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Experimental and discrete element numerical analysis of side slope instability induced by fissure water underlying impervious bed

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Science China(Technological sciences) 2005年第z1期48卷 65-80页

作者： liu bingshan1, li shihai1,{2.,{3., Chinese academy of sciences, beijing 100080, China 2. Graduate School, Chinese academy of sciences, beijing 100060, China 3. Tropical Marine Science institute, National University of Singapore, 10 Kent Ridge Crescent, Singapore 1192.0 Chinese Acad Sci Inst Mech Beijing 100080 Peoples R China Chinese Acad Sci Grad Sch Beijing 100060 Peoples R China Natl Univ Singapore Trop Marine Sci Inst Singapore 119260 Singapore

When the sliding mass contains impervious bed, rainfall can infiltrate into mountain via crevices and form higher artesian aquifer at impervious bed inferior. This will decrease slip resistance and increase sliding forces of the sliding mass, thus lowering the safety factor, and inducing landslide disasters. In this paper, a landslide experimental apparatus is designed for experimental studies on the mechanism of this type of landslides. Meanwhile, the non-dimensional parameters in the model experiment are taken into account using dimensional analysis. The experimental results show that (1) the ratio of the cleft water pressure to the overlying pressure is a crucial parameter affecting 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 overlying rock and soil on the upper 3.% area. In this article, a discrete element method simulation is used to investigate the influence of cleft water pressure and shearing strength 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 high 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.

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Experimental investigation and numerical simulation on the effect of fissure water pressure in vertical sliding surface

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Science China(Technological sciences) 2005年第z1期48卷 53-64页

作者： zhang lei1,2.{2., liAN Zhenzhong1,2.& {3. Yuannian1 1. institute of mechanics, Chinese academy of sciences, beijing 100080, China 2. Graduate School, Chinese academy of sciences, beijing 100060, China 1. institute of mechanics Chinese Academy of Sciences 100080 Beijing China 2. Graduate School Chinese Academy of Sciences 100060 Beijing China

This paper studies the effect of fissure water pressure in different fractures on the critical angle of landslide by laboratory investigation 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 angle of landslide is little when the distance between water-holding fracture and slope toe is three times greater 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 angle of jointed slope when fissure water pressure in vertical sliding surface exists. Numerical results are in good agreement 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 justify the effect of fissure water pressure on the critical angle of landslide.

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

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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(Technological sciences) 2005年第z1期48卷 146-156页

作者： zhang lei1,2. WEI Zuoan1, {2. Xiaoyu1 & li shihai1 1.{3. of mechanics, Chinese academy of sciences, beijing 100080, China 2.Graduate School, Chinese academy of sciences, {13. 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-stage process of landslide under fissure water pressure in the opencast mine, according to the actual state of landslide in Panluo iron mine where landslide happened in 1990 and was fathered in 1999. The calculation results show that fissure water pressure on the sliding surface is the main reason causing 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 good agreement; 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 engineering 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.

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A mixed method for measuring low-frequency acoustic properties of macromolecular materials

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Science China(Physics,mechanics & Astronomy) 2006年第6期49卷 729-739页

作者： liu Hongwei1,YAO lei1,3.ZHAO Hong1,3.{2. Jichuan2.3.& XUE Zhaohong2.1. National Key Laboratory of Acoustics,institute of Acoustics,Chinese {3. of sciences,beijing 100080,China 2. institute of Chemistry,Chinese {3. of sciences,beijing 100080,China 3. Graduate University of Chinese {3. of sciences,beijing 100049,China National Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing 100080 China institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Graduate University of Chinese academy of sciences Beijing 100049 China

A mixed method for measuring low-frequency acoustic properties of macro-molecular materials is presented. The dynamic mechanical parameters of materials are first measured by using Dynamic Mechanical Thermal Apparatus(DMTA) at low frequen-cies,usually less than 100 Hz; then based on the Principles of Time-Temperature Super-position (TTS),these parameters are extended to the frequency range that acousticians are concerned about,usually from hundreds to thousands of hertz; finally the extended dynamic mechanical parameters are transformed into acoustic parameters with the help of acoustic measurement and inverse analysis. To test the feasibility and accuracy,we measure a kind of rubber sample in DMTA and acquire the basic acoustic parameters of the sample by using this method. While applying the basic parameters to calculating characteristics of the sample in acoustic pipe,a reasonable agreement of sound absorp-tion coefficients is obtained between the calculations and measurements in the acoustic pipe.

关键词： low-frequency acoustic properties,dynamic mechanical properties,Principles of Time-Temperature Superposition,acoustic pipe,sound absorption coefficient.

