Charge transport in a polypeptide chain

Charge transport is one important example of signal transduction in a protein which is responsible for action at a distance, and is a fundamental process in biochemical action. A model is presented in which electronic effects interact with motional processes to combine into a bifunctional model. This model is investigated with new detailed molecular dynamics calculations and successfully explains such action at a distance. Received 1st February 2002 / Received in final form 26 May 2002 Published online 13 September 2002     

Spray Freeze-drying – The Process of Choice for Low Water Soluble Drugs?

Most of the novel highly potent drugs, developed on the basis of modern molecular medicine, taking into account cell surface recognition techniques, show poor water solubility. A chemical modification of the drug substance enhancing the solubility often decreases the pharmacological activity. Thus, as an alternative an increase of the solubility can be obtained by the reduction of the size of the drug particles. Unfortunately, it is often difficult to obtain micro or nanosized drug particles by classical or more advanced crystallization using supercritical gases or by milling techniques. In addition, nanosized particles are often not physically stable and need to be stabilized in an appropriate matrix. Thus, it may be of interest to manufacture directly nanosized drug particles stabilized in an inert hydrophilic matrix, i.e. nanostructured and nanocomposite systems. Solid solutions and solid dispersions represent nanostructured and nanocomposite systems. In this context, the use of the vacuum-fluidized-bed technique for the spray-drying of a low water soluble drug cosolubilized with a hydrophilic excipient in a polar organic solvent is discussed. In order to avoid the use of organic solvents, a special spray-freeze-drying technique working at atmospheric pressure is presented. This process is very suitable for temperature and otherwise sensitive drugs such as pharmaproteins.     

Theory of high temperature superconductivity in YBa2Cu3O7_δ

A theory of high temperature superconductivity in YBa₂Cu₃O₇__δ compound has been developed on the basis of the momentum pairing of electrons through the relativistic Darwin interaction. The transport behaviour of electrons is explained in terms of a mechanism of correlated electron transfer arising from the electron-phonon coupling. A model Hamiltonian has been developed to describe the superconducting properties of the system. This gives an energy gap which is higher than the BCS value. Attempts have been made to explain the absence of isotope effect, the linear dependence of specific heat, the presence of larger temperature-independent paramagnetism in the normal phase and the softening of some of the optic phonon modes observed in this system.     

A search technique for global optimization in a chaotic environment

We describe a new algorithm which uses the trajectories of a discrete dynamical system to sample the domain of an unconstrained objective function in search of global minima. The algorithm is unusually adept at avoiding nonoptimal local minima and successfully converging to a global minimum. Trajectories generated by the algorithm for objective functions with many local minima exhibit chaotic behavior, in the sense that they are extremely sensitive to changes in initial conditions and system parameters. In this context, chaos seems to have a beneficial effect: failure to converge to a global minimum from a given initial point can often be rectified by making arbitrarily small changes in the system parameters.     

Inequalities for the Moments and Distribution of the Ladder Height of a Random Walk

We obtain upper bounds for the tail distribution of the first nonnegative sum of a random walk and for the moments of the overshoot over an arbitrary nonnegative level if the expectation of jumps is positive and close to zero. In addition, we find an estimate for the expectation of the first ladder epoch.     

Nielsen realization for 3-manifolds containing two-sided projective planes

For compact irreducible sufficiently large 3-manifolds containing 2-sided projective planes, we consider the following Realization Problem: Given a finite subgroup of the outer automorphism group of the fundamental group, is there a finite group of homeomorphisms, which induces this subgroup? Received: 16 November 1999; in final form: 18 January 2001 / Published online: 8 November 2002     

Banach空间中强增生型变分包含解的具误差的Ishikawa迭代逼近

该文研究Ｂａｎａｃｈ空间中一类强增生型变分包含解的存在性及其具误差的Ｉｓｈｉｋａｗａ迭代程序的收敛性问题．该文结果是几位作者早期与最近的相应结果的改进和推广．     

GAUSSIAN WHITE NOISE CALCULUS OF GENERALIZED EXPANSION

A new framework of Gaussian white noise calculus is established, in line with generalized expansion in [3, 4, 7]. A suitable frame of Fock expansion is presented on Gaussian generalized expansion functionals being introduced here, which provides the integral kernel operator decomposition of the second quantization of Koopman operators for chaotic dynamical systems, in terms of annihilation operators dt and its dual, creation operators t*.     

电子束产生大尺度等离子体过程的数值模拟研究

建立了一个四组分一维混合模型，对电子束注入大气产生大尺度等离子体的过程进行了数值模拟.结果表明了能量为140keV、流强为50mA/cm²的注入电子束，可以产生线度为0.5m，密度为10¹²cm^-3量级的大气环境下等离子体.电子束所伴随的空间电荷效应由于等离子体的产生会很快消失，不影响后续的等离子体产生过程.电子束注入流强主要影响产生等离子体的密度，而电子束能量则同时影响其空间线度和密度. 关键词： 电子束 碰撞 电离     

Ⅴ型三能级原子与双模奇偶纠缠相干光场相互作用系统的光子统计性质

本文采用求解Schroedinger方程和数值计算方法，研究了Ⅴ-型三能级原子与双模奇偶纠缠相干光场相互作用系统的光子统计性质，结果表明：此性质与双模奇偶纠缠相干光场的纠缠程度、失谐量、原子的初态以及双模光的平均光子数相关联．