High catalytic activity of PdOx/MnO2 for CO oxidation and importance of oxidation state of Mn

PdO_x/MnO₂ has been examined as a catalyst for CO oxidation using a conventional flow reactor at reaction temperatures between 50 and 150°C. In the reaction conditions of GHSV (gashourlyspacevelocity) of 1.22 × 10⁵/h and CO concentration of 2000 ppm, PdO_x/MnO₂ showed higher catalytic activity compared with PdO_x/Mn₂O₃, which had been previously reported as an effective catalyst due to the cooperative action of Pd and Mn₂O₃ for this reaction. The reason for higher activity of PdO_x/MnO₂ than PdO_x/Mn₂O₃ has been investigated using TPR (temperatureprogrammed reduction) and XPS studies. TPR showed that PdO_x/MnO₂ could be reduced by CO at much lower temperature than PdO_x/Mn₂O₃. During the experiment of reduction and oxidation, XPS showed that the valence of Mn in the PdO_x/MnO₂ was between 4+ and 3+, which is higher than that of Mn in the PdO_x/Mn₂O₃ catalyst of which the valence has been reported to be between 3+ and 2+. It is known that in this catalyst system the support supplies oxygen onto Pd, where the oxidation occurs with adsorbed CO, and the ability of the support to provide oxygen improves the performance of the catalyst. Therefore, it was concluded that the readiness of MnO₂ to be reduced with maintaining a higher oxidation state showed higher CO oxidation activity than Mn₂O₃ as support for PdO_x.     

Nanocrystalline CeO2 in SBA-15: Performance of Pt/CeO2/SBA-15 Catalyst for Water-gas-shift Reaction

CeO₂ particles confined within the pores of an SBA-15 mesoporous silica host were prepared by incipient wetness impregnation (IMP) and deposition precipitation (DP) methods. The materials were characterized by XRD, N₂-adsorption and temperature programmed reduction (TPR) to evaluate the structure, texture, and redox properties. The preparation procedure had significant impact on the assembling mode of CeO₂ inside the SBA-15 mesopores. A high dispersion of CeO₂ particles was achieved via DP, whereas the dispersion of CeO₂ prepared by IMP was found to be inhomogeneous and CeO₂ partially blocked the pores. The CO conversion in the water-gas-shift reaction was enhanced over 1 wt% Pt supported on CeO₂-modified SBA-15 obtained by DP.     

火焰原子吸收光谱法测定硅粉中的铜

介绍了用火焰原子吸收法测定工业硅粉中微量铜的具体方法和过程，同时也给出了最佳实验条件。实验中采用新的样品处理方法，得到了令人满意的结果。其中样品回收率为99．8％—104．0%，相对标准偏差为0．31％—0.38％。本方法在实际应用过程中，简单、快速、     

钛酸铝材料性能及合成工艺

着重介绍了钛酸铝（Al2TiO3）陶瓷的结构、性能和合成工艺，并对今后发展趋势提出了基本观点。     

Study of different effect on foaming process of biodegradable bionolle in supercritical carbon dioxide

Microcellular foaming of biodegradable Bionolle in supercritical CO₂ has been produced. The effects of a series of variable factors, such as saturation temperature, saturation pressure, and depressurization time and step on the foam structures and density, were studied through measurement of density and SEM observation. The experimental results show that higher saturation temperatures lead to an increase in bulk densities; and different depressurization time and step result in different product cell morphology. In addition, at some saturation temperature, the orientation of the cells can be found in the product morphology. XRD experimental results show that the foaming treatment with SC CO₂ increased the crystallinity of Bionolle. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2901–2906, 2006     

Solid state interfacial reactions in electrodeposited Ni/Sn couples

Ni/Sn couples,prepared by sequentially electroplating Ni layers and Sn layers on metallized Si wafers,were employed to study the mierostructures and growth kinetics of Ni-Sn intermediate phases,when the Ni/Sn couples were aged at room temperature or annealed at temperatures from 150 to 225℃for various times.The results show that the NiSn phase and Ni_3Sn_4 phase are formed,respectively,in the aged couples and annealed couples.The Ni_3Sn_4 layer is continuously distributed between the Ni and Sn sides in t...     

Moodle在中澳合作办学项目中的应用

Moodle以其经济性和易用性等特点,已在教育领域中得到广泛应用。浙江科技学院在中澳合作办学项目中,基于Moodle的网络教学平台成了联系中澳双方的纽带,为双方教师及学生参与各种教学活动提供了有效的途径。在分析了Moodle课程管理系统的特点和主要功能模块之后,介绍了Moodle在项目中的实际应用情况,指出了在使用这个教学平台过程中存在的不足。     

强化两相混合的超临界技术制备聚乳酸微粒

针对商品化聚乳酸微球粒径分布较宽难于适用气溶胶给药要求的不足,采用水力空化混合强化超临界流体辅助雾化技术(SAA-HCM)制备聚乳酸(PLA)超细微粒.该技术主要特点是通过在超临界流体和液相进料处引入水力空化混合器,强化两相间的混合.考察SAA-HCM过程混合器压力、温度、沉淀器温度、进料中CO2与液体溶液质量流量比和溶液质量浓度等操作参数对微粒形态和粒径分布的影响,成功制备出球形度较好,粒径分布较窄(1～3μm)的PLA微球.经X射线衍射(XRD)分析和差示扫描量热(DSC)分析显示,与原料PLA相比,微球晶型及热曲线变化不大,但结晶度下降.同时把操作参数与相行为进行关联,探讨了影响颗粒形貌的机理.对比超临界流体辅助雾化法(SAA)的实验结果表明:水力空化的引入能有效强化混合器内的两相传质,混合更好,能制备出适用于气溶胶给药要求的超细微粒.     

AADL 测试模型的构造研究

目前,结构分析和设计语言AADL在任务关键嵌入式系统领域有着良好的应用.为了保障任务关键软件的质量,文章提出基于AADL测试模型对AADL设计模型进行测试,以发现设计模型中存在的错误.研究给出了体现系统拓扑结构的AADL测试模型的形式定义及由AADL构造该测试模型的算法,基于该测试模型可以对AADL设计模型中构件交互的输入、输出端口序列和连接的正确性进行测试,并以飞行控制系统的AADL设计模型为例,阐释了研究成果.     

仿土质专用肥的开发和应用前景

本文介绍了基于某些名、优农产品在其生长过程中所需要的特定敏感元素,配制出“仿土质”专用肥。经施用证明,肥效显著,经济效益可观,具有推广应用的前景。