煤焦油热解制备中间相炭微球

含有３．７％吡啶不溶物的煤焦油和经热过滤去除吡啶不溶物的净化焦油在自升压下聚合，产物经热过去除母兴，滤饼用吡啶抽提至无色得中间相炭微球，在偏光显微镜下观察聚合产物的结构，在扫描电镜下观察中间相炭微球的形貌。结果表明，由于聚合产物的粘度较低，所产生的ＭＣＭＢ易于从母液中分离出来；原料中的吡啶不溶物有利于阻止ＭＣＭＢ的融并，在一定程度上可起到控制球径的作用；对无吡啶不溶物煤焦油高温短时间聚合后骤冷有利     

GaAs／GaAlAs中红外量子阱探测器和双色量子阱红外探测器

本文报道我们在国内率先研制的ＧａＡｓ／ＧａＡｌＡｓ中红外（３～５μｍ）量子阱探测器和双色量子阱红外探测器的制备和性能．ＧａＡｓ／ＧａＡｌＡｓ中红外量子阱探测器是光伏型，探测峰值波长为５．３μｍ，８５Ｋ下的５００Ｋ黑体探测率为３e９ｃｍ·Ｈｚ１／２／Ｗ，峰值探测率达到５×１０１１ｃｍ·Ｈｚ１／２／Ｗ，阻抗为５０ＭΩ．ＧａＡｓ／ＧａＡｌＡｓ双色量子阱红外探测器是偏压控制型的两端器件，在零偏压下该探测器仅在３～５μｍ波段有响应，响应峰值波长为５．３μｍ，８５Ｋ温度下５００Ｋ黑体探测率为３e９ｃｍ     

化学汽相沉积掺砷多晶硅膜初探

分别用AsH_3、SiH_4和Ar作源气和携带气体,在常规的水平高频加热汽相沉积系统中沉积了掺砷多晶硅膜。研究了影响膜的沉积速率及电阻率的诸因素。并与国外报导的同类工作作了比较。发现:一、掺砷多晶硅膜的电阻率与气相中[As)/[Si]的关系中确实存在有一最小值。即随着气相中[As]/[Si]的不断增加,多晶硅膜的电阻率下降,但到某一值后,反而会随着气相中的[As]/[Si]增加而增加。二、除气相中的[As]/[Si]、晶粒大小等影响掺砷多晶硅膜的电阻率以外,气体中的含水量对沉积后掺砷多晶硅膜的电阻率影响颇大。三、俄歇能谱分析发现高掺砷多晶硅膜中的氧含量和砷含量相当。认为该现象的出现和沉积时气相中AsH_3的存在有关。并可能是目前不易制得低电阻率(≤10~(-3)Ωcm)掺砷多晶硅膜的原因。     

SiO_2、PSG膜在HF-PO_4~(3-)-H_2O体系中的腐蚀速率的研究

对化学汽相沉积(CVD)的SiO_2、PSG膜在HF-PO_4~(3-)-H_2O体系中的腐蚀速率作了研究。该体系与HF-NH_4F-H_2O体系相比,PSG膜的腐蚀速率及PSG膜与SiO_2膜的腐蚀速率比将会明显地下降。对实验结果在机理上作了定性的探讨。     

光纤损耗谱测量系统

本文叙述了一种光纤损耗谱测量系统。该系统由钨卤素灯、单色仪、硅或铟镓砷检测器及新型数据处理装置组成。无论是单模光纤还是多模光纤,都可在从可见光到波长为1.7μm的光波范围内进行测量,精度可达0.1分贝。     

Buck控制器中仿真电流模式控制电路的设计

论述了一种应用于Buck型开关电源控制器的仿真电流模式控制方法及相应的电路设计。该技术可用于新一代符合VRMIO标准的处理器供电电路。分析了传统电流模式控制在此应用条件下的局限性，提出了利用仿真电流模式实现Buck型开关电源的电流跟踪控制，并分析了电路的工作原理及设计实现。电路采用1．5μm BCD工艺实现。电路与系统的仿真结果表明，所预期的设计要求均已实现。     

一种背栅极冷阴极器件中纳米线表面电场的分析

利用静电场理论计算了背栅极冷阴极器件的纳米线附近电场,给出电场分布的表示式及J-V曲线,并分析了几何参数对纳米线顶端表面电场的影响.结果表明,纳米线顶端表面产生巨大的电场,随着离纳米线顶端表面距离的增大,电场迅速下降;纳米线突出栅孔的长度(L-d1)越大,纳米线半径r0、栅孔半径R以及栅极与阳极间距d2越小,则纳米线顶端表面电场越强,而d2较大时d2对表面电场的影响很弱;纳米线顶端边缘电流密度J随着阳极与栅极电压的增加而指数增大.     

Improvement of Security of Three-Party Quantum Secure Direct Communication Based on GHZ States

A protocol for three-party quantum secure direct communication based on Greenberger-Horne-Zeilinger （GHZ） states was recently proposed by 3in et al. [Phys. Lett. A 354 （2006） 67] By analysing the protocol we find some security loopholes, e.g. one bit of secret messages of a party （Alice in the original paper） can always be leaked straight to the public without any eavesdropping. These problems suggested previously are discussed and possible solutions are presented to improve the security of the original protocol.     

Experimental Study on Electrostatic with Two Guiding of Supersonic D20 Molecular Beam Charged Wires

We demonstrate the guiding of a supersonic heavy-water （D2O） molecular beam using a hollow electrostatic field generated by the combination of two parallel charged-wires and two grounded metal-plates, and report some new and preliminary experimental results. In the experiment, we detect the guiding signals by using the method of time-of-flight mass spectrum and study the dependence of the relative transmission of the beam guide on the guiding voltage. Our study shows that the relative transmission of the beam guide is increased linearly with increasing guiding voltage Vguid, and the number of the guided D20 molecules is at least increased by 89.4% when the guiding voltage is ＋20.0k V. Finally, some potential applications of our guiding scheme in the molecule optics are briefly discussed.     

Hydrogen Passivation Effect on Enhanced Luminescence from Nanocrystalline Si/SiO2 Multilayers

Nanocrystalline Si/SiO2 multilayers are prepared by thermally annealing amorphous Si/SiO2 stacked structures. The photoluminescence intensity is obviously enhanced after hydrogen passivation at various temperatures. It is suggested that the hydrogen trapping and detrapping processes at different temperatures strongly influence the passivation effect. Direct experimental evidence is given by electron spin resonance spectra that hydrogen effectively reduces the nonradiative defect states existing in the Si nanocrystas/SiO2 system which enhances the radiative recombination probability. The luminescence characteristic shows its stability after hydrogen passivation even after aging eight months.