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Modeling on runoff concentration caused by rainfall on hillslopes and application in Maoping slope

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Progress in Natural Science:Materials International 2006年第10期16卷 1056-1065页

作者： LIU Qingquan and LI Jiachun (institute of mechanics, chinese academy of sciences, beijing 100080, china) [a]chinese academy of sciences' Institute of Mechanics' Beijing China

Based on the fact that the concentration flowlines of overland flow depend on the surface landform of hillslope, a kinematic wave model was developed for simulating runoff generation and flow concentration caused by rainfall on hillslopes. The model-simulated results agree well with the experimental observations. Applying the model to the practical case of Maoping slope, we obtained the characteristics of runoff generation and infiltration on the slope. Especially, the simulated results adequately reflected the confluent pattern of surface runoff, which offers a scientific foundation for designing the drainage engineering on the Maoping slope.

关键词： complex hillslope rainfall infiltration overland flow runoff concentration Maoping slope.

An optimization approach to the similarity criteria of flows and its application

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Progress in Natural Science:Materials International 2006年第3期16卷 241-247页

作者： ZHOU Jifu and LI Jiachun (institute of mechanics, chinese academy of sciences, beijing 100080, china) [a]institute of mechanics Chinese Academy of Science Beijing China

In the present paper, we propose an optimization approach to investigate the similarity criteria of complex flows. With this approach, we may identify the dominant dimensionless variables governing complex flows by numerical sensitivity analysis. Firstly, we define the sensitivity factor and examine its dependence on the dimensionless variables. Then, we apply this approach to study the similarity criteria of porous media flow in a presumed oil reservoir. The similarity principle obtained from the numerical sensitivity analysis is in agreement with the theoretical law, thus demonstrating the feasibility of the proposed optimization approach. Further explanation is given by analyzing the deviation of pressure distribution in a model from its prototype. In addition, we examine the effects of flow parameter variation on the sensitivity factors and find that the dominant dimensionless variables may change from different sets of parameters.

关键词： similarity optimization sensitivity analysis complex flows model.

Numerical simulation of Richtmyer-Meshkov instability

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Science china Mathematics 2004年第z1期47卷 234-244页

作者： FU Dexun, MA Yanwen, ZHANG Linbo & TIAN BaolinState Key laboratory of Nonlinear mechanics, institute of mechanics, chinese academy of sciences, beijing 100080, china State Key laboratory of Scientific and Engineering Computing, institute of Computational Mathematics, chinese academy of sciences, beijing 100080, china 1. State Key laboratory of Nonlinear mechanics Institute of Mechanics Chinese Academy of Sciences 100080 Beijing China2. State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics Chinese Academy of Sciences 100080 Beijing China

The compressible Navier-Stokes equations discretized with a fourth order accurate compact finite difference scheme with group velocity control are used to simulate the Richtmyer-Meshkov (R-M) instability problem produced by cylindrical shock-cylindrical material interface with shock Mach number Ms=1.2 and density ratio 1:20 (interior density/outer density). Effect of shock refraction, reflection, interaction of the reflected shock with the material interface, and effect of initial perturbation modes on R-M instability are investigated numerically. It is noted that the shock refraction is a main physical mechanism of the initial phase changing of the material surface. The multiple interactions of the reflected shock from the origin with the interface and the R-M instability near the material interface are the reason for formation of the spike-bubble structures. Different viscosities lead to different spike-bubble structure characteristics. The vortex pairing phenomenon is found in the initial double mode simulation. The mode interaction is the main factor of small structures production near the interface.

关键词： R-M instability, direct numerical simulation, shock-interface interaction.

Quantifying Rosette Formation Mediated by Receptor-ligand Interactions

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生物医学工程学杂志 2005年第S1期22卷 35-36页

作者： Mian LONG(national microgravity laboratory, institute of mechanics, chinese academy of sciences, beijing 100080,china)

Scheme construction with numerical flux residual correction (NFRC) and group velocity control (GVC)

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Progress in Natural Science:Materials International 2006年第12期16卷 1252-1259页

作者： MA Yanwen **and FU Dexun(LNM, institute of mechanics, chinese academy of sciences, beijing 100080, china) [a]LNM Institute of Mechanics Chinese Academy of Sciences Beijing China

For simulating multi-scale complex flow fields like turbulent flows, the high order accurate schemes are preferred. In this paper, a scheme construction with numerical flux residual correction (NFRC) is presented. Any order accurate difference approximation can be obtained with the NFRC. To improve the resolution of the shock, the constructed schemes are modified with group velocity control (GVC) and weighted group velocity control (WGVC). The method of scheme construction is simple, and it is used to solve practical problems.

