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用三台可调谐脉冲染料激光器三步共振电离方法,测量铀原子在电离限附近的能级。测量了在49733-50224cm^-1能量区的40余个能级位置。 相似文献
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为研究ZnSe中的本征缺陷和A1在ZnSe中的深能级行为,首先测量了Znse单晶体中的深能级,发现只存在Ec-0.33eV一个电子陷阱。然后,通过热扩散的方法,在300℃~700℃温度范围内把A1掺杂到ZnSe单晶体中,结果发现存在Ec-0.33eV和Ec-0.70eV两个电子陷阱。本文从缺陷化学角度对ZnSe中的本征缺陷和Ec-0.70eV深能级的结构及起源进行了讨论。 相似文献
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关于ZnSe—ZnS应变超晶格P型导电机理的探讨 总被引:1,自引:0,他引:1
本文利用变温Hall测量,证实了我们用MOCVD法生长的No.87—39A ZnSe-ZnS应变超品格(SLS)具有P型导电特性。文中试图从应变超晶格的临界厚度,电学参数、能带结构等方面解释ZnSe-ZnS SLS反型的原因。文中指出,这时的受主能级可能处于ZnS层靠近界面附近,这些受主能级的位置比ZnSc阱中满带顶能量低。 相似文献
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用激光共振电离光谱测定铈原子奇宇称高激发态(Ⅰ):32 042~34 575 cm-1 总被引:2,自引:0,他引:2
激光共振电离光谱是一种十分适合于高能量区重元素复杂原子结构研究的技术。为寻找原子最佳的共振电离通道,利用这一技术对铈原子奇宇称高激发态进行了研究。在32042-34575cm^-1范围内,用两步共振激发和非共振电离方法,首次观察到了83条铈原子奇宇称高激发态能级,测量了这些新能级的能量和给出了可能的总角动量J值。 相似文献
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测量了元素和化合物半导体单晶材料的常温、低温下的表面光电压,推导了有关计算公式,计算得出材料的少子扩散长度、深能级和表面能级位置,禁带宽度和化合物组分;由双能级复合理论,研究了少子扩散长度与深能级的关系,计算了深能级浓度和参数;计算结果与其他方法的测量实验值基本一致.
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Sambhu N Datta 《Pramana》1993,41(4):345-362
A set of indigenously developed computer programs for ab-initio Hartree-Fock calculations on both closed- and open-shell molecules
have been described. These programs have been written for calculations using GTO basis sets. Integral formulae have been taken
from Taketaet al [8]. Structures and functions of the programs have been discussed. These programs have been extensively tested. Molecular
integrals over GTO basis sets have been chosen for tests and as numerical examples in this paper. Results of calculations
using very accurate minimal bases have been given for methane. Time taken for these computations in a CDC Cyber 180/840 machine
has been indicated. Trends in the calculations have also been illustrated by employing 4-gaussian expansions for the STO’s
and by varying the basis size for LiH and BH+.
An erratum to this article is available at . 相似文献
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IGCC空气侧整体综合优化的研究 总被引:4,自引:1,他引:3
主要符号表X。。氮气回注系数如空分整体化系数E。;c燃气轮机压气机效率G。l回注氮气流量万燃气轮机透平前温尼。”系统相对效率G。。煤气氮气掺混流量Ea;,c空气专用压缩机效率N。”系统相对功率1前言整体煤气化联合循环(IGCC)系统模拟与优化逐步受到重视,开展了许多相关研究[‘-‘]。但是,现有的方法[‘,‘]一个突出的问题,它是在设定的具体流程方案下的数值分析,这常常导致落入“局部优化掩盖了整体最优”的误区。本文是研究以空分系统为中心的空气侧子系统的整体优化,阐述基本概念,尝试新方法,并结合大型商业化装… 相似文献
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A. L. Stroyuk A. E. Raevskaya A. V. Korzhak S. Y. Kuchmii 《Journal of nanoparticle research》2007,9(6):1027-1039
Formation of zinc sulfide nanocrystals in aqueous solutions of various polymers has been studied. Spectral properties of ZnS
nanoparticles have been investigated, the structure of the long-wave edge of the fundamental absorption band of ZnS nanocrystals
has been analyzed. It has been shown that the variation of the synthesis conditions (stabilizer nature and concentration,
solution viscosity, ZnS concentration, etc.) allows tailoring of the ZnS nanocrystals size in the range of 3–10 nm.
