柴油降凝剂的发展现状及其研究热点

综述了梳状聚合物型、烯-不饱和酯聚合物型、酰胺酸盐共聚物型、烷基芳烃型和聚丙烯酸高碳醇酯型等几种柴油降凝剂近年来在合成方面的研究进展,重点讨论了目前的研究热点,展望了其今后的发展方向。     

丁基橡胶压敏胶粘带的制备及其性能研究

以丁基橡胶为主要原料研制出了丁基橡胶压敏胶粘带,讨论了丁基橡胶、增黏剂、增塑剂和填料用量等对胶粘带性能的影响,研究了其对三元乙丙橡胶防水卷材接缝的粘结作用。     

Control of a DC/DC converter by fuzzy controller for a solar pumping system

The exploitation of the solar energy is very significant for the very sunny countries. Moreover the dryness phenomenon in these country is imposes more and more the use of pumping plants. The storage of the water in insulated basins from the wells has a double advantage. On the one hand, it is a technical storage solution of the solar energy collected by the photovoltaic panels. On the other hand, it is a hygienic way out to supply water for the rural population.In our work, we propose a technique for the identification of the maximum power point (MPP) based on fuzzy logic. This method is used to generate the cyclic ratio to operate the switcher within the maximum power of a photovoltaic array (PVA).For simulation purpose we made a complete modeling of the entire system. The system carried out consists of a photovoltaic array supplying, through a DC converter, a direct current (DC) engine coupled to a centrifugal pump. Our experimental bench consists of two principal units. A DC converter module composed of IGBT power transistors. And a processing module connected to a PC serial port, handling the input signals delivered by photovoltaic generator and controlling the power unit.The obtained experimental results confirm the simulation result which is very satisfactory and show the utility of the fuzzy controller for the optimization of the system.     

New ISFET interface circuit design with temperature compensation

An integrated and new interface circuit with temperature compensation has been developed to enhance the ISFET readout circuit stability. The bridge-type floating source circuit suitable for sensor array processing has been proposed to maintain reliable constant drain-source voltage and constant drain current (CVCC) conditions for measuring the threshold voltage variation of ISFET due to the corresponding hydrogen ion concentration in the buffer solution. The proposed circuitry applied to Si₃N₄ and Al₂O₃-gate ISFETs demonstrate a variation of the drain current less than 0.1 μA and drain-source voltage less than 1 mV for the buffer solutions with the pH value changed from 2 to 12. In addition, the scaling circuitry with the V_T temperature correction unit (extractor) and LABVIEW software are used to compensate the ISFET thermal characteristics. Experimental results show that the temperature dependence of the Si₃N₄-gate ISFET sensor improved from 8 mV/°C to less than 0.8 mV/°C.     

固定延迟的流水线双精度浮点除法电路

除运算采用泰勒级数展开,用5级流水线结构,查找表大小缩小为2.5kB,并获得固定延迟.FPGA综合结果表明,与其他设计电路相比,面积减小了33%.     

数字电视用高压开关电源设计

描述一种用于数字彩电的小功率高压开关电源的基本工作原理及设计要点。该开关电源采用了高压发生电路与行扫描电路相分离的独立结构。独立振荡器产生的开关信号提供给开关管,推动高压变压器输出CRT管所需的阳极高压,并通过对阳极高压取样,控制振荡信号频率,以达到稳定高压的目的,彻底解决了大屏幕显像管所需的阳极高压及其稳定性问题。采用独立高压供电方案,行扫描电路的设计和调整得以简化,也使行扫描输出电路负载过重问题得到较好的解决。     

Predicting the properties of petroleum blends

The aim of this study was to find new correlations to predict the properties of petroleum fractions blends. Several correlations for viscosity, smoke point, freezing point, Reid vapor pressure, aniline point, and cloud point were developed. These new correlations were assessed for their ability to predict the properties by comparing the estimated values with the experimental data as well as other correlations in literature. The developed correlations gave an absolute average deviation of 2.6 mm²/s for viscosity, 0.015 mm for smoke point, 0.05 K for freezing point, 6.47 kPa for RVP, 0.32 K for aniline point, and 0.9 K for cloud point.     

国内原油降凝剂研究概况

介绍了目前我国原油降凝剂应用现状、研究成果和应用的种类,综述了降凝剂的工作机理,并对今后研究提出了建议:加强降凝剂机理研究,开发适用范围更大的新型降凝剂,研究低温降凝剂,降凝剂研究应与输油工艺紧结合等。     

基于统计特征的二维矢量地图鲁棒水印算法

数字矢量地图的实际应用受到数据安全性的限制，数字水印技术是解决该问题的重要辅助手段．在二维矢量地图数据中嵌入水印需要充分考虑地图数据及其应用环境的特殊性．现有算法所暴露的一个共同的缺陷是水印的嵌入会破坏原始数据的形状特征．本文提出了一种基于数据统计特征的鲁棒水印算法，该算法以地图曲线特征点提取为基础，水印的嵌入能够尽量保持曲线本身的形状特征．实验表明该水印方案具有较好的隐蔽性和鲁棒性，能够抵抗地图几何变换、数据简化、插值，以及小幅度的加性噪声．