HF and DF laser action by a pulsed microwave discharge

A pulsed electrodeless microwave discharge withE-field enhancement by a tapered waveguide has been employed to produce HF and DF laser radiation from premixtutes of SF6+ H6and SF6+ D2. The 720 patm (690 patm) HF (DF) laser had an average multiline output power of 6 mW (1 mW) for an efficiency of 0.1 percent (0.02 percent) while operating at 1 kHz (450 Hz) pulse-repetition frequency (PRF). The HF (DF) laser was operated at reduced output power and efficiency up to 4.2 kHz (2.5 kHz) PRF. Reduced HF laser efficiency was obtained when C3H8was substituted for H2.     

微波干涉仪测量气体放电管电子密度

本文用3厘米微波干涉仪,以锁相放大器作检测器,测量了微波通过气体放电管时所引起的相移.研究了在放电管中添加N_2、He、Xe等气体对电子密度的影响.     

Low-cost glow discharge tube microwave frequency sensor

Inexpensive commercial neon lamps are observed not only to sense the presence of low-power RF radiation levels, but also to determine the frequency of the incident radiation with relatively good accuracy.     

一种自热式阴极的横向放电特性

本文以石墨阴极为例介绍了一种自热式阴极的横向放电特性,指出热电子发射是该阴极的主要机理。     

对一种具分形特征的电磁吸波材料的初步分析

研究了一种基于Salisbury屏的微波吸收材料,提出了一种具有Minkowski分形特征、表面加载阻抗的双方环形电磁带隙结构的吸波材料。该种材料具有薄、轻、吸收频带范围宽的优点,且吸波深度深于同等条件下没有分形特征的吸波材料。     

Power transfer characteristics of a microwave reverberation chamber

Power transfer through a microwave reverberation chamber is studied theoretically and experimentally. Two configurations are employed as follows. In the first, the chamber contains a transmitting antenna and a receiving antenna; in the second, it contains a transmitting antenna and a receiving D-dot sensor. For each configuration a theoretical model is derived and laboratory measurements are carried out for the power gain of the chamber as a function of frequency. The models prove useful in predicting the observed variation of gain with frequency, and they provide insight into the importance of power flow to the chamber walls and to the receiving antenna/sensor     

一种用于小型激光器的新颖放电结构的放电性质研究

依据微空心阴极自持的辉光放电结构,设计了一款新颖的微小放电结构.用空气进行了有关的放电实验,稳定的直流辉光放电,放电气压最大能够达到66.7 kPa.放电的伏安特性具有正的斜坡,放电能够稳定地运行,而不需要个体镇流电阻.在气压为40 kPa和放电电流为60 mA时,放电等离子体中的电流密度估计为0.048 A/cm2,功率密度估计为52.8 W/cm3,电子密度估计为2.7×1013 cm-3.实验结果表明:这种高气压、大体积、高电子密度的放电等离子体能够用作小型激光器的工作介质.     

UWB passive microwave imagery from static discharge effects

It is well known that spark transmitters can be sources of ultra-wideband (UWB) radiation. It is also known that high-voltage low energy static discharges are ubiquitous in nature, whenever there is friction between surfaces. Provided is a simple electromagnetic model and it is suggested that it is feasible to construct an ultra-wideband correlator capable of imaging a region of space containing such sources. This would permit a new window of observation on several physical processes, with applications ranging from observations of ice flows to covert operations.     

Analysis of MODFET microwave characteristics

A new ac MODFET model including distributed effects is presented. We have solved the wave equation of the MODFET, which automatically accounts for the propagation delay, capacitances, and charging resistances. Using a frequency power series proposed by Ziel, we derive an approximate analytic expression for the four intrinsic Y parameters. We verify that the truncated frequency power expansion used is accurate for frequencies up to twice the unilateral power-gain cutoff-frequency. The Y parameters derived hold from the threshold region to the edge of saturation. The theory was used to reproduce the dc characteristics of a 1-μm GaAlAs/GaAs MODFET together with its microwave characteristics measured from 2 to 18.4 GHz. Device parameters so obtained by fitting the I-V characteristics were used to calculate the MODFET Y parameters. They yield a closer fit to the data than the Y parameters obtained from conventional equivalent-circuit models. A reasonable prediction of the scattering parameters measured from 2 to 18.4 GHz is achieved with those device parameters. Further improvements can be obtained by optimizing the parasitics.     

Linearisation of microwave point-contact-detector characteristics

The characteristics of microwave measuring-grade point-contact detectors can be linearised over a wide dynamic range with a simple circuit with only one adjustable parameter for nonlinearity. The need for matching of detectors is also largely eliminated.     

