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Deformation Nano-Mechanisms Occurring on the Interface of Dissimilar Materials Joined in Solid Phase by Means of High Temperature Rolling
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作者 Boris V. Borts Nikolay I. Danilenko +4 位作者 Aleksander A. Parkhomenko Viktor I. Tkachenko Irina M. Korotkova Igor O. Vorobyov Aleksander T. Lopata 《Open Journal of Metal》 2014年第4期107-111,共5页
Nano-mechanisms of crystal lattice deformation on the interface of dissimilar materials (Cu-Nb), joined by vacuum rolling in solid phase under high temperature (950℃) were studied by means of high resolution electron... Nano-mechanisms of crystal lattice deformation on the interface of dissimilar materials (Cu-Nb), joined by vacuum rolling in solid phase under high temperature (950℃) were studied by means of high resolution electron microscopy. Input of carriers of rotation modes—nano-dipoles of partial disclinations and nano-twist disclinations in the form of double spirals in deformation mechanisms were analyzed. The role of these mechanisms in decrease of shear stability of the interface areas and in production of high-quality rolled metal is discussed. 展开更多
关键词 Vacuum Hot ROLLING Solid Phase INTERFACE Cupper-Niobium Microscopy disclinations
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Defect Core Structures in Twisted Nematic and Twisted Chiral Liquid Crystals
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作者 Xuan Zhou Guili Zheng Zhidong Zhang 《Journal of Modern Physics》 2013年第2期272-279,共8页
The defect structures of s = ±1/2 twist disclinations in twisted nematic and twisted chiral liquid crystals have been investigated within the Landau-de Gennes theory numerically. Our results show that there exist... The defect structures of s = ±1/2 twist disclinations in twisted nematic and twisted chiral liquid crystals have been investigated within the Landau-de Gennes theory numerically. Our results show that there exists eigenvalue exchange across the defect core of both the two models. The defect core is essentially biaxial and never isotropic. The defect centre is uniaxial and is surrounded by a strong biaxial region. 展开更多
关键词 disclinations EIGENVALUE Exchange DEFECT Core Landau-de Gennes Theory
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MECHANICAL PERTURBATION INDUCED MOLECULAR ALIGNMENTS IN A SIDE-CHAIN LIQUID CRYSTALLINE POLYACETYLENE, POLY{10-[4-(4'-METHOXYPHENOXY-CARBOML)PHENOXYCARBONYL]-1-DECYNE}
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作者 Ben-zhong Tang Xiang-xing Kong Xin-de Feng Department of Chemistry, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China Department of Polymer Science & Engineering, College of Chemistry, Peking University, Beijing 100871, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1999年第3期289-294,共6页
A new liquid crystalline polyacetylene containing a phenyl benzoate mesogen (5) is synthesized,whose mesomorphic properties are found to be easily 'tunab1e' by simple mechanical perturbation. Thepolymerization... A new liquid crystalline polyacetylene containing a phenyl benzoate mesogen (5) is synthesized,whose mesomorphic properties are found to be easily 'tunab1e' by simple mechanical perturbation. Thepolymerization of 10- [ 4 - (4' -methoxyphenoxycarbonyl )phenoxycarbonyl] - 1 -decyne (4 ) in itiated by theWCl_6-Ph_4Sn/dioxane complex yields polymer 5 with a M_w of 28400. The molecular structure of 5 ischaracterized by NMR, IR, and UV spectroscopy and its liquid crystalline behavior is investigated by DSC,POM, and XRD analysis. Upon mechanical perturbation, 5 exhibits unusual agitation-induced high-strengthdisclinations, shear-induced inversion walls, and solidification-induced banded textures. Such phenomenahave been observed in the main-chain liquid crystalline polymers with rigid backbones, but have seldom beenreported for the side-chain liquid crystalline polymers with flexible backbones, suggesting that the rigidpolyacetylene backbone of 5 plays a constructive role in inducing the novel molecular alignments. 展开更多
