- 标题
- 摘要
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- 实验方案
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Pattern of Retinal Nerve Fiber Layer Thickness Loss in Fetal Alcohol Syndrome: A Spectral-Domain Optical Coherence Tomography Analysis
摘要： Introduction: Optic disc hypoplasia is a common feature in fetal alcohol syndrome. Thus, we aimed to evaluate the optic disc morphology changes and the peripapillary retinal nerve fiber layer thickness in these patients. Material and Methods: We performed spectral-domain optical coherence tomography in a cohort of 11 patients (22 eyes) with fetal alcohol syndrome and in an age-matched control group. We evaluated optic nerve head parameters (optic disc area and diameter, rim area, cup/disc horizontal and vertical ratios) and peripapillary retinal nerve fiber layer thickness. Results: Mean optic disc area, rim area and optic disc diameter were, respectively, in fetal alcohol syndrome patients and control subjects: 1.540 ± 0.268 and 1.748 ± 0.326 mm2; 1.205 ± 0.286 and 1.461 ± 0.314 mm2; 1.417 ± 0.124 and 1.501 ± 0.148 mm (p < 0.05). We found no significant differences between groups for cup/disc ratios. Mean retinal nerve fiber layer thickness was significantly lower in fetal alcohol syndrome patients (90.500 ± 9.344 μm) as compared to controls (111.000 ± 7.855 μm) (p < 0.0001). Analysis showed a significant decrease in retinal nerve fiber layer thickness for the superior, inferior and nasal quadrants (p < 0.005). The temporal quadrant showed no significant differences. Discussion: Optic disc area, rim area and optic disc diameters were significantly reduced in fetal alcohol syndrome patients. Although mean peripapillary retinal nerve fiber layer thickness was decreased, the temporal quadrant was spared. Conclusion: In addition to a smaller optic disc area/ diameter and rim area, we found a heterogeneous peripapillary retinal nerve fiber layer thickness loss in fetal alcohol syndrome patients with sparing of the temporal quadrant. Spectral-domain optical coherence tomography may be useful to determine the presence of fetal alcohol syndrome status.
关键词： Retina,Fetal Alcohol Spectrum Disorders,Optic Nerve Diseases,Nerve Fibers
更新于2025-09-23 15:23:52
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Controlling the emission and absorption spectrum of a quantum emitter in a dynamic environment
摘要： We study the emission spectrum and absorption spectrum of a quantum emitter when it is driven by various pulse sequences. We consider the Uhrig sequence of nonequidistant πx pulses, the periodic sequence of πxπy pulses and the periodic sequence of πz pulses (phase kicks). We find that, similar to the periodic sequence of πx pulses, the Uhrig sequence of πx pulses has emission and absorption that are, with small variations, analogous to those of the resonance fluorescence spectrum. In addition, while the periodic sequence of πz pulses produces a spectrum that is dependent on the detuning between the emitter and the pulse carrier frequency, the Uhrig sequence of nonequidistant πx pulses and the periodic sequence of πxπy pulses have spectra with little dependence on the detuning as long as it stays moderate along with the number of pulses. This implies that they can also, similar to the previously studied periodic sequence of πx pulses, be used to tune the emission or absorption of quantum emitters to specific frequencies, to mitigate inhomogeneous broadening and to enhance the production of indistinguishable photons from emitters in the solid state.
关键词： spectral diffusion,emission/absorption spectrum,solid state emitter,pulse-driven emitter
更新于2025-09-23 15:23:52
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Tuning the Spectrum Properties of Fullerene C60: Using a Strong External Electric Field
摘要： The electric ?eld can change the absorption of fullerene C60 to different wavelengths of light by affecting the vibrational modes and electronic transitions. The IR spectrum of fullerene C60 under the strong electric ?eld is studied on B3LYP/6-31G* basis set using density function theory. With the external electric ?eld decreasing, silent modes Hg(1), Ag(1), Gu(2), Hg(5), Ag(2), Hu(7) become active. Meanwhile, UV–Vis spectrum, the excitation energy, excitation wavelength and oscillator strength of ?rst fourteen excited states of fullerene C60 under the ?eld are also studied in B3LYP/6-31G* basis set using time-dependent density functional theory. With the electric ?eld increasing, the absorption peak of fullerene C60 occurs then shifts towards the long-wave region. The excitation energy decrease and the excitation wavelength increase correspondingly, and external electric ?eld makes fullerene C60 absorb energy from 1.01 to 2.31 eV in theory. The energy gap decreases drastically from 2.74 to 1.38 eV, which contributed to tune the energy gap of fullerene C60 by the effect of the electric ?eld in a wide range. It is possible to use electric ?eld to tune fullerene C60 into new energy storage material.
