微波炉用磁控管碳化钍钨阴极断裂失效分析

本文采用扫描电镜、X射线残余应力分析仪、金相显微镜等工具分析了微波炉用磁控管碳化钍钨阴极的断裂失效机理,碳化后钍钨阴极较粗大的晶粒与内应力是其断裂的主要原因。     

应用粒子动态分析仪研究水力旋流器流场

利用粒子动态分析仪(PDA),对水力旋流器内固相颗粒流场做了全面的测定,得出水力旋流器内固相颗粒的流态、浓度及粒度分布,为进一步查清水力旋流器的工作机理提供了重要理论依据。     

亚稳态惰性原子与SOCl_2传能反应产物SO(A)的发射光谱和强度分析

本文在流动余辉装置上,利用亚稳态惰性气体原子[He(2~3S)、Ne(~3P_(0,2))、Ar(~3P_(0,2))]与SOCl_2的专能反应,在(230-430nm)波段观察到了产物的发射谱,光谱归属为自由基SO(A~3∏_(2,1,0)→X~3∑~-)的跃迁。对光谱强度分析表明:SO(A→X)的偶极跃迁矩Re随核间距明显地变化。通过拟合,找出了这一变化的关系。另外,本文还计算了SO(A~3∏_0→X~3∑~-)跃迁的Franck-Condon因子。     

Analysis and development of a signal injection technique usingtransmission lines embedded at phased array aperture

In a performance monitoring/fault isolation and correction (PM/FIC) system of a phased array antenna, a built-in transmission line embedded in the array aperture is used for signal injection to check the signal flow. The authors present an analysis of electromagnetic coupling between a twin-lead transmission line and a dipole element. An analysis of the coupling between a transmission line and a linear array of dipole elements over a ground plane has also been developed. The calculated data compared with the measured data favorably. A development of microstrip-line signal injectors embedded in an aperture of a 2D array of monopole excited parallel-plate waveguides has also been made. Measurements of the feed and aperture distributions have been made and the measured distributions follow the designed feed distribution closely     

Bandpass filtering effect in tapered asymmetrical twin-core optical fibres

The spectral coupling characteristics in asymmetrical twin-core optical fibres under fusion tapering are investigated experimentally. It is found that appropriate filtering can be achieved by fusion tapering. It is evident that, with suitable choice of tapering length and fibre parameters, it is possible to fabricate economic all-fibre bandpass filtering devices for various applications.<>     

A study of residual stress distribution through the thickness of p+ silicon films [thermal oxidation effects]

The effect of thermal oxidation on the residual stress distribution throughout the thickness of heavily-boron-doped (p⁺ ) silicon films is studied. The deflection of p⁺ silicon cantilever beams due to residual stress variation throughout the film thickness is studied for as-diffused and thermally oxidized films. Cantilevers of as-diffused p⁺ silicon films display a positive curvature (or a negative bending moment), signified by bending up of the beams. Thermal oxidation of the films prior to cantilever fabrication by anisotropic etching modifies the residual stresses in the p⁺ film, specially in the near-surface region (i.e. the top 0.3 to 0.5 μm for the oxidation times used here), and can result in beams with a negative curvature even when the oxide is removed from the p⁺ silicon cantilever surface subsequent to cantilever fabrication     

无接触法测量多晶硅材料的少子扩散长度

用微波光电导谱仪无接触、非破坏性地测量了多晶硅的微波光电导谱,推导了由光电导谱计算多晶硅样品的少子扩散长度和表面复合速度的计算方法,并由此算得了样品的少子扩散长度和表面复合速度。测试区域是一个直径为3mm的圆斑。这是一种简便而又准确的测试方法。这样的方法还适用于GaAs薄片材料少子扩散长度的测量和计算。     

Microring resonator channel dropping filters

Microring resonators side coupled to signal waveguides provide compact, narrow band, and large free spectral range optical channel dropping filters. Higher order filters with improved passband characteristics and larger out-of-band signal rejection are realized through the coupling of multiple rings. The analysis of these devices is approached by the novel method of coupling of modes in time. The response of filters comprised of an arbitrarily large dumber of resonators may be written down by inspection, as a continued fraction. This approach simplifies both the analysis and filter synthesis aspects of these devices     

A semi-empirical representation of antenna diversity gain atcellular and PCS base stations

Predictions of uplink space-diversity gain in the cellular and personal communications systems (PCS) bands (near 850 MHz and 1.9 GHz, respectively), suffer from incomplete modeling of multipath angular spread σ. Using previously published measurements to reduce the gap, we show that σ~[distance]^-1/2 and that diversity gains are about 2 dB higher for PCS than for cellular     

Fabrication of Alq3／PBD OMQW Structures and Its Photoluminescence Characteristics

Organic multiple quantum well(OMQW)structures consisting of alternating layers of tris(8-quinolinolato)aluminum(Ⅲ）（Alq3)an 2-(4-biphenylyl)-5-(4-ter-butylphenyl)-(1,3,3-oxadiazole)(PBD)have been fabricated by organic molecular beam deposition(OMBD).The individual layer thickness in the multilayer samples was varied from 6 nm tp 20nm.The multiple quantum well structures were determined by low angle X-ray diffraction,optical absorption and photoluminescence(PL).The PL spectra narrow and the emission energy has been observed to shift to higher energy compared with that in the monolayer structure,suggesting a quantum size effect.