检索结果-南通市图书馆

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

作者： zhang lei1,{1.,{2.,2.& wang yuannian1 1. institute of mechanics, chinese academy of sciences, Beijing 100080, china 2. Graduate School, chinese academy of sciences, Beijing 1.0060, china institute of {1. Chinese Academy of Sciences Beijing 100080 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.

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

在线全文

学校读者我要写书评

暂无评论

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

作者： liU Bingshan1, li shihai1, zhang lei1,{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 {1. 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.

Stochastic structural model of rock and soil aggregates by continuum-based discrete element method

在线全文

学校读者我要写书评

暂无评论

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

作者： wang yuannian1, ZHAO Manhong1, li {2. & J.G. wang2.. institute of mechanics, chinese academy of sciences, Beijing 100080, china 2. Tropical Marine Science institute, National University of Singapore, 10 Kent Ridge Crescent, Singapore 1192.0 institute of {1. Chinese Academy of Sciences

This paper first presents a stochastic structural model to describe the random geometrical features of rock and soil aggregates. The stochastic structural model uses mixture ratio, rock size and rock shape to construct the microstructures of aggregates, and introduces two types of structural elements (block element and jointed element) and three types of material elements (rock element, soil element, and weaker jointed element) for this microstructure. Then, continuum-based discrete element method is used to study the deformation and failure mechanism of rock and soil aggregate through a series of loading tests. It is found that the stress-strain curve of rock and soil aggregates is nonlinear, and the failure is usually initialized from weaker jointed elements. Finally, some factors such as mixture ratio, rock size and rock shape are studied in detail. The numerical results are in good agreement with in situ test. Therefore, current model is effective for simulating the mechanical behaviors of rock and soil aggregates.

关键词： CDEM, rock and soil aggregate, mixture ratio.

Integrated biomarker response to assess toxic impacts of iron and manganese on deep-sea mussel Gigantidas platifrons under a deep-sea mining activity scenario

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and limnology 2024年第2期42卷 522-532页

作者： li ZHOU Mengna li Zhaoshan ZHONG Minxiao wang Hao CHEN Chao lian Hao wang Huan zhang lei CAO Chaolun li Center of Deep Sea Research Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laoshan Laboratory Qingdao 266237China South china Sea {1. of Oceanology Chinese Academy of SciencesGuangzhou 510301China CAS Key Laboratory of Marine Ecology and Environmental sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of chinese academy of sciences Beijing 100049China

Deep-sea mining activities can potentially release metals,which pose a toxicological threat to deep-sea ***,due to the remoteness and inaccessibility of the deep-sea biosphere,there is insufficient knowledge about the impact of metal exposure on its *** this study,deep-sea mussel Gigantidas platifrons,a commonly used deep-sea toxicology model organism,was exposed to manganese(1.0,1.00μg/L)or iron(500,5000μg/L)for 7 d,*** and iron were chosen for their high levels of occurrence within deep-sea *** accumulation and a battery of biochemical biomarkers related to antioxidative stress in superoxide dismutase(SOD),catalase(CAT),malondialdehyde(MDA);immune function in alkaline phosphatase(AKP),acid phosphatase(ACP);and energy metabolism in pyruvate kinase(PK)and hexokinase(HK)were assessed in mussel *** showed that deep-sea mussel *** exhibited a high capacity to accumulate Mn/*** addition,most tested biochemical parameters were altered by metal exposure,demonstrating that metals could induce oxidative stress,suppress the immune system,and affect energy metabolism of deep-sea *** integrated biomarker response(IBR)approach indicated that the exposure to Mn/Fe had a negative impact on deep-sea mussels,and Mn demonstrated a more harmful impact on deep-sea mussels than ***,SOD and CAT biomarkers had the greatest impact on IBR values in Mn treatments,while ACP and HK were most influential for the low-and high-dose Fe groups,*** study represents the first application of the IBR approach to evaluate the toxicity of metals on deep-sea fauna and serves as a crucial framework for risk assessment of deep-sea mining-associated metal exposure.

