检索结果-南通市图书馆

Chinese Physics B 2024年第1期33卷 32-43页

作者：李平刘邦陈帅张蔚曦郭志新 state key {2. for mechanical behavior of materials Center for Spintronics and Quantum SystemSchool of Materials Science and EngineeringXi'an Jiaotong UniversityXi'an 710049China state key {2. for Surface Physics and Department of Physics Fudan UniversityShanghai 200433China Jinan Aviation Repair Factory Jinan 250000China Department of Physics and Electronic engineering Tongren UniversityTongren 554300China

The electron's charge and spin degrees of freedom are at the core of modern electronic devices. With the in-depth investigation of two-dimensional materials, another degree of freedom, valley, has also attracted tremendous research interest. The intrinsic spontaneous valley polarization in two-dimensional magnetic systems, ferrovalley material, provides convenience for detecting and modulating the valley. In this review, we first introduce the development of ***, the valley polarization forms by the p-, d-, and f-orbit that are discussed. Following, we discuss the investigation progress of modulating the valley polarization of two-dimensional ferrovalley materials by multiple physical fields, such as electric, stacking mode, strain, and interface. Finally, we look forward to the future developments of valleytronics.

关键词： ferrovalley valley polarization two-dimensional materials multi-field tunable

在线全文

学校读者我要写书评

暂无评论

高强金属丝材的力学行为与变形机理

科学通报 2024年第21期69卷 3154-3176页

作者：陈金玺徐彬戴兰宏陈艳中国科学院力学研究所非线性力学国家重点实验室北京100190 中国科学院大学工程科学学院北京101408

金属丝材作为一类独特的结构及功能材料,具有悠久的发展历史,并在诸多领域发挥着不可替代的作用.目前,人们已经发展了多种成熟的丝材加工工艺,并制备出多种高强韧金属丝材.其中,传统珠光体钢丝保持着金属丝材最高抗拉强度的世界纪录,而... 详细信息

金属丝材作为一类独特的结构及功能材料,具有悠久的发展历史,并在诸多领域发挥着不可替代的作用.目前,人们已经发展了多种成熟的丝材加工工艺,并制备出多种高强韧金属丝材.其中,传统珠光体钢丝保持着金属丝材最高抗拉强度的世界纪录,而新型高熵合金丝材成功克服了传统丝材强度与塑性之间的矛盾关系和低温脆性的问题,显示出在复杂服役环境下的巨大应用潜力.由于金属丝材各异的微观结构和物理化学特性,其表现出各自独特的力学行为和复杂迥异的强塑性变形机理.多晶合金丝材的高强度主要源于界面强化和位错强化等多种强化机制的共同作用,其塑性变形涉及位错运动和变形孪生等多种复杂的塑性变形机理;非晶合金丝材的高强度源于其本征的原子无序结构,其塑性变形则主要与流动缺陷的激活与聚集有关.为了进一步实现金属丝材强韧化,研究者提出了微观组织细化和不均匀结构设计等有效途径.随着金属丝直径的减小,变形尺寸效应显现,考虑尺寸效应的应变梯度塑性理论相继发展并有效应用于金属丝材力学行为描述.本文对金属丝材的发展历史、制备工艺和典型高强金属丝材的力学行为、强塑性变形机理以及本构模型进行了回顾与综述,并对未来研究值得关注的方向提出了几点展望.

关键词：金属丝材制备工艺力学行为塑性变形机理本构模型

Crystal plasticity behavior of single-crystal pure magnesium under plane-strain compression

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2017年第7期36卷 541-549页

作者： Bai-Li xi Gang Fang Department of mechanical engineering Tsinghua University Beijing 100084China state key {2. of Tribology Beijing 100084China

A phenomenological crystal plasticity constitu- tive model for magnesium single crystal was presented. Four deformation mechanisms （including basal （a）, pris- matic （a）, pyramidal （c ＋ a） slip and tension twin） and their interactions were considered. Twin-induced lattice reorientation was also incorporated in the model. The proposed model was then applied to the simulation of plane-strain compression deformation for different orien- tations. Related material parameters were calibrated at first according to the classical channel-die tests. The predicted macro-and microscopic responses, along with the experi- mental results, show strong orientation-dependent proper- ties. It is also found in the simulation that basal slip in the twinned region is active even before the saturation of twin activity in a twin-favored case. Furthermore, the effect of an initial deviation angle on the mechanical responses was evaluated, which is proved to be also orientation-depen- dent. Basal slip is found to be easily activated due to a slight deviation, while a slight deviation in the twin-fa- vored case could result in a significant difference in the mechanical behavior after the reorientation. The effort on the study of magnesium single crystal in the present work contributes to further polycrystalline analysis.

