检索结果-南通市图书馆

Science china(Technolo{1.cal Sciences) 2005年第z1期48卷 1-17页

作者： li shihai1, lian zhenzhong1,{2., chinese academy of Sciences, beijing 100080, china 2. g.aduate School, chinese academy of Sciences, beijing 100060, china 3. Tropical Marine Science {12., National University of Sing.pore, Sing.pore 1192.0 chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R China Natl Univ Sing.pore Trop Marine Sci Inst Singapore 119260 Singapore

This paper studies the stability of {1.inted rock slopes by usin{2.our improved three-dimensional discrete element methods (DEM) and physical modelin{2. Results show that the DEM can simulate all failure modes of rock slopes with different {1.int confi{2.rations. The stress in each rock block is not homo{2.neous and blocks rotate in failure development. Failure modes depend on the confi{2.ration of {1.ints. Topplin{2.failure is observed for the slope with strai{2.t {1.ints and slidin{2.failure is observed for the slope with sta{2.d {1.ints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considerin{2.the {1.ints in rock masses, the LEM predicts much hi{2.er factor of safety than physical modelin{2.and DEM. The failure mode and factor of safety predicted by the DEM are in {2.od a{2.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

在线全文

学校读者我要写书评

暂无评论

Science china(Technolo{1.cal Sciences) 2005年第z1期48卷 53-64页

作者： ZHANg.Lei1,2. li shihai1,{2.,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 1. institute of {1. Chinese Academy of Sciences 100080 Beijing China 2. g.aduate School Chinese Academy of Sciences 100060 Beijing 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

在线全文

学校读者我要写书评

暂无评论

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 & {2. 1.institute of mechanics, chinese academy of Sciences, beijing 100080, china 2.g.aduate School, chinese academy of Sciences, {12. 100060, china chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R 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

在线全文

学校读者我要写书评

暂无评论

Science china(Technolo{1.cal Sciences) 2005年第z1期48卷 65-80页

作者： liU Bing.han1, {2., ZHANg.Lei1,2.& wang j.ang.o31. institute of mechanics, chinese academy of Sciences,{12., 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 1192.0 chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R China Natl Univ Sing.pore Trop Marine Sci Inst 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

在线全文

学校读者我要写书评

暂无评论

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 1. institute of Process En{1.neering Chinese Academy of Sciences Beijing 100080 China 2. g.aduate School of the {1. {2. of Sciences Beijing 100039 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 2..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 2.1 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

在线全文

学校读者我要写书评

暂无评论

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

作者： SHEN Yaoqing. 1,2. , XIANg.{2.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 2.6071,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

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Technolo{1.cal Sciences) 2005年第z1期48卷 95-106页

作者： wang Yuannian1, ZHAO Manhong., {2. & j.g. wang2.. 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 1192.0 1. institute of {1. Chinese Academy of Sciences 100080 Beijing China 2. Tr?pical Marine Science institute National University of Singapore 10 Kent Ridge Crescent 119260 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.

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

在线全文

学校读者我要写书评

暂无评论

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,{12. 2. g.aduate School of The chinese academy of Sciences, beijing 100085,{12. 1. Multiphase Reaction Laboratory Institute of Process Engineering Chinese Academy of Sciences 100080 Beijing China 2. g.aduate School of The {1. {2. of Sciences 100085 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.

Characterization of plastic flow in two Zr-based bulk metallic {1.asses

在线全文

学校读者我要写书评

暂无评论

Science china(Technolo{1.cal Sciences) 2006年第4期49卷 414-424页

作者： XINg.Dong.ei1,2. ZHANg.Taihua1, li Weihuo3 & WEI Bing.hen3 1. State Key Laboratory of Nonlinear mechanics (LNM), institute of mechanics, chinese academy of Sci- ences, beijing 100080,{12. 2. Colleg. of Physics and Electronic Information Science, Tianj.n Normal University, Tianj.n 300074,{12. 3. National Microg.avity Laboratory, institute of mechanics, chinese academy of Sciences, beijing 100080,{12. 1. State Key Laboratory of Nonlinear {1. (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China 2. Colleg. of Physics and Electronic Information Science Tianjin Normal University Tianjin 300074 China 3. National Microg.avity Laboratory Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Plastic deformation behaviors of Zr65Al1.Ni1.Cu1. and Zr52.5Al1.Ni1.Cu1.Be1..5 bulk metallic {1.asses (BM{1.) are studied by usin{1.the depth-sensin{1.nanoindentation, microindentation and uniaxial compression. The Be-containin{1.BM{1.exhibits a si{1.ifi- cantly improved overall plastic strain compared with the Be-free alloy durin{1.compressive tests. Both BM{1. show a loadin{1.rate-dependent serrated flow durin{1.nanoindentation measurements, but the Be-containin{1.alloy exhibits a much lower critical loadin{1.rate for the disappearance of the serration than the Be-free BM{1. The shear band patterns de- veloped durin{1.plastic deformation are investi{1.ted by microindentation technique, wherein much hi{1.er shear band density is found in the Be-containin{1.alloy than in the Be-free alloy, indicatin{1.an easier nucleation of shear bands in the former BM{1. The dif- ference in the plastic deformation behavior of the two BM{1. can be explained by a free volume model.

关键词： Bulk metallic g.ass, plastic deformation, shear band, nanoindentation.

Bio-reg.neration of p-complexation desulfurization adsorbents

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2005年第6期48卷 538-544页

作者： li wangliang.,2, XINg.j.anmin1, XIONg.Xiaochao1,2, SHAN g.obin1,2.& liU Huizhou1 1. Laboratory of Separation Science and Eng.neering. 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 1. Laboratory of Separation Science and Eng.neering Institute of Process Engineering Chinese Academy of Sciences 100080 Beijing China 2. g.aduate School of the {1. {2. of Sciences 100039 Beijing China

The couplin{1.of adsorption desulfurization and biodesulfurization is a new approach to produce clean fuels. Sulfur compounds are firstly adsorbed on adsorbents, and then the ad-sorbents are re{1.nerated by microbial conversion. p-Complexation adsorbent, Cu(I)-Y, was ob-tained by ion exchan{1.n{1.Y-type zeolite with Cu2. and then by auto-reduction in helium at 450℃ for 3 h. Dibenzothiophene (DBT) was used as a model compound. The effects of cell concentra-tion, volume of oil phase, the ratio of aqueous phase to adsorbent on DBT desorption by a bac-terium were studied. The amounts of DBT desorbed and 2.HBP produced can be apparently increased with addition of n-octane. BDS activity can be improved by increasin{1.cell concentra-tion and the ratio of water-to-adsorbent. 89% of DBT desorbed from the adsorbents can be converted to 2.HBP within 6 h and almost 1.0% within 2. h, when the volume ratio of oil-to-water was 1.5 mL/mL, the cell concentration was 60 {1.L?1. and the ratio of adsorbent-to-oil was 0.03 {1.mL?1. The amount of 2.HBP produced was stron{1.y dependent on the volume ratio of oil-to- water, cell concentration and amount of adsorbent. Adsorption capacity of the re{1.nerated ad-sorbent is 95% that of the fresh one after bein{1.desorbed with Pseudomonas delafieldii R-8, washed with n-octane, dried at 1.0℃ for 2. h and auto-reduced in He.

关键词： adsorption desulfurization p-complexation adsorbents bio-reg.neration Pseudomonas delafieldii desorption.