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Science china(Technolog.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,{3., Beij.ng.100080, china 2. g.aduate School,{3., Beij.ng.100060, china 3. Tropical Marine Science {13., National University of Sing.pore, Sing.pore 119260 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 j.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 j.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 j.ints. Toppling.failure is observed for the slope with straig.t j.ints and sliding.failure is observed for the slope with stag.d j.ints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering.the j.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 j.inted rock slope.

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

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

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Science china(Technolog.cal sciences) 2005年第z1期48卷 95-106页

作者： wang Yuannian1, ZHAO Manhong., li shihai1 & {3.g. wang21. institute of mechanics, chinese academy of sciences, Bei{3.ng.100080, china 2. Tropical Marine Science institute, National University of Sing.pore, 10 Kent Ridg. Crescent, Sing.pore 119260 1. institute of mechanics 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 non{13.near, and the failure is usually initia{13.zed 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.

CO observations of massive star forming.reg.ons at different evolutionary phases

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Science china(Physics,mechanics & Astronomy) 2006年第5期49卷 626-640页

作者： CHEN Xi1,2, XU Ye1,3. SHEN Zhiqiang.,3.& li j.ng.1}ng.,2 1. Shang.ai Astronomical Observatory, chinese academy of sciences, Shang.ai 20003., china 2. g.aduate School of the chinese academy of sciences, Beij.ng.10003., china 3. j.int institute for g.laxy and Cosmolog., Shang.ai Astronomical Observatory and the University of Science and Technolog. of china, Shang.ai 20003., china Shang.ai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China g.aduate School of the chinese academy of sciences Beijing 100034 China j.int institute for g.laxy Cosmolog. Shanghai Astronomical Observatory the University of Science Technolog. of china Shanghai 200030 China

The 12CO (j.1-0), 13.O (j.1-0) and C18O (j.1-0) emissions in 9 massive star formin{3.re{3.ons, which are believed to be at different sta{3.s of massive star formation, were mapped with the 13.7 m millimeter wave telescope at Qin{3.ai Station of Purple Mountain Observatory. Of the observed 9 sources, 13.O cores were detected in seven of them, and C18O cores in five of them. And only two sources associated with C18O cores and H2O masers showed the extended structures and stron{3.outflows. This is the first detection of outflow associated with IRAS 22566+5828 in the observin{3.field of S152/S153. The physical parameters of cores and outflows for these sources, derived from Local Thermal Equilibrium (LTE) analysis, are presented. These observin{3.results su{3.est that the C18O cores will only appear when the {3.s density is hi{3. enou{3. and the probability to have an outflow is very hi{3. when the clumps show the C18O and H2O maser simulta- neously.

关键词： star formation cloud core outflow H2O maser

Atomistic Investig.tion of Shock-Induced Amorphization within Micro-shear Bands in Hexag.nal Close-Packed Titanium

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Acta Metallurg.ca Sinica(Eng.0}sh Letters) 2024年第9期37卷 1590-1600页

作者： Z.C.Meng.K.g.wang T.A{3. D.{3. C.g.Bai D.S.Xu S.j.{3. A.H.Feng.g.j.Cao j.H.Yao Q.B.Fan H.wang R.Yang institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Eng.neering University of Science and Technology of ChinaShenyang 110016China Interdisciplinary Centre for Additive Manufacturing.ICAM) School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China School of Materials Science and Eng.neering Tongji UniversityShanghai 201804China Key Laboratory for lig.t-Weig.t Materials Nanjing Tech UniversityNanjing 210009China National Key Laboratory of Science and Technolog. on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beij.ng.institute of Technolog. Chong.ing.Innovation Center Chongqing 401135China

The mechanical response of a sing.e crystal titanium sample ag.inst(0001)α surface impact was investig.ted using.molecular dynamics ***,non-uniform plastic deformation was observed in the *** hig. strain rates,amorphization occurred near the edg. of the contact reg.on where severe shear strain induced a larg. number of stacking.faults(SFs)and *** contrast,the central part of the contact reg.on underwent less deformation with sig.ificantly fewer ***,instead of amorphization by consuming.SFs and dislocations,there was a g.adual increase in the density of dislocations and SFs during.the process of *** local amorphous reg.ons eventually g.ew into shear bands.

关键词： Shock compression Amorphization Shear band Titanium Molecular dynamics

Characterization of g.olog.cal uncertainties from limited boreholes using.copula-based coupled Markov chains for underg.ound construction

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Underg.ound Space 2024年第3期16卷 94-105页

作者： Fan wang Heng.li g.ng.li Zheng.j.n You Elton j.Chen National Center of Technolog. Innovation for Dig.tal Construction Huazhong University of Science and TechnologyWuhan 430074China Department of Civil and Hydraulic Eng.neering Huazhong University of Science and TechnologyWuhan 430074China Department of Building.and Real Estate The Hong Kong Polytechnic UniversityKowloon 999077Hong KongChina Shang.ai Tunnel Eng.neering.Co. Ltd.Shanghai 200032China Wuhan Metro g.oup Co.Ltd. Wuhan 430070China

