机载雷达罩涂层的研究概况

介绍了机载雷达罩涂层系统的研究情况,分别讨论了底漆,耐雨蚀涂层和抗静电涂层的性能及发展。     

The measurements of autonomy and technology for task svstems design

Numerous experiments in job enlargement, direct worker participation and autonomous workgroups have been reported. However, little cumulative knowledge has been gained through a lack of conceptual and theoretical bases. Moreover, worker autonomy and technology, the major variables in those experiments either were measured by questioning workers and supervisors and are consequently modified by their perception, or were measured in a very broad fashion.

In the present work more objective and specific measures for technology and autonomy, which can link job design research and experiments with job design practice, were developed and validated. Automony and technology are of course multidimensional concepts. Relevant aspects for job design are derived from a model for task related decision making which shows that the degree of worker autonomy is contingent on task technology and worker characteristics.

Technology is measured by cycle time, task repetitiveness, task skill level, disturbance level of a task and the disruption potential of a task system, through observation. A distinction is made between autonomy in regulation, which keeps the process on target by counteracting disturbances and autonomy in control which specifies targets. Measures for both types of autonomy are developed. The measures of technology and autonomy were tested in a sample consisting of 411 work stations in industry and proved to be effective and efficient for job design purposes.     

Conceptual problems in instrument design for biological measurements

This paper examines methodological problems and some philosophical issues in the development of biomedical instruments. Electrical measuring instruments for monitoring tissue electrical parameters (reflex therapy) are discussed at the applications level.Translated from Izmeritel'naya Tekhnika, No. 8, pp. 60–62, August, 1993.     

Factory design and process optimisation with flexibility measurements in industrial production

Manufacturing companies operate in increasingly turbulent and discontinuous environments. Uncertain projections regarding future sales, large volume fluctuations, the steady advance of new technologies, and ever-shorter product life cycles, combined at the same time with increasing product variety, demand the constant adjustment of production structures to meet the current market requirements. Uncertainty in the production area requires a continuous transformation of production structures to meet the current requirements on the market. This poses a challenge for manufacturers in the various branches of industry and creates an ever-increasing need for flexibility to find an economic balance, in times of tight budgets, between the prevailing market uncertainties and the correct arrangement of the production systems. In the following document, the applied experience is presented, extracted from the flexibility assessment tool economical flexibility measurement (ecoFLEX). It will be shown along with the practical experience gained in its application at a car-engines plant.     

宽频天线罩结构设计及制备工艺进展

天线罩是保护罩内各种仪器在恶劣环境条件下能够正常工作的一种设施,现代战争对天线罩的宽频化提出了越来越高的要求.在简述宽频天线罩设计原理和方法的基础之上,着重对国内外宽频天线罩的结构设计及工艺实现研究现状进行了综述,指出了我国与国外的差距及宽频天线罩的发展方向.     

雷达天线罩技术及其电性能研究综述

综述了雷达天线罩技术的现状和发展趋势,介绍了雷达天线罩的材料(包括基体材料、增强材料和夹芯材料)、罩壁结构以及成型工艺,并且从雷达天线罩的透波特性和辐射特性两个方面详细介绍了雷达天线罩电性能研究分析方法,为雷达天线罩的设计与制造奠定了基础.     

Side-line tunable laser transmitter for differential absorption lidar measurements of CO2: design and application to atmospheric measurements

