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Adequate standards are essential to the practice of engineering. In no other fieid is this requirement more pressing than in the radio-frequency portion of the spectrum. This paper describes the organizations involved and the processes followed in the generation adoption, and dissemination of Standards Documents concerned with RF measurements. A listing of organization engaged in this activity, current Standards Documents, and work in process included. 相似文献
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A series of reports from Lund, Sweden, based on observed leakages of endogenous serum albumin in blood, suggested that repeated exposure to microwave radiation from GSM cellular telephones could alter the permeability of the blood-brain barrier at SARs that were well below the maximum permissible level for cellular telephones. While an effort to confirm had failed at SARs of 0.3-1.5 W/kg, it had confirmed extravasation of serum albumin at 7.5 W/kg: a level about four times greater than the maximum permissible level for cellular telephones. Currently, there is considerable interest from several laboratories around the world in replicating the reported occurrence of abnormal neurons in the rat brain resulting from leakage of endogenous serum albumin. 相似文献
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Radio-frequency oscillations are observed in alkali vapor-filled thermionic diodes at low vapor pressure. A review of the experimental phenomena and attempts at quantitative theoretical understanding is given. Possible applications are for energy conversion and as a diagnostic tool. 相似文献
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本文叙述了激光制导导弹四种制导方式的原理、应用、现状及发展趋势. 相似文献
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基于欧拉-自由梁模型理论得出弹性体导弹横向振动模型,用模态分析方法对模型进行求解。结合弹性导弹的刚体运动方程,得到包括横向振动和刚体运动的增广模型,对该模型进行鲁棒控制器设计,仿真结果表明,所设计的鲁棒控制器能够在保证弹体运动姿态控制的同时抑制横向振动。 相似文献
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为电视遥控制导导弹的作战效能评估建立了一种可行方案,提出了用目标杀伤概率和达到指定杀伤概率所需导弹数作为评价电视遥控制导导弹靶场效能指标。引入了等效易损体的概念模拟目标毁伤模型,并用目标毁伤模型来计算电视遥控制导导弹的作战效能,最后对影响电视遥控制导导弹作战效能的若干因素进行了分析。 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1982,70(12):1462-1464
The body currents induced in a human in conductive contact with various ungrounded metallic objects like cars, trucks, fences, etc., are calculated for the frequency band 10 kHz to 10 MHz. The calculated incident E-fields required to produce thershold perception and let-go currents indicate that the recently proposed ANSI guideline of 100 mW/cm2(∼615 V/m) in the frequency band 0.3 to 3.0 MHz may result in a potential for RF burns. 相似文献
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Basic principles and definitions of dielectric properties of materials are presented. Data from the literature on the dielectric properties of insects are briefly reviewed and discussed in relation to insect control by selective dielectric heating. Because early measurements of the dielectric properties of insects were taken on bulk samples of insects (insect and air-space dielectric mixtures), a means for converting the dielectric properties, or permittivities, of bulk samples of particulate materials to those of the solid particles is described. The technique uses the Landau & Lifshitz, Looyenga dielectric mixture equation and information on the bulk densities of air-insect mixtures used for dielectric properties measurements along with the densities of the insects. Such converted data for the dielectric constants and loss factors of the insects are presented and collected for comparison with other measurements of insect tissues and permittivity determinations from more recent microwave measurements of these same parameters. Resulting data are presented for reference, and comparisons are presented and discussed briefly. 相似文献
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介绍了多通道射频连接器国际标准提案的立项背景以及产品性能参数和特点,该提案包括两种型号产品,即L32-4型4通道射频连接器和L32-5型5通道射频连接器,可以重点应用于移动通信基站的共天馈场景,且已经在我国4G网络中作为重要方案被广泛采用. 相似文献
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文中对国外专利上出现的高速导弹的头罩设计及防护技术进行了综述。通过查阅大量国外有关高速导弹头罩防护技术专利,对头罩防护及设计方法进行了分类和梳理,分析了各种技术的优缺点及适用范围。随着导弹飞行速度的提高,头罩表面温度及热应力也不断升高。在航空界一般把马赫数 2.5作为热障的界线,低于这一值,气动加热不严重,可用常规的方法和材料设计、制造飞行器;高于该值,则必须采取克服气动加热问题的措施,如采用抛罩技术、加装激波锥、改变头罩的气动外形、对窗口加装冷却系统等措施。 相似文献
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一种对雷达探测巡航导弹能力的评估方法 总被引:1,自引:0,他引:1
根据巡航导弹航线规划特点和作战环境实际,估算了强面分布无源杂波的RCS;计算某巡航导弹各方位角的RCS值,从而得出探测强杂波中巡航导弹所需的改善因子。通过比较雷达性能指标,优选适合探测巡航导弹的雷达,为装备部署雷达网和改进雷达参数提供评估依据。 相似文献