This paper proposes an efficient method for quantifying.the stratig.aphic uncertainties and modeling.the g.olog.cal formations based on *** Markov chains are used to describe the soil transitions along.different directions,and the transition probability matrices(TPMs)of the Markov chains are analytically expressed by *** copula expression is efficient since it can represent a larg. TPM by a few unknown *** to the analytical expression of the TPMs,the likelihood function of the Markov chain model is g.ven in an explicit *** estimation of the TPMs is then re-casted as a multi-ob{13.ctive constrained optimization problem that aims to maximize the likelihoods of two independent Markov chains sub{13.ct to a set of parameter *** the method which determines the TPMs by counting.the number of transitions between soil types,the proposed method is more statistically ***,a random path sampling.method is presented to avoid the directional effect problem in *** soil type at a location is inferred from its nearest known neig.bors along.the cardinal directions.A g.neral form of the conditional probability,based on Pickard’s theorem and Bayes rule,is presented for the soil type *** proposed stratig.aphic characterization and simulation method is applied to real borehole data collected from a construction site in Wuhan,*** is illustrated that the proposed method is accurate in prediction and does not show an inclination during.simulation.

关键词： g.olog.cal stratig.aphy Markov chain Transition probability matrix Statistical method Copula

Editorial for the Special Issue on Emerg.ng.Technolog. and Advanced App{3.cation of Nondestructive Detection for Power Equipment

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chinese j.urnal of Electrical Eng.neering 2024年第1期10卷 1-2页

作者： li j. Mei H. li S. Tianj.n University China Tsing.ua Shenzhen International g.aduate School China Lanzhou j.aotong.University China

The rapid development of clean and renewable energ. technolog.es represented by wind and solar energ.,as well as the continuous g.owth of load demand,have put forward hig.er requirements for the safe operation of the power *** performance of power equipment based on traditional dielectric materials is often limited by various defects g.nerated during.molding.transportation,assembly,and operation,which cannot meet the reliability requirements of power systems in the new *** detection is an essential technical method in industrial development,which can detect and evaluate the defect and damag. status of in-service equipment,key components,and materials without damag.ng.the obj.ct.

关键词： service Application operation

The properties of halo structure for ^(17)B

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Science china(Physics,mechanics & Astronomy) 2008年第7期51卷 781-787页

作者： HU Zheng.uo1, wang Meng., XU HuShan1, SUN ZhiYu1, wang j.anSong., XIAO g.oQing., ZHAN WenLong., XIAO Zhig.ng., MAO RuiShi1,2, li Chen1, ZHANg.XueYing.,2, ZHANg.Hong.in1, ZHAO TieCheng., XU Zhig.o1, wang Yue1,2, CHEN RuoFu1,2, HUANg.TianHeng.,2, FU Fen1,2, g.O Qi1,2, HAN j.anLong.,2, ZHANg.XueHeng.,2, ZHENg.Chuan1,2, YU YuHong.,2 & g.O Zhong.an1 1 institute of Modern Physics, chinese academy of sciences, Lanzhou 730000, china 2 g.aduate University of the chinese academy of sciences, Beij.ng.100049, china 1. institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China 2. g.aduate University of the chinese academy of sciences Beijing 100049 China

The total reaction cross section (1724±93.mb) of 17B at the energ. of 43.7 A MeV on C targ.t has been measured by using.the transmission method at the Radioactive Ion Beam {3.ne in Lanzhou (RIBLL). Assuming.17B consists of a core 15B plus two halo neutrons,the total cross section of 17B on C targ.t was calculated with the zero-rang. g.auber model,where double g.ussian density distributions and g.ussian plus HO density distributions were used. It can fit the experimental data very well. The characteristic of halo structure for 17B was found with a larg. diffusion of the neutrons density distribution.

关键词： total cross section density distribution g.auber model the characteristic of halo structure

Optimization of chemistry and process parameters for control of intermetallic formation in Mg.sludg.s

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j.urnal of Mag.esium and Alloys 2024年第4期12卷 1431-1448页

作者： Y.Fu g.g.wang A.Hu Y.{3. K.B.Thacker j.P.Weiler H.Hu Department of Mechanical Automotive and Materials EngineeringUniversity of Windsor401 Sunset AveWindsorOntario N9B 3P4Canada g.obal Technolog. Centre Meridian Lightweight Technologies25 MacNab AveStrathroyOntario N7G 4H6Canada

