检索结果-南通市图书馆

stability analyses of the mass abrasive projectile high-speed penetrating into a concrete target Part III: Terminal ballistic trajectory analyses

引用

Acta Mechanica sinica 2015年第4期31卷 558-569页

作者： h.Wu x.W.Chen q.Fang x.Z.Kong L.L.he Institute of systems Engineering China Academy of Engineering Physics state Key Laboratory for Disaster Prevention & Mitigation of Explosion & Impact PLA University of Science and Technology

During the high-speed penetration of projectiles into concrete targets （the impact velocity ranges from 1.0 to 1.5 km/s）, important factors such as the incident oblique and attacking angles, as well as the asymmetric abrasions of the projectile nose induced by the target-projectile interactions, may lead to obvious deviation of the terminal ballistic tra- jectory and reduction of the penetration efficiency. Based on the engineering model for the mass loss and nose-blunting of ogive-nosed projectiles established, by using the Differ- ential Area Force Law （DAFL） method and semi-empirical resistance function, a finite differential approach was pro- grammed （PEnTRA2D） for predicting the terminal ballistic trajectory of mass abrasive high-speed projectiles penetrating into concrete targets. It accounts for the free-surface effects on the drag force acting on the projectile, which are attributed to the oblique and attacking angles, as well as the asymmetric nose abrasion of the projectile. Its validation on the prediction of curvilinear trajectories of non-normal high-speed pene- trators into concrete targets is verified by comparison with available test data. Relevant parametric influential analyses show that the most influential factor for the stability of ter- minal ballistic trajectories is the attacking angle, followed by the oblique angle, the discrepancy of asymmetric nose abrasion, and the location of mass center of projectile. The terminal ballistic trajectory deviations are aggravated as the above four parameters increase.

关键词： Projectile Penetration Concrete Massabrasion Terminal ballistic trajectory

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Towards a unified nonlocal, peridynamics framework for the coarse-graining of molecular dynamics data with fractures

引用

Applied Mathematics and Mechanics(English Edition) 2023年第7期44卷 1125-1150页

作者： h.q.YoU x.xU Y.YU s.sILLInG M.D'ELIA J.FosTER Department of Mathematics Lehigh UniversityBethlehemPA 18015U.S.A Department of Petroleum and Geosystems Engineering The University of Texas at AustinTX 78712-1139U.S.A. Center for Computing Research Sandia National LaboratoriesCA 94551-0969U.S.A.

Molecular dynamics(MD)has served as a powerful tool for designing materials with reduced reliance on laboratory ***,the use of MD directly to treat the deformation and failure of materials at the mesoscale is still largely beyond *** this work,we propose a learning framework to extract a peridynamics model as a mesoscale continuum surrogate from MD simulated material fracture data ***,we develop a novel coarse-graining method,to automatically handle the material fracture and its corresponding discontinuities in the MD displacement data *** by the weighted essentially non-oscillatory(WEno)scheme,the key idea lies at an adaptive procedure to automatically choose the locally smoothest stencil,then reconstruct the coarse-grained material displacement field as the piecewise smooth solutions containing ***,based on the coarse-grained MD data,a two-phase optimizationbased learning approach is proposed to infer the optimal peridynamics model with damage *** the first phase,we identify the optimal nonlocal kernel function from the data sets without material damage to capture the material stiffness ***,in the second phase,the material damage criterion is learnt as a smoothed step function from the data with *** a result,a peridynamics surrogate is *** a continuum model,our peridynamics surrogate model can be employed in further prediction tasks with different grid resolutions from training,and hence allows for substantial reductions in computational cost compared with *** illustrate the efficacy of the proposed approach with several numerical tests for the dynamic crack propagation problem in a single-layer *** tests show that the proposed data-driven model is robust and generalizable,in the sense that it is capable of modeling the initialization and growth of fractures under discretization and loading settings that are different from the ones used during training.

关键词： nonlocal model machine learning homogenization peridynamics material fracture

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

EFFECTs oF DIFFEREnT FUnCTIonAL GRoUP-ConTAInInG oRGAnICs on MoRPhoLoGY-ConTRoLLED sYnThEsIs oF sILVER nAnoPARTICLEs AT RooM TEMPERATURE

