- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2018
- imgae sensor
- internet of things
- drone
- visible light ID
- Signal-to-Noise Ratio (SNR)
- Infinite Gain Multiple Feedback (IGMF)
- Visible Light Communications (VLC)
- LED
- Trans-Impedance Amplifier (TIA)
- Optoelectronic Information Science and Engineering
- Tohoku University
- University of Northumbria
- University of Huddersfield
-
Review on Li-Fi: an advancement in wireless network communication with the application of solar power
摘要： Light Fidelity, commonly referred to as Li-Fi is a technology that was introduced by a German physicist called Herald Hass. This technology in its own uniqueness considers the use of light (Light Emitting Diode, LED to be specific) as its medium of delivering high speed communication that complies with standard IEEE 802.15.7 bidirectional communication standard. This optical means of communications is also known as visible light communication. It is safer when compared with Wi-Fi network. This paper will focus on Li-Fi applications, comparison with existing technologies like Wi-Fi and the inclusion of an alternative source of power i.e., solar power, as a means of effectively optimizing on the availability and accessibility of the benefits in places where erratic or total power outage is a common trend.
关键词： solar power,Visible Light Communication (VLC),Li-Fi,Wi-Fi
更新于2025-09-04 15:30:14
-
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
-
Residual stress in underlying silicon at the fixed end of SiO <sub/>2</sub> microcantilevers?— A micro-Raman study
摘要： In this work, nature of the residual stress developed in the convex corners created in underlying Si at the fixed end of SiO2 microcantilevers (MCs) fabricated by wet chemical etching method was investigated using micro-Raman spectroscopy with visible excitation. It revealed the presence of tensile stress near the sharp edge of the convex corner and is attributed to the localized stress generated in the neighborhood of the discontinuities, acting as stress concentration region. Residual stress estimated by micro-Raman technique across the convex corner was also validated by FEM simulations. Micro-Raman also revealed the presence of tensile stress on the etched Si surface, which is explained on the basis of stress induced by native oxide shells covering the etched features.
关键词： SiO2 microcantilever,convex corner in Si,micro-Raman spectroscopy using visible excitation,residual stress
更新于2025-09-04 15:30:14
-
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
-
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
-
A new thermal infrared and visible spectrum images-based pedestrian detection system
摘要： In this paper, we propose a hybrid system for pedestrian detection, in which both thermal and visible images of the same scene are used. The proposed method is achieved in two basic steps: (1) Hypotheses generation (HG) where the locations of possible pedestrians in an image are determined and (2) hypotheses verification (HV), where tests are done to check the presence of pedestrians in the generated hypotheses. HG step segments the thermal image using a modified version of OTSU thresholding technique. The segmentation results are mapped into the corresponding visible image to obtain the regions of interests (possible pedestrians). A post-processing is done on the resulting regions of interests to keep only significant ones. HV is performed using random forest as classifier and a color-based histogram of oriented gradients (HOG) together with the histograms of oriented optical flow (HOOF) as features. The proposed approach has been tested on OSU Color-Thermal, INO Video Analytics and LITIV data sets and the results justify its effectiveness.
关键词： Thermal images,Random forests,Local binary pattern (LBP),Pedestrian detection,Histograms of oriented optical flow (HOOF),Support vector machines (SVMs),Visible images,Histogram of oriented gradients (HOG)
更新于2025-09-04 15:30:14
-
Analysis of gaseous ammonia (NH3) absorption in the visible spectrum of Jupiter - Update
摘要： An analysis of currently available ammonia (NH3) visible-to-near-infrared gas absorption data was recently undertaken by Irwin et al. (Icarus, 302 (2018) 426) to help interpret Very Large Telescope (VLT) MUSE observations of Jupiter from 0.48–0.93 μm, made in support of the NASA/Juno mission. Since this analysis a newly revised set of ammonia line data, covering the previously poorly constrained range 0.5–0.833 μm, has been released by the ExoMol project, “C2018” (Coles et al. 2018), which demonstrates significant advantages over previously available datasets, and providing for the first time complete line data for the previously poorly constrained 5520- and 6475-?A bands of NH3. In this paper we compare spectra calculated using the ExoMol–C2018 dataset (Coles et al. 2018) with spectra calculated from previous sources to demonstrate its advantages. We conclude that at the present time the ExoMol–C2018 dataset provides the most reliable ammonia absorption source for analysing low to medium resolution spectra of Jupiter in the visible/near-IR spectral range, but note that the data are less able to model high-resolution spectra owing to small, but significant inaccuracies in the line wavenumber estimates. This work is of significance not only for solar system planetary physics, but for future proposed observations of Jupiter-like planets orbiting other stars, such as with NASA’s planned Wide-Field Infrared Survey Telescope (WFIRST).
