Self-aggregation of surfactants in water solution by NMR

Dynamic behavior of surfactant molecules, sodium dodecyl sulfonate (SDSN), cetyl trimethyl ammonium bromide (CTAB) and triton X-100, and their micelles in water solution at various concentrations were studied by chemical shift, self diffusion coefficient (D) and nuclear magnetic resonance relaxation (T₁ and T₂) measurements. Experimental results show that there exist turning points at surfactant concentration (C) nearby the critical micelle concentration (cmc) for all of the above-mentioned parameters, which approach the constant values when C equals 5 to 10 times cmc. T₁ and T₂ measurements show that when C<cmc, Triton X-100 molecules exhibit fast isotropic motion in water solution. After micellization, the motion of hydrophobic chains is far away from the extreme narrowing condition, however, the long hydrophilic oxyethylene chains move relatively freely, although their T₁ and T₂ become shorter in comparison with those of the molecules in mono-molecular state. The behavior of the hydrophobic chains within the micellar core of SDSN and CTAB is similar to that of Triton X-100 to some extent. Project supported by the National Climbing Project.     

Recovering a Family of Two-Dimensional Gaussian Variables from the Minimum Process

Suppose that {(X _t, Y _t): t>}0 is a family of two independent Gaussian random variables with means m ₁(t) and m ₂(t) and variances σ ² ₁(t) and σ ² ₂(t). If at every time t>0 the first and second moment of the minimum process X _t∧Y _t are known, are the parameters governing these four moment functions uniquely determined ? We answer this question in the negative for a large class of Gaussian families including the “Brownian” case. Except for some degenerate situation where one variance function dominates the other, in which case the recovery of the parameters is fully successful, the second moment of the minimum process does not provide any additional clues on identifying the parameters.     

Some relationships for the double modified generalized analytic function space Fourier–Feynman transform and its applications

In this paper we first introduce the concept of a double modified analytic function space Fourier–Feynman transform using the double modified analytic function space integral. We then proceed to establish the existence of the modified analytic function space Fourier–Feynman transform for all functionals in the Banach algebra. Finally we use this double modified analytic function space transform to explain various physical phenomenon.     

期权定价理论中的物理学

布朗运动理论是布莱克－舒尔斯期权定价理论的基础，这意味着现代金融工程需要物理学。现代金融学向定量科学发展是历史的必然，物理学进入金融业也是势在必行，但是，金融工程是一项大的综合性工程，物理模型只是它的一，且要走的路还很长，还有许多工作需要物理学家去做，特别是要用新的物理思想，构造出新的、实用的模型。     

Dynamics of arrays of legs powered by a discrete electrical model of nerve

This paper studies the dynamics of an array of legs connected through magnetic coupling at nodes of a discrete electrical model of nerve fibre or a linear electric line. Considering legs fixed on spring, it is found that they exhibit pulse like behavior when the electrical signal propagates in the array. The amplitude of the pulse like motion increases with the magnitude of magnetic field. Legs without spring undergo a step motion at the passage of the electrical signal, advancing in a given distance before they stop. The magnitude of the step also increases with the magnetic coupling. Considering a linear electrical line excited at a single node, it is found that the legs oscillate with decreasing amplitude till the center of the line and increasing amplitude from the center to the first node of the linear line.     

On the path regularity of a stochastic process in a hilbert space,defined by the ito integral

Poisson Processes, by J.F.C. Kingman. Clarendon Press (Oxford University Press), Oxford (1993), 104 pp. $ 39,95 ISBN 0-19-853693-3     

Spread of branching diffusion: Sharp asymptotics

A one-dimensional branching diffusion with a stable drift is considered. Let R_t denote the position of the rightmost particle at time t. It is shown that R_t , properly normalized, has a limiting distribution.     

带Brown运动的随机奇异积分的存在性

在轨迹二阶导数具有Hlder连续的条件下,利用高阶奇异积分思想和概率极限的理论,研究了在Brown运动下的随机奇异积分.得到了以Brown运动为积分元的随机奇异积分是存在性定理.     

Conserved dynamics and interface roughening in spontaneous imbibition: A critical overview

Imbibition phenomena have been widely used experimentally and theoretically to study the kinetic roughening of interfaces. We critically discuss the existing experiments and some associated theoretical approaches on the scaling properties of the imbibition front, with particular attention to the conservation law associated to the fluid, to problems arising from the actual structure of the embedding medium, and to external influences such as evaporation and gravity. Our main conclusion is that the scaling of moving interfaces includes many crossover phenomena, with competition between the average capillary pressure gradient and its fluctuations setting the maximal lengthscale for roughening. We discuss the physics of both pinned and moving interfaces and the ability of the existing models to account for their properties. Received 17 February 1999 and Received in final form 24 November 1999