引用

Acta Metallurgica sinica(English Letters) 2006年第5期19卷 362-370页

作者： A.L. Wang h.B. Yin M. Ren x.n. Cheng q.F. Zhou x.F. Zhang Faculty of Chemistry and Chemical Engineering Jiangsu University Zhenjiang 212013 China Department of Chemical Engineering Jiangsu Teachers University of Technology Changzhou 213001China

silver nanoparticles with average particles sizes ranging from 2 to 131nm were manipulatively synthesized starting from silver nitrate using different functional group-containing organic modifiers at room temperature. The effects of the organic modifiers on the morphology of the resulting silver nanoparticles were strongly dependent on the intrinsic properties of the functional groups and the reducibility of the reductant. numerous ether bonds （-0-）present in polyethylene glycol and Tween-80 were beneficial to the formation of silver nanoparticles with particle sizes of several nanometers in a narrow size distribution in both weak and strong reducing environments. Cetyltrimethylammonium bromide induced the formation of nanosized silver triangle plates in a weak reducing environment. The crystal growth of the silver nanoparticles with particle sizes of more than lonm was postulated through an adhesion process of small-sized particles followed by a subsequent coalescence process under the present reaction conditions.

关键词： silver nanoparticle nanostructure crystal growth TEM (transmissionelectron microscopy)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Amino Compounds in Poultry Litter,Litter-Amended Pasture soils and Grass shoots

引用

Pedosphere 2014年第2期24卷 178-185页

作者： Z.q.hE Z.n.sEnWo h.x.ZoU I.A.TAZIsonG D.A.MARTEns UsDA-ARs Southern Regional Research Center Department of Biological and Environmental sciences Alabama A&M University Department of Chemical and Biological Engineering the University of Maine UsDA-ARs Southwest Watershed Research Center

Amino compounds （ACs）, i.e., amino acids and amino sugars, are the major forms of organic nitrogen （n） in animal manure and soil. To increase our understanding on the effect of long-term poultry litter （PL） application on soil AC pools and turnover, in this study, we determined the contents of 21 ACs in 23 PL samples, i5 soil samples collected from 0-20, 20-40, and 40-60 cm layers of five pasture plots with 0, 5, 10, 15 and 20 years of PL applications, and 5 grass shoot samples grown on these pasture fields. The contents of 21 ACs were simultaneously determined by methanesulfonic acid hydrolysis/extraction and anion chromatography-pulsed amperometry. PL application increased soil total and individual AC contents with a distribution pattern similar to that of AC in PL. The highest AC-n concentrations were observed in the soils with 10- or 15-year PL applications, inconsistent with the order of annual application rates or eunmlative applied PL amounts. Application of PL increased the AC contents in grass shoots whereby the highest increase of most ACs was with the shoots from the fields that received PL for 5 years. These observations suggested that both freshly applied and residual PL had contributions to the soil AC-n, and that PL application also accelerated AC-n transformation in soil.

关键词： amino acids amino sugars broiler feed soil nitrogen

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Gradient structured Copper by Rotationally Accelerated shot Peening

引用

Journal of Materials science & Technology 2017年第7期33卷 758-761页

作者： x.Wang Y.s.Li q.Z.ang Y.h.Zhao Y.T.Zhu nano structural Materials Center School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing 210094 China school of Mechanical Engineering Nanjing University of Science and Technology Nanjing 210094 China Department of Materials science and Engineering North Carolina State University Raleigh NC 27695 USA

A new technology-rotationally accelerated shot peening（RAsP）, was developed to prepare gradient structured materials. By using centrifugal acceleration principle and large steel balls, the RAsP technology can produce much higher impact energy compared to conventional shot peening. As a proof-of-concept demonstration, the RAsP was utilized to refine the surface layer in pure copper（Cu） with an average grain size of 85 nm. The grain size increases largely from surface downwards the bulk, forming an800 ？m thick gradient-structured surface layer and consequently a micro-hardness gradient. The difference between the RAsP technology and other established techniques in preparing gradient structured materials is discussed. The RAsP technology exhibits a promoting future for large-scale manufacturing of gradient materials.

关键词： Microstructure Rotationally accelerated shot peening Gradient structure hardness Copper

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Desialylated Platelet Clearance in the Liver is a novel Mechanism of systemic Immunosuppression

引用

Research 2024年第3期2023卷 35-50页

作者： June Li Danielle Karakas Feng xue Yingyu Chen Guangheng Zhu Yeni h.Yucel sonya A.MacParland haibo Zhang John W.semple John Freedman qizhen shi heyu ni Department of Laboratory Medicine and Pathobiology University of TorontoTorontoONCanada Toronto Platelet Immunobiology Group TorontoONCanada Keenan Research Centre for Biomedical science of st.Michael's hospital TorontoONCanada Canadian Blood services Centre for Innovation TorontoONCanada Departments of Pediatrics Medical College of WisconsinMilwaukeeWIUSA Blood Research Institute Versiti WisconsinMilwaukeeWIUSA Departments of ophthalmology and Vision sciences Medicine University of TorontoTorontoONCanada Faculty of Engineering and Architectural science Ryerson UniversityTorontoONCanada Multi-organ Transplant Program Toronto General Hospital Research InstituteTorontoONCanada Department of Immunology University of TorontoTorontoONCanada Critical Care Medicine Department ofAnesthesiology and PainUniversity of TorontoTorontoONCanada Department of Physiology University of TorontoTorontoONCanada Department of Pharmacology University of TorontoTorontoONCanada. Division of hematology and Transfusion Medicine Lund UniversityLundSweden clinical Immunology and Transfusion Medicine Ofice of Medical ServicesRegion SkaneLundSweden Department of Medicine University of TorontoTorontoONCanada Children's Research Institute Children's WisconsinWauwatosaWIUSA Midwest Athletes Against Childhood Cancer Fund Research Center MilwaukeeWIUSA.

