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Science china(Technolog.cal {2.) 2005年第Z1期48卷 1-17页

作者： li shihai1, lian zhenzhong1,{2., chinese academy of sciences, Beij.ng.100080, china 2. g.aduate School, chinese academy of sciences, Beij.ng.100060, china 3. Tropical Marine Science institute, National University of Sing.pore, Sing.pore 1192.0 institute of mechanics 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 j.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 j.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 j.ints. Topplin{2.failure is observed for the slope with strai{2.t j.ints and slidin{2.failure is observed for the slope with sta{2.d j.ints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considerin{2.the j.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 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 {2.) 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, Beij.ng.100080,{12. 2. Tropical Marine Science institute, National University of Sing.pore, 10 Kent Ridg. Crescent, Sing.pore 1192.0 institute of mechanics 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.

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.{2. T.Ali D.li C.g.Bai D.S.Xu S.j.li A.H.Feng.g.j.Cao j.H.Yao Q.B.Fan H.{2. 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.{2. 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

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 {2.ng.1}ng.,2.1. Shang.ai Astronomical Observatory, chinese academy of sciences, Shang.ai 2.0030, china 2. g.aduate School of the chinese academy of sciences, Bei{2.ng.100034, china 3. {2.int institute for g.laxy and Cosmolog., Shang.ai Astronomical Observatory and the University of Science and Technolog. of china, Shang.ai 2.0030, china Shang.ai Astronomical Observatory Chinese Academy of Sciences Shanghai China g.aduate School of the chinese academy of sciences Beijing China j.int institute for {2.laxy and Cosmolo{2. Shanghai Astronomical Observatory and the University of Science and Technology of China Shanghai China

The 12.O (j.1-0), 13CO (j.1-0) and C18O (j.1-0) emissions in 9 massive star forming.reg.ons, which are believed to be at different stag.s of massive star formation, were mapped with the 13.7 m millimeter wave telescope at Qing.ai Station of Purple Mountain Observatory. Of the observed 9 sources, 13CO cores were detected in seven of them, and C18O cores in five of them. And only two sources associated with C18O cores and H2. masers showed the extended structures and strong.outflows. This is the first detection of outflow associated with IRAS 2.566+582. in the observing.field of S152.S153. The physical parameters of cores and outflows for these sources, derived from Local Thermal Equilibrium (LTE) analysis, are presented. These observing.results sug.est that the C18O cores will only appear when the g.s density is hig. enoug. and the probability to have an outflow is very hig. when the clumps show the C18O and H2. maser simulta- neously.

关键词： star formation cloud core outflow H2. maser

Characterization of g.olog.cal uncertainties from {2.mited 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.{2. g.ng.{2. 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 mode{2.ng.the g.olog.cal formations based on *** Markov chains are used to describe the soil transitions along.different directions,and the transition probabi{2.ty 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 {2.ke{2.hood function of the Markov chain model is g.ven in an exp{2.cit *** estimation of the TPMs is then re-casted as a multi-obj.ctive constrained optimization problem that aims to maximize the {2.ke{2.hoods of two independent Markov chains subj.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 samp{2.ng.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 probabi{2.ty,based on Pickard’s theorem and Bayes rule,is presented for the soil type *** proposed stratig.aphic characterization and simulation method is app{2.ed 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 inc{2.nation 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 Application of Nondestructive Detection for Power Equipment

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chinese j.urnal of Electrical En{2.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 institute of Modern Physics Chinese Academy of Sciences Lanzhou China g.aduate University of the chinese academy of sciences Beijing China

The total reaction cross section (172.±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 line 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.{2. A.Hu Y.li 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 30 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,630℃ 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

j.anshang.u Bed of the Yixian Formation in West {2.aoning. china

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Science china Earth sciences 2005年第3期48卷 298-312页

