A high-current and high-temperature 6H-SiC thyristor

A 6H-SiC thyristor has been fabricated and characterized. A forward breakover voltage close to 100 V and a pulse switched current density of 5200 A/cm² have been demonstrated. The thyristor is shown to operate under pulse gate triggering for turn-on and turn-off, with a rise time of 43 ns and a fall time of less than 100 ns. The forward breakover voltage is found to decrease by only 4% when the operating temperature is increased from room temperature to 300°C. It is found that anode ohmic contact resistance dominates the device forward drop at high current densities     

各种状态的液体通过核孔膜的规律

介绍了液体通过核孔膜规律方面取得的新认识，包括：（１）纯净液体通过核孔膜的规律；（２）核孔膜测定液体粘滞系数的各种方法；（３）各种物质溶液浓度的核孔膜测定；（４）液相混合物快速分离和化学分离；（５）流体中固体微粒对核孔膜的堵塞及其公式；（６）用核孔膜滤除液中各各斩规律。     

The effects of plasma etching induced gate oxide degradation onMOSFET's 1/f noise

The effects of the plasma etching process induced gate oxide damages on device's low frequency noise behavior are investigated on MOSFET's fabricated with different field plate perimeter to gate area ratio antennas. Abnormal 1/f noise spectrum with a shoulder centered in the frequency range of 100 and to 1 kHz was frequently observed in small geometry devices, and it is attributable to a nonuniform distribution of oxide traps induced by plasma etching process     

层状催化剂颗粒的优化设计——双组分等温平行反应体系

针对双组分等温平行反应体系,分析讨论了以提高催化剂活性和选择性为目标时催化剂活性组分的最优分布形式(为δ-函数分布),并给出了确定这种反应体系的催化剂的最佳活性层位置的计算方法。结果表明:以提高选择性为目标的最佳活性层位置比以提高活性为目标的要更靠近催化剂核心,实用的最优位置应介于二者之间。最后,本文还研究了反应动力学级数、本性选择性以及内扩散模数(Thiele 模数)等因素对最佳活性层位置的影响。     

火电机组运行优化系统的现状与展望

简单回顾了国内外在火电机组运行优化领域的研究历程，列举了目前国内外市场上针对火电机组的各种主流运行优化产品的功能特点和应用情况，分析了国外引进产品和国内自主研发产品在中国当前市场环境下各自的优势和劣势。介绍了当前运行优化系统在国内电站机组的应用现状，阐述了国内外运行优化系统在实际应用中存在的问题，并提出了相应的改进意见。对机组运行优化系统的未来发展进行了展望，指出机组运行优化系统将利用先进技术设备和信息平台，与电站管理紧密结合，在日益规范的市场中不断发展完善，为提高电站经济性发挥更大的作用。     

Orientation in uniaxially stretched plasticized atactic polystyrene

Summary Fourier transform infrared spectroscopy and birefringence measurements have been used to study the changes in molecular orientation which occur on drawing of plasticized as compared to pure polystyrene (PS) at a temperature T=Tg+Cte. No influence of plasticizers on orientation can be detected whatever the interactions between small molecules and PS chains are. Comparison with previous results obtained on PS-poly(vinylmethyl ether) compatible blends confirms the importance of the macromolecular nature of the second component to enhance the friction coefficient leading to higher level of chain orientation.     

机械化水稻直播栽培技术

水稻机械化直播栽培技术是指在水稻栽培过程中省去秧田育秧和拔秧移栽作业流程,通过直播机,将催好芽的谷种直接播在大田里,进行培育管理的技术.与传统移栽稻相比,具有省力、省工、省本、省秧田、提高生产率、减轻劳动强度等优点.