Study on the dispersion characteristic of the plasma-loaded relativistic BWO

The dispersion characteristic of the plasma-loaded relativistic backward wave oscillator has been analyzed. The theoretical model has been established and the numerical calculations accord with the experimental results, which provides some useful suggestions on the designing of slow-wave structure of BWO.     

Al,Ga取代Bi：DyIG薄膜的磁和磁光特性的研究

本文报道用热分解法在玻璃衬底上制备了Ａｌ和Ｇａ取代的Ｂｉ：ＤＹＩＧ薄膜，对其磁和磁光特性做了详细研究．Ａｌ和Ｇａ取代的薄膜均可获得好的矩形比和高的矫顽力．对于Ｂｉ１．２Ｄｙ１．８Ｆｅ５－ｘＭＸＯ１２（Ｍ＝Ａ１，ＧＺ）薄膜，Ａ１和Ｇ２的最佳替代成份分别为１．０和Ｇ．７；最佳晶化温度分别为７００ｏ℃和６７５℃．在波长５１０ｎｍ附近，法拉第旋转角可达８°／ｕｍ左右．光学吸收和品质因子的研究结果表明，Ａｌ和Ｇａ取代能够影响光学吸收和品质因子，其中Ｇａ取代对光学吸收和品质因子的影响较大．     

Preparation of Metal-Coated Carbon Fiber Reinforced Composites and Their Electromagnetic Properties

Medium temperature curing by infrared radiation was used to prepare electromagnetic wave absorbing multilayered plastic matrix composite materials containing metal-coated carbon fibers (MCFs). The electromagnetic properties of the materials were investigated by frequency scanning tests with microwave vector network analyzer. It is found that the electromagnetic parameters, mainly permittivity of the composites increase significantly with the addition of MCFs, which gives the composites good designability as thin, light-weight EM wave absorbers. It is also shown that MCFs can improve on the EM wave energy attenuating property of the composites by widening the work frequency band width and raising the absorptive peak     

西北江三角洲来水来沙的非线性分形特征

根据西、北江干流高要、石角及西北江三角洲网河区顶点马口、三水四个水文站的流量和含沙量资料 ,应用非线性分形原理的R S方法 ,计算西北江干流及西北江网河区顶点四个水文站的流量、含沙量的赫斯特数H和分形维数D ;探讨西、北江干流来水来沙的分形特征及西北江三角洲的分水分沙规律。结果表明 ,流量的分维数略大于含沙量的分维数 ,三水站流量及含沙量的分维数与其上游的石角站流量、含沙量的分维数相差较大 ,与思贤的分水分沙造成西北江的水沙交换有关     

化学锚固在结构改造加固中的应用

随着钢筋混凝土结构技术的日趋成熟,一项新兴的技术逐渐被人们认同和重视,即钢筋混凝土结构改造中的化学锚固技术。早在20世纪六七十年代,发达国家已经研制出利用化学栓剂,将螺栓、钢筋种植在混凝土结构中,特别是对于既有混凝土结构改造及加固起到了决定性的作用。随着改革开放,这项技术在我国也逐步得到了运用。1各种结构胶在工程中的应用结构胶的应用范围非常广泛,就锚固来讲,解决了新旧混凝土之间钢筋连接及新旧结构间应力的传递。如某博物馆结构改造中原结构为框架结构,始建于20世纪50年代末期,经鉴定不符合烈度为8度的抗震要求,现将其…     

攀钢含铁尘泥的利用现状及发展方向

简述了攀钢含铁尘泥的基本特性、攀钢含铁尘泥利用技术现状及存在的问题。根据目前国内外钢铁企业含铁尘泥综合利用技术的动态、经验，并结合攀钢的实际情况，提出了攀钢含铁尘泥利用技术的发展方向。     

利用非线性自适应技术检测微弱的瞬时信号

本文根据局部流形理论,提出了一类非线性自适应预测滤波模型。仿真结果显示,本文提出的自适应预测滤波模型具有很强的非线性近似能力,可以检测淹没在超混沌或杂波环境中的瞬时信号。     

Design and analysis of a plug-in robust compensator: an application to indirect-field-oriented-control induction machine drives

It is well known that the system performance for an indirect-field-oriented-control induction motor drive degrades under the variation of rotor resistance and in the presence of external load torque. In this paper, a plug-in robust compensator for speed and position control enhancement of an indirect-field-oriented-control induction machine drive is developed. In the case where a controller for the induction machine already exists or is in operation with satisfactory nominal tracking performance, this plug-in compensator, designed using the H/sub /spl infin// loop-shaping techniques, can be plugged into the existing controller without affecting the already satisfactory nominal tracking performance of the existing closed-loop system but with the capability to improve the system performance under plant parameter variations and in the presence of external disturbances. Simulation and experimental results are given to validate the proposed plug-in robust compensator.     

立方相GaN的持续光电导

研究了金属有机物化学气相外延 (MOVPE)方法生长的非故意掺杂的立方相 Ga N的持续光电导效应 .在六方相 Ga N中普遍认为持续光电导效应与黄光发射有关 ,而实验则显示在立方 Ga N中 ,持续光电导效应与其中的六方相 Ga N夹杂有关系 ,而与黄光发射没有关系 .文中提出 ,立方相 Ga N与其中的六方相 Ga N夹杂之间的势垒引起的空间载流子分离是导致持续光电导现象的物理原因 .通过建立势垒限制复合模型 ,解释了立方相 Ga N的持续光电导现象的物理过程 ,并对光电导衰减过程的动力学作了分析 .对实验数据拟合的结果证明以上的模型和推导是与实验相符的 .