共查询到20条相似文献,搜索用时 15 毫秒
1.
基于有限元理论对阵列光纤和波导芯片粘接情况进行了建模与仿真,分析了在温度变化下不同粘接区域厚度的热应力和微位移的产生和分布,结果表明粘接界面的边缘区域对温度变化最敏感.根据光弹效应定性分析了粘接区域的应力双折射,并利用光束传播法计算了由此微位移所导致的光功率损耗,结果表明若以附加损耗小于0.15 dB的标准考察,则必须要求粘胶厚度的理论值在16 μm以内.总结了温度变化和在相同条件下不同粘胶厚度对平面光波导封装性能的影响规律. 相似文献
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A Method of Lines Based on Immersed Finite Elements for Parabolic Moving Interface Problems 下载免费PDF全文
This article extends the finite element method of lines to a parabolic
initial boundary value problem whose diffusion coefficient is discontinuous
across an interface that changes with respect to time. The method presented
here uses immersed finite element (IFE) functions for the discretization in
spatial variables that can be carried out over a fixed mesh (such as a
Cartesian mesh if desired), and this feature makes it possible to reduce
the parabolic equation to a system of ordinary differential equations (ODE)
through the usual semi-discretization procedure. Therefore, with a suitable
choice of the ODE solver, this method can reliably and efficiently solve a
parabolic moving interface problem over a fixed structured (Cartesian) mesh.
Numerical examples are presented to demonstrate features of this new method. 相似文献
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离散元与有限元结合的多尺度方法及其应用 总被引:11,自引:0,他引:11
在深入研究复杂结构和非均质材料冲击响应和破坏机理的过程中,往往遇到多尺度计算问题.提出并建立起离散元与有限元结合的多尺度方法,该方法采用离散元对感兴趣的局部进行细观尺度的模拟,利用有限元进行宏观的模拟,从而节约了计算时间.采用一种特殊的过渡层衔接离散元区和有限元区.将这一方法应用于激光辐照下预应力铝板的破坏响应,并将得到的模拟结果与实验进行了比较. 相似文献
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Mai Lu Zhide Hu Zheng Yang Fulin Wei 《International Journal of Infrared and Millimeter Waves》2000,21(6):965-977
In this paper, the electric field lines of the dominant mode in a closed V-groove guide as well as an open one are analysed by finite element method. The results show that the electric field lines are not parallel to the parallel plate region, but perpendicular to them. Since the attenuation increase with increasing frequency when the electric field lines are perpendicular to the mental walls, the V-groove is not suitable to be used in millimeter and submillimeter wavebands, and it is can't be regarded as low-loss wave guiding structures. 相似文献
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提出一种新型基于Si2N2O基体的LiNbO3行波调制器,利用有限元方法对该调制器进行数值分析并获得调制器的优化结构尺寸.该新型调制器带宽达到120 GHz,半波电压为3.5 V,特性阻抗为50.2 Ω.结果表明该调制器具有大的调制带宽和良好的阻抗匹配,在未来光通信中具有很好的应用前景. 相似文献
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Mai Lu Paul J. Leonard Zhide Hu Zheng Yang 《International Journal of Infrared and Millimeter Waves》2002,23(2):301-308
The single-mode bandwidth in rectangular-groove guides with different dimensions has been studied by finite element method. The actual single-mode bandwidth in a rectangular-groove guide is the same with a rectangular guide with the similiar dimensions. The dominant single-mode transmission in a rectangular-groove guide at millimetric waveband by adjusting the guide dimensions can only be an approximate one. 相似文献
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Discrete Maximum Principle Based on Repair Technique for Finite Element Scheme of Anisotropic Diffusion Problems 下载免费PDF全文
Xingding Chen Guangwei Yuan & Yunlong Yu 《advances in applied mathematics and mechanics.》2014,6(6):849-866
In this paper, we construct a global repair technique for the finite element scheme of
anisotropic diffusion equations to enforce the repaired solutions satisfying
the discrete maximum principle. It is an extension of the existing local
repair technique. Both of the repair techniques
preserve the total energy and are easy to be implemented. The numerical
experiments show that these repair techniques do not destroy the accuracy
of the finite element scheme, and the computational cost of the
global repair technique is lower than the local repair technique when the
diffusion tensors are highly anisotropic. 相似文献
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Mai Lu Fulin Wei Zhuoxiang Ren Zheng Yang 《International Journal of Infrared and Millimeter Waves》1999,20(4):645-654
The structure of closed trapezoidal-groove guide is similiar to that of open one, but it can be used to prevent energy from leaking out of the guide. In this paper, the propagation characteristics of dominant mode in closed trapezoidal-groove guide are analysed by using finite element method and the results are discussed. 相似文献
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Mai Lu Paul J. Leonard Duo-Wang Fan 《International Journal of Infrared and Millimeter Waves》2005,26(5):739-749
