Controlled Synthesis of Metal Nanocrystals and Their Related Catalytic Properties

金属纳米材料因为其独特的物理化学性质而被广泛应用于催化、生物医学、传感器等领域。最近的研究表明，金属纳米材料的性质与其结构（包括尺寸和形貌）密切相关。尤其是在催化应用上，金属纳米催化剂的结构特点决定了其在催化反应中的活性和选择性。以炔烃还原制备烯烃这个反应为例，金属钯纳米催化剂的尺寸和形貌决定了反应过程中炔烃的转化率和选择性。因此到目前为止在金属纳米材料的研究这个课题上的重点依然是对其尺寸和形貌的调控，即金属纳米材料的可控合成。 本博士论文主要围绕三大研究方向进行：（1）贵金属纳米颗粒的可控合成及其形貌和性能间联系的研究；（2）金属铜纳米材料的可控合成及结构表征；（3）钯铂双金属纳米结构的构...Metal nanocrystals have been actively explored in recent years due to their unique properties and applications related to catalysis, biomedical, and sensors. Like other systems, the properties of metal nanocrystals are strongly dependent on both size and shape, especially when used as catalysts. Take the hydrogenation of alkynes for example; the conversion efficiency and selectivity of alkynes to ...学位：理学博士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：2052006015323

Growth of High-reflectivity AlN/GaN Distributed Bragg Reflectors in Blue Region

采用金属有机物化学气相沉积方法制备了蓝光波段高反射率Aln/gAn分布布拉格(dbr)反射镜。利用金相显微镜、扫描电子显微镜、原子力显微镜以及分光光度计等测量手段对样品的物理特性进行了分析表征。结果显示样品的表面有少量圆形台面结构和裂纹出现,但在其他区域,样品具有较为平整的表面。该样品在462.5 nM附近获得最大反射率99.4%,表面均方根粗糙度小至2.5 nM。分析表明,所得dbr达到了制备gAn基垂直腔面发射激光器的要求。One high-reflectivity AlN/GaN distributed Bragg reflector(DBR) in blue region was grown with the method of metalorganic chemical vapor deposition(MOCVD).perties of the sample were analyzed by using,scanning electron microscope(SEM),atomic force microscopy(AFM) and spectrophotometer.Except for the circular mesa structure and a few cracks observed on the surface,the sample showed a rather smooth surface.A peak reflectivity of 99.4% was observed around 462.5 nm and the surface roughness was as small as 2.5nm.The properties of the DBR meet the requirements of GaN-based vertical cavity surface emitting lasers(VCSEL).国家“863”计划资助项目(2006AA03Z409

高指数晶面裸露的贵金属纳米晶体的合成

由于在高指数晶面上存在高密度的台阶位、扭结位原子等,高指数晶面裸露的贵金属纳米晶体一般表现出优越的物理化学性能,在催化、电化学等方面都有很重要的应用前景.近年来,研究人员围绕高指数晶面的制备进行了大量的工作并取得了一定进展.本文重点从合成制备方法的角度出发,结合本课题组的相关研究,系统总结了现有的有关制备高指数晶面裸露的贵金属纳米晶体的一些最新研究成果.从电化学方法、"帽"式试剂保护法、欠电位沉积原子层保护法、动力学调控、氧化刻蚀溶解再生长法以及模板法等几个方面对现有的高指数晶面裸露的贵金属纳米晶体的制备进行了总结

Weathering process of granitic rocks in Sør-Rondane Mountains, East Antarctica

第7回極域科学シンポジウム:[OG] 地圏11月29日（火）国立極地研究所 1階 交流アトリウ

ESRとグラニュー糖を利用した放射線量の測定(I)

This study evaluated ESR radiation dosimetry using granulated sugar. One gram of granulated sugar was irradiated by X-ray radiation under conditions : tube voltage, 60kVp ; tube current, 3mA ; dose rate, 8Gy/min ; and FSD, 7.5cm. After irradiation, the granulated sugar was placed in a quartz sample tube with inner diameter 4.0mm. Then, ESR specteometry was carried out under the conditions : center field, 336mT ; power, 10mW ; sweep width, ±5×10mT ; modulation width, 0.5×0.1mT ; receiver gain, 2×100 ; time constant, 0.1sec ; and sweep time, 4min. Detection and measurements were made at doses of 0, 8, 16, 32, 64, 128, and 160Gy. The results showed that the irradiated granulated sugar produced free radicals and the signal intensities were dose dependent without fading. These findings confirm that ESR radiation dosimetry using granulated sugar would enable estimates of radiation therapy doses