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961.
We obtained thin films of the Bi4Ge3O12, Bi4Si2O12, PbWO4, and Bi2WO6 scintillators and investigated their luminescence properties on xray excitation. We measured the xray luminescence spectra and established the linear character for the dependence of the luminescence intensity on the power of the dose of xray irradiation within the limits of up to 3·10–3 A/kg. We investigated the radiation stability of the films obtained. The possibility of their application for detecting ionizing radiation is investigated. The films based on Bi4Ge3O12 with an admixture of the Ge and Si or Mn activator of up to 1.5 mol.% are most suitable. 相似文献
962.
Xiaoli Li Guangmin Wu Jun Shen Fan Yang Jue Wang 《Journal of Sol-Gel Science and Technology》2002,25(3):235-242
When designing a cut-off interference filter, extra layers are needed to add on each side of periodic symmetrical multilayer to match the incident medium and the substrate. In this paper, we use sol-gel film with adjustable refractive index as the match layer. The influence of the refractive index and thickness of the match layer on the film system is discussed in detail. As an example, a special filter which is transparent (>80%) at the wavelength 3–5 m and high reflective (>90%) at the wavelength 1.3 m is designed. Finally a series of optimized film parameters are presented. The whole design process is a good reference to the other multilayer special filter made by sol-gel process. 相似文献
963.
Heteroatom polysilylenes with Cl, OR and NR2 substituents attached to the silicon chain through the heteroatom are described. The relationship between the single crystal X-ray structures of octachlorocyclotetrasilane Si4Cl8 and perchloropolysilylene, (SiCl2)n, is discussed with reference to possible mechanisms for its phototopochemical synthesis from Si4Cl8. Substitution with alcohols yields the bis(alkoxy)polysilylenes, and the origin of the red-shifted UV spectra are discussed in terms of the electronic interaction between oxygen n and silicon orbitals. Substitution with secondary amines yields soluble, yellow polymers with even longer wavelength UV absorption maxima. Effects of the alkyl chain length on hydrolytic stability are considered. 相似文献
964.
Jin ZHAI Feng Lian BAI Qing Guo HE Ying Shun LI Lei JIANG Tong LIN Organic Solid Laboratory Research Center for Molecular Sciences Institute of Chemistry The Chinese Academy of Science Beijing 《中国化学快报》2000,11(9)
The hotSPOt in the fields of molecular films focuses on highly ordered, ultrathin filmswith molecularly controllable surface properties. It is attractive tO stUdy supramolecularfunctional POlymeric materials with suitable physical properties and abilities to formorganized superstrUctures at the interfacesl'2'3A. Dendritic macromolecules are a kind ofmaterials which is capable of self-organizing into superstrUctUres'. So a new dendrimerlike POly(Phenylene vinylene)- --hyperbranched conj "… 相似文献
965.
Z. H. Mkhitaryan A. A. Shatveryan V. M. Aroutiounian F. V. Gasparyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2008,43(3):131-135
Low-frequency noise, in the range 1–500 Hz, is measured at room temperature in samples of Au/PS/SCS/Al structure with a layer of porous silicon. Numerical values of the Hooge parameter αH are estimated and the dependence of αH on the composition of the gaseous environment, where the sample is placed, is determined. Possible reasons of observed high values of αH for the samples in air and of the increase in αH in conditions of gas adsorption are discussed. Introducing of carbon oxide in air changes the shape of spectrum. 相似文献
966.
967.
Two series of samples were investigated: a) aluminum films with a sublayer of tantalum; b) industrial aluminum alloys AMg-2m;
D16; AMc; AD-1n. The optimum composition of re-anodizing electrolyte was chosen on the basis of a solution of citric acid
and ethylene glycol. The results of investigations of the sparking voltage at re-anodizing for various aluminum alloys and
thicknesses of primary porous oxide are presented. The analytical dependence of breakdown voltage value on forming voltage
value for alloy AD-1n was obtained. The original design of re-anodizing cell allowing increase of the sparking voltage was
developed. 相似文献
968.
Roland Hunt 《国际流体数值方法杂志》1992,14(5):539-556
The numerical solution of the thin film flow surrounding a horizontal cylinder resulting from a single vertical cylindrical jet is obtained. This is effected by transforming the domain of the flow, which contains a free surface, onto a rectangular parallelepiped and using a marching strategy to solve the ensuing parabolic equations. The flow terminates at a finite distance along the cylinder, its position depending on the velocity and mass flux of the jet. A comparison with the usual two-dimensional model in which the jet is replaced by a vertical sheet shows that such a representation is valid provided the overall width of the flow is not too large. In particular, the differences in heat transfer characteristics amount to a few per cent, thus validating the use of the two-dimensional model when applied to heat exchanger tubes. A comparison with the more usual multicolumn case is also considered. 相似文献
969.
磁控溅射制备ZnO薄膜的受激发射特性的研究 总被引:2,自引:0,他引:2
用射频磁控反应溅射法在二氧化硅衬底上制备ZnO薄膜。得到了在不同温度下ZnO薄膜的吸收与光致发光。观测到了纵光学波 (LO)声子吸收峰与自由激子吸收峰 ;室温 (30 0K)下 ,PL谱中仅有自由激子发光峰。这些结果证实了ZnO薄膜具有较高的质量。探讨了变温ZnO薄膜的发光特性。研究了ZnO薄膜的受激发射特性。 相似文献
970.
本文分析了经典分子动力学(Molecular Dynamics)技术在模拟厚度在纳米量级的单晶硅薄膜平行于薄膜平面方向的热导率时出现的用难,指出精确计算薄膜表面附近处的原子运动状态对于单晶硅纳米薄膜面向热导率的分子动力学模拟具有重要意义,并在此基础上提出采用基于分子动力学和预处理共轭梯度法(Preconditioned conjugate Gradients)的Ab Initio方案模拟面向热导率。 相似文献