A 2 microm wavelength, 90 mJ, 5 Hz pulsed Ho laser is described with wavelength control to precisely tune and lock the wavelength at a desired offset up to 2.9 GHz from the center of a CO(2) absorption line. Once detuned from the line center the laser wavelength is actively locked to keep the wavelength within 1.9 MHz standard deviation about the setpoint. This wavelength control allows optimization of the optical depth for a differential absorption lidar (DIAL) measuring atmospheric CO(2) concentrations. The laser transmitter has been coupled with a coherent heterodyne receiver for measurements of CO(2) concentration using aerosol backscatter; wind and aerosols are also measured with the same lidar and provide useful additional information on atmospheric structure. Range-resolved CO(2) measurements were made with <2.4% standard deviation using 500 m range bins and 6.7 min? (1000 pulse pairs) integration time. Measurement of a horizontal column showed a precision of the CO(2) concentration to <0.7% standard deviation using a 30 min? (4500 pulse pairs) integration time, and comparison with a collocated in situ sensor showed the DIAL to measure the same trend of a diurnal variation and to detect shorter time scale CO(2) perturbations. For vertical column measurements the lidar was setup at the WLEF tall tower site in Wisconsin to provide meteorological profiles and to compare the DIAL measurements with the in situ sensors distributed on the tower up to 396 m height. Assuming the DIAL column measurement extending from 153 m altitude to 1353 m altitude should agree with the tower in situ sensor at 396 m altitude, there was a 7.9 ppm rms difference between the DIAL and the in situ sensor using a 30 min? rolling average on the DIAL measurement.     

Compact double focusing mass spectrometer design for partial pressure measurements

A double focusing mass spectrometer with Wien filter and magnetic deflector (both located in the same pole-gap) is proposed as a partial pressure analyzer. The magnetic field area to accommodate a beam of given radial angular aperture and the partial pressure sensitivity are compared with those of the single focusing instruments. The numerical examples given show a mass resolution increase of more than two compared with a single focusing instrument.     

Tu—154复合材料雷达罩大面积损伤修补

本文详细介绍了Ｔｕ－１５４复合材料雷达罩大面积损伤修补过程，通过选择适当的修补工艺，调整工艺参数，可使修补后的雷达罩攻气动以及电性能的要求。     

Graded Dielectric Inhomogeneous Planar Layer Radome for Aerospace Applications

Controllable artificial dielectrics are used in the design of radomes to enhance their electromagnetic (EM) performance. The fabrication of such radome wall structures with controllable dielectric parameters seems to be an arduous task. Further even minor fluctuations of dielectric properties of radome wall due to fabrication uncertainties tend to result in drastic degradation of radome performance parameters. In the present work, a novel inhomogeneous radome with graded variation of dielectric parameters is proposed which limits the constraints on fabrication and facilitates excellent EM performance characteristics. This radome wall consists of five dielectric layers cascaded such that the middle layer has maximum dielectric constant and electric loss tangent. The dielectric parameters of the layers on both sides of the middle layer decrease in a graded (or step-wise) manner. The EM performance characteristics of the IPL radome with graded dielectric parameters are superior to that of conventional monolithic half-wave radome.     

A Novel Metamaterial FSS-based Structure for Wideband Radome Applications

A novel metamaterial based FSS (frequency selective surfaces) structure is presented in this paper for wideband airborne radome applications. The proposed metamaterial-FSS structure consists of three layers, where a DPS (double positive sign) layer is sandwiched between a MNG (μ-negative) and ENG (ε- negative) layer, exhibits very good bandpass characteristics inside the operational band along with excellent roll-off characteristics outside the band. The EM performance analysis of the proposed structure has been carried out using transmission line transfer matrix (TLTM) method, which shows excellent bandpass characteristics over a wide frequency range. The transmission efficiency is over 95% both at normal incidence and at high incidence angles of 30°, and 60°. The frequency range extends from S- to X-band (2.5-9.9 GHz). In view of streamlined airborne radome applications, the reflection properties and insertion phase delay (IPD) are also determined at high incident angles.     

电动汽车动态工况的EMI测试技术需求与方案设计

针对电动汽车高度集成的电力驱动系统可能带来电磁兼容性问题,讨论国际上现行电动汽车电磁干扰(electromagnetic interference,EMI)测试标准中汽车工作状况设置,指出动态车辆工况设置及测试方法研究的必要性。并设计动态车辆工况信息直接、间接测量方案,实时获取车速ν_V、负载扭矩T_V、制动力F_S参数信息;其次,提出在动态车辆工况下特征频率提取采用实时频谱分析仪,最大发射值测量采用接收机的EMI测试方法;最后,提出读写时间戳法,实现动态车辆工况信息、EMI测试数据匹配。该集成方案可实现电动汽车动态工况下的EMI测试,且测试数据时间戳无累计误差。     

