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961.
Bismuth borate glasses containing phosphors and luminescent rare-earths are of interest for applications in light-emitting devices. Herein, the influence of CuO impurities on red-emitting Eu3+-doped bismuth borate glasses of the 25Bi2O3-15BaO-10Li2O-50B2O3 type was investigated by various spectroscopic methods. The glasses were prepared by the melt-quench technique and characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, UV/Vis optical absorption (OA), and photoluminescence (PL) spectroscopy including decay kinetics assessment. The XRD data confirmed the amorphous nature of the glasses whereas FT-IR spectra indicated the basic structural features of trigonal BO3 units and BO4 tetrahedra. The OA analysis showed that addition of CuO up to 0.5 mol% results in significant growth of the visible Cu2+ absorption band around 715 nm, with slight decrease in the optical band gap energies assessed through Tauc plots. A drastic PL quenching of Eu3+ ions emission was evidenced concurring with the detrimental effect of Cu2+. The assessment of the Eu3+ emission decay curves revealed significant lifetime decrease of the 5D0 emitting state with increasing CuO concentration. An analysis of quenching constants was finally performed comparing results from integrated PL data with the emission decay rates. It is argued that the bismuth borate glass system supports an effective Eu3+→Cu2+ energy transfer (more so than phosphates) in connection with a strong spectral overlap between Eu3+ emission and Cu2+ absorption. 相似文献
962.
本研究以亲油性的双面胶作为基底,利用滴涂二乙炔单体结合紫外光聚合来制备均匀的聚二乙炔(PDA)薄膜,通过荧光和颜色两种信号变化模式(即"双模光学检测")研究了PDA薄膜对VOC气体的响应性,发现制备的PDA薄膜在2 min内就可以实现明显的荧光和颜色变化,有效解决了目前PDA薄膜在VOC气体检测方面存在响应速度慢、薄膜均一性差等问题.此外,为解决单一PDA薄膜的交叉响应性问题,本研究制备了四种不同的基于双面胶基底的PDA薄膜,并将制备的4种PDA薄膜集成到一片PDMS薄膜基底上来构建柔性的传感阵列,利用阵列的颜色变化结合模式识别技术,实现了对8种VOC气体的快速、灵敏区分.进一步将制备的PDA薄膜阵列用于健康人、模拟糖尿病及肾病患者呼出气体中VOC标志物的辨别和分析研究,发现可以将三类人的呼出气体清晰地区分,说明了该阵列在呼气疾病诊断中的应用前景.与目前报道的PDA薄膜阵列相比,本研究中基于双面胶基底的PDA薄膜阵列具有气体响应速度快、灵敏性高、柔韧性好、制备工艺简单、成本低、易于大规模制备等优点,有望用于实VOC气体检测研究中. 相似文献
963.
《Arabian Journal of Chemistry》2020,13(1):649-670
In recent years, metals based antitumor complexes have played a vital role in chemotherapy. Therefore, in this study, some new imine Cr(III), VO(II) and Ni(II) complexes incorporating ESAP imine ligand (2-Ethoxy-6-((2-hydroxy-phenylimino)-methyl)-phenol were designed and synthesized. The investigated complexes were fully characterized by micro analysis, infrared, electronic spectra, thermal analysis (TGA), conductivity as well as magnetic susceptibility measurements. Moreover, the stability constants of the prepared complexes were determined spectrophotometrically. The results suggest that the titled ESAP imine ligand serves as tri-dentate moiety through deprotonated two phenolic oxygen and azomethene nitrogen atoms for coordination to Cr(III) in octahedral geometry, tetrahedral to Ni(II) and distorted square pyramidal to VO(II). The electronic structure and nonlinear optical parameters NLO of the newly synthesized complexes are investigated theoretically at the B3LYP/GEN level of theory. The studied complexes show promising optical properties. Indeed, the prepared compounds were evaluated for antimicrobial effect against some types of bacteria and fungi. The investigated complexes exhibit a stronger antimicrobial efficiency compared to its ligand. Moreover, the interaction of the complexes with CT-DNA was monitored using spectral studies, viscosity and gel electrophoreses measurements. Furthermore, the cytotoxic activity of the prepared imine complexes on human colon carcinoma cells, hepatic cellular carcinoma cells and breast carcinoma cells have shown promising results and enhancement of the anti-proliferative activity compared to its ligand. The molecular docking into TRK (PDB: 1t46) was done for the optimization of the investigated compounds as potential TRK inhibitors. 相似文献
964.
965.
