Photoluminescence study of ZnCdSe/ZnSe quantum dot systems

The optical properties of the populated ZnCdSe/ZnSe quantum dots have been studied by photoluminescence spectra measured with different laser excitation apertures at temperatures from 22 to 300 K. The differences of spectral features between small and large excitation spot suggest the existence of quantum dot size fluctuation in the system. The temperature evolution of photoluminescence spectral features revealed that two types of quantum dots with different densities and sizes coexist in ZnCdSe/ZnSe system. The energy spacings of the two kinds of quantum dot emissions are about 50 meV at various temperatures. The thermally activated lateral transfer processes of carriers populated in the two sorts of quantum dots are investigated by temperature dependences of spectral intensities.     

相位型宽频带激光测振仪的研究

在理论上详细描述了一种新型的激光偏振移相干涉测振系统.通过计算机对两路正交干涉光电信号的接收和正弦逼近法数字处理,在1Hz～10KHz宽频带内测量振动台的振幅和初相位,从而实现加速度传感器复合灵敏度的绝对校准.运用琼斯矩阵证明干涉系统中通过偏振片调整可保证两信号的正交性.     

Truncated Estimator of Asymptotic Covariance Matrix in Partially Linear Models with Heteroscedastic Errors

A partially linear regression model with heteroscedastic and/or serially correlated errors is studied here. It is well known that in order to apply the semiparametric least squares estimation （SLSE） to make statistical inference a consistent estimator of the asymptotic covariance matrix is needed. The traditional residual-based estimator of the asymptotic covariance matrix is not consistent when the errors are heteroscedastic and/or serially correlated. In this paper we propose a new estimator by truncating, which is an extension of the procedure in White. This estimator is shown to be consistent when the truncating parameter converges to infinity with some rate.     

Magnetic properties of Fe/Pt films by symmetrical insertion of Ag

Ultrathin Ag (0.5 nm) pinning layers (APLs) were symmetrically inserted into [Fe/Pt] bilayers to introduce controllable defects on the interfaces between Ag and Fe/Pt multilayers. The highest coercivity 7700 Oe and remanent squareness 0.95 were obtained with five APLs. The large enhancement in coercivity (75% increment compared with that without APL) is due to the relative uniform defects that introduced pinning effects on the interfaces between the APLs and Fe/Pt multilayers. According to the distribution of angule- dependent coercivity of Fe/Pt multilayers without and with APLs, a tendency is suggested of weakened domain-wall motion while enhanced rotation of reverse domain mode.     

碘-四氯化碳萃取光度法间接测定痕量草酸根

本研究了在稀硫酸介质中，一定的反应条件下，碘酸根与草酸根反应，稀释出 一定量的碘，据此建立了碘－四氯化碳萃取光度法间接测定草根的方法。反应温度控制在９０℃，反应时间控制在３ｍｉｎ，反应酸度控制在ｐＨ１．０￣２．０，共顾离子基本不干扰测定，草酸根的最低检测限为０．０８μｇ／ｍＬ，通过方法的回收率试验以及与其他测定方法进行比较得到了满意的结果，回收率在９６￣９８％之间。     

Volteera型积分微分方程组边值问题的奇摄动

该文研究二阶积分微分方程组边值问题奇摄动，在适当的条件下，利用渐近分析方法和对角化技巧，还得解的存在性和给出解的渐近展开式与相应的余项估计．然后，应用这些结果到三阶常微分方程组边值问题的奇摄动，最后也得到解的一致有效的渐近展开式．     

马铃薯提取液中生理活性物质的研究 H马铃薯提取液中的内源激素对植物愈伤组织生长和分化的影响

本文证实了马铃薯提取液中存在IAA和ABA.实验结果指出，在马铃薯提取液中ABA的含量比其他内源激素要高.ABA对植物愈伤组织的生长和分化可能起着主导作用.由于马铃薯的品种，发育状况和块茎不同部位的差异，马铃薯提取液对植物愈伤组织的生长和分化的效应也随之而异根据上述情况，必须选择适合的马铃薯块茎作材料，同时在组织培养中应用马铃薯提取液时尚需适当添加NAA和KT.