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The influence of impurity on the critical thickness of the CeO_2 buffer layer for coated conductors

Science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 993-996页

作者： PAN Min1, HUANG Zheng2, MA HuanFeng2, QIANG WeiRong2, WEI LianFu1, WANG Long2 & ZHAO Yong1,3 1 Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of china), Superconductivity R&D Center (SRDC), southwest jiaotong university, chengdu 610031, china 2 school of Physical Science and Technology, southwest jiaotong university, chengdu 610031, china 3 Superconductivity Research Group, school of Materials Science and engineering, university of New South Wale, Sydney, 2052 NSW, Australia Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of china) Superconductivity R&D Center (SRDC) Southwest Jiaotong University Chengdu China school of Physical Science and Technology Southwest Jiaotong University Chengdu China Superconductivity Research Group School of Materials Science and Engineering University of New South Wale Sydney Australia

The lattice parameters, band structure, density of state and elastic constant of RE-doped CeO2 (RE=Sm, Gd, Dy), the buffer material for coated HTS conductors, are calculated using the plane-wave method with pseudopotentials based on the density functional theory (DFT) of first-principle. The rule and mechanism of the effect of rare earth impurity on the critical thickness of the CeO2 buffer layer are investigated. It is found that, in the range of the calculation, the changes of the lattice volume V and elastic constant E of CeO2 with the impurity are mainly determined by the increased electrons ne of the system. The relationship of the elastic constant E and increased electrons ne is established. It is indicated that the critical thickness of the CeO2 single buffer layer doped with Sm, Gd, and Dy may be enhanced by 22%, 43% and 33%, respectively.

关键词： CeO2 first principle critical thickness elastic constants

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3D thermo-hydro-mechanical-migratory coupling model and FEM analyses for dual-porosity medium

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Science china(Technological Sciences) 2010年第8期53卷 2172-2182页

作者： ZHANG YuJun 1&ZHANG WeiQing 2 1 State Key Laboratory of Geomechanics and Geotechnical engineering,Institute of Rock and Soil Mechanics, Chinese Academy of Sciences,Wuhan 430071,china 2school of Civil engineering,southwest jiaotong university,chengdu 610031,china State Key Laboratory of Geomechanics and Geotechnical engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences school of Civil engineering Southwest Jiaotong University

One kind of 3D coupled thermo-hydro-mechanical-migratory model for saturated-unsaturated dual-porosity medium was established,in which the stress field and the temperature field are single,but the seepage field and the concentration field are double,and the influences of sets,spaces,angles,continuity ratios,stiffness of fractures on the constitutive relationship of the medium can be *** relative three-dimensional program of finite element method was also *** comparing with the existing computation example,reliability of the model and the program were *** a hypothetical nuclear waste repository as a calculation example,the radioactive nuclide leak was simulated numerically with both the rock mass and the buffer being unsaturated media,and the temperatures,negative pore pressures,flow velocities,nuclide concentrations and normal stresses in the rock mass were *** results showed that the temperatures,negative pore pressures and nuclide concentrations in the buffer all present nonlinear changes and distributions that even though the saturation degree in porosity is only about 1/9 of that in fracture,the flow velocity of underground water in fracture is about 6 times of that in porosity because the permeability coefficient of fracture is almost four orders higher than that of porosity,and that the regions of stress concentration occur at the vicinity of two sides of the boundary between buffer and disposal pit wall.

关键词： dual-porosity medium thermo-hydro-mechanical-migratory coupling three-dimensional model FEM analysis

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Characteristic　Properties　of　Perspective　Sets　for　Finite　Stochastic　Decision

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Journal of Systems engineering and Electronics 1998年第3期9卷 8-15页

作者： Zhang Mingshan & Guo Yaohuang (College of Econonlics and Management, southwest jiaotong university, chengdu 610031, P. R. china ) College of Economics and Management Southwest Jiaotong University Chengdu 610031 P. H. China

For a perspective set that is derived by finite consequences with probabilities, this paper introduces the conception of basis that is proved and the uniqueness of basis over a perspective set holds. These give the characteristic properties of perspective sets and finite consequences with probabilities. These properties are applied to the utility defined by the consequences.

