检索结果-南通市图书馆

McSE planning a Windows Server 2003 network infrastructure (exam 70-293)

在线全文

学校读者我要写书评

暂无评论

Fracture initiation and propagation in intact rock—A review

丛书名： Mike Meyers' certification passport

2003年

作者： Mccain chris Brown martin c

来源：畅想之星图书光盘版（南... 评论

在线全文

畅想之星图书光盘版（南通市图书馆镜像）

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2014年第4期6卷 287-300页

作者： E.Hoek c.D.martin West Vancouver British Columbia V7V 0B3 Canada Department of civil & Environmental Engineering University of Alberta Edmonton Alberta T6G 2W2 Canada

The initiation and propagation of failure in intact rock are a matter of fundamental importance in rock engineering. At low confining pressures, tensile fracturing initiates in samples at 40%-60% of the uniaxial compressive strength and as loading continues, and these tensile fractures increase in density, ultimately coalescing and leading to strain localization and macro-scale shear failure of the samples. The Griffith theory of brittle failure provides a simplified model and a useful basis for discussion of this process. The Hoek-Brown failure criterion provides an acceptable estimate of the peak strength for shear failure but a cutoff has been added for tensile conditions. However, neither of these criteria adequately explains the progressive coalition of tensile cracks and the final shearing of the specimens at higher confining stresses. Grain-based numerical models, in which the grain size distributions as well as the physical properties of the component grains of the rock are incorporated, have proved to be very useful in studying these more complex fracture processes.

关键词： Tensile failure crack propagation Griffith theory Hoek-Brown criterion Tension cutoff crack coalescence Numerical models

Investigation of the compressible Flow through the Tip-Section Turbine Blade cascade with Supersonic Inlet

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2016年第2期25卷 138-144页

作者： martin Luxa Jaromír Príhoda David Simurda Petr Straka Jaroslav Synác Institute of Thermomechanics AS cR v.v.i. Dolejskova 1402/5 18200 Prague Czech Republic Aerospace Research and Test Establishment Plc Beranovych 130 19905 Prague Czech Republic Doosan Skoda Power co. Ltd. Tylova 1/57 30128 Pilsen Czech Republic

The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.

关键词：可压缩流动涡轮叶栅超声速进气道光学实验湍流模型数值研究叶栅流场配置文件

肺MRI应用弹性配准的方法评估系统性硬化病人的肺纤维化情况

在线全文

学校读者我要写书评

暂无评论

国际医学放射学杂志 2019年第4期 483-484页

作者：吴酥 G.chassagnon c.martin R.Marini M.Vakalopolou A.Régent L.Mouthon Department of Radiology Groupe Hospitalier Cochin H?tel Dieu AP-HP Université Paris Descartes

摘要目前的影像方法对纤维化引起的肺功能的改变不敏感。具有超短回波时间的MRI可用于肺实质及肺部运动的成像。目的评价系统性硬化(SSc)病人应用吸气-呼气相

关键词：系统性硬化病肺纤维化 MRI 弹性配准方法评估

A novel non-invasive method for predicting bone mineral density and fracture risk using demographic and anthropometric measures

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Sports Medicine and Health Science 2023年第4期5卷 308-313页

作者： Justin Aflatooni Steven martin Adib Edilbi Pranav Gadangi William Singer Robert Loving Shreya Domakonda Nandini Solanki Patrick c.Mcculloch Bradley Lambert Orthopedic Biomechanics Research Laboratory Department of Orthopedics and Sports MedicineHouston Methodist HospitalHoustonTXUSA Sydney&J.L.Huffines Institute for Sports Medicine&Human Performance Department of Health and KinesiologyTexas A&M UniversityCollege StationTXUSA

