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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.,2.& wang jianguo31. institute of mechanics, 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 institute of mechanics Chinese Academy of Sciences Beijing 100080 China Graduate 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 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 30% 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.& wang Yuannian1 1. institute of mechanics, Chinese Academy of Sciences, Beijing 100080, china 2. Graduate School, Chinese Academy of Sciences, Beijing 100060, china institute of mechanics Chinese Academy of Sciences Beijing 100080 China Graduate School Chinese Academy of Sciences Beijing 100060 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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light-driven sextuple theranostics:nanomedicine involving second near-infrared AIE-active Ir(Ⅲ)complex for prominent cancer treatment

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Science china Chemistry 2024年第7期67卷 2314-2324页

作者： Xue liu Jiangao li Fei {2. Dingyuan Yan lei wang Dong wang Ben Zhong Tang Center for AIE Research Shenzhen Key Laboratory of Polymer Science and TechnologyGuangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Material Science and EngineeringShenzhen UniversityShenzhen 518060China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China School of Science and Engineering Shenzhen Institute of Aggregate Science and TechnologyThe Chinese University of Hong KongShenzhen(CUHK-Shenzhen)Shenzhen 518172China

light-driven cancer theranostics has shown inexhaustible and vigorous vitality by virtue of its high efficacy,prominent controllability and *** of an all-round theranostic material simultaneously affording both multimodal diagnosis imaging and synergistic phototherapy would be an appealing yet significantly challenging ***,a novel nanomedicine Ir@PPEG-MeEPO was ingeniously constructed by integrating beforehand1O2.charged amphiphilic polymer and well-tailored Ir(Ⅲ)complex IrDPTP,which was featured by second near-infrared(NIR-Ⅱ)aggregation-induced emission(AIE)tendency,efficient reactive oxygen species(ROS)generation,good photothermal conversion efficiency and high-performance hydrogen gas *** the best of our knowledge,IrDPTP held the longest emission wavelength among all reported AIE Ir(Ⅲ)***,Ir@PPEG-MeEPO was capable of controllably releasing ROS via triggered photothermal effect upon NIR irradiation,making it well-adapted to hypoxic environment of *** distinctive characteristics of Ir@PPEG-MeEPO endowed it with unprecedented performance on sextuple theranostics comprised of NIR-Ⅱfluorescence-photoacoustic-photothermal trimodal imaging and photodynamic-photothermal-hydrogen trimodal therapy,witnessed by the precise tumor diagnosis and complete tumor *** study would open up new perspectives for the exploration of superior nanomedicine for practical cancer theranostics.

关键词： aggregation-induced emission NIR-II emission cancer theranostics multimodal diagnosis imaging multimodal therapy

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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 &{2. 1.institute of mechanics, Chinese Academy of Sciences, Beijing 100080, china 2.Graduate School, Chinese Academy of Sciences, Beijing 100060, china institute of mechanics Chinese Academy of Sciences Beijing China Graduate 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-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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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. lei 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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High donor-number and low content electrolyte additive for stabilizing zinc metal anode

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Journal of Energy Chemistry 2024年第8期95卷 626-635,I0014页

作者： Yuxin Gong Ruifan lin Bo wang Huaizheng Ren {2. wang Han {2. Jianxin wang Deyu li Yueping Xiong Dianlong wang Huakun liu Shixue Dou MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage State Key Laboratory of Urban Water Resource and EnvironmentSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001HeilongjiangChina Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) College of ChemistryNankai UniversityTianjin 300071China institute of Energy Material Science University of Shanghai for Science and TechnologyShanghai 200093China

The aqueous zinc ion batteries(AZIBs)are thought as promising competitors for electrochemical energy storage,though their wide application is curbed by the uncontrollable dendrite growth and gas evolution side ***,to stabilize both zinc anodes and water molecules,we developed a modified electrolyte by adding a trace amount of N,N-diethylformanmide(DEF)into the ZnSO_(4)electrolyte for the first time in zinc ion *** effectiveness of DEF is predicted by the comparison of donor number and its preferential adsorption behavior on the zinc anode is further demonstrated by several spectroscopy characterizations,electrochemical methods,and molecular dynamics *** modified electrolyte with 5%*** content can ensure a stable cycling life longer than 3400 h of Zn‖Zn symmetric cells and an ultra-reversible Zn stripping/plating process with a high coulombic efficiency of 99.7%.The Zn‖VO_(2.full cell maintains a capacity retention of 83.5%and a 104 mA h g^(-1)mass capacity after *** work provides insights into the role of interfacial adsorption behavior and the donor number of additive molecules in designing low-content and effective aqueous electrolytes.