关键词： External electric ?eld,Excited state,Cluster,IR spectrum,Fullerene C60
更新于2025-09-23 15:23:52
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Influences of sol-gel progress on luminescent properties of Li <sub/>1.0</sub> Nb <sub/>0.6</sub> Ti <sub/>0.5</sub> O <sub/>3</sub> :Eu <sup>3+</sup> red phosphor
摘要： Li1.0Nb0.6Ti0.5O3:3wt.%Eu3+ red phosphor was synthesized by sol-gel method. The influences of the pH value and the citric acid(CA)/ metal cations(M) ratio on the luminescent properties of the samples were discussed. The properties of the samples were characterized by X-ray diffraction(XRD) and photoluminescence spectroscopy, respectively. The results showed that the samples were consist of “M- phase”. Under the 466nm excitation, the orange emission at 592nm and the red emission at 612nm could be observed. The emission intensity increased with the increasing of pH value firstly and then decreased. The optimum pH value was 5.5. Moreover, the emission intensity decreased with the increasing of CA/M ratio. The relatively high emission intensity of the sample could be obtained when the CA/M was 3:1. Emission spectra and CIE coordinate of Li1.0Nb0.6Ti0.5O3:3wt.% Eu3+ were superior to commercial red phosphor Y2O3:Eu3+,which showed the red phosphor could have potential application in the White-LED field.
关键词： the red phosphor,Eu3+-doped,emission spectrum,Sol-gel method
更新于2025-09-23 15:23:52
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[IEEE 2018 19th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - Erlagol (Altai Republic), Russia (2018.6.29-2018.7.3)] 2018 19th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - Evaluation of Hall Effective Masses in Callium Arsenide Monocrystal in Quantizing Magnetic Field
摘要： Results of calculation of the holes effective masses values in a 3D GaAs monocrystal in a quantizing magnetic field are presented, the masses were evaluated using perturbation theory in the proximity of the point for the magnetic field oriented along [001] crystallographic direction. The masses were calculated for the Landau levels n = 0,1. The condition for application of the considered holes effective mass spectrum for thin monocrystalline films is formulated.
关键词： magnetic field,holes spectrum,holes masses
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Saint Petersburg, Russia (2018.10.22-2018.10.23)] 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Study of Oxyfluoride Glasses with Silver Molecular Clusters for Application in Sensoric and Optoelectronics
摘要： Temperature sensitivity of Oxyfluoride glasses with molecular silver clusters and samarium ions were studied. The experimental procedure for obtaining luminescence spectra at various temperatures is described. The perspective of using oxyfluoride glasses in fiber-optic temperature sensors is considered.
关键词： sensitive element,luminescence,Fiber-optical temperature sensor,oxyfluoride glass,spectrum,molecular clusters of silver
更新于2025-09-23 15:23:52
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Spectra (UV-Visible, IR transmission) of Sc3+, Fe3+ and Cu2+ tri-doped LiNbO <sub/>3</sub> crystals with various [Li]/[Nb] ratios
摘要： The Sc:Fe:Cu:LiNbO3 crystals were grown with Fe3+(0.3 wt.%), Cu2+(0.1 wt.%) and Sc3+(1 mol.%) by the Czochralski method with various [Li]/[Nb] ratios (0.946, 1.05, 1.20 and 1.38). The influence of the [Li]/[Nb] ratios on the defect structure of Sc:Fe:Cu:LiNbO3 crystals was analyzed by the UV-Visible spectra and IR transmission spectra. The spectra show that the absorption edge shift to the red with [Li]/[Nb] ratios enhancing. The Sc:Fe:Cu:LiNbO3 crystals with [Li]/[Nb] ratio of 1.05 is nearly stoichiometric. A new narrow OH- associated vibrational peak at 3505 cm-1 was revealed in Sc:Fe:Cu:LiNbO3 crystals with the ratio of [Li]/[Nb] = 1.38. It is attributed to the (Sc2-Nb)-(OH)-. The results show that the defect structure changes with the [Li]/[Nb] ratios variation.