关键词： mussel metal deep-sea mining biomarker environmental monitoring

Coupling effect of cement-stabilization and biopolymer-modification on the mechanical behavior of dredged sediment

在线全文

学校读者我要写书评

暂无评论

Journal of Rock mechanics and Geotechnical Engineering 2024年第8期16卷 3284-3298页

作者： lei Lang Jiangshan {1. Xiao Huang Ping wang Wei {2. State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China Hubei Provincial Key Laboratory of Contaminated Sludge and Soil Science and Engineering Wuhan430071China University of chinese academy of sciences Beijing100049China

Nowadays,biopolymer stabilization as a promising eco-friendly approach in soft ground improvement has attracted wide ***,the feasibility of using biopolymer as a green additive of cementstabilized dredged sediment(CDS)with high water content is still *** this study,guar gum(GG)and xanthan gum(XG)were adopted as typical biopolymers,and a series of unconfined compressive strength(UCS),splitting tensile strength(STS)and scanning electron microscopy(SEM)tests were performed to evaluate the mechanical and microstructural properties of XG-and GG-modified CDSs considering several factors including biopolymer modification,binderesoil ratio and wateresolid ***,the micro-mechanisms revealing the evolutions of mechanical properties of biopolymermodified CDS were *** results indicate that the addition of XG can effectively improve the strength of CDS,while the GG has a side *** XG content of 9%was recommended,which can improve the 7 d-and 2. d-UCSs by 1.6%and 51.8%,together with the 7 d-and 2. d-STSs by 1.8.3%and 42.2.,*** the binderesoil ratio or decreasing the wateresolid ratio significantly improved the strength gaining but aggravated the brittleness characteristics of *** XG to CDS contributed to the formation of microstructure with more compactness and higher cementation degrees of ordinary Portland cement(OPC)-XG-stabilized DS(CXDS).The micro-mechanism models revealing the interactions of multiple media including OPC cementation,biopolymer film bonding and bridging effects inside CXDS were *** key findings confirm the feasibility of XG modification as a green and high-efficiency mean for improving the mechanical properties of CDS.

关键词： Dredged sediment(DS) Stabilization Biopolymer modification Mechanical properties Micro-mechanism

Pore Formation Mechanism in W-C Hard Coatings Using Directed Energy Deposition on Tungsten Alloy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 89-101页

作者： Xinrui zhang Weijie Fu Chen {1. Zhenglong {2. Haoran Sun Xudong li State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin150001China

Porosity is a common phenomenon and can significantly hinder the quality of the ***,the pore formation mechanism and the characteristics of the single tracks of the W-C coating using directed energy deposition(DED)are systematically *** forming quality of the tracks,the distribution of the pores,and the elemental distribution near the pores are analyzed by the observations of the cross-sections of the *** temperature field of the melt pool is discussed comprehensively to reveal the pore formation *** results confirm that Ni and Co evaporated during the DED process due to the high temperature of the melt *** were continuously produced adjacent to the fusion line when the melt pool was about to solidify since the temperature at the solidification front was higher than the boiling point of *** vaporization area at the fusion line was proposed,where Ni could also evaporate at the time the melt pool started to *** relationship between the solidification rate,the size of the vaporization area and the DED parameters(laser power and scanning speed)was established to discuss the causes of severe pores above the fusion *** work contains a practical guide to reduce or eliminate the porosity in the coating preparation process on the surface of the tungsten alloy.

