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Damage and progressive failure of concrete structures using non-local peridynamic modeling

Science China(Technological Sciences) 2011年第3期54卷 591-596页

作者： HUANG Dan1,2, ZHANG Qing1,2 & QIAO PiZhong1,3.1 state Key Laboratory of Hydrology-water Resources and Hydraulic Engineering, Hohai university, Nanjing 210098, China 2 department of Engineering Mechanics, Hohai university, Nanjing 210098, China 3.department of Civil and Environmental Engineering, washington state university, pullman, wa 99164-2910, usa 1. state Key Laboratory of Hydrology-water Resources and Hydraulic Engineering Hohai University Nanjing 210098 China2. Department of Engineering Mechanics Hohai University Nanjing 210098 China3. Department of Civil and Environmental Engineering Washington State University Pullman WA 99164-2910 USA

Peridynamics (PD), a recently developed theory of solid mechanics, which employs a non-local model of force interaction and makes use of integral formulation rather than the spatial partial differential equations used in the classical continuum mechanics theory, has shown effectiveness and promise in solving discontinuous problems at both macro and micro scales. In this paper, the peridynamics theory is used to analyze damage and progressive failure of concrete structures. A non-local peridynamic model for a rectangular concrete plate is developed, and a central pairwise force function is introduced to describe the interior interactions between particles within some definite distance. Damage initiation, evolution and crack propagation in the concrete model subject to in-plane uni-axial tension, in-plane uni-axial compression and out-of-plane impact load are investigated respectively. The numerical results show that discontinuities appear and grow spontaneously as part of the solution to the peridynamic equations of motion, and no special failure criteria or re-meshing techniques are required, which proves the potential of peridynamic modeling as a promising technique for analyzing the progressive failure of concrete materials and structures.

关键词： concrete damage progressive failure peridynamic model discontinuities

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The characteristics of CO_2 assimilation of photosynthesis and chlorophyll fluorescence in transgenic PEPC rice

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Chinese Science Bulletin 2001年第13期46卷 1080-1084页

作者： JIAO Demao, LI Xia, HUANG Xueqing, CHI Wei, KUANG Tingyun & Ku SB Maurice1. Institute of Agrobiological Genetics and Physiology, Jiangsu Academy of Agricultural Sciences, Nangjing 210014, China 2. Institute of botany, the Chinese Academy of Sciences, Beijing 100093. China 3. botany department, washington state university,{3., wa 99164.4.36, usa Institute of Agrobiological Genetics and Physiology Jiangsu Academy of Agricultural Sciences Nangjing China Institute of botany The Chinese Academy of Sciences Beijing China botany department Washington State University Pullman USA

With PEPC, PPDK, NADP-ME and PEPC+ PPDK transgenic and untransformed rice (Orysa sativa L.), the activities of related C4 photosynthesis enzymes, the chlorophyll fluorescence parameters, CO2 exchange and other physiological indexes were compared, in which the physiological characteristics of PEPC transgenic rice were mainly studied. The results were as follows: (i) The activities of PEPC in PEPC transgenic rice were 20-fold higher than those in untransformed rice; the light-saturation photosynthetic rates and the carboxylation efficiency of PEPC transgenic rice were increased by 55% and 50% more than those of untransformed rice, respectively, while the CO2 compensation point decreased by 27%. (ii) The PS II photochemical efficiency (Fv/Fm) and photochemical quenching (qp) of transgenic PEPC rice decreased less in comparison with those of untransformed rice after the treatment with high light intensity (3.h) or methyl viologen (MV), a photooxidative reagent, which demonstrated that the tolerance of PEPC

关键词： transgenic rice photosynthetic characteristics photoin-hibition of photosynthesis chlorophyll fluorescence phosphoenopy-ruvate carboxylase (PEPC).

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Science Letters:Radio frequency heating: a potential method for post-harvest pest control in nuts and dry products

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2004年第10期 3-8页

作者： waNG Shao-jin, TANG Ju-ming(department of Biological Systems Engineering, washington state university, pullman, wa 99164-6120,{3.) department of Biological Systems Engineering Washington State University Pullman WA 99164-6120 USA

The multi-billion dollar US tree nut industries rely heavily on methyl bromide fumigation for postharvest insect control and are facing a major challenge with the mandated cessation by 2005 of its use for most applications. There is an urgent need to develop effective and economically viable alternative treatments to replace current phytosanitary and quarantine practices in order to maintain the competitiveness of US agriculture in domestic and international markets. With the reliable heating block system, the thermal death kinetics for fifth-instar codling moth, Indianmeal moth, and navel orangeworm were determined at a heating rate of 18℃/min. A practical process protocol was developed to control the most heat resistant insect pest, fifth-instar navel orangeworm, in in-shell walnuts using a 27 MHz pilot scale radio frequency (RF) system. RF heating to 55℃ and holding in hot air for at least 5 min resulted in 100% mortality of the fifth-instar navel orangeworm. Rancidity, sensory qualities and shell

关键词： Disinfestation Heat Nut Postharvest Radio frequency

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A PARALLEL ITERATIVE DOMAIN DECOMPOSITION ALGORITHM FOR ELLIPTIC PROBLEMS

