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31.
32.
以丙醇锆(ZrPr)为锆源,二乙醇胺(DEA)为络合剂,原位引入聚乙烯吡咯烷酮(PVP),在乙醇体系中成功地合成了PVP掺杂-ZrO2溶胶.采用旋涂法在K9玻璃基片上制备了PVP-ZrO2单层杂化薄膜.用不同掺杂量的PVP-ZrO2高折射率膜层与相同的SiO2低折射率膜层交替沉积四分之一波堆高反射膜.借助小角X射线散射研究胶体微结构,用红外光谱、原子力显微镜、紫外/可见/近红外透射光谱、椭圆偏振仪以及1064nm的强激光辐照实验对薄膜的结构、光学和抗激光损伤性能进行表征.研究发现,体系组成的适当配置可以在溶胶稳定的前提下实现ZrPr的充分水解,赋予薄膜良好的结构、光学和抗激光损伤性能.杂化体系中,DEA与ZrPr之间强的配合作用大大降低了ZrO2颗粒表面羟基的活性,使得PVP大分子只是以微弱的氢键与颗粒的表面羟基作用而均匀分散于ZrO2颗粒的周围,对颗粒的形成和生长无显著影响.因而在实验研究范围内,随PVP含量的增大,PVP-ZrO2杂化膜层的折射率和激光损伤阈值均无显著变化.但是,薄膜中均匀分布的PVP柔性链可以有效促进膜层应力松弛,显著削弱不同膜层之间的应力不匹配程度、大大方便多层光学薄膜的制备.当高折射率膜层中PVP的质量分数达到15%-20%时,膜层之间良好的应力匹配使得多层高反射膜的沉积周期数可达到10以上.沉积1O个周期的多层反射膜,在中心波长1064nm处透射率约为1.6%-2.1%,接近全反射特征,其激光损伤阈值为16.4-18.2J/cm2(脉冲宽度为1ns). 相似文献
33.
Da-ping Wan Hong-bin Liu Yu-ming Wang De-jin Hu Zhen-xing Gui 《Optics & Laser Technology》2008,40(2):309-314
Laser texturing is a novel technique that may be used to texture a cold roller in the process of manufacturing high quality steel sheets. With the aim of improving the quality of the textured roller by using a CO2 laser, a new laser beam modulating device is proposed. An optical beam expander with a fast rotating chopper system is designed. The laser pulse is split into two parts by the chopper blades; one is the preheating pulse that is reflected onto optical loop mirrors; the other is the directly transmitted pulse that creates the craters at the preheated spots. The preheating beam focus spot size and position can be adjusted. The focusing characteristics and optical parameter compensation for the flying optics are investigated. The heat transfer and melt process of laser texturing are numerically simulated. The effects of the double pulses on the texturing are analyzed. The effect of preheating the sample ahead of the laser texturing pulse is examined. The surface profile and bump hardness show improvements by using this approach. 相似文献
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Dr. Ming-Hui Sun Prof. Dr. Li-Hua Chen Shen Yu Prof. Dr. Yu Li Xian-Gang Zhou Dr. Zhi-Yi Hu Prof. Dr. Yu-Han Sun Prof. Dr. Yan Xu Prof. Dr. Bao-Lian Su 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(44):19750-19759
Zeolite Beta single crystals with intracrystalline hierarchical porosity at macro-, meso-, and micro-length scales can effectively overcome the diffusion limitations in the conversion of bulky molecules. However, the construction of large zeolite Beta single crystals with such porosity is a challenge. We report herein the synthesis of hierarchically ordered macro-mesoporous single-crystalline zeolite Beta (OMMS-Beta) with a rare micron-scale crystal size by an in situ bottom-up confined zeolite crystallization strategy. The fully interconnected intracrystalline macro-meso-microporous hierarchy and the micron-sized single-crystalline nature of OMMS-Beta lead to improved accessibility to active sites and outstanding (hydro)thermal stability. Higher catalytic performances in gas-phase and liquid-phase acid-catalyzed reactions involving bulky molecules are obtained compared to commercial Beta and nanosized Beta zeolites. The strategy has been extended to the synthesis of other zeolitic materials, including ZSM-5, TS-1, and SAPO-34. 相似文献
36.
Zhong Ju Liu Wenwen Shi Gui Mei Shi Wei Jiang 《International Journal of Theoretical Physics》2018,57(1):184-194
An array of coupled cavities, each of which contains a triangle-down-level atom, is investigated. An effective Hamiltonian can be achieved under the strong classical driving. We can control the transition between Mott-insulator and superfluid states by the classical driving. The frequency conversion in one site has the same effects of nonlinear in BH hamiltonian which can induce insulator-superfluid states. 相似文献
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Chunxu Bai Ke-Wei Wei Gui Yang Yanling Yang 《Applied Physics A: Materials Science & Processing》2013,111(2):619-628
Transport characteristics of relativistic electrons through graphene-based d-wave superconducting double barrier junction and ferromagnet/d-wave superconductor/normal metal double junction have been investigated based on the Dirac–Bogoliubov–de Gennes equation. We have first presented the results of superconducting double barrier junction. In the subgap regime, both the crossed Andreev and nonlocal tunneling conductance all oscillate with the bias voltage due to the formation of Andreev bound states in the normal metal region. Moreover, the critical voltage beyond which the crossed Andreev conductance becomes to zero decreases with increasing value of superconducting pair potential α. In the presence of the ferromagnetism, the MR through graphene-based ferromagnet/ d-wave superconductor/normal metal double junction has been investigated. It is shown that the MR increases from exchange splitting h 0=0 to h 0=E F (Fermi energy), and then it goes down. At h 0=E F, MR reaches its maximum 100. In contrast to the case of a single superconducting barrier, Andreev bound states also manifest itself in the zero bias MR, which result in a series of peaks except the maximum one at h 0=E F. Besides, the resonance peak of the MR can appear at certain bias voltage and structure parameter. Those phenomena mean that the coherent transmission can be tuned by superconducting pair potential, structure parameter, and external bias voltage, which benefits the spin-polarized electron device based on the graphene materials. 相似文献
39.
We investigate the multipartite entanglement in arbitrary dimensional systems, and separability criteria for nonseparability in n-partite quantum states are derived. Examples such as the generalized noisy-W state and the GHZ basis states mixed with white noise are provided to show that our criteria are independent of and stronger than previously reported ones. Our criteria can also be expressed by the elements of the density matrix, which allows a simple and practical evaluation and computation. The experimental implementation of our criteria is also discussed. 相似文献
40.