Platelets are small, versatile blood cells that are critical for hemostasis/thrombosis. Local platelet accumulation is a known contributor to proinflammation in various disease states. however, the anti-inflammatory/immunosuppressive potential of platelets has been poorly explored. here, we uncovered, unexpectedly, desialylated platelets (dPLTs) down-regulated immune responses against both platelet-associated and -independent antigen challenges. Utilizing multispectral photoacoustic tomography, we tracked dPLT trafficking to gut vasculature and an exclusive Kupffer cell-mediated dPLT clearance in the liver, a process that we identified to be synergistically dependent on platelet glycoprotein Ibα and hepatic Ashwell–Morell receptor. Mechanistically, Kupffer cell clearance of dPLT potentiated a systemic immunosuppressive state with increased anti-inflammatory cytokines and circulating CD4+ regulatory T cells, abolishable by Kupffer cell depletion. Last, in a clinically relevant model of hemophilia A, presensitization with dPLT attenuated anti-factor VIII antibody production after factor VIII ( infusion. As platelet desialylation commonly occurs in daily-aged and activated platelets, these findings open new avenues toward understanding immune homeostasis and potentiate the therapeutic potential of dPLT and engineered dPLT transfusions in controlling autoimmune and alloimmune diseases.

关键词： Platelet transfusion homeostasis

来源：

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

Enso impacts on litter stocks and water holding capacity in secondary forests in eastern Amazonia

引用

Journal of Forestry Research 2024年第1期35卷 83-89页

作者： Julia Isabella de Matos Rodrigues Walmer Bruno Rocha Martins Victor Pereira de oliveira Myriam suelen da silva Wanzerley hélio Brito dos santos Júnior Francisco de Assis oliveira Graduate Program in Forestry sciences Av.Presidente Tancredo Neves2501BelémPará66077-530Brazil Federal Rural University of Amazonia Av.Presidente Tancredo Neves2501BelémPará66077-530Brazil Federal Rural University of Amazonia Tv.Pau-AmareloCapitão PoçoPará68650-000Brazil national Institute of Amazonia Research Av.Constelação Cruzeiro do SulManausAmazonas 69060-062Brazil

Among the impacts of climate change,there is the intensification of phenomena such as the El niño south-ern oscillation(Enso)responsible for El niño and La niñ***,understanding their effects on the functional pro-cesses of forests is ***,this study evaluated the effects of Enso on litter stock and water holding capac-ity(WhC)in a successional forest in eastern *** occurred in periods with the most rainfall in El niño(2019)and least in La niña(2021)*** permanent plots were used to sample *** effects were evident for WhC,higher during El niñ***,this influence was not clear for litter,as only in the rainy season effects were *** was a positive correlation of WhC with precipitation and humidity,while litter stocks were negatively correlated with temperature and wind *** the subject of this study requires long-term assessments,preliminary results suggests that,depending on the intensity of Enso,forest functional processes can be strongly impacted and *** conclusion reinforces warnings by the scientific community about the impacts of climate change on the maintenance of litter stocks,decomposition and,consequently,the biogeochemical cycle and essential ecosystem services for the maintenance of Amazonia *** need to develop long-term research to understand the effects of climatic change on litter stocks and water holding capacity is highlighted,especially in Amazonia.

