Triclinic deformation and anisotropic strain relaxation of an InAs film on a GaAs(001) substrate measured by a series of symmetric double crystal X-ray diffraction

We presented a series of symmetric double crystal X-ray diffraction (DCXD) measurements, (0 0 4), (2 2 0) and (2 - 2 0) diffraction, to investigate the strain relaxation in an InAs film grown on a GaAs(0 0 1) substrate. The strain tensor and rotation tensor were calculated according to the DCXD results. It is found that the misfit strain is relaxed nearly completely and the strain relaxation caused a triclinic deformation in the epilayer. The lattice parameter along the [1 1 0] direction is a little longer than that along the [1 - 1 0] direction. Furthermore, a significant tilt, 0.2 degrees, towards the [1 1 0] direction while a very slight one: 0.002 degrees, towards [1 - 1 0] direction were discussed. This anisotropic strain relaxation is attributed to the asymmetric distribution of misfit dislocations, which is also indicated by the variation of the full-width at half-maximum (FWHM) of (0 0 4) diffraction along four azimuth angles. (C) 1998 Elsevier Science B.V. All rights reserved.

Lateral intersubband photocurrent study on InAs/InAlas/InP self-assembled nanostructures

We present lateral intersubband photocurrent (PC) study on self-assembled InAs/InAIAs/InP(001) nanostructures in normal incidence. With the help of interband excitation, a broad PC signal has been observed in the photon energy range of 150-630 meV arising from the bound-to-continuum intersubband absorption in the InAs nanostructures. The large linewidth of the intersubband PC signal is due to the size inhomogeneity of the nanostructures. With the increase of the interband excitation the intersubband PC signal firstly increases with a redshift of PC peak and reaches its maximum, then decreases with no peak shift. The increase and redshift of the PC signal at low excitation level can be explained by the state filling effect. However, the decrease of PC signal at high excitation level may be due to the change of the mobility and lifetime of the electrons. The intersubband PC signal decreases when the temperature is increased, which can be explained by the decrease of the mobility and lifetime of the electrons and the thermal escape of electrons.

基于自索引的DBF压缩查询工具研究

介绍了DBF表的文件格式和基于自索引的全文查询算法FM-index.针对DBF文件同时包含二进制文件头和纯文本数据记录的特点,以及对查询结果的特定要求,扩充了现有的FM-index算法,使其支持对DBF文件的压缩查询.测试结果表明,虽然FM-index在压缩/解压时间上与WinRAR仍有一段差距,但是FM-index对压缩查询功能的支持大大提高了文件的查询性能.

PIBG Toolkit:一个笔式界面工具箱的分析与设计

PIBG Toolkit是一个基于PIBG交互范式构造而成的笔式应用开发平台:PIBG Toolkit中包含了纸、框等多种交互组件，定义了纸、框和内容三个层次之间的静态结构和动态机制: 开发者开发笔式交互系统时，可以用PIBG Toolkit来建立整体的软件框架和交互机制，并有选择地在系统中添加Toolkit中所提供的交互组件.这样，开发者的精力将会集中在应用领域的内容上.目前，基于该平台已经开发出多个具有很好应用前景的笔式应用系统.

茚基稀土铁双核配合物的合成

本文通过元素分析，红外光谱，垫失重，质谱，核磁共振以及电子能谱的测定，确认合成了下述两种新型的过程金属稀土有机配合物：<1> NdCl_3 + NaCaH_7 →~(THF) C_9H_7NdCl_2·nC_4H_8O C_9H_7NdCl_2 · nC_4H_8O + NaFeC_5H_5 (co)_2·mC_4H_8O →~(THF) Na[C_9H_7NdCl_2Fe(co)_2C_5H_5]·C_4H_8O <2> SmCl_3 + NaC_9H_7 →~(LiCl)_(THF) C_9H_7SmCl_2·(LiCl)_2·nC_4H_8O C_9H_7SmCl_2·(LiCl)_2·nC_9H_8O + NaFe(co)_2C_5H_5·mC_4H_8O → Li_2[(C_9H_7SmCl_3·Fe(co)_2C_5H_5]·C_4H_8O这些化合物可涂于四氢呋喃，氯仿，丙酮，三氯乙酸，吡喀算溶剂，不溶于四氯化碳，汽油，笨等涤剂。对水和空气敏感，同硝酸发生激烈的反应。化合物的红外光谱图中1010cm~(-1)，865cm~(-1)为茚基特征吸收峰，1045cm~(-1), 910cm~(-1)为四氢呋喃分子的特征吸收峰。化合物垫失重图中出现了脱去一个四氢呋喃分子和两个羰基的垫失重谱。本文制备配体GH_7LnCl_2nTHF过程中，合成了一类新型的离子型金属有机配合物。通过元素分析，热失重，红外光谱的测定，确定了合成的化合物组成为[Na[C_4H_8O)_6][(CGH_7)_3Ln)_2Cl] 2 LnCl_3 + 6 NaC_9H_7 →~(THF) [(CGH_7)_3Ln)_2Cl][Na(C_4H_8O)_6] Ln = Nd, Sm 并测得了其晶体结构，Nd[Sm]的晶胞参数为：a = 12.553[12.550](A) b = 12.696 [12.653] (A) c = 10.630 [10.608] (A) α = 97.37 [97.76] (°) β = 91.65 [91.83] (°) γ = 87.19 [86.76] (°) V = 1672.4 [1665.9] (°)此类化合物的晶胞体积有V_(Nd) > V_(Sm)现象，符合镧系收缩的规律。化合物热失重图中表明，有27.5%的失重，相当于失去了六个四氢呋喃分子。化合物的红外光谱图中，1015cm~(-1), 865cm~(-1)为茚基特征吸收峰1055cm~(-1), 910cm~(-1)为四氢呋喃分子的特征吸收峰。这些化合物溶于四氢呋喃，不溶于汽油。对水和空气敏感。

阵列波导光栅解复用器输入/输出波导结构串扰的数值分析

采用Marcatili方法分析矩形波导的模场特性，在此基础上计算了AWG波分复用／解复用器串扰与输入／输出波导间隙参数，波导结构参数V的变化关系。计算了串扰值一定时，选取V参数与dr/w的关系曲线。分析了在同不折射率差波导中，串扰与偏振的相关性，为器件的整体优化设计提供了参考数据。

求复折射率波导本征值的打靶法

给出了求一维缓变复折射率波导征值的打靶法,它是对求一维实折射率波导本征值的打靶法的推广。利用它可以分析增益或损耗对TE和TM模式的影响，并给出了计算实例。