炭/炭复合材料用高性能浸渍剂沥青的研究

根据原生QI杂质由微米级炭粒构成的特性,采用溶剂絮凝法对煤焦油进行了净化处理,以净化煤焦油为原料制备了低QI含量的高性能浸渍剂沥青,对比研究了高性能浸渍剂沥青的流变性能和渗透性能。结果证实:高性能浸渍剂沥青极大地改善了浸渍效果,并且使炭/炭复合材料的力学性能显著提高。     

浸渍剂沥青QI测定的研究

在分析国内外浸渍剂沥青QI测定标准的基础上，对比研究了中国煤沥青QI测试标准对浸渍剂沥青QI测定的适用性，结果发现中国测试标准存在很多问题，分析了造成这些差异的原因，并对制定中国浸渍剂沥青QI测试标准提出了建议。     

石油沥青合成低软化点、高残炭沥青树脂

两种石油沥青在低温下合成沥青树脂，考察了工艺参数和原料组成对沥青树脂性能的影响。结果表明，大庆石油沥青反应活性适中、含胶质—沥青质较少，可以合成具有软化点(SP)为80～112C、残炭(CY)为59．13％、β树脂(TI～PS)含量为21．19％、喹啉不溶物(QI)值为1．32％、灰分为0．02％的优质沥青树脂，该沥青树脂已能够满足作为浸渍剂的要求。     

沥青基C／C复合材料氧化性能影响因素分析

综述了影响沥青基C／C复合材料氧化性能的一些宏观和微观因素及交互作用。分析表明：沥青浸渍剂的组分与性能及热处理温度影响沥青基C／C复合材料的宏观结构和微观结构,使复合材料具有不同的抗氧化性能;不同类型与织构的纤维其抗氧化性能也不相同,亦影响C／C复合材料抗氧化性能。     

Compensation of quadrature imbalance in an optical coherent OQPSK receiver in presence of frequency offset

In this paper,we describe the impact of quadrature imbalance (QI) in the presence of frequency offset in an optical coherent offset quadrature phase shift keying (OQPSK) receiver.Arbitrary conjugate misalignment was realized in a 2×4 90° optical hybrid,and the ellipse correction (EC) method of quadrature imbalance was applied in our simulation.In the case of transmission,the EC method can significantly improve the system performance.     

Structures of insoluble carbon in tars and pitches

Primary or True QIs, and also the so-called ‘dirt’ were separated from seven tar sources available in Canada from four different steel companies, by filtering hot tar solution of quinoline and other good solvents. After washing with quinoline and acetone and drying, the filter cake was examined under scanning electron microscope (SEM) and analysed for inorganic impurities by wave length and energy dispersive X-ray spectrometers. A limited amount of work was carried out on a production pitch blend, utilizing optical microscopy. After the filtration process, the filtrates which represented the QI free tars were subjected to distillation at atmospheric pressure and various pitches were prepared with a softening point range of 70–100°C. The pitches were dissolved in quinoline and analysed for QIs. The small amount of QI from each pitch was extracted and dispersed with solvent onto a microscope slide. The samples then were subjected to SEM and in one case to optical microscope studies; the sizes and shapes of the QIs were determined and compared with the QIs originally found in the individual tars. Photographs have been taken during the scanning work to record findings which have been considered typical and demonstrative of the findings. In order to gather further information on the role of QI in tars and pitches, particle size distribution was determined of QI extracted from a tar and a production pitch by a Coulter Counter.     

在计算机围棋中形象思维的研究

在计算机围棋中形象思维的研究王鲁明戴汝为（中科院自动化所人工智能实验室北京１０００８０）关键词人工智能,计算机围棋,形象思维,神经网络１）自然科学基金资助项目．收稿日期１９９５－０６－０１１引言目前,对于计算机围棋,无论是基于博弈论的方法,还是基于传...     

基于BP神经网络的西安环境空气质量的预测

针对目前空气质量污染日益严重的问题,提出了一种基于神经网络的环境空气质量的预测方法.借助于Matlab分别建立空气污染指数（API）和环境空气质量指数（AQI）对空气质量影响的数学模型.利用Matlab对各污染物浓度数据进行分析,计算相应的空气污染指数（API）和环境空气质量指数（AQI）,对结果进行对比.运用BP人工神经网络的多层神经网络对全市大气污染物浓度的实测值进行训练学习,建立模型.同时结合未来一周西安市天气预报,用此模型对污染物浓度进行预测和预报,以达到对大气环境质量进行预测预警的作用.应用实例表明：人工神经网络应用于大气环境质量预测预警是比较理想的.     

基于无线充电QI标准的2FSK解调设计

分析了无线充电QI标准中2FSK信号的调制模式、载波频率等方面的特点。针对该种信号,提出并实现了一种2FSK信号数字解调的新方法。该方法抛弃信号频率本身的特征,而通过多周期信号的测量宽度之和的变化来反映频率的变化。首先通过一固定频率对输入信号周期宽度进行测量并求和,然后将该和值进行去直流、平滑等处理,从而提取其中的频率变化特征以便于后期解码处理。在最终的FPGA实现中,该方法可以通过2 MHz的频率检测出周期相差32 ns的两种信号的频率变化情况。