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941.
NIE Ling-mei ZHA Tao XIA Bin-biao ZHANG Kai GUAN Zhi-qiang ZHAO You-quan YUAN Da CAO Xuan LIU Yan 《光谱学与光谱分析》2021,41(11):3486-3492
荧光猝灭法是快速测量污水、地表水以及渔业养殖水环境中溶解氧含量的先进技术之一,氧敏感膜是荧光猝灭法检测技术的核心,高荧光发射效率的氧敏感膜具有灵敏度高、特异性强、信噪比高的优点,检测结果更为准确。高效率是优选氧敏感膜的依据,也是溶解氧检测元器件、检测电路和检测光路优化设计的关键。现有溶解氧荧光检测装置中未有对氧敏感膜进行质量评估的标准方法,基于对已有传感器探头光路和电路的研究,该研究分析了全波段的荧光发射效率,选用大功率氙灯作为激发光源,基于连续单波长逐级扫描进行单色分光,构建了氧敏感膜的激发光-荧光光谱扫描装置,然后通过扫描测定氧敏感膜的激发光光谱和荧光光谱,提出并建立了荧光发射效率计算方法,提出的方法能客观地评估荧光发射能力,准确寻找最佳激发波长。为验证该方法的可行性,对来自国内外的多个氧敏感膜样品进行了实验测定,测试结果表明:单张氧敏感膜荧光发射效率随波长变化,呈多峰分布,同一型号的样品荧光效率曲线相似,但荧光发射效率差异较大,同一激发波长下荧光发射效率最大者较最小者高出14.5%,三张氧敏感膜的最大峰值波长均不同,分别为:401,543和435 nm,但发射峰值波长均为650 nm;不同型号的氧敏感膜相比较,最大荧光发射效率可相差1~2个数量级;实测传感器中使用的激发波长,其所选用的激发波长并非最大发射峰值波长,其荧光发射效率仅为最大荧光发射效率的1/2,表明传感器光源可以进一步优化选型。综上所述,本文建立了一种溶解氧敏感膜荧光发射效率检测系统,提出了以荧光发射效率评估氧敏感膜的方法,并开展了相关实验测定。本文工作可望用于新型氧敏感膜材料、工艺的研究及传感器优化设计与制造。 相似文献
942.
A facile, efficient and environment-friendly protocol for the synthesis of 4-hydroxy-6-methyl-3-(1-(phenylimino)ethyl)-2H-pyran-2-one derivatives has been developed by the convenient ultrasound-mediated condensation of amine with dehydroacetic acid. This method provides several advantages over current reaction methodologies including a simple work-up procedure, shorter reaction times and higher yields. 相似文献
943.
Qiming Liu Xuan He Xiujian Zhao Feng Ren Xiangheng Xiao Changzhong Jiang Xiong Zhou Liping Lu Hui Zhou Shixiong Qian B. Poumellec M. Lancry 《Journal of nanoparticle research》2011,13(9):3693-3697
Ag-nanoparticles were embedded in 56GeS2?C24Ga2S3?C20KBr chalcohalide glass with average size varying from 100 to 300 nm. A large femtosecond optical Kerr effect indicated an enhancement of third-order optical nonlinearity due to Ag-nanoparticles observed by AFM images. Among these Ag-nanoparticles-embedded chalcohalide glass samples, the sample (c) with the second largest implanting dose 1 × 1017 ions/cm2 showed the largest value of ??(3) 5.34 × 10?13 esu, which was ten times larger than that of the substrate. The nonlinear relation between the implanted dose and third-order optical nonlinearity is strongly related to the intrinsic local field and Ag-nanoparticles interaction in the glasses. 相似文献
944.
