具有速度正反饋的变带宽伺服系统分析及其数字仿真

本文分析了速度正反馈变带宽伺服系统特点,它在精度及快速性方面接近于再生反馈系统,但结构简单、工作可靠、调整维护方便。通过线性仿真,定量分析了系统动态指标,验证了理论设计参数合理性。通过非线性仿真,定量分析了理论分析比较困难的动态响应问题,得到了一些有益的结论。     

Positive Psychology at the Summit.

Psychology has traditionally placed more emphasis on the negative than positive aspects of human behavior. The positive psychology movement, since its beginnings in 1999, has made major advances toward correcting this imbalance. Research inspired by the movement now spans an impressive range of topics, including many that are absolutely essential to a comprehensive psychological understanding of human nature. The present special issue provides a sampling of some of the best work in the area. All but the first and last articles come from presentations at the Second International Positive Psychology Summit, held in 2003 in Washington, DC. This sample can be supplemented by the chapters that have appeared in several recent anthologies of contemporary research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Necessary conditions for positive realizability of continuous-time linear systems

This paper deals with the positive realization problem. The problem is to find, from a given transfer function, a state equation in which state variables and the output take nonnegative values whenever initial states and inputs are nonnegative. Necessary conditions are investigated and a new one is given, together with some related results.     

数学建模思想融入微积分课程中的两个教学插件

本文讨论了可融入微积分课程教学中的两个数学模型插件。第一个是研究市场调节下平衡价格的阻尼振荡模型，使用了二阶线性常系数微分方程的课程知识；第二个是在引进社会福利因素时商品的最优定价模型，使用了定积分和微分法的课程知识。在模型建立过程中，强调了建模假设的修改与完善技巧。     

Stability robustness for linear state space models - a Lyapunov mapping approach

Some Pythagorean-like conditions for the existence of a common Lyapunov solution for two given matrices are presented. These conditions are set on the Lyapunov mappings associated with given matrices. The key is the semipositiveness of linear mappings defined on symmetric matrices. From the viewpoint of the existence of a common Lyapunov solution, some known stability robustness results are reviewed and refined.     

Influence of structural parameters on proton insertion in γ-MnO2

The proton insertion/deinsertion behavior of γ-MnO₂ samples of various oxygen contents and various structural parameters has been studied. The analysis of the voltammograms observed during the discharges and charges of the different samples is presented, and leads to a classification of the samples according to their structural parameters. The proton insertion capacities and the cycling properties of the different samples have been compared and correlated to their structural properties.     

Input-output stability of systems with backlash

The objective of this work is to study the stability of systems with backlash, from an input-output point of view. In the first part, an L_∞ analysis is addressed. This analysis provides not only conditions for boundedness of the loop signals, but also results on existence of solutions, based on Schauder fixed point theorem. In the second part, the system is studied using an L₂ or conic sector approach. The backlash graph is confined into certain conic sector, which is shown to be optimum or maximal. The conic inequality induces frequencial conditions on the linear part, which are further relaxed introducing dynamic multipliers. In the third part, both L_∞ and L₂ techniques are combined reaching a final criterion which results in a Popov-like stability condition.     

Methodological issues in P technique.

The P technique is a multiple time series in which observations are taken in a definite time series and usually consists of measures which are not independent. This lack of independence creates statistical problems which are examined. Much work is needed on the fundamental theory of analysis of multiple time series. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

转基因作物筛查用阳性质粒分子的构建及应用研究

通过分析全球商业化种植的转基因作物分子特征,选取常用的调控元件启动子CaMV35S、FMV35S和nos,终止子NOS、T-35S、g73′和E93′,标记基因bar、NPTII、hptII、pmi作为筛查靶标序列,通过重组PCR技术将这些元件克隆到双元载体pBI121上,构建成包含11个转基因元件的通用阳性质粒分子pBI121-ELEMENTS。质粒序列信息已提交至GenBank并获得序列号HM047294。该质粒分子对目前国内外批准的5类主要转基因作物（大豆、油菜、玉米、棉花和水稻）理论筛查覆盖率达到91.5%,对我国批准进口的27种转基因作物的理论筛查覆盖率达100%。以pBI121-ELEMENTS为阳性对照,筛查7个转基因品系,结果显示该分子能够有效用于转基因作物定性筛查。