关键词： Magnesium Crystal plasticity Slip and twin Orientation deviation

IMPULSIVE LOADING OF A FULLY CLAMPED CIRCULAR METALLIC FOAM CORE SANDWICH PLATE

在线全文

学校读者我要写书评

暂无评论

IMPULSIVE LOADING OF A FULLY CLAMPED CIRCULAR METALLIC FOAM ...

Numerical Simulation of Fluid Flow Caused by Buoyancy Forces During Vacuum Arc Remelting Process

The 7th International Conference on Shock and Impact Loads on Structures

作者： Qing Hua Qin~* xi’an jiaotong University {2. T.J.Wang xi’an jiaotong University {2.

＜正＞The dynamic response of large deflection of a fully clamped circular metallic foam core sandwich plate under axially symmetric impulsive loading is studied in this paper A new yield criterion is proposed,which is valid for the metallic sandwich crosssection with different core strength and can be reduced to the classical yield criteria for the solid monolithic and weak core sandwich cross-section,***, the approximately inscribed and circumscribed yield criteria are developed and new‘bound’predictions of the problem are obtained,which are smaller than that based on the classical yield ***,mode approximation method is used to derive the exact solutions for the *** of the present solutions with finite element numerical results are presented and good agreements are found.

关键词： blast-resistant structure metallic sandwich plate yield criterion dynamic response large deflection.

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Shanghai jiaotong university(science) 2011年第3期16卷 272-276页

作者：赵小花李金山杨治军寇宏超胡锐周廉 state key {2. of Solidification Processing Northwestern Polytechnical University

The metallurgical structure and composition of ingots which depend critically on the fluid motion within the molten pool during the vacuum arc remelting(VAR)process have important effect on the subsequent mechanical processes like forging,rolling and *** order to determine the fluid motion of molten pool,a 2. finite element model is established using ANSYS10.0 software,combined with the turbulent fluid flow and heat *** fluid motion caused by thermo buoyancy forces is investigated at different VAR processes in the present *** results indicate that the fluid flows symmetrically along the axis of the molten pool and clockwisely along the circle at the right pool’s *** is also shown that the maximum velocity increases with increasing melting rate and a direct proportional relationship exists.

关键词： vacuum arc remelting(VAR) fluid flow buoyancy force numerical simulation

5-HT2. receptor mediates the ventrolateral orbital cortex-evoked antiallodynia in a neuropathic pain model of rats:A possible presynaptic facilitatory effect

在线全文

学校读者我要写书评

暂无评论

5-HT2A receptor mediates the ventrolateral orbital cortex-ev...

基于Pareto控制的多目标PSO算法在铣削参数优化中的应用

中国生理学会第2.届全国会员代表大会暨生理学学术大会

作者： Feng-Yi XU,Fu-Quan HUO~*,Chao-Ling QU,Jing-Shi TANG Department of Physiology and Pathophysiology,key laboratory of Environment and Genes Related to Diseases,Ministry of Education,{2.’an jiaotong University school of Medicine,{2.’an 710061,china

Previous studies have indicated that the ventrolateral orbital cortex(VLO),as a high center,is involved in an endogenous analgesic system consisting of a spinal cord-thalamic nucleus submedius-VLO-periaqueductal gray(PAG)-spinal cord *** study has showed that 5-HT receptor is involved in the VLO mediated descending antinociception in the tail flick ***,it is unknown,under neuropathic pain state,whether the VLO 5-HT receptor is also *** the 5-HT receptor is an excitatory G-protein coupled receptor and is distributed not only in the postsynaptic neurons,but also in presynaptic neurons or ***,we suppose that activation of 5-HT receptor induced anti-neuropathic pain in VLO may be produced,except for by postsynaptic direct activation of the VLO neurons projecting to PAG,also probably through a presynaptic facilitatory effect on the excitatory glutamate synapse transmission,leading to activation of the VLO-PAG brainstem descending inhibitory system and depression of the nociceptive inputs at the spinal *** provide support for this hypothesis,the current study was designed to examine whether 5-HT receptor activation-induced anti-allodynia could be blocked by glutamate receptor antagonist and enhanced by its *** withdrawal threshold(PWT) as an index of nociceptive response was measured in response to mechanical stimulation(von Frey filaments) in the spared nerve injury(SNI) *** effect of microinjection of drugs into the VLO on the PWT was *** results showed that microinjection of DOI(2.4,8,16 nmol/0.5μL),a selective 5-HT receptor agonist,into VLO attenuated SNI-induced mechanical allodynia in a dose-dependent *** effect was completely blocked by the selective 5-HT receptor antagonist ketanserin tartrate salt(10 nmol/0.5μL) or significantly attenuated by premicroinjection of a non-selective glutamate receptor antagonist kynurenic acid(KA,2.nmol/0.5μL) into VLO.A small dose(2. nmol/0.5μL) of gl

