基于AlAs氧化法研制的垂直腔面发射激光器

结合垂直腔面发射激光器的制备,研究了AlAs选择性氧化工艺中氧化炉温、氮气流量、水温等条件和AlAs层的横向氧化速率之间的关系,并得到了可精确控制氧化过程的工艺条件,在优化的工艺条件下运用湿氮氧化制备出InGaAs/GaAs垂直腔面发射激光器,实现了器件的室温脉冲激射.     

Influence of dry and wet cleaning on the properties of rapid thermal grown and deposited gate dielectrics

Various silicon surface cleaning processes for rapid thermal in-situ polysilicon/ oxide/silicon stacked gate structures have been evaluated. Metal-oxide-semiconductor capacitors were fabricated to assess the effects of cleaning on the quality of gate oxide structures produced by both rapid thermal oxidation (RTO) and rapid thermal chemical vapor deposition (RTCVD). Excellent electrical properties have been achieved for both RTO and RTCVD gate oxides formed on silicon wafers using either an ultraviole/zone (UV/O₃) treatment or a modified RCA clean. On the contrary, poor electrical properties have been observed for RTO and RTCVD gate oxides formed on silicon wafers using a high temperature bake in Ar, H₂, or high vacuum ambient. It has also been found that the electrical properties of the RTCVD gate oxides exhibit less dependence upon cleaning conditions than those of RTO gate oxides. This work demonstrates that initial surface condition prior to gate oxide formation plays an important role in determining the quality of RTO and RTCVD gate oxides.     

Al2O3／TiB2和Al2O3／TiB2／SiCW陶瓷材料氧化层的显微结构分析

用Ｘ射线衍射，扫描电子显微镜和透射电镜／能谱仪分析了Ａｌ２Ｏ３／ＴｉＢ２和Ａｌ２Ｏ３／ＴｉＢ２／ＳｉＣＷ陶瓷材料在１３００℃氧化３０小时后氧化层的相组成及显著结构。     

氯盐腐蚀条件下钢筋混凝土结构抗力衰减模型研究

采用改进的Fick第二扩散定律来描述混凝土内氯离子的扩散过程,从而可以预测混凝土内钢筋开始锈蚀的时间;建立了均匀腐蚀、点腐蚀以及两者同时存在条件下的钢筋腐蚀速度模型,为结构抗力衷减规律的研究奠定了基础。算例表明建立的模型是合理的。     

催化重整系列脱氯剂的研究与应用

介绍了催化重整工艺中HCl的来源与危害，讨论了脱氯剂在预加氢及重整氢和再生气脱氯中的应用及其特点。简要介绍了T型脱氯剂的概况，着重介绍了T型中三种新型脱氯剂的特点与应用。对在研究和应用过程中的脱氯剂构成、使用条件控制、催化剂中毒、氯容问题、硫影响问题、结块问题等诸多问题进行了探讨。     

空心钛硅分子筛在二甲基硫醚液相氧化反应中的催化性能

在以过氧化氢为氧化剂的二甲基硫醚液相氧化反应体系中,对空心钛硅分子筛（HTS）的催化性能进行了系统研究,详细考察了催化剂存在与否以及催化剂用量、反应时间、反应物料配比及溶剂用量等不同反应条件变化对二甲基硫醚温和液相氧化反应的影响。研究发现,在温和反应条件下,HTS催化二甲基硫醚氧化反应中主要产物是二甲基亚砜和二甲基砜。经优化后,能够获得较好的氧化二甲基硫醚制备二甲基亚砜的反应效果,在二甲基硫醚转化率超过99%的情况下,二甲基亚砜选择性可达95%以上。     

Ir/HfO2复合涂层的制备及性能研究

利用化学气相沉积(CVD)技术制备了HfO2涂层和Ir/HfO2复合涂层,采用金相显微镜(OM)、扫描电镜(SEM)、电子探针(EPMA)对涂层的性能进行分析。结果表明:在沉积Ir时,沉积室升温速率≤10 ℃/min时,制备出的Ir/HfO2复合涂层经真空高温热处理后可获得表面质量良好的Ir层,且Ir层纯度达到99.77%;真空热处理有益于提高Ir/HfO2复合涂层之间的结合程度,且热处理温度越高,结合效果越好;表面制备有HfO2涂层的Ir棒在1980 ℃氧化10 h的条件下,HfO2涂层对Ir的保护效果显著,可将Ir的氧化深度由毫米级降至数十微米。     

Strong Electronic Interaction of Amorphous Fe2O3 Nanosheets with Single‐Atom Pt toward Enhanced Carbon Monoxide Oxidation

Platinum‐based catalysts are critical to several chemical processes, but their efficiency is not satisfying enough in some cases, because only the surface active‐site atoms participate in the reaction. Henceforth, catalysts with single‐atom dispersions are highly desirable to maximize their mass efficiency, but fabricating these structures using a controllable method is still challenging. Most previous studies have focused on crystalline materials. However, amorphous materials may have enhanced performance due to their distorted and isotropic nature with numerous defects. Here reported is the facile synthesis of an atomically dispersed catalyst that consists of single Pt atoms and amorphous Fe₂O₃ nanosheets. Rational control can regulate the morphology from single atom clusters to sub‐nanoparticles. Density functional theory calculations show the synergistic effect resulted from the strong binding and stabilization of single Pt atoms with the strong metal‐support interaction between the in situ locally anchored Pt atoms and Fe₂O₃ lead to a weak CO adsorption. Moreover, the distorted amorphous Fe₂O₃ with O vacancies is beneficial for the activation of O₂, which further facilitates CO oxidation on nearby Pt sites or interface sites between Pt and Fe₂O₃, resulting in the extremely high performance for CO oxidation of the atomic catalyst.