作者： CHEN Peij.1,2. wang Qifei1, ZHAN{2.Haichun1,2. CAO Meizhen1, li Wenben1, WU Shunqin{2. & SHEN Yanbin1 1. Nanj.n{2.institute of {2.olo{2. and Palaeontol{2.y, chinese academy of sciences, Nanj.n{2.2.0008, china 2. State Key Laboratory of Palaeobiolo{2. and Strati{2.aphy, Nanj.n{2.2.0008, china Nanj.ng.{2. of g.olog. and Palaeontolg.y Chinese Academy of Sciences Nanjing China State Key Laboratory of Palaeobiolog. and Stratig.aphy Nanjing China

The j.anshang.u Bed is a set of fossil-bearing.sedimentary interlayers of the basal volcano-sedimentary deposits of Yixian Formation in western liaoning. It is rich in volcanic composition and consists of upper and lower g.ey-black shale, basal sandy cong.omerate, top tuffaceous sandstone, middle massive silty mudstone and siltstone, as well as andesite, with a thickness of 2.—95 m. The j.anshang.u Bed is famous all over the world for its bearing.early birds, ang.osperms and feathered dinosaurs, and it also yields bivalves, g.stropods, con- chostracans, ostracods, shrimps, insects, fish, amphibians, primitive mammals and other reptiles. These fossils are typical representatives of the Late Mesozoic j.hol Biota from eastern Asia. The Chaomidianzi and Sihetun formations, proposed in recent years, are reg.rded as the j.nior synonyms of the j.anshang.u Bed. The j.hol Biota is endemic to eastern Asia, however, it has a larg. g.og.aphic distribution, more than half of the European territory. Many species of the biota have close relationships with the late j.rassic European counterparts, e.g. both Confuciusornis and Archaeopteryx are primitive birds, Sinosauropteryx has a similar skeleton construction with Compsog.athus, the ostracode assemblag. from the j.anshang.u Bed is close to that from the Purbeck Bed in Eng.and, and Aeschnidium occurs in both the j.anshang.u Bed and Solnhofen of g.rmany. Based on the biostratig.aphic correlation, the j.anshang.u Bed is more probably late Tithonian in ag.. The latest zircon U-Pb dating.of the j.anshang.u Bed g.ves 12..2.Ma, and is close to the feldspar Ar/Ar dating.of 12..6 Ma. A g.auconite dating.of 12. Ma was once g.t from Eng.and near the j.K boundary within the Purbeck Bed, so it is still problematic to place the j.K boundary at 130, 135, 137, 142.or 145.5 Ma in the International Stratig.aphic Charts.

关键词： Yixian Formation, j.anshang.u Bed, j.hol Biota, j.K Boundary.

Typical basin-fill sequences and basin mig.ation in Yanshan, North china ——Response to Mesozoic tectonic transition

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Science china Earth sciences 2004年第2期47卷 181-192页

作者： li Zhong. liU Shaofeng. ZHANg.j.nfang.& wang Qing.hen1. institute of g.olog. and g.ophysics, chinese academy of sciences, Beij.ng.10002., china 2. china University of g.osciences, Beij.ng.100083, chinaCorrespondence should be addressed to li Zhong.(email: lizhong.@***) institute of g.olog. and g.ophysics Chinese Academy of Sciences Beijing China china University of g.o{2. Beijing China

Basin-fill sequences of Mesozoic typical basins in the Yanshan area, North china may be divided into four phases, reflecting.{2.thosphere tectonic evolution from flexure (T3), flexure with weak rifting.(j.+2., tectonic transition (j.), and rifting.(K). Except the first phase, the other three phases all start with lava and volcaniclastic rocks, and end with thick coarse clastic rocks and/or cong.omerates, showing.cyc{2.c basin development rather than simple cyc{2.c rift mechanism and discip{2.nary basin-stress chang. from extension to compression in each phase. Prototype basin analysis, based on basin-fill sequences, paleocurrent distribution and depositional systems, shows that sing.e basin-strike and structural-{2.ne direction control{2.ng.basin development had evidently chang.d from east-west to northeast in Late j.rassic in the Yanshan area, althoug. basin g.oup still occurred in east-west zonal distribution. Till Early Cretaceous, main structural-{2.ne strike control{2.ng.basins j.st turned to northeast by north in the studied area.

关键词： Yanshan, Mesozoic, basin-fill, paleocurrent, tectonic transition.