一种零电压转换有源功率因数校正电路的研究

提出了一种基于UC3854的零电压转换有源功率因数校正(ZVT-APFC)的控制电路实现方案,介绍了ZVT电路工作原理,着重分析了由分立元件构成的辅助开关管的驱动电路,通过实验证实了驱动电路的稳定性和可靠性,并通过效率比较验证了ZVT-APFC电路的优良性能。与采用UC3855的电路相比,该电路方案具有简单、可靠、成本低等优点。     

二氧化锡溅射工艺研究

SnO2 是最早使用也是目前使用最广泛的一种气敏材料 ,使用该材料设计制作的气敏传感器具有许多优点。在简要介绍溅射镀膜的成膜过程和特点的基础上 ,着重介绍了SnO2 膜的制备流程 ,分析了功率和温度变化对成膜质量的影响     

A new molecular rectifier device and some research in its processing

Organic materials of D-π-A type MR-X (MR-1: p-dimethylaminophenylethenetrica-rbonitrile and MR-2: p-diphenylaminophenylethene tricarbonitrile) were designed and synthesized. The device with a sandwich structure shows good rectificative phenomena. The highest rectification ratio 10000 was achieved in device Cu/MR-1/Ag, and about 100 in other device M/MR-X/M (M: Cu, Ag). It has been found that rectificative phenomena exist only in the atmosphere-liquid interface region by means of liquid adsorption, and electric field could help form the oriented molecular film. __________ Translated from Journal of Fudan University (Natural Science), 2005, 44(4) (in Chinese)     

大功率CO2激光器脉冲电源研究

本文论述了直流高压与高频脉冲电源相叠加，构成高频、高压脉冲电源，并使其对CO2激光器进行放电实验，研究了同条件下的放电参数与功率。     

经济实用的DSP电源解决方案

笔者介绍了两种低纹波的DSP电源解决方案:一为采用MAX1793和大电流EMI静噪滤波器NFM41P;二为改进的去耦p型滤波电路和大电流EMI静噪滤波器NFM41P。并对方案的特点及其实现进行了详细的解析。试验结果表明:所述方案的纹波小,仅100 mV左右;成本低,仅几十元;适用范围广,通过改变MAX1793芯片的输出电压,可将本方案移植到TI的C5000,C6000系列,且还可用于其他的脱机工作系统。     

PMN-PT陶瓷中的氧缺位及其消除

研究了组成中Pb含量的变化对组成为Pbx(Mg1/3Nb2/3)0.65Ti0.35O3的铌镁酸铅-钛酸铅(PMN-PT)陶瓷压电性能的影响,发现化学计量比组成(x=1)的Pbx(Mg1/3Nb2/3)0.65Ti0.35O3陶瓷经常出现压电性能的大幅度退化现象,而A位适量缺Pb能稳定地获得高性能的Pbx(Mg1/3Nb2/3)0.65Ti0.35O3陶瓷。XPS元素价态分析的结果表明,化学计量比的Pbx(Mg1/3Nb2/3)0.65Ti0.35O3陶瓷中含有较多的氧缺位,氧缺位的产生源于MgNb2O6(MN)合成过程中的气氛差异,A位适量缺Pb能有效地消除这种氧缺位而稳定地获得正常的压电性能,其机理被认为是氧缺位与铅缺位的复合。     

Boundedness of commutators on homogeneous Herz spaces

The boundedness on homogeneous Herz spaces is established for a large class of linear commutators generated by BMO(R ⁿ ) functions and linear operators of rough kernels which include the Calderón-Zygmund operators and the Ricci-Stein oRfiUatory singular integrals with rough kernels. Project supponed in pan by the National h’atural Science Foundation of China (Grant No. 19131080) and the NEDF of China.     

The correlation of texture and magnetic properties in Co-Cr films

This investigation focuses on the correlation between the crystallographic orientation of grains with respect to magnetic properties in Co-Cr films. Based on a distribution measured for the (0002) crystallographic pole densities, modified formulae describing the texture were used to calculate the coercivity Hc, the squareness ratio Rs (Mr⊥/TMs) and the anisotropy field Ha for Co-Cr films. In general, calculated values for the coercive force He agreed well with the measured values. The calculated Rs⊥. values were much larger than the measured ones, however, indicating that the influence of the demagnetizing field and the magnetostriction on the orientation of the magnetization cannot be neglected. On leave from Institute of Computing Technology, Academia Sinica, P.O.Box 2704-6, Beijing, P.R. China.     

Diastereoselective Alkylation of (Diene-Aldehyde)Fe(CO)3 Complexes with Functionalized Zinc-Copper Reagents NuCu(CN)Znl

Addition of functionalized zinc-copper reagents to the title complexes proceeds in a highly diastereoselective fashion to afford dienol complexes. The relative configurations of adducts 3d were determined by single X-ray diffraction analysis.     

环状连续强激光下光学薄膜的瞬温和热畸变

详细研究了非冷却光学薄膜元件在环形激光光束辐照下的瞬态温度分布和随后的热畸变，并且用泰曼干涉仪实际测量了连续波氧碘激光辐照各种非冷却光学元件的热畸变量并与理论计算相比较，分析结果表明理论和实验相一致。