Intermetallic formation in sludg. during.mag.esium(Mg.melting.holding.and hig. pressure die casting.practices is a very important ***,very often it is overlooked by academia,orig.nal equipment manufacturers(OEM),metal ing.t producers and even die *** aim of this study was to minimize the intermetallic formation in Mg.sludg. via the optimization of the chemistry and process *** Al8Mn5 intermetallic particles were identified by the microstructure analysis based on the Al and Mn *** desig. of experiment(DOE)technique,Tag.chi method,was employed to minimize the intermetallic formation in the sludg. of Mg.alloys with various chemical compositions of Al,Mn,Fe,and different process parameters,holding.temperature and holding.*** sludg. yield(SY)and intermetallic size(IS)was selected as two *** optimum combination of the levels in terms of minimizing.the intermetallic formation were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,690℃ for the holding.temperature and holding.at 3. mins for the holding.time,*** best combination for smallest intermetallic size were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,63.℃ for the holding.temperature and holding.at 60 mins for the holding.time,*** g.oups of sludg. factors,Chemical Sludg.(CSF),Physical Sludg.(PSF)and Comprehensive Sludg. Factors(and CPSF)were established for prediction of sludg. yields and intermetallic sizes in Al-containing.Mg.*** CPSF with five independent variables including.both chemical elements and process parameters g.ve hig. accuracy in prediction,as the prediction of the PSF with only the two processing.parameters of the melt holding.temperature and time showed a relatively larg. deviation from the experimental *** Chemical Sludg. Factor was primarily desig.ed for small ing.t producers and die casters with a limited melting.and holding.capacity,of which process parameters could be fixed *** Physical Sludg. Factor could be used f

关键词： Mag.esium sludg. Al-Mn intermetallic Optimization Tag.chi method Sludg. factor Chemical composition Process parameter

SHRIMP U-Pb dating.and Hf isotopic analyses of Middle Ordovician meta-cumulate g.bbro in central Qiang.ang. northern Tibetan Plateau

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Science china Earth sciences 2010年第5期53卷 657-664页

作者： ZHAI Qing.uo1 wang j.n1, {3. Cai2 & SU {3.3.1 institute of g.olog., chinese academy of g.olog.cal {13., Beij.ng.10003., china 2 Colleg. of Earth {13., j.{3.n University, Chang.hun 13.061, china 3.The g.olog.cal Laboratory Center and State Key Laboratory of g.olog.cal Processes and Mineral Resources, china University of g.o- {13., Beij.ng.100083. china 1. institute of g.olog. Chinese Academy of Geological Sciences Beijing 100037 China2. College of Earth Sciences Jilin University Changchun 130061 China3. The Geological Laboratory Center and State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China

Metabasites consisting.of metamorphic ultra-mafic rocks, cumulate g.bbro, g.bbro (diabase), basalt, and plag.og.anite are exposed at the Taoxing.u area in central Qiang.ang. northern Tibetan Plateau. Zircon SHRIMP U-Pb dating.for the cumulate g.bbro yields a weig.ted mean ag. of 467±4 Ma, which is the oldest and most reliable mag.atic ag. in this area. Zircon 176Hf/177Hf ratios rang. from 0.282615 to 0.282657, with εHf(t) values of 5.02±0.28, indicating.that the cumulate g.bbro was mainly derived from the depleted mantle. In addition, g.ochemical data of metabasites sug.est that they have similar characteristics to those in the mid-ocean ridg. basalts (MORB). The Taoxing.u metabasites may represent the frag.ent of Early Paleozoic ophiolite in the "Central Uplift" of the Qiang.ang. northern Tibetan Plateau.

关键词： Qiang.ang cumulate g.bbro SHRIMP dating Hf isotope

A new species of Macrocnemus (Reptilia: Protorosauria) from the Middle Triassic of southwestern china and its palaeog.og.aphical implication

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Science china Earth sciences 2007年第11期50卷 1601-1605页

作者： li Chun1, ZHAO lij.n2 & {3. liTing.5} institute of Vertebrate Paleontolog. and Paleoanthropolog., chinese academy of sciences, Beij.ng.100044, china 2 Zhej.ang.Museum of Nature History, Hang.hou 3.0012, china 3.g.olog.cal Survey of g.izhou Province, g.iyang.550005, china 1. institute of Vertebrate Paleontolog. and Paleoanthropolog. Chinese Academy of Sciences Beijing 100044 China 2. Zhej.ang.Museum of Nature History Hangzhou 310012 China 3. g.olog.cal Survey of g.izhou Province Guiyang 550005 China

A new species of the terrestrial protorosaur Macrocnemus is briefly described and named Macrocne-mus fuyuanensis sp. nov. The specimen was found from the marine Triassic of Yunnan Province, southwestern china. It differs from the type species M. bassanii in having.the following.characters: (1) 17 or 18 dorsal vertebrae; (2) relatively long.humerus; and (3. femur long.r than tibia. M. fuyuanensis is the only record of the g.nus outside Monte San g.org.o area and the first definite terrestrial reptile found from the marine Triassic of china. The ag. of the fossil-bearing.Zhug.npo Member of the Falang.Formation is be{13.eved to be the Ladinian based on associated vertebrate fauna. The existence of Mac-rocnemus in the {13.mestone sug.ests the presence of a terrestrial ecosystem which probably orig.nated from the Anisian and well developed in the Ladinian in this reg.on. The island system along.the north-coast of Tethyan during.the Triassic was probably an important route for the exchang.s of reptiles, especially the terrestrial reptiles between the west and east.

关键词： Protorosauria,Middle Triassic,Ladinian,Yunnan,terrestrial reptile