关键词： Directed energy deposition(DED)process Tungsten alloy W-C coating Pores Binder phase

Progress and Outlook of Carbon-supported Single-atom Electrocatalyst for Oxygen Reduction Reaction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in chinese Universities 2024年第3期40卷 462-474页

作者： wang Chengbin {1. Ping CHEN Dehong zhang Ruiyong wang lei ZONG {1.ngbo College of Chemistry and Molecular Engineering Qingdao University of Science and TechnologyQingdao 266042P.R.China College of Materials Science and Engineering Qingdao University of Science and TechnologyQingdao 266042P.R.China Key Laboratory of Marine Environmental Corrosion and Bio-fouling Institute of OceanologyChinese Academy of SciencesQingdao 266071P.R.China

Single-atom catalysts (SACs) have garnered extensive attention in the field of catalysis due to their exceptional inherent reaction activity, optimal utilization of metal atoms, etc. Controlled synthesis plays a crucial role in elucidating the structure-activity relationship of SACs. This paper reviews various synthetic strategies for SACs, encompassing defect engineering, metal-organic frameworks (MOFs) pyrolysis, and ion exchange. With specific examples, the significance of constructing catalysts at the atomic level is discussed, aiming to comprehensively understand the synthetic strategies of SACs. Finally, it addresses the challenges and prospects associated with controlled synthesis techniques for SACs as well as their future applications.

关键词： Single-atom catalyst Synthetic strategy Carbon support Oxygen reduction reaction

Graphene Nanoribbons Enhancing the Electronic Conductivity and Ionic Diffusion of Graphene Electrodes for High-Performance Microsupercapacitors

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2024年第4期7卷 285-294页

作者： Yan zhang Huandi zhang Xiaoxiao {2. Xiaowei Shi Zehua Zhao Yaling {2. Jiamei liu Cheng Tang Guolong {2. lei li State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and Engineering Xi'an Jiaotong University Center for Materials Chemistry Frontier Institute of Science and TechnologyXi'an Jiaotong University Instrument Analysis Center of Xi'an Jiaotong University Xi'an Jiaotong University

The electrochemical performance of microsupercapacitors with graphene electrodes is reduced by the issue of graphene sheets aggregation,which limits electrolyte ions penetration into *** the space between graphene sheets in electrodes facilitates the electrolyte ions penetration,but sacrifices its electronic conductivity which also influences the charge storage ability.

关键词： areal energy density graphene graphene nanoribbons microsupercapacitors structure engineering

light-driven sextuple theranostics:nanomedicine involving second near-infrared AIE-active Ir(Ⅲ)complex for prominent cancer treatment

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 Chemistry 2024年第7期67卷 2314-2324页

作者： Xue liu Jiangao li Fei zhang Dingyuan Yan lei {2. Dong {2. 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 beforehand1.2.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

Langasite-based SAW high-temperature vibration sensor with temperature decoupling

在线全文

学校读者我要写书评

暂无评论

Science china(Technological {1.) 2024年第6期67卷 1946-1956页

作者： zhang Juan CHENG WenHua {1. Hao zhang lei li XiangRong MA HongShuai PANG JunQi TAN Qiulin State Key Laboratory of Dynamic Measurement Technology North University of ChinaTaiyuan030051China Department of Mechanical Engineering Taiyuan Institute of TechnologyTaiyuan030008China

Monitoring high-temperature vibrations is critical in aerospace engineering,industrial manufacturing,and energy production,where harsh conditions necessitate robust vibration sensors for detecting anomalous ***,the accuracy of such sensors is often compromised by crosstalk between temperature and vibration *** study introduces a high-temperature vibration sensor based on langasite(LGS)surface acoustic wave(SAW)technology,designed to withstand temperatures up to 500℃.The sensor demonstrates high sensitivity,ranging from 1.0}54 kHz/g at 2.℃ to 1..63 k Hz/g at 500℃.A comprehensive mechanical and electrical coupling model for the SAW vibration sensor was developed by integrating theoretical equations with numerical simulations to optimize the sensor's ***,a novel decoupling algorithm for temperature and vibration was established,achieving thermomechanical decoupling with precise vibration *** results indicated a maximum relative deviation of 4.67%for the *** conclusion,the proposed LGS SAW vibration sensor emerges as a promising solution for the accurate detection of multiple parameters in high-temperature vibration monitoring.

关键词： high temperature langasite(LGS) surface acoustic wave(SAW) piezoelectric vibration sensor temperature decoupling