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Acta Metallurgica Sinica(English Letters) 1992年第9期5卷 178-182页

作者： QIAO Lijie LIU Rui XIAO Jimei university of science and {2. Beijing,Beijing,china

The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.

关键词： stress corrosion cracking stress compoonent brass ammonia solution

Uniform estimate for maximum of randomly weighted sums with applications to insurance risk theory

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science china Mathematics 2005年第10期48卷 1379-1394页

作者： WANG Dingcheng~1 SU Chun~2.& ZENG Yong~1 1. School of Management and School of Applied Mathematics,university of Electronic science and {2. of china,Chengdu 610054,china 2. department of Statistics and Finance,university of science and technology of china,hefei 2.002.,china School of Management and School of Applied Mathematics University of Electronic Science and Technology of China Chengdu China department of Statistics and Finance University of Science and Technology of China Hefei China

This paper obtains the uniform estimate for maximum of sums of independent and heavy-tailed random variables with nonnegative random weights, which can be arbitrarily dependent of each other. Then the applications to ... 详细信息

关键词： dependent stochastic return, discount factor, heavy-tails, discrete time insurance risk model, maxima of randomly weighted sums, ruin probability, tail probabilities, uniformly asymptotic estimate.

Two-dimensional simulation of Poiseuille-Rayleigh-Bénard flows in binary fluids with Soret effect

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Progress in Natural science:Materials International 2007年第12期17卷 1389-1396页

作者： Hu Jun1 and Yin Xieyuan2.1. Institute of Applied Physics and Computational Mathematics, Beijing 100088, china 2. department of Modern Mechanics, {2., hefei 2.002., china) Institute of Applied Physics and Computational Mathematics Beijing 100088 China department of Modern Mechanics University of Science and Technology of China Hefei 230027 China

Poiseuille-Rayleigh-Bénard flows in binary fluids with Soret effect are directly simulated by a mixed finite element method. A temperature perturbation is used as an initial disturbed source for the basic parallel flows. The whole spatio-temporal evolution of the binary fluid flows is exhibited: initially only the disturbed mode with the wavenumber k=π is amplified while others are damped, and continuously the amplified mode grows further and the nonlinear effect becomes important; after a nonlinear evolution transition the flow system evolves finally into a periodic right traveling wave.

关键词： Poiseuille-Rayleigh-Bénard flow Soret effect through-flow.

Internal noise stochastic resonance in CO oxidation on nm-sized palladium particles

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science china Chemistry 2005年第5期48卷 395-401页

作者： GONG Yubing1,2. HOU Zhonghuai1 & XIN Houwen1 1. department of Chemical Physics, university of science and technology of china, {2., china 2. department of Physics, Yantai Teachers university, Yantai 2.402., china department of Chemical Physics University of Science and Technology of China Hefei China department of Physics Yantai Teachers University Yantai China

Based on a stochastic mesoscopic model, the influence of internal noise on the oscillatory kinetics of the catalytic oxidation of CO on nm-sized palladium particles is studied, using the chemical Langevin equations, Poisson approximation algorithm, and exact stochastic simulation algorithm. The reaction rate oscillations are of stochastic nature due to considerable internal noise in such mesoscopic systems. It is found that the performance of the stochastic oscillations undergoes a maximum with the variation of internal noise level for a given CO partial pressure, which demonstrates the occurrence of internal noise stochastic resonance. This phe-nomenon implies that optimal internal noise would favor the reaction rate oscillation of CO oxi-dation on nm particles. Such a phenomenon is robust to the change of external parameters, such as CO pressures.

关键词： nanometer-sized palladium particles, surface catalytic CO oxidation, internal noise, stochastic resonance, chemical Langevin equation.

Stochastic resonance in surface catalytic oxidation of carbon monoxide induced by colored noise

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science china Chemistry 2004年第2期47卷 106-112页

The dynamical behavior of surface catalytic oxidation reaction of Pt(110)/CO+O2.modulated by colored noise, under the condition of specific temperature, has been investigated when the partial pressure of CO gas is near the supercritical Hopf bifurcation point. By computer simulation the oscillation and stochastic resonance induced by colored noise are observed. The influences of the intensity and correlation time of colored noise on stochastic resonance are discussed. The range of sensitivity of the system to the environmental fluctuation is analyzed.

关键词： colored noise, stochastic resonance, surface catalytic reaction of Pt(110)/CO+O2. supercritical Hopf bifurcation, signal-to-noise ratio (SNR).

Experimental study on fire smoke movement in a multi-floor and multi-room building

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science china(Technological sciences) 2005年第3期48卷 292-304页

作者： ZHONG Maohua 1, 2., LI Peide 2., LIU Tiemin 1 , WEI Xing 1, 2.& LIAO Guangxuan 2.1. National Center of Safety science and technology, State Administration of Work Safety, Beijing 10002., {2. 2. State Key Laboratory of Fire science, university of science and technology of china, hefei 2.002., {2. National Center of Safety science and technology State Administration of Work Safety Beijing China State Key Laboratory of Fire science University of Science and Technology of China Hefei China

Fire smoke movement of multi-floor and multi-room (MFMR) fire was studied at the model test building in State Key Laboratory of Fire science (SKLFS). The ingredient, temperature, air pressure difference and air velocity of smoke were measured and analyzed. Meanwhile, the hazard of smoke ingredient to exposed occupants was analyzed based on the national standard, Occupational Exposure Limit for Hazardous Agents in the Workplace (GBZ2.2.02.. The experimental results showed that the maximum temperature difference in MFMR fire was located along the vertical height from the fire source. With the spreading and diffusion of smoke, the temperature of smoke layer would tend to be no difference. In the fire of woodpile and kerosene, the main smoke ingredients such as SO 2., CO and CO 2.would first exceed human’s average physiological limit, while smoke ingredients such as NO and NO 2.would come behind. Because of the higher fluctuation range and frequency of air pressure difference of smoke in multi-layer building fire, the fire smoke would spread around everywhere of the passageway and made the human evacuation more difficult.

