Crystal structure and optical absorption investigations on β-In2S3 thin films

The crystal structure of annealed β-In₂S₃ thin films with different thickness was investigated by X-ray diffraction technique. Lattice parameters, crystallite size and microstrain were calculated. It was found that the lattice parameters are independent on film thickness, while annealing temperatures increase them. Crystallite sizes were increased with the increase of the film thickness and improved by annealing temperatures. In all cases, the microstrains were decreased gradually with the increase in both film thickness and annealing temperatures. Optical properties of β-In₂S₃ thin films were performed in the spectral range from 400 to 2500 nm to determine the optical constants (n and k), the high frequency dielectric constant, ε_∞, the lattice dielectric constant, ε_L, and the energy gap. The optical constants were found to be independent on film thickness in the range from 200 to 630 nm. The high frequency dielectric and lattice dielectric constants of the as-deposited film increased by annealing temperatures. The energy gap for the as-deposited In₂S₃ was found to be 2.60 eV and increased to 2.70 and 2.75 eV by annealing at 423 and 473 K for 1 h, respectively.     

Infrared spectroscopic ellipsometry and atomic force microscopy study of plasma polymerized hexamethyldisiloxane layers post-treated by NH3 plasma

Hexamethyldisiloxane polymer layers obtained at low frequency glow discharge were post-treated by ammonia vapours under the same plasma conditions. Infrared spectroscopic ellipsometry and atomic force microscopy studies were carried out with the aim to elucidate the structural and morphological changes accompanying this modification. The infrared ellipsometry combined with best-fit calculations was used to evaluate the optical constants of the polymer film before and after the treatment, and thus to provide data for the vibrational band analysis. No additional modified layer due to the plasma treatment was detected, but a newly emerged weak band at 1562 cm⁻¹ was observed in the ellipsometric spectra of the ammonia-treated sample, which was ascribed to N-H deformation in amines.The surface morphology was imaged by atomic force microscopy. The data revealed that the NH₃ treatment had caused distinct micro-structural modification on the top layer surface. The size of the nodule aggregates was largely reduced and this contributed to a much better developed top surface.     

Dispersive optical constants of thermally deposited AgIn5S8 thin films

AgIn₅S₈ thin films were obtained by the thermal evaporation of AgIn₅S₈ crystals onto ultrasonically cleaned glass substrates. The films are found to exhibit polycrystalline cubic structure. The calculated lattice parameter of the unit cell (a) is 10.78 Å. The transmittance data of the as grown films which was recorded at 300 K in the incidence wavelength (λ) range of 320-1000 nm are used to calculate the refractive, n(λ). The transmittance and reflectance data are also used to calculate the absorption coefficient of the as grown AgIn₅S₈ thin films. The fundamental absorption edge is found to be corresponding to a direct allowed transitions energy band gap. This band-to-band transition energy is found to be 1.78 eV and it is consistent with that reported for AgIn₅S₈ single crystals.     

Plasma influence on the properties and structure of indium tin oxide films produced by reactive middle frequency pulsed magnetron sputtering

Reactive pulsed magnetron sputtering was used to produce conductive and transparent tin-doped indium oxide (ITO) films with low thickness inhomogeneity. Due to the parallel operation of two magnetrons, the deposition system allows in situ investigations of the plasma influence on the film properties. The distribution of the film resistivity, refractive index, structure and stoichiometry along the substrate are presented and related to the spatial distribution of the plasma flow escaping the magnetrons, and the substrate temperature. A higher plasma flow likely causes a localized relaxation of the distorted In-O bonds in amorphous phase which prevails in ITO films prepared at unheated substrates. This leads to a decrease of the film resistivity due to free electrons density and mobility enhancement. The free electron density increase is caused likely by generation of oxygen vacancies. Deposition on a heated substrate (T_s / T_m = 0.3) leads to a change of the film growth mode due to enhanced surface diffusion of the adatoms which results in a textured low resistivity film. This also causes significant improvements of the homogeneity of the film properties that is important for ITO applications.     

论温词景物描写的功能

温庭筠词中有大量的景物描写,对这些景物描写的功能,人们常常认识不足。实际上,温庭筠描写景物的目的并不单单为了“炫人眼目”,而是为表现词作主人公的内心情感服务的,其功能表现为三种形态：一是景与情融,起的是借景传情的作用;二是景与情同,起的是渲染作用;三是景与情反,起的是的衬作用。无论何者,都服务于词作主人公情感的传达和心理的揭示,绝不应受到“浪费丽字”的诟病。     

First-principles study on electronic structures and absorption spectra for BaWO4 crystal containing barium vacancy

The electronic structures, dielectric function and absorption spectra for the perfect BaWO₄ (BWO) crystal and the BWO crystal containing barium vacancy () have been studied using density functional theory code CASTEP with the lattice structure optimized. The results indicate that the optical properties of the BWO crystal exhibit anisotropy and its optical symmetry coincide with lattice structure geometry of the BWO crystal. For the BWO crystal containing , there exhibit four absorption bands peaking at 0.71 eV (1751 nm), 1.85 eV (672 nm), 3.43 eV (362 nm) and 3.85 eV (322 nm), respectively. The origins of the 370 nm absorption band should be related to the .     

Vacuum-system design for the large-scale cryogenic gravitational wave telescope

The large-scale cryogenic gravitational wave telescope (LCGT) requires ultra-high vacuum tubes which the laser beams pass through. Two 3-km vacuum tubes are kept in ∼10⁻⁷ Pa of vacuum pressure so as to reduce scattering-effects due to residual gas molecules. The stainless-steel material with electro-chemical buffing is the most available for use as long tubes of 1 m in diameter. To reduce noises due to scattered light from the surface of tubes, a lot of baffles are inserted into the tubes.     

论地域文化对宋词创作之影响

地域化因素是影响学创作的重要外部因素,是无数人创作灵感的源泉．宋代地域化在中国化史具有突出的特色,对宋词创作产生了多层面的影响,其主要表现为：地域化对宋词繁荣起了推动作用;东南地区地域化的迅速发展,使得词人创作队伍集聚于江西、江苏、浙江等地;地域化从自然地理环境与人地理环境两个方面对词人创作风格产生重大影响;不同的地域化会促使同一词人创作风格的转变．     

基于主题模型的古典乐器诗词文本挖掘

古代先贤将乐器按其制作材料分为八类,《周礼·春官·大师》中记载“皆播之以八音: 金石土革丝木匏竹。”该文将《全唐诗》、《全宋词》中有关“八音”的诗句、词句作为研究对象,使用基于LDA和NMF的主题挖掘、基于Author-Topic-Model的作者相似度计算等方法。从宏观到微观,从整体诗词到具体诗人/词人,从主题的聚类、动词形容词的抽取到具体诗人词人作品相似度的计算,多维度、多层次、多角度研究了唐诗宋词中的中国古典乐器。