关键词： high order accurate scheme group velocity control high resolution of the shock.

An SGS Model and Its Application

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Communications in Nonlinear Science and Numerical Simulation 1999年第2期4卷 87-90页

作者： Zhengtong XIE Jiachun LI (institute of mechanics, chinese academy of sciences, beijing 100080, china) institute of mechanics Chinese Academy of Sciences Beijing 100080 China

Based on the turbulent energy and structure function model, a subgridstress model named transitional structure function (TSF) is proposed, which exhibitsmore satisfactory performance than the previous one when applied in turbulent flow withinand above forest *** time and horizontal averaged statistics such as mean verticalprofiles of wind velocity, Reynolds stress, turbulent kinetic energy etc., and instantaneousfields as well are in general agreement with earlier observations, at least in a qualitativesense.

关键词： Large-Eddy simulation SGS model turbulent flow canopy

SYNTHESIS AND CHARACTERIZATION OF NEW STABILIZERS WITH OPTIMAL MOLECULAR WEIGHT

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chinese Journal of Polymer Science 2001年第4期19卷 341-350页

作者： Jiang-qing Pan institute of Chemistry chinese academy of sciences, beijing 100080 china chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

Over 2 x 10(8) tons of polymers are produced every year, and a large portion of polymers faces the degradation problem. There are many effective methods to protect polymers against degradation and the addition of stabilizers to polymer remains the most convenient and effective way of enhancing polymer life and performance. In this article, a series of effective stabilizers with optimal molecular weight (MW), including common, monomeric and polymeric stabilizers (antioxidant and light stabilizer) were synthesized using isocyanation, controlled isocyanation, hydrosilylation, epoxide addition, macroreaction of stabilizing functional compounds and polymerization of monomeric stabilizers. The structure and performance of these new stabilizers were characterized by using IR, NMR, MS, UV-spectra, XPS and elemental analysis. The current development of stabilizer synthesis was also reviewed.

关键词： preparation of stabilizer antioxidant hindered amine light stabilizer isocyanation hydrosilylation

Difference schemes on non-uniform mesh and their application

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Progress in Natural Science:Materials International 2004年第10期14卷 8-14页

作者： MA Yanwen ,GAO Hui,FU Dexun and LI Xinliang (laboratory of Nonlinear mechanics,institute of mechanics,chinese academy of sciences,beijing100080,china) chinese Acad Sci Inst Mech Lab Nonlinear Mech Beijing 100080 Peoples R China

High order accurate schemes are needed to simulate the multi-scale complex flow fields to get fine structures in simula-tion of the complex flows with large gradient of fluid parameters near the wall,and schemes on non-uniform mesh are desirable for many CFD(computational fluid dynamics)*** construction methods of difference approximations and several difference approxima-tions on non-uniform mesh are *** accuracy of the methods and the influence of stretch ratio of the neighbor mesh increment on accuracy are *** comments on these methods are given,and comparison of the accuracy of the results obtained by schemes based on both non-uniform mesh and coordinate transformation is made,and some numerical examples with non-uniform mesh are present-ed.

关键词： scheme on non-uniform mesh high order accurate scheme compact difference approximation

2023 Guideline for the management of hypertension in the elderly population in china

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Journal of Geriatric Cardiology 2024年第6期21卷 589-630页

作者： Hypertension Branch of chinese Geriatrics Society,beijing Hypertension Association,national Clinical Research Center of the Geriatric Diseases Qi HUA Li FAN Zeng-Wu WANG Jing LI 不详 Xuanwu Hospital Capital Medical UniversityBeijingChina chinese PLA General Hospital BeijingChina Fuwai Hospital Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Preamble Hypertension is one of the most common chronic diseases and the primary risk factor for stroke,myocardial infarction and even cardiovascular *** than half of the elderly population has high blood *** people are a unique group,and strategies for the prevention,diagnosis,evaluation,and treatment of hypertension in elderly individuals differ significantly from those in the general population.

关键词： hypertension prevention diagnosis