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171.
研究一维半导体在外电磁场中的光吸收、涉及电子带间的直接跃迁与间接跃迁,考虑了电子-空穴相互作用的激子光吸收,导出一维半导体的光吸收系数公式。 相似文献
172.
A quick sample preparation method was used for the determination of sulphur and trace metals in oil and oily products by the ICP with a minitorch. Stable aqueous emulsions of oils and oil products were made by using two kinds of emulsifiers (one with low sulphur content, the other sulfonated). Aqueous standard solutions can be used for the preparation of calibration solutions. The contents of S, Al, Cr, Cu, Fe, Mg, Ni and Pb in aqueous emulsions were determined and the results were in good agreement with the composition of oil standard solutions used for control analysis procedure. 相似文献
173.
Pyrolysis ammonia chemical ionization (PyCI) mass spectrometry was performed on hy-droxyethyl-, hydroxypropyl-,methyl-, hydroxypropylmethyl-, and ethylhydroxyethyl cel-luloses. The mass peaks in the PyCI mass spectra of these cellulose ethers could be assigned to the ions of pyrolytic dissociation products which form via the [2 + 2 + 2] cycloreversion and the Ei elimination pyrolysis pathway. Structural information about the residual amount of nonderivatized cellulose, the relative chain length distributions of the substituents in hydroxyalkyl celluloses, and the end-capping of hydroxyalkyl substituents by alkyl groups in the mixed cellulose ethers is obtained. Interference of secondary pyrolysis products in the PyCI mass spectra is found to be of minor importance, especially in the lower mass regions. © 1995 John Wiley & Sons, Inc. 相似文献
174.
We have used electronic spectroscopy in the 160–1100 nm range to study the polyvinyl alcohol-nickel(II) chloride system. Based
on the results obtained, we hypothesize formation of mixed-ligand complexes of the type [Ni(H2O)6-nCln]2-n (n = 0, 1,..., 5) in the polyvinyl alcohol matrix. Transformation of the coordination sphere as the NiCl2 concentration changes is apparent both in the region of the d-d transition bands (350–1100 nm) and in the region of the charge
transfer bands (160–250 nm). We propose assigning the absorption bands separated by mathematical treatment to complexes of
specific compositions.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 136–138, January–February, 2006. 相似文献
175.
Stefanie M. Walz Thomas E. Malner Ulrich Mueller Rolf Muelhaupt 《Journal of Polymer Science.Polymer Physics》2003,41(4):360-367
We explored phase separation and self‐assembly of perfluoroalkyl segments at the surface of polymer films obtained from latices of semifluorinated acrylate copolymers and the corresponding latex blends of nonfluorinated and semifluorinated polyacrylates. With laser‐induced secondary mass spectrometry the fluorine distribution was measured after annealing above the minimum film‐forming temperature of the polymers up to a depth of several micrometers. Depth profiles of a semifluorinated acrylate homopolymer and latex blends thereof with fluorine‐free alkylacrylates with 25, 50, and 75 mol % semifluorinated acrylate as well as a copolymer comprised of alkyl acrylate and semifluorinated acrylate (50/50 mol %) were investigated. In the case of latex blends containing both semifluorinated polyacrylates and fluorine‐free or low‐fluorine polymers, self‐assembly accounted for enrichment of the perfluoroalkyl segments at the surface. Coatings exhibiting low surface energy and having a substantially reduced total fluorine content were obtained. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 360–367, 2003 相似文献
176.
177.
R. Rehm M. Walther J. Schmitz J. Fleißner F. Fuchs J. Ziegler W. Cabanski 《Opto-Electronics Review》2006,14(1):19-24
The first fully operational mid-IR (3–5 μm) 256×256 IR-FPA camera system based on a type-II InAs/GaSb short-period superlattice
showing an excellent noise equivalent temperature difference below 10 mK and a very uniform performance has been realized.
We report on the development and fabrication of the detecor chip, i.e., epitaxy, processing technology and electro-optical
characterization of fully integrated InAs/GaSb superlattice focal plane arrays. While the superlattice design employed for
the first demonstrator camera yielded a quantum efficiency around 30%, a superlattice structure grown with a thicker active
layer and an optimized V/III BEP ratio during growth of the InAs layers exhibits a significant increase in quantum efficiency.
Quantitative responsivity measurements reveal a quantum efficiency of about 60% for InAs/GaSb superlattice focal plane arrays
after implementing this design improvement.
The paper presented there appears in Infrared Photoelectronics, edited by Antoni Rogalski, Eustace L. Dereniak, Fiodor F. Sizov, Proc. SPIE Vol. 5957, 595707 (2005). 相似文献
178.
Tamara Elzein Virginie Kreim Achraf Ghorbal Sophie Bistac 《Journal of Polymer Science.Polymer Physics》2006,44(22):3272-3281
Friction‐deposited layers of atactic polystyrene (PS) on inert and OH‐grafted gold substrates were the subject of this study to establish a relationship between the friction process and the resulting anisotropy of the transferred polymer chains. We show, by using polarization‐modulation infrared reflection‐absorption spectroscopy that the deposited PS chains involve an anisotropy in which PS main backbone is rather perpendicular to the friction support, fact that is surprising when compared with the majority of polymers where the anisotropy is along the sliding direction. Moreover, our calculation of the orientation angles revealed that PS chains are more perpendicular in the transferred layers than in spin‐coated films. This particular anisotropy is probably due to a parallel reorientation of the phenyl ring on the friction support whatever the surface chemistry is. On the other hand, this study was useful to rectify the assignment of infrared bands unclearly reported in the literature. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3272–3281, 2006 相似文献
179.
太赫兹半导体探测器研究进展 总被引:4,自引:0,他引:4
太赫兹(THz)探测器是THz技术应用的关键器件之一.基于半导体的全固态THz量子阱探测器(THzQWIP)具有探测响应速度快、制作工艺成熟、体积小和易集成等优点.文章简要介绍了THz探测器的分类和特点,重点介绍了THzQWIP的工作原理和研究进展. 相似文献
180.
Ligia E. Zamora G. A. Perez Alcazar J. M. Greneche S. Suriñach 《Hyperfine Interactions》2006,168(1-3):1057-1063
Fe60Mn10Al20Nb10, (Fe60Mn10Al30)95Nb5 and (Fe60Mn10Al30)90Nb10 ball milled powdered alloys were investigated using X-ray diffraction, Mössbauer spectrometry, thermomagnetic (TGM) and magnetization measurements. We studied the influence of Nb content and of different milling times on the structural and magnetic properties. Two main features can be concluded: (1) the FeAlMn induces a BCC phase whatever the Nb content is, and (2) as both increasing Nb content and milling time give rise to an highly disordered state in conjunction with a decrease of the ferromagnetic behavior. 相似文献