醇类化合物疏水性参数的分子拓扑研究

分子中原子i的均价（δi^a)定义为δi^a=(δi^v ∑nijδij^v)/(1 ∑nij)。在分子图的邻接矩阵基础上建构均价连接性能指数（^mK）。其中^lK对醇类化合物呈现良好的结构选择性，并与56个醇类化合物的疏水性参数（log^P)具有较好的相关性。与60中脂肪醇的logP的线性相关系数为0.9948。这两项均优于相应的文献方法。     

化整矩阵为整Hessenberg型的一种整相似变换

文[1]所述通过整相似变换把整矩阵A=(α_(ij)_(n×n)化为整上Hessenberg矩阵的过程可以被改进。为此我们建立以下引理: 引理。设n_1,n_2,是两个不为零的整数,那么存在整矩阵(a b c d),使得     

超分子连接性指数对醇类化合物定量结构-保留关系研究

基于分子间弱相互作用,提出一种拓扑指数——超分子连接性指数,运用该指数对醇类化合物定量结构-保留关系进行了研究。结果显示超分子连接性指数~1X_P和~6X_(Pc)与醇类化合物保留值显著相关,相关系数高达0.99。表明超分子连接性指数可成功用于醇类化合物的定量结构一保留关系研究。     

二芳基咪唑类化合物选择性环氧合酶-2(COX-2)抑制性的QSAR研究

应用HyperChem7.0计算与二芳基咪唑类化合物选择性环氧化酶(COX-2)的抑制性相关的量化参数以及自己设计的结构编码参数,对52种1,2-二芳基咪唑化合物的抑制性做QSAR研究.使用逐步回归筛选出影响抑制性的主要参数分子偶极矩μ、分子疏水参数logP和编码参数R2、R5和R7建立QSAR方程.经留三法验证,检验结果相关系数R为0.9155,剩余标准偏差s为0.3601,与回归拟合得到的R=0.9357,s=0.3157接近,表明所建QSAR方程预测效果较好,稳定性较高.对筛选参数的分析表明,μ、logP主要通过影响化合物的脂溶性,R2、R5通过影响化合物的空间结构,R7则通过化合物与COX-2对应活性位点氢键作用的变化,分别对化合物对COX-2的抑制性产生影响.     

用矩阵法进行触点的设计计算

1972年9月18日“Design News”发表的一篇文章“用矩阵法计算梁的挠度”,概述了在载荷作用下得到梁的挠曲方程式的方法。一个复杂的梁可划分为若干个简单的部分。用卡氏定理确定各部分梁的几何关系式,因而采用广义内力qi。并利用这些力的系数来建立挠性系数矩阵[α_(ij)]。描述实际外加载荷同广义内力的关系的一组平衡方程式是单位载荷矩阵[G_(jm)]的基础。由下式得到影响系数矩阵[A_(mn)]: [A_(mn)]=[G_(mj)]×[α_(ij)]×[G_(jm)] 挠度矩阵[δ_m]由[A_(mn)]与载荷矩阵[P_n]相乘得到: [δ_m]=[A_(mn)][P_n] 本文把上述方法推广用到触点设计中遇到的复杂梁的计算问题。各种梁的一览表及表征其几何特性的“α_(ij)”是分析复杂梁的基础。由计算机将相应的矩阵相乘就得到载荷挠曲曲线。     

量子化学参数用于脂肪族化合物分配系数的QSPR研究

采用ChemOffice 8.0中的MOPAC-AM 1量子化学方法计算149种脂肪族化合物的6种量子化学参数,取142个化合物作为样本集,用多元逐步回归分析法建立定量结构相关(QSPR)模型.模型能预测好脂肪族化合物的正辛醇/水分配系数(logP).logP平均误差为0.176个对数单位,模型的稳健性检验结果表明,模型中自变量无相关关系,残差呈正态分布.预测7个样本以验证模型,表明该模型的预测能力较好.     

N(2,2,0)代数的(∈~δ,∈~δ∨q~δ_(λ,μ))-模糊理想

将模糊点和模糊集间的"∈(属于)"和"q_(λ,μ)(广义重于)"关系推广为"∈~δ(Ω-属于)"和"q_(λ,μ)~δ(Ω-重于)"关系,提出了(∈~δ,∈~δ∨q~δ_(λ,μ))-模糊代数。将(∈~δ,∈~δ∨q~δ_(λ,μ))-模糊代数与N(2,2,0)代数相结合,给出了点态化(∈~δ,∈~δ∨q~δ_(λ,μ))-模糊理想和Ω_(λ,μ)-模糊理想的概念,证明了两者之间的等价关系,研究了它们的一些基本性质;最后提出了点态化(∈~δ,∈~δ∨q~δ_(λ,μ))-模糊子代数和Ω_(λ,μ)-模糊子代数的定义,研究了(∈~δ,∈~δ∨q~δ_(λ,μ))-模糊理想和(∈~δ,∈~δ∨q~δ_(λ,μ))-模糊子代数的相互关系。     

五员杂环化合物的量子化学理论研究

五员杂环及衍生物是重要的工业原料,有些具有重要的生理作用。为了探讨此类化合物结构特点、化学位移与活性之间的关系,本文采用密度泛函B3LYP和从头计算ab initio HF、MP2方法研究了呋喃、吡咯、噻吩的几何构型,用TD-DFT方法对分子的电子光谱进行了计算,运用GAIO-HF计算了分子的化学位移,并将计算数据与实验值进行比较。结果表明：(1)选用MP2对此类化合物键长键角更为适宜；(2)三种化合物电子光谱的最大吸收波长很接近,溶液的计算值优于气相的；(3)分子的化学位移与反应活性有密切联系：化合物α位氢原子的δ_H值愈小,该化合物亲电取代反应活性愈高；同一杂环分子,氢原子的δ_H值愈小,该位置的亲电取代反应活性愈高。     

类黄酮化合物抑制恶性疟原虫的预测模型

建立预测类黄酮化合物抑制恶性疟原虫株活性定量的模型,并确定影响类黄酮化合物活性的主要因素。本文选用了38个结构不同的类黄酮化合物作为数据集,采用多元线性同归法及主成分分析法分析每个化合物的220个分子参数,建立最优的预测模型。比较用不同方法建立的模型,结果发现带logP参数的向后筛选法为最优方法,所建模型统计结果良好(训练集相关系数R~2=0.81,标准训练误差SEE=0.27),模型代入检验集数据时结果也令人满意(检验集相关系数R~2=0.83,标准检验误差SEP=0.39),可靠性和预测性较强。脂水分配系数的对数logP为模型重要影响参数。建模和确定影响因素有助于筛选新型类黄酮抗疟疾药物和研发。     

梅森公式在多回路控制系统中的应用

直观回路是指系统方块图中显而易见的只穿过被控对象一次的回路。如图1,它只有两个直观回路:δ_1→X_2(s)→A→δ_1和δ_2→X_1(s)→B→δ_2。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate