密度泛函法研究几种甲基乙烯基硅橡胶初级交联链结构的辐射稳定性

借助于用密度泛函理论的第一性原理方法,研究了由硅橡胶材料的2种主要单体二甲基硅氧烷和甲基乙烯基硅氧烷所构成的4种初级交联链结构的化学构型、前沿轨道及相关能量、拉曼振动分析等信息。研究结果显示,交联链结构的波动性明显不如次级链结构;链结构中的原子排布可形成共轭或等效于共轭的离域结构时,可在遭受辐射等能量注入时将能量及时转移而在一定程度上避免其所在链结构的断裂;链结构发生裂解时的位点在共轭链段间隙或孤立乙烯基处的可能性较大;乙烯基的引入在一定程度上可以增加材料本身的化学稳定性却并非一定可以增强材料的辐射稳定性。     

SAW膜材料HFIP功能化PS-b-PMPS的合成与吸附研究

探讨了六氟代异丙醇(HFIP)功能化聚苯乙烯/聚甲基苯基硅氧烷嵌段共聚物(PS-b-PMPS)的合成与涂膜方法.采用无水解缩聚方法合成了环状聚甲基苯基硅氧烷,阴离子聚合制备了窄分子量分布(Mw/Mn=1.99)的PS-b-PMPS,与六氟丙酮反应得产物。用IR、GPC、乌氏粘度计等方法进行表征。用旋涂法涂膜,2,4-二硝基甲苯(2,4-DNT)进行检测,结果表明2,4-DNT浓度为750mg/m3时,聚合物在30s内能快速地脱附与吸附。且当硅氧烷所占的链段摩尔分率为45以上时聚合物的涂膜性能更好。     

三七素对映异构体的计算机模拟研究

三七主要用于跌打损伤、内伤出血等内外出血症.用量子化学法,采用B3LYP方法,6-31+G(d,p)基组计算三七素对映异构体的分子结构及能量等数据,结果表明S-三七素的能量略比R-三七素高.以S-三七素为模板分子,分别选甲基丙烯酸(MAA)、三氟甲基丙烯酸(TFMAA)、丙烯酰胺(AM)、N-乙烯基吡咯烷尉(NVP)、2.乙烯基吡啶(2-VP)、4-乙烯基吡啶(4-VP)6种物质为功能单体,模拟并探讨不同功能单体对S-三七素的选择性,模拟计算分子印迹聚合的过程中,模板分子、功能单体及聚合物构型复杂,分子量大,全用PM3半经验法.采用结合能来反映S-三七素和不同单体之间的相互作用,比较模板分了与功能单体相互作用的强弱,以选择功能单体.结果证明AM的印迹效应最好而NVP最差.该模型稳定性和预测能力俱佳,从而为S-三七素的拆分及检测实验打下理论基础.     

壳聚糖结合ReO的初步理论研究

借助于密度泛函理论的B3LYYP方法,对壳聚糖及壳聚糖结合ReO的配合物（（CTS）₂-ReO,（CTS）₄-ReO）进行结合结构优化、Mulliken电荷、前沿轨道、相关能量的计算。结果表明:壳聚糖结合ReO的配合物前后,壳聚糖六元环结构基本不变,N（8）-C（4）和O（10）-C（3）键的键长有所增长;由壳聚糖结合ReO的配合物（（CTS）₂-ReO,（CTS）₄-ReO）的结合能及结合后配合物的前沿轨道能量差可推断配合物（CTS）₂-ReO和配合物（CTS）₄-ReO均可以形成,而形成配合物（CTS）4-ReO的可能性更大;配合物（CTS）2-ReO和配合物（CTS）₄-ReO形成时,壳聚糖环上的电荷发生了重新分布,电子由壳聚糖1位的羟甲基上向氨基的氮原子和Re原子移动。     

