A Primate-Restraint Device for Use in Microwave Biological Research

A restraint chair has been developed for use with subhuman primates in microwave biological research. The chair is essentially non-reflective, causing minimal perturbation of the field incident on the animal. The basic design of the device is simple and adaptable to different experimental configurations as required. Department.     

一种多体制兼容的微波成像新技术

虚拟透镜成像技术是一种可以兼顾远、中、近不同距离的成像新技术,但该技术是在被动成像的基础上发展起来的,适用于被动成像、半主动成像以及常规相控阵成像。在主动全息成像以及合成孔径成像系统中,由于天线单元依次工作并收发信号,目标回波信号具有不同的传播路径和相位延迟特性,因而不能直接采用虚拟透镜成像技术。文中对虚拟透镜成像技术进行扩展,针对主动全息成像和合成孔径成像的特点,引入了阵列属性参数,将其与信号传播路径和相位延迟特性进行关联,建立了一种多体制兼容的成像快速算法统一架构,并对相位加权算法进行了优化。所提出的新算法适用范围更广泛,且相位加权算法简洁易实现。最后进行了成像验证,实验及仿真结果证实了新算法的有效性。     

Coupling Errors in Cavity-Resonance Measurements on MIC Dielectrics (Short Papers)

Measurements on MIC dielectrics have been made by applying the theory of resonant cavities to either wholly or partly metallized substrates. Two different schemes of coupling are employed, depending upon the metallization. Errors occur in the derived value of /spl epsi/, due to the coupling, and are of opposite sense for the two methods discussed. They may be averaged to improve the overall measurement precision (0.5 percent).     

A Microwave Radio System for Pipeline Use

In the Texas-Illinois pipeline installation of a microwave relay, the reliability problem was emphasized by the distribution of some 2000 vacuum tubes and associated other components over more than a thousand miles of pipeline right-of-way. The general solution to the reliability problem was threefold, including the design of inherently reliable equipment, provision of full automatic switchover to standby in case of component failure, and special test facilities for rapid isolation of any degraded component.     

微波高功率双介质栅静电感应晶体管

提出了用同步外延法设计和制造具有双介质层栅结构和非饱和电流电压特性的高频高功率静电感应晶体管的关键技术.讨论了寄生栅源电容Cgs对静电感应晶体管高频功率特性的影响.描述了工艺上减小寄生电容、改善静电感应晶体管高频功率性能的主要方法和措施.成功地制造出频率在400MHz时输出功率大于20W、功率增益大于7dB、漏效率大于70%和700MHz时输出功率大于7W、功率增益大于5dB,漏效率大于50%的高性能静电感应晶体管.     

微波高功率双介质栅静电感应晶体管

提出了用同步外延法设计和制造具有双介质层栅结构和非饱和电流电压特性的高频高功率静电感应晶体管的关键技术.讨论了寄生栅源电容Cgs对静电感应晶体管高频功率特性的影响.描述了工艺上减小寄生电容、改善静电感应晶体管高频功率性能的主要方法和措施.成功地制造出频率在4 0 0 MHz时输出功率大于2 0 W、功率增益大于7d B、漏效率大于70 %和70 0 MHz时输出功率大于7W、功率增益大于5 d B,漏效率大于5 0 %的高性能静电感应晶体管     

A Percutaneous Wire Electrode for Chronic Research Use

A percutaneous wire electrode has been developed which permits long-term recording of intramuscular EMG signals. The electrode consists of a small coil wound from 0.0011 inch diameter wire and filled with silicone rubber. Easily inserted by means of a hypodermic needle, it has demonstrated reliable EMG recording for periods of up to thirteen months.     

A Microwave Decoupled Electrode for the Electroencephalogram (Short Papers)

The recording of the electroencephalogram (EEG) in an amplitude-modulated microwave field presents two related but distinct problems when conventional electrodes are employed. The electrode and its associated conductors extract power from the incident radiation, resulting in increased local power deposition which confounds dosimetric arguments and imposes local thermalization; the electrode tissue interface is a nonlinear system that demodulates amplitude-modulated signals with the results that the demodulate is additively mixed with the EEG. The problems were studied in a series of bench tests with conventional and thin-film microwave integrated circuit (MIC) electrodes. The latter are decoupled from the magnetic component of the field by virtue of radically reduced dimensions of the thin-loop component of its geometry, and suppression of dipole (i.e., electric field interaction) currents by use of integrated Nichrome series resistance. The result is that the demodulation artifact is undetectable in the ensemble averaged-power spectrum from the in vitro electrode up to an S-band incident-power density of 100 mW/cm/sup 2/. Thermalization was studied in a dielectric brain phantom with high-resistance monofilament leads to the MIC with a result that 0.6/spl deg/C heating is attributable to the electrode with prolonged exposure to a 50-mW/cm/sup 2/ field.     

A Switch Box for Use in Multicontact Depth Electrode Studies

The more frequent use of standardized multiple contact depth probes has increased the sites for EEG recording.     

