Quantum HeisenbergS=1/2 spin glass with ferromagnetic coupling and random Dzyaloshinskii-Moriya interactions

By means of the generalized static replica symmetric spin glass theory, a quantum HeisenbergS=1/2 spin glass model with the infinite-ranged random Dzyaloshinskii-Moriya (DM) interaction and ferromagnetic coupling is investigated. The dependence of entropy, specific heat, susceptibility and the corresponding order parameters on temperature is studied numerically for different ferromagnetic interactions and fixed anisotropy. Two spin glass phases has been found including transverse and mixed spin glass phases. It has been shown that the local susceptibility exhibits double-cusp features for different ferromagnetic coupling (J ₀). Phase transition poins are found in the specific heat-temperature plane at various ferromagnetic coupling values. Additionally, the dependence of the spontaneous moment on temperature is calculated.     

背景噪声限下直接检测光PPM编码系统的性能研究

本文研究了背景噪声限下采用编码的直接检测光ＰＰＭ系统的性能，分析了具有不同码率的采用硬判决译码的ＲＳ码，采用最大似然（ＭＬ）译码的卷积码的性能及未编码的ＰＰＭ系统的性能，给出了相应的误比特率和每信息比特信噪比的关系曲线。结果表明：对背景噪声限下的直接检测光ＰＰＭ系统，随着码率的降低，编码不一定能改善系统性能。     

Phase Transition VO2 Thin Films for Optical Switches

This paper presents a method to make vanadium dioxide (VO₂) crystallites on silicon substrates by reactive ion beam sputtering. The thickness of the thin film is about 100nm. The phase transition temperature of VO₂ is 65°C. The transmittance of the semiconducting phase VO₂ is about 50% and it is reduced to as low as 3% in metal phase at the infrared wavelenghth spectrum. The extinction ratio of the optical switches is 12dB. and the insertion loss is of 1-2dB. The switching time is about 1ms.     

灰色Verhulst模型的样条插值函数的残差修正

本用样条函数对灰色Verhulst模型的残差序列进行插值拟合，然后作用于二阶线性微分方程，并以此修正原模型，得到一种新的预测模型的数值解，提高了拟合的精确度。     

日本菊花螺Siphonaria Japonia化学成分的研究(I)

近年来相继从菊花螺属(Siphonaria)海洋软体动物中分离出一系列聚丙酸酯(Polypropi-onate)类化合物.这类化合物在自然界罕见,被认为是菊花螺属软体动物的典型代谢产物.本文实验所用的菊花螺采自福建省湄洲湾莲城半岛.该动物味很苦,有清凉解毒之功.     

三维PDP放电过程数值模拟软件

介绍了三维PDP放电过程模拟软件，该软件可较真实地反映放电单元的实际情况，对放电性能进行优化设计，且具有通用性强、界面友好、使用方便、功能完善等特点。可对不同结构、不同气体成份、不同驱动电压及波形等情况进行计算。     

基于概念网络的文本信息监控技术

由于网上信息的迅速增长,文本信息监控已经成为网上信息管理中的热点研究课题。本文在模糊集和语义网络的理论基础上,构建了模糊值动态约束性概念网络,介绍了该概念网络的基本构建方法,并提出了基于概念网络的文本分析算法。     

Damage and fracture evaluation of granular composite materials by digital image correlation method

This paper presents the applications of digital image correlation technique to the mesoscopic damage and fracture study of some granular based composite materials including steelfiber reinforced concrete, sandstone and crystal-polymer composite. The deformation fields of the composite materials resulted from stress localization were obtained by the correlation computation of the surface images with loading steps and thus the related damage prediction and fracture parameters were evaluated. The correlation searching could be performed either directly based on the gray levels of the digital images or from the wavelet transform (WT) coefficients of the transform spectrum. The latter was developed by the authors and showed higher resolution and sensitivity to the singularity detection. Because the displacement components came from the rough surfaces of the composite materials without any coats of gratings or fringes of optical interferometry, both surface profiles and the deformation fields of the composites were visualized which was helpful to compare each other to analyze the damage of those heterogeneous materials. The project supported by the National Natural Science Foundation of China (10125211 and 10072002), the Scientific Committee of Yunnan Province for the Program of Steel Fiber Reinforced Concrete, and the Institute of Chemical Materials, CAEP at Mianyang     

机载雷达空时二维信号处理自适应权值训练的距离分段递推算法

本文针对机载预警雷达的杂波环境，分析了杂波数据的非平稳性，由此提出在距离上分段实现空时二维自适应处理（STAP）的方法，并通过分析杂波于空间的距离来确定分段的方法。在同时考虑实时性和处理器性能的前提下，给出了一种自适应权值计算的递推算法。理论分析和计算机仿真结果均表明，本文提出的分段递推算法是有效的。     

Isolation and Structure Elucidation of Nortriterpenoids from Schisandra rubriflora

Seven new highly oxygenated nortriterpenoids, rubriflorins D–J ( 1 – 7 ), were isolated from the leaves and stems of Schisandra rubriflora, and their structures were elucidated on the basis of extensive analysis of spectroscopic data. These new compounds feature the opening of ring A compared with related known nortriterpenoids isolated from the genus Schisandra and showed weak activity against HIV‐1.