical resistivity was modulated as a result of carrier concentration modification, however the carrier transport process was not influenced; the Seebeck coefficient was deteriorated simultaneously. The total thermal conductivity was remarkably reduced, on account of the decreasing of phonon thermal conductivity. The thermoelectric properties of the Ba-, La-, and Ag-doped bulk samples were optimized, and the Ba-doped Ca2.9Ba0.1Co4O9 system was found to have the highest dimensionless figure of merit ZT0.20 at 973 K, which was remarkably higher than that of the un-doped sample.

关键词： Ca3Co4O9 oxide Ca-site doping thermoelectric transport properties rare earths

Rapid synthesis of CoSb_3 by MA-SPS and its thermoelectric properties

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Rare Metals 2005年第3期24卷 257-260页

作者： LIU Kegao XIANG Dong zhang jiuxing School of Materials Science and Engineering Shandong University of Architecture and Engineering Jinan 250101 China School of Materials and Engineering Beijing University of Technology Beijing 100022 China

Bulk CoSb3 with single phase was synthesized by mechanical alloying and spark plasma sintering （MA-SPS）. The thermoelectric properties of bulk CoSb3 prepared by different technologies were investigated. All samples have the character of typical semiconductor electricity and their thermoelectric figures of merit （ZT） get the maximum values at 400℃. The highest ZT value is 0.0571, belonging to the sample sintered at 600℃ among all samples at all temperatures.

关键词： thermoelectric property spark plasma sintering CoSb3

Mechanism of conductive powder microstructure evolution in the process of SPS

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Science China(Technological Sciences) 2005年第3期48卷 258-269页

作者： SONG Xiaoyan LIU Xuemei zhang jiuxing College of Materials Science and Engineering Key Laboratory of Advanced Functional Materials of Ministry of Education of ChinaBeijing University of TechnologyBeijing 100022China

Spark plasma sintering(SPS)is an advanced sintering technology that has been recently developed in the *** to many reports about experimental investigations on the methods of new materials preparation,there are very few systematic studies on the special sintering mechanism of SPS *** the present paper,by using the pure electrolytic copper powders as the raw material,a series of sintering experiments have been designed and carried *** evolution of the powder microstructures during SPS has been systematically studied,and for the first time a“self-adjusting mechanism”of the microstructure evolution is proposed,from which the essential for the advantages of materials preparation by SPS in the respects of high density,homogeneity and fine grain structure can be well *** addition,the changes of the relative density during SPS are quantitatively predicted by a theoretical model and confirmed by the experimental measurements.

关键词： spark plasma sintering microstructure evolution sintering mechanism

Structure and magnetic properties of Mn_(1.2)Fe_(0.8)P_(0.76)Ge_(0.24) annealed alloy

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Rare Metals 2012年第4期31卷 336-338页

作者： Xu, Hang Yue, Ming Zhao, Chuan zhang, Dongtao zhang, jiuxing College of Materials Science and Engineering Beijing University of Technology Beijing100124China

Bulk Mn_(1.2)Fe_(0.8)P_(0.76)Ge_(0.24) alloy was prepared by mechanical milling and subsequent spark plasma sintering *** of annealing on the structure and magneto-caloric properties of the alloy was *** results show that both sintered and annealed samples possess a hexagonal Fe_2P-type crystal *** annealing,ferromagnetic impurity Fe_3Mn_4Ge_6,which exists in the sintered sample,was eliminated from the ***,the lattice constants a and c change noticeably,leading to a decrease in c/a ratio,while the cell volume almost remains *** a result,the Curie temperature of the alloy increases from 253 K to 298 K,but the maximum magnetic entropy change decreases from 37.5 to 11.7 J·kg·K^(-1) for 2 T magnetic field *** the other hand,the thermal hysteresis of M-T curves around T_C upon heating and cooling is 14 and 8 K for the as-sintered and the annealed sample,respectively,showing evident change.

