新型磁致伸缩材料FeGa合金研究进展

作为一种新型的功能材料,FeGa合金磁致伸缩材料以其饱和磁致伸缩系数高、饱和场小、机械性能优良、成本低等优点,在诸多领域具有潜在的应用价值,已成为当前该领域科研工作者的热点研究问题之一。主要介绍了近年来在FeGa合金磁致伸缩材料方面的最新研究进展,重点从制备方法、合金成分及后期热处理等方面阐述了提高FeGa合金磁致伸缩材料性能的方法,最后对目前FeGa合金材料存在的问题和发展趋势进行了分析和展望。     

超磁致伸缩致动器的磁-机械强耦合模型

稀土一铁超磁致伸缩材料作为一种新型功能材料，其应用越来越受到人们的关注。为了有效地设计、开发超磁致伸缩材料的器件，必须建立材料器件的输入输出模型。利用能量变分原理，针对研制的超磁致伸缩致动器，建立了系统的磁一机械强耦合模型，并应用有限元法计算了致动器的输入电流与输出位移的关系曲线。计算值与实验值比较吻合，表明所建立的模型能够反映致动器的输入输出关系，模型对于设计超磁致伸缩器件、优化设计方案具有重要意义。     

稀土超磁致伸缩电机及其应用

稀土超磁致伸缩电机在大应变、强力和高功率密度及高精度、快速响应以及高可靠性等方面有着其它电机无法比拟的优点。介绍了这种电机的结构原理、性能特点及其典型应用事例。文中还就稀土超磁致伸缩材料及其驱动器件的市场应用前景进行了展望。     

超磁致伸缩薄膜致动器磁-机械特性研究

超磁致伸缩材料以其高能量输出、高操作频率、远程非接触式控制等特点广泛应用于各种微机械系统中.建立了超磁致伸缩薄膜型致动器的磁-机械强耦合模型,并且进行了理论及数值推导.薄膜尺寸只有几微米,有限元方法在进行单元剖分时会产生严重的网络变形,从而降低计算精度.提出采用无单元Galerkin方法来进行数值计算,比较了计算值和实验值,吻合情况较好.     

磁光材料的典型效应及其应用

磁光材料是一类品种繁多、应用广泛的重要的功能材料.近年来,随着激光、计算机、信息、光纤通信等技术的发展,各种磁光材料--磁光玻璃、磁光薄膜、磁性液体、磁性光子晶体和磁光液晶等发展极为迅速.本文简介了磁光效应(包括法拉第效应、克尔效应、塞曼效应和磁致双折射效应等)的基本理论以及各种磁光材料和磁光器件的研究新进展.     

超磁致伸缩材料及其在电动机中的应用

超磁致伸缩材料（Giant Magnetostrictive Material简称GMM）是近年来发展起来的一种新型功能材料，在国内外得到广泛应用。将超磁致伸缩材料在电机中的应用技术已经比较成熟。简要介绍了超磁致伸缩材料以及在电机中的应用举例，还对研制一种新型电机-压电陶瓷-磁致伸缩电机进行了展望。     

稀土超磁致伸缩材料及其应用研究现状

近些年发展起来的一种新型磁功能材料——稀土超磁致伸缩材料,显示出了广阔的发展前景。着重介绍了超磁致伸缩材料的基本特性和国内外发展近况以及在军事和海洋探索方面的应用。     

磁致伸缩换能器材料的物理特性

用磁性物理的理论解释了磁致伸缩的产生机制,分析了磁致伸缩材料在磁化过程中的物理特性,指出了使用磁致伸缩换能器的物理条件。文末还介绍了磁致伸缩换能器材料的最新发展动态。     

磁致伸缩材料及其在机械工程中的应用

简要综述了国内外磁致伸缩材料的研究战果,并探讨了磁致伸缩材料在机械工程中的应用。     

稀土巨磁致伸缩材料及其在低压电器中的应用

稀土巨磁致伸缩材料是在磁场的作用下能产生巨大伸缩形变的一种新型功能材料。本文对此材料作了简要的介绍后，重点介绍了它在低压电器中的应用及其在器件设计中应注意的问题。     

薄膜锂电池制备工艺现状

随着无线电通讯和集成光电路的迅速发展 ,在很多电子设备上都要求有独立的高性能微型电源。薄膜锂电池作为一种重要的微型能源形式 ,正在受到越来越多的关注和研究。概述了国际上目前制备薄膜锂电池的阴极膜、阳极膜和电解质膜过程中所采用的各种工艺手段 ,从工作原理、采用的材料与设备、得到的膜的物理化学性能等各个方面对这些工艺方法进行了分析、比较及评价     

Characteristics of lithium niobate based capacitors and transistors

Abstract

The electrical properties of thin film (<1000 Å) capacitor devices of lithium niobate grown on silicon and platinum and of thicker film metal-ferroelectric-semiconductor field effect transistors (MFSFET) with lithium niobate as the gate material were measured. Dielectric constants of the thin films on silicon were as high as 27, while those for films on platinum were as high as 49. The MFSFET structures showed good FET properties, and demonstrated a channel current modulation consistent with switching of the ferroelectric gate by pulsing.     