关键词 Liquid crystals Side-chain liquid crystalline polymers POLYACETYLENES High-strength disclinations Inversion walls Banded textures Molecular alignments
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Topological aspect of disclinations in two-dimensional crystals
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作者 齐维开 朱涛 +1 位作者 陈勇 任继荣 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第3期1002-1008,共7页
By using topological current theory, this paper studies the inner topological structure of disclinations during the melting of two-dimensional systems. From two-dimensional elasticity theory, it finds that there are t... By using topological current theory, this paper studies the inner topological structure of disclinations during the melting of two-dimensional systems. From two-dimensional elasticity theory, it finds that there are topological currents for topological defects in homogeneous equation. The evolution of disclinations is studied, and the branch conditions for generating, annihilating, crossing, splitting and merging of disclinations are given. 展开更多
关键词 topological current theory disclinations two-dimensional crystals
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乙基氰乙基纤维素溶致液晶的缺陷结构观察 被引量:1
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作者 黄勇 《纤维素科学与技术》 CAS CSCD 1993年第4期11-16,共6页
乙基氰乙基纤维素在许多溶剂中都可以形成胆甾型液晶溶液。在液晶溶液中出现多种向错结构。本文利用偏光显微镜和电子显徽镜对液晶溶液中出现的向错结构进行了全面的观察。观察到了λ,τ和x向错线以及各种由具有相反符号的λ和τ向错线... 乙基氰乙基纤维素在许多溶剂中都可以形成胆甾型液晶溶液。在液晶溶液中出现多种向错结构。本文利用偏光显微镜和电子显徽镜对液晶溶液中出现的向错结构进行了全面的观察。观察到了λ,τ和x向错线以及各种由具有相反符号的λ和τ向错线组成的向错对,其结构特征与小分子胆甾型液晶相结构特征相似。 展开更多
关键词 纤维素 液晶 向错结构 缺陷
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断层向错引起的地表重力变化研究 被引量:1
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作者 段虎荣 崔进业 杨凡 《大地测量与地球动力学》 CSCD 北大核心 2016年第9期761-765,共5页
利用三维角点法以及空间物体旋转的几何变换理论,建立断层向错与地表重力变化的关系,并进行数值模拟计算。选取断层下盘左端点为旋转基点,分析断层埋深和倾角对其向错引起的重力变化的影响。结果表明,断层向错引起的重力变化与断层埋深... 利用三维角点法以及空间物体旋转的几何变换理论,建立断层向错与地表重力变化的关系,并进行数值模拟计算。选取断层下盘左端点为旋转基点,分析断层埋深和倾角对其向错引起的重力变化的影响。结果表明,断层向错引起的重力变化与断层埋深有明显的相关性,在W1、W2、W3向错模式下,重力变化均表现为随断层深度增加而逐渐衰减;重力变化对断层倾角有着不同的响应。断层运动产生的重力变化空间分布特征与断层的向错模式以及旋转基点的选择有关。 展开更多
关键词 向错 重力变化 断层倾角 三维角点法
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铅垂断层向错引起的地表重力变化 被引量:1
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作者 段虎荣 杨凡 《大地测量与地球动力学》 CSCD 北大核心 2015年第4期627-631,共5页
利用直立长方体组合模型以及坐标旋转理论,对铅垂断层向错引起的重力变化进行数值模拟,分别计算深度为1、5、10km的铅垂断层在单一方向上、两个方向上向错引起的地面重力变化。结果表明,当断层在单一方向产生向错时,以左端点为基点的W1... 利用直立长方体组合模型以及坐标旋转理论,对铅垂断层向错引起的重力变化进行数值模拟,分别计算深度为1、5、10km的铅垂断层在单一方向上、两个方向上向错引起的地面重力变化。结果表明,当断层在单一方向产生向错时,以左端点为基点的W1、W2向错引起的地面重力变化场均呈现以断层为轴线的对称分布;以中点为基点的W3向错引起的地面重力变化场构成四象限反对称分布。当断层在两个方向上同时产生向错时,以左端点为基点的W1W2向错引起的地面重力变化场呈现以断层为轴线的对称分布,整体显示W2向错起主导作用;以中点为基点的W2W3向错引起的地面重力变化场呈现非对称分布,整体也显示出W2向错起主导作用,断层附近的扭错现象为W3向错的作用。随着断层深度的增加,断层向错引起的地面重力变化值递减,但影响范围逐渐扩大。 展开更多
关键词 向错 铅垂断层 重力变化 直立长方体组合模型
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矩形断层向-位错引起的空间重力变化
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作者 焦佳爽 张永志 +2 位作者 姜永涛 杨珍 张凯南 《测绘科学》 CSCD 北大核心 2015年第12期27-30,43,共5页
针对位错理论难以解释断层面之间的旋转转动的问题,该文基于子断层叠加法,利用经典点源位错理论,得出了矩形断层向-位错引起的空间重力变化。利用C++语言编制了弹性半空间中的矩形断层向-位错正演程序,模拟计算并分析了倾角为90°... 针对位错理论难以解释断层面之间的旋转转动的问题,该文基于子断层叠加法,利用经典点源位错理论,得出了矩形断层向-位错引起的空间重力变化。利用C++语言编制了弹性半空间中的矩形断层向-位错正演程序,模拟计算并分析了倾角为90°的矩形断层滑动和转动引起的空间重力变化的分布特征。数值模拟结果显示:断层运动引起的空间重力变化与断层的滑动和转动量大小及断层产状有关,断层滑动和转动越大,引起的地表变形范围和量值就越大;断层转动引起的重力变化大小与断层埋深成反关系,即断层埋深越大,相应的重力变化量值就越小;宏观上,矩形断层位错运动引起的重力变化呈近似对称的特征,而断层向错打破了重力变化图像的对称性。 展开更多
