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71.
I. Kh. Abdukadyrova 《Journal of Applied Spectroscopy》2008,75(3):374-378
The influence of radiation damage on a number of lattice vibration parameters in two SiO2 modifications was investigated using IR reflectance spectroscopy. The radiation kinetics of changes in spectral characteristics
of SiO2 fundamental vibrations in crystalline and glassy states were determined. The reflectivity coefficient and the frequency of
degenerate vibrations as functions of dose showed minima, the locations of which were governed by the type of sample. At high
neutron irradiation doses (1021 cm−2), certain characteristics of the bands had the same values for both modified materials. Features of the radiation kinetics
of sample dynamic parameters were determined. It was deduced that the specific character of the observed radiation-induced
changes in spectral and dynamic parameters of vibrations near degenerate modes was due to both the accumulation of radiation
damage and a change in the force field surrounding bridging bonds, which is related to a change in the SiO2 structure.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 354–358, May–June, 2008. 相似文献
72.
P. P. Pershukevich I. K. Shushkevich E. A. Makarova K. N. Solov’eva 《Journal of Applied Spectroscopy》2008,75(5):706-713
We have studied the spectral luminescence properties of a zinc complex of dibenzobarreleno-substituted tetraazaisobacteriochlorin
(a synthetic tetrapyrrole pigment which is the structural analog of the biologically important chromophore isobacteriochlorin)
and a palladium complex of dibenzobarreleno-substituted tetraazachlorin. We have shown that despite the substantial effect
of aza-substitution on the electronic structure and the electronic spectra of the tetrapyrrole molecules, the effect of hydrogenation
of adjacent pyrrole rings on the spectral luminescence properties is similar in compounds with nitrogen and carbon bridges.
As in the free base case, the fluorescence of the studied zinc complex is strongly quenched at 293 K but flares up at 77 K
(temperature and viscosity-dependent quenching). To study the substituted Zn-tetraazaisobacteriochlorin, we determined the
position of the 0-0 band of the low-intensity transition S0 → S2 and showed that the S2 → S1 energy difference increases with bridge aza substitution. For the Pd complex of dibenzobarreleno-substituted tetraazachlorin,
we could not detect phosphorescence in the near IR region (to 1150 nm); we detected weak fluorescence.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 700–707, September–October, 2008. 相似文献
73.
74.
A large stack of lead-emulsion sandwich detector assembly was flown over Hyderabad, India. High energy gamma rays at the float
altitude were unambiguously identified from the cascades they induced, and their energies reliably determined by improved
methods. From an analysis of 163 gamma rays of energy ≳ 30 GeV, it is found that the differential energy spectrum is represented
by the power lawJ
r
(E)= 129·4E
−2·62±0·12 photons m−2 sr−1sec−1 GeV−1 at an effective atmospheric depth of 14·3 g cm−2; this is the first reliable balloon measurement of atmospheric gamma rays in the energy range 40–1000 GeV. After correcting
for the gamma rays radiated by the primary cosmic ray electrons, the production spectrum of gamma rays, resulting from the
collisions of cosmic ray nuclei with air nuclei, at the top of the atmosphere isP
r
(E, 0)=8·2 × 10−4 E2.60±0.09 photons g−1sr−1sec−1 GeV−1. The atmospheric propagation of the electromagnetic component due to the cascade process is also derived from the gamma ray
production spectrum. 相似文献
75.
超分辨重建技术及其研究进展 总被引:2,自引:0,他引:2
超高分辨成像技术一直是航天、遥感、目标识别等领域的研究热点。随着光学成像到光电数字成像的转变,如何提高CCD的几何分辨率,已成为研制高分辨光电成像系统亟待解决的问题。本文从理论和工程实现的角度介绍了超分辨成像的技术原理,分析了实现超分辨重建技术的几种方法,主要描述了微扫描和亚像元两种重建技术的实现方式,指出了目前超分辨技术存在的缺陷。最后,针对超分辨技术中无混淆重建带宽较窄的问题,提出了一种新的技术方案。该方案将光学编码技术与目前的亚像元技术相结合,可将重建带宽拓展3倍。研究结论指出:融合了光学,光电子学和信号处理的成像系统的综合设计,将是未来成像领域的一个重要研究方向。 相似文献
76.
200keV Xe+离子辐照使单晶YSZ由无色透明变成紫色透明,结果表明,能量为200keV,注量为1×1017cm-22的Xe+离子辐照YSZ单晶产生的损伤高达350dpa,在损伤区产生高密度的缺陷,但仍然没有发生非晶化转变。吸收光谱测试结果表明,产生吸收带的注量阈值大约为1016cm-2。注量为1×1016cm-2和1×1017cm-2的样品,吸收带峰值分别位于522nm和497nm。光吸收带可能与Zr阳离子最近邻的氧空位捕获电子形成的F型色心和Y阳离子近邻的氧离子捕获空穴形成的V型色心有关。 相似文献
77.
近红外光谱小波分析在土壤参数预测中的应用 总被引:5,自引:0,他引:5
从田间采集了150个田间土壤样本,在分析了所有样本的土壤参数统计特征之后,对原始近红外光谱数据进行了聚类分析,分别得到了50个土壤全氮和50个土壤有机质的等价样本及其对应光谱。对样本光谱曲线进行8层Biorthogonal小波包分解,分解得到的最低低频[80]结点对应着土壤水分以及土壤质地的光谱变化趋势,最高高频[8 255]结点对应着土壤粒度、光谱仪精度等引起的高频震荡。对以上两个结点进行重构并从样本光谱曲线中剔除以上影响成分,得到了对应的土壤参数特征光谱。基于特征光谱建立了土壤参数偏最小二乘回归模型:全氮偏最小二乘预测模型的预测系数rc达到了0.960,验证系数rv达到了0.920;有机质偏最小二乘预测模型的预测系数rc达到0.922,验证系数rv达到0.883。模型精度明显提高,满足实际生产的需要。 相似文献
78.
We prove the following result concerning the degree spectrum of the atom relation on a computable Boolean algebra. Let be a computable Boolean algebra with infinitely many atoms and be the Turing degree of the atom relation of . If is a c.e. degree such that , then there is a computable copy of where the atom relation has degree . In particular, for every c.e. degree , any computable Boolean algebra with infinitely many atoms has a computable copy where the atom relation has degree .
79.
The second CH stretching overtone of cyanoacetylene, HC3N, near 9700 cm−1 has been recorded by Fourier Transform Spectroscopy (FTS) and by Intracavity Laser Absorption Spectroscopy (ICLAS) with a Vertical External Cavity Surface Emitting Laser (VECSEL). In total thirteen bands have been identified in the highly congested spectra and rotationally assigned. Their rovibrational spectroscopic parameters have been obtained from a fit of the line centers. 相似文献
80.