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Establishing cell suitability for high-level production of licorice triterpenoids in yeast

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Acta Pharmaceutica Sinica B 2024年第9期14卷 4134-4148页

作者： Wentao Sun Shengtong Wan Chuyan liu Ruwen wang Haocheng {2. {3. Qin Runming wang Bo Lv Chun li Department of Chemical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering Ministry of Industry and Information TechnologyInstitute of Biochemical EngineeringSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China The University of Chicago ChicagoIL 60637USA Key Lab for Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084China Center for Synthetic and Systems Biology Tsinghua UniversityBeijing 100084China institute of Biopharmaceutical and Health Engineering Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

Yeast has been an indispensable host for synthesizing complex plant-derived naturalcompounds, yet the yields remained largely constrained. This limitation mainly arises from overlookingthe importance of cell and pathway suitability during the optimization of enzymes and pathways. Herein,beyond conventional enzyme engineering, we dissected metabolic suitability with a framework forsimultaneously augmenting cofactors and carbon flux to enhance the biosynthesis of heterogenoustriterpenoids. We further developed phospholipid microenvironment engineering strategies, dramaticallyimproving yeast’s suitability for the high performance of endoplasmic reticulum (ER)-localized, ratelimitingplant P450s. Combining metabolic and microenvironment suitability by manipulating only threegenes, NHMGR (NADH-dependent HMG-CoA reductase), SIP4 (a DNA-binding transcription factor)andGPP1 (Glycerol-1-phosphate phosphohydrolase 1), we enabled the high-level production of 4.92.g/L rarelicorice triterpenoids derived from consecutive oxidation of b-amyrin by two P450 enzymes afterfermentation optimization. This production holds substantial commercial value, highlighting the criticalrole of establishing cell suitability in enhancing triterpenoid biosynthesis and offering a versatileframework applicable to various plant natural product biosynthetic pathways.

关键词： Cell suitability Phospholipid microenvironment Cytochrome P450 Triterpenoids Saccharomyces cerevisiae

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Compression behavior of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(2..5) bulk metallic glass up to 2. GPa

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Science China(Physics,mechanics & Astronomy) 2005年第3期48卷 319-324页

作者： li Gong 1, 2., ZHAN Zaiji 2., {3. Jing 3., YUN Jinku 1 , SUN liling 2., {3. Riping 1 , zhang Jun 2.& wang Wenkui 1, 2.1. Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China 2. Center for Condensed Matter Physics, {13. of Physics, Chinese {3. of sciences, beijing 100080, China 3. BSRF, {13. of High Energy Physics, Chinese {3. of sciences, beijing 10003., China 1. Key Laboratory of Metastable Materials Science and Technology Yanshan University 066004 Qinhuangdao China 2. Center for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences 100080 Beijing China 3. BSRF Institute of High Energy Physics Chinese Academy of Sciences 100039 Beijing China

The compression of a Zr41Ti14Cu12.5Ni10Be2..5 bulk metallic glass (BMG) is investigated at room temperature up to 2. GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The pressure-induced structural relaxation is exhibited. It is found that below about 8 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to the rapid volumetric change, and the structural relaxation results in the structural stiffness under higher pressure.

关键词： bulk metallic glass, high pressure, structural relaxation, synchrotron radiation.

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Characterization of plastic flow in two Zr-based bulk metallic glasses

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Science China(Technological sciences) 2006年第4期49卷 414-424页

作者： XING Dongmei1,2. zhang Taihua1, li Weihuo3.& WEI Bingchen3.1. State Key Laboratory of Nonlinear mechanics (LNM), institute of mechanics, Chinese academy of Sci- ences, beijing 100080, China 2. College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 3.0074, China 3. National Microgravity Laboratory, institute of mechanics, Chinese academy of {13., beijing 100080, China 1. State Key Laboratory of Nonlinear mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China 2. College of Physics and Electronic Information Science Tianjin Normal University Tianjin 300074 China 3. National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Plastic deformation behaviors of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glasses (BMGs) are studied by using the depth-sensing nanoindentation, microindentation and uniaxial compression. The Be-containing BMG exhibits a signifi- cantly improved overall plastic strain compared with the Be-free alloy during compressive tests. Both BMGs show a loading-rate-dependent serrated flow during nanoindentation measurements, but the Be-containing alloy exhibits a much lower critical loading rate for the disappearance of the serration than the Be-free BMG. The shear band patterns de- veloped during plastic deformation are investigated by microindentation technique, wherein much higher shear band density is found in the Be-containing alloy than in the Be-free alloy, indicating an easier nucleation of shear bands in the former BMG. The dif- ference in the plastic deformation behavior of the two BMGs can be explained by a free volume model.

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

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Fabricating bio-inspired high impact resistance carbon nanotube network films for multi-protection under an extreme environment

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Nano Research 2024年第9期17卷 7793-7802页

作者： Mingquan Zhu Kailu Xiao Wei zhang Xudong lei Yunxiang Bai Shijun {2. Peng zhang Feng Gao Congying {2. Wenqiang Xu Huiyong li Xianqian Wu Chao {2. Hui zhang Luqi liu Zhong zhang CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China University of Chinese academy of sciences Beijing 100049China Department of Materials Science and Engineering Texas A&M UniversityCollege StationTexas 77840USA institute of mechanics Chinese Academy of SciencesBeijing 100190China School of Astronautics Harbin Institute of TechnologyHarbin150001China CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230027China

