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921.
922.
介绍了红外成像仿真的基本理论,讨论了利用Vega传感器模块将输入的可见目标图像生成红外图像的技术。该技术使用Creator软件进行三维几何建模和纹理映射,使用TMM软件进行红外材质建模;然后,用Mat软件进行大气衰减的计算;最后,用SensorWorks软件进行传感器特性建模,通过光电转换生成红外图像。以阿帕奇AH6直升机为例进行了红外图像仿真,结果表明,利用Vega传感器模块进行传感器建模,建模效果较好,成本低,易于工程实现。 相似文献
923.
Pressure effect study on the I-V property of the GaAs-based resonant tunnelling structure by photoluminescence measurement 下载免费PDF全文
This paper discusses the I-V property of the GaAs-based resonant tunnelling structure (RTS) under external uniaxial pressure by photoluminescence studies. Compressive pressure parallel to the [110] direction, whose value is determined by Hooke's law, is imposed on the sample by a helix micrometer. With the increase of the applied external uniaxial compressive pressure, the blue shift and splitting of the luminescence peaks were observed, which have some influence on the I-V curve of RTS from the point of view of the energy gap, and the splitting became more apparent with applied pressure. Full width at half maximum broadening could also be observed. 相似文献
924.
Influence of annealing conditions on impurity species in arsenic-doped HgCdTe grown by molecular beam epitaxy 下载免费PDF全文
Based on our previous work,the influence of annealing conditions on impurity species in in-situ arsenic (As)-doped Hg 1 x Cd x Te (x ≈ 0.3) grown by molecular beam epitaxy has been systematically investigated by modulated photoluminescence spectra.The results show that (i) the doped-As acting as undesirable shallow/deep levels in as-grown can be optimized under proper annealing conditions and the physical mechanism of the disadvantage of high activation temperature,commonly assumed to be more favourable for As activation,has been discussed as compared with the reports in the As-implanted HgCdTe epilayers (x ≈ 0.39),(ii) the density of V Hg has an evident effect on the determination of bandgap (or composition) of epilayers and the excessive introduction of V Hg will lead to a short-wavelength shift of epilayers,and (iii) the V Hg prefers forming the V Hg-As Hg complex when the inactivated-As (As Hg or related) coexists in a certain density,which makes it difficult to annihilate V Hg in As-doped epilayers.As a result,the bandedge electronic structures of epilayers under different conditions have been drawn as a brief guideline for preparing extrinsic p-type epilayers or related devices. 相似文献
925.
Electron tunneling effects on radiative recombination in modulation n-doped ZnSe/BeTe type-II quantum wells 下载免费PDF全文
We have studied the cyclotron-resonance absorption and photoluminescence properties of the modulation n-doped ZnSe/BeTe/ZnSe type-II quantum wells.It is shown that only the doped sample shows electron cyclotron-resonance absorption.Also,the undoped sample shows two distinctive peaks in the spatially indirect photoluminescence spectra,and the doped one shows only one peak.The results reveal that the high concentration electrons accumulated in ZnSe quantum well layers from n-doped layers can tunnel through BeTe barrier from one well layer to the other.The electron concentration difference between these two well layers originating from the tunneling results in a new additional electric field,and can cancel out a built-in electric field as observed in the undoped structures. 相似文献
926.
The luminescence properties of lanthanum silicon oxynitride(La-Si-O-N) series doped by trivalent Ce ions have been investigated to seek for tunable wavelength-conversion phosphor for white light emitting diode applications.Four compound hosts of LaSiO2N,La4Si2O7N2,La5Si3O12 N,and La2Si6O3N8 were synthesized and examined in this work.Crystallographic examination for the equal amount of Ce 3+ substitution indicated that the covalency degree decreased in a sequence LaSiO2 N > La2Si6O3N8 > La4Si2O7N2 > La5Si3O12 N,not simply in correlation to the ratio of N3/O2.Excitation and emission spectrum measurements showed the main features of Ce3+ luminescence in the series:the centre of gravity of 5d bands depends on crystal-field splitting more strongly than that on covalency of Ce-N bonding;nephelauxetic effect could not be observed clearly for the investigated series;to some extent Stokes shift was dominated by crystal-field splitting rather than Ce-N covalency degree. 相似文献
927.
目标表面发射率对红外热像仪测温精度的影响 总被引:2,自引:0,他引:2
介绍了红外热像仪测温原理,分析了影响红外热像仪测温精度的因素,计算了不同表面发射率下红外热像仪的测温误差曲线。理论分析表明,目标表面发射率越高,红外热像仪测温精度越高。实验改变表面发射率的设置,计算了不同表面发射率对应的总辐射亮度,得到TP8型长波红外热像仪能够精确测温时,目标表面发射率必须大于0.5的结果。最后,对表面发射率分别为0.96、0.93和0.3的3种材料进行实际测温,结果表明,材料表面发射率较高时,红外热像仪具有较好的测温精度。 相似文献
928.
929.
In the previous paper, we report line strength measurements for 58 bands of 12CO2 between 4550 and 7000 cm−1 [R.A. Toth, L.R. Brown, C.E. Miller, V. Malathy Devi, D. Chris Benner, J. Mol. Spectrosc., this issue, doi:10.1016/j.jms.2006.008.001.]. In the present study, self-broadenedwidth and self-induced pressure shift coefficients are determined in two intervals:
- (a) between 4750 and 5400 cm−1for bands of the Fermi triad (20011 ← 00001, 20012 ← 00001, 20013 ← 00001), three corresponding hot bands (21111 ← 01101, 21112 ← 01101, 21113 ← 01101) and the 01121← 00001 combination band;
- (b) between 6100 and 7000 cm−1 for the Fermi tetrad (30014 ← 00001, 30013 ← 00001, 30012 ← 00001, 30011 ← 00001), two associated hot bands (31113 ← 01101, 31112 ← 01101), as well as 00031 ← 00001 and its hot band 01131 ← 01101.
930.
Antunes A de Rossi W Zezell DM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,64(5):1142-XXXIV
Laser irradiation on hard tissue has produced a resistant surface that is likely to prevent caries. In this study, human enamel and dentine were exposed to nanosecond pulsed Nd:YAG laser with energy densities of 20-40 J/cm(2) and pulse width of 6 ns inducing chemical changes in these tissues. Infrared analysis of human dental enamel and dentine was performed using the KBr method (2mg sample/300 mg KBr). A correlation between non-lased and lased spectra was performed that gives an indication of the changes in organic and inorganic compounds after laser-tissue interaction. Spectra of teeth simultaneously show the inorganic and organic parts of the tissue. The principal bands: amide bands A, I, II, and III from the collagen-matrix, phosphate from the mineral content, and carbonate bands were identified. The normalized area of peak versus peak position was determined. Changes of the bands attributed to the collagen matrix were verified after Nd:YAG irradiation. The present results suggest a chemical modification of organic and mineral compounds by laser. The spectral results indicated an alteration in the absorption bands relative to, essentially, organic compounds. 相似文献