关键词： multi-floor and multi-room,fire experiment,smoke spread,smoke toxicity.

Structure and kinematic analysis of a novel 2.DOF translational parallel robot

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Progress in Natural science:Materials International 2007年第10期17卷 1213-1219页

作者： Chen Tao1, Wu Chao2.and Liu Xinjun2.1. School of Application science and technology, Harbin {2. of science and technology, Harbin 150080, china 2. department of Precision Instruments, Tsinghua {2., Beijing 100084, china) School of Application science and technology Harbin University of Science and Technology Harbin 150080 China department of Precision Instruments Tsinghua University Beijing 100084 China

This paper addresses the analysis of a novel parallel robot with 2.translational degrees of freedom (DOFs). The robot can position a rigid body in a plane with constant orientation. The kinematic structure of the robot is first described in detail. Some kinematic problems, such as the inverse and forward kinematics, velocity, and singularity are then analyzed. The working and assembly modes are discussed. Since it is the most important index to design a robot, the workspace of the robot is studied systematically in this paper. Based on the analysis of reachable workspace and singularity, a kind of workspace concept characterizing the region that the end-effector of the robot can reach in practice is defined. The results of this paper will be very useful for the design and application of the robot.

关键词： parallel robot degree of freedom kinematics workspace.

Characteristic modules of quasi-hereditary algebras with three samples

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Chinese science Bulletin 1997年第6期42卷 450-454页

作者： ZHANG Pu and LIN Yanan1. department of Mathematics, university of science and technology of china, {2., china 2. department of Mathematics, Xiamen university, Xiamen 361005, china department of Mathematics University of Science and Technology of China Hefei China department of Mathematics Xiamen University Xiamen China

CLINE et al. have introduced the concept of quasi-hereditary algebra, which provided a

关键词： tilting module characteristic module quasi-hereditary algebra.

Syntheses of amphiphilic biodegradable copolymers of poly(ethyl ethylene phosphate) and poly(3-hydroxybutyrate) for drug delivery

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science china Chemistry 2009年第7期52卷 961-968页

作者： CHENG Jing1 & WANG Jun2.1 department of Polymer science and Engineering, {2., hefei 2.002., china 2.hefei National Laboratory for Physical sciences at Microscale, School of Life sciences, {2., hefei 2.002., china department of Polymer science and Engineering University of Science and Technology of China Hefei China hefei National Laboratory for Physical sciences at Microscale School of Life Sciences University of Science and Technology of China Hefei China

Biodegradable and amphiphilic triblock copolymers poly(ethyl ethylene phosphate)-poly(3-hydroxybutyrate)-poly(ethyl ethylene phosphate) (PEEP-b-PHB-b-PEEP) have been successfully synthesized through ring-opening polymerization. The structures are confirmed by gel permeation chromatography and NMR analyses. Crystallization investigated by X-ray diffraction reveals that the block copolymer with higher content of poly(ethyl ethylene phosphate) (PEEP) is more amorphous, showing decreased crystallizability. The obtained copolymers self-assemble into biodegradable nanoparticles with a coreshell micellar structure in aqueous solution, verified by the probe-based fluorescence measurements and transmission electronic microscopy (TEM) observation. The hydrophobic poly(3-hydroxybutyrate) (PHB) block serves as the core of the micelles and the micelles are stabilized by the hydrophilic PEEP block. The size and size distribution are related to the compositions of the copolymers. Paclitaxel (PTX) has been encapsulated into the micelles as a model drug and a sustained drug release from the micelles is observed. MTT assay also demonstrates that the block copolymers are biocompatible, rendering these copolymers attractive for drug delivery.

关键词： poly(3-hydroxybutyrate) polyphosphoester drug delivery polymeric nanoparticles

γ-Radiation synthesis of nanocrystalline nickel powder from nickel (Ⅱ ) -ammonia complex solution

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Chinese science Bulletin 1997年第8期42卷 644-648页

作者： ZHU Yingjie, QIAN Yitai and ZHANG Manwei1. department of Applied Chemistry, university of science and technology of china, {2., china 2. Structure Research Laboratory, university of science and technology of china, {2., china Departnient of Applied Chemistry University of Scirnce and Technology of China Hefei China Structure Research I.aboratory University of Science and Technology of China Hefei China

NANOCRYSTALLINE nickel is very important for its applications in the fields such as catalysis andmagnetic *** usual method used for preparing nanocrystalline nickel is inert gas e-vaporation,which requires high ***,high temperature easily leads tothe growth or oxidation of nickel *** et *** the nickel microaggre-gates dispersed in solution produced by γ-irradiating a dilute solution of Ni2.

关键词： nickel nanocrystalline powder γ-radiation.