In situ FT-infrared investigation of CO or/and NO interaction with CuO/Ce0.67Zr0.33O2 catalysts

In situ FT-IR was employed to investigate CO or/and NO interaction with CuO supported on Ce_0.67Zr_0.33O₂ (hereafter denoted as CZ) catalysts. The physicochemical properties of CuO–CZ were also studied by combination of XRD, TPR and NO + CO activity tests. The results indicated that the dispersed CuO species were the main active components for this reaction. The catalysts showed different activities and selectivities at low and high temperatures, which should be resulted from the reduction of dispersed copper oxide species. This reaction went through different mechanisms at low and high temperatures due to the change of active species. FT-IR results suggested: (1) CO was activated by oxygen originating from CZ support, which led to surface carbonates formation, and partial dispersed CuO was reduced to Cu⁺ species above 150 °C; (2) NO interacted with the dispersed CuO and formed several types of nitrite/nitrate species, whereas crystalline CuO made little contribution to the formation of new NO adsorbates; (3) NO was preferentially adsorbed on CuO–CZ catalysts compared with CO in the reactants mixture. These adsorbed nitrite/nitrate species exhibited different thermal stability and reacted with CO at 250 °C. As a result, a possible mechanism was tentatively proposed to approach NO reduction by CO over CuO–CZ catalyst.     

SiGe合金单晶生长研究

通过改进SiGe单晶生长热场和Ar气流动方式,并采用合适的生长速度,优化调整SiGe单晶生长控制工艺参数,有效控制了SiGe单晶的位错密度.采用直拉(CZ法)在国产TDR-62Si单晶炉上,采用150 mm密闭式热系统,生长出了Ge质量分数为9.79%～12.92%、φ为50～60mm的SiGe单晶.可应用于X射线单色器、探测空间γ射线的透镜及热电器件,还可用作部分光电器件和量子阱器件SiGe同质外延生长的衬底.     

LY12CZ基材表面阳极氧化膜局部发黑成因

LY12CZ基材零件硫酸阳极氧化后表面常出现发暗、发黑的非正常现象,影响产品质量和性能.采用SEM、金相分析等手段对基材和阳极氧化膜进行了综合分析,得出产生此现象的主要原因是:因氧化前热处理不当,基材本身产生了大量的残留杂质相和富Cu相,使阳极氧化膜中出现夹杂和空洞,导致氧化膜出现发黑现象.对基材进行二次热处理可有效解决这一问题.     

世界半导体硅工业新动向

文章从技术和市场两方面概括了近年来世界半导体硅工业的新动向。评述了单晶中的氧行为,CLF-CZ、FCCZ、MCZ等方法的应用,分析了硅工业的发展方向与国际市场的变化。     

LY12CZ厦门海域全浸区和潮差区腐蚀结果分析

应用灰色关联分析的方法,分别对厦门海域全浸区和潮差区影响LY12CZ均匀腐蚀和点蚀的海洋和气象环境因素进行了分析处理,得到各种影响因素的关联度排序,根据铝合金全浸区和潮差区腐蚀失效机理对排序结果进行了分析,处理结果可信,该方法适合于处理影响因素复杂的LY12CZ腐蚀数据.     

2A11-CZ硬质铝合金加工工艺参数研究

通过对2A11-CZ铝合金成分和组织结构的分析,找出了2A11-CZ硬铝性能与特性形成的原因;根据其性能与特性要求找出了确定其加工工艺参数的方法。     

我国半导体硅材料的发展现状

叙述了我国半导体硅材料的发展现状及与国外相比存在的差距 ,提出了发展我国硅材料的一些建议     

提拉单晶炉自动引晶技术的研究

该文从人工引晶工艺流程入手,结合提拉法单晶炉已有技术和温度测控技术,使用计算机编程技术和传感器测量技术完成人工引晶的各项步骤,实现了提拉法单晶炉引晶技术的全自动化,从而实现真正意义上的全自动单晶炉。     

粒状多晶硅生产概况

阐述了粒状多晶硅生产的基本原理、生产工艺以及美国MEMCPasadena公司的粒状多晶硅的生产情况,并就粒状多晶硅生产过程中的质量控制措施、以粒状多晶硅为原料生产直拉单晶硅所具有的优势以及粒状多晶硅的发展前景提出了一些看法.     

Motion of etch defects on (0 0 1) Li2B4O7 single crystal wafer

Three types of etch defects were observed on a (0 0 1) lithium tetraborate (Li₂B₄O₇:LB4) single crystal wafer. Type I appeared all over the +c plane taking a four-sided pyramidal shape. The etch defects on the −c plane were differentiated into two types; Type II corresponded to dislocation arrays and presented a four-sided pyramidal shape while Type III was distributed all over the −c plane, forming a eight-sided hillock. After annealing the wafer at 850 °C in several different atmospheres, the density of Types I and II did not change while that of Type III was reduced by two order of magnitude in the oxygen atmosphere. This might suggest that the formation mechanism of each of these defects was different and they showed the various motions for the thermal treatment.