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Continuum damage mechanics based modeling progressive failure of woven-fabric composite laminate under low velocity impact

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第3期11卷 151-164页

作者： zhi-gang hu Yan ZHANG State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Arup Shanghai Shanghai 200031China

A continuum damage mechanics (CDM) meso-model was derived for both intraply and interply progressive failure behaviors of a 2D woven-fabric composite laminate under a transversely low velocity *** in-plane anisotropic damage constitutive model of a 2D woven composite ply was derived based on CDM within a thermodynamic framework,an elastic constitutive model with damage for the fibre directions and an elastic-plastic constitutive model with damage for the shear *** progressive failure behavior of a 2D woven composite ply is determined by the damage internal variables in different directions with appropriate damage evolution *** interface between two adjacent 2D woven composite plies with different ply orientations was modeled by a traction-separation law based interface *** isotropic damage constitutive law with CDM properties was used for the interface element,and a damage surface which combines stress and fracture mechanics failure criteria was employed to derive the damage initiation and evolution for the mixed-mode delamination of the interface *** analysis and experiments were both carried out on a 2D woven glass fibre/epoxy *** simulation results are in agreement with the experimental counterparts,verifying the progressive failure model of a woven composite *** proposed model will enhance the understanding of dynamic deformation and progressive failure behavior of composite laminate structures in the low velocity impact process.

关键词： Continuum damage mechanics (CDM) Woven composite laminate Low velocity impact Interface element Cohesive zone

Tetraethylenepentamine-functionalized magnetic mesoporous composites as a novel adsorbent for the removal Cr(Ⅲ)-ethylenediaminetetraacetic acid in complex solution

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Chinese Journal of Chemical Engineering 2024年第4期68卷 16-26页

作者： zhi hu Jiahong Wang Tongtong Sun School of Environmental Science and Engineering Shaanxi University of Science&TechnologyXi'an 710021China Shaanxi Key Laboratory of Green Preparation and Functionalization of Inorganic Materials Xi'an 710021China

A novel tetraethylenepentamine(TEPA) functionalized magnetic mesoporous silica adsorbent(FNMs/TEPA) was prepared for the adsorption of Cr(Ⅲ)-ethylenediaminetetraacetic acid(EDTA)from wastewater. The characterization of the prepared adsorbent certified that TEPA was modified onto the magnetic mesoporous silicon(FNMs), while FNMs/TEPA maintained the ordered mesoporous and pristine magnetic properties. The batch adsorption experiments demonstrated that TEPA significantly enhanced the removal capacity of the adsorbent for Cr(Ⅲ)-EDTA. FNMs/TEPA exhibited an excellent adsorption property(13.84 mg·g-1) at p H 4.0. Even in the presence of high concentrations of coexisting ions and organic acids, the adsorption performance of FNMs/TEPA was stable. Experimental characterization and DFT demonstrated that the adsorption of Cr(Ⅲ)-EDTA was ascribed to the electrostatic interaction, hydrogen bonding, and complexation between Cr(Ⅲ)-EDTA and amino groups on the adsorbent surface. The analysis of the independent gradient model(IGM) shows that electrostatic interaction is the main mode of action in the adsorption process. Moreover, FNMs/TEPA demonstrated remarkable reusability in three regeneration cycles. These findings indicated that FNMs/TEPA possessed excellent application prospects in the disposal of wastewater containing Cr(Ⅲ)-EDTA.

关键词： TEPA functionalized magnetic mesoporous silicon Adsorption Cr(III)-EDTA Density functional theory calculations

Elliptic curve with Optimal mixed Montgomery-Edwards model for low-end devices

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Science China(Information Sciences) 2015年第11期58卷 67-74页

作者： LIU Zhe hu zhi WU Wei University of Luxembourg School of Mathematics and Statistics Central South University School of Mathematics and Computer Science Fujian Normal University

This paper introduces a special family of twisted Edwards curve named Optimal mixed MontgomeryEdwards(OME) curves. The OME curve is proposed by exploiting the fact that every twisted Edwards curve is birationally equivalent to some elliptic curve in Montgomery form. The OME curves achieve optimal group arithmetic for both of twisted Edwards model and Montgomery model. In particular, the Montgomery model of OME curves only requires 3M + 2S and 1M + 3S + 3C to perform the point addition and point doubling operations, while 7M and 3M + 4S are needed for executing a point addition and point doubling for the twisted Edwards model of them. We also make effort to carefully choose the curve parameters and the underlying implementation field to achieve high performance. An example of OME curve is E /Fp:-x2+y2= 1-27822·x2y2over p = 2192- 264- 1. Our implementation results on the widely used 8-bit micro-controller platforms(i.e.,AVR Atmega128) further demonstrate and highlight the practical benefits of proposed OME curve on low-end device. In particular, our implementation, performed in constant-time, reduces the execution time by up to14% and 18% for fixed point and random point scalar multiplication, respectively, when comparing with the state-of-the-art implementation on the identical platform.

