自由基稳定性的新观点

许多《有机化学》教科书一致认为烷基的相对稳定性次序是：叔基＞仲基＞伯基＞甲基，事实上这种次序犯有严重的逻辑错误，通过举例说明了错误所在，并介绍了一种新的自由基相对稳定性次序定量化标准－－稳定化能（SE）的计算方法，叔基、仲基、伯基、甲基的SE值分别为16.73、4.35、7.28、0kJ/mol。利用求得的SE值估算了20种烃类的健离解能（BDE）。结果表明，计算值与文献报道值吻合良好，有75％的BDE值计算结果与文献报道值的相对误差小于3.00%，有90％的BDE值计算结果与文献报道值的相对误差小于8.3%。     

A robust tolerance design method based on process capability

INTRODUCTIONTolerancedesignisabridgetolinktherequirementofproductperformanceandthemanufacturingprocess;andaffectsnotonlytheproductperformance,butalsothecostoftheproductandthemanufacturingprocess.There foreComputerAidedTolerancing (CAT)be comesthekeytechniqueforintegratingCAD CAPP CAM (WuandYang,1999) .Tradition ally,thetoleranceisassignedtothecomponentdimensionsaccordingtotheminimumcost.Therestrictionofthemanufacturingabilityoftoolsthatthefactoryownsisneglected (Jietal.,1999) .Asa…     

Robust exponential stability analysis of a larger class of discrete-time recurrent neural networks

The robust exponential stability of a larger class of discrete-time recurrent neural networks (RNNs) is explored in this paper. A novel neural network model, named standard neural network model (SNNM), is introduced to provide a general framework for stability analysis of RNNs. Most of the existing RNNs can be transformed into SNNMs to be analyzed in a unified way. Applying Lyapunov stability theory method and S-Procedure technique, two useful criteria of robust exponential stability for the discrete-time SNNMs are derived. The conditions presented are formulated as linear matrix inequalities (LMIs) to be easily solved using existing efficient convex optimization techniques. An example is presented to demonstrate the transformation procedure and the effectiveness of the results.     

大学生安全防范体系的构建

构建大学生安全防范体系,要突出一个“早”字,抓好新生入学安全教育,并贯穿于整个大学生活;抓好一个“章”字,建立健全各种规章制度;完善一个“网”字,构建强大的校园安全保卫网络;体现一个“实”字,认真扎实,从点滴做起;掌握一个“严”字,坚持原则,不徇私情。     

Mixed G<Emphasis Type="Italic">l</Emphasis><Subscript>2</Subscript>/G<Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript> multi-channel multi-objective control synthesis for discrete time systems

This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalizedl ₂ (Gl ₂) and generalizedH ₂ (GH ₂) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis variables. Consequently, the multi-channel multi-objective mixed Gl ₂/GH ₂ control problem can be solved less conservatively using computationally tractable algorithms developed in the paper. Project supported by the National Natural Science Foundation of China (No. 60374028), and the Scientific Research Foundation for Returned Overseas Chinese Scholars, Ministry of Education (No. [2004]176)     

单宁对杨梅汁花色苷稳定性的影响

分析了单宁对增加杨梅汁花色苷稳定性的效果。在pH=4.5和pH=3.2时加入单宁使杨梅汁最大吸收波长和最大吸光度增大。在pH为1.0时单宁浓度增大导致杨梅汁最大吸收波长增大，但最大吸光度没有增加。单宁和杨梅汁花色苷的辅助色素反应为放热反应，其△H等于-8.481kJ/mol, △S为7.286J/mol。温度的升高促进辅助色素反应向分解方向进行。     

空调系统的水处理

简明地描述了空调水处理的必要性,冷却水的特点和水处理的具体方法.对膦酸盐和聚丙烯复合药剂的处理效果作了介绍.推荐了以电导为指标的水质控制方式和旁滤池安装的方式.     

具有时变不确定参数的线性时滞系统的鲁棒镇定

研究了具有时变不确定参数的线性时滞系统的鲁棒镇定问题．提出鲁棒稳定化控制器一种新的设计方法．现有的一些结果可以作为本文的一些特例得到．     

明代泰宁卫地域的变迁

明代泰宁卫部落经历了由盛至衰的过程,地域也因此发生了一系列变化。该部落自永乐再封开始,向往中原,以战或贡的方式渐次南下,大规模南下是在宣德时期。正统年间,其中心地域基本稳定在明边境。后期,泰宁卫的四至,大体上是西起锦义,东越辽河,北抵洮河,南及明边。     

Observer-based sliding mode control for a class of discrete systems via delta operator approach

In this paper, an observer-based sliding mode control (SMC) problem is investigated for a class of uncertain delta operator systems with nonlinear exogenous disturbance. A novel robust stability condition is obtained for a sliding mode dynamics by using Lyapunov theory in delta domain. Based on a designed sliding mode observer, a sliding mode controller is synthesized by employing SMC theory combined with reaching law technique. The robust asymptotical stability problem is also discussed for the closed-loop system composed of the observer dynamics and the state estimation error dynamics. Furthermore, the reachability of sliding surfaces is also investigated in state-estimate space and estimation error space, respectively. Finally, a numerical example is given to illustrate the feasibility and effectiveness of the developed method.