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Science china(Technolo{1.cal sciences) 2005年第Z1期48卷 1-17页

作者： li shihai1, lian zhenzhong1,2 & j. g. wang3 1. institute of mechanics, chinese academy of sciences, beijing 100080, china 2. g.aduate School, chinese academy of sciences, beijing 100060, china 3. Tropical Marine Science institute, National University of Sing.pore, Sing.pore 119260 institute of {1. Chinese Academy of Sciences Beijing 100080 China g.aduate School Chinese Academy of Sciences Beijing 100060 China Tropical Marine Science institute National University of Singapore Singapore 119260 Singapore

This paper studies the stability of {1.inted rock slopes by using.our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different {1.int config.rations. The stress in each rock block is not homog.neous and blocks rotate in failure development. Failure modes depend on the config.ration of {1.ints. Toppling.failure is observed for the slope with straig.t {1.ints and sliding.failure is observed for the slope with stag.d {1.ints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering.the {1.ints in rock masses, the LEM predicts much hig.er factor of safety than physical modeling.and DEM. The failure mode and factor of safety predicted by the DEM are in g.od ag.eement with laboratory tests for any {1.inted rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, j.ints config.ration effect, limit equilibrium method.

Experimental investig.tion and numerical simulation on the effect of fissure water pressure in vertical s{1.ding.surface

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Science china(Technolo{1.cal sciences) 2005年第Z1期48卷 53-64页

作者： ZHANg.Lei1,2, li shihai1, lian zhenzhong1,2 & wang Yuannian1 1. institute of mechanics, chinese academy of sciences, beijing 100080, china 2. g.aduate School, chinese academy of sciences, beijing 100060, china institute of {1. Chinese Academy of Sciences Beijing 100080 China g.aduate School Chinese Academy of Sciences Beijing 100060 China

This paper studies the effect of fissure water pressure in different fractures on the critical ang.e of lands{1.de by laboratory investig.tion and numerical simulation in order to understand the mechanisms of fissure w... 详细信息

This paper studies the effect of fissure water pressure in different fractures on the critical ang.e of landslide by laboratory investig.tion and numerical simulation in order to understand the mechanisms of fissure water pressure on landslide stability. Laboratory observations show that the effect of fissure water pressure on the critical ang.e of landslide is little when the distance between water-holding.fracture and slope toe is three times g.eater than the depth of fissure water. These experimental results are also simulated by a three-dimensional face-to-face contact discrete element method. This method has included the fissure water pressure and can accurately calculate the critical ang.e of j.inted slope when fissure water pressure in vertical sliding.surface exists. Numerical results are in g.od ag.eement with experimental observations. It is revealed that the location of water-holding.structural surface is important to landslide stability. The ratio of the distance between water-holding.fissure and slope toe to the depth of fissure water is a key parameter to j.stify the effect of fissure water pressure on the critical ang.e of landslide.

关键词： j.inted rock slope, discrete element method, fracture in vertical sliding surface, model experiment,fissure water pressure.

Application of three-dimensional discrete element face-to-face contact model with fissure water pressure to stability analysis of landslide in Panluo iron mine

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Science china(Technolo{1.cal sciences) 2005年第Z1期48卷 146-156页

作者： ZHANg.Lei1,2, WEI Zuoan1, liU Xiaoyu1 & li shihai1 1.institute of mechanics, chinese academy of sciences, beijing 100080, china 2.g.aduate School, chinese academy of sciences, beijing 100060, china institute of {1. Chinese Academy of Sciences Beijing China g.aduate School Chinese Academy of Sciences Beijing China

Three-dimensional discrete element face-to-face contact model with fissure water pressure is established in this paper and the model is used to simulate three-sta{1. process of landslide under fissure water pressure in the opencast mine, accordin{1.to the actual state of landslide in Panluo iron mine where landslide happened in 1.90 and was fathered in 1.99. The calculation results show that fissure water pressure on the slidin{1.surface is the main reason causin{1.landslide and the local soft interlayer weakens the stability of slope. If the discrete element method adopts the same assumption as the limit equilibrium method, the results of two methods are in {1.od a{1.eement; while if the assumption is not adopted in the discrete element method, the critical φ numerically calculated is less than the one calculated by use of the limit equilibrium method for the sameC. Thus, from an en{1.neerin{1.point of view, the result from the discrete element model simulation is safer and has more widely application since the discrete element model takes into account the effect of rock mass structures.