关键词： IR transmission spectrum,Sc:Fe:Cu:LiNbO3 crystal,UV-Visible spectrum
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference of the Biometrics Special Interest Group (BIOSIG) - Darmstadt (2018.9.26-2018.9.28)] 2018 International Conference of the Biometrics Special Interest Group (BIOSIG) - A benchmark database of visible and thermal paired face images across multiple variations
摘要： Although visible face recognition systems have grown as a major area of research, they are still facing serious challenges when operating in uncontrolled environments. In attempt to overcome these limitations, thermal imagery has been investigated as a promising direction to extend face recognition technology. However, the reduced number of databases acquired in thermal spectrum limits its exploration. In this paper, we introduce a database of face images acquired simultaneously in visible and thermal spectra under various variations: illumination, expression, pose and occlusion. Then, we present a comparative study of face recognition performances on both modalities against each variation and the impact of bimodal fusion. We prove that thermal spectrum rivals with the visible spectrum not only in the presence of illumination changes, but also in case of expression and poses changes.
关键词： visible spectrum,thermal spectrum,pose,score-level fusion,sensor-level fusion,occlusion,expression,illumination,face database
更新于2025-09-23 15:22:29
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A Performance Comparison of Centralized and Distributed Spectrum Management Techniques in Elastic Optical Networks
摘要： Elastic optical networks (EONs) have emerged to provide higher spectrum efficiency than traditional Dense Wavelength-Division-Multiplexing (DWDM) by utilizing enabling technologies such as flexible spectrum grid, Orthogonal Frequency Division Multiplexing (OFDM), and distance adaptive rate and modulation. The choice of the control-plane is an important consideration when deploying any new technology, especially in optical networks. This paper considers generic distributed and centralized spectrum assignment policies in conjunction with the accompanying connection set-up signaling protocols in EONs. A network simulator for Generalized Multiprotocol Label Switching (GMPLS) was developed with Forward Reservation Protocol and Backward Reservation Protocol signaling methods. These signaling techniques are used with the First Fit (FF) and Random Fit (RF) Routing and Spectrum Allocation (RSA) algorithms. The paper discusses control elements (central and distributed architectures) decisions under busy hour and normal network conditions and presents a comprehensive performance analysis of key performance metrics such as connection success rate, connection establishment time, and capacity requirement.
关键词： distributed control,signaling protocols,GMPLS,routing and spectrum allocation,centralized control,spectrum allocation,Elastic optical networks
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference and Exposition on Electrical And Power Engineering (EPE) - Iasi, Romania (2018.10.18-2018.10.19)] 2018 International Conference and Exposition on Electrical And Power Engineering (EPE) - Analysis of Light Design in the Lighting Laboratory of the Riga Technical University
摘要： Given the fact that it is required to increase the efficiency of energy consumption in the premises, it is necessary to develop an effective lighting design that can be used both in old buildings and in new projects. To achieve a lower overall energy consumption by a building without sacrificing the quality of lighting, effective lighting modeling is needed, which allows to obtain reliable results for models as close as possible to real life, taking into account energy-saving lighting devices, integration of daylight in order to reduce energy consumption and maintenance costs, etc. The research evaluates possibility to measure luminance of light sources and detect sources of glare, using ordinary digital single-lens reflex camera (DSLR) and image editing software. Methodology and workflow is presented. The results then are discussed and ways to improve the accuracy of the measurements are highlighted.
关键词： visible spectrum,light measurements,digital camera,fluctuations,Dialux,glare
更新于2025-09-23 15:22:29