三牙轮钻头瓢形齿齿面结构的空间解析式及积分处理

本文以空间解析几何的数学理论,推导出了三牙轮钻头瓢形齿的横截面积、体积与瓢形齿吃入岩石深度之间的数学关系式,为研究钻头牙齿破碎岩石坑的形状大小提供了基准,也可作为三牙轮钻头工作行为计算机仿真研究的参考资料。     

固体氧化物燃料电池电极材料研究 Ⅱ.甲烷氧化转化阳极材料的制备与表征

制备了适合固体氧化物燃料电池中甲烷氧化转化的阳极材料Ni/La(Sr)MnO_3.利用差热分析和热重分析研究了该阳极材料的合成条件.应用电子探针、X射线衍射和扫描电镜分别对材料的组成和结构进行表征.对Ni/La(Sr)MnO_3的电导性能进行了研究,并与Ni/YSZ的电导性能进行比较,分析了影响阳板材料电导性能的主要因素.     

液氯钢瓶凹坑应力研究

通过液氯钢瓶凹坑应力测试,给出不同参数的凹坑应力分布,为液氯钢瓶判废标准提供依据.     

Seeded growth of AlN crystals on nonpolar seeds via physical vapor transport

Seeded growth of AlN single crystals was demonstrated in an induction-heated, high-temperature reactor via a physical vapor transport (PVT) process. AlN seeds were prepared from a self-seeded boule containing large single-crystalline grains. Seeded growth was interrupted several times in order to refill the AlN powder source, and a dedicated process scheme was used to ensure epitaxial growth on the seed surface, after prior exposure to air. The growth temperatures were in the range of 2200–2300°C, and the reactor pressure was in the range of 500–900 torr of UHP-grade nitrogen during each growth run. Under these growth conditions, a seed (10 mm diameter) expanded at an angle of 45°, and a larger single crystal up to 18 mm in diameter was obtained. The as-grown surface had three facets, of which facet (1120) was smooth and featureless while the other two, (4150) and (2570), showed serrated morphologies. The double-crystal x-ray rocking curve and glow discharge mass spectroscopy analysis confirmed that the grown crystal was of high crystalline quality with low impurity incorporation.     

MIMO Channel Characterization for Short Range Fixed Wireless Propagation Environments

This paper reports results from wideband MIMO measurements performed in short range fixed wireless environments at 5.2 GHz. The objective is to provide MIMO channel characterization results for the measured environments and contribute to the limited available similar studies. Two kinds of propagation scenarios are investigated, rooftop to rooftop and street to rooftop, at three different sites always under LOS propagation conditions. The analysis of measurement data is performed in the context of non physical modeling, providing insight into the statistics of the measured channels. In particular, the slow time varying nature of the channel is studied and the narrow Doppler spectrum shape is approximated. Furthermore, frequency correlation results are obtained and the typical delay dispersion measures are extracted. Then, the antenna correlation is studied and the error of the Kronecker product approximation is evaluated. Finally, capacity results are provided and the channel measurements are characterized in terms of spatial multiplexing quality and multipath richness through condition number analysis. Nikolaos D. Skentos received his Diploma in Electrical and Computer Engineering from the National Technical University of Athens (NTUA), Greece in October 2000. Since January 2001 he has been a research associate at the Mobile Radio Communications Laboratory at the NTUA, and he is currently working towards the Ph.D. degree. His research interests include channel measurements, MIMO channel characterization, MIMO algorithms and space time processing. He has been active in the IST STINGRAY project, the COST 273 Action and the ACE Network of Excellence. He is also a member of the National Technical Chamber of Greece since 2001. Athanasios G. Kanatas received the Diploma in Electrical Engineering from the National Technical University of Athens, Greece, in 1991, the M.Sc. degree in Satellite Communication Engineering from the University of Surrey, Surrey, UK in 1992, and the Ph.D. degree in Mobile Satellite Communications from the National Technical University of Athens, Greece in February 1997. From 1993 to 1994 he was with National Documentation Center of National Research Institute. In 1995 he joined SPACETEC Ltd. where he was Technical Project Manager for VISA/EMEA VSAT Project in Greece. In 1996 he joined the Mobile Radio Communications Laboratory as a research associate. From 1999 to 2002 he was with the Institute of Communication & Computer Systems. In 2000 he became a member of the Board of Directors of OTESAT S.A. He is an Assistant Professor in the Department of Technology Education and Digital Systems at University of Piraeus. His current research interests include channel characterization and estimation, simulation and modeling for mobile, mobile satellite, and future wireless communication systems. He has been a Senior Member of IEEE since 2002, and is also a member of the Technical Chamber of Greece. In 1999 he was elected Chairman of the Communications Society of the Greek IEEE Section. Panagiotis I. Dallas was born 1967 in Thessaloniki, Greece. He obtained his diploma and Ph.D. degree from the Electrical and Computer Engineering Department of Aristotle University of Thessaloniki, Greece, in 1990 and 1997, respectively. Since 1998 he joined with INTRACOM where he currently is Section Manager of Advanced Communications Technologies branch of Emerging Technologies & Markets department, leading the next generation of broadband wireless access systems for internal and EU projects. He runs the relevant standardization activities (IEEE 802.16 and ETSI/BRAN HIPERMAN) in INTRACOM and he represents the company in WiMAX forum. Finally, he has over 30 publications in international journals and conferences. Philip Constantinou received the Diploma in Physics from the National University of Athens in 1972, the Master of Applied Science in Electrical Engineering from the University of Ottawa, Ontario, Canada in 1976, and the Ph.D. degree in Electrical Engineering in 1983 from Carleton University, Ottawa, Ontario, Canada. From 1976 to 1979 he was with Telesat Canada as a Communications System Engineer. In 1980 he joined the Ministry of Communications in Ottawa, Canada where he was engaged in the area of Mobile Communication. From 1984 to 1989 he was with the National Research Center Demokritos in Athens, Greece where he was involved in several research projects in the area of Mobile Communications. In 1989 he joined the National Technical University of Athens where he is currently a Professor and Director of the Mobile Radio Communications Laboratory. His current research interests include Personal Communications, Mobile Satellite Communications, and Interference Problems on Digital Communications Systems.     

武汉阳光大厦地下室深基坑工程综合施工技术

以武汉阳光大厦工程为例,介绍了在复杂的工程地质、水文地质条件下,在汉口深厚软弱土层,典型的二元地质构造,复杂的周边环境条件并且有重要的临近基坑的公共建筑物的情况下,高层建筑深基坑工程支护结构体系设计与施工的方案选择、优化及实施过程,地下水治理设计与施工、土方开挖及信息施工等主要施工技术方法的运用情况,供类似工程施工参考.     

几种超氧化物歧化酶模型化合物的合成表征及活性测定

通过研究锰、铁超氧化物歧化酶活性部位的结构，以二（2－苯并咪唑亚甲基）胺（N3）为配体合成了两种单核超氧化物歧化酶的模型配合物，并以咪唑为桥合成了两种同双核及一种异双核模型配合物，对所合成的化合物进行了红外、紫外谱图的表征，最后利用邻苯三酚自氧化法检测了它们的生物活性。     

基坑支护中水土压力合算与分算的综合分析

分析了水土分算和水土合算的计算方法，并给出了在不同情况下水土分算的合理计算公式。提出了当采用不固结不排水强度指标时的土压力计算方法。通过将这些算法与实际工程的比较发现了“广义”水土合算法的不安全性，并找出了几种合理的算法。