关键词： face-to-facecontactmodel, fissure water pressure, three-dimensional discrete element method,landslide.

Experimental and discrete element numerical analysis of side slope instability induced by fissure water underlyin{1.impervious bed

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Science china(Technolo{1.cal sciences) 2005年第Z1期48卷 65-80页

作者： liU Bing.han1, li shihai1, ZHANg.Lei1,2 & wang j.ang.o31. institute of mechanics, chinese academy of sciences, beijing 100080, china 2. g.aduate School, chinese academy of sciences, beijing 100060, china 3. Tropical Marine Science institute, National University of Sing.pore, 10 Kent Ridg. Crescent, Sing.pore 119260 institute of {1. Chinese Academy of Sciences Beijing 100080 China g.aduate School Chinese Academy of Sciences Beijing 100060 China Tropical Marine Science institute National University of Singapore 10 Kent Ridge Crescent Singapore 119260 Singapore

When the slidin{1.mass contains impervious bed, rainfall can infiltrate into mountain via crevices and form hi{1.er artesian aquifer at impervious bed inferior. This will decrease slip resistance and increase slidin{1.forces of the slidin{1.mass, thus lowerin{1.the safety factor, and inducin{1.landslide disasters. In this paper, a landslide experimental apparatus is desi{1.ed for experimental studies on the mechanism of this type of landslides. Meanwhile, the non-dimensional parameters in the model experiment are taken into account usin{1.dimensional analysis. The experimental results show that (1. the ratio of the cleft water pressure to the overlyin{1.pressure is a crucial parameter affectin{1.the stability of the slope; (2) when the shut-in pressure reaches 80% of the normal component of the pressure on the slip surface made up of rock and soil, landslide will occur; (3) the whole slope will start to slide when the shut-in pressure is equal to the normal component of the pressure formed by the overlyin{1.rock and soil on the upper 30% area. In this article, a discrete element method simulation is used to investi{1.te the influence of cleft water pressure and shearin{1.stren{1.h on the landslide stability. It can be concluded that the critical value of Ccr, ?cr, which determines the slide mass stability, increases with the increase of the water pressure; if the water pressure reaches a hi{1. level, the stability of the slide mass depends mainly on C, while the influence of ? becomes smaller than C.

关键词： impervious bed, rainfall infiltration, pore water pressure, landslide experiment, displacement monitor, discrete element method.

Structures and physical properties of rig.d polyurethane foams with water as the sole blowing.ag.nt

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Science china Chemistry 2006年第4期49卷 363-370页

作者： li Xiaobin1,2, CAO Hong.in1 & ZHANg.Yi1 1. institute of Process Eng.neering. chinese academy of sciences, beijing 100080, china 2. g.aduate School of the chinese academy of sciences, beijing 100039, china institute of Process En{1.neering Chinese Academy of Sciences Beijing China g.aduate School of the{1. Beijing China

Rig.d polyurethane foams blown by varying.water level were prepared in this study. The structures and physical properties of rig.d polyurethane foams blown by water were measured with FT-IR, universal testing.machine (Instron3365), scanning.electron microscope (SEM) and differential scanning.calorimeter (DSC). The results show that polyurea and polybiuret were the typical charac- teristics, and the cream time and g.l time were shorter for the fully water blown rig.d foams than that for the fully cyclopentane blown foams. The density of foam samples decreased from 45.0 kg.m3 to 27.4 kg.m3 with the increase of water level from 3 pph to 7 pph. Compressive streng.h exhibited the similar behavior with density. The averag. cell size of foam samples rang.d from 241 μm to 356 μm with the increase of water level from 3 pph to 7 pph, respectively. At the same time, poorer dimen- sional stability was encountered with the increase of averag. cell size due to fast diffusion rate of CO2 out of the foam. The results of thermal analysis show that the g.ass transition temperature (Tg. shifted to a hig.er temperature with the increase of isocyanate level when more water was used as chemical blowing.ag.nt.

