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51.
52.
推导出了部分相干双曲余弦高斯光束在自由空间和湍流大气中传输瑞利区间的解析公式,并研究了湍流对光束瑞利区间的影响.研究表明,部分相干双曲余弦高斯光束的瑞利区间由湍流强度和光束参数等因数共同确定.湍流使得光束的瑞利区间缩短,并且湍流越强瑞利区间越短.在自由空间中,瑞利区间随光束相干参数 α 、光束参数 β 和高斯束宽 w 0的增大以及波长 λ 的减小而增大.但是, α,β 和 w 0越小以及 λ 越大,瑞利区间受湍流的影响越小.并且,当
关键词:
瑞利区间
部分相干双曲余弦高斯光束
大气湍流
自由空间 相似文献
53.
K. Mohammed Jasim 《Optics and Lasers in Engineering》2011,49(7):785-792
The present paper reports an experimental investigation based on X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and wavelength dispersive spectroscopy (WDS) analyses of phases formed after laser sealing of plasma sprayed coatings of 8.5 wt% yttria partially stabilized zirconia (YPSZ). X-ray diffraction and X-ray step-scanning analyses showed that the plasma sprayed and sealed coatings consisted mainly of t′ phase with a very small amount of monoclinic phase (m phase) in the plasma sprayed coatings. It was also found that the small amounts of m and cubic phases (c phase) present in the sealed coatings were dependent on laser processing specific energies (specific energy is equal to laser power/traverse speed x beam diameter). It was also found that rhombohedral (r) phase formed after laser sealing of coatings at higher specific energies. A direct relationship between c/a ratio of transformable tetragonal phase (t phase) produced by thermal treatment of sealed coatings and nontransformable tetragonal phase (t′ phase) and the amount of Yttria was obtained. A new equation was derived, which describes the relationship between Yttria concentration and the c/a ratio of tetragonal phases (t or t′). 相似文献
54.
In this article, we develop a partially penalty immersed interface finite element (PIFE) method for a kind of anisotropy diffusion models governed by the elliptic interface problems with discontinuous tensor‐coefficients. This method is based on linear immersed interface finite elements (IIFE) and applies the discontinuous Galerkin formulation around the interface. We add two penalty terms to the general IIFE formulation along the sides intersected with the interface. The flux jump condition is weakly enforced on the smooth interface. By proving that the piecewise linear function on an interface element is uniquely determined by its values at the three vertices under some conditions, we construct the finite element spaces. Therefore, a PIFE procedure is proposed, which is based on the symmetric, nonsymmetric or incomplete interior penalty discontinuous Galerkin formulation. Then we prove the consistency and the solvability of the procedure. Theoretical analysis and numerical experiments show that the PIFE solution possesses optimal‐order error estimates in the energy norm and norm.© 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1984–2028, 2014 相似文献
55.
光源编码的白光散斑剪切干涉计量术 总被引:3,自引:1,他引:2
本文提出了一种用非相干光源照明进行剪切干涉计量的方法—光源编码的白光散斑剪切干涉计量术.它采用光栅对光源进行编码以提高空间相干性,使物体的两个剪切像的波面部分相干叠加,以实现剪切干涉. 相似文献
56.
Du Beiliang 《高校应用数学学报(英文版)》2007,22(2):169-173
A strong partially balanced design SPBD(v, b, k; λ,0) whose b is the maximum number of blocks in all SPBD(v, b, k; λ, 0), as an optimal strong partially balanced design, briefly OSPBD(v, k, λ) is studied. In investigation of authentication codes it has been found that the strong partially balanced design can be used to construct authentication codes. This note investigates the existence of optimal strong partially balanced design OSPBD(v, k, 1) for k = 3 and 4, and shows that there exists an OSPBD(v, k, 1) for any v ≥ k. 相似文献
57.
We integrate the equations of gas dynamics in finite form for the solutions in which the thermodynamic parameters depend only on one spatial variable. The corresponding motion of gas represents the nonlinear superposition of the one-dimensional gas motion corresponding to the invariant system and the two-dimensional motion determined by noninvariant functions. These motions are called 2.5-dimensional. We reduce the invariant system to a first-order implicit ordinary differential equation. We study various solutions of the latter. We construct some continuous and discontinuous solutions to the equations of gas dynamics and give their physical interpretation. 相似文献
58.
部分线性模型也就是响应变量关于一个或者多个协变量是线性的, 但对于其他的协变量是非线性的关系\bd 对于部分线性模型中的参数和非参数部分的估计方法, 惩罚最小二乘估计是重要的估计方法之一\bd 对于这种估计方法, 广义交叉验证法提供了一种确定光滑参数的方法\bd 但是, 在部分线性模型中, 用广义交叉验证法确定光滑参数的最优性还没有被证明\bd 本文证明了利用惩罚最小二乘估计对于部分线性模型估计时, 用广义交叉验证法选择光滑参数的最优性\bd 通过模拟验证了本文中所提出的用广义交叉验证法选择光滑参数具有很好的效果, 同时, 本文在模拟部分比较了广义交叉验证和最小二乘交叉验证的优劣. 相似文献
59.
Existence and Uniqueness of Fixed Point in Partially Ordered Sets and Applications to Ordinary Differential Equations 总被引:1,自引:0,他引:1
We prove some fixed point theorems in partially ordered sets, providing an extension of the
Banach contractive mapping theorem. Having studied previously the nondecreasing case, we consider
in this paper nonincreasing mappings as well as non monotone mappings. We also present some
applications to first–order ordinary differential equations with periodic boundary conditions, proving
the existence of a unique solution admitting the existence of a lower solution.
Research partially supported by Ministerio de Educación y Ciencia and FEDER, Project MTM2004-06652-C03-01, and by Xunta de
Galicia and FEDER, Projects PGIDIT02PXIC20703PN and PGIDIT05PXIC20702PN 相似文献
60.
部分相干像面散斑技术 总被引:2,自引:0,他引:2
本文以光的部分相干性理论为指导,讨论了部分相干像面散斑(通常称为白光散斑)技术的关键.其结果可与激光像面散斑媲美. 相似文献