Microscopic models of spin crossover

The basic model for thermal spin crossover (SCO) is discussed in its microscopic and thermodynamic formulation. Compared to the basic model, its more elaborated forms formulated in course of almost 50 years are briefly reviewed with emphasis on their additional features. A separate section is devoted to the newer developments in the field of modelling of the SCO nanoparticles. The presentation of models is led in a comparative way to provide an accessible outline of the foundations of modern theoretical research on SCO and a simple applicability in quantitative interpretation of experiments.     

保守超混沌在数字图像加密中的应用

基于保守超混沌信号，提出一种数字图像加密算法.该算法利用一个5维保守超混沌系统产生5通道时间序列对原图像分别进行RGB三基色像素级和比特级置乱，再对置乱的RGB三基色作异或操作.在此基础上，利用其中一个通道的时间序列作为密钥分别进行一次正向异或操作的扩散和S盒处理，一次反向异或操作的扩散与S盒处理及置乱，得到加密的图像.最后利用直方图、信息熵、密钥空间等安全性指标对该加密算法进行测试，并与一个五维耗散超混沌系统应用于图像加密的实例进行对比.数值结果表明保守混沌应用到数字图像加密的算法具有更高的安全性和可靠性.     

Creation and control of quasi-two dimensional electron gas at yttrium aluminum oxides/strontium titanate heterointerfaces by spin coating

Despite of extensive researches about oxide heterointerfaces, preparing method and intrinsic mechanism are all challenging topics. Here, we generate a series of stable quasi two dimensional electron gases (q-2DEGs) at yttrium aluminum oxides/strontium titanate (YAO/STO) heterointerfaces by the spin coating for the first time. It is found that the thickness and the stoichiometry ratio are the key factors for the creation of q-2DEG, which is formed under the premise of thickness (about 81.1 ∼ 356.4 nm) and the rich-Al (Al:Y≥1:1). The underlying mechanism can be attributed to oxygen vacancies derived from the redox reaction between YAO film and STO substrate. In addition, the conductive behavior can be modulated by the light illumination and the value of photoinduced change reaches 153.7% at low temperature. This work paves a novel way to fabricate 2DEG massively and helpful for a deep understanding about the conductive mechanism of oxide heterostructures.     

Efficient implementation of Radau collocation methods

In this paper we define an efficient implementation of Runge–Kutta methods of Radau IIA type, which are commonly used when solving stiff ODE-IVPs problems. The proposed implementation relies on an alternative low-rank formulation of the methods, for which a splitting procedure is easily defined. The linear convergence analysis of this splitting procedure exhibits excellent properties, which are confirmed by its performance on a few numerical tests.     

Program Fullerene: A software package for constructing and analyzing structures of regular fullerenes

Fullerene (Version 4.4) is a general purpose open‐source program that can generate any fullerene isomer, perform topological and graph theoretical analysis, as well as calculate a number of physical and chemical properties. The program creates symmetric planar drawings of the fullerene graph and generates accurate molecular 3D geometries by way of force‐field optimization, serving as a good starting point for further quantum theoretical treatments. It includes a number of fullerene‐to‐fullerene transformations, such as Goldberg–Coxeter transforms, Stone–Wales transforms, Endo–Kroto, Yoshida–Fowler, and Brinkmann–Fowler vertex insertions. The program is written in standard Fortran and C++ and can easily be installed in a Linux or UNIX environment. © 2013 Wiley Periodicals, Inc.     

Stabilization of solutions of dissipative Hamiltonian systems

We study the stabilization of solutions of damped Hamiltonian systems. We give sufficient conditions for convergence of these solutions, decay estimate and examples of applications.