Fractures are costly to treat and can significantly increase *** dual-energy x-ray absorptiometry(DEXA)is used to screen at risk people with low bone mineral density(BMD),not all areas have access to *** sought to create a readily accessible,inexpensive,high-throughput prediction tool for BMD that may identify people at risk of fracture for further *** and demographic data were collected from 492 volunteers(♂275,♀217;[44-20]years;Body Mass Index(BMI)=[27.6-6.0]kg/m^(2))in addition to total body bone mineral content(BMc,kg)and BMD measurements of the spine,pelvis,arms,legs and total ***-linear-regression with step-wise removal was used to develop a two-step prediction model for BMc followed by *** selection was determined by the highest adjusted R2,lowest error of estimate,and lowest level of variance inflation(α=0.05).Height(HTcm),age(years),sex^(m=1,f=0),%body fat(%fat),fat free mass(FFMkg),fat mass(FMkg),leg length(LLcm),shoulder width(SHWDTHcm),trunk length(TRNKLcm),and pelvis width(PWDTHcm)were observed to be significant predictors in the following two-step model(pc(kg)=(0.0063×HT)+(-0.0024×AGE)+(0.1712×SEX^(m=1,f=0))+(0.0314×FFM)+(0.001×FM)+(0.0089×SHWDTH)+(-0.0145×TRNKL)+(-0.0278×PWDTH)-0.5073;R^(2)=0.819,***2:Total body BMD(g/cm^(2))=(-0.0028×HT)+(-0.0437×SEX^(m=1,f=0))+(0.0008×%FAT)+(0.2970×BMc)+(-0.0023×LL)+(0.0023×SHWDTH)+(-0.0025×TRNKL)+(-0.0113×PWDTH)+1.379;R^(2)=0.89,*** models were also developed to predict leg,arm,spine,and pelvis BMD(R^(2)=0.796-0.864,pcture who would benefit from further evaluation,especially in the resource or time restricted setting.

关键词： Bone Bone density Fracture Fracture risk Assessment Osteoporosis

A numerical investigation into key factors controlling hard rock excavation via electropulse stimulation

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

Journal of Rock Mechanics and Geotechnical Engineering 2020年第4期12卷 793-801页

作者： Daniel Vogler Stuart DcWalsh martin OSaar Geothermal Energy and Geofluids Institute of GeophysicsETH ZurichZurichSwitzerland Department of civil Engineering Monash UniversityMelbourneAustralia Department of Earth and Environmental Sciences University of MinnesotaMinneapolisUSA

Electropulse stimulation provides an energy-efficient means of excavating hard rocks through repeated application of high voltage pulses to the rock *** such,it has the potential to confer significant advantages to mining and drilling operations for mineral and energy ***,before these benefits can be realized,a better understanding of these processes is required to improve their deployment in the *** this paper,we employ a recently developed model of the grain-scale processes involved in electropulse stimulation to examine excavation of hard rock under realistic operating *** that end,we investigate the maximum applied voltage within ranges of 120e600 kV,to observe the onset of rock *** further study the effect of grain size on rock breakage,by comparing fine(granodiorite)and coarse grained(granite)***,the pore fluid salinity is investigated,since the electric conductivity of the pore fluid is shown to be a governing factor for the electrical conductivity of the modeled *** study demonstrates that all investigated factors are crucial to the efficiency of rock fragmentation by electropulsing.

关键词： Electropulse stimulation High voltage breakdown Numerical modeling Drilling Thermo-mechanics

Micro-mechanical deformation behavior of cocrFeMnNi high-entropy alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第5期100卷 237-245页

作者： Kaiju Lu Ankur chauhan Dimitri Litvinov Aditya Srinivasan Tirunilai Jens Freudenberger Alexander Kauffmann martin Heilmaier Jarir Aktaa Institute for Applied Materials Karlsruhe Institute of Technology(KIT)Hermann-von-Helmholtz-Platz 176344 Eggenstein LeopoldshafenGermany Institute for Applied Materials Karlsruhe Institute of Technology(KIT)Engelbert-Arnold-Strasse 476131 KarlsruheGermany Leibniz Institute for Solid State and Materials Research Dresden(IFW Dresden) Helmholtzstr.20D-01069 DresdenGermany Institute of Materials Science Technische Universität Bergakademie FreibergGustav-Zeuner-Str.509599 FreibergGermany

