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具有K个储备部件和N个故障状态可修复系统主算子性质
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作者 赵志欣 乔兴 任寒景 《数学的实践与认识》 北大核心 2019年第8期181-187,共7页
研究了具有N个故障状态和K个储备部件的可修复系统.将系统转化为Bancah空间中的Cauchy问题,分析了系统主算子的谱特征.运用正算子及共尾等理论,证明了系统主算子的增长界和谱上界相等.
关键词 共尾 谱上界 可修复系统
可修复人机系统的指数稳定性
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作者 梁彦珍 原文志 《数学的实践与认识》 北大核心 2017年第2期200-214,共15页
研究了两相同部件温储备可修的人机系统,运用C0半群的相关理论,对系统主算子的谱界进行估值.估算系统的算子产生的半群的增长界,然后运用了共尾的概念及相关的理论,得到了系统算子A+B的谱界与系统算子产生的半群的增长界相同.进而运用... 研究了两相同部件温储备可修的人机系统,运用C0半群的相关理论,对系统主算子的谱界进行估值.估算系统的算子产生的半群的增长界,然后运用了共尾的概念及相关的理论,得到了系统算子A+B的谱界与系统算子产生的半群的增长界相同.进而运用相关代数知识证得,0为系统算子的简单本征值,并分析了系统算子的谱分布,得到系统的指数稳定性.并研究了系统算子预解式的特性.对任意给定的δ〉0,γ=a+bi, 展开更多
关键词 预解正算子 谱分布 谱界 共尾 增长界 指数稳定性
The Matrix Stiffness and Physical Confinement of Hydrogel Microchannel Jointly Induce the Mesenchymal-Amoeboid Transition for Cancer Cell Migration
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作者 Meng Wang Bo Cheng +4 位作者 Yaowei Yang Han Liu Guoyou Huang Fei Li Feng Xu 《医用生物力学》 CAS CSCD 北大核心 2019年第A01期137-138,共2页
The migration mode transition of cancer cell enhances its invasive capability and the drug resistance,where physical confinement of cell microenvironment has been revealed to induce the mesenchymal-amoeboid transition... The migration mode transition of cancer cell enhances its invasive capability and the drug resistance,where physical confinement of cell microenvironment has been revealed to induce the mesenchymal-amoeboid transition(MAT).However,most existing studies are performed in PDMS microchannels,of which the stiffness is much higher than that of most mammalian tissues.Therefore,the amoeboid migration transition observed in these studies is actually induced by the synergistic effect of matrix stiffness and confinement.Since the stiffness of cell microenvironment has been reported to influence the cell migration in 2D substrate,the decoupling of stiffness and confinement effects is thus in need for elucidating the underlying mechanism of MAT.However,it is technically challenging to construct microchannels with physiologically relevant stiffness and channel size,where existing microchannel platforms with physiological relevance stiffness are all with>10μm channel width.Such size is too wide to mimic the physical confinement that migrating cancer cells confront in vivo,and also larger than the width of PDMS channel,in which the MAT of cancer cell was observed.Therefore,an in vitro cell migration platform,which could mimic both stiffness and confinement of the native physical microenvironment during cancer metastasis,could profoundly contribute to researches on cancer cell migration and cellular mechanotransduction.In this paper,we overcome the limitations of engineering soft materials in microscale by combining the collagen-alginate hydrogel with photolithography.This enables us to improve the accuracy of molded microchannel,and thus successfully construct a 3D microchannel platform,which matches the stiffness and width ranges of native environmental confinement that migrating cancer cells confront in vivo.The stiffness(0.3~20 kPa),confinement(channel width:3.5~14μm)and the adhesion ligand density of the microchannel can be tuned independently.Interestingly,using this platform,we observed that the migration speed of cancer 展开更多
