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Diesel and welding aerosols in an underground mine

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International Journal of Mining Science and Technology 2020年第4期30卷 449-454页

作者： Aleksandar D.Bugarski Teresa L.Barone Jon A.Hummer National institute for Occupational Safety and Health Pittsburgh Mining Research DivisionPittsburghPA 15236USA

researchers from the National institute for Occupational Safety and Health(NIOSH)conducted a study in an isolated zone of an underground mine to characterize aerosols generated by:(1)a diesel-powered personnel carrier vehicle operated over a simulated light-duty cycle and(2)the simulated repair of existing equipment using manual metal arc welding(MMAW).Both the diesel-powered vehicle and MMAW process contributed to concentrations of nano and ultrafine aerosols in the mine *** welding process also contributed to aerosols with electrical mobility and aerodynamic mobility count median diameters of approximately 140 and 480 nm,*** welding particles collected on the filters contained carbon,iron,manganese,calcium,and aluminum.

关键词： Diesel aerosols Welding aerosols Underground mining Size distribution

Effect of current on the microstructure and performance of (Bi_2Te_3)_(0.2)(Sb_2Te_3)_(0.8) thermoelectric material via field activated and pressure assisted sintering

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Journal of Semiconductors 2011年第7期32卷 9-13页

作者：陈瑞雪孟庆森樊文浩王忠 College of Material Science and Engineering Taiyuan University of Technology General research institute for Nonferrous Metals

（Bi_2Te_3）_（0.2）（Sb_2Te_3）_（0.8） thermoelectric material was sintered via a field activated and pressure assisted sintering（FAPAS） *** applying different current intensity（0,60,320 A/cm^2） in the sintering process,the effects of electric current on the microstructure and thermoelectric performance were *** demonstrated that the application of electric current in the sintering process could significantly improve the uniformity and density of（Bi_2Te_3）_（0.2）（Sb_2Te_3）_（0.8） *** the current intensity was raised to 320 A/cm^2,the preferred orientation of grains was ***,positive effects on the thermoelectric performance of applying electric current in the sintering process were also *** increase of 0.02 and 0.11 in the maximum figure of merit ZT value could be acquired by applying current of 60 and 320 A/cm^2,respectively.

关键词： thermoelectric material (Bi_2Te_3)_(0.2)(Sb_2Te_3)_(0.8) microstructure performance current field activated and pressure assisted sintering

Hydrothermal Synthesis, Crystal Structure and Magnetic Property of a Novel Mixed Valence Decatungstate: [Cu(2,2′-bipy)_2]_2Na_2W_6~VW4^(VI)O_(30)·2H_2O

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Chinese Journal of Structural Chemistry 2008年第1期27卷 57-62页

作者：李涛海吕健高水英曹荣 State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences

A novel Cu（II）-2,2＇-bipy-supported （bipy = bipyridine） mixed valence decatungstate, [Cu（2,2＇-bipy）2]2Na2W6^VW4^VIO30·2H2O 1, has been synthesized and structurally characterized by X-ray analysis. The crystal of 1 is of triclinic, space group P1^- with a= 10.9393（10）, b = 12.0492（2）, c = 12.3783（2）A, a = 80.631（10）, β= 70.226（10）, γ= 72.329（9）^o, V = 1459.64（4）A^3, Z = 1, Dc = 3.582 g/cm^3, F（000） = 1404, R = 0.0553 and wR = 0.1242 for 4607 observed reflections （I 〉 2σ（I））. The EPR spectrum of 1 indicates that its unpaired electrons are placed in the dx2-y2 orbital of the ground state of Cun. Furthermore, compound 1 shows an antiferromagnetic interaction.

关键词： crystal structure decatungstate mixed valence magnetic property

Design and Realization of a New Type of Constant Current Source with Small Current and High Precision 36

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Design and Realization of a New Type of Constant Current Sou...

