防电磁辐射服装屏蔽效能测量方法的研究

在总结国内外防电磁辐射屏蔽服的屏蔽效能测量方法的基础上,提出了一种基于现有测量条件且简单可行的屏蔽服屏蔽效能的测量方法。并通过仿真分析确定了屏蔽服屏蔽效能的测量频率范围、使测量误差最小化的测量探头的选择以及具体测量步骤,旨在探讨防电磁辐射屏蔽服装屏蔽效能的测试方法,为制定相应标准提供参考。     

阈值法在毫米波目标辐射信号去噪中的应用研究

小波域阈值法去噪以其效果好,易编程实现而广泛应用到图像及信号的去噪中。该文在分析了毫米波目标辐射信号的小波系数特征后,提出使用非负小波系数代替信号的小波系数。对于确定的阈值,推导了重构信号均方差最小时,非负小波系数的去噪方法,实验表明该文算法具有较好的去噪效果。     

Proton irradiation of CdTe thin film photovoltaics deposited on cerium‐doped space glass

Space photovoltaics is dominated by multi‐junction (III‐V) technology. However, emerging applications will require solar arrays with high specific power (kW/kg), flexibility in stowage and deployment, and a significantly lower cost than the current III‐V technology offers. This research demonstrates direct deposition of thin film CdTe onto the radiation‐hard cover glass that is normally laminated to any solar cell deployed in space. Four CdTe samples, with 9 defined contact device areas of 0.25 cm², were irradiated with protons of 0.5‐MeV energy and varying fluences. At the lowest fluence, 1 × 10¹² cm⁻², the relative efficiency of the solar cells was 95%. Increasing the proton fluence to 1 × 10¹³ cm⁻² and then 1 × 10¹⁴ cm⁻² decreased the solar cell efficiency to 82% and 4%, respectively. At the fluence of 1 × 10¹³ cm⁻², carrier concentration was reduced by an order of magnitude. Solar Cell Capacitance Simulator (SCAPS) modelling obtained a good fit from a reduction in shallow acceptor concentration with no change in the deep trap defect concentration. The more highly irradiated devices resulted in a buried junction characteristic of the external quantum efficiency, indicating further deterioration of the acceptor doping. This is explained by compensation from interstitial H⁺ formed by the proton absorption. An anneal of the 1 × 10¹⁴ cm⁻² fluence devices gave an efficiency increase from 4% to 73% of the pre‐irradiated levels, indicating that the compensation was reversible. CdTe with its rapid recovery through annealing demonstrates a radiation hardness to protons that is far superior to conventional multi‐junction III‐V solar cells.     

复杂环境背景下典型飞行器表面红外反射特性研究

飞机蒙皮对于背景辐射的反射可以作为红外目标识别的辐射源,但背景辐射通常来源于太阳辐射和地面背景辐射等辐射的综合作用,其复杂性和多变性也可能使飞机的红外反射辐射严重干扰红外制导的准确性,因此,研究复杂环境背景下的飞机蒙皮红外反射特性对于红外目标识别和红外导弹制导等应用具有重要意义.本文基于Schlick双向反射分布函数(...     

Design of an Internal Antenna with Near‐Omnidirectional H‐Plane Radiation Pattern over Ultra‐wide Bandwidth

In this paper, an ultra‐wideband internal antenna for use in mobile applications is proposed. The proposed antenna has symmetrical bi‐arm structures printed on the top and bottom of the substrate, and it occupies a compact area of 10 mm × 10 mm × 1 mm. The designed antenna has an impedance bandwidth from 3 GHz to 12 GHz and near omnidirectional radiation patterns over the frequency band of interest. The group delay between two antennas fabricated using the proposed design is less than 0.8 ns, and the maximum gain variation is about 3.16 dB.     

直线振子和V形振子的时域辐射特性

本文用时间步进法求解线天线的时域积分方程,计算分析了直线振子和V形振子的时域辐射特性。分析了馈源位置、加载大小对振子输入电流及远区辐射场的影响。对V形振子的长度及张角等参数作了优化,找到了获得前向辐射场强最大瞬时冲击值的结构参数,结果可供此类天线的设计参考。     

多光子J-C模型的研究

本文推广二能级原子J-C模型到多光子过程。求得在存在偏调情况下,单模相干场对二能级原子激发时的光子数几率分布函数,由此研究了原子受激辐射性质。     

对地观测的微波散射成像方法

以微波为探测手段进行对地成像观测,能够全天候、全天时工作,在许多技术领域得到了重要应用,对微波成像的新思想、新体制、新技术的探索,也是一个非常活跃的研究领域。该文提出了一种新的微波成像方法,称为微波散射成像方法,该方法可采用收发分置工作方式,工作时只需要以单色波照射待成像地域。原理性成像模拟结果表明,使用这种方法可以获得被观测地域高几何分辨率和高辐射分辨率的微波图像。     

微波半导体功率器件及其应用(第二部分)

本文介绍了微波半导体技术主要特点、功率器件和单片集成电路的特性及其应用。     

激光辐射下的固体双基推进剂的燃烧特性

燃速与辐射通量之间的关系可以由两支相交直线构成的线性方程进行描述,其中折点(交点)是外界辐射能作用下固体双基推进剂燃烧的一个重要特征。包括折点附近在内的燃烧特性可以采用Fourier方程进行分析。考虑到辐射在燃烧表面上形成的碳化层对辐射传递的阻碍作用,本文分析了1040,1041,N-5和N型推进剂的燃烧特性。导致两段函数和折点形成的主要原因是在辐射能到达凝聚相表面之前部分辐射能已经发生了损失。