关键词 The MATRIX STIFFNESS PHYSICAL CONFINEMENT HYDROGEL MICROCHANNEL Jointly Cancer Cell Migration MATRIX
Development of Zeff diagnostic system on the Globus-M (M2) tokamak and the first experimental results
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作者 E A TUKHMENEVA S Yu TOLSTYAKOV +8 位作者 G S KURSKIEV V K GUSEV V B MINAEV Yu V PETROV N V SAKHAROV A Yu TELNOVA N N BAKHAREV P B SHEGOLEV E O KISELEV 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第10期33-39,共7页
Studying the behavior of effective ion charge Zeff, which indicates the degree of pollution of plasma and can provide valuable information about many processes taking place in plasma, mechanisms of the releasing impur... Studying the behavior of effective ion charge Zeff, which indicates the degree of pollution of plasma and can provide valuable information about many processes taking place in plasma, mechanisms of the releasing impurities, transport, etc is of great interest. This paper describes the development of the Zeff diagnostic system for the Globus-M2 tokamak. The effective ion charge is determined on the basis of measurements of the bremsstrahlung intensity and Thomson scattering data-Te and ne profiles. The results of the first Zeff measurements obtained for several discharges on the Globus-M tokamak are presented in this paper. The results have been validated by simulation using the ASTRA transport code for the same discharges, and it has demonstrated a good agreement with the experimental results. 展开更多
关键词 TOKAMAK effective ion CHARGE magnetic CONFINEMENT
Mechanical behavior of micaceous clays 预览
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作者 Jiahe Zhang Amin Soltani +1 位作者 An Deng Mark B.Jaksa 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第5期1044-1054,共11页
This study aims to investigate the effect of mica content on the mechanical properties of clays.Commercially available ground mica was blended with a locally available clayey soil,at varying mica contents by mass of 5... This study aims to investigate the effect of mica content on the mechanical properties of clays.Commercially available ground mica was blended with a locally available clayey soil,at varying mica contents by mass of 5%,10%,15%,20%,25%and 30%,to artificially prepare various micaceous clay blends.The preliminary testing phase included consistency limits and standard Proctor compaction tests.The primary testing program consisted of unconfined compression(UC),direct shear(DS)and scanning electron microscopy(SEM)tests.The test results showed that the liquid and plastic limits exhibited a linear,monotonically increasing trend with increase in mica content.The rate of increase in the plastic limit,however,was found to be greater than that of the liquid limit,thereby leading to a gradual transition towards a non-plastic,cohesionless character.The soft,spongy fabric and high water demand of the mica mineral led to higher optimum water contents and lower maximum dry unit weights with increasing mica content.Under low confinement conditions,i.e.the UC test and the DS test at low normal stresses,the shear strength was adversely affected by mica.However,the closer packing of the clay and mica components in the matrix under high confinement conditions offsets the adverse effects of mica by inducing frictional resistance at the shearing interface,thus leading to improved strength resistance. 展开更多