Water Gas Shift Reaction： A Monte Carlo Simulation

第36届中国控制会议

作者： Jun xiao Li Xue mei Wang Zhe Xu Xi’an High Tech research institute

ISBN: (纸本)9781538629185

Using constant current source as the excitation signal is an effective method for system testing of the *** present,the constant current source circuit built by TL431 voltage regulator does not meet the system test requirements of the aircraft under the condition of small current *** when the temperature span is large,the working circuit does not have the ability to inhibit the temperature drift,of which the temperature drift is *** this paper,the constant current source circuit built by TL431 voltage regulator is *** OP77 and π-type filter circuit to ensure the output accuracy,the design of the resistor network can achieve complementary temperature *** drift is reduced by adjusting the appropriate compensation ***,the superior performance of the improved constant current source is verified by simulation and experiment.

关键词： Small current High precision Low temperature drift Constant current source

来源： cnki会议评论

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Chinese Physics Letters 2006年第9期23卷 2602-2605页

作者： Waqar AHMAD Akhtar HUSSAIN Physics research Division Pakistan Institute of Nuclear Science and Technology PO Nilore Islamabad Pakistan

The water gas shift （WGS） reaction is reacts with water on a catalytic surface a process of industrial importance to form CO2 and H2. We study this In this reaction carbon monoxide reaction with thermal （Langmuir- Hinshelwood） and non-thermal （precursor and Eley-Rideal） reaction mechanisms using the techniques of Monte Carlo computer simulation. The details of surface coverages and production rates are given as a function of CO partial pressure. The diffusion of species on the surface as well as their desorption from the surface is also introduced to include temperature effects. The phase diagrams of the system have been drawn to observe the behaviour of reacting species on the surface. The study reveals that the production rates are higher for non-thermal precursor mechanism and are in agreement with the experimental finding.

关键词： KINETIC PHASE-TRANSITIONS SURFACE-REACTION MODEL HETEROGENEOUS CATALYSIS NITROGEN CHEMISORPTION MECHANISM TUNGSTEN DIAGRAM FACE

Robust monocular SLAM towards motion disturbance

维普期刊数据库评论

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维普期刊数据库

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Chinese Science Bulletin 2014年第17期59卷 2050-2056页

作者： Wei Liu Nanning Zheng Zejian Yuan Pengju Ren Tao Wang institute of Artificial Intelligence and Robotics Xi’an Jiaotong University AVIC Xi’an Flight Automatic Control research institute

The standard extended Kalman filter-based simultaneously localization and mapping(EKF-SLAM)algorithm has a drawback that it could not handle the sudden motion caused by the motion *** prevents the SLAM system from real *** techniques have been developed to make the system more robust to the motion *** this paper,we propose a robust monocular SLAM ***,when the motion model-based system failed to track the features,a KLT tracker will be activated for each ***,the KLT tracked features are used to update the camera ***,the difference between the camera states and the predictions is used to adjust the input motion ***,we do the standard EKF-SLAM with the new input motion *** order to make the system more reliable,a joint compatibility branch and bound algorithm are used to check the outliers,and an IEKF filter is used to make the motion estimation smoother when the camera encounters sudden *** experiments are done on an image sequence caught by a shaking hand-held camera,which show that the proposed method is very robust to large motion disturbance.

关键词：扰动运动 SLAM 干扰鲁棒性分支定界算法扩展卡尔曼滤波照相机地图创建

Design for Isothermal Forging of Ti-46.5Al-2.5V-1.0Cr-0.3Ni Alloy

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Journal of Iron and Steel research International 2010年第8期17卷 67-73页

作者： SI Jia-yong HAN Peng-biao ZHANG Ji institute of Processing Technologies of Materials Central South University of Forestry and TechnologyChangsha 410004HunanChina High Temperature Material research Division Central Iron andSteel Research InstituteBeijing 100081China

The three-dimensional finite element method was utilized to investigate the isothermal forging of Ti-46.5Al-2.5V-1.0Cr-0.3Ni（atomic percent,%）*** partition of height reduction,effective strain,and damage of the alloy during the forging were *** simulation results were verified by *** results show that large plastic deformation can improve the homogeneity of the deformed microstructure and the higher accumulative height reduction can be achieved through two-step *** the isothermal forging of two-step reduction of 60%＋62.5%（total height reduction of 85%）,the entire forged pancake can acquire refined microstructure and expand the uniform flow zone to almost the entire volume.