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Journal of Computational Mathematics 1998年第2期16卷 141-151页

作者： Dao-qi Yang (department of Mathematics, wayne state university, Detroit, MI 48202,{3.) wayne state Univ Dept Math Detroit MI 48202 USA

An iterative nonoverlapping domain decomposition procedure is proposed and analyzed for linear elliptic problems. At the interface of two subdomains, one subdomain problem requires that Dirichlet data be passed to it from the previous iteration level, while the other subdomain problem requires that Neumann data be passed to it. This procedure is suitable for parallel processing. A convergence analysis is established. Standard and mixed finite element methods are employed to give discrete versions of this domain decomposition algorithm. Numerical experiments arc conducted to show the effectiveness of the method.

关键词： Domain decomposition methods finite element methods parallel computing

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Polynomials,Higher Order Sobolev Extension Theorems and Interpolation Inequalities on Weighted Folland-Stein Spaces on Stratified Groups

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Acta Mathematica Sinica,English Series 2000年第3期16卷 405-444页

作者： Guozhen Lu department of Mathematics,wayne state university,Detroit,MI 48202,{3. department of Mathematics Wayne State University Detroit USA

This paper consists of three main *** of them is to develop local and global Sobolev interpolation inequalities of any higher order for the nonisotropic Sobolev spaces on stratified nilpotent Lie *** the extensive research after Jerison’s work[3.on Poincaré-type inequalities for Hrmander’s vector fields over the years,our results given here even in the nonweighted case appear to be *** interpolation inequalities have crucial applications to subelliptic or parabolic PDE’s involving vector *** main tools to prove such inequalities are approximating the Sobolev func- tions by polynomials associated with the left invariant vector fields on *** very useful properties for polynomials associated with the functions are given here and they appear to have independent interests in their own *** the existence of such polynomials is the second main part of this *** results of these two parts have been announced in the author’s paper in Mathematical Research Letters[3.]. The third main part of this paper contains extension theorems on anisotropic Sobolev spaces on stratified groups and their applications to proving Sobolev interpolation inequalities on(εδ)domains. Some results of weighted Sobolev spaces are also given *** construct a linear extension operator which is bounded on different Sobolev spaces *** particular,we are able to construct a bounded linear extension operator such that the derivatives of the extended function can be controlled by the same order of derivatives of the given Sobolev *** are stated and proved for weighted anisotropic Sobolev spaces on stratified groups.

关键词： Poincaré inequalities Extension theorems Interpolation inequalities Anisotropic Sobolev spaces A_p weights (ε,δ)domains Vector fields Polynomials on stratified groups

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Occupation Measures of Singularly Perturbed Markov Chains with Absorbing states

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Acta Mathematica Sinica,English Series 2000年第1期16卷 161-180页

作者： G.Yin~(1)) department of Mathematics,wayne state university,Detroit,MI 48202,{3.Q.Zhang~(2)) department of Mathematics,university of Georgia,Athens,GA 3.602,{3.G.Badowski~(3.) department of Mathematics,wayne state university,Detroit,MI 48202,{3. department of Mathematics Wayne State University Detroit MI 48202 USA department of Mathematics University of Georgia Athens GA 30602 USA

This paper develops asymptotic properties of singularly perturbed Markov chains with inclusion of absorbing *** focuses on both unscaled and scaled occupation *** mild conditions,a mean-square estimate is *** averaging the fast components,we obtain an aggregated *** the aggregated process itself may be non-Markovian,its weak limit is a Markov chain with much smaller state ***,a suitably scaled sequence consisting of a component of scaled occupation measures and a component of the aggregated process is shown to converge to a pair of processes with a switching diffusion component.

关键词： Singularly perturbed Markov chain Occupation measure Aggregation Absorbing state Weak convergence Switching diffusion

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Aggregation and assembly of crescent foldamers

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Science China Chemistry 2010年第1期53卷 45-51页

作者： GONG Bing department of Chemistry,university at Buffalo,The state university of New York,Buffalo,New York 14260,usa 1. department of Chemistry University at Buffalo The State University of New York Buffalo New York 14260 USA

Recent studies have started to provide initial insights into the aggregation and assembly of two classes of back-rigidified foldamers with flat,curved backbones consisting of aromatic *** their persistent shape that presents large,well-defined aromatic surface areas,these crescent foldamers were found to undergo size-dependent aggregation in solution and pack into 1D assemblies in the solid *** aromatic oligoamides undergo stacking interactions not only in polar solvents but also in nonpolar ones,a unique property that is not associated with many other molecules that associate via π-π stacking *** stacking of oligo(m-phenylene ethynylenes) is similar to aromatic hydrocarbons,being promoted in polar solvents such as methanol while being discouraged in nonpolar solvents such as *** ready synthetic availability of crescent foldamers makes it possible to directly control the intermolecular interaction by tuning surface ***,the columnar assembly of these cavity-containing molecules provides a new strategy for constructing supramolecular nanotubular structures.

