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Electron Beam Curing of Advanced Composites

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Journal of Materials Science & Technology 2000年第6期16卷 627-630页

作者： Sui, g. Zhong, W.H. zhang, Z.g. Dep. of Materials Sci. and Eng. Beijing Univ. of Aeron. and Astron. Beijing 100083 China

The fundamental concept of electron beam method and the application in cure of composites are elaborated in this paper. The components of electron beam curing system are introduced. The mechanisms of interaction between electron beam and polymer matrix composites are presented. Recent studies including work of authors themselves on electron beam curing of composites are also discussed. Moreover, the authors believe that it is necessary to do the basic research about understanding how electron beam affects cured network and the mechanical/physical properties of the composites for establishing a quantitative or semi-quantitative formulation.

关键词： Electron Beam Curing of Advanced Composites EB

Corrosion behavior of 13Cr stainless steel under stress and crevice in high pressure CO_(2)/O_(2)environment

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Journal of Materials Science & Technology 2021年第29期88卷 79-89页

作者： g.Y.Zhu Y.Y.Li B.S.Hou Q.H.zhang g.A.zhang Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Materials Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China

In this work,through the self-developed setup for in situ electrochemical tests,the corrosion behavior of 13 Cr stainless steel under the combined effect of stress and crevice in high pressure CO_(2)/O_(2)environment was *** results show that 13 Cr stainless steel presents a self-passivation *** the action of stress,the anodic dissolution process of steel inside crevice is *** is a galvanic effect between the stressed steel inside crevice and the unstressed steel outside *** applied stress reduces the induction stage of crevice corrosion and induces a larger galvanic current,i.e.,the applied stress promotes the development of crevice ***,adding 0.1 MPa O_(2)is conducive to forming a more stable passive film but causes a greater galvanic effect.

关键词： Stainless steel Crevice corrosion Stress corrosion galvanic effect

Simulation of multi-scale heterogeneity of porous media and parameter sensitivity analysis

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Science China(Technological Sciences) 2003年第5期46卷 459-474页

作者： zhang Yong (张勇) g.E. Fogg Hydrologic Science University of California Davis CA 95616-8627 USA Hydrologic Science University of California Davis CA 95616-8627 USA

Because of the inherent multi-scale heterogeneity of porous media and the limitation of single-subject observed data, we propose to combine deterministic and stochastic techniques to simulate heterogeneity. We select a coastal plain sediment system as an example to demonstrate and verify this approach. Firstly, we apply transition probability matrix to determine and delineate the nonstationary unconformity, and combine hydro-stratigraphy analyses to establish the field/large-scale, deterministic stratigraphy model. Secondly, we apply fence diagrams and CPT data to infer the horizontal mean length of hydrofacies, and then build Markov chain models for each depositional system and simulate the local/intermediate-scale, stochastic hydrofacies model. Finally, we combine the stratigraphy and hydrofacies models to get a multi-scale heterogeneous model embedded with quantitative and qualitative observed data, with both deterministic and stochastic characteristics. In order to study the influence of uncertainty in model parameters on solute transport, we build multiple realizations of two types of heterogeneous model and use them to simulate groundwater flow and solute transport. The parameter sensitivity analysis shows the 1st and 2nd spatial moments of the contaminant plume increase with the lateral average length of hydrofacies.

关键词： heterogeneity, scale, Markov-chain, mean-length.

Bound lipids in lacustrine sediments in guchenghu Lake, East China

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Chinese Science Bulletin 1997年第21期42卷 1817-1820页

作者： zhang, g Sheng, gY Fu, JA Chinese Acad Sci Guangzhou Inst Geochem Guangzhou 510640 Peoples R China

BIOMARKERS used as indicators of the paleoclimatic and paleoenvironmental changes are re-quired to be bio-specific in origin and be stable in the early diagenesis process. The input ofplenty of land-derived organics, as well as possible changes in the early diagenesis process,made the lipid composition of inland lacustrine sediments more complicated, and, as a result,the bio-indicating significance of some biomarkers often become obscured. Except for

关键词： bound lipids composition sources paleoenvironmental changes.

