Preparation of BaTiO3-Based Nonreducible X7R Dielectric Materials Via Nanometer Powders Doping

Nonreducible X7R dielectric materials, which can be cofired with Ni electrode, were obtained by doping nanometer additives to BaTiO₃ powders synthesized by employing a sol-gel method. The crystallization process, structure and constituent of nanometer additives, as well as morphologies were studied via differential thermal and thermogravimetric analyses (DTA/TG), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of the calcining temperature of dopants on the dielectric properties were also discussed. The experiment results proved that higher-performance X7R dielectric materials could be obtained via nanometer doping compared with conventional doping. At room temperature, dielectric constant is more than 3000; dielectric loss lower than 1.0% and insulation resistance more than 10¹¹Ω ⋅cm.     

Machinability of Metal Matrix Composites Reinforced by 3-D Network Structure

Metal matrix composites reinforced by three-dimensional (3-D) continuous network structure reinforcement (3DCNRMMC) are difficult to machine due to serious tool wear and poor surface roughness caused by the brittle and hard reinforcement which interpenetrate into ductile matrix. In order to achieve the approach of low cost of 3DCNRMMC, the machinability of it needs to be understood. The influences of three cutting parameters and volume fraction of reinforcement on cutting force were analyzed in detail. The results indicate that: (1) Due to the brittle phase(s) introduced into ductile matrix of composites, there is a large fluctuation of cutting force causing deterioration of machinability. The fluctuation ranges of cutting forces, initially increase rapidly with the increase of volume fraction of reinforcement and then decrease finally, are largest at the range of the volume fraction of 55–65%; (2) The influence of cutting parameters on cutting force is obvious. With the increases of cutting speed, cutting force decreases gradually unless cutting speed exceeds the value of 209 m/min. Cutting forces increase with increasing feed rate and depth of cut; (3) Owing to the large fluctuation of cutting force, there were some cratered surfaces caused by Si₃N₄ reinforcement pulling-out and flaking-off. Some brittle phase protruding from the machined surface caused the deterioration of machined surface.     

超细片状铝粉和铝银浆的制备

超细鳞片状铝粉和铝银浆由于其特殊的二维平面结构，具有良好的遮盖力、显著的屏蔽效应、光学反射能力；超细鳞片状铝粉和铝银浆颜料的制备方法很多，本文采用机械化学法制备超细鳞片状铝粉和铝银浆。     

Improvement in the volume efficiency of multilayered ceramic capacitors (MLCCs)

An attempt was made to improve the conventional lamination process in the multilayered ceramic capacitors (MLCCs) fabrication by adapting a solvent treatment on the BaTiO₃ green sheets. During the lamination process, additional particle rearrangement in the BaTiO₃ green block was stimulated by solvent treatment. This rearrangement resulted in a more compact structure of the BaTiO₃ green sheets compared to that obtained through the conventional lamination process. The overall thickness of BaTiO₃/Ni/BaTiO₃ laminates was also reduced after solvent treatment. It is suggested that miniaturization in the fabrication of MLCCs can be improved by adapting a solvent treatment during the lamination process.     

多元回归分析在电热式平板硫化机热板温度场中的应用

分析电热平板硫化机热板温差大的主要影响因素,重点研究热源分布情况对温差的影响.以400×400电热平板硫化机为例,应用多元回归的二次响应曲面模型及其子模型,对热源间距(电热管间距)与热板表面最大温差之间的函数关系进行预测,检验并分析预测结果(拟合曲线)的可靠程度,从而得出较合理的数学模型,即完整二次响应曲面模型.此模型可为工程设计提供参考依据.     

A 3-GHz 70-mb SRAM in 65-nm CMOS technology with integrated column-based dynamic power supply

Column-based dynamic power supply has been integrated into a high-frequency 70-Mb SRAM design that is fabricated on a high-performance 65-nm CMOS technology. The fully synchronized design achieves a 3-GHz operating frequency at 1.1-V power supply. The power supply at SRAM cell array is dynamically switched between two different voltage levels during READ and WRITE operations. Silicon measurement has proven this method to be effective in achieving both good cell READ and WRITE margins, while lowering the overall SRAM leakage power consumption.     

基于C8051f020的标准电源控制单元的设计及实现

介绍了基于C8051f020的程控标准电源的控制部分。该控制单元以C8051f020为核心实现了PID控制器及人机交互的设计,并给出了具体实现方法,同时在实际电路的调试中收到了良好的效果。     

加强企业统计工作的思考

企业统计是生产经营成果化、数量化的数字表现，是经济社会各项主要统计指标的源头数据之一。因此强化企业统计，加快统计信息网络建设，提高综合统计人员的素质，对企业的经营、对政府的宏观调控有着重要意义。     

浅淡高校校办产业的现状与发展

我国高校校办产业发展到今天,已有十几年的历史了,在这十几年里,高校产业利用自身的人才、技术、信息等优势,形成了科技成果转让的良性循环,它为学校的发展起到了相当重要的作用.特别是科技产业,以高新技术为依托,以市场为导向,实现教学、科研、生产相结合的模式,具有较强的竞争发展能力.有的企业已形成了一定规模,所生产的高科技产品在市场上具有一定的竞争能力.从目前看,高校科技产业在我国知识经济发展中,已经开始占据着越来越重要的地位.从学校的建设上看,科技产业是教育改革的产物,它的产生不仅给学校带来了直接的经济效益,更重要的是增强了学校的实力,加速了学科建设,提高了高校的学术科研水平,应该说,学校科技产业的发展对整个教育的发展起着不可忽视的作用.但在发展的同时,也相继出现了一些需要解决的问题,只有正确解决这些问题,高校企业才能健康有序的发展,才能创造出更大的社会效益和经济效益.     

安钢高线品种开发的优势与实践

介绍了安钢高线的技术装备、工艺转化及创新，以及自投产以来的产品结构调整和重点产品的开发情况。