催化合成水杨酸甲酯的热力学计算与分析

利用Benson基团贡献法计算了水杨酸甲酯的热力学数据△_fH~θ和C_p,对甲醇和水杨酸催化合成水杨酸甲酯反应体系进行了热力学分析,通过对反应自由能变化△,G、平衡常数K_p以及水杨酸的平衡转化率的计算分析,结果表明该反应为吸热反应,其吉布斯自由能变化为负值,水杨酸甲酯可以得到较高的转化率,为催化合成水杨酸甲酯的研究提供了热力学数据。     

COS和H_2S毒化F-T合成催化剂热力学分析

利用热力学基础数据和相关软件对F-T合成催化剂COS和H_2S中毒的热力学进行了计算。在热力学上,Ru、Fe、Co的COS中毒在F-T合成反应可以发生的条件下均是自发过程。F-T合成反应体系中10~(-9)级的COS即可使Ru基催化剂中的金属Ru生成RuS_2而中毒。Fe和Co毒化后生成的硫化物种类较多,对这些反应的热力学计算结果表明,对于不同的反应,其平衡常数的差异很大,对应中毒反应发生时,所需的COS和H_2S的浓度也不同,对COS的要求更为严格。由于Fe基F-T合成催化剂活性相的复杂性,利用对催化剂相关性质的修饰开发具有一定抗硫性的铁基F-T合成催化剂是可行的;对于Co催化剂,利用F-T合成的反应特点和催化剂改性开发具有一定抗硫性催化剂是可能的。     

叠氮酸与氨氰环加成反应的理论研究(英文)

采用B3LYP、QCISD、MP2方法在6-311+G(d)基组水平上对叠氮酸与氨氰环加成反应进行了详细研究。首先对所有的反应物、过渡态和产物的构型进行了全参数优化,并用频率分析和内禀反应坐标(IRC)方法对过渡态进行确认。以步长为0.1(amu)1/2 bohr的内禀反应坐标方法在B3LYP/6-311+G(d)方法和基组水平上计算了内禀反应坐标s为(-3.00～3.00)(amu)1/2 bohr范围内反应的键长、振动频率、NBO电荷变化情况。根据统计热力学方法和用Wigner校正的Eyring过渡态理论,计算了(200～450)K温度范围内反应热力学函数及速率常数,探讨了温度对反应的影响。结果表明,反应经过过渡态TS生成5-AT的活化能为117.14 kJ/mol(B3LYP)、130.18 kJ/mol(QCISD)和106.24 kJ/mol(MP2),产物的相对能量为-74.24 kJ/mol(B3LYP)、-87.01 kJ/mol(QCISD)和-79.09 kJ/mol(MP2);反应随温度的升高更具有动力学优势,但在热力学上低温下更易于进行,因此,结合热力学和动力学因素,我们认为(300～350)K是该反应的适宜温度。     

乙酸丁酯反应精馏过程模拟设计

反应精馏偶合了反应和精馏两种单元操作,通过精馏促进反应,可以提高反应转化率和收率,为可逆反应的化工过程生产提供了新的设计途径。基于严格热力学分析计算,利用计算机模拟和优化手段。提出了乙酸丁酯反应精馏、分离纯化的生产流程。采用UNIQUAC方程表征乙酸-正丁醇-乙酸丁酯-水四元非理想体系的汽液平衡,首先,根据实验数据回归了热力学模型中的交互作用参数,并预测了体系中5个共沸物组成,模型的计算结果与实际数据吻合。基于平衡级模型,提出了由平衡反应器、反应精馏塔、倾析器和纯化塔构成的可行流程,对提出的设计流程进行了模拟、优化,得到了操作工艺参数。模拟结果对工业过程的设计和改造具有一定的指导意义。     

丁酮-醋酸异丙烯酯等压汽液平衡数据的测定和关联

为了给醋酸异丙烯酯异构化制乙酰丙酮工艺的产物分离提供基础热力学数据,用改进的埃利斯(Ellis)平衡蒸馏器测定了常压下丁酮-醋酸异丙烯酯体系的汽液平衡数据。结果表明,实验数据经Herington面积法热力学一致性检验。采用活度模型Wilson方程和NRTL方程对实验数据进行了关联,计算结果与实验数据均较为吻合。同时关联得到了两方程的模型参数,可满足工程设计的需要。     

硅苯与腈氧化物1,3-偶极环加成反应的理论研究

采用密度泛函理论(DFT)方法在B3LYP/6-311G(d,p)水平研究了硅苯与腈氧化物的1,3-偶极环加成反应的微观机理、势能剖面,考察取代基和四氢呋喃溶剂对反应势能剖面的影响。计算结果表明,所研究反应均以协同但非同步的方式进行,且总是Si-O键先于C-C键形成。硅苯分子中Si原子上的给电子和吸电子取代基均有利于反应的进行,而腈氧化物碳原子上的2,4,6-三甲基苯基取代基在热力学上对反应非常不利。四氢呋喃溶剂对所研究反应的势能剖面影响不大。     

