共查询到20条相似文献,搜索用时 421 毫秒
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光子晶体是一种周期性电介质材料,具有光子带隙和光子局域等一系列优异的光学特性。制备了多种不同直径的单分散二氧化硅胶体微球,采用垂直沉积法将不同直径,以及同一直径不同浓度的二氧化硅胶体微球自组装成多种光子晶体薄膜,并用扫描电子显微镜和紫外—可见—近红外分光光度计对其微观结构和光学特性进行了表征,结果表明所得晶体薄膜具有三维有序结构,其表面存点、线缺陷。自组装得到的光子晶体薄膜存在明显的光子带隙特征,带隙位置与二氧化硅胶体微球直径有关,带隙中心波长与理论值一致。随着二氧化硅胶体微球浓度的增加,光子带隙深度增加,特性更好,但是,当浓度大于10%时,光子带隙的深度反而减小。 相似文献
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利用Sol-Gel的方法制备了多孔二氧化硅薄膜。通过优化薄膜制备工艺,实现了多孔二氧化硅薄膜厚度在450nm~3000nm范围内可控,薄膜孔率为59%。用FTIR光谱分析了不同热处理温度下多孔二氧化硅薄膜的化学结构。研究了多孔二氧化硅薄膜的介电常数、介电损耗、漏电流等电学性能,结果表明多孔二氧化硅薄膜本征的介电常数为1.8左右,是典型的低介电常数材料。并通过原子力显微镜对薄膜的表面形貌进行了表征。 相似文献
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通过溶胶凝胶法制备了不同浓度的有机荧光分子BBOT(2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene);分散的纳米多孔二氧化硅凝胶薄膜,并获得了亮蓝色发光.本工作通过光谱技术研究了薄膜的发光特性;用扫描电子显微镜(SEM)技术表征了Btg)T/SiO2薄膜的表面形貌,分析了BBOT在二氧化硅凝胶中的表观分散行为和聚集态.通过研究有机荧光分子BBOT在介电常数从2到81的几种不同介质环境中的吸收和发射光谱的变化,揭示了BBOT在二氧化硅凝胶中吸收和发射主峰位相对于其在共溶剂1,4二氧六环中红移的原因是由于BBOT分子的电子基态比其激发态极性弱、与极性较大的二氧化硅凝胶相互作用的结果.薄膜发光强度随BBOT掺杂浓度的增加而增强,在6×10-3 M时达到最强.通过SEM技术表明,在掺杂浓度6×10-3M及以下薄膜没有相分离,仅在10-2 M时出现BBOT分子聚集形成的针状结晶形貌.本研究表明杂化薄膜通过纳米多孔二氧化硅的"笼"的作用获得BBOT有机分子在二氧化硅凝胶中的高度分散而抑制其浓度猝灭,得到高强度蓝色发光. 相似文献
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紫外光能量辅助CVD的反应机制 总被引:1,自引:0,他引:1
以二氧化硅,氮化硅薄膜为例论述了紫外光能量辅助化学汽相淀积的反应机制。二氧化硅薄膜的组成为纯SiO2;氮化硅薄膜中含有氧元素,组成氮氧化硅。 相似文献
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采用亚阈值激光能量对光学元件进行激光预处理后,其损伤阈值可以提高两三倍。在激光预处理过程中,不可避免地会使光学元件产生损伤,若产生的损伤不影响光学元件的使用性能,则原则上可以接受。首先介绍了HfO2/SiO2多层高反膜S-on-1损伤阈值测试方法,实验研究了激光预处理过程中光学薄膜元件的损伤过程,分析了预处理过程中薄膜损伤形貌对其光学性能及抗激光损伤阈值的影响。结果表明,对膜系为G/(HL)11H2L/A的HfO2/SiO2多层高反膜进行激光预处理,最外层SiO2层的破坏不影响薄膜整个反射率曲线。相反,由于消除了HfO2层的节瘤缺陷,薄膜的损伤阈值得到大幅度的提高。 相似文献
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In previous work the diffusion rate of water vapor through the polymer coating on optical fiber was estimated by monitoring the strength as a function of time after suddenly changing the ambient humidity. This technique is used here to measure the diffusion of moisture both into and out of two novel fiber coatings. The first specimen is a dual-coated fiber with silica particles added to its secondary coating. It is shown that the improvement in this fiber's reliability is not due to the silica particles adsorbing/absorbing the moisture. The second fiber, coated with a fluorinated polymer, was designed to have higher fatigue resistance as a result of having a lower permeability to moisture. It is found that even though this fiber had higher than normal resistance to fatigue, the diffusion of moisture through this coating was not substantially different than through typical coatings used on fibers for telecommunications applications. 相似文献
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Transparent and Robust Silica Coatings with Dual Range Porosity for Enzyme‐Based Optical Biosensing 下载免费PDF全文
Oswaldo Pérez‐Anguiano Raphaël Pugin Emmanuel Scolan Heinrich Hofmann 《Advanced functional materials》2017,27(16)
Hierarchically porous transparent silica coatings combine large specific surface area with enhanced pore accessibility for optical biosensing. This paper describes a versatile approach to fabricate optically transparent silica coatings with multiscale porosity. Thin films (around 1 μm in thickness) of an aqueous suspension of primary silica aggregates form a mesoporous, interconnected matrix, and sacrificial polymer particles template well‐defined, discrete macropores with high structural integrity. The total surface area achieved is around 200 m2 g?1 with mesopore sizes of 20–40 nm and macropores of 250 nm, with a total porosity of 84%. The macro/meso dual range of porosity allows enhanced biocatalyst loadings of l ‐lactate dehydrogenase for detection of lactate. The functionalized films showed a linear response within the range of interest of 1–20 × 10?3m of lactate. These biosensing coatings therefore strongly enhance sensitivity, speed and reliability of optically based lactate detection as compared to classical thin films with monomodal mesopore structure. Particle‐based simulations and experiments reveal that both the location and connectivity of the macropores control the biosensing performance. The coatings and procedure presented here are versatile, scalable, inexpensive, and are therefore compatible with a wide range of deposition techniques suitable for industrial and health care applications. 相似文献
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《Optical Fiber Technology》2007,13(1):27-31