关键词： Aqueous zinc ion batteries Zinc anode Electrolyte additives Donor number Zinc dendrites

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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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Fast-Charging Sodium-Ion Batteries Enabled by Molecular-Level Designed Nitrogen and Phosphorus Codoped Mesoporous Soft Carbon

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Research 2024年第2期2023卷 329-337页

作者： lei liu Zhuzhu Du Jiaqi {2. Hongfang Du Sheng Wu Mengjun li Yixuan zhang Jinmeng Sun Zhipeng Sun Wei Ai Frontiers Science Center for Flexible Electronics(FSCFE)and Shaanxi institute of Flexible Electronics(SIFE) Northwestern Polytechnical University(NPU)127 West Youyi RoadXi'an 710072China Fujian Cross Strait institute of Flexible Electronics(Future Technologies) Fujian Normal UniversityFuzhou 350117China School of Materials and Energy Guangdong University of TechnologyGuangzhou510006 GuangdongChina

Soft carbons have attracted extensive interests as competitive anodes for fast-charging sodium-ion batteries(SIBs);however,the high-rate performance is still restricted by their large ion migration barriers and sluggish reaction ***,we show a molecular design approach toward the fabrication of nitrogen and phosphorus codoped mesoporous soft carbon(NPSC).The key to this strategy lies in the chemical cross-linking reaction between polyphosphoric acid and p-phenylenediamine,associated with pyrolysis induced in-situ self-activation that creates mesoporous structures and rich heteroatoms within the carbon *** to the enlarged interlayer spacing,reduced ion diffusion length,and plentiful active sites,the obtained NPSC delivers a superb rate capacity of 2.5 mAh g-1 at 10 A g-1 and an ultralong cycle life of 4,700 cycles at 5 A g^(-1).Remarkably,the full cell shows 99%capacity retention during 100 continuous cycles,and maximum energy and power densities of 191 Wh kg^(-1)and 9.2.kW kg^(-1),*** believe that such a synthetic protocol could pave a novel venue to develop soft carbons with unique properties for advanced SIBs.

关键词： kinetics carbons linking

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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 zhang 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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Investigating the effect of volatility on the hygroscopicities of acetate nanoparticle aerosols by surface plasmon resonance microscopy

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Journal of Environmental Sciences 2024年第4期138卷 167-178页

作者： Bo Yang Zhibo Xie jianguo liu Huaqiao Gui Jiaoshi {2. Xiuli Wei Zetao Fan Douguo {2. Key Laboratory of Environmental Optics and Technology Anhui Institute of Optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of china Hefei 230026China CAS Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Advanced Laser Technology Laboratory of Anhui Province Department of Optics and Optical EngineeringUniversity of Science and Technology of ChinaHefei 230026China

Under high relative humidity(RH)conditions,the release of volatile components(such as acetate)has a significant impact on the aerosol *** this work,one surface plasmon resonance microscopy(SPRM)measurement system was introduced to determine the hygroscopic growth factors(GFs)of three acetate aerosols separately or mixed with glucose at different *** Ca(CH_(3)COO)_(2. or Mg(CH_(3)COO)_(2. aerosols,the hygroscopic growth trend of each time was lower than that of the previous time in three cyclic humidification from 70% RH to 90% RH,which may be due to the volatility of acetic acid leading to the formation of insoluble hydroxide(Ca(OH)_(2. or Mg(OH)_(2.)under high RH *** the third calculated GF(using the Zdanovskii-Stokes-Robinson method)for Ca(CH_(3)COO)_(2. or Mg(CH_(3)COO)_(2. in bicomponent aerosols with 1:1 mass ratio were 3.2.% or 5.33% lower than that of the first calculated GF at 90% *** calculated results also showed that the hygroscopicity change of bicomponent aerosol was negatively correlated with glucose content,especially when the mass ratio of Mg(CH_(3)COO)_(2. to glucose was 1:2.the GF at 90% RH only decreased by4.67% after three cyclic *** coupled plasma atomic emission spectrum(ICP-AES)based measurements also indicated that the changes of Mg^(2.)concentration in bicomponent was lower than that of the *** results of this study reveal thatduring the efflorescence transitions of atmospheric nanoparticles,the organic acids diffusion rate may be inhibited by the coating effect of neutral organic components,and the particles aging cycle will be prolonged.

关键词： Hygroscopic growth Volatility Acetate aerosols Nanoparticle aerosol Surface plasmon resonance

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