关键词 Micaceous CLAY MICA content CONSISTENCY limits COMPACTION SHEAR strength CONFINEMENT Frictional resistance
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碳纤维增强复材环向围束加固柱受低速冲击剩余承载力研究
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作者 王步 毕铁川 +2 位作者 孙振月 朱慧荣 张诺亚 《工业建筑》 CSCD 北大核心 2019年第6期192-198,共7页
外贴纤维增强复合材料(CFRP)环向围束钢筋混凝土柱受低速撞击时,因各向异性材性而易发生冲击损伤。基于显式有限元分析获得的不同低速冲击工况下CFRP环向围束加固柱的损伤结果,通过显式-隐式连续求解,建立了具有低速冲击损伤特征的CFRP... 外贴纤维增强复合材料(CFRP)环向围束钢筋混凝土柱受低速撞击时,因各向异性材性而易发生冲击损伤。基于显式有限元分析获得的不同低速冲击工况下CFRP环向围束加固柱的损伤结果,通过显式-隐式连续求解,建立了具有低速冲击损伤特征的CFRP环向围束加固柱的非线性隐式有限元分析模型,对包括冲击初始动能、CFRP厚度和撞击物形状在内的多种因素对加固柱的剩余受压承载力的影响效果进行了系统性的量化分析。 展开更多
关键词 碳纤维增强复合材料 低速冲击 约束 有限元方法
重复荷载作用下T形截面柱箍筋约束混凝土加卸载准则
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作者 王晓伟 李政儒 +1 位作者 卿龙邦 慕儒 《建筑结构学报》 EI CAS CSCD 北大核心 2019年第12期169-177,共9页
为研究T形截面柱箍筋约束混凝土在重复荷载作用下的加卸载模型,在已有5根箍筋约束混凝土T形截面柱轴心重复受压性能试验研究基础上,采用ANSYS有限元软件对其受力过程进行分析,研究了T形截面柱箍筋对核心混凝土的有效约束作用。综合有限... 为研究T形截面柱箍筋约束混凝土在重复荷载作用下的加卸载模型,在已有5根箍筋约束混凝土T形截面柱轴心重复受压性能试验研究基础上,采用ANSYS有限元软件对其受力过程进行分析,研究了T形截面柱箍筋对核心混凝土的有效约束作用。综合有限元分析结果及试验结果,建立了T形截面柱约束混凝土的抗压强度和峰值应变计算式,计算值与试验值吻合良好。通过分析重复荷载作用下箍筋约束混凝土的应力-应变包络线、共同点轨迹线的特征,发现共同点轨迹线与包络线形状相似,给出了应力-应变包络线方程,计算结果与试验结果吻合良好。据此建立了重复荷载作用下T形截面柱箍筋约束混凝土的卸载曲线、再加载曲线方程,计算曲线与试验曲线吻合较好,说明建议的加卸载准则能较好地反映轴压重复荷载作用下箍筋约束混凝土的应力-应变曲线的变化规律。 展开更多
关键词 T形截面柱 箍筋 约束 重复荷载 加卸载准则
限位环境对妊娠母猪母性的影响 预览 被引量:1
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作者 关立伟 于浪潮 +1 位作者 赵晓宇 尹国安 《家畜生态学报》 北大核心 2019年第5期87-90,共4页
限位环境在带来生产便利的同时也限制了母猪的母性表达。从中枢控制、基因表达、激素调节等角度阐明母性行为的发生机制,分析限位环境应激对母猪行为、生理、心理等方面的影响导致的母性减弱,并总结限位母猪常见疾病对母性的影响;通过... 限位环境在带来生产便利的同时也限制了母猪的母性表达。从中枢控制、基因表达、激素调节等角度阐明母性行为的发生机制,分析限位环境应激对母猪行为、生理、心理等方面的影响导致的母性减弱,并总结限位母猪常见疾病对母性的影响;通过对限位环境中母性表达影响因素的分析,探究其在妊娠母猪中的作用机制,将有助于改进母猪的育种和管理。 展开更多
关键词 妊娠母猪 限位 母性行为 基因 激素
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Study on Lateral compression deformation and constitutive relation of filling body 预览
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作者 Lifei Li 《探索-地质与矿业研究》 2019年第1期15-17,共3页
In order to study the mechanical behavior of the filling body under compression under deep high stress,Select concentration70%,Gray sand ratio1.:10,Curing age respectively14d, 28D, 56dConfined consolidation experiment... In order to study the mechanical behavior of the filling body under compression under deep high stress,Select concentration70%,Gray sand ratio1.:10,Curing age respectively14d, 28D, 56dConfined consolidation experiments under different stress loading levels of classified tailings cemented filling body,The results show that:The axial compression gradually increases with the increase of stress loading level.,Logarithmic function relationship with axial stress;The relationship between axial strain and stress is quadratic function. 展开更多
关键词 FILLING body CONFINED CONSOLIDATION CONSTITUTIVE RELATION DEFORMATION
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约束固化土承载特性和机理初探
