排序方式: 共有39条查询结果,搜索用时 15 毫秒
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高压下某些导电高分子色散关系的研究 总被引:1,自引:0,他引:1
利用晶格动力学方法,研究在高压下几种导电高分子具有不同晶格链时的色散关系及其曲线的变化.链间耦合作用的减弱使横波与纵波的ω差值相应增大,且在BZ边界处拉开一个间隙,这是维度作用的结果. 相似文献
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X射线衍射摇摆曲线的计算机模拟是一种获得材料晶体质量参量的有效方法,其中材料本征摇摆曲线的计算是计算机模拟的基础。用X射线动力学理论计算了Hg1-xCdxTe和Cd1-zZnzTe本征反射率曲线,并研究了组分、膜厚分别对本征反射率和半峰全宽的影响。结果表明Hg1-xCdxTe和Cd1-zZnzTe的本征反射率和半峰全宽与材料组分和厚度有明显的依赖关系,且该依赖关系取决于X射线在材料中的散射和吸收的相对强弱。薄膜的厚度也是直接影响本征摇摆曲线峰形、半峰全宽和反射率的重要因素,当薄膜厚度小于穿透深度时,表征本征反射率曲线的各个参量均与薄膜厚度有直接的关系。对于(333)衍射面,碲镉汞材料厚度大于7μm后,本征反射率和半峰全宽将不再发生明显变化。 相似文献
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利用模态综合法分析车辆与桥梁之间的相互作用时,合理地构造桥梁的插值振型函数可以大幅提高计算精度.其中,分段三次Hermite插值函数和三次样条插值函数较为常用.为研究二者的异同,以简支梁桥为例分别采用这两种插值函数构造结构梁单元模型的一维插值振型函数和板单元模型的二维插值振型函数.基于以上两类插值振型函数,分析单自由度簧上质量匀速过桥时,桥梁的跨中位移、跨中梁底正应力和轮-桥接触力时程响应.结果表明:无论是一维问题还是二维问题,由三次样条插值法构造的插值振型函数与结构的实际振型较为吻合,计算结果具有较高的收敛性和精度.而要达到相同的精度,分段三次Hermite插值法则须加密单元网格,但其误差仅存在于独立网格内,不会累积放大. 相似文献
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Soliton solution and interaction property for a coupled modified Korteweg-de Vries (mKdV) system
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Hirota's bilinear direct method is applied to constructing soliton solutions to a special coupled modified Korteweg- de Vries (mKdV) system. Some physical properties such as the spatiotemporal evolution, waveform structure, interactive phenomena of solitons are discussed, especially in the two-soliton case. It is found that different interactive behaviours of solitary waves take place under different parameter conditions of overtaking collision in this system. It is verified that the elastic interaction phenomena exist in this (1+1)-dimensional integrable coupled model. 相似文献
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Residual symmetry reductions and interaction solutions of the (2+1)-dimensional Burgers equation
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In nonlinear physics,it is very difficult to study interactions among different types of nonlinear waves.In this paper,the nonlocal symmetry related to the truncated Painleve′expansion of the(2+1)-dimensional Burgers equation is localized after introducing multiple new variables to extend the original equation into a new system.Then the corresponding group invariant solutions are found,from which interaction solutions among different types of nonlinear waves can be found.Furthermore,the Burgers equation is also studied by using the generalized tanh expansion method and a new Ba¨cklund transformation(BT)is obtained.From this BT,novel interactive solutions among different nonlinear excitations are found. 相似文献
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We obtain the non-local residual symmetry related to truncated Painlev′e expansion of Burgers equation. In order to localize the residual symmetry, we introduce new variables to prolong the original Burgers equation into a new system.By using Lie’s first theorem, we obtain the finite transformation for the localized residual symmetry. More importantly,we also localize the linear superposition of multiple residual symmetries to find the corresponding finite transformations.It is interesting to find that the n-th B¨acklund transformation for Burgers equation can be expressed by determinants in a compact way. 相似文献
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根据变系数modified Korteweg-de Vries(VCmKdV)方程与常系数KdV-mKdV方程的非线性项、色散项的相似性,对解已知的KdV-mKdV方程做适当变换,并将它的解移植到解未知的VCmKdV方程,由此构造出两个不同方程解之间的移植关系.利用这种解的移植方法,求得了由两层流体模型经演化获得的含有源(或汇)耦合VCmKdV系统新的精确解和类孤波解.对Bcklund变换与解的移植法进行了比较,分析了源和汇对波幅的影响.
关键词:
解的移植法
KdV-mKdV方程
耦合VCmKdV系统
类孤波解 相似文献
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基于在任意坐标系内应力与应变的关系、晶体弹性理论和位错滑移理论,研究了生长方向分别为[111]和[211]晶向,HgCdTe外延薄膜临界厚度与CdZnTe衬底中Zn组分和HgCdTe外延层中Cd组分的关系. 结果表明,HgCdTe外延薄膜临界厚度依赖于CdZnTe衬底中Zn组分和HgCdTe外延层中Cd组分的变化. 对于厚度为10μm,生长方向为[111]晶向的液相外延HgCdTe薄膜,要确保HgCdTe/CdZnTe无界面失配位错的前提条件,是CdZnTe衬底中Zn组分和HgCdTe外延层中Cd组分的波动必须分别在±0.225‰和±5‰范围内;而对于相同厚度,生长方向为[211]晶向的分子束外延HgCdTe薄膜,CdZnTe衬底中Zn组分和HgCdTe外延层中Cd组分的波动范围分别为±0.2‰和±4‰.
关键词:
HgCdTe/CdZnTe
临界厚度
位错滑移理论
失配位错 相似文献