P. R. Srikanth Sharma Peiguang Zhou Harry L. Frisch 《Journal of polymer science. Part A, Polymer chemistry》1996,34(6):1049-1058
We report the synthesis and characterization of interpenetrating polymer networks (IPNs) exhibiting nonlinear optical (NLO) properties. The network consists of aliphatic polycarbonate urethane (PCU) and poly(methyl methacrylate-co-N,N-disubstituted urea), with a nonlinear optical (NLO) chromophore incorporated into N,N-disubstituted urea. The full IPNs have only one Tg, as determined by differential scanning calorimetry (DSC), together with scanning electron microscopy (SEM) observations, suggest a single phase morphology. The thin films of IPNs are transparent and the unpoled samples produced second harmonic generation (SHG) signals at room temperature. This result indicates that the NLO chromophore is oriented noncentrosymmetrically during the IPN formation process and is tightly held between the permanent entanglements of the two component networks of the IPN. © 1996 John Wiley & Sons, Inc. 相似文献
966.
967.
Haiming Wang 《Advanced functional materials》1996,6(4):163-168
A geometrical optics approach is used to analyse the reflection of a divergent beam falling onto a concave or convex surface. The polarisation state of a ray in the incident beam depends on the position where the ray impinges upon the surface. The distribution of transmittance over the surface for different polarisation states is determined. An integration of the transmittance distribution determines the total reflection loss of a coupling lens used in a laser diode to single-mode fibre coupling system. 相似文献
968.
Third-order nonlinear optical susceptibility, χ(3) of symmetrically octa-substituted metal-free phthalocyanine thin films measured by the third-harmonic generation technique are reported. The metal-free phthalocyanine has been found to show a χ(3) (−3ω; ω,ω, ω) value as large as 7.73×10−12 esu at 1.80 μm. The figure of merit, χ(3)/α, was estimated to be 4.17×1017 esu cm at 1.05 μm and 6.97×1016 esu cm at 1.65 μm. Both linear and third-order optical properties of liquid-crystalline metal-free phthalocyanines are discussed 相似文献
969.
YUYING WU HIROAKI IKEDA HIROFUMI YOSHIDA SHIGENOBU SHINOHARA 《International Journal of Communication Systems》1996,9(1):5-11
This paper describes two types of bidirectional addressed audio signal transmission systems where the square-wave frequency modulation (SWFM) and intensity modulation (IM) are used to obtain the optical SWFM signals generated from LEDs at 850 nm. The first one is an addressed audio signal transmission network of tree structure. The sender and auxiliary receiver in the centre are connected to four terminals, each consisting of a receiver and an auxiliary sender, through pairs of optical fibres and an optical splitter used as an optical signal distributor. The second one is a new type of full-duplex one-to-one communication system. The sender and auxiliary receiver in one terminal are connected to the receiver and auxiliary sender in the other terminal through an optical fibre and a pair of directional couplers. Although LEDs in the second system deliver optical SWFM signals at the same wavelength of 850 nm at the same time, the communications are satisfactory because there is no interference from one LED to the other. In both the first and second experimental systems, the audio signal, address, and SWFM carrier occupy 10 Hz to 20 kHz, 65 kHz to 710 kHz, and 6 MHz, respectively. The SNR and distortion were 62 dB and 0.4 per cent, respectively. 相似文献
970.
Sutiyao Marturunkakul Jeng-I Chen Lian Li Jayant Kumar Sukant K. Tripathy 《先进技术聚合物》1996,7(4):303-308
There has been a tremendous recent interest in the development of second-order nonlinear optical (NLO) polymeric materials for photonic applications. However, a major drawback of second-order NLO polymers that prevents them from being used in device applications is the instability of their electric field induced dipolar alignment. The randomization of the dipole orientation leads to the decay of second-order optical nonlinearities. Numerous efforts have been made to increase the stability of the second-order NLO properties of polymers. The search for new approaches to develop NLO polymers with optimal properties has been an active research area since the past decade. A novel approach, combining the hybrid properties of high glass transition temperatures, extensively extensively crosslinked networks and permanent entanglements, based on interpenetrating polymer networks (IPN) is introduced to develop stable second-order NLO materials. Two types of IPN systems are prepared and their properties are investigated. The designing criteria and the rationale for the selection of polymers are discussed. The IPN samples show excellent temporal stability at elevated temperatures. Long-term stability of the optical nonlinearity at 100°C has been observed in these materials. Temporal stability of the NLO properties of these IPNs is synergistically enhanced. Relaxation behavior of the optical nonlinearity of an IPN system has been studied and compared with that of a typical guest/host system. The improved temporal stability of the second-order NLO properties of this IPN system is a result of the combination of the high rigidity of the polymer backbones, crosslinked matrices and permanent entanglements of the polymer networks. A slight modification of the chemical structure resulted in an improvement of the optical quality of the sample. 相似文献