检索结果-南通市图书馆

Revealing the residual stress distribution in laser welded Eurofer97 steel by neutron diffraction and Bragg edge imaging

引用

journal of Materials Science & Technology 2022年第19期114卷 249-260页

作者： Bin Zhu Nathanael Leung Winfried Kockelmann Saurabh Kabra Andrew jLondon michael Gorley Mark jWhiting Yiqiang Wang Tan Sui School of Mechanical Engineering Sciences University of SurreyGuildfordSurrey GU27XHUnited Kingdom Science and Technology Facilities Council(STFC)Rutherford Appleton Laboratory ISIS FacilityHarwell OX110QXUnited Kingdom United Kingdom Atomic Energy Authority Culham Centre for Fusion EnergyCulham Science CentreAbingdonOxon OX143DBUnited Kingdom

Eurofer97 steel is a primary structural material for applications in fusion reactors. Laser welding is a promising technique to join Eurofer97 plasma-facing components and overcome remote handling and maintenance challenges. The interaction of the induced residual stress and the heterogeneous microstructure degrades the mechanical performance of such fusion components. The present study investigates the distribution of residual stress in as-welded and post-heat treated Eurofer97 joints. The mechanistic connections between microstructure, material properties, and residual stress are also studied. Neutron diffraction is used to study the through-thickness residual stress distribution in three directions,and neutron Bragg edge imaging(NBEI) is applied to study the residual strain in high spatial *** microstructures and micro-hardness are characterised by electron backscatter diffraction and nanoindentation, respectively. The M-shaped residual stress distribution through the thickness of the as-welded weldment is observed by neutron diffraction line scans over a region of 1.41 × 10 mm^(2). These profiles are cross-validated over a larger area(∼56 × 40 mm^(2)) with the higher spatial resolution by NBEI. The micro-hardness value in the fusion zone of the as-welded sample almost doubles from 2.75 ± 0.09 GPa to 5.06 ± 0.29 GPa due to a combination of residual stress and cooling-induced martensite. Conventional post weld heat treatment(PWHT) is shown to release ∼90% of the residual stress but not fully restore the microstructure. By comparing its hardness with that of stress-free samples, it is found that the microstructure is the primary contribution to the hardening. This study provides insight into the prediction of structural integrity for critical structural components of fusion reactors.

关键词： Laser-welded Eurofer97 steel Residual stress Neutron diffraction Neutron Bragg edge imaging Nanoindentation EBSD

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

First-principles calculations of hyperfine interaction,binding energy,and quadrupole coupling for shallow donors in silicon

引用

npj Computational Materials 2020年第1期6卷 186-194页

作者： michael W.Swift Hartwin Peelaers Sai Mu john j.L.Morton Chris G.Van de Walle Department of Physics University of CaliforniaSanta BarbaraCA 93106-9530USA US Naval Research Laboratory Center for Computational Materials ScienceWashingtonDC 20375USA Materials Department University of CaliforniaSanta BarbaraCA 93106-5050USA Department of Physics and Astronomy University of KansasLawrenceKansas 66045USA Department of Electronic and Electrical Engineering UCLLondonWC1E 7JEUK

Spin qubits based on shallow donors in silicon are a promising quantum information technology with enormous potential scalability due to the existence of robust silicon-processing ***,the most accurate theories of donor electronic structure lack predictive power because of their reliance on empirical fitting parameters,while predictive ab initio methods have so far been lacking in accuracy due to size of the donor wavefunction compared to typical simulation *** show that density functional theory with hybrid and traditional functionals working in tandem can bridge this *** first-principles approach allows remarkable accuracy in binding energies(67 meV for bismuth and 54 meV for arsenic)without the use of empirical *** also obtain reasonable hyperfine parameters(1263 MHz for Bi and 133 MHz for As)and superhyperfine *** demonstrate the importance of a predictive model by showing that hydrostatic strain has much larger effect on the hyperfine structure than predicted by effective mass theory,and by elucidating the underlying mechanisms through symmetry analysis of the shallow donor charge density.