The design and operation of a new extractor gauge for UHV pressure measurements

The design of a new extractor gauge is described for ultra high vacuum pressure measurements. which employs a separate extractor electrode external to the grid. The advantages to be gained by the use of this system, the importance of providing an adequate ion extraction field and also of preventing the flow of electrons into the collector region, are discussed. A method is described of reducing the effect on the residual current of X-rays reflected onto the collector. This allows a residual current of 10^?14 A, at 1 mA electron current, to be achieved. For a gauge sensitivity of 10 torr^?1 this is equivalent to a residual pressure of 1 × 10^?12 torr. The addition of a modulator has been found to give a high modulation factor of 0.95 which should enable the low pressure limit to be extended to below 10^?14 torr.     

新型高温陶瓷天线罩材料的研究进展

导弹天线罩是保护导弹导引头天线在恶劣的环境下能正常工作的一种装置,其性能直接影响导弹的制导精度.天线罩材料经历了如下发展路径:氧化铝陶瓷→微晶玻璃→石英陶瓷→陶瓷基复合材料,并逐步向宽频带、多模通讯与精确制导方向发展.近年来,陶瓷基高速导弹天线罩技术发展十分迅速,重点介绍了高温陶瓷导弹天线罩的主要材料体系,并对各种体系陶瓷天线罩材料的特点及国内外研究现状进行了评述.     

Broadbanding of A-sandwich Radome Using Jerusalem Cross Frequency Selective Surface

Enhancement of electromagnetic performance of A-sandwich radome using aperture-type Jerusalem cross frequency selective surface (FSS) is presented. The Jerusalem cross FSS array is embedded in the mid-plane of the core of Asandwich radome to enhance the EM performance parameters over the entire Xband. For modeling the Jerusalem cross FSS embedded radome panel and evaluation of its EM performance parameters, equivalent transmission line method in conjunction with equivalent circuit model is used. A comparative study of Jerusalem cross FSS embedded A-sandwich radome and A-sandwich radome of identical material and thickness (core and skin layers) indicate that the new wall configuration has superior EM performance as compared to the A-sandwich wall alone configuration. The excellent EM performance of Jerusalem cross FSS embedded A-sandwich radome makes it a desirable choice for the design of normal incidence radomes (hemispherical/ cylindrical), near-normal incidence radomes (paraboloidal) and highly streamlined airborne nosecone radomes.     

高性能舰载雷达罩透波材料的优化设计

通过常规基体、增强材料和芯材等主要原材料之间的优化复合设计,开展单板、三夹层结构和五夹层结构各形式复合材料之间的制作、电性测试与分析,优化设计出了一种新型兼顾电性、力学性能的功能型五夹层结构复合材料,满足了高性能舰载雷达宽频带、高透波等电性指标要求,同时还满足了其高比强、刚度的力学指标要求,解决了传统型设计和材料通常无法满足其电性能、强刚度、低成本制作的矛盾。     

Experimental design of measurements for the solution of coefficient-type inverse heat-conduction problems

A numerical method is proposed for optimization of the spatial placement of a fixed number of temperature sensors in the solution of coefficient-type inverse heat-conduction problems.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 48, No. 3, pp. 490–495, March, 1985.     

Optical design in beam steering environments with emphasis on laser transmission measurements

Optical sensors applied to practical devices often encounter beam steering: the wander and/or diffusion of laser light. Here we provide a framework for minimizing the sensitivity of transmission-based sensors to beam steering without quantitative prediction of the severity of the beam-steering field. Typical goals are increased transmission and/or minimized fluctuations in transmission; such features can improve optical sensor performance (e.g., improved signal-to-noise ratio, response time, or spectral resolution). In our framework, we introduce a parameter for characterizing beam-steering severity. We then compare two approaches for absorption spectroscopy and show that the preferred approach depends on the total spectral range monitored, the spectral resolution desired, and the severity of the beam steering.