关键词 断层转动 空间重力变化 位错 向错
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Role of Disclinations and Nanocrystalline State in the Formation of Quasicrystalline Phases on Mechanical Alloying of Cu-Fe Powders
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作者 R.Subramanian and S.S.Raznakrishnan (Department of Metallurgy, P.S.G. College of Technology, Coimbatore-641004, Tamilnadu, India) P.Shankar+ (Materials Charasterisation Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, Tamilnadu, India) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第5期499-503,共5页
Elemental powders of Cu and Fe were ball milled for various time durations up to 100 h. The various stages of forced alloying by ball milling, leading to instability of elemental crystalline phases and formation of qu... Elemental powders of Cu and Fe were ball milled for various time durations up to 100 h. The various stages of forced alloying by ball milling, leading to instability of elemental crystalline phases and formation of quasicrystalline phases were monitored using X-ray diffraction. Diffusion of Fe into the Cu matrix is proposed as the cause which triggers the instability of crystalline phases and leads to the formation of quasicrystalline phases after 10 h of milling. Milling for 100 h resulted in two different quasicrystalline phases with different lattice constants. Role of the nanocrystalline microstructure as an important criterion for the destabilisation of crystalline phases is explained. It is suggested that the formation of nanocrystalline microstructure and their subsequent transformation into quasicrystalline phases may be associated with a continuous increase in the disclination content of the system, which had formed as a result of continued milling and mechanical deformation. 展开更多
关键词 Fe Role of disclinations and Nanocrystalline State in the Formation of Quasicrystalline Phases on Mechanical Alloying of Cu-Fe Powders Cu
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Topological bound states in elastic phononic plates induced by disclinations
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作者 Baizhan Xia Zihan Jiang +2 位作者 Liang Tong Shengjie Zheng d Xianfeng Man 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第2期154-164,I0005,共12页
Topological defects(including disclinations and dislocations)which commonly exist in various materials have shown an amazing ability to produce excellent mechanical and physical properties of matters.In this paper,dis... Topological defects(including disclinations and dislocations)which commonly exist in various materials have shown an amazing ability to produce excellent mechanical and physical properties of matters.In this paper,disclinations are introduced into topological nontrivial elastic phononic plates.The deformation of the lattice yielded by disclinations produces a pentagonal core with the local five-fold symmetry.The topological bound states are well localized around the boundaries of the pentagonal cores with and without hollow regions.The topological bound states immunize against the finite sizes and the moderate imperfects of plates,essentially differing from the trivial defect states.The discovery of topological bound states unveils a new horizon in topological mechanics and physics,and it provides a novel platfonn to implement large-scale elastic devices with topologically protected resonances. 展开更多
关键词 Elastic phononic plate disclinations Topological bound states Wannier centers
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