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作者 刘金龙 李世洋 +3 位作者 刘兴华 李建平 高政国 黄新 《岩土工程学报》 EI CAS CSCD 北大核心 2019年第A01期229-232,共4页
将液性指数为0.26~1.19的土样与含不同比例膨胀组分的固化剂拌合制备固化土,并填充于约束刚度不同、外径11 cm、高20 cm的PVC筒中养护成型。测定固化土养护期间约束体的环向应变。分别对去除约束体的无约束固化土和带约束体的约束固化... 将液性指数为0.26~1.19的土样与含不同比例膨胀组分的固化剂拌合制备固化土,并填充于约束刚度不同、外径11 cm、高20 cm的PVC筒中养护成型。测定固化土养护期间约束体的环向应变。分别对去除约束体的无约束固化土和带约束体的约束固化土进行轴压试验,测定试件的环向应变、竖向位移与荷载的关系。得出以下结论:①在固化剂掺量相等的条件下,约束固化土的极限承载力约为常规无约束固化土的5倍;根据约束固化土极限承载力和核芯固化土面积计算的视强度可达30MPa以上。②将约束体和膨胀性固化剂结合,可提高膨胀组分的比例以提高AFt的生成量、提高孔隙填充率,从而提高核芯固化土强度;AFt的膨胀给核芯固化土施加预压应力,进一步提高约束体对核芯固化土的约束能力;这些效应的综合作用使约束固化土获得更高的承载力。③约束固化土荷载–位移曲线呈现斜率较大的线性阶段,近似线性、斜率较小的阶段2,斜率几乎为零的阶段3。④约束固化土在线性阶段,主要由结构保持整体性的核芯固化土承受荷载;阶段2,固化土结构逐步解体,约束体承受的荷载逐步增加;约束固化土破坏均因约束体失效。 展开更多
关键词 固化土 约束 膨胀 预应力 承载特性
A novel spoof surface plasmon polariton structure to reach ultra-strong field confinements 预览
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作者 Pei Hang He Hao Chi Zhang +5 位作者 Xinxin Gao Ling Yun Niu Wen Xuan Tang Jiayuan Lu Le Peng Zhang Tie Jun Cui 《光电进展(英文)》 2019年第6期9-15,共7页
Ultrathin corrugated metallic structures have been proved to support spoof surface plasmon polariton (SPP) modes on two-dimension (2D) planar microwave circuits.However,to provide stronger field confinement,larger wid... Ultrathin corrugated metallic structures have been proved to support spoof surface plasmon polariton (SPP) modes on two-dimension (2D) planar microwave circuits.However,to provide stronger field confinement,larger width of strip is required to load deeper grooves,which is cumbersome in modern large-scale integrated circuits and chips.In this work,a new spoof SPP transmission line (TL) with zigzag grooves is proposed.This new structure can achieve stronger field confinement compared to conventional one with the same strip width.In other words,the proposed spoof SPP TL behaves equivalently to a conventional one with much larger size.Dispersion analysis theoretically indicates the negative correlation between the ability of field confinement and cutoff frequencies of spoof SPP TLs.Numerical simulations indicate that the cutoff frequency of the proposed TL is lower than the conventional one and can be easily modified with the fixed size.Furthermore,two samples of the new and conventional spoof SPP TLs are fabricated for experimental demonstration.Measured S-parameters and field distributions verify the ultra-strong ability of field confinement of the proposed spoof SPP TL.Hence,this novel spoof SPP structure with ultra-strong field confinement may find wide applications in microwave and terahertz engineering. 展开更多
关键词 ultrathin corrugated metallic STRUCTURE surface PLASMON POLARITONS field CONFINEMENT ZIGZAG GROOVES
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Interface Electric Field Confinement Effect of High-Sensitivity Lateral Ge/Si Avalanche Photodiodes
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作者 Wenzhou Wu Zhi Liu +2 位作者 Jun Zheng Yuhua Zuo Buwen Cheng 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2019年第1期1-8,共8页