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

重庆理工大学学报（自然科学） 2024年第1期38卷 237-247页

作者：王奇陈曦刘海妹赵彻徐波常州工学院航空与机械工程学院江苏常州213032 上海交通大学机械系统与振动国家重点实验室上海200240

工艺参数是影响零件加工质量和效率的关键因素,工艺参数的优化和调节是改善加工工艺的最有效方法。针对铣削加工参数优化问题,提出了一种基于应用实例的多目标切削参数优化方法。首先,以材料去除率、切削力和刀具寿命为目标函数,建立了... 详细信息

工艺参数是影响零件加工质量和效率的关键因素,工艺参数的优化和调节是改善加工工艺的最有效方法。针对铣削加工参数优化问题,提出了一种基于应用实例的多目标切削参数优化方法。首先,以材料去除率、切削力和刀具寿命为目标函数,建立了统一的切削工艺参数多目标优化数学模型。随后,使用切削数据对目标函数进行组合,建立了该问题的数学模型,研究了适用的求解方法以获得最优解,并通过实验验证了参数优化的有效性。该方法可为加工参数的选择提供指导和依据。

关键词：铣削参数优化刀具寿命 Pareto控制的粒子群优化

Energy Absorption Characteristics of a Novel Asymmetric and Rotatable Re-entrant Honeycomb Structure

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2021年第4期34卷 550-560页

作者： Huifeng xi Jiachu Xu Shende Cen Shiqing Huang MOE key laboratory of Disaster Forecast and Control in {2. and school of Mechanics and Construction {2. Jinan UniversityGuangzhou510632China

Based on the symmetric re-entrant honeycomb(S-RH)structure with negative Poisson’s ratios,a novel asymmetric and rotatable re-entrant honeycomb(AR-RH)structure was *** the S-RH structure and AR-RH structure were produced by the 3D printing *** experimental test and finite element simulation,the deformation mechanism and energy absorption characteristics of the AR-RH structure and the S-RH structure with negative Poisson’s ratios at different impact velocities were *** experimental test and finite element simulation results show that the novel AR-RH structure with negative Poisson’s ratios has stronger energy absorption capacity than the S-RH structure,and it has been verified that the rotatability of AR-RH can indeed absorb ***,the degree of asymmetry of the AR-RH structure was discussed.

关键词： Asymmetric and rotatable re-entrant honeycomb structure Dynamic compression Energy absorption characteristics Metal 3D printing technology

A combined experimental and analytical method to determine the EHL friction force distribution between rollers and outer raceway in a cylindrical roller bearing

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

Friction 2023年第8期11卷 1455-1469页

作者： Yu HOU xi WANG Di YANG Zeliang xiAO school of mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Hunan Provincial key laboratory of Intelligent Manufacturing Technology for High-performance {2. Equipment Changsha University of Science and TechnologyChangsha 410114China

Friction force is a crucial factor causing power loss and fatigue spalling of rolling element bearings.A combined experimental and analytical method is proposed to quantitatively determine the elastohydrodynamic lubrication(EHL)friction force distribution between rollers and outer raceway in a cylindrical roller bearing(CRB).An experimental system with the instrumented bearing and housing was developed for measuring radial load distribution and friction torque of bearings.A simplified model of friction force expressed by dimensionless speed,load,and material parameters was *** inequality constrained optimization problem was established and solved by using an experimental data-driven learning algorithm for determining the uncertain parameters in the *** effect of speed,load,and lubricant property on friction force and friction coefficient was discussed.

关键词： cylindrical roller bearing(CRB) elastohydrodynamic lubrication(EHL) friction force distribution friction torque combined method