内部能量集成精馏塔技术应用于乙烯分离流程的节能研究

乙烯生产装置是石化工业中最重要的装置之一,其生产过程需要消耗大量的低温冷量,采用先进的能量集成技术优化乙烯生产过程、提高能源利用效率具有重要意义.本研究针对前脱丙烷前加氢工业乙烯装置,将内部能量集成精馏塔技术应用于乙烯分离塔,提出基于内部能量集成技术的乙烯分离流程.利用流程模拟软件Aspen Plus分别对内部能量集成精馏塔流程和开式热泵精馏流程进行严格模拟,结果表明内部能量集成精馏塔精馏段压力对新流程系统中压缩机的功耗有显著影响,最终优化的内部能量集成精馏塔精馏段操作压力为1410KPaG,提馏段操作压力为710KPaG.相对于目前先进的乙烯精馏塔开式热泵流程,内部能量集成精馏塔流程具有节能效果,内部能量集成精馏流程中系统压缩机的总功耗为38.869MW,而热泵精馏流程中系统压缩机的总功耗为39.680MW,内部能量集成精馏塔流程中系统压缩机的总功耗降低约2.04％,因此内部能量集成精馏塔具有一定的工业应用前景.     

共聚物组成的计算机估算

共聚合反应是高分子材料工业中应用最广泛的一个方法。共聚物的物理和机械性能取决于它的组成和微观结构,即单体链节在共聚物分子中的组成分布、排列顺序和链段分布对产物的性能影响较大,所以对不同单体共聚反应后的组成分析对开发新品种有很大帮助。为此,根据共聚反应中单体组成及不同单体间的共聚率与共聚物组成之间的关系,编制了对共聚物的组成进行预测和分析的程序。     

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.     

中位-四[二-(3,4-羧甲氧基)苯基]卟啉及其结合Re=O的初步研究

用密度泛函理论的B3LYP法,将中位-四[二-(3,4-羧甲氧基)苯基]卟啉及结合Re=O分子的几何构型优化,初步理论研究其前沿轨道和能量等。证明,与单独的卟吩环相比,T_(3,4)CPP的卟吩环平面性良好,环上的结构参数变化很小;Re=O与T_(3,4)CPP卟吩环的结合能明显大于与T_(3,4)CPP侧链羧基的结合能,且前者所形成配合物的稳定性显然高于后者,说明T_(3,4)CPP与~(188)Re=O结合的位点应在卟吩环上,而不在侧链羧基上。T_(3,4)CPP卟吩环结合Re=O而形成配合物的结构参数,与Vicente等Zn-卟啉衍生物的测定值相近。在卟吩环上配位时,T_(3,4)CPP卟吩环上的电荷重新分布,卟吩环碳原子的电子向4个氮原子转移:配位后,卟吩环的几何构型略收缩(0.14 A-0.19 A)和马鞍形扭转(5.7°)。     

激光辐照热效应混合模拟方法

针对激光辐照热效应模拟中传统的有限元法对复杂几何结构和多次散射光处理能力较差的问题,在三维多物理场流-固耦合问题并行计算程序CFS中实现射线追踪-有限元模拟方法.与传统有限元法相比,该方法在有限元网格划分的基础上,采用射线追踪技术将各网格单元所吸收的辐照激光能量加入方程求解系统.对2A12硬铝材料腔体结构件激光辐照热效应的计算表明,该方法提高程序对计算模型几何结构复杂性的适应能力,解决多次散射光存在时传统方法难以准确描述辐照激光能量在求解区域中分布的问题,从而有效扩展CFS程序的使用范围.     

12顶点闭合型碳硼烷异构体的结构和稳定性密度泛函理论研究

采用密度泛函理论DMol~3/DNP方法对十二顶点闭合型碳硼烷C_2B_(10)H_(12)异构体的几何结构进行优化,分析了异构体的稳定性、电荷分布以及前线分子轨道。结果表明3个异构体都有对应的稳定构型,并保持了闭式二十面体骨架结构。稳定性随着2个C原子之间距离增大而增加,即稳定性为对位间位邻位。负电荷主要集中在2个C原子上,成为主要的亲核取代反应中心。异构体具有立体芳香性,取代C原子具有对位、间位定位效应。B原子电荷密度规律,位于C原子间位的B原子负电荷密度最高,对位稍次,邻位最低。异构体分子前沿轨道和△E_(LUMO-HOMO)所预示的化学稳定性与结构能量稳定性趋势一致。     

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)

正~~     

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