A novel lateral Ge/Si avalanche photodiode without a charge region is investigated herein using device physical simulation.High field is provided by the band-gap barrier and build-in field at the Ge/Si interface in th... A novel lateral Ge/Si avalanche photodiode without a charge region is investigated herein using device physical simulation.High field is provided by the band-gap barrier and build-in field at the Ge/Si interface in the vertical direction.Modulating the Si mesa thickness (0-0.4μm)and impurity concentration of the intrinsic Si substrate (1×10^16-4×10^16cm-3)strengthens the electric field confinement in the substrate region and provides a high avalanche multiplication in the Si region.When the Si mesa thickness is 0.3μm,and the impurity concentration of the Si substrate is 2× 10^16cm-3,the Lateral Avalanche PhotoDiode (LAPD)exhibits a peak gain of 246 under 1.55μm incident light power of -22.2dBm,which increases with decreasing light intensity. 展开更多
关键词 AVALANCHE photodiodes LATERAL structure electric field CONFINEMENT high gain
自驱动的Janus微球在具有不同障碍物的表面上的运动行为研究 预览
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作者 张红 宗奕吾 +1 位作者 杨明成 赵坤 《物理学报》 SCIE EI CAS CSCD 北大核心 2019年第13期233-239,共7页
自驱动粒子在靠近边界尤其是平面上障碍物的边界时,会展现出奇特的运动行为.本文通过实验研究了固定于平面上的微米级障碍物的几何效应(包括大小和形状)对双氧水驱动的Janus微球运动行为的影响.实验结果表明,当障碍物尺寸超过临界值后,... 自驱动粒子在靠近边界尤其是平面上障碍物的边界时,会展现出奇特的运动行为.本文通过实验研究了固定于平面上的微米级障碍物的几何效应(包括大小和形状)对双氧水驱动的Janus微球运动行为的影响.实验结果表明,当障碍物尺寸超过临界值后,自驱动的Janus微球会被其“捕获”并沿着其边界定向运动.自驱动粒子在障碍物边界的停留时间及运动速率随着双氧水浓度的增加而增大,且其在圆柱形障碍物边界和球形障碍物边界的停留时间及运动速率均随着障碍物直径的增加而增大.但在相同的双氧水浓度和障碍物直径条件下,自驱动粒子在圆柱边界上的停留时间比其在球形障碍物边界上长;在圆柱边界上的运动速率比在球形障碍物边界上小,揭示了自驱动粒子在障碍物边界上的运动行为与障碍物的几何特性密切相关.本研究有助于进一步理解自驱动粒子在不同大小及形状的障碍物中的运动特征,掌握并利用这些特征在诸如设计特殊几何形状来引导自驱动粒子的运动等领域有很好的应用价值. 展开更多
关键词 自驱动 Janus微球 受限 障碍物
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Innovative Education and Training in high power laser plasmas(PowerLaPs) for plasma physics, high power laser-matter interactions and high energy density physics-theory and experiments
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作者 John Pasley Georgia Andrianaki +35 位作者 Andreas Baroutsos Dimitri Batani Emmanouil PBenis Marco Borghesi Eugene Clark Donna Cook Emmanuel D'Humieres?,Vasilios Dimitriou Brendan Dromey Michael Ehret Ioannis Fitilis Anastasios Grigoriadis Satya Kar Evaggelos Kaselouris Ondrej Klimo Michel Koenig Kyriaki Kosma George Koundourakis Milan Kucharik Aveen Lavery Jiri Limpouch Yannis Orphanos Nektarios APapadogiannis Stelios Petrakis Dave Riley Maria Serena Rivetta Laura Tejada Pascual Joao Jorge Santos Alexandros Skoulakis Ioannis Tazes Vladimir Tikhonchuk Jocelain Treia Calliope Tsitou Luca Volpe Steven White Mark Yeung and Michael Tatarakis 《高功率激光科学与工程:英文版》 CAS CSCD 2019年第2期22-26,共5页
The Erasmus Plus programme’Innovative Education and Training in high power laser plasmas’,otherwise known as PowerLaPs,is described.The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre... The Erasmus Plus programme’Innovative Education and Training in high power laser plasmas’,otherwise known as PowerLaPs,is described.The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme where teaching takes place in five separate institutes with a range of different aims and styles of delivery.The ’in class’ time is limited to four weeks a year,and the programme spans two years.PowerLaPs aims to train students from across Europe in theoretical,applied and laboratory skills relevant