一种有机锡化合物的合成、晶体结构、抗肿瘤及荧光性能

通过异烟肼和4-N,N-二羟乙基苯甲醛来合成一种席夫碱及其锡配合物,并通过核磁、元素分析以及X-射线单晶衍射来进行结构表征。该平面构型的席夫碱采取二齿配位模式,其中的-C=N-在配位后由反式变为顺式。晶体结构数据以及荧光光谱中的显著红移现象表明锡配合物中的π-共轭体系通过配位反应得以延展。体外细胞毒性数据表明,席夫碱配体及其锡配合物对于A-549,MCF-7和Hela等肿瘤细胞的生长抑制活性要强于顺铂。还通过紫外可见光谱及荧光光谱初步研究了两种化合物与DNA的相互作用,结果表明锡配合物可能通过共价结合来导致DNA双螺旋链变形,而席夫碱分子中的氢键效应及其长平面结构可能会阻碍其嵌入DNA双螺旋链。     

Entropy Production along Dominant Pathway of Nonequilibrium Phase Transition in Mesoscopic Chemical System

We consider a bistable mesoscopic chemical reaction system and calculate entropy produc- tion along the dominant pathway during nonequilibrium phase transition. Using probability generating function method and eikonal approximation, we first convert the chemical master equation into the classical Hamilton-Jacobi equation, and then find the dominant pathways between two steady states in the phase space by calculating zero-energy trajectories. We find that entropy productions are related to the actions of the forward and backward dominant pathways. At the coexistence point where the stabilities of the two steady states are equiv alent, both the system entropy change and the medium entropy change are zero; whereas at non-coexistence point both of them are nonzero.     

Synthesis, photophysical properties and TD-DFT calculation of four two-photon absorbing triphenylamine derivatives

In this study,linear absorption,single-photon excited fluorescence,fluorescence quantum yields,fluorescence lifetime and two-photon excited fluorescence of a series of triphenylamine derivatives (L1,L2,L3 and L4) have been measured.L1 and L3 are D--A type dyes,while L2 and L4 are D--D--A type dyes (D=donor,A=acceptor).The investigated compounds consist of triphenylamine-bearing donor-substituted and/or systematically extended-conjugated length,which are designed to gain insight into the effect of the ethoxyl unit and-linkage length on the linear and nonlinear optical properties.The influence of solvent polarity on the photophysical properties was investigated.Employing time-dependent density functional theory (TD-DFT) calculations,the structure-property relationships are discussed.     

Generalized tripartite scheme for sharing arbitrary 2n-qudit state

Utilizing three non-maximally entangled qutrit pairs as quantum channels, we first propose a generalized tripartite scheme for sharing an arbitrary two-qutrit state with generalized Bell-state measurements. In the scheme if and only if the two recipients collaborate together, they can recover the split qutrit state with the probability determined uniquely by the smallest coefficients of the non-maximally entangled pairs. Afterwards, we further extend the scheme for sharing an arbitrary 2n-qudit state by taking 3n non-maximally entangled qudit pairs as quantum channels. Moreover, the scheme success probability relative to the inherent entanglement in quantum channels and its structure is simply discussed.     

Wigner Functions for the Bateman System on Noncommutative Phase Space

We study an important dissipation system, i.e. the Bateman model on noncommutative phase space. Using the method of deformation quantization, we calculate the Exp functions, and then derive the Wigner functions and the corresponding energy spectra.     

Decomposition methods for time‐domain Maxwell's equations

Decomposition methods based on split operators are proposed for numerical integration of the time‐domain Maxwell's equations for the first time. The methods are obtained by splitting the Hamiltonian function of Maxwell's equations into two analytically computable exponential sub‐propagators in the time direction based on different order decomposition methods, and then the equations are evaluated in the spatial direction by the staggered fourth‐order finite‐difference approximations. The stability and numerical dispersion analysis for different order decomposition methods are also presented. The theoretical predictions are confirmed by our numerical results. Copyright © 2007 John Wiley & Sons, Ltd.     

Large Deviations for Some Dependent Sequences

Let （Xi） be a martingale difference sequence and Sn=∑^ni=1Xi Suppose （Xi） i=1 is bounded in L^p. In the case p ≥2, Lesigne and Volny （Stochastic Process. Appl. 96 （2001） 143） obtained the estimation μ（Sn 〉 n） ≤ cn^-p/2, Yulin Li （Statist. Probab. Lett. 62 （2003） 317） generalized the result to the case when p ∈ （1,2] and obtained μ（Sn 〉 n） ≤ cn^l-p, these are optimal in a certain sense. In this article, the authors study the large deviation of Sn for some dependent sequences and obtain the same order optimal upper bounds for μ（Sn 〉 n） as those for martingale difference sequence.     

退化时滞微分系统的特征根分布与指数稳定

该文首先研究了退化时滞微分系统的特征根分布, 指出如果退化时滞微分系统的所有特征根都具有负实部, 在一个条件下, 特征根的负实部的最大值为负.由此可以得到一个条件, 在该条件下如果所有特征根都具有负实部, 则退化时滞微分系统的解是指数稳定的.作为例子, 对中立型给出其解为指数稳定的条件.     

一类双调和方程的可解性

利用上下解方法、嵌入定理和Leray-schauder不动点定理证明了一类双调和方程弱解的存在性定理.做为定理的应用,给出了一个实例.