Proof of InAs/GaAs self-organized quantum dot lasing and the experimental determination of local Strain effect on the band structures

Confirmation of quantum dot lasing have been given by photoluminescence and electro-luminescence spectra. Energy levels of QD laser are distinctively resolved due to band filling effect, and the lasing energy of quantum dot laser is much lower than quantum well laser. The energy barrier at InAs/GaAs interface due to the built-in strain in self-organized system has been determined experimentally by deep level transient spectroscopy (DLTS). Such barrier has been predicted by previous theories and can be explained by the apexes appeared in the interface between InAs and GaAs caused by strain.

Low-temperature growth of cubic GaN by metalorganic chemical-vapor deposition

Low-temperature growth of cubic GaN at 520 degrees C was achieved using CCl4 as an additive by metalorganic chemical-vapor deposition (MOCVD) on GaAs substrate. X-Ray measurement confirmed that the films are single-phase cubic GaN. Scanning electron microscopy (SEM) and reflection high-energy electron diffraction (RHEED) were also used to analyze the surface morphology and the quality of films. The evolution of surface morphology suggests that CCl4 can reduce the hopping barrier and thus Ga adatoms are able to diffuse easily on the GaN surface. (C) 1998 Elsevier Science S.A. All rights reserved.

Heteroepitaxial Growth of 3C-SiC on Si (111) Substrate using AlN as a Buffer Layer

Using AlN as a buffer layer, 3C-SiC film has been grown on Si substrate by low pressure chemical vapor deposition (LPCVD). Firstly growth of AlN thin films on Si substrates under varied V/III ratios at 1100 degrees was investigated and the (002) preferred orientational growth with good crystallinity was obtained at the V/III ratio of 10000. Annealing at 1300 degrees C indicated the surface morphology and crystallinity stability of AlN film. Secondly the 3C-SiC film was grown on Si substrate with AlN buffer layer. Compared to that without AlN buffer layer, the crystal quality of the 3C-SiC film was improved on the AlN/Si substrate, characterized by X-ray diffraction (XRD) and Raman measurements.

Highly efficient and stable organic light-emitting diodes employing MoO3-doped perylene-3, 4, 9, 10-tetracarboxylic dianhydride as hole injection layer

We report highly efficient and stable organic light-emitting diodes (OLEDs) with MoO3-doped perylene-3, 4, 9, 10-tetracarboxylic dianhydride (PTCDA) as hole injection layer (HIL). A green OLED with structure of ITO/20 wt% MoO3: PTCDA/NPB/Alq(3)/LiF/Al shows a long lifetime of 1012 h at the initial luminance of 2000 cd/m(2), which is 1.3 times more stable than that of the device with MoO3 as HIL. The current efficiency of 4.7 cd/A and power efficiency of 3.7 lm/W at about 100 cd/m(2) have been obtained. The charge transfer complex between PTCDA and MoO3 plays a decisive role in improving the performance of OLEDs.

“中介逻辑”与Woodruff三值逻辑系统

在《“中介逻辑”的特征问题》一文里,我们对近来朱梧梗、肖奚安等同志发表的称为“中介逻辑”的命题系统MP的三个联接词(对立否定),～(模糊否定)与→(蕴含)建立了如下的三值真值表:

用双切比雪夫方法近似含噪音移动对象轨迹

在移动对象数据库中需要存储大量移动对象的历史轨迹。为了降低存储开销，同时提高轨迹查询的效率，研究者们提出了很多基于时间序列的方法对轨迹序列进行压缩近似及索引。但是这些方法不能用于不精确的轨迹数据。本文针对含噪音的轨迹数据提出了一种新的近似算法。该方法充分利用了轨迹位置数据和速度数据的导数关系，在不增加计算复杂度的情况下，能够更好地处理不精确的轨迹。在相同的压缩比下，用双切比雪夫方法重建的轨迹比现有方法更加接近移动对象的真实轨迹。

a simple but effective improvement to the plumb-line algorithm

Emporiki Bank; Microsoft; Alpha Bank

两段厌氧消化法处理甘蔗糖蜜酵母废水实验室研究

本文报道应用两段系统和上流式污泥床与过滤层结合型反应器的厌氧消化工艺处理甘蔗糖蜜酵母废水的研究方法及其获得的良好结果。当反应温度为35℃，反应器容积负荷为12gCOD/1·d时，进水COD_(cr)浓度为10，000mg/l，pH值为4.5，水力停留时间为0.83天，出水COD_(cr)浓度为3300—2700mg/l，pH值为7.1，COD_(cr)去除率为67—73%，反应器容积产气率在31/1.d以上，甲烷含量为70%左右，每克COD的沼气产量为0.251。