俄罗斯沙棘优良品种引种试验研究

三北"地区和黄土高原是中国沙棘亚种的分布中心,现已有大面积人工沙棘林,但其果小、刺多,产果量低,采果难。为此,作者于1997~2006年承担水利部"948"沙棘引进项目,以解决该地区沙棘优良品种缺乏问题。通过8年试验研究,引进俄罗斯大果无刺沙棘优良品种、类型40余种,分别在"三北"和黄土高原地区的7个主要试验基地进行引种试验,从中初步筛选出效果较好的9个优良品种、类型。它们生长发育良好,抗性较强,具高产、优质特性,并已开始利用引进的俄罗斯沙棘与当地中国沙棘杂交,培育出第一代杂交种。在引种选育和对俄罗斯沙棘生物生态学特性进行试验研究的基础上,对其良种的集约栽培和繁育做了试验和示范推广工作,产生了良好的生态、经济效益。通过本项目实施,为做好沙棘引种选育工作提供了良种,这对大面积建造高产、优质人工沙棘林和沙棘果园,加速黄土高原和"三北"地区的环境治理、发展地方经济具重要意义。

可溶性甲壳素制取及其稀溶液性质的研究

从螃蟹壳中提取出甲壳素，并进一步进行脱乙酰基反应，制得了脱乙酰度（D.D）在49－100％范围的阳离子聚电解质可溶性甲壳素－壳聚糖。首次通过壳聚糖乙酸溶液的超声波降解快速制得了各个脱乙酰度系列，不同分子量的壳聚糖样品。将不同系列的各个样品在0.2M CH_3COOH + 0.1M CH_3COONa溶液中进行粘度和光散射（L.S）的研究，订定出了不同D.D壳聚糖的Mark-Houwink方程（30±0.05℃）如下：69％：[η]=0.1036*10~(-3) M_w~(1.12) (ml/g) 84%: [η]=1.424*10~(-3) M_w~(0.96) (ml/g) 91%: [η]=11.27*10~(-3)M_w~(0.84) (ml/g) 100%: [η]=16.80*10~(-3)M_w~(0.81) (ml/g)同时，对壳聚糖的其它某些稀溶液性质，如分子尺寸，第二维利系数，扩散因子等进行了求算，并对结果进行了讨论。将胶体滴定法应用到聚电解质壳聚糖的脱乙酰度（D.D）分析上，取得了满意的结果，建立了完整的测试方法，推导出了计算公式：D.D=(N_(PVSK)*ΔV*M_壳)/(5*C)*100%式中：N_(PVSK)-PVSK的当量浓度M_壳－完全脱乙酰基的壳聚糖链节分子量：161.15ΔV－消耗掉PVSK的体积差ΔV=V_1-V_2（升）C－壳聚糖溶液的浓度(g/ml)实验表明，不同D.D值的壳聚糖有着不同的折光指数增量dn/dc，由此创立了一个根据测dn/dc值求壳聚糖脱乙酰度的新方法。在0.2M CH_3COOH/0.1M CH_3COONa中，436nm，25±0.05℃时的计算公式如下：y=9.397*0.943式中：x-dn/dc (ml/g) y-D.D (%)。

Photoluminescence of ZnS clusters in zeolite-Y

Two obvious emissions are observed from the ZnS clusters encapsulated in zeolite-Y. The emission around 355 nm is sharp and weak, locating at the onset of the absorption edge. The band around 535 nm is broad, strong and Stokes-shifted. Both the two emissions shift to blue and their intensities firstly increase then decrease as the loading of ZnS in zeolite-Y or clusters size decreases. Through investigation, the former is attributed to the excitonic fluorescence, and the latter to the trapped luminescence from surface states. The cluster size-dependence of the luminescence may be explained qualitatively by considering both the carrier recombination and the nonradiative recombination rates. Four peaks appearing in the excitation spectra are assigned to the transitions of 1S-1S, 1S-1P, 1S-1D and surface state, respectively. The excitation spectra of the clusters do not coincide with their absorption spectra. The states splitted by quantum-size confinement are detected in the excitation spectra, but could not be differentiated in the optical absorption spectra due to inhomogeneous broadening. The size-dependence of the excitation spectra is similar to that of the absorption spectra. Both the excitation spectra of excitonic and of trapped emissions are similar, but change in relative intensity and shift in position are observed.

