脂肪胺类化合物脂水分配系数的QSPR研究(英文)

用16种脂肪胺类化合物HF/6-31G**,HF/6-311G**,DFT-B3LYP/6-31G**和DFT-B3LYP/6.311G**全优化计算结构参数:分子最高占用和最低空轨道能(EHOMO和ELUMO),分子次最高占用和次最低空轨道能(ENHOMO和ENLUMO),分子总能量(ET),氢原子所带的最高正电荷(qH+),最负原子的静电荷(q-),分子偶极矩(μ)和分子体积(V),对它们的脂水分配系数(lgKOW)分别进行定量构效关系(QSPR)研究.结果表明:脂肪胺的lgK与分子最低空轨道能(ELUMO),分子的总能量(ET)和分子偶极距(μ)的相关性较好,成功地建立了lgKOW的QSPR方程.特别是基于B3LYP/6-311G**基组建立的方程具有更好的[[预]能力,并通过VIF值和t值对其稳健性进行了检验,结果良好.     

C6H6和SO3相互作用的理论研究（英文）

采用B3LYP和MP2方法在6-31G*、6-31+G*和6-311+G**基组下对C6H6…SO3复合物体系的4种可能结构进行自由优化,得3种。在考虑基组重叠误差校正基础上,得结合能,并用自然键轨道分析方法讨论其相互作用。结果表明,用B3LYP/6-31G*计算3种复合物的结合能分别为-17.75, -18.33, -18.80 kJ/mol,且C6H6和SO3结合时电子从苯环向SO3转移,形成电荷转移复合物,它们之间的作用包含π-p作用方式。     

丙烯酸正丁酯聚合的Diels-Alder反应机理理论研究

本文从理论上对丙烯酸正丁酯(nBA)自引发聚合的Diels-Alder反应机理进行了研究.利用DFT方法在UB3LYP/6-31G*水平上对反应的最低能量路径进行了计算,各驻点能量分别采用MP2/6-311G**和B3LYP/6-311 G(3df;2p)进一步精确计算.结构表明:此Diels-Alder反应仅包括一种途径,即路径(I),另一条途径在热力学不支持.     

C3N3(NH2)3、[C(O)NH]3和水双分子间的氢键相互作用

采用密度泛函理论,在B3LYP/6-311+G**水平上对C3N3(NH2)3、[C(O)NH]3、H2O 3种单体在气相中形成的双分了氢键作用体系进行构型优化和频率计算.通过几何优化得到一系列含多个氢键的复合物.频率分析表明,与单体相比,体系形成氢键作用后,参与氢键形成相关的键的红外谱带位置和振动强度都发生明显的变化,其中C3N3(NH2)3-[C(O)NH]3体系中N8-H9键的红移最明显.同时,通过B3LYP/6-311+G**和MP2/6-311+G**水平计算的含基组重叠误差(BSSE)校正的氢键相互作用能分析表明,C3N3(NH2)3-[C(O)NH]3氢键体系的相互作用能最大,其次是([C(O)NH]3)2体系,采用MP2/6-311+G**方法计算的相互作用能分别达到-14.171 kcal·mol-1和-10.217 kcal·mol-1.另外,通过自然键轨道理论揭示氢键相互作用的本质.     

DFT法研究取代芳烃对发光菌的急毒性

用DFT-B3LYP方法,分别在较高基组6-31G**和6-311G**水平下,全优化计算了24种卤苯、苯酚和苯胺衍生物.从中获得分子最高占用和最低空轨道能(EHOMO和ELUMO)、分子次最高占用和次最低空轨道能(ENHOMO和ENLUMO)、分子总能量(ET)、氢原子所带的最高正电荷(QH+)、最负原子的静电荷(Q-)、分子偶极矩(μ)和分子体积(V)等描述符.结合文献标题物对发光菌的毒性值(-lgEC50),由多元线性回归方法获得令人满意的QSAR模型,复相关系数R2和交叉验证系数Q2分别为0.9604和0.8946.模型结果显示:ELUMO越小,即最低空轨道能量越低,分子越易接受电子与亲核试剂发生反应,化合物对发光菌的毒性越大;分子的体积越大,μ越小,化合物毒性越大.     

树状分子聚酰胺胺(PAMAM)的量子化学研究

采用传统的Hartree-Fock(HF)从头算和密度泛函B3LYP方法,选择不同的基组水平(3-21G,6-31G*)对以乙二胺为核的1.0代PAMAM分子进行全几何优化,并对结果进行比较,同时与实验值进行对照.结果表明,B3LYP/6-31G*方法得到的结果更可靠.B3LYP/6.31G*计算结果表明,1.0代PAMAM分子构象不完全对称,4个支链基本在一个平面上,伯胺,仲胺和叔胺上的N原子所带负电荷数逐渐减少,HOMO轨道主要集中在核上,核极易发挥供电子作用.     

