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81.
聚合公理系统的布尔值模型 总被引:3,自引:1,他引:2
本文以ZFc聚合公理系统为基础,构造了ZFc的布尔值模型,证明了关键定理9、定理15,使得ZF集合公理系统的布尔值模型VOn^(B)是聚合公理系统的布尔值模型〔VON^(B)〕的子模型,并且ZF集合公理组在〔VON^(B)〕中满足。 相似文献
82.
The Jamin shearing interferometer is very useful in wavefront testing, especially for the low coherent light. Based on this interferometer, a polarization phase-shifting Jamin shearing interferometer is proposed to improve the performance. In the interferometer, two interference beams are linearly polarized and a polarization phase shifter is applied to realize the phase shifting. Different types of configurations of the interferometer are given. With phase-shifting interferograms, the precision of the interferometer can be improved. The interferometer is kept as an equal optical path system and its shearing amount remains changeable with simple structure and easy operation. In experiments, phase-shifting interferograms are obtained by rotating the analyzer. The usefulness of the interferometer is verified. 相似文献
83.
84.
We study three types of practical optimization problems faced by a firm that can control its liquid reserves by paying dividends
and by issuing new equity. In the first problem, we consider the classical dividend problem without equity issuance. The second
problem aims at maximizing the expected discounted dividend payments minus the expected discounted costs of issuing new equity
over strategies associated with positive reserves at all times. The third problem has the same objective as the second one,
but with no constraints on the reserves. Under the assumption of proportional transaction costs, we identify the value functions
and the optimal strategies. We also present the relationship between three problems. 相似文献
85.
In this paper we establish Chung’s law of the iterated logarithm for a class of anisotropic Gaussian random fields with stationary increments. This result is applicable to space–time Gaussian random fields and solution to the stochastic fractional heat equation. 相似文献
86.
Nguyen Ngoc Luan 《Applicable analysis》2013,92(9):1694-1704
This paper establishes several new facts on generalized polyhedral convex sets and shows how they can be used in vector optimization. Among other things, a scalarization formula for the efficient solution sets of generalized linear vector optimization problems is obtained. We also prove that the efficient solution set of a generalized linear vector optimization problem in a locally convex Hausdorff topological vector space is the union of finitely many generalized polyhedral convex sets and it is connected by line segments. 相似文献
87.
88.
Xingyuan Wang Dapeng Luan 《Communications in Nonlinear Science & Numerical Simulation》2013,18(11):3075-3085
In this paper, a novel image encryption scheme is proposed based on reversible cellular automata (RCA) combining chaos. In this algorithm, an intertwining logistic map with complex behavior and periodic boundary reversible cellular automata are used. We split each pixel of image into units of 4 bits, then adopt pseudorandom key stream generated by the intertwining logistic map to permute these units in confusion stage. And in diffusion stage, two-dimensional reversible cellular automata which are discrete dynamical systems are applied to iterate many rounds to achieve diffusion on bit-level, in which we only consider the higher 4 bits in a pixel because the higher 4 bits carry almost the information of an image. Theoretical analysis and experimental results demonstrate the proposed algorithm achieves a high security level and processes good performance against common attacks like differential attack and statistical attack. This algorithm belongs to the class of symmetric systems. 相似文献
89.
Using full-potential linearized augmented plane wave (FLAPW) method, we investigated the effects of intrinsic vacancies on electronic and magnetic properties in graphene-like ZnO nanosheets. The results show that the oxygen vacancy (VO) has no influence on magnetism in ZnO nanosheet, whereas the Zn vacancy (VZn) lead to spin polarization of the nanostructures with a total magnetic moment of 2.0μB due to O-2p and Zn-3d hybridization. When the distance of two VZn defects increases to 6.499 Å, the system shows an intriguing half-metallic character with 100% spin-polarized carriers due to O(2p)–Zn(3d)–O(2p) coupling chain between two VZn defects. 相似文献
90.
A novel broadband transmission method to determine polymer film thickness during manufacturing is proposed, and a measurement system is developed based on this method. The relationship between broadband optical power and film thickness is deduced according to the Lambert-Beer law. The system is composed of a halogen light and an optical power meter. Results show that the measurement error of this method is approximately 1 μm, and the resolution of the system is below 0.4 μm for polymer films with less than 100-μm thickness. 相似文献