Frequency shift in cavities with rough walls

The influence of the roughness of the surface on the resonance frequency of an electromagnetic cavity is calculated. The roughness of the surface is described by a stochastic process and the frequency shift is then found as an expectation value. If the correlation distance of the surface roughness is much smaller than the curvature radius of the cavity wall, a quite simple formula for the frequency shift is found.     

White-emitting high-contrast low-voltage ac-electroluminescent multi-element display panels

To compete with LED displays, inexpensive ac-EL layer structures have been developed with high visual contrast in bright ambient. They can be driven with 50 V, 10 kHz by a simple oscillator, and they consist of monograin ZnS powder layers embedded in high-dielectric resin on black back electrodes, puncture-protected by an inorganic insulator film. All spectral colours are available. White emission can be obtained by mixing blue-emitting and yellow-emitting EL powder. Blue-violet-emitting powder can be embedded in resin that is dyed with fluorescent molecules to obtain all colour tints imaginable. Patterns can be obtained by dusting tacky resin dots, like in colour TV tube manufacture. Preparation is described and materials listed.     

基于BB84协议的量子密钥分发安全门限研究

本文分析了实际量子密钥分发过程中,量子态可能受到的各种影响因素;建立了相应的信道模型;推得了非理想信道BB84协议判别窃听的安全门限公式.通过计算与仿真,证明该公式用于估计BB84协议的安全通信门限更加准确,判断量子密钥分发过程中是否存在窃听更为有效,同时具有提高通信安全性和密钥分发效率的优点. 关键词： 信道模型 BB84协议 窃听判别 安全门限     

Reversals of signal-posterior monotonicity for any bounded prior

Paul Milgrom [Milgrom, P.R., 1981. Goods news and bad news: representation theorems and applications. The Bell Journal of Economics 12, 380-391] showed that if the strict monotone likelihood ratio property (MLRP) does not hold for a conditional distribution then there exists some non-degenerate prior and pair of signals where the higher-signal posterior does not stochastically dominate the lower-signal posterior. We show that for any non-degenerate prior with bounded support there exists a conditional distribution (satisfying several natural properties) and pair of signals such that the lower signal’s posterior stochastically dominates that of the higher signal. Thus, for every bounded prior, higher signals may represent strictly “worse” news.     

A sufficient condition for pancyclability of graphs

Let G be a graph of order n and S be a vertex set of q vertices. We call G,S-pancyclable, if for every integer i with 3≤i≤q there exists a cycle C in G such that |V(C)∩S|=i. For any two nonadjacent vertices u,v of S, we say that u,v are of distance two in S, denoted by d_S(u,v)=2, if there is a path P in G connecting u and v such that |V(P)∩S|≤3. In this paper, we will prove that if G is 2-connected and for all pairs of vertices u,v of S with d_S(u,v)=2, , then there is a cycle in G containing all the vertices of S. Furthermore, if for all pairs of vertices u,v of S with d_S(u,v)=2, , then G is S-pancyclable unless the subgraph induced by S is in a class of special graphs. This generalizes a result of Fan [G. Fan, New sufficient conditions for cycles in graphs, J. Combin. Theory B 37 (1984) 221-227] for the case when S=V(G).     

On the stability of the linear mapping in Banach modules

We prove the generalized Hyers-Ulam-Rassias stability of the linear mapping in Banach modules over a unital Banach algebra.     

Distributed variable-capacitance microstrip lines for microwave applications

Variable-capacitance microstrip lines are easily prepared on semiconducting substrate by use of IC-technology yielding a form of distributed nonlinear transmission line for high-frequency operation. Its cross section may be adequate to that of any varactor diode. Wave propagation determined by a very slow TM-surface mode is described by a general equivalent circuit thus characterizing the nonlinear properties of such lines. Optimum performance together with attainable configurations and possible applications are discussed.     

Resonance,phase front,and polarization-independence constraints of inhomogeneous fabry-perot interferometers

The major objective of this paper is to demonstrate the feasibility of imposing local resonance conditions while simultaneously controlling phase front properties upon transmission through slowly-varying Fabry-Perot type interferometers. The interaction of arbitrarily distorted incident phase fronts with double and triple-screened resonators is formulated, and appropriate design procedures are outlined. Special attention is paid to the significant effects of dielectric loading on the effective frequency band and to the cross polarization problem which arises, unavoidably, in conjunction with two-dimensional phase front distortions. The suggested design procedures are demonstrated via concrete numerical examples which are subsequently analyzed throughout a finite (20%) bandwidth.     

A monostatic inverse scattering model based on polarization utilisation

The solution of the inverse problem of electromagnetic scattering by smooth, convex shaped, perfectly conducting, 3-dimensional scatterers is analysed. Certain geometrical as well as physical-optics approximations were used to incorporate the concepts of the “Minkowski problem” of differential geometry into the space-time integral solution of electromagnetic scattering to yield the formal solution for the recovery of the surface profile of the scatterer from the scattered field data. Although various efficient solutions for target identification are available, still information contained in polarization-depolarization characteristics of the scatterer is not yet exploited to its full extent. Therefore the underlying assumption in this investigation was based on the fact that the “depolarization characteristics” of the scattered field do necessarily contain information regarding the surface profile of the scatterer.     

The characterization and property of polystyrene compounding of α-Fe<Subscript>2</Subscript>O<Subscript>3 </Subscript>in the nano-scale

84uq302v838p/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Fe₂O₃/polystyrene composite nanoparticles were synthesized in an oil/water microemulsion. Their structure was characterized by transmission electron microscopy, X-ray diffraction and Fourier transform-infrared spectrometry. An Ubbelonde viscometer, a Gouy balance and a model 283 potentiostat/galvanostat measured the molecular weight of the composite nanoparticles and their magnetic and electrical characteristics respectively.