Transient chaos in optical metamaterials 总被引:1,自引:0,他引:1
We investigate the dynamics of light rays in two classes of optical metamaterial systems: (1) time-dependent system with a volcano-shaped, inhomogeneous and isotropic refractive-index distribution, subject to external electromagnetic perturbations and (2) time-independent system consisting of three overlapping or non-overlapping refractive-index distributions. Utilizing a mechanical-optical analogy and coordinate transformation, the wave-propagation problem governed by the Maxwell's equations can be modeled by a set of ordinary differential equations for light rays. We find that transient chaotic dynamics, hyperbolic or nonhyperbolic, are common in optical metamaterial systems. Due to the analogy between light-ray dynamics in metamaterials and the motion of light in matter as described by general relativity, our results reinforce the recent idea that chaos in gravitational systems can be observed and studied in laboratory experiments. 相似文献
945.
In this paper, we consider the value distribution of meromorphic solutions of order zero of some kind of q-difference equations and examples are also given to elaborate our results. 相似文献
946.
Improvement of the switching frequency of a liquid-crystal spatial light modulator with optimal cell gap 总被引:1,自引:0,他引:1
In the application of a nematic liquid-crystal (LC) spatial light modulator, we derived the formula of retardation dynamic response of the device by solving the Erickson-Leslie equation. Then, the response time of the 2π phase change can be expressed as a function of the LC cell gap. The theoretical and experimental results all indicate that the response time of 2π first decreases and then increases with the LC cell gap increasing, and there is an optimal cell gap to obtain the shortest response time. Therefore, the method of optimizing the cell gap shows potential to improve the switching frequency for all type of nematic LC optical device with specific modulation quantity. 相似文献
947.
Steenackers M Gigler AM Zhang N Deubel F Seifert M Hess LH Lim CH Loh KP Garrido JA Jordan R Stutzmann M Sharp ID 《Journal of the American Chemical Society》2011,133(27):10490-10498
A critical bottleneck for the widespread use of single layer graphene is the absence of a facile method of chemical modification which does not diminish the outstanding properties of the two-dimensional sp(2) network. Here, we report on the direct chemical modification of graphene by photopolymerization with styrene. We demonstrate that photopolymerization occurs at existing defect sites and that there is no detectable disruption of the basal plane conjugation of graphene. This method thus offers a route to define graphene functionality without degrading its electronic properties. Furthermore, we show that photopolymerization with styrene results in self-organized intercalative growth and delamination of few layer graphene. Under these reaction conditions, we find that a range of other vinyl monomers exhibits no reactivity with graphene. However, we demonstrate an alternative route by which the surface reactivity can be precisely tuned, and these monomers can be locally grafted via electron-beam-induced carbon deposition on the graphene surface. 相似文献
948.
In this study we present the effects of iron oxide (Fe2O3) on titanium dioxide (TiO2) in synthesising visible-light reactive photocatalysts. A Fe2O3-TiO2 composite photocatalyst was synthesized from Fe2(SO4)3 and Ti(SO4)2 by a ethanol-assisted hydrothermal method. The preparation conditions were optimized through the investigation of the effects of hydrothermal temperature and time as well as molar ratio of Ti to Fe on the photocatalytic activity. The visual, physical and chemical properties of the Fe2O3-TiO2 composites were investigated. The results showed that α-Fe2O3 and anatase TiO2 were present in the composites. The Fe2O3-TiO2 synthesized under optimum condition consisted of mesoporous structure with an average pore size of 4 nm and a surface area of 43 m2/g. Under visible and solar light irradiation, the photocatalytic activity of optimized sample was significantly higher than that of pure TiO2. This sample led to a photodegradation efficiency of 90% and 40% of auramine under visible light and solar light, respectively. 相似文献
949.
950.
The D(d,p)T reaction in Be metal environments has been measured to investigate the electron screening effect in metals in an energy region of from 5.5 keV to 10 keV in a center of mass system (CMS) at a temperature of 121 K. The depth distribution of deuteron density in Be metals has an impact on the observed reaction yields. A model of deuteron density distribution in metal has been proposed to obtain the original yields. A screening energy of (116±46) eV has been obtained with the assumed deuteron density distribution model. 相似文献