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51.
A series of Zr:Fe:LiNbO3 crystals with various levels of ZrO2 doping were grown by Czochraski technique. The optical damage resistance and photorefractive properties were deeply explored. The results showed that the ability optical damage resistance increased remarkably when the concentration of ZrO2 is over threshold concentration, but which is lower than that of traditional damage resistant additive MgO. While, the holographic storage properties can be greatly enhanced by proper level of ZrO2 doping in Fe:LiNbO3. In terms of ions' site occupation model, the photo-damage resistant ability enhancement and the change of the photorefractive properties were discussed. 相似文献
52.
Ultracompact and dynamically tunable plasmonic THz switch based on graphene microcavity metamaterial
Optical Review - We propose and discuss a compact and tunable plasmonic terahertz (THz) metamaterial switch based on graphene microcavity. Due to the joint effect of graphene plasmon resonances and... 相似文献
53.
Yuzhen Zhao Shaopeng Tian Zhendong Wang Min Zhu Huaping Ren Qiang Ma 《Molecular Crystals and Liquid Crystals》2017,656(1):113-123
Nowadays, with the increasing use of high-power laser, research and development of laser-damage prevention materials with multifunctional features and wideband wavelengths are urgent and indispensable. In the paper, cholestric liquid crystal (ChLC) is first proposed to be doped with a high-efficiency optical limiting material, 6, 6-phenyl C61-butyric acid methyl ester (PCBM), to fabricate a new-type laser-damage-prevention film. The ChLCs have the desired reflection wavelengths covering 750–2300 nm, which is an effective and potential candidate for the prevention of continuous or tuneable laser in near infrared (NIR) region. Meanwhile, the solubility of PCBM in LC and its nonlinear absorption property of are discussed, and it was proved that the good solubility of PCBM in LC contributed to the excellent nonlinear absorption of mixture (LC doped with PCBM). Taking advantages of this phenomenon, a novel composite film of ChLCs doped with PCBM is prepared by UV polymerization. As a result, the composite film not only performs broadband reflection in NIR region, but also exhibits a strong nonlinear absorption and excellent optical limiter properties in visible region, which proves the film's potential application in laser damage prevention. 相似文献
54.
55.
Two benzoxazinone compounds as epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors were synthesized and characterized by NMR and high-resolution mass spectrometry (HRMS). An efficient chlorination method was introduced in the synthesis of 4-chloro-2-oxo-2H-benzoxazinone-6-yl acetate. The inhibition activities of the target compounds and the important intermediates for EGFR tyrosine kinase activity in vitro were determined. 相似文献
56.
A series of Hf:Fe:Mn:LiNbO3 crystals with various levels of HfO2 doping were grown by Czochralski technique. The infrared spectra and ultraviolet spectra were measured and discussed to investigate their structure and defects. The optical damage resistance was characterized by the transmitted beam pattern distortion method. The nonvolatile two-color holographic recording experimental results showed that the recording speed was faster with the increase of HfO2 doping concentration and at the same time little loss of nonvolatile diffraction efficiencies could be achieved. 相似文献
57.
Application of an improved subpixel registration algorithm on digital speckle correlation measurement 总被引:2,自引:0,他引:2
Digital speckle correlation method (DSCM) has been widely used in experimental mechanics to obtain the surface deformation fields. One of the challenges in practical applications is how to obtain the high accuracy with far less computation complexity. To determine the subpixel registration of the DSCM, a high efficient gradient-based algorithm is developed in this paper. The principle is described and four different modes of the algorithm are given. Based on computer-simulated images, the optimal mode of the algorithm is verified through the comparison of computation time, optimal subset-region size and sensitivity of the four modes. The influences of speckle-granule size and speckle-granule density on accuracy are studied and a quantitative estimation of the optimal speckle-granule size range is obtained. As the applications of this method, the practical deformation measurements with the rigid body translation and rotation as well as an experiment on biomechanics are presented to certify the feasibility and the validity of the algorithm. 相似文献
58.
YANG Shaopeng FU Guangsheng LI Xiaowei & TIAN Xiaodong College of Physics Science Technology Hebei University Baoding China 《中国科学G辑(英文版)》2004,47(6)
Chemical sensitization is a widely adopted technique that improves the photo-graphic sensitivity of silver halide crystals with basic emulsion. Sensitization centers,which can save photoelectrons in the process of latent-image formation, have beenformed on microcrystals after chemical sensitization. Therefore, chemical sensitizationwas widely adopted for many years. Sulfur sensitization is an important chemical sen-sitization technique in all chemical sensitization methods. First, in 1925, Sh… 相似文献
59.
Modeling the multistep flow of energy in light-harvesting dendrimers presents a considerable challenge. Recent studies have introduced an operator approach based on a matrix representation of the connectivity between constituent chromophores. Following a review of the theory, detailed applications are now shown to exhibit the time development of the core excitation following pulsed laser irradiation and the steady-state behavior that can be expected under conditions of constant illumination. It is also shown how energy capture by whole dendrimers can be analytically related to chromophore pair-transfer properties and, in particular, the spectroscopic gradient toward the core. Indicative calculations also illustrate the consequences of tertiary folding. In each respect, the model affords opportunities to derive new, physically meaningful information on the photophysical and structural features of dendrimeric systems. 相似文献
60.
The measurement of local oxygen level in 3D cell culture is desired but remains as a challenge problem. We developed a 3D cell scaffold with luminescence-based oxygen sensing capability that opens the possibility of 3D mapping of oxygen level during cell growth. Hydrogel inverted opal scaffold was prepared by photo-polymerization of poly(2-hydroxyethyl methacrylate (pHEMA) and poly(methacryloyloxy)ethyl-trimethylammonium chloride (pMEATAC) monomer using close-packed bead assembly as template. Tris(4,7-diphenyl-1,10-phenanthroline)ruthenium chloride (Ru(dpp)(3)), was coated on the pHEMA-pMEATAC 3D scaffolds by layer-by-layer (LBL) assembly. pHEMA-pMEATAC copolymer was coated on top of the Ru(dpp)(3) layer as a protection layer. The fluorescence emission of Ru(dpp)(3) can be dynamically quenched by oxygen. By measuring the emission intensity of the scaffold, the local oxygen level can be monitored. The hydrogel scaffolds are transparent, and thus 3D fluorescence intensity can be mapped by confocal microscopy. Human bone marrow stromal cells HS-5 were successfully cultured on the oxygen sensing scaffold, and the observed Ru(dpp)(3) emission intensity from the scaffold was stronger in cell rich area, which indicates a lower oxygen level due to the consumption of the cells. 相似文献