新型咔唑衍生物密度泛函理论的研究

运用量子化学中的密度泛函和含时密度泛函理论法,计算1种新型咔唑衍生物,以探讨其几何构型、电子结构、前线分子轨道和电子光谱性质。计算结果表明当2-(4-吡啶基)乙烯基的反式构型与咔唑环作用时比顺式稳定,引入取代基后使化合物的HOMO和LUMO之间的能隙降低,吸收光谱红移。电子被激发时,电子从咔唑环向吡啶环转移,说明新型咔唑类化合物具有很好的光学性能,可以作为空穴传输材料。     

酚类抗氧化剂结构-活性的ab initio研究

采用ab initio方法,在HF/6-31G水平上对4种酚类抗氧剂的平衡几何构型、净电荷及前线轨道组成和能级等进行了理论计算研究,探讨了这些化合物的结构特征、抗氧化活性和取代基效应。研究表明,这些抗氧化剂HOMO和LUMO均为π-分子轨道。由共轭大π-键的离域性和HOMO与LUMO的性质表明,不饱和的共轭体系不仅能与自由基结合,还因共轭体系的孤对电子更易转移而与金属形成配位键和化学吸附膜,添加剂的电子结构性质决定了抗氧作用。研究还表明酚类化合物的抗氧化活性与其释放活泼氢生成苯氧自由基的能力有关,活性大小与O-H间的Mulliken集居数、净电荷差、前线轨道能级和反应终态能量下降量有关。4种酚类化合物的抗氧化活性:化合物Ⅰ>Ⅳ>Ⅱ>Ⅲ,与实验结果一致。     

2-(4-取代苯基)乙烯基吡啶电子光谱的理论研究

对2-(4-取代苯基)乙烯基吡啶系列用密度泛函法(DFT),在B3LYP/6-31+G**冰平上全优化几何构型,探讨苯环对位上不同取代基对分子电荷的转移、前线轨道能量等性质的影响规律.结果,电子由苯环向乙烯链移动,并通过乙烯链再向吡啶环移动;前线轨道能量随着取代基吸电子能力的增加而降低,随着供电子能力的增强而升高.在此基础上采用含时密度泛函(TD-DFT)计算分子第一激发态的电子跃迁能,得到最大吸收波长λmax.计算结果,6个化合物的最强跃迁都由于基态到单重激发态分子的HOMO→LUMO跃迁,由轨道对称性可知为π→π*跃迁.引入上述5种取代基,均导致最大吸收波长红移.     

8-羟基喹啉衍生物密度泛函理论的研究

运用量子化学中的密度泛函理论(TD-DFT)法,在B3LYP/6-31G(d,p)水平上,理论计算两种新型的8-羟基喹啉衍生物,5-[(4-E-苯乙烯基)-苯甲亚胺基]-8-羟基喹啉(1)和5-[(4-溴-2-氟)苯甲亚胺基]-8-羟基喹啉(2).探讨化合物(1)和(2)的几何构型、电子结构、前线分子轨道和电子光谱性质.结果表明由于引入取代基使体系的HOMO与LUMO之间的能隙降低,增强了与金属铝配位的能力;电子吸收光谱与实验数据基本吻合.     

典型三环杂环化合物电子结构和性质的DFT研究

采用杂化的DFT理论,研究了6种典型三环稠杂环化合物的几何结构、电子密度拓朴结构、NICS以及HOMO-LUMO能级差、电子亲和势和电离能等性质。研究表明,6种三环化合物均为平面结构,分子体系中所有化学键都具有π键特征,环平面上存在较强的共轭作用。这6种化合物具有较小的HOMO-LUMO能级分离值(2.22 eV～3.71 eV),较大的电子亲和势和较大的电离能。因此,在导电聚合物分子设计中,三环杂环化合物可作为良好的电子受体引入共轭聚合物分子。三环杂环化合物结构单元的引入将有利于加强体系π电子的离域,降低聚合物的能隙和增加聚合物体系还原掺杂态的稳定性。     

烷基化芳胺抗氧抗腐添加剂分子结构特性的理论研究

采用量子化学方法,在B3LYP/6-31G~*水平上对8种烷基化芳胺抗氧抗腐添加剂的平衡几何构型、净电荷及前线轨道组成和能级等进行了理论计算研究,探讨了这些化合物的结构特征。研究表明,这些添加剂胺基和苯环形成的共轭平面构成了活性部位,其HOMO和LUMO均为π-分子轨道。由共轭大π-键的离域性和HOMO与LUMO的反应性预测表明,不饱和的共轭体系不仅能与氧自由基结合,还因共轭体系的孤对电子更易转移而与金属形成配位键和化学吸附膜,添加剂的电子结构性质表明具有抗氧抗腐蚀性能。     

