564 resultados para AC-2


Relevância:

30.00% 30.00%

Publicador:

Resumo:

A series or Ta2O5 films with different SiO2 additional layers including overcoat, undercoat and interlayer was prepared by electron beam evaporation under the same deposition process. Absorption of samples was measured using the surface thermal lensing (STL) technique. The electric field distributions of the samples were theoretical predicted using thin film design software (TFCalc). The laser induced damage threshold (LIDT) was assessed using an Nd:YAG laser operating at 1064 nm with a pulse length of 12 ns. It was found that SiO2 additional layers resulted in a slight increase of the absorption, whereas they exerted little influence on the microdefects. The electric field distribution among the samples was unchanged by adding an SiO2 overcoat and undercoat, yet was changed by adding an interlayer. SiO2 undercoat. The interlayer improved the LIDT greatly, whereas the SiO2 overcoat had little effect on the LIDT. (C) 2007 Elsevier Ltd. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Influence of ZrO2 in HfO2 on the reflectance of HfO2/SiO2 multilayer at 248 nm was investigated. Two kinds of HfO2 with different ZrO2 content were chosen as high refractive index material and the same kind of SiO2 as low refractive index material to prepare the mirrors by electron-beam evaporation. The impurities in two kinds of HfO2 starting coating materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum (GDMS) technology and secondary ion mass spectrometry (SIMS) equipment, respectively. It showed that between the two kinds of HfO2, either the bulk materials or their corresponding films, the difference of ZrO2 was much larger than that of the other impurities such as Ti and Fe. It is the Zr element that affects the property of thin films. Both in theoretical and in experimental, the mirror prepared with the HfO2 starting material containing more Zr content has a lower reflectance. Because the extinction coefficient of zirconia is relatively high in UV region, it can be treated as one kind of absorbing defects to influence the optical property of the mirrors. (C) 2008 Elsevier B.V. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Nb2O5 sculptured thin. films deposited by electron beam evaporation with glancing angle deposition were prepared. Nb2O5 sculptured thin. films with tilted columns are optical anisotropy. XRD, SEM, UV-vis-NIR spectra are employed to characterize the microstructure and optical properties. The maximum of birefringence (Delta n) is up to 0.045 at alpha = 70 degrees with packing density of 0.487. With increasing the deposition angle, refractive index and packing density of Nb2O5 STF are decreasing. The relationship among deposition parameter, microstructure and optical properties was investigated in detail. (C) 2008 Elsevier B. V. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Relevância:

30.00% 30.00%

Publicador:

Relevância:

30.00% 30.00%

Publicador:

Relevância:

30.00% 30.00%

Publicador:

Resumo:

1、红树科和海桑科是中国植物志的一部分,1980年开始编著,1983年出版,本文记载红树科6属13种1变种,6属中除山红树属和竹节树属是内陆种类,其余4属均是组成红树林的主要树种,红树科的木杬属、角果木属、秋茄树属和红树属它们的树皮都含有丰富单宁为侵染皮革和染料的主要原料,又是防风防浪护堤的海岸防护林的主要树种及盐土指示植物,木材大都坚硬,纹理密微,在药用方面有止痛等作用。海桑科与红树科的生态习性极为相似也是构成红树林的主要树种和海岸防林不可缺少的种类,本文记载中国有2属4种。以上两科均详细叙述它们的形态、生态习性和经济用途。2、通过研究多年搜集的标本和资料,报导石榴科和玉蕊科的种类、分布和经济用途。石榴原产地中海沿岸至伊朗及其邻近地区,汉时张骞出使西域引入我国栽培,是我国第一批有文字记载的外来经济树种之一,既可食用和药用,又供观赏,综述历代文献,描述其形态演变,对研究外来(特别是地中海沿岸)经济植物的驯化有重要的意义。玉蕊科是有代表性的热带植物群,我国种类虽不多,但其发现对论证我国植物区系的热带亲缘的理论提供了直接的证据,故有一定的科学意义。

Relevância:

30.00% 30.00%

Publicador:

Relevância:

30.00% 30.00%

Publicador:

Relevância:

30.00% 30.00%

Publicador: