平面电磁波性质的推导与讨论

简洁推导平面电磁波的基本关系式并由此讨论平面电磁波的性质．     

多普功效应演示器

通过一系列电路，使电磁波的多普勒效应直观显示。可用于课堂教学及相应领域。     

Normal mode wave-number estimation using horizontal synthetic aperture array

A moving synthetic aperture processing with high resolution spectral analysis method was provided to estimate the mode wave-number of acoustics in shallow water waveg- uide, and to overcome the problem of short aperture. First, large aperture synthetic array is created by a moving of short horizontal array, then a MUSIC processing is applied to the estimation of normal mode wave-number. The simulated and sea trial results indicate that the problem of short aperture can be resolved by using of synthetic aperture processing, and the accuracy of estimation in normal mode wave-number could be improved by varying the array depth when it is being towed away from the source.     

A partial order in the knot table II

A partial order on the set of the prime knots can be defined by the existence of a surjective homomorphism between knot groups. In the previous paper, we determined the partial order in the knot table. In this paper, we prove that 31 and 41 are minimal elements. Further, we study which surjection a pair of a periodic knot and its quotient knot induces, and which surjection a degree one map can induce.     

电磁波在全反射时的周相变化

本文由电磁场理论得出：电磁波在两介质交界面上发生全反射时，反射波电矢量的两个分量Ｅ⊥＇和Ｅ∥＇在周相上都超前于入射波电矢量的相应分量，而且Ｅ∥＇超前于Ｅ⊥＇，最后，还指出了根式１／２（ｎ２ｓｉｎ２θ－１）在什么情况下应取正值，在什么情况下应取负值．     

电磁辐射与环境

 进入21世纪以来,人类社会的科技水平得到了前所未有的发展。在信息交互频繁的时代,即时通讯已成为我们日常工作生活必不可少的帮手。手机、无线网络、视频信号等信息大都以电磁波为载体传输,给我们带来了极大的方便。但伴随着通讯的发展,电磁辐射给人类社会造成的影响也越来越大,我们生活的环境中到处都充斥着电磁波,每时每刻都会有无数的电磁信号穿过我们的身体,由于大量电磁波的存在,我们的通讯也受到了很多干扰,这些都或多或少地影响到了我们的生活。如何使电磁通讯朝着有利于社会发展的方向进行是我们现阶段面临的重要问题。     

协差阵奇异时的最优投资组合

给出了协差阵半正定且有n-r个零特征值的一般情况下,Markowitz均值——方差最优投资组合模型的解及由单纯形表求得n-r个无风险基金权重的最优解.     

具有性质cr+1=3,ar+1=3a+1或 4a的(a+1,3)型距离正则图

设г是直径为d且型为(a 1,3)的距离正则图,其中a≥2.用l(c,a,b)表示交叉阵列ι(г)中列(c,a,6)t的个数,记r=r(г)=l(c1,a1,b1),8=8(г)=l(Cr 1,ar 1,br 1)及t=t(г)=l(cr s 1,ar s 1,br s 1).那末,若Cr 1=3,ar 1=4a或3a 1,则d=r t 2.