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951.
952.
Antónia Földes 《Periodica Mathematica Hungarica》2005,50(1-2):117-134
Summary Some topics of our twenty some years of joint work is discussed. Just to name a few; joint behavior of the maximum of the Wiener process and its location, global and local almost sure limit theorems, strong approximation of the planar local time difference, a general Strassen type theorem, maximal local time on subsets. 相似文献
953.
嵌段共聚物溶致液晶相中水的2H-NMR动力学分析 总被引:3,自引:1,他引:2
采用D2O 的2H-NMR线型和弛豫分析了PEO-PPO-PEO/D2O/对二甲苯体系的层状和六角液晶相的动力学行为. 通过实验测得了两个不同体系的自旋 晶格弛豫时间T1、自旋-自旋弛豫时间T2和2H-NMR 谱. 2H-NMR 谱均为具有四极劈裂的粉末谱线型,且在谱图的中心,βLD=54.7°时存在一个倒峰. 倒峰的出现直接表明引起体系中弛豫的主要动力学过程处于极窄化区域. 采用NMR弛豫模型,通过调节动力学参数,使理论模拟的2H-NMR谱、弛豫时间、倒峰的大小与实验的对应量相吻合,求得了体系的动力学参数. 相似文献
954.
Ga‐Young Lee Jin‐Hyang Kim Hyo Jin No Ju‐Yeon Lee Bum Ku Rhee Hee‐dok Choi 《Journal of polymer science. Part A, Polymer chemistry》2009,47(7):1911-1919
1‐{3,4‐Di‐(2‐hydroxyethoxy)phenyl}‐2‐(2‐thiophenyl)ethene (5) was prepared and condensed with terephthaloyl chloride to yield polyester (6). Polymer 6 was reacted with tetracyanoethylene to give a new Y‐type polyester (7) containing 1‐(3,4‐dioxyethoxy)phenyl‐2‐{5‐(2,2,3‐tricyanovinyl)‐2‐thiophenyl)}ethenyl groups as NLO‐chromophores, which are components of the polymer backbones. Polyester 7 is soluble in common organic solvents such as N,N‐dimethylformamide and acetone. Polymer 7 showed a thermal stability up to 300 °C in thermogravimetric analysis with glass transition temperature (Tg) obtained from differential scanning calorimetry near 126 °C. The second harmonic generation (SHG) coefficient (d33) of poled polymer film at the 1560 nm fundamental wavelength was around 6.57 × 10?9 esu. The dipole alignment exhibited high thermal stability up to the Tg, and there was no SHG decay below 125 °C due to the partial main‐chain character of polymer structure, which is acceptable for NLO device applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1911–1919, 2009 相似文献
955.
956.
This paper considers numerical simulation of time‐dependent non‐linear partial differential equation resulting from a single non‐linear conservation law in h, p, k mathematical and computational framework in which k=(k1, k2) are the orders of the approximation spaces in space and time yielding global differentiability of orders (k1?1) and (k2?1) in space and time (hence k‐version of finite element method) using space–time marching process. Time‐dependent viscous Burgers equation is used as a specific model problem that has physical mechanism for viscous dissipation and its theoretical solutions are analytic. The inviscid form, on the other hand, assumes zero viscosity and as a consequence its solutions are non‐analytic as well as non‐unique (Russ. Math. Surv. 1962; 17 (3):145–146; Russ. Math. Surv. 1960; 15 (6):53–111). In references (Russ. Math. Surv. 1962; 17 (3):145–146; Russ. Math. Surv. 1960; 15 (6):53–111) authors demonstrated that the solutions of inviscid Burgers equations can only be approached within a limiting process in which viscosity approaches zero. Many approaches based on artificial viscosity have been published to accomplish this including more recent work on H(Div) least‐squares approach (Commun. Pure Appl. Math. 1965; 18 :697–715) in which artificial viscosity is a function of spatial discretization, which diminishes with progressively refined discretizations. The thrust of the present work is to point out that: (1) viscous form of the Burgers equation already has the essential mechanism of viscosity (which is physical), (2) with progressively increasing Reynolds (Re) number (thereby progressively reduced viscosity) the solutions approach that of the inviscid form, (3) it is possible to compute numerical solutions for any Re number (finite) within hpk framework and space–time least‐squares processes, (4) the space–time residual functional converges monotonically and that it is possible to achieve the desired accuracy, (5) space–time, time marching processes utilizing a single space–time strip are computationally efficient. It is shown that viscous form of the Burgers equation without linearizing provides a physical and viablemechanism for approaching the solutions of inviscid form with progressively increasing Re. Numerical studies are presented and the computed solutions are compared with published work. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
957.
基于分时原理的多相流体比例分配方法 总被引:1,自引:0,他引:1
提出了从“时间”上对多相流进行分配的新思路,分析了分时分配的基本原理,并设计了具体的实现方式。在空气-水实验回路上对分时分配装置进行了实验研究和验证。分时分配的基本原理就是通过“分时”的方法,使整个分配器“空间”内的多相流都能按照给定的时间份额周期性地交替流向对应的支路,从而保证各支路内的多相流具有高度一致的相含量和确定的流量比例。实验研究证明,分时分配法具有切实的可行性,分流比等于分时比且与流量和流体的物性无关,仅取决于分配器的几何参数。 相似文献
958.
Thomas Lorenz 《Set-Valued Analysis》2008,16(1):1-50
The mutational equations of Aubin extend ordinary differential equations to metric spaces (with compact balls). In first-order
geometric evolutions, however, the topological boundary need not be continuous in the sense of Painlevé–Kuratowski. So this
paper suggests a generalization of Aubin’s mutational equations that extends classical notions of dynamical systems and functional
analysis beyond the traditional border of vector spaces: Distribution-like solutions are introduced in a set just supplied
with a countable family of (possibly non-symmetric) distance functions. Moreover their existence is proved by means of Euler
approximations and a form of “weak” sequential compactness (although no continuous linear forms are available beyond topological
vector spaces). This general framework is applied to a first-order geometric example, i.e. compact subsets of ℝ
N
evolving according to the nonlocal properties of both the current set and its proximal normal cones. Here neither regularity
assumptions about the boundaries nor the inclusion principle are required. In particular, we specify sufficient conditions
for the uniqueness of these solutions.
相似文献
959.
HONG Xiaobin LIN Jintong 《Chinese Journal of Lasers》1999,8(2):97-102
1IntroductionInordertometthehighbandwidthrequirementinopticaltimedivisionmultiplex(OTDM)telecommunicationsystems,thesignalmu... 相似文献
960.
利用向量Lyapunov函数,研究了初始时刻变化的微分方程的有界性问题,并得到了相应的结果. 相似文献