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251.
252.
In this paper, a sinusoidal phase-modulating Fabry-Perot interferometer is proposed to measure angular displacement.The usefulness of the interferometer is demonstrated by simulations and experiments.  相似文献   
253.
Two new polyacid derivative ligands of thienyl-substituted terpyridine analogues, N,N,N1,N1-[4′-(2?-thienyl)-2,2′:6′,2″-terpyridine-6,6″-diyl]bis(methylenenitrilo) tetrakis(acetic acid) (TTTA) and N,N,N1,N1-[2,6-bis(3′-aminomethyl-1′-pyrazolyl)-4-(2″-thienyl)pyridine] tetrakis(acetic acid) (BTTA), were synthesized, and the luminescence properties of their Eu3+ and Tb3+ chelates were investigated. The Eu3+chelates of the two ligands are strongly luminescent having luminescence quantum yields of 0.150 (TTTA-Eu3+) and 0.114 (BTTA-Eu3+), and lifetimes of 1.284 ms (TTTA-Eu3+) and 1.352 ms (BTTA-Eu3+), whereas their Tb3+ chelates are weakly luminescent. The TTTA-Eu3+ chelate was used for streptavidin (SA) labeling, and the labeled SA was used for time-resolved fluoroimmunoassay of insulin in human sera. The method gives the detection limits of 33 pg ml−1.  相似文献   
254.
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   
255.
投资理论告诉人们,应尽量使投资分散化.但许多投资在实际投资中却常常违背这一原则.本从一个调面分析在一个等均值和有一个无风险资产的均方世界里,交易成本的存在,会使投资产生很强的违背分散化原则的动机。  相似文献   
256.
This paper is a contionuation of [1] and is concerned with multiplication of weak functions. Here the weak functions are treated as generalized expansions in Hermite functions in [2].  相似文献   
257.
Millimeter-sized molybdenum nitride (MoN), in the forms of fiber-like prisms or hollow tubes, has been successfully synthesized via thermal ammonolysis of molybdenum polysulfide precursor. The initial morphology of the precursor is well preserved in the final product. This method could be expanded to preparation of other fiber-like nonmetal ceramics without addition of template. The polysulfide precursor (abbreviated to PS), hydrothermally prepared at 30°C (PS1) or 150°C (PS2), was characterized by various methods for better comprehension of the sulfide-nitride topotactic conversion model.  相似文献   
258.
We rigorously justify the infinite Prandtl number model of convection as the limit of the Boussinesq approximation to the Rayleigh‐Bénard convection as the Prandtl number approaches infinity. This is a singular limit problem involving an initial layer. © 2003 Wiley Periodicals, Inc.  相似文献   
259.
The generalized independent set (GIS) problem was first introduced by Hochbaum and Pathria (Forest Sci 43(4), 544–554, 1997) and independently explored in greater detail by Hochbaum (Manage Sci 50(6), 709–123, 2004). This problem, with applications in forest management and a variety of related areas, is a generalization of the classical maximum independent set problem. In this paper we highlight a natural, nonlinear formulation for the problem that is an attractive alternative to the linear model found in the literature. The effectiveness of this alternative formulation is demonstrated by computational experience on test problems of varying size and density, disclosing a dramatic reduction in the time to obtain optimal and near optimal solutions and an ability to solve much larger problems.  相似文献   
260.
Pascal triangles are formulated for computing the coefficients of the B-spline series representation of the compactly supported spline-wavelets with minimum support and their derivatives. It is shown that with the alternating signs removed, all these sequences are totally positive. On the other hand, truncations of the reciprocal Euler-Frobenius polynomials lead to finite sequences for orthogonal wavelet decompositions. For this purpose, sharp estimates are given in terms of the exact reconstruction of these approximate decomposed components. Research supported by NSF Grant DMS 89-0-01345 and ARO Contract No. DAAL 03-90-G-0091.  相似文献   
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