2,5位双侧基取代对聚对苯撑乙炔低聚物光学性质调制作用

利用密度泛函理论方法,分别以氰基、羧基和氨基、羟基典型的小分子推拉电子基团为例,对2、5位双侧基取代对聚对苯撑乙炔低聚物（n=1~10）吸收光谱的调制作用进行了理论预测。推拉电子基团的引入均使聚对苯撑乙炔衍生物的特征吸收发生规律性红移,红移程度与推拉电子的相对能力有关,跃迁强度的变化与基团的电荷布居相对转移程度相关。通过电子结构和跃迁轨道等激发态性质分析得出推拉电子基团对聚对苯撑乙炔轨道能的调制机理不同。可以预测侧基推拉电子基团的引入对聚对苯撑乙炔吸收光谱影响结果与基团的推拉电子能力和结构特征等因素相关,希望此结论能为聚对苯撑乙炔衍生物和类似体系光谱性质的有效调制等实验研究提供理论支持。     

丹参酮分子结构及光谱性质的理论研究

采用量子化学密度泛函理论(DFT)在B3LYP/6-31G水平上对丹参酮Ⅰ、丹参酮ⅡA、隐丹参酮3个典型的丹参酮类化合物分子几何构型进行优化,分析分子前线轨道能级及分布特征.用含时密度泛函理论(TD-DFT)在相同水平对上述化合物分子进行电子吸收光谱研究.并且以乙醇为溶剂,计算其对分子结构和光谱性质的影响.计算结果表明:丹参酮Ⅰ分子骨架发生共轭形成大π键,为刚性的平面分子结构;丹参酮Ⅰ、丹参酮ⅡA、隐丹参酮分子共轭体系依次缩小.分子HOMO-LUMO能隙随着分子共轭体系的减少而增大.3个分子的九λmax均主要来源于电子的π→π跃迁.乙醇对上述化合物分子结构和光谱性质有一定影响,吸收光谱均发生红移.同时还发现,乙醇改变了丹参酮Ⅰ的λmax主要电子跃迁来源轨道.丹参酮Ⅰ在气相条件下λmax主要来源于分子中的HOMO→LUMO+2的π→π跃迁;而在乙醇中λmax主要来源于HOMO-5→LUMO的π→π跃迁,该跃迁存在明显的分子内电子转移现象.     

C60-P-三苯硼嗪单对位取代物的结构和电子性质的AM1研究

利用半经验AM1法研究了富勒烯C_(60)-P-三苯硼嗪单对位(110号位次)取代物的几何构型、电子结构和相关能量。研究结果显示,富勒烯C_(60)-P-三苯硼嗪单对位取代物中的侧链与C_(60)发生作用,并向C_(60)部分呈弯曲状态,从而形成一种独特的半包裹C_(60)的空间构型体系。而且它们的HOMO轨道主要分布在三苯硼嗪部分,而LUMO轨道则主要分布在V_(60)上.理论预测连有供电子基(-CH_3)的C_(60)-P-三苯硼嗪单对位取代物很有可能在激发态下产生更长寿命的电荷分离态.     

共轭性取代对咔唑类衍生物结构和光谱性质影响的理论研究

用密度泛函理论(DFT)和含时密度泛函理论(TD。DFT)对咔唑的6种共轭基团取代衍生物的电子结构和吸收光谱性质进行了比较研究。对衍生物的基态分子结构运用B3LYP/6-31G(d)水平进行全优化,分析了电荷的分布和前线分子轨道等性质。结果表明,与母体咔唑相比,各衍生物均形成了分子内氢键,共轭体系的π键成分增大,能级差减小,激发能降低,分子的最大吸收波长向长波方向移动,即发生红移。前线分子轨道分析表明该类化合物吸收光谱主要对应分子中的HOMO→LUMO电子跃迁,且为π-π~*跃迁。共轭性基团的引入扩大了分子结构的共轭范围,增强了分子内电子的转移,改善了咔唑类化合物的光电性能。本文为新型含咔唑基团的光电功能材料的设计合成提供了理论参考。     

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。     

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.     

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.     

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     

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.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。