关键词： Perspective set Basis Characteristic properties Utility functions

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THE STRAIN CYCLIC CHARACTERISTICS AND RATCHETING OF U71Mn RAIL STEEL UNDER UNIAXIAL LOADING

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Acta Metallurgica Sinica(English Letters) 2000年第3期13卷 893-900页

作者： G.Z. Kang Q. Gao, X.J.Yang and Y.F. Sun(Department of Applied Mechanics and engineering, southwest jiaotong university, chengdu 610031, china) southwest jiaotong Univ Chengdu China

An experimental study was carried out of the cyclic behavior of U71Mn rail steel subjected to uniaxial strain and stress. The effects of cyclic struin amplitude, mean struin,strain loading rate and their histories on the strain cyclic characteristics were *** the asymmetrical stress cycling, the effects of stress amplitude, mean stress,stress loading rate and their histories on the ratcheting were analyzed. The interaction between strain cycling and stress cycling was also discussed. It is shown that either the cyclic characteristics under strain cycling or the ratcheting under asymmetrical stress cycling depends not only on the cumnt loading state, but also on the previous loading history. Some significant results are obtained.

关键词： cyclic plasticity ratcheting U71Mn rail steel uniaxial loading

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The New Method for CNC Trajectory Machining Motion Planning Based on Reference Time

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武汉理工大学学报 2006年第S2期28卷 659-663页

作者： JIANG Yongmin~1 XU Mingheng~2 1.Department of Mechanical engineering,school of southwest jiaotong university,chengdu 610031,china, Department of Mechanical engineering School of Southwest Jiaotong UniversityChengdu 610031China

In order to make motion planning fitting practice,many characteristic of CNC trajectory motion are discussed, such as the geometric function,the motion and the *** is found that the relation between orbit function and motional parame- ter,so the differential equation about the trajectory motion be set-up by the goal of trajectory *** actual motion process is defined as reference time to link planning and *** a new movement planning method based on self-defining *** rest state,the differential simultaneous equation can be calculated according geometric characteristic analysis,it can be get that simple function consisted of coordinate and reference time *** motive state,dynamic parameter can be worked out accord- ing practical value of reference time,It is proved by experiment and simulation that it is a good way to control geometry and motion comprehensively,to reduce computation times and to increase the ability of environmental adaptation for path

关键词： reference time motion planning trajectory simultaneous equation hyperspace

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Stability Robustness Measures of Linear Discrete-Time Systems with Structured Perturbations

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Systems Science and Systems engineering 1999年第1期9卷 58-64页

作者： CAO Dengqing(Institute of APPlied Mechanics, southwest jiaotong university, chengdu 610031, china)

This paper consider the robust stability of linear discrete-time systems subjected toreal structured perturbations. The "zero exclusion principle", which is based on the properties of theKronecker product and the bialternate product, is employed to derive the new robust stability boundsfor time-invariant perturbations. A numerical examples is Presented to demonstrate the merit of theproposed method. The example shows that the new bounds are easy to compute numerically and canhave an arbitrary degree of improvement over the Previous ones reported by the Lyapunov stabilitymethod.

