共查询到19条相似文献,搜索用时 78 毫秒
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二维声光互作用理论及实验分析 总被引:1,自引:3,他引:1
本文在理论上推导了二维声光互作用的耦合波方程的普适形式,并借以对正常声光互作用下的喇曼-奈斯(Raman-Nath)型衍射进行了求解,所得结果与两个一维喇曼-奈斯型声光调制器组成的两维器件的实验结果进行比较,两者相符. 相似文献
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本文在理论上给出了对二维R-N(喇曼-奈斯)型声光作用的光学双稳系统普遍适用的动态方程,并由此导出了该声光光学双稳系统的稳态解,借助于计算机给出了取(1,0)级作为反馈级次情况下的几个级次输入~输出关系曲线,并对此进行了稳定性分析;在实验上对该理论进行了验证,实验结果与理论相符. 相似文献
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短峰波和海流广泛分布于海洋之中,但二者的相互作用直到近些年才逐渐受到关注,根据速度势函数理论,推导二维均匀流与重力短峰波的相互作用,区别于之前的研究,推导时不考虑波面的毛细影响,避免了将位置变量(x)与时间变量(t)绑定的假设,使得二阶速度势函数包含了的时间(t)一阶项,从而给出了完整的二维流与短峰波交互作用的二阶解析解,对比结果说明上述考虑对于波流共同作用结果有影响,尤其是在波高较大时,影响更加明显,所得结果,可用于高波浪条件下海洋波浪与流相互作用的计算. 相似文献
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在平均场理论基础上,研究了具有DzyaloshinskiiMoriya(缩写为DM)相互作用的二维spinPeierls模型以及DM相互作用对二聚化的影响.研究表明,随模型参量的不同,DM相互作用能加强或削弱二聚化位移.另外,发现DM相互作用对二聚化位移的依赖程度参量λ存在一个特殊点λc,当λ=λc时,DM相互作用对二聚化没有影响.随晶格弹性系数的增加,λc将增大,而链间耦合将使λc减小
关键词:
二维spinPeierls模型 DM相互作用 相似文献
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定义了压电晶体的增劲声光系数,它反映压电晶体中声光、电光和压电效应共同作用的结果。从参量互作用基本理论出发,同时考虑声光效应、电光效应和压电效应三个因素,用一个压电增劲声光系数来表示三种因素的共同作用,导出表面波声光布拉格互作用的耦合波方程。并求解得出相应衍射效率的计算公式。该式说明在弱声光互作用条件下,衍射导光波强度与超声功率成正比。表面波声光器件具有体积小、工作稳定、能耗小、易于集成等优点。可以用作光偏转器、光调制器、滤光器。在光通信以及各类实时信号处理,如相关、卷积、频谱分析、矩阵光计算等领域具有广泛的应用前景。 相似文献
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我们提出了二维自相似变换理论,以聚焦的(2+1)维NLS方程(数学称为抛物型的非线性微分方程)为模型,构建了它被转变为聚焦的(1+1)维NLS方程的二维自相似变换,深入研究了它的空间怪波激发,发现除了(1+1)维NLS方程的Peregrine孤子、高阶怪波和多怪波诱导的线怪波所具有的短寿命特征外,由Akhmediev呼吸子(AB)和Kuznetsov-Ma孤子(KMS)诱导的线怪波也具有这种短寿命特征.这与由亮孤子(包括多孤子)诱导的空间相干结构保持形状和幅值不变的演化特征完全不同.通过图示展现了本文例举的各类线怪波的演化规律.本文揭示的线怪波激发新机制,有助于提升对高维非线性波动模型的相干结构的新认识. 相似文献
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硅基二维光子晶体耦合器理论研究 总被引:8,自引:4,他引:4
光子晶体是一种具有光子带隙的新型人工材料,利用其具有控制和限制光子运动的特性可以制成新颖的光学器件。利用硅基二维光子晶体,提出了一种4端口耦合器。采用时域有限差分法作为研究工具,TM模作为研究对象,从理论上分析了这种器件的特性。在不同的耦合长度下研究光在输出端的功率透射率。结果表明选择适当的耦合长度可以使光在器件中呈现不同的状态。进一步研究表明,通过改变器件内部介质柱的半径,可以改变光在输出端的输出功率。从而证实了这种器件不仅具有波长选择性,而且具有潜在的可调节性,这些特性使得这种器件在全光开关的应用上具有潜在的优势。 相似文献
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The features of noncollinear acousto-optic interaction in gyrotropic crystals in the intermediate diffraction regime and the
regime of Bragg diffraction were investigated. The dependence of the efficiency of diffraction in gyrotropic paratellurite,
tellurium, and quartz crystals on the intensity of the ultrasonic wave, acousto-optic interaction length, and incident-light
polarization was investigated. It is shown that the gyrotropy of the crystal is responsible for the appearance of a multiple-peak
structure of the Bragg maximum. It has been established that in the case of propagation of incident and diffracted waves in
the vicinity of the optical axis of the crystal, the diffraction efficiency is independent of the polarization state of the
incident light. The results of theoretical calculations are in agreement with the experimental results obtained for uniaxial
crystals.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 1, pp. 105–110, January–February, 2000. 相似文献
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The use of high-bypass-ratio engines in civil aviation has resulted in the occurrence of an additional noise source associated with noise of interaction between a jet and an airplane wing. A theoretical model is proposed for predicting the characteristics of interaction noise based on the near-field parameters for an isolated jet. The required near-field characteristics were obtained experimentally in the AC-2 anechoic chamber of the Central Aerohydrodynamic Institute (TsAGI) using a system of azimuthal microphone arrays. Noise in the far-field zone was also measured for both an isolated jet and a jet with a closely located plate simulating a wing. The results of comparing the directivities and spectra of interaction noise obtained using the proposed model and measured experimentally are in good agreement. 相似文献
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CAO Jian-Li ZHANG Hua JIAO Wan-Tang 《理论物理通讯》2008,49(6):1379-1382
Based on the second integrable ease of known two-dimensional Hamiltonian system with a quartie potentiM, we propose a 4 × 4 matrix speetrM problem and derive a hierarchy of coupled KdV equations and their Hamiltonian structures. It is shown that solutions of the coupled KdV equations in the hierarchy are reduced to solving two compatible systems of ordinary differentiM equations. As an application, quite a few explicit solutions of the coupled KdV equations are obtained via using separability for the second integrable ease of the two-dimensional Hamiltonian system. 相似文献
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New exact solutions expressed by the Jacobi elliptic functions are obtained to the long-short wave interaction equations by using the modified F-expansion method. In the limit case, solitary wave solutions and triangular periodic wave solutions are obtained as well. 相似文献