基于滑模变结构控制的电动助力转向系统

针对汽车电动助力转向系统，提出滑模变结构控制方法，建立其运动方程，确定了滑模变结构控制器。台架实验结果表明这种滑模变结构控制器与PD控制器相比，其控制方法简单，同时具有更好控制效果。     

半边结构的三维实体在OpenGL中的表示

本文对三维实体造型中的冀边结构和半边结构进行了对比，根据实际应用的特点，采用半边结构，并对其略作修改，增加了一个段结构，对半边结构的三维实体在OpenGL中的表示作了探讨。     

微型热释电红外传感器

报道一种新结构的微型热释电红外传感器，介绍其结构，工艺与性能参数。     

决策问题结构的形式化研究

运用分形理论研究决策问题结构，对决策问题进行形式化描述，定义其结构函数和结构指数，并将决策问题从定性上分为良好结构、未结构化和纯不良结构。给出了关于决策问题结构的几个定理，讨论了决策问题结构化的测度，提出了决策问题简化的判据。     

高压平衡式复合齿轮泵

为减轻液压齿轮泵的径向载荷，提出了一种新型结构的高压复合齿轮泵。由于其结构和工作原理的特殊性，可降低泵的径向载荷，使其综合性能指标得到显著提高     

适合于多种并行计算结构的TRANSPUTER互连结构：HCCTT

本文将提出一种用于Ｔｒａｎｓｐｕｔｅｒ多机系统的Ｈａｍｉｌｔｏｎ回路连接三元树互连结构，并给出其构造算法。这种结构的Ｔｒａｎｓｐｕｔｅｒ多机系统在其通信服务程序的支持下，可以很好地适应扇型，星型，环和超环等多种并行结构的计算，并且系统的并行处理规模可扩充性强。     

并行视频服务器体系结构研究

分析了目前流行的并行视频服务器体系结构：分布式结构、集群式结构、并行通用计算机结构和并行专用视频服务器结构。综合其优点，针对视频应用的特点，提出了可扩展并行视频服务器体系结构，并研制了基于该结构的并行服务系统。     

Web Structure Mining在电子商务网站中的应用

介绍web结构挖掘的概念，并分析基于链接结构的两种重要的Web结构挖掘算法，最后指出其在电子商务网站的应用以提高网站的价值。     

基于复合梁结构的压电-电磁能量收集器研究

能量收集器是解决复杂环境下为无线传感器网络节点供能问题的有效方法之一。针对传统收集器的共振频率高、频带窄等缺陷，设计了一种基于复合梁结构的压电-电磁式能量收集器，并进行了动力学分析与实验研究。首先对该结构进行理论模型建模，建立动力学方程，验证了其结构合理性。之后将该结构与其他传统压电结构进行对比研究，分析了收集器的动力学特性以及发电性能，优化结构参数，并进行了实验验证。研究发现通过复合梁与电磁单元的引入，收集器的工作频带得到了拓宽，改善了其发电性能，有效地使得该结构的一阶与二阶共振频率靠近。实验结果表明：负载电阻为10 kΩ、磁铁线圈间距为7 mm时，该复合梁压电电磁结构收集器具有最优的输出特性，其最大输出功率为20.17 mW,有效工作带宽约为13.40 Hz。     

高层建筑的结构转换层施工技术

高层建筑的结构转换层施工技术张国忱高层建筑的结构转换层是一个建筑物中不同结构形式相连结的关节点，它既是下部结构的“封顶”，又是上部结构的“空中基础”，在整个建筑物结构体系中起着至关重要的连结纽带作用。采取合理的施工方案方法，保证其施工质量，是关系到建...     

青蒿素类化合物与铁卟啉作用机理的量子化学研究(英文)

4种青蒿素类化合物存B3LYP/6-31(d)水平进行几何优化,并确定过氧桥是分子内的活性位点.采用HF/STO-3G基组对青蒿素与铁卟啉的反应机理进行量子化学研究.所得结构参数显示了Fe-N键断裂.同时Fe-O键生成.计算结果与利用分子对接技术得出结果一致,表明在青蒿素类化合物发挥抗疟活性时,亚铁血红索中铁原子靠近过氧桥中的O13,支持了前人提出的15位氢转移反应路径.     