Photochemical processes in colloidal ZnS solutions, containing zinc chloride and sodium sulfite, have been investigated. It
has been found that the irradiation of such solutions results in the reduction of Zn(II), the rate of this reaction growing
at a decrease in the size of ZnS nanoparticles. Kinetics of photocatalytic Zn(II) reduction has been studied. It has been
concluded that two-electron reduction of adsorbed Zn(II) species is the rate-determining stage of this reaction.
Photocatalytic activity of ZnS nanoparticles in KAu(CN)2 reduction in aqueous solutions has been discovered. Spectral characteristics and kinetics of ZnS/Au0 nanocomposite formation have been studied. It has been shown that the photoreduction of gold(I) complex is the equilibrium
reaction due to the reverse oxidation of gold nanoparticles by ZnS valence band holes. 相似文献
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本文对实验室条件下拍摄黑白艺术肖像的方法作了探讨,对放大相片的方法作了改进,给出了实验数据,并对拍摄结果作了分析和讨论。实验获得了放大尺寸的人物肖像艺术照片。 相似文献
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Summary Cross-linked polystyrene-bound and poly(ethylene glycol)-bound phase-transfer catalysts as well as homopolymers of cinchona
alkaloid derivatives have been synthesised. Both soluble and insoluble polymers have been investigated. The enantioselective
alkylation of N-diphenyl methylene glycine t-butyl ester has been successfully carried out in heterogeneous and homogeneous systems. High enantioselectivities (up to
96%) have been obtained. The polymer-bound catalysts have been easily recovered and conditions for efficient recycling have
been studied. 相似文献
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The hybridizations of a graphene layer by a thymine and a uracil nucleobase have been investigated by performing density functional theory (DFT) calculations. The isolated and hybrid structures have been firstly stabilized to reach the minimum energy and the electronic properties have been subsequently evaluated for the optimized structures. The structural and atomic scale parameters indicated that the tip of graphene is important in determining the properties of new hybrids. Moreover, different effects of thymine and uracil nucleobases have been identified in the hybrid structures. Quadrupole coupling constants have been evaluated to characterize the atomic scale properties, in which the most notable effects of hybridizations have been observed for the atoms close to the linking regions whereas negligible effects have been seen for other atoms. 相似文献
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Composite ZnO/Ag nanoparticles have been formed via the photocatalytic reduction of silver nitrate over the ZnO nanocrystals,
their optical, electrophysical and photochemical properties have been investigated. Mie theory has been applied to analyze
the structure of the absorption spectra of ZnO/Ag nanocomposite. The irradiation effects upon the optical properties of ZnO/Ag
nanostructure have been investigated. It has been found that the irradiation of ZnO/Ag nanoparticles results in electrons
accumulation by both the semiconductor and the metallic components of the nanocomposite. It has been found that silver nitrate
can be photochemically deposited onto the surface of ZnO nanoparticles under the illumination with the visible light in the
presence of the sensitizer – methylene blue. Kinetics of the sensitized Ag(I) photoredution has been studied. It has been
concluded that the key stage of this process is the electron injection from singlet-excited methylene blue molecule into ZnO
nanoparticle. 相似文献
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丝蛋白分子的红外光谱研究 总被引:3,自引:1,他引:2
本文记录并研究了桑蚕丝、柞蚕丝、天蚕丝和天柞杂交蚕丝等几类共42种蚕丝样品的红外光谱,确定了柞丝类和桑丝类两大类蚕丝样品在红外光谱方面的差别。从而为鉴别蚕丝样品的种类建立起一种简便易行的方法。通过对各类样品的红外光谱数据处理,计算了某些谱带的相对强度比,获得了一些半定量的规律性结果。 相似文献
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Three phase transitions between 100 and 400 K were previously shown by X-ray diffraction measurements. Such results have been confirmed by optical measurements on crystals. The thermal dependence of the birefringence has been determined. A new phase transformation has been shown at around 590 K not only by optical study but also by dielectric measurements. Ferroelastic domain-walls have been visualized. The sequence transition has been discussed taking into account the various space groups. 相似文献