A RESONANT RAMAN-STUDY ON PHONONS IN GAINAS/ALINAS MULTIPLE-QUANTUM WELLS

The LO phonon modes in the barrier layers of a GaInAs/AlInAs multiple quantum well structure are investigated by resonance Raman scattering (RRS), the excitation laser photon energy tuned to resonate with the above barrier interband transition energy. The resonance enhancement of LO phonon peaks are shown to be caused by Frohlich electron-phonon interaction. The pressure-dependent profiles for both AlAs-like (LO(2) mode) and InAs-like (LO(1) mode) Raman peak intensities are well fitted by the Gaussian lineshape. The shift between these two profiles can be explained by the outgoing RRS mechanism, providing information on the pressure-induced shift of the excitonic transition energy. The amplitude ratios of the two profiles are close to 1, showing a well defined two-mode behavior and the nearly equal polarizability for Al-As and In-As bonds in AlInAs alloy.

Resonant Raman Scattering and Photoluminescence Emissions from Above Bandgap Levels in Dilute GaAsN Alloy

The transitions of E0 ,E0 ＋A0, and E＋ in dilute GaAs（1-x） Nx alloys with x = 0.10% ,0.22% ,0.36% ,and 0.62% are observed by micro-photoluminescence. Resonant Raman scattering results further confirm that they are from the intrinsic emissions in the studied dilute GaAsN alloys rather than some localized exciton emissions in the GaAsN alloys. The results show that the nitrogen-induced E E＋ and E0 ＋ A0 transitions in GaAsN alloys intersect at a nitrogen content of about 0.16%. It is demonstrated that a small amount of isoelectronic doping combined with micro-photoluminescence allows direct observation of above band gap transitions that are not usually accessible in photoluminescence.

有效去除图像中脉冲噪声的新型滤波算法

提出一种基于局部极值噪声检测的迭代中值滤波算法。该算法集中了minmax算法与PSM算法各自的优势，并将两种算法有机地结合起来，经过实验仿真并与其他滤波算法进行比较表明，该算法可以有效地去除图像中的脉冲噪声，尤其是在噪声密度非常大的情况下表现了很好的性能。

InAs自组织生长量子点的空穴俘获势垒

成功地用深能级瞬态谱(DLIS)研究了p型InAs自组织生长的量子点的电学性质，测得2.5原子层InAs量子点空穴基态能级在GaAs价带底上约0.09eV,该量子点在荷电状态发生变化时需要克服一个势垒，俘获势垒高度为0.26eV。首次利用DLTS测定了量子点空穴的基态能级和俘获势垒，相信对增加量子点性质的理解会起到有益的帮助。

High power 980 nm InGaAs/AlGaAs strained quantum well lasers

于2010-11-23批量导入

Pt-Ni/p-InP低阻欧姆接触的机理研究

利用X射线衍射和AES(俄歇)方法，深入地研究了RF磁探溅射淀积的Pt-Ni/p-InP(100)非合金膜系在热退火过程中Pt和Ni与衬底InP中的In和P形成稳定化合物的行为，揭示了比接触电阻降低于3×10~(-6)Ω·cm~2的根本原因。

The design of cascaded resistors in a new analog switch two-step ADC architecture

In this paper we introduce a new Half-flash analog switch ADC architecture. And we discuss two methods to design the values of the cascaded resistors which generate the reference voltages. Derailed analysis about the effect of analog switches and comparators on reference voltages, and the methods to set the resistor values and correspond;ng voltage errors are given.