新型磁阻传感器测量地磁场实验的教学探讨

探讨了一种新型磁阻传感器在测量地磁场方面的应用。特别在确定地磁子午面方向和测量磁倾角上,提出了新的实验方法。该方法具有操作简单,精确度高等优点。在实验中,学生能够容易掌握关键操作要点,取得了不错的实验教学成果。     

微型化频率选择表面的设计研究

利用容性表面与感性表面之间的耦合机理能够制备微型化频率选择表面(MEFSS),周期单元尺寸将不受工作波长限制.为了提高MEFSS角度与极化的稳定性,展宽MEFSS的-3 dB带宽,文章结合传统频率选择表面"Y"形单元,利用"Y"图形构造容性表面的贴片单元与感性表面的网栅单元且以正三角形栅格拓展周期单元,采用矢量模匹配法对MEFSS栅格排布及其他结构参数变化进行精确计算.通过镀膜与光刻技术在0.15 mm厚聚酰亚胺膜两侧制备容性表面、感性表面并利用自由空间法测试.计算与实验结果均表明,采用正三角形栅格排布的MEFSS,-3 dB带宽达到7.6 GHz,不同极化下60°扫描时中心频点稳定在f₀,为MEFSS应用于曲面天线罩时提供理论与实验参考依据. 关键词： 天线罩 微型化频率选择表面 容性表面 感性表面     

NON-CONFLICTING ORDERING CONES AND VECTOR OPTIMIZATION IN INDUCTIVE LIMITS

Let(E, ξ) = ind(En, ξn) be an inductive limit of a sequence(En, ξn)n∈N of locally convex spaces and let every step(En, ξn) be endowed with a partial order by a pointed convex(solid) cone Sn. In the framework of inductive limits of partially ordered locally convex spaces,the notions of lastingly efficient points, lastingly weakly efficient points and lastingly globally properly efficient points are introduced. For several ordering cones, the notion of non-conflict is introduced. Under the requirement that the sequence(Sn)n∈N of ordering cones is nonconflicting, an existence theorem on lastingly weakly efficient points is presented. From this,an existence theorem on lastingly globally properly efficient points is deduced.     

尿素熔体中镧钴电解共沉积的研究

采用循环伏安曲线，电子探针，Ｘ射线衍射法，研究了尿素－ＮａＣｌ－ＮａＡｃ－ＣｏＣｌ２－ＬａＣｌ３熔体中镧钴电解共沉积，阴极电位，电流密度，熔体中Ｌａ＾３＋／Ｃｏ＾２＋摩尔比以及电极基体均影响沉积物中的含镧量。沉积物由Ｃｏ和Ｌａ组成，两者并末形成金属间化合物。     

多光感应测量仪

利用电子技术制作了多光感应测量仪，实现了物体运动起始计时和连续测量时间的要求。     

同轴电缆抗电磁干扰性能实验

利用自制实验装置，研究了同轴电缆的电容耦合频率特性、电容耦合屏蔽效果、电感耦合屏蔽效果．     

Elementarity and Dimensions

An alternative proof of Fedorchuk’s recent result that dim X ≤ Dg X for compact Hausdorff spaces X is given. The problem is reduced to the metric case by using the Lowenheim-Skolem theorem.__________Translated from Matematicheskie Zametki, vol. 78, no. 2, 2005, pp. 292–298.Original Russian Text Copyright © 2005 by K. P. Hart.     

Investigation of Different Input-Matching Mechanisms Used in Wide-Band LNA Design

This paper analyzes different input-matching mechanisms used in designing the wide-band amplifiers in general, and the low noise amplifiers (LNA) in particular, and their corresponding noise impact. Among them, the most promising one is the reactive-feedback circuit configuration, which is a combination of high-frequency inductive feedback and low frequency capacitive feedback. In this paper the simulated result that both matched input impedance and low noise temperature T_n can be achieved simultaneously over a wide bandwidth in the single-ended low noise amplifier is proved mathematically and is well interpreted. This understanding of reactive feedback is crucial for the future development of ultra-wide-band low-noise amplifiers.     

Sequentially Complete Inductive Limits and Regularity

A notion of an almost regular inductive limits is introduced. Every sequentially complete inductive limit of arbitrary locally convex spaces is almost regular.