to the pursuit of research in laserplasma interaction physics and inertial confinement fusion(ICF).Lectures are intermingled with laboratory sessions and continuous assessment activities.The programme,which is led by workers from the Technological Educational Institute(TEI)of Crete,and supported by co-workers from the Queen’s University Belfast,the University of Bordeaux,the Czech Technical-University in Prague,Ecole Polytechnique,the University of Ioannina,the University of Salamanca and the University of York,has just completed its first year.Thus far three Learning Teaching Training(LTT)activities have been held,at the Queen’s University Belfast,the University of Bordeaux and the Centre for Plasma Physics and Lasers(CPPL)of TEI Crete.The last of these was a two-week long Intensive Programme(IP),while the activities at the other two universities were each five days in length.Thus far work has concentrated upon training in both theoretical and experimental work in plasma physics,high power laser-matter interactions and high energy density physics.The nature of the programme will be described in detail and some metrics relating to the activities carried out to date will be presented. 展开更多
关键词 HIGHER EDUCATION INERTIAL CONFINEMENT fusion LASER-PLASMA interactions post-graduate EDUCATION
纳米限域的十四醇相变材料的相变行为研究
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作者 唐云雨 徐芬 +3 位作者 孙立贤 夏永鹏 陈冬梅 兰孝征 《化工新型材料》 CAS CSCD 北大核心 2019年第2期162-165,共4页
选取十四醇为相变材料、具有不同孔径的硅胶为载体,采用物理浸渍法制得十四醇/硅胶复合相变材料。借助差示扫描量热仪对限域的十四醇的相变行为进行表征。结果表明,限域的十四醇具有良好的热循环稳定性。随硅胶孔径的减小,限域的十四醇... 选取十四醇为相变材料、具有不同孔径的硅胶为载体,采用物理浸渍法制得十四醇/硅胶复合相变材料。借助差示扫描量热仪对限域的十四醇的相变行为进行表征。结果表明,限域的十四醇具有良好的热循环稳定性。随硅胶孔径的减小,限域的十四醇与硅胶孔壁的相互作用加强、其相变温度向低温方向移动。研究结果还表明通过纳米限域可对相变材料的相变温度进行调控;可实现将固-液相变材料制成定型相变材料,从而抑制相变材料的流失。 展开更多
关键词 十四醇 硅胶 相变材料 限域 物理浸渍
A test method for evaluating the thermal environment of underground coal mine refuge alternatives 预览
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作者 D.S.Yantek L.Yan +2 位作者 N.W.Damiano M.A.Reyes J.R.Srednicki 《矿业科学技术学报:英文版》 CSCD 2019年第3期343-355,共13页
Since 2009,the Mine Safety and Health Administration(MSHA)has required mines to install refuge alternatives(RAs)in underground coal mines.One of the biggest concerns with occupied RAs is the possible severity of the r... Since 2009,the Mine Safety and Health Administration(MSHA)has required mines to install refuge alternatives(RAs)in underground coal mines.One of the biggest concerns with occupied RAs is the possible severity of the resulting thermal environment.In 30 CFR 7.504,the maximum allowable apparent temperature(AT)for an occupied RA is specified as 35℃(95°F).Manufacturers must conduct heat/humidity tests to demonstrate that their RAs meet the 35℃(95°F)AT limit.For these tests,heat input devices are used to input the metabolic heat of actual miners.A wide variety of test methods,sensors,and heat input devices could be used when conducting such tests.Since 2012,the National Institute for Occupational Safety and Health(NIOSH)has conducted over thirty 96-hour heat/humidity tests on four different RAs.This paper discusses the test equipment and procedures used during these investigations.This information is useful for RA manufacturers conducting RA heat/humidity tests,for other researchers investigating RA heat/humidity buildup,and for those who need to assess the thermal environment of any confined space where people may be trapped or are seeking refuge. 展开更多
