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Synthesis of yttrium doped BiOF/RGO composite for visible light: Photocatalytic applications
摘要： In this present work, yttrium doped bismuth oxy fluoride/reduced graphene oxide (Y-BiOF/RGO) composite was synthesized using a simple solvothermal method. As synthesized composite was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) techniques. The photocatalytic property was evaluated towards the degradation of methylene blue (MB) dye under the visible-light irradiation. The characterization results highlighted that the efficient incorporation of both yttrium ions and RGO greatly reduced the recombination rate of BiOF and extended the visible-light absorption ability. As synergistic effects, the prepared Y-BiOF/RGO composite exhibited maximum degradation rate of 98% in 360 min, which is 6.5 times higher than pure BiOF. The clear mechanism for the enhanced photo-activity by Y-BiOF/RGO was discussed.
关键词： Semiconductors,BiOF,Photocatalysts,Yttrium,Graphene,Visible light
更新于2025-09-04 15:30:14
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[IEEE 2017 IEEE Workshop on Recent Advances in Photonics (WRAP) - Hyderabad (2017.12.18-2017.12.19)] 2017 IEEE Workshop on Recent Advances in Photonics (WRAP) - Effect of Moth-Eye Antireflective Coatings in Extraction of Far Field Intensity of an Organic Light Emitting Diode (OLED)
摘要： In this work, the OLED is modelled using Moth-eye Anti Reflective coatings to extract maximum far field intensity compared to Conventional OLED. Finite difference time domain method is used to simulate the OLED structure. The presented structure shows maximum far field intensity of 3.6μV/m.
关键词： Moth eye Antireflectors,Organic Light Emitting Diode,Total Internal Reflection
更新于2025-09-04 15:30:14
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI, USA (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - A Quantitative Model for Estimating the Scale of Photochemically Induced Ischemic Stroke
摘要： Photothrombosis is a technique that can induce ischemic cortical infarcts using the photodynamic effect of anionic xanthene dyes, typically Rose Bengal, to cause occlusion of cerebral blood circulation. The ability to quantitatively predict the scale of the lesion in photothrombotic procedures can offer crucial insight in the development and implementation of light-induced stroke models in animals. In this article, we introduced a quantitative model that could estimate the normalized light intensity distribution in tissue which scatters photons from a collimated beam. We simulated the penetration and scattering profile of light of Rose Bengal’s characteristic absorption wavelengths in mouse cortex. We further illustrated that our model could estimate the spatial extent of effective region under photothrombotic protocols, and how this model can be used to titrate the intensity and geometry of light beams used to generate infarcts of desired dimensional characteristics.
关键词： Rose Bengal,ischemic stroke,Photothrombosis,quantitative model,light scattering
更新于2025-09-04 15:30:14
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Role of Multiphoton Ionization in the Short-Wavelength Broadening of the Spectrum of a Light Bullet in the Middle Infrared Range
摘要： The short-wavelength cutoff of the anti-Stokes wing of the supercontinuum in the spectrum of a light bullet at filamentation of femtosecond radiation at a wavelength tunable in a wide range of the middle infrared range in fused silica and fluorides has been studied for the first time. A physical model for the formation of the spectrum of the light bullet has been proposed on the basis of the spectral broadening caused by the phase self-modulation of the light field on the trailing edge of the light bullet at the generation of a plasma in the process of multiphoton ionization. Within this model, a function has been obtained to determine the wavelength shift of the short-wavelength cutoff as a function of the multiphoton order. This function is in agreement with experimental results.
关键词： supercontinuum,light bullet,spectral broadening,multiphoton ionization,middle infrared range
更新于2025-09-04 15:30:14
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Synthesis of Lead-Doped SrTiO <sub/>3</sub> Perovskite Type Oxides and Their Photocatalytic Activity Under Visible Light Irradiation
摘要： Pure and lead-doped SrTiO3 perovskite type oxides were successfully synthesized by sol–gel method and characterized by XRD, SEM and DRS. From the results of XRD, the metal replacement with the Pb ion on the crystal lattice does not change the high crystallinity of the perovskite structure. UV-vis DRS analysis shows that Pb was in situ doped in the lattice of SrTiO3 and the absorption band shifted to a higher wavelength on the Pb-doped SrTiO3 sample compared to the pure SrTiO3 sample. We also investigated the photocatalytic activity of Pb-doped SrTiO3 for the decomposition of Rhodamine B under visible light irradiation. From the results of photocatalytic decomposition of RhB, a doping of lead into SrTiO3 perovskite oxides enhanced the photocatalytic activity under visible light irradiation.