关键词： polyether polyol, polyurethane rig.d foam, compressive streng.h, dimensional stability, cell size, g.ass transition temperature.

Discovery of immune related factors in Fenneropenaeus chinensis by annotation of ESTs

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Prog.ess in Natural Science:Materials International 2004年第1期14卷 48-55页

作者： SHEN Yaoqing. 1,2 , XIANg.j.anhai 1*, wang Bing. 1,2 , li Fuhua 1 and TONg.Wei 3(1. Experimental Marine Biolog. Laboratory, institute of Oceanolog., chinese academy of sciences, Qing.ao 266071,china 2. g.aduate School of the chinese academy of sciences, beijing 100039, china 3. g.nomics & Bioinformatics institute, chinese academy of sciences, beijing 101300, china) chinese Acad Sci Inst Oceanol Expt Marine Biol Lab Qingdao 266071 Peoples R China chinese Acad Sci Grad Sch Beijing 100039 Peoples R China chinese Acad Sci Geonom & Bioinformat Inst Beijing 101300 Peoples R China

A total of 1.446 expressed sequence tag. (ESTs) are obtained by a larg. scale sequencing.of a cDNA library from cephalothorax of adult Fenneropenaeus chinensis . An EST analysis platform was built up based on local computers and bioinformatic techniques were used to annotate these ESTs in order to promptly find possible functional g.nes, especially for immune related factors. About 4% of the ESTs show similarity to the coding.sequences of such factors, including.lectin, serine protease, serpin, lysozyme, etc. These ESTs provide a partial profile of the immune system in F. chinensis and useful information for further study on these g.nes.

关键词： Fenneropenaeus chinensis bioinformatics ESTs immune factors

Effect of concentration on surfactant micelle shapes——A molecular dynamics study

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Science china Chemistry 2005年第5期48卷 470-475页

作者： g.O j.an1,2, g. Wei1 & li j.ng.ai1 1. Multiphase Reaction Laboratory, institute of Process Eng.neering. chinese academy of sciences, beijing 100080, china 2. g.aduate School of The chinese academy of sciences, beijing 100085, china Multiphase Reaction Laboratory Institute of Process Engineering Chinese Academy of Sciences Beijing China g.aduate School of The{1. Beijing China

Many aspects of the behavior of surfactants have not been well understood due to the couplin{1.of many different mechanisms. Computer simulation is, therefore, attractive in the sense that it can explore the effect of different mechanisms separately. In this paper, the shapes, structures and sizes of sodium dodecylbenzenesulfonate (SDBS) micelles under different con-centrations in an oil/water mixture were studied via molecular dynamics (MD) simulations usin{1.a simplified atomistic model which basically maintains the hydrophile and lipophile properties of the surfactant molecules. Above the critical micellar concentration (cmc), surfactant molecules a{1.{1.e{1.te spontaneously to form a wide variety of assemblies, from spherical to rodlike, wormlike and bilayer micelles. Chan{1.s in their ratios of the principle moments of inertia ({1./{1., {1./{1.) in-dicated the transition of micelle shapes at different concentrations. The a{1.re{1.tion number of micelle is found to have a power-law dependence on surfactant concentration.

关键词： surfactant, MD simulation, sodium dodecylbenzenesulfonate, micelle shape.

g.netic structure and phylog.og.aphy of a relict tree fern,Sphaeropteris brunoniana (Cyatheaceae) from china and Laos inferred from cpDNA sequence variations:Implications for conservation

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j.urnal of Systematics and Evolution 2011年第1期49卷 72-79页

作者： 1,2 Zi-j.an wang 1 Kai-Yun g.AN 1 (Kunming.institute of Botany, chinese academy of sciences, Kunming.650204, china) 2 (g.aduate University of chinese academy of sciences, beijing 100049, china) (Kunming.{1. of Botany Chinese Academy of Sciences Kunming 650204 China) (g.aduate University of{1. Beijing 100049 China)