关键词： Mn_(1.2)Fe_(0.8)P_(0.76)Ge_(0.24) lattice constants isothermal entropy change thermal hysteresis

Microstructure,Properties,and Grain Growth Kinetics of Mo-5Ta Refractory Sputtering Targets Prepared by SPS

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Journal of Wuhan University of Technology(Materials Science) 2023年第6期38卷 1248-1254页

作者： LIU Dawei YANG Xiaolong HUANG Lei PAN Yafei zhang jiuxing School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Engineering Research Center of High-Performance Copper Alloy Materials and Processing Ministry of EducationHefei University of TechnologyHefei 230009China

Mo-5Ta targets were prepared by the spark plasma sintering(SPS)technology under the sintering temperatures of 1400-1600℃,the holding times of 0-20 min,and the axial pressure of 30 *** microstructure,performance,and grain growth kinetics of Mo-5Ta sputtering targets were *** the increase of sintering temperatures and times,Ta can more dissolve in Mo and form a Mo(Ta)solid *** grain sizes of Mo-5Ta targets remain unchanged at low temperatures(1400-1500℃)while increasing significantly at high temperature(1600℃)with the extension of the holding *** addition,the densities and Vickers hardness(HV_(0.5))first ascend and then decrease with sintering *** thermal conductivity is positively correlated with the grain size and density,as a result of their joint *** on the comprehensive analysis,the grain growth is dominated by the combination of boundary diffusion and volume *** n=2,the activation energies of grain growth under holding times of 5,10,20 min are calculated as 762.70,617.86,and 616.52 kJ/mol,respectively.

关键词： SPS Mo-5Ta targets structure properties grain growth kinetics

Spark Plasma Sintering Bulk Sm2 Fe17NxMagnets

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Journal of Rare Earths 2004年第Z1期22卷 73-75页

作者： Yue Ming zhang Dongtao Ji Yongcheng zhang jiuxing Key Laboratory of Advanced Functional Materials Ministry of Education Beijing University of TechnologyBeijing 100022 China

High performance Sm2Fe17Nx magnetic powders were fabricated by ball-milling method and were compacted using spark plasma sintering(SPS) *** of processing conditions on the magnetic properties and decomposition dynamic of the magnets were *** is found that higher sintering temperature improves the densification of the magnets, while deteriorates their magnetic properties simultaneously due to the decomposition of the *** at lower temperature can preserve the crystal structure of Sm2Fe17Nx compound, while the powders cannot be consolidated into a fully dense *** increased compressive pressure leads to better magnetic properties and higher density for the magnet at the same sintering temperature.

关键词： Sm2Fe17Nx magnet spark plasma sintering(SPS) decomposition dynamic densification

EFFECTS OF Y₂O₃ AND CeO₂ ON PROCESSING AND CHARACTERISTICS OF TUNGSTEN ELECTRODES

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中国有色金属学会会刊：英文版 1999年第2期9卷 118-122页

作者： Chen, Ying Nie, Zuoren Zhou, Meiling zhang, jiuxing Zuo, Tieyong Beijing Polytechnic Univ Beijing China

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１ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｒｅｃｅｎｔｙｅａｒｓ，ｔｕｎｇｓｔｅｎｅｌｅｃｔｒｏｄｅｍａｔｅｒｉａｌｓｃｏｎｔａｉｎｉｎｇｏｎｅｋｉｎｄｏｆｒａｒｅｅａｒｔｈｍｅｔａｌｏｘｉｄｅａｓＬａ２Ｏ３，ＣｅＯ２ａｎｄＹ２Ｏ３，ｈａｖｅｂｅｅｎｄｅｖｅｌ...

关键词： Y2O3CeO2tungsten electrodearcstartingconsumption

Preparation of ultrafine WC-Co cermets by combining pretreatment and consolidation with spark plasma sintering

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Rare Metals 2009年第4期28卷 391-395页

作者： ZHAO Shixian SONG Xiaoyan WANG Mingsheng LIU Guoquan zhang jiuxing Key Laboratory of Chinese Ministry of Education for Advanced Functional Materials School of Materials Science and Engineering Beijing University of Technology Beijing 100022 China School of Matertals Science and Engmeering University of Science and Technology Beijing Beijing 100080 China

Ultrafine-grained WC-Co bulk materials were prepared by a new method that contains pretreatment of the milled powder mixture and subsequent spark plasma sintering （SPS）. Ball milling parameters and the pretreatment temperature have significant effects on the microstructure and properties of WC-Co cermets. The prepared cermets have a mean grain size of less than 0.5 μm even with a pretreatment temperature as high as 1300℃. The WC-10wt.%Co cermet bulk prepared by the optimized milling, pretreatment, and SPS processing achieves excellent mechanical properties with a Vickers hardness of HV 1643, a fracture toughness of 13.1 MPa.m^1/2 and a transverse rapture strength of 3100 MPa.

关键词： cermets sintering pretreatment microstructure mechanical properties