Dynamics of novel hydrogen-bonded acidic fluorinated poly(amide-imide-silica) hybrids studied by solid-state NMR

Novel hydrogen-bonded acidic fluorinated poly(amide-imide-silica) hybrid materials, FPAI-SiO₂ (6E and 6F) series, were synthesized by a sol-gel process. The structures and spin relaxation of the hybrids were characterized by infrared (IR), and ²⁹Si and ¹³C nuclear magnetic resonance (NMR) spectroscopy. The abundant Q⁴ structures implied that in free catalyst the degree of condensation of tetramethoxysilane was enhanced by hydrogen-bonded acidic fluorinated poly(amide-imide). The dynamics on the local mobility of the hybrids was investigated by the time constant for energy exchange between ¹H and ²⁹Si spin system (T_SiH) and spin-diffusion path length (L) measurements. It was found that the faster T_SiH of 6E and 6F hybrids compared with the previous study of similar 6C and 6D hybrids implied that 6E and 6F hybrids had more aggregated structures even though the organic terminal segment changed from rigid imide to more flexible amide. The interactions of the charge transfer between donor and acceptor molecules or π-π aromatic stacking may be the dominant factors to affect the structures of 6E and 6F hybrids. Moreover, M¹ and D² segments of 6F hybrids had the same level mobility and the mobility of the 6F hybrids was little improved as the soft and flexible 1,3-bis(3-aminopropyl)-tetramethyl-disiloxane segment was incorporated in the dense structures of 6F hybrids. All of the L values of 6E and 6F hybrids were on the scale of 3.5-4.0 nm. The result also suggested that 6E and 6F hybrids had similar denser structures as 6D hybrids.     

Semantic Transparency,Brain Monitoring and Evaluation of Hybrid Cognitive Architectures

In constructing hybrid systems, there is a need for a principled basis to determine the relative roles or functions of artificial neural network and symbolic approaches. The primary objective of the work to be reported is the construction of a conceptual and methodological framework that permits an iterative sequence in which a hybrid model predicts the basis of cognitive performance and an objective analysis of performance provides empirical data, evaluating (and thus constraining) the structure and processes of the model. In seeking a linkage between a hybrid model of cognition and human performance the concept of “semantic transparency” has been adopted, since it can be used in analyzing and describing both the chracteristics of a model of cognition and the processes underlying human performance. An overview of a specific, ”strong” hybrid architecture is presented. The characteristics of the virtual machines which compose it and the nature of their interaction are illustrated. An approach to the questions of evaluation is described based on empirical data obtained by brain monitoring of subjects during cognitive performance.     

我国有线电视事业的现状和发展

本文详细系统地介绍了我国有线是视发展历史和现状，及其经营和管理方法。重点介绍了北美的ＣＡＴＶ技术发展动向。最后，指出我国ＣＡＴＶ事业发展中的应用重视的问题。     

New accurate two-noded shear-flexible curved beam elements

 There are two purposes of this work. One is to present two accurate two-noded finite elements which are derived from the potential energy principle and the Hellinger–Reissner functional principle respectively. The second is to show the successful application of the internal displacement parameters in developing a high-order related displacement-rotation interpolation field. Because the derived interpolation field is capable of accurately modeling deformation modes in extreme thin curved beams and nearly straight beams, both shear locking and membrane shocking are avoided. Several standard numerical tests display superior behaviors of the present elements. Received: 5 February 2002 / Accepted: 16 September 2002     

ADSS光缆的力学计算

介绍了ADSS光缆的力学计算，给出了光缆弧垂、张力、应变和悬长等计算公式，并对普遍采用的“悬链线”和“抛物线”两种计算方法加以比较。     

我国有线电视的网络媒体价值

阐述有线电视网络媒体的特点，有线电视网络媒体面临的困境及解决办法，最后展望有线电视网络媒体价值。     

ATH在无卤阻燃聚乙烯电缆料中的应用研究

以EVA改性LDPE,以偶联剂改性ATH,通过一系列配方的研究和性能测定,认为可以设计出适合于电缆料用的无卤阻燃聚乙烯的配方。     

求解电缆自感系数的一个佯谬

用求自感系数的两个常用公式求解实心电缆自感系数时，如果不注意对公式中Φm及I的正确理解，将会得到不一致的“佯谬”结果。本文通过将实心电缆等效为许多细线圈的方法，用2种公式求解得到了一致的结果。     

玻璃钢缓弯弯头模具的设计和制作

本文详细叙述了φ２００×９０°玻璃钢弯头模具的设计和制作方法。     

Development of cable fault location method using fiber optic distributed temperature sensor

When ground-fault problems occur on a cable line, immediate fault location and restoration are required. Therefore, various new methods to locate the fault point instantaneously have been investigated to replace such conventional methods as the Murray loop method and the pulse radar method [1]. These methods require a long time to locate the fault point. One possible fault location method is to sense the temperature rise following a ground fault using a fiber optic distributed temperature sensor. Application of this method was found feasible through sensing the temperature rise at a ground-fault test using a thermocouple as a temperature sensor with test cables [4]. A power/optical composite cable was prepared experimentally and after verifying its thermal mechanical performance, the temperature rise at an incidence of a fault was determined and the anticipated performance was demonstrated in a ground-fault test. This article describes the outline of the test.