离子电极法测定NaCl—KCl—H2O体系中NaCl,KCl的平均活度系数

NaCl—KCl—H_2O 体系广泛分布在生物体液,海洋湖沼,特别是盐湖盐矿中,它的生理作用,成矿规律和盐湖资源综合利用研究中均需了解该体系的热力学性质,而体系的热力学数据的推导与平均活度系数密切相关。测定活度系数的方法主要有溶解度法、等压法、冰点法和电动势法。Robinson 早在1961年就用等压法计算了该体系中 NaCl、KCl各自的 Harned 系数,Holmes 等也用等压法详细研究了该体系在不同温度下的热力学行为。Bulter 等首先用钠汞齐电极测定了该体系中 NaCl 的平均活度系数,由于钠、钾离子迁移反应带来的动力学的干扰,实验结果不甚理想,稍后他们采用了商品钠玻璃电极,     

Co-Mo-K催化剂上COS、HCN转化率的热力学分析

利用热力学基础数据和相关软件对Co-Mo-K催化剂上COS、HCN加氢和水解反应进行了热力学计算。在热力学上,COS、HCN加氢和水解反应在耐硫变换条件下均为自发过程。计算结果表明在Co-Mo-K耐硫变换条件下COS、HCN主要发生的是水解反应,该结果与工业经验数据基本一致,可以作为工业实际借鉴。     

Pitzer 模型在Na+//Cl-,SO24——H2O体系中多温适用性研究

不同温度下的Na+//Cl-,SO2-4,H2O体系液固平衡是芒硝和盐生产过程重要的理论基础,其应用方面的研究工作进行得较多,而多温下热力学的研究尚未见报道.本文采用Pizter离子相互作用模型理论,建立了上述体系热力学模型;利用该模型对上述体系在不同温度下的溶解度进行了预测,并与实验数据对比,研究了Pizter离子相互作用模型理论对于本体系多温情况的适用性.本文利用Pizter理论中的温度系数以及不同温度下该体系的溶解度实验数据,通过Matlab优化函数获得不同温度下各盐的活度积和两离子、三离子混合作用参数,并利用Matlab非线性方程求解函数,预测该体系0-150℃范围内的液固平衡数据,并与实验数据对比.研究结果表明Pizter模型的多温适用性良好,预测结果与实验数据基本一致,对生产实践有一定指导意义.     

Pitzer模型在Na~ //Cl~-,SO_4~(2-)-H_2O体系中多温适用性研究

不同温度下的Na //Cl-,SO42-,H2O体系液固平衡是芒硝和盐生产过程重要的理论基础,其应用方面的研究工作进行得较多,而多温下热力学的研究尚未见报道。本文采用Pizter离子相互作用模型理论,建立了上述体系热力学模型;利用该模型对上述体系在不同温度下的溶解度进行了预测,并与实验数据对比,研究了Pizter离子相互作用模型理论对于本体系多温情况的适用性。本文利用Pizter理论中的温度系数以及不同温度下该体系的溶解度实验数据,通过Matlab优化函数获得不同温度下各盐的活度积和两离子、三离子混合作用参数,并利用Matlab非线性方程求解函数,预测该体系0-150℃范围内的液固平衡数据,并与实验数据对比。研究结果表明Pizter模型的多温适用性良好,预测结果与实验数据基本一致,对生产实践有一定指导意义。     

Chiral liquid‐crystalline 3,6‐disubstituted cyclohex‐2‐enones and their derivatives and the FLC compositions based upon them

Abstract— The synthesis and chemical transformations of the 3,6‐disubstituted cyclohex‐2‐enones into new chiral liquid‐crystalline lateral substituted derivatives of biphenyl, terphenyl, or quaterphenyl are presented. The mesomorphic properties of the prepared compounds and physical and electro‐optical parameters of FLC compositions based upon them are discussed here, emphasizing structure‐property relations.     

The liquid‐crystalline derivatives of 3,6‐disubstituted cyclohex‐2‐enones

Abstract— A new synthetic approach for the preparation of various mesomorphic chiral and non‐chiral derivatives of cyclohexene, cyclohexane, phenylcyclohexane, or biphenyl with different combinations of cyclic, bridge, terminal fragments and lateral substituents is proposed and realized. Both nematic and smectic liquid‐crystalline compounds were prepared by the transformations of the corresponding 3,6‐disubstituted cyclohex‐2‐enones.     

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     

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.