一个基于J2EE Web应用的框架设计与实现

J2EE(Java 2平台企业版)是当前建立和开发各种Web应用的主流平台,MVC(模型-视图-控制)体系结构是当今设计交互式应用的事实标准.文中结合MVC在J2EE Web中的应用,通过电子政务系统开发实践,提出了一个具体的实现方案,描述了应用系统设计,给出了表示层、控制层、代理层、业务逻辑层、数据访问层和数据存储层等层次的明确划分,阐述了各层的功能作用以及层与层之间的关系,并针对具体业务给出了实现的部分具体内容,为在J2EE环境下开发结构良好、易于维护、易于扩展的Web应用提供了可行方案.     

Studies of substrate specificities of lipases from different sources

Although lipases are widely applied in a wide variety of reactions, available information on the factors that are responsible for the substrate specificities of lipases from different sources is scarce. In this paper, nine lipase‐producing microorganism strains were isolated from oil‐containing samples. The properties of these enzymes, including pH optima, temperature optima, thermal stability, and pH stability, vary significantly with the different sources from which these lipases were isolated. The substrate specificities of the nine lipases, including fatty acid and positional specificities, were also studied. The fatty acid specificities of the nine lipases were observably different toward 15 substrates with different carbon chain lengths, different saturation degrees and different side chains. The lipases from S₃ Penicillium citrinum (PCL), MJ₁ Aspergillus niger (ANL), MJ₂ Aspergillus oryzae (AOL), YM Bacillus coughing (BCL), S₉ Geotrichum candidum (GCL), and S₁₁ Candida lypolytica (CLL) showed the strongest specificities to short‐chain esters, and the other lipases showed strong selectivity for medium‐ or long‐chain and branched esters. The positional specificities were examined by analyzing the hydrolytic products of triolein catalyzed by the nine lipases, using TLC. The lipases can be mainly classified into two groups by their specificities for the ester bond at position 2 of triglycerides; one group can selectively hydrolyze the ester bond at position 2 of the triglycerides, the other group cannot. All these nine lipases were divided into four groups by hierarchical clustering analysis on the basis of the results of fatty acid and positional specificities.     

一种T形高压输电线路故障测距新方法

对T形线路的故障测距，现有方法都是先判断故障支路，再将3端线路等效成2端线路进行测距。但在 T节点附近短路，尤其是经高阻短路时，现有的测距方法由于无法正确判别故障支路而存在一定范围的测距死区。针对上述缺陷，分别假设故障发生在某一支路，由假定正常的2段支路端的电压、电流推算求得 T节点电压和注入假定故障支路的电流，从而分别求得3个故障距离。经证明，求得的3个故障距离有且仅有1个在0和对应支路总长度之间，该距离就是真实的故障距离，故障发生在对应支路上。该方法无需事先判别故障支路即可测距，在 T节点附近经高阻故障时无测距死区。其测距精度理论上不受过渡电阻和故障类型影响，无需故障前数据，且对滤波无高要求。EMTP仿真结果表明该方法正确、有效，测距精度高。     

变频调速器在桥式抓斗吊车中的应用

论文主要介绍了电机的调速方法、变频器的工作原理以及日本FRNIC500G7型变频器在桥式抓斗吊车上的应用，并分析了使用绕线式电机调速与鼠笼式电机变频调速之间的优缺点。     

La改性的Ag/TS-1催化剂上丙烯选择氧化制环氧丙烷

在H2 和O2 混合气体存在下 ,在常压固定床、石英反应器上考察了La改性的Ag/TS - 1催化剂催化丙烯环氧化反应。研究结果表明 ,Ag和La负载在TS - 1上的先后顺序对丙烯环氧化反应有影响。H2 在丙烯气相氧化反应体系中起着重要的作用。     

连续箱梁桥中跨合龙段劲性骨架优化设计

结合某连续箱梁桥悬臂施工实践,对中跨合龙段劲性骨架设置和受力进行了分析,推导了劲性骨架设计的理论计算公式,并分析了劲性骨架刚度大小对桥梁整体结构的影响。     

一种转移脉冲宽度可调的CCD驱动电路

本文以TCD132D线阵CCD为例,介绍了一种用循环计数器和拨码开关共同作用改变CCD转移脉冲的CCD驱动电路。该电路结构简单,工作可靠,调整方便。     

直接斜率波前复原算法的控制效果分析

建立自适应光学系统功率谱抑制函数的概念，分析了采用直接斜率波前复原算法的自适应当光学系统的控制效果，理论分析与６１单元自适应光学系统上的实验结果表明，直接斜率波前复原算法将导致控制效果下降。     

A comprehensive study of performance and reliability of P, As, andhybrid As/P nLDD junctions for deep-submicron CMOS logic technology

A comprehensive study of P, As, and hybrid As/P nLDD junctions is presented in terms of performance, reliability, and manufacturability for the first time. It is found that As junctions limit the performance of deep submicron devices due to unacceptable hot-carrier reliability, whereas a hybrid junction (light dose P added to medium dose As) dramatically improves hot-carrier reliability while maintaining high performance and manufacturability. For L_eff of 0.19 μm, using this hybrid junction in a manufacturing process, an inverter gate delay of 32 ps, dc hot carrier life time exceeding ten years, and off-state leakage below 30 pA/μm at 2.9 V have been achieved     

柔性制造系统的负荷分配及路径规划方法

柔性是柔性制造系统（ＦＭＳ）的一个基本优点，但这一基本优点却往往被人们忽视，许多现在运行的ＦＭＳ不是缺乏柔性，就是没能充分利用可获得的柔性来提高生产效率。柔性制造系统的负荷分配和路径规划问题正是这种柔性的一个主要方面，然而，路规划决策却往往被。其中一个主要原因人们仍不能从传统的生产管理概念中解放出来。本文在明确概念区分的基础上，提出了一种柔性制造系统的负荷分配和路径规划的线性规划模型，其主要特点是