Effect of structure on the properties of polyurethanes based on aromatic cardanol-based polyols prepared by thiol-ene coupling

Industrial-grade cardanol and 2-mercaptoethanol were reacted to generate hydroxyl-functionalized cardanol by UV, free-radical-initiated thiol-ene coupling between the double bond moieties of the cardanol long carbon side chain and thiol functional groups. The average hydroxyl number of the hydroxyl-functionalized cardanol was controlled by reaction time, with the hydroxyl values of this ranging within 168–201 mg KOH g⁻¹. This cardanol was then used as a polyol to prepare cardanol-based polyurethane with hexamethylene diisocyanate and a NCO/OH ratio of 1. To compare the effect of cardanol-based polyols with the properties of cardanol-based polyurethane, cardanol modified with 10-undecylenate was used as a raw material to prepare cardanol-based polyols, including the long carbon chain of 10-undecylenate. All properties were examined, and data revealed that cardanol-based polyols including this long carbon chain can improve the hydrophobic and mechanic properties of the cardanol-based polyurethane.     

Application of finite-part integrals to three-dimensional fracture problems for piezoelectric media Part I: Hypersingular integral equation and theoretical analysis

This paper deals with some basic linear elastic fracture problems for an arbitrary-shaped planar crack in a three-dimensional infinite transversely isotropic piezoelectric media. The finite-part integral concept is used to derive hypersingular integral equations for the crack from the point force and charge solutions with distinct eigenvalues s _i(i=1,2,3) of an infinite transversely isotropic piezoelectric media. Investigations on the singularities and the singular stress fields and electric displacement fields in the vicinity of the crack are made by the dominant-part analysis of the two-dimensional integrals. Thereafter the stress and electric displacement intensity factor K-fields and the energy release rate G are exactly obtained by using the definitions of stress and electric displacement intensity factors and the principle of virtual work, respectively. The hypersingular integral equations under axially symmetric mechanical and electric loadings are solved analytically for the case of a penny-shaped crack.     

一种发出红色荧光的六核配合物[Cu6（pymt）6]

合成了一价铜和2-巯基嘧啶盐的配合物[Cu6（pymt）6]并进行结构分析，该配合物能发出强的红色荧光。其中，一价铜离子的配位环境为变形平面三角形，陪体pymt采用μ3-S2N桥联方式参与配位。     

Moving beyond the fourth dimension with an IFC-based single project database

4D CAD has been an active research area for many years. The first generation 4D tools simulated construction schedules and demonstrated the potential benefits in several case studies. Researchers tried to improve the functionality of the first generation 4D tools by adding annotations and highlighting the building elements that have problems. The future generation 4D tools are expected to include more than these. It has been envisioned that 4D models would be part of project databases in order to take decisions related with different project dimensions.This paper presents the development and implementation of a new 4D planning tool which is a part of a product model-based project database. This tool brings the 4D simulation and cost estimation together and aims to contribute to what-if analysis in construction projects. The last part of the paper presents a case study in which the proposed prototype is evaluated.     

BCM7113基本交互型STB的硬件设计

介绍一种基于BCM7113的数字电视机顶盒的硬件设计方案，该方案是应杭州市场的需求而设计开发的，最大的特点就是有线电视网和以太网的结合，BCM7113是Broadcom公司出品的集系统控制、信道解码和标清MPEG-2解码于一体的数字电视机顶盒专用芯片，该平台具有强大的扩展接口，如USB、ITU—R656等，并扩展了10M／100M以太网接口，有很强的可升级性。     

基于VBA技术的Word自动判卷系统的实现

介绍一种用VBA技术实现对Word文档操作的自动判卷系统。学生答题完后计算机可自动批阅并显示分数和正确解,根据得分情况给出相应的学习建议。该系统具有较高的判卷准确性,可以成为学习者平时练习和模拟考试的辅助工具。     

基于极限学习机的堤防工程多元风险指标评价方法

为提高堤防工程风险评价的准确性,提出了基于极限学习机的堤防工程多元风险指标评价方法。首先,综合考虑影响堤防风险的28个评价指标,利用层次分析法从预警系统、堤防工程系统、环境系统和社会经济系统这4个方面建立了堤防工程多元风险评价指标体系。接着,基于极限学习机算法对28个指标进行标准化处理及分级标准构建,以风险指标作为输入量,分级隶属度作为输出量,划分风险等级,量化评价指标,估计多元风险评价指标值和判断风险的严重程度。最后,依托鄱阳湖重点堤防——康山大堤,构建多元风险评价指标体系,运用极限学习机算法计算多元风险评价指标值。评价结果表明:康山大堤目前处于基本安全水平,符合康山大堤经过两次加固后的工程实际情况,并与其他方法进行对比,验证了提出方法的可靠性和有效性。该方法可拓展应用到其他重要水工结构工程风险评估中。     

网络控制系统优化设计研究

研究网络控制系统的优化问题,提高系统的实时性。针对传统的网络控制系统是闭环系统,网络带宽有限,网络传输中的时间延迟、数据包丢失等问题不可避免。当发生以上情况时,反馈信号不能及时传回,造成控制信号发出延迟,影响了系统的实时性。为了解决上述问题,提出了一种非规律时滞补偿算法,把时滞信号引入自由权矩阵,能够得到延迟信号相关稳定性条件,并充分运用线性信号特征矩阵保证网络控制系统的性能,保证系统在线控制的实时性。证明改进方法能够避免控制信号延迟造成的滞后问题,提高了网络控制系统的实时性。     

计及风电置信风险的源网协调多目标优化调度

为了更为合理灵活地评估风电高估/低估给电力系统优化调度带来的风险性以及降低调度决策的保守性,基于风电机会约束提出风电高估/低估置信风险功率偏差量化计算方法,并在决策变量中引入变压器变比调节和无功补偿容量优化,构建计及风电置信风险和源网协调运行的经济/风险多目标优化调度模型。提出一种基于可行性和非劣性综合排序回溯搜索算法,从而实现对调度模型的高效准确求解。IEEE 30节点系统算例结果验证了所提方法的有效性和优越性。