关键词： robust stability linear discrete-time systems structured perturbations matrix approach

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基于变电所自动化系统的互感器断线检测

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铁道学报 2002年第2期24卷 39-43页

作者：高仕斌西南交通大学电气工程学院四川成都610031

牵引变电所电压、电流互感器时常发生断线故障 ,直接影响继电保护的正确动作和测量表计的正常指示 ,危及牵引供电系统的安全运行。由于牵引供电系统的特殊性 ,电力系统相对成熟的检测方法在牵引供电系统可能不适用 ,本文基于牵引变电所... 详细信息

牵引变电所电压、电流互感器时常发生断线故障 ,直接影响继电保护的正确动作和测量表计的正常指示 ,危及牵引供电系统的安全运行。由于牵引供电系统的特殊性 ,电力系统相对成熟的检测方法在牵引供电系统可能不适用 ,本文基于牵引变电所综合自动化系统的硬件平台和冗余信息 ,提出了在变电所监控主机或调度端实现的电压。

关键词：电压互感器电流互感器断线故障牵引变电所综合自动化系统检测

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ON NONPROPORTIONAL CYCLIC PLASTIC BEHAVIOR OF STEEL 40

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Acta Mechanica Solida Sinica 1995年第1期8卷 84-93页

作者： Cai Lixun Yang Xianjie, southwest jiaotong university, chengdu 610031, P. R. china southwest Jiaptomg university Chengdu 610031 P. R. China

An experimental investigation was carried out on the flow characteristic and hardening of steel 40 subjected to complex combined axial-torsional cyclic straining. For a specific cyclic strain path, the steel has mainly cyclic softening behavior when the strain amplitude is small. While with an increase of the effective strain amplitude, the softening becomes small, but there is the cyclic softening even though the steel is subjected to the cyclic loading by a square strain path. However, the steel has cyclic additional hardening by a nonproportional path, compared with the proportional cycling. Generally, the additional hardening is small and its historical effect is not obvious at small strain amplitude. The additional hardening is remarkable by a cross-triangular strain path of large strain amplitude. The memory of the history of nonproportional cyclic loading, the direction of plastic flow and the plastic modulus of the steel were also studied.

关键词： steel 40 nonproportional cyclic loading plastic flow hardening softening

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Analysis on Dam-Breaking Mode of Tangjiashan Barrier Dam in Beichuan County

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Journal of Mountain Science 2011年第2期8卷 354-362页

作者： HU Xiewen LUO Gang LV Xiaoping HUANG Runqiu SHI Yubin Faculty of Geosciences and Environmental engineering Southwest Jiaotong University Chengdu 610031 China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 China Aseismic engineering Technology Key Laboratory of Sichuan Province Southwest Jiaotong UniversityChengdu 610031 China chengdu Hydroelectric Investigation and Design Institute China Hydropower Consulting Group Chengdu 610072 China

Tangjiashan landslide is a typical high-speed consequent landslide of medium-steep dip angle. This landslide triggered by earthquake took place in about semi-minute. The relative sliding displacement is 900 meters, so average sliding speed is about 30 meters per second. The longitudinal length of barrier dam which is formed by high-speed landslide along river is 803.4 meters; and maximum width crossing river is 611.8 meters. And its volume is estimated about 20.37 million steres. Through detailed geological investigation of the barrier dam, together with early geological information before earthquake, geological structures of the barrier dam and its stability of upstream and downstream slopes are studied when water level reaches different elevations in condition of continual after shocks with seismic intensity of 7 or 8 Richter scale. On this basis, dam-breaking mode of barrier dam is discussed deeply. Thereby, analytic results provide significant guidance and advices to front headquarters of Tangjiashan barrier dam, so that some proper engineering measures can be implemented and flood discharge can be carried out well.

关键词： Tangjiashan Barrier Dam High-speed landslide Blocking river Dam-breaking

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Frequency Response Design Method for PDFSV Control of Electrohydraulic Servo Systems

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Journal of Modern Transportation 1997年第1期14卷 63-69页

作者： Xu Mingheng school of Mechanical engineering, southwest jiaotong university, chengdu 610031, china

The frequency response design method for PDFSV (Pseudo Derivative Feedback Subvariable) control of electrohydraulic servo system is introduced. Theoretical analysis and computer simulation show that PDFSV control is a high robust system, and a very good performance can be obtained when this theory is employed in electrohydraulic servo system.

关键词： PDFSV control frequency response design electrohydraulic servo system

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