900nm高功率半导体激光器线阵列

利用金属有机化合物气相淀积(MOCVD)技术生长了InGaAs/GaAs分别限制应变单量子阱激光器工作物质.利用它制成半导体激光器线阵列,其峰值波长为900nm,光谱半高全宽小于4nm,在脉宽1000μs、13Hz的输入电流抽运下,输出峰值功率接近60W(室温,电流87A),斜率效率为0.64W/A.     

成核层形貌对AlGaN/GaN异质结晶体质量，表面形貌以及电学特性的影响

Nucleation layer formation is a key factor for high quality gallium nitride（GaN）growth on a sapphire substrate.We found that the growth rate substantially affected the nucleation layer morphology,thereby having a great impact on the crystal quality,surface morphology and electrical properties of AlGaN/GaN heterostructures on sapphire substrates.A nucleation layer with a low growth rate of 2.5 nm/min is larger and has better coalescence than one grown at a high growth rate of 5 nm/min.AlGaN/GaN heterostructures on a nucleation layer with low growth rate have better crystal quality,surface morphology and electrical properties.     

成组技术在先进生产制造模式中的应用和发展

在分析传统成组技术与计算机集成制造系统、精益生产、敏捷制造、柔性制造系统等先进制造模式关系的基础上,指出传统成组技术的缺陷和局限,探讨成组技术的理论发展和实践应用.     

复杂背景下的车牌定位和字符分割研究

提出了一种综合边缘检测、投影特征的车牌定位方法和基于垂直投影及模板匹配的字符分割方法,提取车牌灰度图像边缘,实验结果显示该算法检测边缘的速度快,车牌区域轮廓清晰,采用投影法确定车牌区域,用HOUGH变换检测倾斜角度进而对倾斜的车牌进行矫正,通过字符分割算法对车牌字符进行切割,有效地解决了复杂环境的干扰、车牌尺寸变化等问题。对不同背景下的光照车牌进行了大量实验,结果表明该算法能准确地进行车牌定位以及字符分割,具有较好的鲁棒性。     

灰岩区溶洞与薄层泥岩物探异常差异分析

针对地球物理反演问题存在多解性、单一物探解译成果易与实际情况产生偏差等问题,以区分灰岩区大型溶洞与岩体破碎产生的相似TSP异常、提高超前预报解译精度为目标,将EH4、TSP303及地质雷达技术用于千岛湖配水工程灰岩区不良地质探测。简述了三种物探方法的原理及观测系统设置方式在EH4电磁异常区域开展隧洞超前预报工作,物探成果有效揭示了不良地质的存在。鉴于TSP两次预报异常相似但开挖结果不同,提出了根据TSP纵波速度谱中低速带的分布形态来区分溶洞与破碎岩体的方法。结果表明:大型溶腔与薄层泥岩均对应偏低的纵波波速、密度及杨氏模量,但前者在TSP纵波速度谱中表现为小范围封闭状低速异常,后者低速带呈带状,产状相对清晰;溶洞雷达异常表现为双曲线状同相轴且具备与完整灰岩对比度明显的强振幅特性,薄层泥岩反射能量较溶腔弱,波形杂乱错断,但未呈现明显双曲线特征。     

基于D-H曲线及性能退化的钢闸门寿命预测方法

目前水工钢闸门结构寿命预测公式过于简化,只考虑了锈蚀对闸门构件厚度的影响,同时还将闸门锈蚀过程简化成一个均匀线性的过程。而闸门锈蚀不仅仅影响闸门构件的厚度,对闸门金属材料性能也有很大影响,特别是随着锈蚀程度增加,对材料性能的影响程度也会增加。故本文考虑到锈蚀对闸门材料性能的影响,基于金属材料性能退化规律,结合金属任意损伤与金属日历寿命关系曲线即D-H曲线推导出了新的闸门构件寿命预测的公式,并根据该公式对实际工程中的闸门寿命进行预测。计算结果表明,预测结果与实际结果拟合程度较好,能够更加准确的预测闸门寿命。根据预测的闸门剩余寿命能够判断闸门运行安全状态,以便及时维修或者更换闸门,从而减少闸门失事事故的产生。     

Modified textured surface MOCVD-ZnO:B transparent conductive layers for thinfilm solar cells

Modified textured surface boron-doped ZnO （ZnO：B） transparent conductive layers for thin-film solar cells were fabricated by low-pressure metal organic chemical vapor deposition （LP-MOCVD） on glass substrates. These modified textured surface ZnO：B thin films included two layers. The first ZnO：B layer, which has a pyramid- shaped texture, was deposited under conventional growth conditions, and the second layer, which has a sphere- like structure, at a relatively lower growth temperature. Typical bi-layer ZnO：B thin films exhibit a high electron mobility of 27.6 cm^2/（V.s） due to improved grain boundary states. For bi-layer ZnO：B, the haze value increases and the total transmittance decreases with the increasing film thickness of the second modification layer. When applied in hydrogenated microcrystalline silicon （μc-Si：H） thin-film solar cells, the modified textured surface ZnO：B layers present relatively higher conversion efficiency than conventional ZnO：B films.     

The influence of As and Ga prelayers on the metal-organic chemical vapor deposition of GaAs/Ge

GaAs epilayers were grown on Ge by metal-organic chemical vapor deposition (MOCVD) with As or Ga prelayers. The grown epilayers were examined for surface morphology, antiphase domain (APD) presence, and optical quality using optical interference contrast microscopy, molten potassium hydroxide (KOH) etching, and photoluminescence (PL) spectroscopy. The As prelayer results in smooth, shiny, and APD-free epilayers with good optical quality. In contrast, the Ga prelayer results in a rough surface with APDs and higher carbon incorporation.     

Low threshold current density, highly strained InGaAs laser grown by MOCVD

It is possible to delay the growth mode transition from a 2-D growth mode to 3-D growth mode (the so-called Stranski-Krastanov growth mode) by means of non-equilibrium growth process employing a low growth temperature and a high growth rate, and adopting a high V/III ratio simultaneously to maintain crystal quality. Record emission wavelengths in multiple InGaAs/GaAs quantum wells without a strain-compensated barrier are grown by metal organic chemical vapor deposition (MOCVD). An InGaAs vertical-cavity surface emitting laser (VCSEL) with emission spectrum up to 1.26 μm under CW operation has been realized. Optimizing the quality of InGaAs QWs leads to a low threshold current density. The qualities of the highly strained InGaAs QWs of this VCSEL structure, such as internal quantum efficiency, internal loss, and transparency current density, were investigated by standard broad area (BA) laser process. Combined with an extensive gain-cavity detuning and the high-quality InGaAs QWs, the InGaAs VCSEL, we believe, is a promising candidate for application to long wavelength, low-cost source fiber-optical communication systems.     

空冷汽轮机低压末级系列长叶片的研制

系统地介绍了哈尔滨汽轮机厂有限责任公司空冷机组专用的末级叶片系列的设计要点,该设计针对空冷末级叶片的工作特点,有效地把末级叶片的安全性和经济性结合起来,保证了空冷机组的安全高效运行。