The fabrication of light-weight,highly impact-resistant,and energy-absorbent materials is urgently demanded in many facets of the society from body armor to aerospace engineering,especially under an extreme *** nanotubes(CNTs),one of the strongest and toughest materials ever found,also have good conductivity,chemical stability,and thermal stability,etc,making them a competitive candidate as building blocks to help achieve the above *** this work,a kind of CNT network was prepared by using chlorosulfonic acid(CSA)to release the internal stress of super-aligned carbon nanotube films(SA-CNTF)and dendritic polyamide amine(PAMAM)to further introduce multiple hydrogen bonds and interlocking *** fabricated bioinspired carbon nanotube network films(PAMAM@C-CNTF)have a high toughness of 45.97 MJ/m3.showing an increase of 42.%compared to neat *** importantly,the anti-impact performance of the films(e.g.,with a maximum specific energy absorption of 1.40 MJ/kg under 80-100 m/s projectile impact)is superior to that of conventional protective materials from steel and Kevlar fiber,and also exceeds that of any other reported carbon-based *** hierarchical energy dissipation mechanism was further revealed through experiment and *** functions including intelligent heating/anti-icing,ultraviolet protection,as well as electromagnetic interference shielding properties make these network films have great potential in practical multi-protection applications,especially under an extreme environment.

关键词： carbon nanotubes composites mechanical properties multi-function

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A three-dimensional co-continuous network structure polymer electrolyte with efficient ion transport channels enabling ultralong-life all solid-state lithium metal batteries

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Journal of Energy Chemistry 2024年第7期94卷 635-645页

作者： Meng wang Hu zhang Yewen {2. Ruiping {3. Huai Yang School of Chemical&Environmental Engineering China University of Mining and Technology(Beijing)Beijing 100083China beijing Advanced Innovation Center for Materials Genome Engineering&School of Materials Science and Engineering Peking UniversityBeijing 100871China

Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility,scalability,and interface compatibility with ***,a novel all-solid polymer electrolyte(PPLCE)was fabricated by the copolymer network of liquid crystalline monomers and poly(ethylene glycol)dimethacrylate(PEGDMA)acts as a structural frame,combined with poly(ethylene glycol)diglycidyl ether short chain interspersed serving as mobile ion transport *** preparaed PPLCEs exhibit excellent mechanical property and out-standing electrochemical performances,which is attributed to their unique three-dimensional cocontinuous structure,characterized by a cross-linked semi-interpenetrating network and an ionic liquid phase,resulting in a distinctive nanostructure with short-range order and long-range ***,the addition of PEGDMA is proved to be critical to the comprehensive performance of the PPLCEs,which effectively modulates the microscopic morphology of polymer networks and improves the mechanical properties as well as cycling stability of the solid *** used in a lithiumion symmetrical battery configuration,the 6 wt%-PPLCE exhibites super stability,sustaining operation for over 2.00 h at 3. C,with minimal and consistent overpotential of 50 *** resulting li|PPLCE|LFP solid-state battery demonstrates high discharge specific capacities of 160.9 and 12..1 mA h g^(-1)at current densities of 0.2.and 1 C,*** after more than 3.0 cycles at a current density of 0.2.C,it retaines an impressive 73.5%***,it displayes stable cycling for over 180 cycles at a high current density of *** super cycle stability may promote the application for ultralong-life all solid-state lithium metal batteries.

关键词： Solid-state electrolyte lithium-metal batteries liquid crystalline polymer Copolymer 3. co-continuous structure Long cycle stability

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Evolution of hollow nanosphere to microtube in the self-assembly of chiral dansyl derivatives and inversed circularly polarized luminescence

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Chinese Chemical Letters 2024年第7期35卷 285-290页

作者： Sifan Du Yuan wang Fulin wang Tianyu wang li {3. Minghua liu beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials Department of Chemistry and Chemical EngineeringSchool of Chemistry and Biological EngineeringUniversity of Science and Technology BeijingBeijing 100083China National Laboratory for Molecular Science(BNLMS) CAS Key Laboratory of ColloidInterface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

Here,we designed asymmetric(m DS)and symmetrical(d DS)chiral V-shaped molecules by linking one or two dansyl groups to trans-1,2.cyclohexane diamine and investigated the solvent-regulated structural transformation and inversed circularly polarized luminescence(CPL)in the *** increasing water volume fraction(fw)in the mixed solvent of water/acetonitrile,asymmetric mDS selfassembled into hollow nanospheres and microtubes,while solid nanospheres and solid microplates were corresponding to symmetric d *** this transformation process,the emission of m DS and d DS was changed from yellow-green to blue and cyan color,which was ascribed to twisted intramolecular charge transfer(TICT)and locally excited(LE)fluorescence of V-shaped DS *** conformation of N,Ndimethyl groups with respect to naphthalene ring also led to the transformation of *** tubular and platelike structures had stronger and reversed CPL signals in comparison with spheroidal *** chiral information of DS assembly could be effective transferred to achiral Nile red via co-assembly strategy,which endowed Nile red exhibiting inversed induced CPL signal regulated by water *** work provides a method for achieving a variety of self-assembled structures with adjustable chiroptical properties.

关键词： CPL inversion Hollow structure Self-assembly Dansyl Chirality transfer

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