关键词： seasonality Climate change succession ecosystem Biogeochemical cycle Amazonia biodiversity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ferroelectricity Induced by oxygen Vacancies in Rhombohedral Zro_(2) Thin Films

引用

Energy & Environmental Materials 2024年第1期7卷 229-237页

作者： Veniero Lenzi José P.B.silva Břetislav Šmíd Vladimir Matoín Cosmin M.Istrate Corneliu Ghica Judith L.MacManus-Driscoll Luís Marques Physics Center of Minho and Porto Universities(CF-UM-UP) University of MinhoCampus de Gualtar 4710-057Braga Portugal Laboratory of Physics for Materials and Emergent Technologies LapMETUniversity of Minho4710-057Braga Portugal Department of surface and Plasma science Faculty of Mathematics and PhysicsCharles UniversityV Holešovičkách 218000Prague 8 Czech Republic national Institute of Materials Physics 105 bis Atomistilor 077125Magurele Romania Department of Materials science and Metallurgy 27 Charles Babbage Rd.Cambridge CB3 OFSUK

Rhombohedral phase hf_(x)Zr_(1.x)o_(2)(hZo,x from 0 to 1)films are promising for achieving robust ferroelectric polarization without the need for an initial wake-up pre-cycling,as is normally the case for the more commonly studied orthorhombic ***,a large spontaneous polarization observed in rhombohedral films is not fully understood,and there are also large discrepancies between experimental and theoretical *** this work,in rhombohedral Zro_(2)thin films,we show that oxygen vacancies are not only a key factor for stabilizing the phase,but they are also a source of ferroelectric polarization in the *** is shown experimentally through the investigation of the structural properties,chemical composition and the ferroelectric properties of the films before and after an annealing at moderate temperature(400℃)in an oxygen environment to reduce the V_(o)concentration *** experimental work is supported by density functional theory(DFT)calculations which show that the rhombohedral phase is the most stable one in highly oxygen defective Zro_(2)*** DFT calculations also show that V_(o)contribute to the ferroelectric *** findings reveal the importance of V_(o)for stabilizing rhombohedral Zro_(2)thin films with superior ferroelectric properties.

关键词： charged defects ferroelectric polarization rhombohedral phase stability zirconia

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Embedding laser-generated CdTe nanocrystals into ultrathin ZnIn_(2)s_(4) nanosheets with sulfur vacancies for boosted photocatalytic h_(2) evolution

引用

Journal of Materials science & Technology 2023年第35期166卷 113-122页

作者： Z.G.Tai G.T.sun x.h.Zhang x.B.Yang T.Wang Z.Y.Fang q.Ye L.C.Jia h.q.Wang state Key Laboratory of solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of northwestern Polytechnical University in shenzhen Shenzhen 518063China school of Materials science and Engineering Shaanxi Normal UniversityXi’an 710119China

To suppress the inner charge recombination and inject vast electrons,CdTe nanocrystals are embedded into ultrathin ZnIn_(2)s_(4) nanosheets to construct ZnIn_(2)s_(4)/CdTe heterostructures,where the nanocrystals are generated by a laser irradiation *** optimal ZnIn_(2)s_(4)/CdTe heterojunction exhibits an excellent catalytic activity of 24.3 mmol/h/g,which is relatively high among the ZnIn_(2)s_(4)-based photocatalysts with-out noble *** enhancement is ascribed to a win-win mechanism of nanoscale heterojunctions and sulfur *** strong electron coupling effect,which is verified by density functional the-ory(DFT)calculations,impels the photo-generated electrons transfer from CdTe to ZnIn_(2)s_(4),boosting the charge ***,the sulfur vacancies existing in ZnIn_(2)s_(4) can capture photoelectrons and act as active sites,facilitating the h_(2) generation *** addition,the ZnIn_(2)s_(4) base and the ZnIn_(2)s_(4)/CdTe heterojunction also possess an evident photothermal effect and renewable cycle phenomena,enhancing the photocatalytic *** research provides new insights into the regulation of charge transfer through embedding nanocrystals.

关键词： Photocatalysis hydrogen evolution Laser irradiation heterostructure sulfur vacancies

来源：

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

Effect of solute atom concentration and precipitates on serrated flow in Mg-3nd-Zn alloy

引用

Journal of Materials science & Technology 2018年第7期34卷 1236-1242页

作者： W.h.Wang D.Wu R.s.Chen x.n.Zhang state Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University The Group of Magnesium Alloys and Their Applications Institute of Metal Research Chinese Academy of Sciences

Influence of solute atom concentration and precipitates on serrated flow, i.e., Portevin-Le Chatelier effect, was studied in Mg-3nd-Zn alloy by tensile test at 250℃ with a strain rate of l x 10^-3 s^-1 Microstructure and tensile property of the Mg-3nd-Zn alloy in solution and aging conditions were also investigated. Results indicate that the serrated flow was weakened with aging time, and geometry of the serrations changed from sharp to rounded corner. Through analyzing the mechanism of the interactions between dislocations and solute atoms, it was identified that the precipitates did not only weaken the serrated flow due to the decrease in the concentration of solute atom, but also regulate the serration type by restraining the movement of dislocations during high temperature deformation.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials science ＆ Technology.

关键词： Magnesium alloy serrated flow Precipitate heat treatment Deformation behavior

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：