关键词： titanium aluminide isothermal forging multistep forging FEM simulation

Optimization of the cavity beam-position monitor system for the Shanghai soft X-ray free-electron laser user facility

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Nuclear Science and Techniques 2022年第10期33卷 22-32页

作者： Jian Chen Yong-Bin Leng Lu-Yang Yu Long-Wei Lai Ren-Xian Yuan Shanghai Advanced research institute Chinese Academy of SciencesShanghai 201204China Shanghai institute of Applied Physics Chinese Academy of SciencesShanghai 201800China

To achieve high-efficiency operation of the highgain free-electron laser(FEL),the electron beams and radiated photon beams need to be overlapped precisely and pass through the entire undulator ***,a high-resolution beam-position monitor(BPM)is required.A cavity BPM(CBPM)with a resonant cavity structure was developed and used in the Shanghai Soft X-ray FEL(SXFEL)test facility and can achieve a position resolution of<1μ*** construction and operation of the SXFEL user facility also bring about higher requirements for beamposition *** this case,the factors that affect the performance of the CBPM system were further *** included the amplitude and phase stability of the local oscillator,stability of the trigger signal,performance of the radio frequency front-end,signal processing electronics,and signal processing *** on the upgrade and optimization of the system,a beam test platform was built at the end of the linear acceleration section of the SXFEL,and the experimental results show that the position resolution of the system can reach 177 nm at a bunch charge of 500 pC,and the dynamic range is controlled within±300μm,and the relative measurement uncertainty of the bunch charge can reach 0.021%,which are significant improvements compared to the attributes of the previous system.

关键词： Cavity BPM SXFEL System optimization Position resolution Measurement uncertainty Algorithm

Performance improvement of optimization solutions by POD-based data mining

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Chinese Journal of Aeronautics 2019年第4期32卷 826-838页

作者： Yanhui DUAN Wenhua WU Peihong ZHANG Fulin TONG Zhaolin FAN Guiyu ZHOU Jiaqi LUO Computational Aerodynamics institute China Aerodynamics Research and Development Center School of Aeronautics and Astronautics Zhejiang University

The performance of an optimized aerodynamic shape is further improved by a second-step optimization using the design knowledge discovered by a data mining technique based on Proper Orthogonal Decomposition(POD) in the present study. Data generated in the first-step optimization by using evolution algorithms is saved as the source data, among which the superior data with improved objectives and maintained constraints is chosen. Only the geometry components of the superior data are picked out and used for constructing the snapshots of POD. Geometry characteristics of the superior data illustrated by POD bases are the design knowledge, by which the second-step optimization can be rapidly achieved. The optimization methods are demonstrated by redesigning a transonic compressor rotor blade, NASA Rotor 37, in the study to maximize the peak adiabatic efficiency, while maintaining the total pressure ratio and mass flow ***, the blade is redesigned by using a particle swarm optimization method, and the adiabatic efficiency is increased by 1.29%. Then, the second-step optimization is performed by using the design knowledge, and a 0.25% gain on the adiabatic efficiency is obtained. The results are presented and addressed in detail, demonstrating that geometry variations significantly change the pattern and strength of the shock wave in the blade passage. The former reduces the separation loss,while the latter reduces the shock loss, and both favor an increase of the adiabatic efficiency.

关键词： Aerodynamic shape optimization Computational fluid dynamics Data mining Particle swarm optimization Proper Orthogonal Decomposition Transonic flow Turbomachinery