A node-based smoothed point interpolation method for dynamic analysis of rotating flexible beams

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Acta Mechanica Sinica 2018年第2期34卷 409-420页

作者： C.F.Du D.g.zhang L.Li g.R.Liu College of Civil Science and Engineering Yangzhou University School of Sciences Nanjing University of Science and Technology School of Aerospace Systems University of Cincinnati

We proposed a mesh-free method, the called node-based smoothed point interpolation method(NS-PIM),for dynamic analysis of rotating beams. A gradient smoothing technique is used, and the requirements on the consistence of the displacement functions are further weakened. In static problems, the beams with three types of boundary conditions are analyzed, and the results are compared with the exact solution, which shows the effectiveness of this method and can provide an upper bound solution for the *** means that the NS-PIM makes the system soften. The NS-PIM is then further extended for solving a rigid-flexible coupled system dynamics problem, considering a rotating flexible cantilever beam. In this case, the rotating flexible cantilever beam considers not only the transverse deformations,but also the longitudinal deformations. The rigid-flexible coupled dynamic equations of the system are derived via employing Lagrange’s equations of the second type. Simulation results of the NS-PIM are compared with those obtained using finite element method(FEM) and assumed mode method. It is found that compared with FEM, the NS-PIM has anti-ill solving ability under the same calculation conditions.

关键词： Meshfree method NS-PIM Rigid-flexible coupled system dynamics Rotating beams Dynamic response

Oscillation of Second Order Nonlinear Delay Damped Difference Equations

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Acta Mathematica Sinica,English Series 2007年第4期23卷 715-722页

作者： S.H.SAKER B.g.zhang Department of Mathematics Faculty of ScienceMansoura UniversityMansoura 35516Egypt Department of Mathematics Ocean University of ChinaQingdao 266071P.R.China

Some new oscillation criteria for nonlinear delay difference equation with damping △^2xn＋pn△xn＋F（n,x（n-τ,△x（n-σ）=0,n=0,1,2,…,（＊）are given. Our results partially solve the open problem posed in [Math. Bohemica, 125 （2000）, 421- 430]. Also, we will establish some new oscillation criteria for special cases of （＊）, which improve some of the well-known results in the literature.

关键词： oscillation second-order difference equations Riccati techniques

The Trend of Aging In China

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China Population Today 1997年第6期14卷 11-12页

作者： g zhang

The high-variant projection shows Chind s population will rise from 1.281 bilion in 2000 to 1.666 billion in *** n1m nber of children(aged 0-14)1 will decrease from 336 million in 2000 to311 million in *** the working... 详细信息

关键词： Trend In China The Aging

Energetics of protein backbone hydrogen bonds and their local electrostatic environment

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Science China Chemistry 2014年第12期57卷 1708-1715页

作者： DUAN Li L gAO Ya JI Chang g MEI Ye zhang Qing g TANg Bo zhang John Z.H College of Physics and Electronics Shandong Normal University College of Chemistry Chemical Engineering and Materials Science Collaborative Innovation Center of Functionalized Probes for Chemical Imaging Key Laboratory of Molecular and Nano Probes Ministry of Education Shandong Normal University State Key Laboratory of Precision Spectroscopy Department of Physics Institute of Theoretical and Computational Science East China Normal University NYU-ECNU Center for Computational Chemistry at NYU Shanghai

MD simulation study of several peptides including a polyalanine,a helix(pdb:2I9M),and a leucine zipper were carried out to investigate hydrogen bond energetics using dynamic polarized protein-specific charge(DPPC)to account for the polarization effect in protein *** show that the backbone hydrogen-bond strength is generally correlated with its specific local electrostatic environment,measured by the number of water molecules near the hydrogen bond in the first solvation *** correlation coefficient is found to be 0.89,0.78,and 0.80,respectively,for polyalanine,2I9M protein,and leucine *** the polyalanine,the energies of the backbone hydrogen bonds are very similar to each other due to their similar local electrostatic *** current study helps demonstrate and support the understanding that hydrogen bonds are stronger in a hydrophobic surrounding than in a hydrophilic *** comparison,the result from simulation using standard force field shows a much weaker correlation between hydrogen bond energy and local electrostatic environment due to the lack of polarization effect in the force field.

关键词： dynamic polarized protein-specific charge hydrogen bond polarization hydrophobic hydrophilic lucine zipper MD simulation

The Efficiency Analysis and A Market Decision Model on Equipment Maintenance

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Journal of Systems Engineering and Electronics 2001年第3期12卷 31-38页

作者： zhang, g. Cao, X. Wang, J. College of Economics and Management Guangdong University of Technology Guangzhou 510090 P. R. China

This paper presents and analyses the internal and external efficiencies of equipment maintenance, and presents that the objective of maintenance is the maximum external efficiency. It defines generalized reliability degree of equipment and deduces the correspondent calculating method. It overcomes the defect that traditional calculating method of reliability degree has, which only considers the factor of time not function, therefore we establish a market decision model of equipment maintenance based on it. This model can determine the marginal efficiency of maintenance investment and critical value of generalized reliability degree when it reaches break-even point. After combining the equipment maintenance with economical benefit of enterprise and marketing situation of products, an optimal maintenance strategy will be got. It provides a new method for scientific and rational decisions of equipment maintenance.

关键词： Market decision model Equipment maintenance generalized reliability degree.