关键词： cryptography elliptic curve scalar multiplication efficient implementation 8-bit AVR processors

Simple method to rapidly fabricate chain-like carbon nanotube films and its field emission properties

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International Journal of Minerals,Metallurgy and Materials 2010年第3期17卷 371-375页

作者： zhi-yuan Wu Shuang-qi hu zhi-qian Wang Chemical Industry and Ecology Institute North University of China Taiyuan 030051 China

A simple process to fabricate chain-like carbon nanotube （CNT） films by microwave plasma-enhanced chemical vapor deposition （MPCVD） was developed successfully. Prior to deposition, the Ti/Al2O3 substrates were ground with Fe-doped SiO2 powder. The nano-structure of the deposited films was analyzed by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and Raman spectroscopy. The field electron emission characteristics of the chain-like carbon nanotube films were measured under the vacuum of 10-5 Pa. The low turn-on field of 0.80 V/μm and the emission current density of 8.5 mA/cm2 at the electric field of 3.0 V/μm are obtained. Based on the above results, chain-like carbon nanotube films probably have important applications in cold cathode materials and electrode materials.

关键词： carbon nanotube (CNT) chain-like film microwave plasma-enhanced chemical vapor deposition (MPCVD) field emission

Precise Asymptotics for Lévy Processes

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Acta Mathematica Sinica,English Series 2007年第7期23卷 1265-1270页

作者： zhi Shui hu Chun SU Department of Statistics and Finance University of Science and Technology of China

Let {X（t）, t ≥ 0} be a Lévy process with EX（1） = 0 and EX^2（1）〈 ∞. In this paper, we shall give two precise asymptotic theorems for {X（t）, t 〉 0}. By the way, we prove the corresponding conclusions for s... 详细信息

关键词： precise asymptotic Lévy process stable process Fuk-Nagaev type inequality

The compound Poisson risk model with dependence under a multi-layer dividend strategy

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Applied Mathematics(A Journal of Chinese Universities) 2011年第1期26卷 1-13页

作者： ZHANG zhi-min YANG hu Department of Statistics and Actuarial Science Chongqing University Chongqing 401331 China

In this paper, a compound Poisson risk model with time-dependent claims is studiedunder a multi-layer dividend strategy. A piecewise integro-differential equation for the Gerber- Shiu function is derived and solved. A... 详细信息

关键词： Multi-layer dividend strategy integro-differential equation Cerber-Shiu discounted penalty function heavy-tailed distribution.

Proof of Ding’s Conjecture on Maximal Stable Sets and Maximal Cliques in Planar Graphs

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Acta Mathematicae Applicatae Sinica 2010年第3期26卷 473-480页

作者： Jing Sun zhi-quan hu Faculty of Mathematics and Statistics Central China Normal University Wuhan 430079 China School of Mathematics and Quantitative Economics Hubei University of Education Wuhan 430205 China

X. Deng et al. proved Chvātal＇s conjecture on maximal stable sets and maximal cliques in graphs. G. Ding made a conjecture to generalize Chvátal＇s conjecture. The purpose of this paper is to prove this conjecture ... 详细信息

关键词： Maximal stable set maximal clique planar graph

Hairy Root and Its Application in Plant Genetic Engineering

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Journal of Integrative Plant Biology 2006年第2期48卷 121-127页

作者： zhi-Bi hu Min Du Institute of Chinese Materia Medica Shanghai University of Traditional Chinese Medicine Shanghai 201203 China

Agrobacterium rhizogenes Conn. causes hairy root disease In plants. Hairy root-Infected A. rhizogenes Is characterlzed by a high growth rate and genetic stability. Hairy root cultures have been proven to be an efficient means of producing secondary metabolites that are normally biosyntheslzed In roots of differentiated plants. Furthermore, a transgenlc root system offers tremendous potential for introducing additional genes along with the RI plasmld, especially with modified genes, into medicinal plant cells with A. rhizogenes vector systems. The cultures have turned out to be a valuable tool with which to study the biochemical properties and the gene expression profile of metabolic pathways. Moreover, the cultures can be used to elucidate the Intermediates and key enzymes Involved In the biosynthesis of secondary metabolites. The present article discusses various appllcations of hairy root cultures in plant genetic engineering and potential problems aseoclsted with them.

关键词： Agrobacterium rhizogenes hairy root plant genetic engineering Ri plasmid secondary metabolites.

Semi-gas kinetics model for performance modeling of flowing chemical oxygen-iodine lasers(COIL)

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Science China(Physics,Mechanics & Astronomy) 2004年第3期47卷 338-351页

作者： GAO zhi hu Limin SHEN Yiqing Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

A semi-gas kinetics (SGK) model for performance analyses of flowing chemical oxygen-iodine laser (COIL) is presented. In this model, the oxygen-iodine reaction gas flow is treated as a continuous medium, and the effect of thermal motions of particles of different laser energy levels on the performances of the COIL is included and the velocity distribution function equations are solved by using the double-parameter perturbational method. For a premixed flow, effects of different chemical reaction systems, different gain saturation models and temperature, pressure, yield of excited oxygen, iodine concentration and frequency-shift on the performances of the COIL are computed, and the calculated output power agrees well with the experimental data. The results indicate that the power extraction of the SGK model considering 21 reactions is close to those when only the reversible pumping reaction is considered, while different gain saturation models and adjustable parameters greatly affect the output power, the optimal threshold gain range, and the length of power extraction.

关键词： chemical oxygen-iodine laser (COIL), semi-gas kinetics (SGK) model, rate equation (RE) model, homogeneous broadening, inhomogeneous broadening, performance analysis, spectral line broadening (SLB) model.