(Fe_(0.86)Zr_(0.033)Nb_(0.033)B_(0.068)Cu_(0.01))_x(Al_2O_3)_(1-x)颗粒膜的霍耳效应

用磁控溅射方法制备了系列 (Fe0 .86 Zr0 .0 33Nb0 .0 33B0 .0 6 8Cu0 .0 1 ) x(Al2 O3) 1 -x颗粒膜样品 ,体积百分比x从 0 .3 3～ 0 .63 ,样品厚度约为10 0nm。室温下在Fe0 .86 Zr0 .0 33Nb0 .0 33B0 .0 6 8Cu0 .0 1 体积百分比x =0 .43时得到 17.5 μΩ·cm的最大饱和霍耳电阻率 ,比纯铁磁金属提高了 3～ 4个量级。对其磁性和微结构进行了研究 ,样品霍耳电阻率随外场的变化曲线 ρxy～H与磁场平行于膜面时的磁化曲线M～H有相似性 ,说明霍尔电阻率 ρxy与磁化强度M相关。样品电阻率 ρxx随金属体积百分比x的减小而增加 ,在x =0 .43附近发生突变 ,从金属导电变为绝缘体。根据微结构和输运性质对可能的机制进行了探讨     

交点计算的几种方法

在工程测量中，经常涉及到交点计算，如何运用现有的工具快速地计算出交点非常重要。本文介绍了利用控制器、AutoCAD绘图软件和Excel计算交点的方法，供大家参考。     

Effect of lanthanide ions on the phase behavior of dipalmitoylphosphatidylcholine multilamellar liposomes

The effect of lanthanide ions (Ln3+) and their coordination compounds of diethylenetriamine pentaacetic acid (DTPA) on the phase behavior of dipalmitoylphosphatidylcholine (DPPC) multi-lamellar liposomes has been studied by differential scanning calorimetry (DSC), Raman spectroscopy, and freeze-fracture electron microscopic techniques. The displacement of Ca2+ binding on DPPC liposomes by lanthanide ions was also studied. The results show that the binding degree of four kinds of chloride salts with DPPC liposomes is: YbCl3 > GdCl3 > LaCl3 > CaCl2. Lanthanide ions increase the phase transition temperature of DPPC liposomes and decrease the membrane fluidity. Freeze-fracture electron microscopic results show that La3+ enhances the order of DPPC membrane. The effect of coordination compounds of lanthanides with DTPA on the phase behavior of DPPC liposomes is smaller than that of their chlorides. La3+, Gd3+, and Yb3+, can displace Ca2+ binding on DPPC liposomes, but there coordination compounds of DTPA can hardly displace Ca2+. Raman spectroscopic results show that a very slight effect in lateral packing order of DPPC liposomes was observed at various concentrations of lanthanides.     

双辊式薄带连铸工艺研究

进行了双辊法薄带连铸的试验研究。阐述了双辊连铸机浇注系统的研究结果、工艺参数对连铸的影响，以及18—8不锈钢薄带坯的凝固组织和冷轧特性，该工作为薄带连铸的中间生产机组的研究奠定了基础。     