关键词： density donor hyperfine

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

Transcription factors CncC and Maf connect the molecular network between pesticide resistance and resurgence of pest mites

引用

Insect Science 2022年第3期29卷 801-816页

作者： Guang-Mao Shen Shi-Yuan Ou Chuan-Zhen Li Kai-Yang Feng jin-Zhi Niu michael j.Adang Lin He Key Laboratory of Entomology and Pest Control Engineering College of Plant ProtectionSouthwest UniversityChongqingChina Academy of Agricultural Sciences Southwest UniversityChongqingChina State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University Southwest UniversityChongqingChina Department of Entomology University of GeorgiaAthensGeorgiaUSA

Pesticide resistance and resurgence are serious problems often occurring simultaneously in the *** our long-term study of a fenpropathrin-resistant strain of Tetranychus cinnabaribus,enhancement of detoxification and modified fecundity mechanisms were both *** we investigate the network across these two mechanisms and find a key node between resistance and *** show that the ecdysone pathway is involved in regulating the fecundity of *** concentration change of ecdysone is consistent with the fecundity curve;the concentration of ecdysone is higher in the fenpropathrin-resistant strain which has stronger *** enhancement of ecdysone is due to overexpression of two P450 genes(CYP314A1 and CYP315A1)in the ecdysone synthesis *** expression of these CYP genes resulted in lower concentration of ecdysone,reduced expression of vitellogenin,and reduced fecundity of *** expression of CYP315A1 is regulated by transcription factors Cap-n-collar isoform C(CncC)and Musculoaponeurotic fibrosarcoma protein(Maf),which are involved in regulating other P450 genes functioning in detoxification of fenpropathrin in ***.A similar regulation is established in citrus pest mite Panonychus citri showing that the CncC pathway regulates expression of PcCYP315Al,which affects mite *** factors are activated to upregulate detoxification genes facilitating pesticide resistance,while the“one to multiple”regulation mode of transcription factors simultaneously increases expression of metabolic enzyme genes in hormone pathways and alters the physiology of *** is an important response of arthropods to pesticides which leads to resistance and population resurgence.

关键词： resistance resurgence Tetranychus cinnabarinus transcription factor

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

Vaccine breakthrough and rebound infections modeling:Analysis for the United States and the ten *** regions

引用

Infectious Disease Modelling 2023年第3期8卷 717-741页

作者： Olusegun michael Otunuga Alexandra Yu Department of Mathematics Augusta University112015th StrGE 2018AugustaGA30912USA

A vaccine breakthrough infection and a rebound infection cases of COVID-19 are studied and analyzed for the ten *** of Health and Human Services(HHS)regions and the United States as a nation in this *** innovative multi-strain susceptible-vacci-nated-exposed-asymptomatic-symptomatic-recovered(SVEAIR)epidemic model is devel-oped for this purpose for a population assumed to be susceptible to n-different variants of the disease,and those who are vaccinated and recovered from a specific strain k(kn)of the disease are immune to present strain and its predecessors j=1,2,…,k,but can still be infected by newer emerging strains j=k+1,k+2,…,*** model is used to estimate epidemiological parameters,namely,the latent and infectious periods,the transmission rates,vaccination rates,recovery rates for each of the Delta B.1.617.2,Omicron B.1.1.529,and lineages BA.2,BA.2.12.1,BA.4,BA.5,BA.1.1,BA.4.6,and BA.5.2.6 for the United States and for each of the ten HHS *** transmission rate is estimated for both the asymptomatic and symptomatic *** effect of vaccines on each strain is *** that guarantees existence of an endemic with certain number of strains is derived and used to describe the endemic state of the population.

关键词： Multi-strain Delta Omicron Lineages Vaccine breakthrough Rebound infection

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

Sensorized tissue analogues enabled by a 3D-printed conductive organogel

引用

npj Flexible Electronics 2021年第1期5卷 51-58页

作者： michael R.Crump Sophia L.Bidinger Felippe j.Pavinatto Alex T.Gong Robert M.Sweet Devin MacKenzie Department of Materials Science&Engineering University of WashingtonSeattleWAUSA Center for Research in Education and Simulation Technologies University of WashingtonSeattleWAUSA Department of Surgery University of WashingtonSeattleWAUSA Department of Mechanical Engineering University of WashingtonSeattleWAUSA