十二胺捕收剂溶剂化效应及其水相氢键超分子作用的密度泛函研究

采用密度泛函方法研究了十二胺在气相、苯、乙酸、乙醇及水中的分子构型、电荷分布以及前线轨道。首先采用B3LYP/6-31G(d,p)及B3 LYP/6-311++G(d,p)进行优化,采用自洽反应理论(SCRF)的极化连续介质模型(PCM)进行不同溶剂条件下的优化并进行自然键轨道(NBO)分析。结果表明,对比气相条件下,十二胺分子的几何构型发生了微弱变化,这种变化随着溶剂介电常数的增加长程稳定性增强,溶剂化效应使前线轨道中HOMO趋于比LUMO更稳定,NBO分析表明溶剂化能主要来源于LP(1)N_(38)→π~*C_(32)-C_(33)。随着溶剂介电常数的增加,十二胺分子采用B3 LYP/6-31+G(d,p)的△E_(HOMO)-E_(LUMO)由气相-0.23773 a.u至水相中-0.25120 a.u,溶剂化能-13.36 kcal/mol,采用B3 LYP/6-311++G(d,p)的△E_(HOMO)-E_(LUMO)由气相-0.22755 a.u至水相中-0.24004 a.u,溶剂化能-13.02 kcal/mol,溶剂化能趋于稳定,表明十二胺分子的溶剂化效应采用B3 LYP/6-31+G(d,p)构型趋于稳定。采用B3LYP/6-31+G(d,p)对十二胺与水分子氢键超分子结构进行了研究,利用分子静电势(MEP)进行氢键及反应活性位分析,结果表明氢键作用是引起十二胺分子结构和性质变化的主要原因。研究结果对十二胺捕收剂在溶剂条件下对矿物的浮选机理认识具有一定的理论意义。     

1-甲基环丙烯进入α-环糊精分子组装的理论研究(英文)

本文用密度泛函理论(DFT)和PM3方法研究了1-甲基环丙烯(1-MCP)与α-环糊精(α-CD)包合物形成机理。用B3LYP/6-31G*法优化了α-CD和1-MCP的几何结构,并用PM3方法优化了所有包合物的初始几何结构,结果得到了1-MCP从2个不同端口进入α-CD形成包合物的2个能量最低的结构。在B3LYP/6-31G*水平对这2个能量最低结构的能量、氢键相互作用、Mulliken电荷转移、前线分子轨道进行了分析。结果表明,1-MCP从大口端进入α-CD空腔能量更低。最后,用B3LYP/6-31G*法计算了包合物的红外光谱。     

比较不同基函数下氯化四苯基铁卟啉的B3LYP计算研究

用Gaussian98W程序的密度泛函B3LYP方法,在STO-3G~*、6-31G(d)、6-31G(2d)、6-311G、6-311G(2d,2p)水平,对血红素模拟物氯化铁卟啉分子Fe(TPP)Cl进行了汁算,对分子的结构、电荷密度和自旋密度分布傲了详细对比分析。4个较大基函数计算的能级情况接近,相对较小的6-31G(d)基函数就可以得到较好的计算结果,并且计算时问比用6-311G(2d,2p)基函数少很多。4个较大基函数计算的分子轨道结构几乎完全相同,但6-311G(2d,2p)得到的能级次序与其他大基函数稍有不同。6-311G类基函数的结果较6-31G类基函数有更明显的Fe-卟啉环问的电子转移。根据本文计算结果,6-31G(d)基函数可以利用较少的计算机资源在较短时间内给出不差的结果。     

密度泛函理论和从头计算法研究环戊二烯衍生物气态酸度及其取代基效应

用B3LYP／6-311G(2df,p)／／B3LYP／631 G*和MP2／6-311G(d,p)／／B3LYP／6-31 G*方法准确地预测了9个系列的环戊二烯衍生物(R=CN,CF3,CHO,C283,F,SiH3,H,CH3,OH,NH2)的C-H键的酸度。环戊二烯衍生物气态酸度的范围从284.9 kcal／mol (化合物5a)到357.24kcal／mol(化合物7j),分析取代基的电性、数量以及位置的影响得到了9个QSAR方程。这些数据有助于我们设计以及合成一些有机酸,并有助于深刻理解相关反应中环戊二烯衍生物的性质。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

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.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.