CdSe核辐射探测器的噪声与漏电流

对具有金属-半导体-金属(MSM)结构的CdSe探测器的噪声进行了实验观测,并对探测器中光生载流子的输运过程进行了分析,结果表明探测器的噪声是由从正极注入的空穴电流引起的.因此只有改变正极接触,才能有效地阻止空穴注入,从而消除探测器噪声.     

Growth of Erbium Dihydride Films under Low Hydrogen Pressure by Pulsed Laser Deposition

Erbium dihydride thin films were prepared by pulsed laser deposition on Si(100) substrates using erbium target under different low hydrogen pressures. The properties of these films were examined by atomic force microscopy, X-ray diffractometer, transmission electron microscopy, and Fourier transform infrared spectroscopy and UV-vis spectroscopy. Surface morphology reveals the smooth surface of these films(RMS: from 0.503 to 2.849 nm). The presence of obviously-broadened peaks for diffraction planes(111) suggests a presence of very tiny crystallites distributed along a preferred crystallographic orientation. Transmission electron microscopy investigations confirmed the formation of tiny crystallites due to the implantation of erbium ions. Due to the increase of nominal H concentration, the intensity of the broad absorbance from 190-260 nm increased.     

Influence of multilayer coatings on AZ31 deposited by electron beam evaporation

Three different coatings, Cr, SiO2/Cr and HfO2/SiO2 were deposited by electron beam physical vapor deposition （EB-PVD）. Relevant composition and mechanical properties were obtained. The results show that the surface mechanical property could be increased, and Cr coating sample possessed the highest microhardness. Cyclic oxidation in air at 773 K was applied to evaluate the oxidation resistance of the coatings, and the section morphologies of the coatings were observed by FEISEM. The results indicate that the oxidation rate of AZ31 with Cr, SiO2/Cr and HtO2/SiO2 coatings is decreased, and the SiO2/Cr coating sample exhibits the best oxidation resistance and keeps relatively good adhesion up to 96 h. Polarization results prove that the corrosion resistance ofAZ31 can be improved and the SiO2/Cr coating sample has the best property.     

基于环型电网的输电线路相序排列方法研究

同塔多回输电线路之间存在着复杂的电磁耦合关系,当其合环后,各段线路本身的不平衡相互叠加,加剧了环型电网的三相不平衡性。为了减小环型电网的三相不平衡性,结合线路相序排列方式进行研究。通过分析环型电网中的线路电流与线路阻抗之间的关系,提出了环型电网中各段线路采用同一相序排列方式,能够大幅度降低环型电网中的线路不平衡度。通过对双回线路组成的环型电网进行PSCAD/EMTDC建模分析,并对不同相序排列下的不平衡度进行对比。结果证明了两回线路均采用同相序或逆相序排列时,线路不平衡度较小,为环型电网的最优相序排列提供了理论依据。     

浅谈插花艺术

对中外插花的起源进行了概述，根据不同标准对插花进行了分类，并对插花基础、插花道具及花材的选择进行了综合介绍。     

CdSe探测器的制备与性能

通过测定CdSe室温核辐射探测器的伏安曲线和能谱特性，对探测器制作过程中的表面处理工艺进行了初步研究，结果表明通过适当的表面腐蚀和钝化处理，可以降低表面漏电流，减小探测器噪声，达到提高探测器能量分辨率的目的。     

羊乳中替米考星残留的检测方法研究

建立了羊乳中替米考星残留的反相高效液相色谱检测方法。羊乳按1:1(V/V)用乙腈提取,上清液以5ml/min 流速过C18 SPE 柱,采用乙腈- 水(20:80,V/V)洗涤、乙腈- 水(90:10,V/V)洗脱,并以0.1mol/L 乙酸铵- 乙腈-甲酸(60:30:10,V/V)为流动相,采用高效液相色谱仪在280nm 处使用紫外检测器检测。本法定量限(LOQ)为0.02μg/ml,平均回收率范围在90.3%～98.1% 之间,线性范围为0.01～25μg/ml,变异系数范围在4.1%～8.9% 之间。本法可满足残留分析的要求,为羊乳中替米考星的残留分析提供了可靠的检测方法。     

GaAs/AlGaAs多层膜刻蚀的陡直度

GaAs/AlGaAs多层膜的陡直度较大程度地关系到其实际应用效果,但在实际加工中较难控制,因此有必要研究刻蚀过程中一些主要因素对其陡直度的影响。结合具体工作情况,用AZ1500光刻胶作为掩模,GaAs/Al0.15Ga0.85As多层膜为刻蚀材料,分别使用湿法和干法对其进行刻蚀。湿法刻蚀的刻蚀剂为H3PO4+H2O2溶液,干法刻蚀采用感应耦合等离子体(ICP)刻蚀法,等离子体由Cl2+BCl3(蒸汽)混合气体电离形成。通过控制变量方法,发现湿法刻蚀中刻蚀剂配比和温度以及干法刻蚀中BCl3(蒸汽)流量对刻蚀陡直度的影响规律。由此得出,提高H3PO4所占比例和降低刻蚀温度虽然会降低刻蚀速率,但可以提高多层膜的陡直度;ICP刻蚀的陡直度优于湿法刻蚀,BCl3(蒸汽)的流量在一定范围内对刻蚀陡直度的影响较小。