共查询到20条相似文献,搜索用时 62 毫秒
1.
利用电注入着色装置,分别使用点阴极与平板阳极和点阳极与平板阴极在不同条件下对溴化钾晶体进行电注入着色.点阴极注入时,在着色晶体中产生V色心和F色心,计算得到F色心激活能0.84 eV.点阳极注入时,在着色晶体中产生V色心,计算得到V色心激活能0.49 eV.对着色晶体进行系统的光谱测量,确定色心光谱吸收带的光谱参数.对比两种情况下测得的电流~时间关系曲线,解释其色心形成机理. 相似文献
2.
在8组不同的温度和电压条件下,用自行设计的电注入实验装置对氟化钡晶体进行点阴极电注入着色.测试和分析了电注入着色前后氟化钡晶体的吸收光谱.研究结果表明:电注入着色后氟化钡晶体中产生了大量F色心.电注入过程中,F色心首先在阴极注入点附近产生,然后逐渐向阳极扩散.通过测试晶体着色深度并利用F色心迁移率与温度的关系确定出了电注入着色氟化钡晶体中F色心的扩散激活能. 相似文献
3.
4.
5.
6.
7.
利用电注入着色装置,使用点阳极和平板阴极在不同条件下对氯化钠晶体进行电注入着色.在着色晶体中产生大量V、F、胶体C和N心.对着色晶体进行系统的光谱测量,确定色心光谱吸收带的光谱参数.研究不同注入条件对色心浓度的影响.测得电流~时间关系曲线.计算出V色心的激活能小于F色心激活能,进而解释色心形成机理. 相似文献
8.
9.
采用提拉法生长单晶,通过附加金属着色、淬火、室温和液氮温度光聚集等过程,制备了NaCl:(F2^ )H色心激光晶体。研究了NaCl(OH)晶体中色心形成的固态化学反应,结果表明在附加着色过程中发生了热形成、热聚集、热结合和可逆反应,在淬火过程中发生了热分解和可逆反应,在光聚集过程中,发生了光聚集反应、异构化反应和可逆反应。 相似文献
10.
Sr:BaF2晶体电子辐照诱生F型色心及其转型研究 总被引:1,自引:1,他引:0
测试和分析了Sr:BaF2晶体电子辐照前后以及辐照着色的样品光致转型过程的吸收谱.研究结果表明,能量为1.5MeV和1.8MeV的电子束对Sr:BaF2晶体的辐照注量达1015~1016cm-2时,诱生F-H对、F心及其与杂质的复合色心.用波长为632.8nm的He-Ne激光照射电子辐照着色的样品,可使F心转型成FA(Sr2+)心;再用钠光(589.0,589.6nm)照射,又可将FA(Sr2+)心部分回转成F心. 相似文献
11.
Crystallography Reports - The relationship of morphological spectra (sets of data on the morphological types of real polyhedral crystals and their probabilities under current physicochemical... 相似文献
12.
S. S. Batsanov 《Crystallography Reports》2001,46(6):891-897
The evolution of the geometric characteristics introduced by Pauling and their dependence on the specific features of the structure and chemical bonds have been considered. The values of the covalent and van der Waals radii are given as well as their relationships and mutual transitions. 相似文献
13.
Measurements of thermophysical properties of Si melt and supplementary study of X-ray scattering/diffraction by the authors' group were reviewed. The values obtained differed variously from those of literature. Density was 2–3% larger, surface tension 20–30% smaller, viscosity up to 40% larger, electrical conductivity 8% smaller, spectral emissivity more or less in good agreement with literature values, and thermal diffusivity a few percent larger. An anomalous density jump was found near the melting point. Surface tension and viscosity also showed anomaly. A strange time-dependent change of density was observed over 3 h after melting. X-ray analyses suggested a slight change in local atom ordering, but showed no sign of cluster formation. An addition of 0.1 at% gallium caused the density jump to disappear, while that of boron caused no change. An EXAFS study of the former melt indicated a strong interaction between Ga and Si atoms as if molecules of GaSi3 existed. The implications of the measured properties are a possibility of soft-turbulence in an Si melt in a relatively large crucible, a more complicated manner of intake of oxygen depleted molten Si from the free surface region to underneath the growing crystal, and a relaxation of the melt after melting arising from trapped gas species. 相似文献
14.
Within the method of discrete modeling of packings, an algorithm of generation of possible crystal structures of heteromolecular compounds containing two or three molecules in the primitive unit cell, one of which has an arbitrary shape and the other (two others) has a shape close to spherical, is proposed. On the basis of this algorithm, a software package for personal computers is developed. This package has been approved for a number of compounds, investigated previously by X-ray diffraction analysis. The results of generation of structures of five compounds—four organic salts (with one or two spherical anions) and one solvate—are represented. 相似文献
15.
Shibkov A. A. Kochegarov S. S. Denisov A. A. Zolotov A. E. Gasanov M. F. Shuklinov A. V. 《Crystallography Reports》2022,67(2):156-165
Crystallography Reports - Macroscopic jumps of plastic deformation (few percent in amplitude) on creep curves of aluminum–magnesium alloy, caused by a local effect of concentrated solution of... 相似文献
16.
I. Avramov 《Journal of Non》2011,357(22-23):3841-3846
The temperature dependence of viscosity of silicate melts is discussed in the framework of the Avramov–Milchev (AM) equation. The composition is described by means of two parameters: the molar fraction, x, and the “lubricant fraction”, l. The molar fraction is the sum of the molar parts xi of all oxides dissolved in SiO2, the molar fraction of the latter being 1 ? x. It is shown that, with sufficient precision, two of the parameters of the AM equation can be presented as unique functions of the molar fraction. On the other hand, x is not sufficient to determine properly the reference temperature Tr , at which viscosity is ηr = 1013 [dPa.s]. Therefore, additional parameter, “lubricant fraction” l, is introduced. For each of the components, li is a product of molar part xi and a specific dimensionless coefficient 0 ≤ ki ≤ 1 accounting for the specific contribution of this component to the increased mobility of the system. It is demonstrated that, for l > 0, the reference temperature is related to the “lubricant fraction” l through the reference temperature Tr,SiO2 of pure SiO2. 相似文献
17.
V. A. Nepochatenko 《Crystallography Reports》2004,49(5):828-831
Two types of domain-wall equations are analyzed: the equations derived by the Sapriel method and the equations obtained by interface matching of the thermal-expansion tensor. It is shown that, for W-type domain walls, these methods yield the same equations. For W′-type domain walls, the equations obtained by different methods coincide for proper ferroelastics and differ for improper ferroelastics. 相似文献
18.
Crystal chemical characteristics of the α and β modifications of Zn2V2O7 are calculated based on in situ high-temperature X-ray measurements. The expansion of the structure is found to be strongly anisotropic up to the negative volumetric thermal expansion of the α-Zn2V2O7 unit cell in the temperature range of 300–600°С, α V =–17.94 × 10–6 1/K. The transformations of the “hard” and “soft” sublattices with an increase temperature and at the phase transition are considered in detail. It is shown that the negative volumetric thermal expansion of α-Zn2V2O7 is due to the degeneracy of the zigzag-like shape of zinc–oxygen columns at constant distances between their vertices. 相似文献
19.
SAXS in situ experiments on the evolution of TMOS solutions during hydrolysis and polycondensation lead to power laws with scaling exponents ≈ 2. It is suggested that this could be the result of the polydispersity of the samples and that only an apparent fractal dimension can be obtained in this way. Kinetic studies tend to indicate that agglomeration in the sol is the result of a diffusion-controlled process. 相似文献