On radar accuracy using beam wave in random media

The accuracy of radar detection is measured in this paper through comparing the laser radar cross-section (LRCS) to RCS data for plane-wave incidence in free space. This is to study the performance of backscattering enhancement from conducting targets with finite size. LRCS is calculated using beam wave incidence propagating in a random medium. Targets are of large size with relatively complex cross-sections. E-wave polarization is assumed for incident waves in continuous random media with different spatial coherency.     

Radiophotolumenescence of Irradiated Polymethylmethacrylate Doped with Some Charge Transfer Complexes

Radiophotolumenescence (RPL) of irradiated and non irradiated thin films of polymethylmethacrylate (PMMA) doped with anthracene (Anth) as a donor, and tetracyanoquinodimethane (TCNQ) as an acceptor, has been investigated. The RPL – glow spectrum was recorded to study the characterizing emission bands from the point of view of glow peak position and intensity and hence the prospective relative sensitivities. RFL – signal fading after one month storage in dark at room temperature post gamma irradiation was also studied. PMMA doped with 6:4 donor to acceptor ratio has been proved to be the most sensitive one with less fading regarding gamma detection. On the other hand 2 Anth: 8 TCNQ was found to be the proper dopant concentration ratio for thermal neutron detection.     

Reaktion von Pyridin-2-Carbonsäure Mit Tetrabutylammonium-Tetrachloro-Nitridotechnetat(VI) Sowie Tetrabutylammonium-Tetrachlorooxotechnetat (V)

Abstract

The reaction of 2-pyridine carboxylic acid (Hpic) with (n-Bu₄N)[TcNCl₄] and (n-Bu₄N)[TcOCl₄] in ethanol and methanol, respectively, yields the dinuclear μ-oxo complex [(pic)₂NTc-O-TcN(pic)(Hpic)Cl] and the monomeric complex [TcO(pic)₂Cl].

Visible and infrared spectroscopy, ESR, ¹H-NMR and ⁹⁹Tc-NMR have been used to characterize the new compounds. The most important field of application for the new compounds synthesized is radiodiagnostics.     

A K-shell model for laser-produced Al plasma

The spectra from laser-produced plasma have been simulated by the newly developed model. The simulation agrees well with the experimental results, which can prove that the K-shell model is suitable for the application of the spectrum from laser-produced plasma. Also, the jkl satellite lines were found important for predicting the spectra.     

Retrieval of currents of multiply charged ions emitted from laser-produced carbon plasma

The emission of ions from laser-produced carbon plasmas is investigated by a deconvolution of ion collector signals. The deconvolution is based on the use of Kelly and Dreyfus function expressing the time-resolved ion current to recover hidden peaks in an ion collector signal. The parameters of recovered C ^q+ (1?≤?q?≤?6) currents make possible the quantification of properties of laser-produced plasmas. The drift and peak velocities of C ^q+ ions, the abundance of ions and the plasma temperature are presented in the dependence on focused laser beam energy. The carbon plasma was generated employing either single 9-ns pulses of second harmonics (532 nm) of Nd:YAG laser or pulses repeated at a stable repetition rate of 30 Hz.     

Investigations of the optical spectra and spin-Hamiltonian parameters for the rhombic Yb centers in garnets

Two complete diagonalization (of energy matrix) methods (CDM-I and CDM-II) are used to calculate the six optical spectral band positions and nine spin-Hamiltonian (SH) parameters (g factors g_i and hyperfine structure constants ¹⁷¹A_i, ¹⁷³A_i, where i=x, y, z) for Yb³⁺ ions in the rhombic dodecahedral sites of garnets Y₃Al₅O₁₂, Lu₃Al₅O₁₂ and Y₃Ga₅O₁₂. In CDM-I, the Hamiltonian concerning energy matrix does not contain the Zeeman and hyperfine interaction terms, whereas in CDM-II, it does. So, in CDM-I, the SH parameters are obtained by first-order perturbation method or the equivalence between SH and Zeeman term (or hyperfine interaction term) and in CDM-II, the SH parameters and optical spectral band positions are calculated together. The results obtained from both methods are not only close to each other, but also in reasonable agreement with the observed values. So the second-order perturbation formulas of SH parameters developed recently are incorrect and unnecessary.     