In the present study,the micro-mechanical behavior of co crFeMnNi high-entropy alloy was investigated using an in-house micro-tensile setup at room temperature and 550℃ at different strain *** properties are compared with those obtained using a commercial macro-tensile setup to check a potential sample size *** show that mechanical properties such as yield strength,ultimate tensile strength and uniform elongation are independent of the sample ***,the total elongation-to-failure of micro-samples is found to be lower than those of *** from this,the material exhibits serrated plastic flow,which is strain rate dependent in terms of the onset strain and shape of serrations at 550℃.Furthermore,transmission electron microscopy investigations were performed to correlate the occurrence of serrations to the observed distinct dislocation *** results provide direct evidence that dislocations are curved and hence effectively pinned and unpinned at the lowest applied strain rate,which might be responsible for the occurrence of serrated plastic flow.

关键词： High-entropy alloy Mechanical properties Micro-tensile Deformation mechanism Serration

Resistance to the Whitefly Aleurotrachelus socialis(Hemiptera:Aleyrodidae) and SSR Marker Identification in Advanced Populations of the Hybrid Manihot esculenta *** flabellifolia

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2013年第12期12卷 2217-2228页

作者： Arturo carabalí James Montoya-Lerma Anthony c Belloti martin Fregene Gerardo Gallego Deparment of Biology Universidad del Valle International center of Tropical Agriculture (cIAT)

Genes resistant to Aleurotrachelus socialis were transferred to the F 1 from the interspecific hybrid wild species of Manihot flabellifolia to *** and two advanced generations of backcrosses（Bc 1 and Bc 2）.We characterized the resistance of *** transferred to Bc 2 parents（cW67-160,cW67-130,cW67-44）,MTAI-8（Bc 1）,resistant（cMB9B-73） and susceptible（cMB9B-104） genotypes from contrasting pools,and resistant（MEcu-72） and susceptible（cMc-40） *** demography and biology were *** molecular markers associated with a phenotypic response of plant resistance were detected in segregating populations（Bc 2）.Results showed that although female survival time was similar on all hosts,the lowest averages of longevity,fecundity and oviposition rate were observed in the resistant control MEcu- 72,only being significantly similar to the parent *** the Bc 1 and Bc 2 populations were compared,it was found that *** fecundity was eight times lower on cMB9B-73 progeny than on cW67-130,expressing the highest levels of resistance to the *** genotypes of cMB9A and cMB9B family had the best segregation.A total of 486 microsatellite primers were evaluated using bulked segregant analysis（BSA）,11 showed polymorphism between the contrasting pools and only one showed significant differences between resistant and susceptible *** conclusion,fecundity was the parameter that impacted most on the intrinsic rate of *** population growth.

关键词： cassava wild parents interspecific hybrids whitefly resistance BSA

The assembly of the Milky Way and its satellite galaxies

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2012年第8期12卷 1021-1043页

作者： martin c. Smith Sakurako Okamoto Hai-Bo Yuan Xiao-Wei Liu Kavli Institute for Astronomy and Astrophysics Peking University Beijing 100871 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China LAMOST Fellow Department of Astronomy Peking University Beijing 100871 China

In recent years it has become clear that the Milky Way is an important test- ing ground for theories of galaxy formation. Much of this growth has been driven by large surveys, both photometric and spectroscopic, which are producing vast and rich catalogs of data. Through the analysis of these data sets we can gain new and detailed insights into the physical processes which shaped the Milky Way＇s evolution. This review will discuss a number of these developments, first focusing on the disk of the Milky Way, and then looking at its satellite population. The importance of surveys has not gone unnoticed by the chinese astronomy community and in the final section we discuss a number of chinese projects that are set to play a key role in the development of this field.

关键词： Galaxy: structure -- Galaxy: evolution -- Galaxy: kinematics and dy-namics -- Galaxy: disk -- galaxies: dwarf-- surveys