A High-Accuracy Microwave Phase Standard for Use in Primary Calibration Laboratories

This paper describes the theory and construction of a broad-band, differential phase shifter for use over the frequency range of from 4.25 to 6.20 GHz. Perturbations of the phase shifter which cause it to deviate from the ideal 2/spl theta/ operation are discussed. The analysis follows that of Fox, but is carried out in the exponential form, and includes both phase and attenuation constants. A set of nonideal conditions are postulated: improper positioning and matching of the constituent components, improper electrical Iengths of the differential phase shift sections, and loss in the dielectric slabs. Expressions are derived for each of the above conditions that demonstrate the effect on the 2/spl theta/ operation of the phase shifter. Evaluation of the experimental model shows that it operates within the predicted limits of error, /spl plusmn/ 0.5/spl deg/.     

A Versatile Temperature Controlled Exposure Chamber for Microwave Bioeffects Research

A versatile temperature controlled microwave exposure chamber has been designed especially for use in microwave bio-effects research. The device uses a thermoelectric heat pump to cool the air in the chamber below ambient and a resistive heater for above ambient operation. A unique feature of the exposure chamber is that the radiating antenna can be either inside or outside of the chamber.     

高温结构陶瓷的微波快速烧结研究

研究了多模腔微波烧结系统对低损耗陶瓷材料快速烧结及其显微结构与性能。     

A Double Side-Band Amplitude-Modulated Multiplex System for Use over Microwave Radio

Microwave communications is one of today's most rapidly expanding fields in the radio art. Its inherent characteristics fit well into the communication needs of expanding industry. One of its important advantages over conventional communication means is the capability of handling numerous voice frequency channels over a single radio frequency carrier. This capability is made possible by the wide bandwidth which is available and can be transmitted at ultra high frequencies.     

Thin-Film Temperature Sensors for Biological Measurements

Dynamic as well as static temperature measurements are now possible in biological tissue using thin-film Cu-Ni microthermocouples. These probes which use a quartz substrate exhibit response times of less than a millisecond with thermal properties similar to tissue. Their thermoelectric EMF of 21 , ?m V/°C is linearly dependent on temperature over the range normally encountered in biological measurements. Probe-tip diameters as small as 10 ?m are being fabricated.     

一种多点测量并兼容多种传感器的黑体测温方法研究

机载红外扫描仪黑体温度测量是遥感数据定量化反演的依据,已经成为仪器设计的重要环节.由于黑体的面积较大,相对于目前一般使用的单点测温方法介绍一种多点测温方法,在黑体内放置多个温度传感器,通过扫描网络实现多点巡回测温,提高黑体测温准确度.同时,兼容多种不同精度的温度传感器,能够适应不同灵敏度的红外扫描仪对黑体测温精度的要求.     

Microwave Radio Relay Link for Military Use

Radio set AN/TRC-29 is the nomenclature for a frequency-modulated microwave radio link equipment designed for military use. It transmits in the band from 1700 to 2400 megacycles and will accept input signals between 30 cycles and 4.5 megacycles. In most cases, It will probably be used in conjunction with Multiplexer Set AN/TCC-13. This latter unit, which will also be described, is a pulse-position-multiplex equipment providing 23 voice channels. Facilities are included so that two multiplexer sets can be combined to provide 46 voice channels for transmission over one radio set. In place of 46 voice channels, the radio set can be used for transmission of radar signals. It can also carry television signals, but direct-current reinsertion amplifiers would be necessary in approximately every third station. Various other types of signals whose bandwidth lies within the 30-cycle-to-4.5-megacycle range can also be carried.     

微波化学反应器内等离子体空间温度的测量研究

针对矩形波导微波化学反应器,在低气压,低功率,纯甲烷微波放电情况下,用朗缪尔探针测量了石英反应管内等离子体的分布,用热偶计测量了微波等离子体在空间的温度分布。在谐振腔中心位置,等离子体的空间温度可以达到829℃;而在等离子体边缘区域,空间温度仅为78℃。     

微波辐射扫描电镜生物样品制备技术的研究

本文以生物样品为材料，对生物样品微波辐射扫描电镜样品制各技术进行了研究。实验结果表明，微波辐射制样是一个非常有效的方法。它不仅可以大大缩短各种反应的时间，而且还可以提高制样的质量。采用微波辐射技术制备扫描电镜生物试样可以将常规方法中临界点干燥前试样处理所需的６～８小时缩短为１．５～３．５小时，而其结果可以和常规制样方法的结果相媲美，甚至超过常规方法。     

Temperature Effects in Microwave Ferrite Devices

With proper choice of shape, it is possible to minimize the frequency shift of ferromagnetic resonance in microwave ferrite components operating over a wide range of ambient temperatures. Calculations have been made for minimum resonance frequency shift change in saturation moment. Curves relating the resonance frequency shift as a function of saturation magnetization are plotted for several ferrite geometries. Design curves are presented for reducing dependence of resonance frequency on temperature.