State-of-the-art tissue analogues used in high-fidelity,hands-on medical simulation modules can deliver lifelike appearance and feel but lack the capability to provide quantified,real-time assessment of practitioner *** monolithic fabrication of hybrid printed/textile piezoresistive strain sensors in a realistic Y/V plasty suture training pad is demonstrated.A class of 3D-printable organogels comprised of inexpensive and nonhazardous feedstocks is used as the sensing medium,and conductive composite threads are used as the *** organogels are comprised of a glycol-based deep-eutectic solvent(DES)serving as the ionic conductor and 3-trimethoxysilylmethacrylate-capped fumed silica particles serving as the gelating *** measurements reveal the influence of fumed silica particle capping group on the mixture *** strain sensors demonstrate a maximum strain amplitude of 300%,negligible signal drift,a monotonic sensor response,a low degree of hysteresis,and excellent cyclic *** increased contact resistance of the conductive thread electrodes used in place of wire electrodes do not make a significant impact on sensor *** work showcases the potential of these organogels utilized in sensorized tissue analogues and freestanding strain sensors for widespread applications in medical simulation and education.

关键词： stability analogues conductive

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

缺铜、缺锌对小鼠几种细胞因子产生的影响

引用

中华微生物学和免疫学杂志 1995年第6期15卷 20-20页

作者：金虹,B.M.Hannigan,j.j.strain 导师广州中医药大学第二附院科研科英国Ulster大学生物医学院英国Ulster大学生物医学院 510120

近年来,微量元素Cu和Zn与机体免疫的关系日益受到重视。许多研究发现,Cu和Zn对维持机体正常免疫和炎症反应起着重要作用。鉴于单核细胞因子TNF-α、IL-1和IL-6是宿主免疫和炎症反应的重要介质,本工作观察了缺铜和缺锌小鼠体内单核细胞... 详细信息

近年来,微量元素Cu和Zn与机体免疫的关系日益受到重视。许多研究发现,Cu和Zn对维持机体正常免疫和炎症反应起着重要作用。鉴于单核细胞因子TNF-α、IL-1和IL-6是宿主免疫和炎症反应的重要介质,本工作观察了缺铜和缺锌小鼠体内单核细胞因子产生的变化。实验采用AIN-76TM缺铜纯饲料,喂饲3周龄刚断奶的BALB/c雄性小鼠6周,虽然小鼠没有

关键词：小鼠小家鼠细胞因子缺锌

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Isothermal study of effusion cooling flows using a large eddy simulation approach

引用

航空动力学报 2009年第4期24卷 729-739页

作者： W.P.Bennett j.j.Mc Guirk Aeronautical and Automotive Engineering Department Loughborough University

An isothermal numerical study of effusion cooling flow is conducted using a large eddy simulation(LES) *** main types of cooling are considered,namely tangential film cooling and oblique patch effusion *** represent tangential film cooling,a simplified model of a plane turbulent wall jet along a flat plate in quiescent surrounding fluid is *** contrast to a classic turbulent boundary layer flow,the plane turbulent wall jet possesses an outer free shear flow region,an inner near wall region and an interaction region,characterised by substantial levels of turbulent shear stress *** shear stress characteristics hold significant implications for RANS modelling,implications that also apply to more complex tangential film cooling flows with non-zero free stream *** LES technique used in the current study provides a satisfactory overall prediction of the plane turbulent wall jet flow,including the initial transition region,and the characteristic separation of the zero turbulent shear stress and zero shear strain *** effusion patch cooling is modelled using a staggered array of 12 rows of effusion holes,drilled at 30° to the flat plate *** effusion holes connect two channels separated by the flat ***,these comprise of a channel representing the combustion chamber flow and a cooling air supply channel.A difference in pressure between the two channels forces air from the cooling supply side,through the effusion holes,and into the combustion chamber *** from successive effusion rows coalesces to form an aerodynamic film between the combustion chamber main flow and the flat *** practical applications,this film is used to separate the hot combustion gases from the combustion chamber *** numerical model is shown to be capable of accurately predicting the injection,penetration,downstream decay,and coalescence of the effusion *** addition,the numerical model captures entrainmen

关键词： effusion cooling large eddy simulation isothermal analysis film cooling turbulent wall jet

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

Studying turbulence structure near the wall in hydrodynamic flows:An approach based on the Schur decomposition of the velocity gradient tensor

引用

journal of Hydrodynamics 2022年第5期34卷 806-825页

作者： Christopher j.Keylock School of Architecture Building and Civil EngineeringLoughborough UniversityLeicestershireUK