关键词： foldamer folding hydrogen bond π-π stacking aggregation assembly

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Hormone-based pharmacotherapy for metabolic dysfunction-associated fatty liver disease

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Medical Review 2024年第2期4卷 158-168页

作者： Zara Siu wa Chui Yaqian Xue Aimin Xu state Key Laboratory of Pharmaceutical Biotechnology The University of Hong KongHong Kong SARChina department of Medicine The University of Hong KongHong Kong SARChina School of Biomedical Sciences The University of Hong KongHong Kong SARChina state Key Laboratory of Pharmaceutical Biotechnology The University of Hong Kong999077Hong Kong SARChina department of Medicine The University of Hong Kong999077Hong Kong SARChina department of Pharmacology and Pharmacy The University of Hong Kong999077Hong Kong SARChina

Metabolic dysfunction-associated fatty liver disease(MAFLD)has reached epidemic proportions globally in parallel to the rising prevalence of *** its significant burden,there is no approved pharmacotherapy specifically tailored for this *** potential drug candidates for MAFLD have encountered setbacks in clinical trials,due to safety concerns or/and insufficient therapeutic ***,several investigational drugs that mimic the actions of endogenous metabolic hormones,including thyroid hormone receptorβ(THRβ)agonists,fibroblast growth factor 21(FGF21)analogues,and glucagon-like peptide-1 receptor agonists(GLP-1RAs),showed promising therapeutic efficacy and excellent safety *** them,resmetirom,a liver-targeted THRβ-selective agonist,has met the primary outcomes in alleviation of metabolic dysfunction-associated steatohepatitis(MASH),the advanced form of MAFLD,and liver fibrosis in phase-3.clinical *** hormone-based pharmacotherapies not only exhibit varied degrees of therapeutic efficacy in mitigating hepatic steatosis,inflammation and fibrosis,but also improve metabolic ***more,these three hormonal agonists/analogues act in a complementary manner to exert their pharmacological effects,suggesting their combined therapies may yield synergistic therapeutic *** in-depth studies on the intricate interplay among these metabolic hormones are imperative for the development of more efficacious combination therapies,enabling precision management of MAFLD and its associated comorbidities.

关键词： metabolic hormones metabolic dysfunctionassociated steatohepatitis(MASH) liver fibrosis biopharmaceutical development clinical trials

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Online uniform machine covering with the known largest size

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Progress in Natural Science:Materials International 2007年第11期17卷 1271-1278页

作者： Cao Shunjuan1,2 and Tan Zhiyi1,3.1. department of Mathematics, Zhejiang university, Hangzhou 3.0027, China 2. department of Mathematics, Zhejiang Forestry university, Hangzhou 3.13.0, China 3. state Key Laboratory of CAD & CG, Zhejiang university, Hangzhou 3.0027, China) department of Mathematics Zhejiang University Hangzhou 310027 China department of Mathematics Zhejiang Forestry University Hangzhou 311300 China state Key Laboratory of CAD & CG Zhejiang University Hangzhou 310027 China

This paper investigates the semi-online scheduling problem with the known largest size on two uniform machines. The objective is to maximize the minimum machine completion time. Both lower bounds and algorithms are given. Algorithms are optimal for the majority values of s≥1, where s is the speed ratio of the two machines. The largest gap between the competitive ratio and the lower bound is about 0.064. Moreover, the overall competitive ratio 2 matches the overall lower bound.

关键词： scheduling and covering uniform machine design and analysis of algorithm online competitive ratio

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Surface effects of monolayer-protected gold nanoparticles on the redox reactions between ferricyanide and thiosulfate

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Science China Chemistry 2005年第5期48卷 424-430页

作者： LI Di1, SUN Chunyan1, HUANG Yunjie1, LI Jinghong1,2 & CHEN Shaowei3.1. state Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 13.022, China 2. department of Chemistry, Tsinghua university, Beijing 100084, China 3. department of Chemistry, university of California, Santa Cruz, Santa Cruz, CA 95064, usa 1. state Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences 130022 Changchun China 2. department of Chemistry Tsinghua University 100084 Beijing China 3. department of Chemistry University of California 95064 Santa Cruz Santa Cruz CA USA

Electron transfer through the self-assembled monolayers (SAMs) on gold nanopar-ticles is investigated by using the monolayer protected gold nanoclusters (MPCs) as elec-tron-transfer mediators. 3.Mercaptopropionic acid (MPA) and 11-meraptoundecanoic acid (MUA) MPCs were employed to catalyze the redox reaction between potassium ferricyanide and sodium thiosulfate. The catalytic mechanism was proposed that the MPCs act as diffusing elec-tron-mediators and electron transfers to and from the MPCs surface. Therefore the electron transfer rate through the capping layers would be proportional to the MPCs catalyzed reaction rate, which was monitored by the UV absorbance of ferricyanide. The calculated apparent rate constant was orders of magnitude smaller than that of the maximum of tunneling current, which was attributed to the splited energy level of the nanoscale particles.

关键词： electron transfer, three-dimensional self-assembled monolayers, redox reaction, electron transfer mediator, surface effect.

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