过冷降膜在红外隐身中的应用研究

提出了利用过冷降膜技术对军事目标进行红外隐身的新构想。建立了层流过冷降膜的流动与传热模型,得出了层流降膜自由表面温度分布的解析表达式,分析了影响液膜自由表面温度的各种因素,计算了过冷降膜对军事目标的红外抑制效果。结果表明:过冷降膜是一种简单有效的红外抑制技术,增大液膜流动的Re数和降低液膜入口温度均可增强对特定目标的红外隐身效果,该技术在军事目标的红外隐身方面应用前景广阔。     

地面目标红外特性及其隐身技术研究

随着红外搜索与制导技术的飞速发展,对于地面目标红外特征及其隐身技术的研究具有越来越重要的军事意义.在简化目标传热模型的基础之上,计算出目标的瞬时温度变化,并与背景的温度比较发现,目标与背景在一天之中均存在明显温差,最大温差可达10℃.从目标与背景的辐射对比度出发,分析了辐射对比度与目标表面发射率以及目标与背景温差的关系,发现了当目标与背景温差控制在±4℃之内时,采用固定发射率涂料可以使目标达到红外隐身的目的.     

TEM characterization of chemically synthesized copper–gold nanoparticles

Dodecanethiol-capped Cu–Au nanoparticles, synthesized via a successive two-phase (water/toluene) and galvanic-exchange procedure, were characterized using transmission electron microscopy (TEM). The size range of the particles is around 1–7 nm. Electron-induced morphological evolution was observed under high resolution (HR) TEM. Cuboctahedral morphology was found to be thermodynamically stable. Electron-induced aggregation of two particles was also observed. Chemical ordering of cuboctahedral particles was studied by atomic-resolution high angle annular dark field (HAADF) imaging in scanning TEM (STEM) mode and energy dispersive X-ray (EDX) element mapping using a silicon drift detector (SDD). The particles were found to be Cu–Au mixed, and to be stable in air. Surface plasmon resonance (SPR), which is dependent on local structure and morphology, was investigated by electron energy loss spectroscopy (EELS).     

Anechoic chamber qualification: traverse method,inverse square law analysis method,and nature of test signal

Qualification of anechoic chambers is intended to demonstrate that the chamber supports the intended free-field environment within some permissible tolerance bounds. Key qualification issues include the method used to obtain traverse data, the analysis method for the data, and the use of pure tone or broadband noise as the chamber excitation signal. This paper evaluates the relative merits of continuous versus discrete traverses, of fixed versus optimal reference analysis of the traverse data, and of the use of pure tone versus broadband signals. The current practice of using widely space discrete sampling along a traverse is shown to inadequately sample the complexity of the sound field extant with pure tone traverses, but is suitable for broadband traverses. Continuous traverses, with spatial resolution on the order of 15% of the wavelength at the frequency of interest, are shown to be necessary to fully resolve the spatial complexity of pure tone qualifications. The use of an optimal reference method for computing the deviations from inverse square law is shown to significantly improve the apparent performance of the chamber for pure tone qualifications. Finally, the use of broadband noise as the test signal, as compared to pure tone traverses over the same span, is demonstrated to be a marginal indicator of chamber performance.     

Method of state code matrixes in the realization of optical switching using Perfect Shuffle

Based on the Left Perfect Shuffle (LPS) optical communication network constructed by cascade multi-stage LPS interconnection, using Looping algorithm, any arbitrary sequence of the input signals can be realized. However, instead of obtaining the simultaneous state codes of the same level node switches through mathematical analytical expressions directly, only routing tags of each channel can be obtained through mathematical analytical expressions so as to draw out topological chart of the network to obtain the state codes implied in the chart. Thus, the states of the switches cannot be directly programmed and controlled by computer in practical application. In this paper, based on the Looping algorithm, a method of stage code matrixes is presented to resolve this problem. By using the method, the simultaneous state codes of the same level’s four node switches can be directly obtained, which is convenient for the computer to provide controlled signals needed to finish the permutation for each node switch. The method of stage code matrixes provides further theoretical basis for the realization of optical switching by integration of Perfect Shuffle and high-speed optical switches.     

水面航行潜艇红外特征模拟研究

潜艇的红外辐射特征是红外探测系统发现潜艇并进行跟踪的依据,研究潜艇红外特征模拟方法对潜艇探潜和修正对敌潜艇制导数据具有一定参考价值。从潜艇的外部环境出发,分析了影响水面航行潜艇红外特征的多种复杂因素,建立了传热模型,给出传热边界方程,模拟了潜艇表面红外特征,估算了探潜距离。     

电场极性对池沸腾换热影响的实验研究

利用EHD技术对工质R123进行了非均匀高压电场下电场极性对池沸腾换热影响的实验研究.结果表明,无论加正、负电压,强化系数均随热流密度的增加而下降,最终达到稳定值;高热流密度下,正电压有较弱的强化效果,负电压对沸腾换热具有削弱作用;正电压下的强化换热效果优于负电压下的强化换热效果.     

一种ICF靶用智能靶涂层的结构和性能表征

 合成了一种材料N,N′-二苯并咪唑-苝二酰亚胺(PV),经多次真空升华提纯,产率为68%,纯度达95%以上。利用傅里叶变换红外光谱（FTIR）、紫外/可见吸收光谱（UV/Vis）、元素分析、热失重分析（TG）对该产物的结构和性能进行了表征。结果表明:苝四甲酸二酐（PTCDA）与邻苯二胺反应,易转化成二苯并咪唑苝类衍生物。该PV材料在450～750 nm范围内有两个强的吸收峰,其初始热分解温度约为510 ℃,热稳定性较好。     

铷原子气体自旋噪声谱的测量与改进

利用自主设计并制作的基于现场可编程门阵列的实时傅里叶变换采集卡(FFTsDAC),采用线偏振光检测碱金属铷原子气样品中的自旋随机涨落(即自旋噪声谱).详细讨论了背景噪声以及自旋噪声随探测光光强的变化关系,证实了自旋噪声来自于系统中自旋的随机涨落.对比了两种FFTsDAC(8 bit采样的FFTsDACl和12 bit采样的FFTsDAC2)的测量性能,分析了影响实验信噪比的因素.FFTsDAC2具有更高的测量效率和采样深度以及更长的单次采样时间,因而具有更高的信噪比和更好的频率分辨率,与数值模拟的结果一致.