关键词 REFUGE CHAMBER REFUGE ALTERNATIVE CONFINED space THERMAL environment Test method Temperature
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海明威《雨中猫》中的时间与空间(英文)
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作者 李雯筑 《华中师范大学研究生学报》 2019年第1期7-12,共6页
通过对时间与空间进行特殊处理,'雨中猫'展现了一对夫妻之间感情疏离的故事。叙事学家里蒙·凯南将时间分成三个维度:时序,时限和叙述频率。文章将详细讨论这篇短篇小说中的时限和叙述频率。另一名叙事学家米克·巴尔... 通过对时间与空间进行特殊处理,'雨中猫'展现了一对夫妻之间感情疏离的故事。叙事学家里蒙·凯南将时间分成三个维度:时序,时限和叙述频率。文章将详细讨论这篇短篇小说中的时限和叙述频率。另一名叙事学家米克·巴尔认为视觉,听觉和触觉这三种感官参与了空间的呈现。此外,她还强调了空间与人物之间的关系,这也将在文章中得到进一步论述。通过巧妙地运用时间和空间这两种常见的叙事元素,小说的主题得以更好地体现。 展开更多
关键词 叙述频率 时限 空间 人物 约束
论儿童(期)的诞生 预览
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作者 戎庭伟 《泰山学院学报》 2019年第3期1-6,共6页
教育史上的“儿童(期)”是如何出现的?福柯式思维认为,儿童期的出现是文化人类学事件,它超越了单纯的生物学范畴,而成为论述空间中话语论述和制度实践的产物。论述空间本质为禁闭空间:其中,机构性禁闭让“儿童”成为一种问题域与社会资... 教育史上的“儿童(期)”是如何出现的?福柯式思维认为,儿童期的出现是文化人类学事件,它超越了单纯的生物学范畴,而成为论述空间中话语论述和制度实践的产物。论述空间本质为禁闭空间:其中,机构性禁闭让“儿童”成为一种问题域与社会资源,成为谈论与操控的对象;而话语性禁闭旨在建构儿童的时代特征,实现儿童与其生存于其中的社会的共构。经由这两种过程,儿童诞生了,专门围绕儿童的教育话语与实践活动出现并逐步发展。 展开更多
关键词 儿童(期) 话语 论述空间 禁闭 福柯
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Thermodynamics Properties of Confined Particles on Noncommutative Plane
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作者 Rachid Houca Ahmed Jellal 《理论物理通讯:英文版》 CSCD 2019年第9期1047-1053,共7页
We consider a system of N particles living on the noncommutative plane in the presence of a confining potential and study its thermodynamics properties. Indeed, after calculating the partition function, we determine t... We consider a system of N particles living on the noncommutative plane in the presence of a confining potential and study its thermodynamics properties. Indeed, after calculating the partition function, we determine the corresponding internal energy and heat capacity where different corrections are obtained. In analogy with the magnetic field case, we define an effective magnetization and study its susceptibility in terms of the noncommutative parameter θ.By introducing the chemical potential, we investigate the Bose-Einstein condensation for the present system. Different limiting cases related to the temperature and θ will be analyzed as well as some numerical illustration will be presented. 展开更多
关键词 CONFINING potential NONCOMMUTATIVE plane THERMODYNAMICS properties BOSE-EINSTEIN CONDENSATION
考虑深部赋存条件的岩石动态破坏试验研究进展 预览
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作者 夏开文 徐颖 陈荣 《隧道与地下工程灾害防治》 2019年第1期46-63,共18页
由于深部岩石处于高地应力、高地温、高渗透压的复杂地质环境下,现有的岩石力学理论已不能很好地解释深部岩石在开采、爆破或地震等动态荷载下的力学特性及破坏机理。近几十年来,国内外诸多学者对岩石动态力学开展了大量的室内试验研究... 由于深部岩石处于高地应力、高地温、高渗透压的复杂地质环境下,现有的岩石力学理论已不能很好地解释深部岩石在开采、爆破或地震等动态荷载下的力学特性及破坏机理。近几十年来,国内外诸多学者对岩石动态力学开展了大量的室内试验研究,在岩石的动态压缩、拉伸、断裂和剪切等基本力学特性方面取得了丰硕的成果。由于深部岩石所处地质环境的复杂性,这些岩石动力学的成果有待扩充以考虑深部岩石的特殊赋存环境的影响。结合已有的动力学研究方法,考虑高温、含水、以及原位应力对岩石动态力学特性的影响,是深部岩石工程的关键问题。对考虑深部赋存条件的高应力、高温和含水条件下岩石动态力学特性研究现状进行系统的总结,从试验系统原理、分析方法和试验结果 3个方面归纳针对深部赋存条件下岩石动态测试方法及其力学响应特性,并对深部岩石动态力学这一新兴的岩石力学研究方向进行展望。 展开更多
关键词 分离式霍普金森压杆 围压 温度 含水率 动态强度 动态断裂韧度
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