典型的三聚氰胺致幼儿肾结石红外光谱分析

从云南省第一人民医院得到经过医学证实的典型三聚氰胺肾结石,将2 mg肾结石与200 mg KBr一同放入玛瑙研钵中研碎,进行压片。用Perkin-Elemer公司生产的spectrum 100光谱仪得到了该结石的红外光谱。吸收峰在4 000～2 000 cm-1之间有3 487,3 325, 3 162, 2 788 cm-1,在1 700～1 000 cm-1之间有1 694,1 555,1 383,1 340,1 189,1 122 cm-1,在1 000～400 cm-1之间有993,782,748,709,624,585,565,476 cm-1。结石的红外光谱经过与文献报道的饲喂含氰尿酸、三聚氰胺宠物饲料后猫的肾结石的红外光谱图及普通人肾结石的红外光谱图对比,相差很大,说明该患儿结石与宠物结石及普通人肾结石的成分相同的可能性不大;分别与三聚氰胺与尿酸的红外光谱图对比,各有50%的相似性; 将三聚氰胺、尿酸按1∶1混合后,红外光谱出现的峰在4 000～2 000 cm-1 之间有3 469,3 419,3 333,3 132,3 026,2 827 cm-1, 在1 700～1 000 cm-1之间有1 696, 1 656, 1 555, 1 489, 1 439, 1 350, 1 311, 1 198, 1 124, 1 028 cm-1, 在1 000～400 cm-1之间有993,878,814,784,745,708,619,577,475 cm-1,将其与结石的红外光谱对比,发现两张图谱有83.3%的相似性,由此得出典型三聚氰胺尿结石的主要成分为三聚氰胺和尿酸。     

应用导数荧光光谱和概率神经网络鉴别合成色素

实验测量了食品色素胭脂红、苋菜红、诱惑红和工业色素苏丹红Ⅳ溶液分别在波长为300,400,440和380 nm的光激发下产生的荧光光谱.对这4种红色素的各8个溶液样本选取60个发射波长值所对应的荧光强度作为网络特征参数,训练、建立概率神经网络.据此,对32个色素溶液样本进行种类识别.为解决原始荧光光谱重叠造成识别准确率不高的问题,应用导数荧光光谱,将二阶导数光谱数据作为网络特征参数,建立网络,进行识别,识别准确率达100%.由此,提出了应用二阶导数荧光光谱结合概率神经网络对合成色素方便、快捷、准确地进行种     

重金属铅离子胁迫下玉米叶片光谱弱差信息的DSAT甄别模型

光谱间微弱信息测度是当今高光谱遥感研究难点之一,传统光谱测度方法难以区分光谱信息的微弱差异。研究设计了不同浓度的铅(Pb)污染实验,并测量了不同浓度铅离子(Pb2+)胁迫下玉米叶片的高光谱反射率、叶绿素含量及Pb2+含量,但是从所测结果得出,不同浓度Pb2+胁迫下的光谱相似性相关系数均达到0.999,难以区分不同浓度Pb2+胁迫引发的光谱间微弱信息差异和污染程度。针对这一情况,基于光谱微分处理、正切函数增强、光谱角量度与波谱分段检测等,提出了一种新型的相似光谱测度方法,即微分光谱角正切(derivative spectral angle tangent,DSAT)法。为了验证DSAT在区分相关系数达0.99以上相似光谱的可行性和有效性,将DSAT用于不同浓度Pb2+胁迫玉米叶片的整体波形与光谱区间子波形的信息差异性度量与检测。实验结果得到,波形差异信息与玉米叶片中叶绿素相对浓度与Pb2+含量显著相关。进而也证明DSAT法在甄别较高相似性光谱间差异上具有更好的实用性和优越性。