The Schur decomposition of the velocity gradient tensor(VGT)is an alternative to the classical Cauchy-Stokes decomposition into rotation rate and strain rate ***,there have been several strands of work that have employed this decomposition to examine the physics of turbulence dynamics,including approaches that combine the Schur and Cauchy-Stokes *** are briefly reviewed before the latter approach is set *** partitions the rotation rate and strain rate tensors into normal/local and non-normal/non-local *** then study the relation between the VGT dynamics and ejection-sweep events in a channel flow *** show that the sweeps in particular exhibit novel behaviour compared with either the other quadrants,or the flow in general,with a much-reduced contribution to the dynamics from the non-normal terms above the viscous *** particular,the reduction in the production term that is the interaction between the non-normality and the normal straining reduces in the log-layer as a consequence of an absence of alignment between the non-normal vorticity and the strain rate *** have been early forays into using the Schur transform approach for subgrid-scale modelling in large-eddy simulation(LES)and this would appear to be an exciting way forward.

关键词： Turbulence channel flow velocity gradient tensor Schur decomposition

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

Exploring effects of property variation on fragmentation of metal rings using a simple model

引用

Defence Technology（防务技术） 2023年第5期23卷 1-7页

作者： j.D.Robson Department of Materials The University of ManchesterManchesterM139PLUK

A simple finite element implementation of the Mott model for fragmentation of a thin walled ring has been implemented and used to explore the effect of local variations in fracture strain around the *** model has successfully reproduced the fragment size distributions previously reported,which follow a characteristic“Mott distribution”form,providing sufficient(1000)simulations are *** has been shown that this form is retained even when there are large differences in the random distribution of fracture strains or a different choice of function used to describe the fracture strain *** these cases,the strain rate has a much stronger effect than fracture strain distribution the on the average fragment size and fragment ***,for cases where there are a small number of local defects that strongly reduce the fracture strain at certain locations around the ring,the predicted fragment size distribution develops a bimodal *** is also the case for large but gradual variations in fracture strain with position around the *** results have implications for cases where a small number of large pre-existing defects exist,or processing has led to macrozones in the *** utility of a simple fast running model to study these cases is discussed.

关键词： Fragmentation Mott model Property variation

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

Microstructure and tensile properties of magnesium nanocomposites fabricated using magnesium chips and carbon black

引用

journal of Magnesium and Alloys 2020年第3期8卷 860-872页

作者： T.j.Lee W.j.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

In this study,carbon black(0,0.01,0.03 and 0.08 wt%)and AZ31(Mg-3Al-lZn)magnesium chips were used to fabricate carbon black-reinforced magnesium matrix composites with extrusion or a combination of extrusion and high-ratio differential speed *** hot pressing at 693 K and extrusion at 623 K with an extrusion ratio of 22,the magnesium chips coated with carbon black were soundly bonded into a bulk composite *** grain sizes of the extruded materials were similar with a size of 48.2-51.5|im despite the difference in the amount of carbon *** yield strength and ultimate tensile strength increased from 177 to 191 MPa and from 240 to 265 MPa,respectively,as a result of the addition of 0.01%carbon black;however,a further increase in the strength was marginal with additional carbon *** same trend was observed in the strain hardening *** tensile elongation increased by to the addition of 0.01%carbon black(from 15.8%to 17.4%)due to the increased work hardening effect,but decreased with additional carbon black due to its agglomeration and poor dispersion at higher *** high-ratio differential speed rolling(HRDSR)on the extruded materials and subsequent annealing,the AZ31 and AZ31 composites had a similar fine grain size of 16.3-17.9 *** annealed HRDSR composites showed the best mechanical properties at a higher content of carbon black(0.03%)compared to that(0.01%)for the extruded *** resulted from the enhanced dispersion effect of the carbon black due to the high shear flow induced during the HRDSR *** extruded composites exhibited the three distinct hardening stages(stage II,stage III and stage IV),while the annealed HRDSR composites mainly displayed the stage III *** addition of carbon black increased the strain hardening rate at all the strain hardening stages in both of the extruded and annealed HRDSR *** the initial hardening stage,the strain hardening rates of the extruded comp

关键词： Recycling Magnesium alloys chips Carbon black Nanocomposites Extrusion Differential speed rolling

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：