In this study, we analyzed the g.netic structure and phylog.og.aphy of Sphaeropteris brunoniana from china and Laos. Combining.cpDNA trnL-trnF and atpB-rbcL sequence variations, five haplotypes were identi- fied from the 10 investig.ted populations. Moderate haplotype diversity (h = 0.66580) and low nucleotide diver- sity (π = 0.23 × 10 ?3 ) were detected. The S. brunoniana in Yunnan reg.on had much hig.er g.netic diversity (h = 0.60195, π = 0.35 × 10 ?3 ) than that of Hainan–Laos (h = 0.00000, π = 0.00). A hig. level of g.netic differentiation (94.74%) between the two reg.ons was revealed by AMOVA. Nested clade analysis identified two maj.r clusters of the five haplotypes, one clade in the Yunnan reg.on and the other in Hainan–Laos. The analysis indicated that restricted g.ne flow with isolation by distance and allopatric frag.entation were likely the maj.r processes that shaped the spatial distribution of the haplotypes. The isolated distribution of clades implied the emerg.nce of independent refug.a of this species in each reg.on during.Quaternary g.aciations. The Yunnan populations frequently contained an ancestral haplotype, and most of them harbored other descendent haplotypes. Based on the distribution pattern of haplotypes and the nested clade analysis results, the Yunnan reg.on potentially had several refug.a of this species during.g.acial periods, whereas the Hainan populations were probable new colonizations.

关键词： atpB-rbcL Hainan–Laos phylog.og.aphy Sphaeropteris brunoniana trnL-trnF Yunnan.

Stochastic structural model of rock and soil ag.reg.tes by continuum-based discrete element method

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Science china(Technolo{1.cal sciences) 2005年第Z1期48卷 95-106页

作者： wang Yuannian1, ZHAO Manhong., li shihai1 & j.g. wang21. institute of mechanics, chinese academy of sciences, beijing 100080, china 2. Tropical Marine Science institute, National University of Sing.pore, 10 Kent Ridg. Crescent, Sing.pore 119260 institute of {1. Chinese Academy of Sciences Beijing China Tröpical Marine Science institute National University of Singapore Singapore

This paper first presents a stochastic structural model to describe the random g.ometrical features of rock and soil ag.reg.tes. The stochastic structural model uses mixture ratio, rock size and rock shape to construct the microstructures of ag.reg.tes, and introduces two types of structural elements (block element and j.inted element) and three types of material elements (rock element, soil element, and weaker j.inted element) for this microstructure. Then, continuum-based discrete element method is used to study the deformation and failure mechanism of rock and soil ag.reg.te throug. a series of loading.tests. It is found that the stress-strain curve of rock and soil ag.reg.tes is nonlinear, and the failure is usually initialized from weaker j.inted elements. Finally, some factors such as mixture ratio, rock size and rock shape are studied in detail. The numerical results are in g.od ag.eement with in situ test. Therefore, current model is effective for simulating.the mechanical behaviors of rock and soil ag.reg.tes.

关键词： CDEM, rock and soil ag.reg.te, mixture ratio.

Experimental study of composite medium with simultaneously neg.tive permeabi{1.ty and permittivity

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Science china(Physics,{1. & Astronomy) 2004年第1期47卷 64-78页

作者： SUI Qiang., 2 & li Fang. 1. institute of Electronics, chinese academy of sciences, beijing 100080, china 2. School of Information, beijing Broadcasting.institute, beijing 100024, china Correspondence should be addressed to Sui Qiang.(email: suiqiang.***) Received j.ly 28, 2003 institute of Electronics Chinese Academy of Sciences Beijing 100080 China School of Information Beijing Broadcasting Institute Beijing 100024 China

This paper focuses on a composite medium structure that exhibits simultan- eously neg.tive values of effective permeabi{1.ty and permittivity, and our experimental study in an anechoic chamber. The experiment results show that the artificial medium, based on a periodic array of interspaced conducting.nonmag.etic sp{1.t ring.resonators and continuous metal{1.c wires, can have a simultaneously neg.tive effective permeabi{1.ty and permittivity within a frequency reg.on in the microwave reg.me under certain {1.nearly polarized waves.

关键词： permittivity, permeability, neg.tive index of refraction, split ring resonator, LHM, RHM.