Optical fibers require protection against moisture and oxygen, as well as mechanical and thermal protection. Although the reliability of polymer coatings has improved considerably over the last decade, it is still insufficient for particular applications. The authors recommend a newly invented nanoparticle material (NPM)-based fiber structures as a solution to an effective coating system. NPM is able to actively replace water molecules at the surface of the underlying material. The NPM fills in the existing or incipient flaws (cracks, etc.), thereby “healing” the damaged (defected) material. Nonpolymer coatings make the fiber mechanically reliable and environmentally durable. This is due to the “self-healing” ability of the thixotropic NPM compound, as well as to the NPM ability to “heal the wounds” on the surface of the silica material under stress. The objective of the two experiments undertaken and addressed in this study is to compare the mechanical and the environmental characteristics of NPM-based and “conventional” fibers under different loading and ambient conditions. We show that the NPM effectively protects the silica surface against damage that could be caused by water vapor. The NPM is promising as an effective coating that is able to improve dramatically the optical performance, mechanical reliability, environmental durability, and cost effectiveness of silica-based light-guides. 相似文献
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低损耗激光薄膜反射镜是环形激光器谐振腔的关键元件之一,首先设计和制备了工作角度为45的低损耗高反膜。为了提高低损耗高反膜的光学性能,采用高温热处理的方式,研究了热处理对低损耗高反膜的透射率、散射系数、表面粗糙度、相移等特性的影响。高温热处理对高反膜的散射系数、表面粗糙度影响较小,随着热处理温度的增加,高反膜相移逐渐降低。当退火温度为550 ℃时,环形激光器输出性能稳定性最好,当工作230 h 后,输出能量仅下降到初始值的90.5%。实验结果表明,采用合适的热处理方式,可以有效改善低损耗高反膜特性以及环形激光器的输出性能。 相似文献
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Shiqi Xiao Jiawei Wei Shue Jin Xue Xia Li Yuan Qin Zou Yi Zuo Jidong Li Yubao Li 《Advanced functional materials》2023,33(4):2208968
Building of multifunctional coatings in a more effective way is crucial for meeting the multilevel requirements of regenerative medicine. Herein, inspired by diatom and mussel, a specific but universal approach is proposed for building multifunctional coatings on slow-degradable and fast-degradable scaffolds or various substrates by using epigallocatechin gallate (EGCG) and polyethyleneimine (PEI) as bridges of silicon coupling. The results reveal that the polyphenol EGCG facilitates silica precipitation and coating topological morphology in synergy with PEI, and realizes antioxidant and immunomodulatory effects. The introduction of EGCG and the release of silicon ions present effective modulation of the immune microenvironment and remarkable promotion of angiogenesis and osteogenesis. The EGCG/silica coating strategy demonstrates a promising perspective for designing multifunctional coatings and optimizing tissue regeneration and reconstruction. 相似文献
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A new concept is proposed to synthesize mesoporous magnetic nanocomposite particles of great scientific and technological importance. Mesoporous silica coatings were created on micrometer‐sized magnetite (Fe3O4) particles using cetyltrimethylammonium chloride micelles as molecular templates. The characterization by transmission electron microscopy (TEM), nitrogen adsorption–desorption, diffuse‐reflectance Fourier‐transform infrared spectroscopy, and zeta‐potential measurements confirmed the deposition of mesoporous silica thin layers on the magnetite particles. The synthesized particles showed a drastic increase in specific surface area with an average pore size of 2.5 nm. The coating material showed a negligible effect on the saturation magnetization of the original particles that were fully protected by silica coatings. The synthesized mesoporous magnetic nanocomposite particles have a wide range of applications in toxin removal, waste remediation, catalysis, reactive sorbents, and biological cell separations. 相似文献
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ZHONGDi-sheng ZHANGYi-hong 《半导体光子学与技术》2001,7(1):30-41
Window coating used for the building in recent years is described.Important design principles, practical coating materials, and attainable optical properties for research-type coatings are introduced.Discussion is carried out on the spectrally selective coatings, the electrochromic coatings, and the thermochromic coatings. 相似文献
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光学薄膜的高重频激光损伤特性一直是激光薄膜研究者的重点。为了分析光学薄膜在高重频激光辐照下的损伤特性,探究其损伤机理,文中从实验出发,研究了重复频率10 kHz DPL 激光对光学薄膜元件的损伤特性。结果表明,修正膜层内的驻波场分布,降低膜层内高折射材料中的驻波场峰值可以提高高重频激光损伤阈值;从激光损伤形貌与辐照激光功率的关系上看,在高重频激光辐照下光学薄膜元件的损伤实质上是热效应和场效应共同作用下产生的微损伤累积放大所造成的。当薄膜吸收率较小时,损伤主要表现为场效应所致的微损伤累积放大,当薄膜吸收率较大时,损伤主要表现为热效应所致的微损伤累积放大。 相似文献