一款高效微波聚焦热疗系统的设计

为了有效提高微波热疗系统的能量利用效率,改善肿瘤治疗效果,设计一款高效率微波聚焦热疗系统。该系统的辐射器采用36单元环形阵列天线,人体等效模型采用三层匹配介质加载,并利用天线聚焦算法实现辐射器能量在人体模型深部的靶向聚焦。仿真和实验结果表明,相比于单层人体匹配介质层加载的系统,该系统能量利用效率达到之前的3倍,既实现了体外微波能量的有效穿透,又保证了穿透到人体内部的电磁能量靶向聚焦,克服了一般微波热疗系统中由于散射和折射引起的电磁能量损耗问题。     

Properties of nanosilicon obtained by plasma chemical decomposition of monosilane in a microwave discharge

Investigations of nanoscale silicon powders obtained by plasma chemical synthesis in various process parameters were carried out by transmission electron microscopy, X-ray photoelectron spectroscopy, and infrared (IR) spectroscopy. It was demonstrated that the powders consist of spherical particles with an average diameter from 20 to 30 nm. Each particle includes a single-crystal silicon core and amorphous shell whose chemical composition is defined by bonds of silicon with oxygen and hydrogen. The measurements of photoluminescence (FL) show the presence of dim near-infrared FL in the specimen powders, and more intensive emission around 420 nm in the suspension of the powder in ethanol. The character of this emission has not been determined yet.     

新型针板电极放电特性的研究

研制成功一种二千瓦横流电激励连续ＣＯ２激光器，采用了新型针板式电极结构，其阳极为平面形铜板电极，阴极为二排针形钨杆电极，每排１００支均匀分布，电极之间的距离为３５ｍｍ，本文论述这种新型针板式电极的放电特性。     

自适应可变磁阻传感器放大器及其应用

LM1815是省略门电路的自适应传感放大器,适用于马 达控制。LM1815提供一次性脉冲输出,其前沿与反向过零 基准输入信号恰好一致。正常工作时,计时基准信号在外部 被处理（延迟）并且返回LM1815,然后逻辑输入可以用作 传送到输出驱动极的定时基准或处理信号。     

Photoinduced discharge characteristics of xerographic photoreceptors

The light-induced discharge characteristics of xero-graphic photoreceptors are studied both theoretically and experimentally, using amorphous films of Se and PVK poly(N-vinyl carbazole). In addition to the dependence of the discharge rate on quantum efficiency, trapping, and transit-time effects, several new variables are considered theoretically, including the electric-field dependence and the sublinear light-intensity dependence of the carrier generation mechanism. This new theory provides the capability of computing the discharge characteristics of model xero-graphic photoreceptors. Parameters such as quantum efficiency, mobility, thickness, and dielectric constant can be varied in the calculation and their effect on the discharge characteristic can be studied. Applications of the results to the study of practical xero-graphic photoreceptors are also presented.     

Capacitance-voltage characteristics of microwave Schottky diodes

Based on an analytical solution of Poisson's equation, the authors calculate/capacitances of metal circular dots and metal stripes on the surface of a doped semiconductor material. When the dimensions of the dot or stripe are much larger than the depletion region, the results are reduced to the conventional formula for a parallel-plate capacitor. In the opposite limit, the overall capacitance is determined by the edge effect. This edge capacitance is proportional to the device periphery, with the coefficient of proportionality dependent on the shape of the metal. The parallel-plate component of the device capacitance is modulated by the applied voltage; the edge component is nearly independent of the applied voltage. Hence, the largest capacitance modulation is achieved in devices with the smallest ratio of the device periphery over the device area, which has the smallest edge effect. The measured capacitances of small round GaAs Schottky barrier diodes are in reasonable agreement with calculated results     

Phase characteristics of microwave avalanche-diode amplifiers

The phase and gain characteristics of wideband, coaxial X band avalanche-diode amplifiers have been determined, and typical data are presented for an 11 GHz amplifier. At a gain of 15 dB, the phase linearity was less than 4°, the a.m.-p.m. conversion was less than 8 deg/dB and the phase sensitivity to current was about 0.2 deg/mA.     

10大气压X光预电离XeCl准分子激光的增益特性

采用振荡放大技术,研究了10个大气压的X光预电离放电XeCl准分子激光的增益特性。实验结果表明,在Xe/HCl=10:1情况下,充入不同的Ne稀释气体,对应于最大小讯号增益的工作气压P_(max)随着Ne气成份的增加而增加,而不同混合比下P_(max)时含有的HCl绝对分压几乎保持不变。