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1.
A.L. Pan H.G. ZhengZ.P. Yang F.X. Liu Z.J. Ding Y.T. Qian 《Materials Research Bulletin》2003,38(5):789-796
Small Ag particles or clusters dispersed mesoporous SiO2 composite films were prepared by a new method: First the matrix SiO2 films were prepared by sol-gel process combined with the dip-coating technique, then they were soaked in AgNO3 solutions followed by irradiation of γ-ray at room temperature and in ambient pressure. The structures of these films were examined by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and optical absorption spectroscopy. It has been shown that the Ag particles grown within the porous SiO2 films are very small, and they are isolated and dispersed from each other with very narrow size distributions. With increasing the soaking concentration and an additional annealing, an opposite peakshift effect of the surface plasmon resonance (SPR) was observed in the optical absorption measurements. 相似文献
2.
Peter V. Sushko Alexander L. ShlugerKatsuro Hayashi Masahiro HiranoHideo Hosono 《Thin solid films》2003,445(2):161-167
Recently it has been discovered that a nano-porous main group oxide 12CaO·7Al2O3 (C12A7) can be converted from a wide-gap insulator to a good transparent conductor. Using ab initio modelling we explain good conductivity of this material by very small barriers for hopping of localised electrons between neighbouring positive cages. We show that optical absorption of C12A7 in infrared region and at energies higher than 2.7 eV is due to inter-cage and intra-cage electron transitions, respectively. The proposed mechanisms can be useful in further search for conducting transparent media. 相似文献
3.
Salvatore Lombardo Salvatore Ugo Campisano 《Materials Science and Engineering: R: Reports》1996,17(8):739-336
We have investigated the relationship between microstructure and electrical conductivity in semi-insulating polycrystalline silicon (SIPOS) with oxygen concentrations in the 2–35 at.% range and the effect of doping with boron, phosphorus, arsenic and erbium by ion implantation. SIPOS thin films are mixtures of silicon and silicon oxide phases. The chemical and morphological evolution of these phases upon annealing is emphasized. Electrical conductivity measurements are interpreted in terms of a physical model containing few free parameters related to the material microstructure. A direct extension of this model explains also the conductivity increase in SIPOS doped with elements of the third or the fifth group. In the last part of the paper, data of electroluminescence at 1.54 μm in Er-implanted SIPOS due to intra-4f transitions of the Er3+ ion are shown and discussed. 相似文献
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先说明市内接入网的单位用户和住家用户两大类使用通信和电视、交互型和分配型业务的要求不相同,相应地对光纤传输的应用须作不同的考虑,文中认为;光纤从市内交换局直连办公大楼是合乎现实需要的,而对于居民住家,宜选用光纤连至路边或光纤与同轴结合和适当利用无源光网络等方案,俟将来时机成熟才实行光纤连至每一家,文末有概括总结,说明接入网不同于长途网,接入网的光纤系统可以使用常规单模光纤,工作于波长1.3μm,而光放大器和波分多路系统不是普遍需要,但光电子集成在光端机中是必要的。 相似文献
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A theory is presented that explains how the visual system infers the lightness, opacity, and depth of surfaces from stereoscopic images. It is shown that the polarity and magnitude of image contrast play distinct roles in surface perception, which can be captured by 2 principles of perceptual inference. First, a contrast depth asymmetry principle articulates how the visual system computes the ordinal depth and lightness relationships from the polarity of local, binocularly matched image contrast. Second, a global transmittance anchoring principle expresses how variations in contrast magnitudes are used to infer the presence of transparent surfaces. It is argued that these principles provide a unified explanation of how the visual system computes the 3-D surface structure of opaque and transparent surfaces. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
H. Luo 《Microsystem Technologies》2006,12(4):324-329
This paper focuses on tracking, reconstruction and motion estimation of a well-defined MEMS optical switch from a microscopic
view. For out-of-view reconstruction, a homography capable of transforming feature points and feature lines between a microscopic
image and a CAD model of the switch is implemented. The homography between two sequential microscopic images is decomposed
and factorized for motion estimation. Optical flow has also been explored to provide rough estimations of rotation centre
and angle. The paper also illustrates motion parameter optimization principles to deal with uncertainty inherent in micro
world. After non-linear optimization, estimation accuracy for rotation angle and rotation centre can reach 0.06° and pixel
level, respectively. 相似文献
9.
In optical microscopic measurement of internal blood-vessel diameters, the effect of refraction must be taken into account to ensure accuracy of the result. This effect is discussed and an analytical correction formula derived. Phantom blood vessels with known internal and external diameters were used to test the validity of the correction formula. The errors obtained prior to correction were reduced significantly after correction. 相似文献
10.
利用引进的制造技术和设备,制作出了 APT(STLRI)—1.78型系列化光纤连接器。 相似文献