呋喃甲醛缩N4-取代苯基氨(硫)脲定量构效关系的量子化学研究

本文采用Gaussian98程序用量子化学从头算RHF方法对10种呋喃甲醛缩N^4-取代苯基氨（硫）脲药物进行了计算。研究了这10种化合物抗消化溃疡病的生物活性与量化参数间的关系，发现该类药物的生物活性与LUMO轨道的能量和成分有较好的线性关系，表明该类药物在发挥其生物活性时以接受电子为主。呋喃环和羰基区可能是该类药物的活性区域。为此类药物的合成和开发提供了理论基础。     

还原型牛红细胞Cu(I)Zn-SOD的量化计算

运用G94W量子化学程序,在B3YIP/Lan12dz基组的水平上,对于还原型牛红细胞中CU(I)Zn-SOD活性中心进行了从头计算。研究了分子轨道能量,电荷分布,前线轨道的贡献。结果表明:前沿分子轨道能量均为负值,其电子光谱稳定,与金属配位的咪唑环电荷表现正负交替现象。在前线轨道贡献上Cu(I)的占有轨道贡献大,空轨道的贡献小,不易于接受O_O~-自由基的不成对电子。     

Effects of mutations on active site conformation and dynamics of RNA-dependent RNA polymerase from Coxsackievirus B3

Recent crystal structures of RNA-dependent RNA polymerase (3D^pol) from Coxsackievirus B3 (CVB3) revealed that a tyrosine mutation at Phe364 (F364Y) resulted in structures with open active site whereas a hydrophobic mutation at Phe364 (F364A) led to conformations with closed active site. Besides, the crystal structures showed that the F364W mutation had no preference between the open and closed active sites, similar to wild-type. In this paper, we present a molecular dynamics (MD) study on CVB3 3D^pol in order to address some important questions raised by experiments. First, MD simulations of F364Y and F364A were carried out to explore how these mutations at Phe364 influence active site dynamics and conformations. Second, MD simulations of wild-type and mutants were performed to discover the connection between active site dynamics and polymerase function. MD simulations reveal that the effect of mutations on active site dynamics is associated with the interaction between the structural motifs A and D in CVB3 3D^pol. Interestingly, we discover that the active site state is influenced by the formation of a hydrogen bond between backbone atoms of Ala231 (in motif A) and Ala358 (in motif D), which has never been revealed before.     

Conformational analyses and docking studies of a series of 5-nitrofuran- and 5-nitrothiophen-semicarbazone derivatives in three possible binding sites of trypanothione and glutathione reductases

To explore three possible binding sites of trypanothione and glutathione reductase, namely, the active, the dimer interface and the coenzyme NADPH binding site, a series of eight compounds, nitrofurans and nitrothiophenes derivatives, were docked, using their crystallographic and modeled conformations. Docking results showed that, for both families and both enzymes, compounds are more likely to bind in the interface site, even though there is some probability of binding in the active site. These studies are in agreement with experimental data, which suggest that these class of compounds can act either as uncompetitive or mixed type inhibitors, and also with the finding that there is an alpha-helix which connects the active with the interface site, thus allowing charge transference between them.     

A QM/MM study of the catalytic mechanism of aspartate ammonia lyase

Aspartate ammonia lyase (Asp) is one of three types of ammonia lyases specific for aspartate or its derivatives as substrates, which catalyzes the reversible reaction of l-aspartate to yield fumarate and ammonia. In this paper, the catalytic mechanism of Asp has been studied by using combined quantum-mechanical/molecular-mechanical (QM/MM) approach. The calculation results indicate that the overall reaction only contains two elementary steps. The first step is the abstraction of C_β proton of l-aspartate by Ser318, which is calculated to be rate limiting. The second step is the cleavage of C_αN bond of l-aspartate to form fumarate and ammonia. Ser318 functions as the catalytic base, whereas His188 is a dispensable residue, but its protonation state can influence the active site structure and the existing form of leaving amino group, thereby influences the activity of the enzyme, which can well explain the pH dependence of enzymatic activity. Mutation of His188 to Ala only changes the active site structure and slightly elongates the distance of C_β proton of substrate with Ser318, causing the enzyme to remain significant but reduced activity.     

An evaluation of spherical designs for molecular-like surfaces

The use of spherical harmonics in the molecular sciences is widespread. They have been employed with success in, for instance, the crystallographic fast rotation function, small-angle scattering particle reconstruction, molecular surface visualisation, protein-protein docking, active site analysis and protein function prediction. The calculation of spherical harmonic expansion coefficients requires integration over the full sphere and can be a computationally cumbersome and also numerically sensitive (with respect to the integration weights) procedure. It is shown here how the use of spherical t-designs and pre-computed near-equal weight integration layouts can significantly reduce the computational effort in the determination of spherical harmonic expansion coefficients for molecular surfaces, thus giving rise to a robust and highly efficient algorithm for the construction of molecular-like objects.     

CXFTV2: A Fortran subroutine for the discrete least squares convex approximation

A Fortan subroutine calculates the least squares approximation to n data values containing random errors subject to non-negative second divided differences (convexity). The method employs a dual active set quadratic programming technique that allows several concavities of an iterate to be corrected simultaneously, which is a distinctive feature of this calculation. A B-spline representation of the iterates reduces each active set calculation to an unconstrained minimization with fewer variables that requires only O(n) computer operations. Details in these techniques including the data structure that establishes the implementation of the method are specified. Numerical testing on a variety of data sets indicates that the subroutine is particularly efficient, terminating after a small number of active set changes, the subroutine being suitable for large numbers of data. A numerical example and its output is provided to help the use of the software.