基于GaN FETs的高频半桥谐振变换器分析与设计

随着Si材料半导体器件性能逐步达到瓶颈,宽禁带半导体器件(GaN、SiC)在诸多方面展现出了很好的性能,如低导通阻抗,小输入、输出电容等,这些特性使得GaN和SiC器件能够应用在更高的开关频率条件,从而提高系统的功率密度。针对基于GaN FETs构成的高频半桥谐振变换器进行设计,分析了高频条件下寄生电感参数对系统驱动电压及漏源极电压的影响,同时分析了高频条件下系统电压电流测量所需注意的事项及影响因素,为高频条件下GaN FETs的应用提供一定的帮助。     

超磁致伸缩器件的数值计算模型

为了分析超磁致伸缩器件中的磁机械耦合问题,提出了一个非线性有限元模型,它是建立在能量变分基础上的。在处理磁机械耦合问题时采用了弱耦合解法。该有限元模型的特点是考虑了弹性模量随磁场的变化。用这个模型计算了一组用不同方法制备的超磁致伸缩材料ＴｅｒｆｅｎｏｌＤ的饱和磁致伸缩量值,并与测试结果作了比较,从而证实了这个模型的正确性。     

Development of Materials Integration Strategies for Electroceramic Film-Based Devices Via Complementary In Situ and Ex Situ Studies of Film Growth and Interface Processes

We review our studies of film growth and interface processes performed using complementary in situ and ex situ characterization techniques that provide valuable information critical to the development of materials integration strategies for the fabrication of electroceramic film-based devices. Specifically, we review our work performed using in situ time-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) / X-ray photoemission spectroscopy (XPS) / spectroscopic ellipsometry (SE), in conjunction with ex situ TEM and other techniques to study film growth and interface processes critical to the fabrication of non-volatile ferroelectric memories (NVFRAMs), dynamic random access memories (DRAMs), and high frequency devices based on high-K thin films. TOF-ISARS involves three distinct but closely related experimental methods, namely: ion scattering spectroscopy, direct recoil spectroscopy and mass spectroscopy of recoiled ions, which provide monolayer-specific information on film growth and surface segregation processes. Spectroscopic Ellipsometry enables investigation of buried interfaces. XPS provides valuable information on the chemistry of surface and interfaces. Specifically, we discuss: a) studies of oxidation of Ti-Al layers and synthesis and properties of La 0.5 Sr 0.5 CoO 9 /Ti-Al heterostructured layers for integration of PZT capacitors with Si substrates, and b) studies of BaSr x Ti 1 m x O 3 layer integration with Si substrates relevant to DRAMs, high frequency devices and high-K gate oxides for integrated circuits. This review shows the power of combined in situ / ex situ analytical techniques to provide valuable information for material integration strategies for electroceramic thin film-based devices.     

Dielectric surface flashover in vacuum. Experimental design issues

In order to determine the influence of intrinsic material properties of dielectric materials on high field surface flashover characteristics in vacuum, it is important that we minimize or eliminate the influence of the experimental test structure on the high field processes. In this paper we shall examine the flashover characteristics of polycrystalline alumina insulators, using a lateral test structure similar to the one used in semiconductor devices. A significant improvement in surface flashover strengths (~200%) was found using a metalized contact electrode system compared with a classical solid electrode system. The results indicate that, using a metalized film cathode, the scatter in the flashover data is significantly reduced compared with the solid electrode system, implying that the electron-dielectric interaction processes that lead to flashover occur in a more predictable fashion. The new metal contact electrode system reveals the dependence of flashover strength on the surface preparation and the grain size of the dielectric material. The average flashover strength increases and the scatter in the flashover data decrease with a decrease in the average grain size of the particles composing the alumina ceramic. Thus the surface flashover processes in vacuum are related to the dielectric surface microstructure, specifically the surface and sub-surface microdamage and grain-boundary defects     

现场可编程门阵列在开关设备在线监测中的应用

利用现场可编程门阵列可靠性高、通用性强、可重构等优点,设计出用于开关设备状态在线监测的专用芯片。该芯片集采集、计量、通讯、报警功能于一体,配以少量的外围器件,便可实时监测开关设备的温度、机械、绝缘等各项状态参数。该芯片具有通用的通讯接口,可以与上位机通讯。与以往使用单片机实现开关设备状态在线监测的设计方案相比,该设计具有可重构、速度快、灵活性高的特点。     

含金属氧化物添加剂的AgNi电触头材料研究

采用独特方法与粉末冶金法相结合的方式制备了含金属氧化物(MeO)添加剂的AgNi电触头材料,并对材料的相结构、添加剂的分布均匀性、金相组织、力学物理性能、电气应用性能等进行了分析、研究。结果表明,MeO添加剂的加入提高了AgNi电触头材料的电寿命,且其力学物理性能没有明显下降,适用于中等电流等级的接触器等低压电器中。     

Comparison with film substrates of polyimide and Ni for cantilevered magnetic actuators

This paper describes a cantilevered actuator driven by magnetostriction in a low magnetic field. The dimensions of the two‐layer actuator were 1 mm × 5 mm, and amorphous FeSiB was used as the positive magnetostrictive material. The theoretical formulas for the amount of displacement and force of the actuator were obtained. In the experiment, a nonmagnetic polyimide film material and a negative magnetostrictive Ni film material were used as the substrates. The change in the characteristics of the actuator caused by changing the substrate was examined with theoretical formulas and experiments. It is shown that the actuator with Ni as the substrate was designed to obtain the largest displacement and the largest force. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.