CnSi(n=49,50)的理论研究

用量子化学从头算方法研究了C     

Numerical simulation of filler metal droplets spreading in laser brazing

A finite element model was constructed using a commercial software Fidap to analyze the Cu-base filler metal droplet spreading process in laser brazing,in which the temperature distribution,droplet geometry, and fluid flow velocity were calculated.Marangoni and buoyancy convection and gravity force were considered,and the effects of laser power and spot size on the spreading process were evaluated.Special attention was focused on the free surface of the droplet,which determines the profile of the brazing spot. The simulated results indicate that surface tension is the dominant flow driving force and laser spot size determines the droplet spreading domain.     

聚氧乙烯功能基复合修饰聚氨酯的合成 及其血液相容性研究(Ⅰ)

通过十八烷基聚氧乙烯和环氧氯丙烷的封端反应制备了α-环氧基-ω-十八烷基聚氧乙烯大单体.并采用BF     

三维超音进气道内外流场的数值模拟

用区域分裂有限体积法求解了三维Ｅｕｌｅｒ方程和Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程。空间方向采用Ｒｏｅ平均算法，时间方向采用Ｒｕｎｇｅ－Ｋｕｔｔａ方法。对某飞航导弹的全弹身－进气道流场和某型号战斗机进气道内外流场进行了计算，得出了满意的结果。     

聚芳醚酮单体结构与反应活性的研究

利用从头算ＲＨＦ方法研究了聚芳醚酮单体４，４’－对苯二酚、４，４’－联苯二酚及４，４’－二氟苯酮。结果表明，它们的苯环皆存在一定的扭转，首次给出联苯二酚全优化结构，其苯环二面角为５１．８°，活性稍强于对苯二酚，但引入更多的链支化活特点，含联苯基聚芳醚醚酮的链支化比不含联苯基的ＰＥＥＫ严重，故前者结晶性差，反应机理及实验还表明：前者凝胶化的浓硫酸溶液中存在一种羰基被极化后的红色阴离子。     

Heterogeneous integration of InP HEMTs on quartz wafer using BCB bonding technology

Heterogeneous integrated InP high electron mobility transistors(HEMTs)on quartz wafers are fabricated successfully by using a reverse-grown InP epitaxial structure and benzocyclobutene(BCB)bonding technology.The channel of the new device is In_0.7Ga_0.3As,and the gate length is 100 nm.A maximum extrinsic transconductance gm,max of 855.5 mS/mm and a maximum drain current of 536.5 mA/mm are obtained.The current gain cutoff frequency is as high as 262 GHz and the maximum oscillation frequency reaches 288 GHz.In addition,a small signal equivalent circuit model of heterogeneous integration of InP HEMTs on quartz wafer is built to characterize device performance.     

基于下变频和IQ解调的外差型相位敏感光时域反射技术的模式识别EI北大核心CSCD

基于模拟下变频器、数字IQ解调和反向传播(BP)神经网络,采用现场可编程门阵列结合数字信号处理器(FPGA+DSP)的数据采集和处理架构,提出了一种全嵌入式高信噪比(SNR)、高分辨率和低成本的外差型相位敏感光时域反射(Φ-OTDR)技术模式识别方法。针对外差型Φ-OTDR技术,使用DSP、FPGA及其外围硬件电路替代原有的GHz级高速采集卡和信号发生器,减小了系统的体积和成本。在此基础上,设计了基于时空域二维图提取形态学特征的方法,并采用BP神经网络进行分类识别;所提方法相对于传统的针对一维信号进行模式识别的方法误报率更低、识别率更高。实验结果表明,所设计的基于FPGA+DSP全嵌入式并行信号处理架构满足实时监测的要求,SNR高达12.43dB,事件识别准确率达到97.78%。     

Properties of Seamless W Sub-Micro Electrode Used for Phase Change Memory

In order to improve the reliability of C-RAM devices, a seamless sub-micro W heating electrode in diameter 260 nm is fabricated with standard 0.18 μm CMOS processing line. Then we successfully manufacture a chalcogenide random access memory device using this seamless sub-micro W heating electrode. The results show good electrical performance, e.g. the reset current of 1.3mA and the set/reset cycle up to 10^9 have been achieved.     

吗啡和海洛因等生物碱的高效液相色谱化学发光测定

研究了吗啡、可待因、Ｏ＾３单乙酰吗啡和海洛因等生物碱在多聚磷酸介质中与高锰酸钾的发光行为和光谱现象。建立了反相 高效液相色谱化学发光检测吸毒者尿液和雅片中吗啡、可待因等物质的方法。     

In0.49Ga0.51P中缺陷的俘获行为

利用深能级瞬态谱（ＤＬＴＳ）和瞬态光电阻率谱（ＴＰＲＳ）研究了利用金属有机物化学汽相沉淀（ＭＯＣＶＤ）生长的未有意掺杂的Ｉｎ０．４９Ｇａ０．５１Ｐ中缺陷对载流子的俘获过程和发射过程．利用ＤＬＴＳ测量观测到了一个激活能为０．３７ｅＶ的缺陷,该缺陷的俘获势垒值介于１８０ｍｅＶ到２４０ｍｅＶ之间．该缺陷的俘获势垒值的大的分布被解释为缺陷周围原子重组的微观波动．在研究中发现研究这些缺陷的俘获过程比发射过程更有效,俘获势垒为０．０６ｅＶ和０．４０ｅＶ的两个缺陷在俘获过程中被观测到,而在发射过程中并没有观测到