关键词： ammonia,ExoMol,visible spectrum,Jupiter,absorption,WFIRST,VLT,MUSE,C2018,NASA/Juno
更新于2025-09-04 15:30:14
-
Fabrication of highly efficient and hierarchical CdS QDs/CQDs/H-TiO2 ternary heterojunction: Surpassable photocatalysis under sun-like illumination
摘要： Highly efficient and durable visible-light utilized nanocomposites have a vital role in environmental pollutants remediation. Hence, in this study, we have fabricated CdS QDs co-sensitized CQDs/H-TiO2 (Hollow Titania) ternary heterostructures (CdS QDs/CQDs/H-TiO2) in a facile region-selective deposition route. The as-fabricated nanocomposites were evidently characterized by physicochemical techniques. CdS QDs were uniformly distributed on the smooth surface of hierarchical CQDs/H-TiO2 heterojunction. The as-fabricated CdS QDs/CQDs/H-TiO2 nanocomposite has high-performances for efficient degradation efficacy of phenol, MB and RhB which exhibited enhanced degradation activities with rate constants (k) of 0.03, 0.051 and 0.045 min-1, respectively. All these superior photocatalytic activities obviously attributed to the effect of calcination temperature, enhanced photocurrent, minimized recombination of photo-induced charges in the photocatalysis and optimum content of CdS QDs have the distinct basis for the close interfacial connection developing. In addition, evidenced on the arguable results of electron spin resonance and radical-trapping experiments, the primary reactive-oxygen species and a plausible reaction-mechanism for organic pollutants degradation over CdS QDs/CQDs/H-TiO2 were proposed. This creative work is strategically considered an important step to potentially enhance the utilization of TiO2 in various fields as visible light-induced heterojunction.
关键词： Hollow TiO2,CdS QDs/CQDs/H-TiO2,Visible-light photocatalysis,CQDs/H-TiO2,Environmental remediation
更新于2025-09-04 15:30:14
-
Fabrication of Perylene Tetracarboxylic Diimide-Graphitic Carbon Nitride Heterojunction Photocatalyst for Efficient Degradation of Aqueous Organic Pollutants
摘要： Metal-free g-C3N4 is the promising candidate for the next generation visible light-responsive photocatalyst, however, high recombination probability of the photogenerated charge carriers on g-C3N4 limits its photocatalytic activity. To further increase the intrinsic photocatalytic activity of g-C3N4, here perylene tetracarboxylic diimide-g-C3N4 heterojunctions (PDI/GCN) are prepared by one-step imidization reaction between perylene tetracarboxylic dianhydride (PTCDA) and g-C3N4 in aqueous solution. By the combination of various testing results it is confirmed that the surface hybridization of PTCDA and g-C3N4 in the PDI/GCN heterojunctions via O=C?N?C=O covalent bonds occurs at lower PTCDA-to-g-C3N4 weight percentage. By selecting p-nitrophenol and levofloxacin as the target organic pollutants, the visible light photocatalytic performance of the PDI/GCN heterojunctions are studied. It shows that the PDI/GCN heterojunction prepared at PTCDA-to-g-C3N4 weight percentage of 1% exhibits remarkably higher visible light photocatalytic degradation and mineralization ability towards aqueous target pollutants as compared with g-C3N4 and Degussa P25 TiO2. On the basis of the experimental results including photoelectrochemistry, indirect chemical probe and electron spin resonance spectroscopy it is verified that the surface hybridization in the heterojunctions is responsible for this enhanced photocatalytic activity via accelerating the migration and separation of the photogenerated charge carriers, causing to produce more active species like ?O2?, hVB+ and ?OH for deep oxidation of PNP or LEV to CO2 and inorganic anions.
关键词： graphitic carbon nitride,heterojunction,perylene tetracarboxylic diimide,visible light photocatalysis,organic pollutant
更新于2025-09-04 15:30:14
-
DenseFuse: A Fusion Approach to Infrared and Visible Images
摘要： In this paper, we present a novel deep learning architecture for infrared and visible images fusion problem. In contrast to conventional convolutional networks, our encoding network is combined by convolutional layers, fusion layer and dense block in which the output of each layer is connected to every other layer. We attempt to use this architecture to get more useful features from source images in encoding process. And two fusion layers(fusion strategies) are designed to fuse these features. Finally, the fused image is reconstructed by decoder. Compared with existing fusion methods, the proposed fusion method achieves state-of-the-art performance in objective and subjective assessment.
关键词： visible image,image fusion,infrared image,dense block,deep learning
更新于2025-09-04 15:30:14