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911.
In this paper we introduce spatial phase coding of incoherent optical signals for representing signed numbers in optical processors and present an experimental demonstration of this coding technique. If a diffraction grating, such as an acousto-optic cell, modulates a stream of light, the image of the grating can be recovered from the diffracted beam. The position of the grating image, or more precisely its phase, can be used to denote the sign of the number represented by the diffracted light. The intensity of the light represents the magnitude of the number. This technique is more economical than current methods in terms of the number of information channels required to represent a number and the amount of post processing required. 相似文献
912.
Shiva Raj Sarala Devi Ch. Seshikala G. Ram Reddy M. G. 《Journal of Chemical Sciences》1992,104(1):15-20
The proton ligand constants of 4-chloro and 4-amino picolinic acid N-oxide and the formation constants of corresponding binary
chelates of Cu(II) and Ni(II) have been measured at 30°C and 0.1M ionic strength in varying percentages of dioxane-water,
acetone-water, ethanol-water and isopropanol-water. The results are discussed with reference to the change in dielectric constants
of water in the presence of organic solvent, change in the structuredness of water, change in hydrogen bonding ability of
the organic solvent in water, solvent basicity and proton solvation by organic solvent. The values have been compared with
aqueous and mixed aqueous systems of picolinic acid N-oxide and 4-methoxy picolinic acid N-oxide. 相似文献
913.
Let G be a graph that admits a perfect matching. The forcing number of a perfect matching M of G is defined as the smallest number of edges in a subset S M, such that S is in no other perfect matching. We show that for the 2n × 2n square grid, the forcing number of any perfect matching is bounded below by n and above by n2. Both bounds are sharp. We also establish a connection between the forcing problem and the minimum feedback set problem. Finally, we present some conjectures about forcing numbers in other graphs. 相似文献
914.
We study four measures of problem instance behavior that might account for the observed differences in interior-point method
(IPM) iterations when these methods are used to solve semidefinite programming (SDP) problem instances: (i) an aggregate geometry
measure related to the primal and dual feasible regions (aspect ratios) and norms of the optimal solutions, (ii) the (Renegar-)
condition measure C(d) of the data instance, (iii) a measure of the near-absence of strict complementarity of the optimal solution, and (iv) the
level of degeneracy of the optimal solution. We compute these measures for the SDPLIB suite problem instances and measure
the sample correlation (CORR) between these measures and IPM iteration counts (solved using the software SDPT3) when these
measures have finite values. Our conclusions are roughly as follows: the aggregate geometry measure is highly correlated with
IPM iterations (CORR = 0.901), and provides a very good explanation of IPM iterations, particularly for problem instances
with solutions of small norm and aspect ratio. The condition measure C(d) is also correlated with IPM iterations, but less so than the aggregate geometry measure (CORR = 0.630). The near-absence
of strict complementarity is weakly correlated with IPM iterations (CORR = 0.423). The level of degeneracy of the optimal
solution is essentially uncorrelated with IPM iterations.
This research has been partially supported through the MIT-Singapore Alliance. 相似文献
915.
The independence polynomial, ω(G,x)=∑wkxk, of a graph, G, has coefficients, wk, that enumerate the ways of selecting k vertices from G so that no two selected vertices share an edge. The independence number of G is the largest value of k for which wk≠0. Little is known of less straightforward relationships between graph structure and the properties of ω(G,x), in part because of the difficulty of calculating values of wk for specific graphs. This study presents a new algorithm for these calculations which is both faster than existing ones and easily adaptable to high-level computer languages. 相似文献
916.
第Ⅱ类三态叠加多模叠加态光场等幂次2m+1次方Y压缩 总被引:2,自引:0,他引:2
构造了由多模虚相干态|{iZj}>q、多模虚相干态的相反态|{-iZj}>q和多模真空态|{Oj}>q这三种不同的量子光场态的线性叠加所组成的第Ⅱ类三态叠加多模叠加态光场|ψ2(3)>q.利用多模压缩态理论,研究了态|ψ2(3)>q的广义非线性等幂次2m+1次方Y压缩特性.结果发现:在压缩次数N=2m+1(m=0,1,2,3,…,…)的条件下,只要各模的初始相位和态间的初始相位差分别满足一定的取值条件,态|ψ2(3)>q就可呈现出周期性变化的、任意奇数次的广义非线性等幂次N次方Y压缩效应. 相似文献
917.
E. Ramos T. Lopez P. Bosch M. Asomoza R. Gomez 《Journal of Sol-Gel Science and Technology》1997,8(1-3):437-442
Sol-Gel Hydrotalcites were synthesized using magnesium ethoxide and variable aluminum sources: aluminum acetilacetonate, aluminum
chloride, aluminum nitrate and aluminum sulfate; in all cases, the gelation was done at pH 10. X-ray diffraction studies show
that the crystallinity depends on the aluminum precursor used. The crystallinity was found in the order aluminum acetylcetonate>aluminum
chloride>aluminum nitrate>aluminum sulfate. The precursor determines the sintering behavior as well. 相似文献
918.
刘蕴贤 《高等学校计算数学学报》2002,24(1):1-10
1 引 言三维热传导型半导体器件瞬态问题的数学模型由四个非线性偏微分方程描述[1 ,2 ] ,记 Ω为 Ω=[0 ,1 ] 3的边界 ,三维问题-Δψ =α( p -e+ N( x) ) , ( x,t)∈Ω× [0 ,T] ,( 1 .1 ) e t= . ( De( x) e-μe( x) e ψ) -R( e,p,T) , ( x,t)∈Ω× ( 0 ,T] ,( 1 .2 ) p t= . ( Dp( x) p +μp( x) p ψ) -R( e,p,T) , ( x,t)∈Ω× ( 0 ,T] ,( 1 .3 )ρ( x) T t-ΔT =[( Dp( x) p +μp( x) p ψ) -( De( x) e-μe( x) e ψ) ] . ψ, ( x,t)∈Ω× ( 0 ,T] . ( 1 .4 )ψ( x,t) =e( x,t) =p( … 相似文献
919.
An asymptotic formula for the number of points of an arbitrary lattice in the hyperbolic cross is obtained.
Translated fromMatematicheskie Zametki, Vol. 63, No. 3, pp. 363–369, March, 1998.
The authors wish to thank Professors N. M. Korobov and V. I. Nechaev for their attention and useful discussions. 相似文献
920.
本文提出了区间值函数单调的概念,并利用所定义的区间值函数刻划了模糊数值函数的H-差,H-可导性和S-可导性及其相互关系. 相似文献