关键词： Photocatalytic Activity,Visible Light Irradiation,Lead-Doped SrTiO3
更新于2025-09-04 15:30:14
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Chaos Synchronization in Visible Light Communications with Variable Delays Induced by Multipath Fading
摘要： Visible Light Communication (VLC) uses light-emitting diodes to provide wireless connectivity in public environments. Transmission security in this emerging channel is not trivial. Chaotic modulation techniques can provide encryption directly in the physical layer based on the random-alike evolution and strong synchronization prospect given by deterministic chaos. In secure chaotic inclusion or embedding methods, continuous-time chaos oscillator models need to be synchronized via a coupling carrier. Here we present a ?rst numerical simulation study for the impact of the variable delays induced by line-of-sight and non-line-of-sight multipath fading in complete chaotic synchronization. More precisely, we analyze a chaotic Colpitts oscillator that is simultaneously transmitting the carrier to several mobile receivers via nine spotlights. Such induced delays depend on both the receiver position and the carrier frequency, in?uencing the complete synchronization required in modulation via chaotic inclusion. Correlation values for several receiver positions and carrier frequencies are presented, examining the progressive emergence of the multipath effect and its impact on chaotic synchronization. We show that, for the chaotic oscillator and coupling applied in the de?ned room settings, complete chaotic synchronization can be achieved and that it is robust up to the tens of MHz region.
关键词： multipath channels,network security,chaotic communication,visible light communication,nonlinear systems,chaos synchronization
更新于2025-09-04 15:30:14
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Applicability of Effective Medium Approximations to Modelling of Mesocrystal Optical Properties
摘要： Rigorous superposition T-matrix method is used to compute light interaction with mesocrystalline structures. The results are used to validate the applicability of effective medium theories for computing the effective optical constants of mesocrystal structures composed of optically isotropic materials. It is demonstrated that the Maxwell-Garnett theory can fit the rigorous simulation results with an average accuracy of 2%. The thus obtained refractive indexes can be used with any electromagnetic simulation software to represent the response of mesocrystals composed of optically small primary particles arranged into a cubic type lattice structures.
关键词： Mie scattering,numerical modelling,particles,mesocrystals,T-matrix,Maxwell-Garnett,light scattering,effective medium theory
更新于2025-09-04 15:30:14
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Cancellation of Bessel beam side lobes for high-contrast light sheet microscopy
摘要： An ideal illumination for light sheet fluorescence microscopy entails both a localized and a propagation invariant optical field. Bessel beams and Airy beams satisfy these conditions, but their non-diffracting feature comes at the cost of the presence of high-energy side lobes that notably degrade the imaging contrast and induce photobleaching. Here, we demonstrate the use of a light droplet illumination whose side lobes are suppressed by interfering Bessel beams of specific k-vectors. Our droplet illumination readily achieves more than 50% extinction of the light distributed across the Bessel side lobes, providing a more efficient energy localization without loss in transverse resolution. In a standard light sheet fluorescence microscope, we demonstrate a two-fold contrast enhancement imaging micron-scale fluorescent beads. Results pave the way to new opportunities for rapid and deep in vivo observations of large-scale biological systems.
关键词： light sheet microscopy,Bessel beams,fluorescence imaging,droplet illumination,Airy beams
更新于2025-09-04 15:30:14
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Light energy accumulation by cholesteric liquid crystal layer at oblique incidence
摘要： Oblique propagation of light through a planar layer of a cholesteric liquid crystal (CLC) is solved by Ambartsumian’s modified layer addition method. Two cases are considered, namely, the case when dielectric boundaries have a minimum influence on light transmission and the case when the CLC layer is in a vacuum. It is shown that in the first case a total internal reflection can happen for the fast eigen-mode at large incidence angles. New important features of light reflection (transmission) spectra, photonic density of states and accumulated energy density in the CLC layer are studied. The light localisation peculiarities in the CLC layer at oblique incidence is investigated too. It is shown that the light localisation for both the long-wavelength edge mode and the short-wavelength edge mode changes differently when the incidence angle changes. The obtained results can be used in the design of low-threshold lasers, in solar cell systems, in chiral photonics, in systems strongly absorbing light at certain wavelengths and when designing systems with absorption suppression created on the base of absorbing media, etc.
关键词： total internal reflection,Cholesteric liquid crystals,photonic band gap,light localisation
更新于2025-09-04 15:30:14
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Office light control moving toward automation and humanization: a literature review
摘要： This review was designed to survey the development of control technology and strategies for office light environment from 1993 to 2017 by documentary research. Search engines were applied and 100 publications were selected and analyzed with the focus on energy saving and visual comfort as well as related areas, such as control technology and strategies, shading, light sources and simulation tools. It was found that general tendency in office light control technology and strategies moves towards creating more occupant-friendly and less energy consumption convergence and remarkable progress has been made in computer- and network-based integrated light control technology. Therefore, it could be predicted that in the next decade artificial intelligence and network-based office light control technology will be further developed into a complete automatic control system. Moreover, it is likely that, with the further exploration of Big Data, light control system could be merged with other control systems in an office building, such as heating, cooling, humidity, and ventilation system, forming self-learning and self-evolution control system.
关键词： visual comfort,office light environment,simulation tools,Lighting control,energy-saving
更新于2025-09-04 15:30:14