The kinetics of B‐a and P‐a type copolybenzoxazine via the ring opening process

The structure of benzoxazines is similar to that of phenolic resin through thermal self‐curing of the heterocyclic ring opening reaction that neither requires catalyst nor releases any condensation byproduct. These polybenzoxazine resins have several outstanding properties such as high thermal stability and high glass transition temperature. To better understand the curing kinetics of this copolybenzoxazine thermosetting resin, dynamic and isothermal differential scanning calorimetry measurements were performed. Three models, the Kissinger method, the Flynn–Wall–Osawa method, and the Kamal method, were used to describe the curing process. Dynamic kinetic activation energies based on Kissinger and Flynn–Wall–Osawa methods are 72.11 and 84.06 KJ/mol, respectively. The Kamal method based on an autocatalytic model results in a total order of reaction between 2.66 and 3.03, depending on curing temperature. Its activation energy and Arrhenius preexponential are 50.3 KJ/mol and 7959, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 730–737, 2005     

浅析实践论视角下的马克思主义真理观

从实践论的视角分析马克思主义真理观.通过对真理的属性及其检验标准、真理和价值的关系问题的讨论,阐述了实践在马克思主义真理观中的作用和地位.     

乳胶制品生产的工序能力分析及质量控制

本文分析了乳胶制品的生产过程，并对工序能力指数进行了分析，从而推断出产品的质量。     

Aerodynamic performance analysis of trains on slope topography under crosswinds

This work used the computational fluid dynamics method combined with full-scale train tests to analyze the train aerodynamic performance on special slope topography. Results show that with the increment in the slope gradient, the aerodynamic forces and moment increase sharply. Compared with the flat ground condition, the lateral force, lift force, and overturning moment of the train on the first line increase by 153.2%, 53.4% and 124.7%, respectively, under the slope gradient of 20°. However, with the increment of the windward side's depth, the windbreak effect is improved obviously. When the depth is equal to 10 m, compared with the 0 m, the lateral force, lift force and overturning moment of the train on the first line decrease by 70.9%, 77.0% and 70.6%,respectively. Through analyzing the influence of slope parameters on the aerodynamic performance of the train, the relationships among them are established. All these will provide a basic reference for enhancing train aerodynamic performances under different slope conditions and achieve reasonable train speeds for the operation safety in different wind environments.     

Redundancy filtering and fusion verification for video copy detection

Multimedia Systems - Recently, the frame fusion based video copy detection scheme provides a possibility to detect copies in a continuous query video stream. However, its computational complexity...     

非盲图像复原综述

作为目前图像处理领域的研究重点,图像复原可移除图像中的模糊与噪声,具有重要的理论价值和广阔的应用前景。为使图像复原的研究被人们所了解,该文首先对图像复原做了简单的描述,接着介绍了近年来出现的一些非盲图像复原算法,包括基于总变分模型的算法、基于Bregman迭代的算法和基于稀疏表示的算法等,最后基于对现有算法的了解与分析,总结了图像复原研究的难点与趋势。     

下一代综合测试系统的研究与实现

LXI标准已成为测试行业的发展趋势,介绍了LXI技术的起源、分类及发展。重点介绍了IVI驱动程序的构成、特点,并基于IVI驱动程序,利用LabVIEW实现了一个话路测试仪,经过测试表明此仪器符合LXI仪器标准,且具有成本低、通用性强等诸多特点。