The electromagnetic power coupling in symmetrical and asymmetrical double circular-groove guides have been analyzed by finite element method (FEM) in this paper. The electrical field patterns of the dominant mode and the first higher-order TE mode have been presented. The electromagnetic field of the dominant mode distributes with a concentration in the two grooves and the region between grooves as well for symmetrical double circular-groove guide, while it distributes with a concentration in the groove with larger radius for the asymmetrical double circular-groove guide. The electrical field patterns of the first higher-order TE mode in symmetrical and asymmetrical double circular-groove guide are also presented. The figures in this paper have important values in design of circular-groove guide power coupler for millimeter wave applications. 相似文献
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R. S. Chen D. X. Wang Edward K. N. Yung 《International Journal of Infrared and Millimeter Waves》2002,23(2):275-293
The multifrontal method is applied for solving a large system of linear equations resulting from the use of edge-based finite element method (FEM). The finite element method combined with the perfectly matched layers (PML) is given for simulation of microwave filters and the algorithm of multifrontal method is described in detail. The reflection and insertion losses of millimeter wave filter are analyzed as the examples and the obtained results are compared with those obtained from literature. In order to demonstrate the efficiency of the multifrontal method, the computational time is compared with that of both symmetric successive overrelaxation (SSOR) preconditioned conjugate gradient (PCG) and conjugate gradient methods (CG) for the thick-iris waveguide bandpass filer. 相似文献
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The electromagnetic power coupling in asymmetrical double-groove guide is analyzed by finite element method (FEM) in this paper. The electrical field patterns of the dominant mode and the first higher-order TE mode have been presented. The electromagnetic field of the dominant mode is distributed with a concentration of energy in the wide groove region, while the electromagnetic field of the first higher-order TE mode is distributed with a concentration of energy in the narrow groove region. The results in this paper have important values in design of groove guide power coupler for millimeter wave applications. 相似文献
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Design of a Rectangular to Circular Groove Waveguide Transition by Finite Element Method 总被引:1,自引:0,他引:1
Yaozhong Xu Zhifang Qian Hongsheng Yang 《International Journal of Infrared and Millimeter Waves》2001,22(9):1381-1391
A rectangular to circular groove waveguide transition is described in millimeter-wave band. The transition maintains a constant cutoff wavelength. Using the Finite Element Method, the size of the variable cross-section throughout the transition are calculated and the transition is designed. 相似文献
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R. S. Chen K. F. Tsang Edward K. N. Yung 《International Journal of Infrared and Millimeter Waves》2000,21(8):1281-1301
In this paper, symmetric successive overrelaxation (SSOR) preconditioned CG technique are introduced into method of lines (MOL) to further enhance the computational efficiency of this semi-analytic method. Millimeter wave scattering by an infinite plane metallic grating is used as the examples to describe its implementation, whose analysis usually needs fast algorithms because of electrically large dimension. For arbitrary incident wave, Helmholz equation and boundary condition are used to calculate the impedance matrix and then to obtain reduced current-voltage linear matrix equation in spatial domain. An effective symmetric successive overrelaxation preconditioned conjugate gradient iterative method, SSOR-PCG, is chosen to solve this matrix equation. With SSOR as the preconditioner as well as its efficient implementing in CG algorithm, PCG method can converge to accurate solution in much fewer iteration steps. 相似文献
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研究了有限元方法在二维均匀结构和轴对称加速结构中的应用,采用了带宽优化技术和子空间求解特征值方法,并给出了部分例子,结果表明该方法精度高、速度快.这些方法可直接用于三维程序、并行计算. 相似文献
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This paper studies a system of semi-linear fractional diffusion equations
which arise in competitive predator-prey models by replacing the second-order derivatives
in the spatial variables with fractional derivatives of order less than two. Moving
finite element methods are proposed to solve the system of fractional diffusion equations
and the convergence rates of the methods are proved. Numerical examples are
carried out to confirm the theoretical findings. Some applications in anomalous diffusive
Lotka-Volterra and Michaelis-Menten-Holling predator-prey models are studied. 相似文献