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61.
Q. B. Li 《Optics and Lasers in Engineering》1989,11(2)
The smoothing spline function has been used for differentiation of photomechanical data in experimental stress analysis. However, since the available software packages use the algorithm with the so-called natural boundary conditions which are not necessarily suitable in many circumstances, errors tend to occur in both the first and second derivatives. In this paper we have modified the algorithm so that the user can have more freedom in selecting boundary conditions which suit the problem best and therefore, as a result, improve the accuracy of the analysis. Two examples are given to show the improvement achievable using the new scheme. 相似文献
62.
The mixed complex [Ni(L)(L')](ClO4)2 has been synthesized using 2-aminoethyl- bi(3-bi-aminopropyl)amine with phen (1,10-phenanthroline) in the presence of Ni(II) ion, and its structure was determined by X-ray diffraction. The crystal crystallizes in monoclinic, space group P21/c with a = 13.713(2), b = 13.1466(19), c = 14.780(2) (A), β = 97.620(3)°, V = 2640.9(7)(A)3, F(000) = 1272, Z = 4, Dc = 1.540 g/cm3, R = 0.0536 and wR = 0.1207. The Ni2+ ion is six- coordinated to furnish a distorted octahedral geometry. 相似文献
63.
Substructuring preconditioners for saddle-point problems arising from Maxwell's equations in three dimensions 总被引:1,自引:0,他引:1
This paper is concerned with the saddle-point problems arising from edge element discretizations of Maxwell's equations in a general three dimensional nonconvex polyhedral domain. A new augmented technique is first introduced to transform the problems into equivalent augmented saddle-point systems so that they can be solved by some existing preconditioned iterative methods. Then some substructuring preconditioners are proposed, with very simple coarse solvers, for the augmented saddle-point systems. With the preconditioners, the condition numbers of the preconditioned systems are nearly optimal; namely, they grow only as the logarithm of the ratio between the subdomain diameter and the finite element mesh size.
64.
在程序升温条件下 ,用DSC研究了标题化合物的放热分解反应动力学 .用线性最小二乘法、迭代法以及二分法与最小二乘法相结合的方法 ,以积分方程、微分方程和放热速率方程拟合DSC数据 .在逻辑选择建立了微分和积分机理函数的最可几一般表达式后 ,用放热速率方程得到相应的表观活化能 (Ea)、指前因子 (A)和反应级数 (n)的值 .结果表明 :该反应的微分形式的经验动力学模式函数、Ea 和A值分别为 (1-α) 0 .44、2 30 .4kJ/mol和 10 18.16s-1.借助加热速率和所得动力学参数值 ,提出了标题化合物放热分解反应的动力学方程 .该化合物的热爆炸临界温度为 30 2 .6℃ .上述动力学参数对分析、评价标题化合物的稳定性和热变化规律十分有用 . 相似文献
65.
A lithium(I) coordination polymer has been formed from LiClO4 and the 2,2′‐bipyrimidine (bpym) ligand in which each square pyramidal lithium(I) atom is coordinated in the basal plane by four nitrogen donor atoms derived from two bpym ligands and one water molecule at the apical position. These are connected into a layer structure via hydrogen‐bonding interactions involving the perchlorate anions. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
66.
Generation of UV laser light by stimulated Raman scattering in D2, D2/Ar and D2/He using a pulsed Nd:YAG laser at 355nm 下载免费PDF全文
A pulsed Nd:YAG laser at 355nm is used to pump Raman cell filled with D_2, D_2/Ar and D_2/He. With adequately adjusted parameters, the maximum photon conversion efficiency of the first-order Stokes light (S_1, 396.796nm) reaches 33.33% in D_2/Ar and the stability of S_1 in pure D_2 is fairly high, the energy drift being less than 10% when the pump energy drifts in the range of 5%. The conversion efficiency and stability, which are functions of the composition and pressure of the Raman medium and the energy of pump laser, are investigated. The result has been used to optimize the laser transmitter system for a differential absorption lidar system to measure NO_2 concentration profiles. 相似文献
67.
D. Liu N.Q. Ngo X.Y. Dong S.C. Tjin P. Shum 《Applied physics. B, Lasers and optics》2005,81(6):807-811
We propose and experimentally demonstrate a stable dual-wavelength erbium-doped polarization-maintaining (PM) fiber laser
with tunable wavelength spacing using an all-PM linear cavity that makes use of two reflection peaks from the PM fiber Bragg
grating (PM-FBG). Experimental results show stable dual lasing lines with a wavelength separation of ∼0.22 nm and a large
optical signal-to-noise ratio (OSNR) of over 40 dB under room temperature. By applying axial strain to the PM-FBG, the center
wavelengths of the two lasing lines can be tuned over several nanometers and the wavelength separation between the lasing
lines can also be tuned to as small as 0.05 nm, which, to our knowledge, is the smallest wavelength spacing ever obtained
from a stable room-temperature dual-wavelength fiber laser. The proposed laser configuration has the advantages of simple
structure, low loss, stable dual-wavelength operation and a very small lasing linewidth of ∼5 kHz .
PACS 42.55.Wd; 42.81.-i; 42.81.Gs 相似文献
68.
69.
We present some algorithms related to rings of Ore polynomials (or, briefly, Ore rings) and describe a computer algebra library
for basic operations in an arbitrary Ore ring. The library can be used as a basis for various algorithms in Ore rings, in
particular, in differential, shift, and q-shift rings.
__________
Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 13, Algebra,
2004. 相似文献
70.
本文提出从高分辨电子显微像中,利用光学、全息和部分相干等方法,提取传递函数,制作相位和振幅滤波器,实现解卷,提高高分辨电子显微像的分辨率. 相似文献