FHCF: A Simple and Efficient Scheduling Scheme for IEEE 802.11e Wireless LAN

The IEEE 802.11e medium access control (MAC) layer protocol is an emerging standard to support quality of service (QoS) in 802.11 wireless networks. Some recent work shows that the 802.11e hybrid coordination function (HCF) can improve significantly the QoS support in 802.11 networks. A simple HCF referenced scheduler has been proposed in the 802.11e which takes into account the QoS requirements of flows and allocates time to stations on the basis of the mean sending rate. As we show in this paper, this HCF referenced scheduling algorithm is only efficient and works well for flows with strict constant bit rate (CBR) characteristics. However, a lot of real-time applications, such as videoconferencing, have some variations in their packet sizes, sending rates or even have variable bit rate (VBR) characteristics. In this paper we propose FHCF, a simple and efficient scheduling algorithm for 802.11e that aims to be fair for both CBR and VBR flows. FHCF uses queue length estimations to tune its time allocation to mobile stations. We present analytical model evaluations and a set of simulations results, and provide performance comparisons with the 802.11e HCF referenced scheduler. Our performance study indicates that FHCF provides good fairness while supporting bandwidth and delay requirements for a large range of network loads. Pierre Ansel received a multidisciplinary in-depth scientific training in different fields such as Pure and Applied Mathematics, Physics, Mechanics, Computer Science and Economics from the Ecole Polytechnique, Palaiseau, France. Then, he joined the Ecole Nationale Superieure des Telecommunications, Paris, France in 2005 where he went further into electronics, databases, computer network security and high speed networks. He received a multidisciplinary master of sciences degree and an additional master of sciences degree in telecommunications in 2005. He did a summer internship in 2003 in INRIA, Sophia Antipolis, France where he worked on the Quality of Service in 802.11 networks at Planete Group, France. Then in 2004, he joined France Telecom R&D, Issy-les-Moulineaux, France to work on Intranet Security issues. He designed a WiFi security supervision architecture based on WiFi Intrusion Detection Sensors. He is currently a French civil servant and belongs to the French Telecommunications Corps. Qiang Ni received the B.Eng., M.Sc. and Ph.D. degrees from Hua Zhong University of Science and Technology (HUST), Wuhan City, China in 1993, 1996 and 1999 respectively. He is currently a faculty member in the Electronic and Computer Engineering Division,School of Engineering and Design, Brunel University, West London, U.K. Between 2004 and 2005 he was a Senior Researcher at the Hamilton Institute, National University of Ireland, Maynooth. From 1999 to 2001, he was a post-doctoral research fellow in the multimedia and wireless communication laboratory, HUST, China. He visited and conducted research at the wireless and networking group of Microsoft Research Asia Lab during the year of 2000. From Sept. 2001 until may 2004, he was a research staff member at the Planète group of INRIA Sophia Antipolis France. Since 2002, he has been active as a voting member at the IEEE 802.11 wireless LAN standard working group. His current research interests include communication protocol design and performance analysis for wireless networks, cross-layer optimizations, vertical handover and mobility management in mobile wireless networks, and adaptive multimedia transmission over hybrid wired/wireless networks. He has authored /co-authored over 40 international journal/conference papers, book chapters, and standard drafts in this field. He is a member of IEEE. E-mail: Qiang.Ni@ieee.org Thierry Turletti received the M.S. (1990) and the Ph.D. (1995) degrees in computer science both from the University of Nice – Sophia Antipolis, France. He has done his PhD studies in the RODEO group at INRIA Sophia Antipolis. During the year 1995–96, he was a postdoctoral fellow in the Telemedia, Networks and Systems group at LCS, MIT. He is currently a research scientist at the Planete group at INRIA Sophia Antipolis. His research interests include multimedia applications, congestion control and wireless networking. Dr. Turletti currently serves on the Editorial Board of Wireless Communications and Mobile Computing.     

Influence of Zirconium Addition on Magnetic Properties and Temperature Coefficient for Nanocomposite Nd10Fe78.5-xCo5ZrxB6.5 Magnets

The influence of Zr addition on magnetic properties and temperature coefficient for nanocomposite Nd10Fe78.5-xCO5ZrxB6.5 (x=0~4) bonded magnets was investigated. It was found that the room-temperature magnetic properties were remarkably improved with Zr addition due to the grain refinement and increasing volume fraction of the hard magnetic phase. The optimal magnetic properties of Jr=0.689T, iHc=769.4kA·m-1 and (BH)max=84kJ·m-3 were obtained for 2.5% Zr addition. The temperature coefficient of remanence (α) increases slightly and the temperature coefficient of coercivity (β) decreases obviously with increasing Zr content for nanocomposite Nd10Fe78.5-xCo5ZrxB6.5 (x=0~4) bonded magnets.     

无氢类金刚石碳膜的研究进展

介绍了无氢类金刚石碳膜的制备方法 ,它们的机械、光学、电学性能 ,将无氢与含氢的类金刚石碳膜进行了简单比较 ,总结及探讨了它们的应用     

Efficiency of sediment transport by flood and its control in the Lower Yellow River

1IntroductionIntheriversystemwithsediment-ladenflow,WaterUseforSedimentTransport(WUST)isaveryimportantcomponentofecologicalwaterdemands,whichmaintainfundamentalfunctionofallecosystemcomponentsataspecificlevelofcondition[1].EnoughWUSTisthepremisetokeepthestableriver-bedandhealthyriverecosystem;alsoitisthebaseflowofriverfortheexploitationofwaterresources.Comparingwithotherrespectsrelatedwithwaterdemandsofriverecosystemsuchastheminimumflowforfishesorripariantrees,researchesontheWUSTarequite…     

光源与物体色显现关系的仿真技术探讨

本文提出一种“利用原色漂移量调整法”确定当物体光谱反射率未知时光源与物体色显色关系。 利用该关系，通过微机真彩色数字图象技术对光环境进行仿真模拟。