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[IEEE 2018 3rd International Conference on Pattern Analysis and Intelligent Systems (PAIS) - Tebessa, Algeria (2018.10.24-2018.10.25)] 2018 3rd International Conference on Pattern Analysis and Intelligent Systems (PAIS) - A system for the automatic detection of glaucoma using retinal images
摘要： Glaucoma is an optic neuropathy and it principal cause of blindness in the world. In this paper, a system able to treat and analyze the Visual Field (VF) images and Optical Coherence Tomography of the Ganglion Cell Layer (OCT-GCL) images is proposed, in order to help early detection of glaucoma in its early stages. The proposed approach is based on calculating the percentage of healthy, sick and dead regions of VF and OCT-GCL images. In order to carry out this calculation, we combined the thresholding methods with morphological operators and median filter to extract all regions. These algorithms developed were tested on a set of images of a local database composed of 58 OCT-GCL images and 21 VF images. The results obtained are satisfactory and confirmed by experts in ophthalmology.
关键词： Optical coherence tomography of ganglion cell layer,Segmentation,Visual field,Glaucoma,Characterization
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Landsat 9 Thermal Infrared Sensor 2 Characterization Plan Overview
摘要： Landsat 9 will continue the Landsat data record into its fifth decade with a near-copy build of Landsat 8 with launch scheduled for December 2020. The two instruments on Landsat 9 are Thermal Infrared Sensor-2 (TIRS-2) and Operational Land Imager-2 (OLI-2). TIRS-2 is a two-channel pushbroom imager with a 15-degree field of view that will have a 16-day measurement cadence from its nominal 705-km orbit altitude. Its carefully developed instrument performance requirements and associated characterization plan will result in stable and well-understood science-quality imagery that will be used for environmental, economic and legal applications. This paper will present a summary of the plan for TIRS-2 prelaunch characterization at the component, subsystem, and instrument level.
关键词： prelaunch characterization,calibration,Landsat 9,thermal infrared remote sensing,TIRS-2
更新于2025-09-23 15:22:29
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Synthesis of Graphene Oxide Nanosheets via Modified Hummers’ Method and Its Physicochemical Properties
摘要： The efficient synthesis of exfoliated graphene oxide nanosheets (GO) via modified Hummers’ method was successfully carried out. The physicochemical properties of GO were determined by Fourier transform infrared spectroscopy (FTIR), UV-visible spectrophotometry (UV-vis), x-ray diffraction analysis (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The graphite was fully oxidized by strong oxidizing agent caused the oxygen-containing functional groups such as C-O-C, C=O, and COOH were introduced into the graphite layers as analyzed by Raman and FTIR. XRD pattern of GO showed 2θ of 12.0o with interlayer spacing ~ 7.37A which describe non uniform crystal structure with the addition of oxygen containing functional groups. UV-vis spectrum of GO exhibit maximum absorption peak at ~ 234 nm corresponding to the aromatic C=C bond with π-π* transition. The morphology of GO was observed to have flake-like shape and less transparent layers by TEM. The properties of synthesized GO suggest high potential in producing the high quality of graphene which is can be applied as the electrocatalyst support for direct methanol fuel cell application.
关键词： Graphene oxide nanosheets,characterization,Hummers’ method,graphite,chemical oxidation
更新于2025-09-23 15:22:29
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[IEEE 2018 5th IEEE International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Rome, Italy (2018.6.20-2018.6.22)] 2018 5th IEEE International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Characterization and Testing of a High-Resolution Time-of-Flight Camera for Autonomous Navigation
摘要： This paper presents the results of research activities carried out to characterize and test the operation of a latest generation commercial, high-resolution Time-of-Flight (TOF) camera. The aim is to preliminary evaluate the achievable performance as well as potential limitations related to the use of this instrument for autonomous navigation purposes. Two fields of investigation have been identified: autonomous navigation of Unmanned Aerial Vehicles flying in GPS-denied environments; autonomous relative navigation between non-cooperative space objects. With reference to these applications, first, a metrological characterization has been operated within a laboratory setup. Second, experimental tests have been carried out by processing point clouds acquired by the TOF sensor with state-of-the-art algorithms (for depth-based odometry and non-cooperative pose determination, respectively).
关键词： depth-based odometry,non-cooperative pose determination,TOF camera,autonomous navigation,metrological characterization
更新于2025-09-23 15:22:29
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PZT/PZT and PZT/BiT Composite Piezo-Sensors in Aerospace SHM Applications: Photochemical Metal Organic + Infiltration Deposition and Characterization
摘要： The composition of fine-ground lead zirconate-titanate powder Pb(Zr0.52Ti0.48)O3, suspended in PZT and bismuth titanate (BiT) solutions, is deposited on the curved surface of IN718 and IN738 nickel-based super alloy substrates up to 100 μm thickness. Photochemical metal organic and infiltration techniques are implemented to produce smooth, semi-dense, and crack-free random orientated thick piezoelectric films as piezo-sensors, free of any dopants or thickening polymers. Every single layer of the deposited films is heated at 200 °C with 10 wt.% excess PbO, irradiated by ultraviolet lamp (365 nm, 6 watt) for 10 min, pyrolyzed at 400 °C, and subsequently annealed at 700 °C for one hour. This process is repeated successively until reaching the desired thickness. Au and Pt thin films are deposited as the bottom and top electrodes using evaporation and sputtering methods, respectively. PZT/PZT and PZT/BiT composite films are then characterized and compared to similar PZT and BiT thick films deposited on the similar substrates. The effect of the composition and deposition process is also investigated on the crystalline phase development and microstructure morphology as well as the dielectric, ferroelectric, and piezoelectric properties of piezo-films. The maximum remnant polarization of Pr = 22.37 ± 0.01, 30.01 ± 0.01 μC/cm2, the permittivity of εr = 298 ± 3, 566 ± 5, and piezoelectric charge coefficient of d33 = 126, 148 m/V were measured versus the minimum coercive field of Ec = 50, 20 kV/cm for the PZT/PZT and PZT/BiT thick films, respectively. The thick film piezo-sensors are developed to be potentially used at frequency bandwidth of 1–5 MHz for rotary structural health monitoring and also in other industrial or medical applications as a transceiver.
关键词： piezoelectric sensor,structural health monitoring,PZT/BiT,composite,characterization,sol-gel PMOD deposition,infiltration,aerospace structure,PZT/PZT,thick film
更新于2025-09-23 15:22:29
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Fabrication, Modelling and Assessment of Hybrid 1-D Elastic Fabry Perot Microcavity for Mechanical Sensing Applications
摘要： 1-D multilayer dielectric films consisting of seven pairs of SiO2 and TiO2 alternating layers are deposited on a SiO2 substrate using the radio frequency sputtering technique. The thicknesses of the film layers are chosen to reflect the visible radiation around 650 nm. An elastic microcavity layer made of Polydimethylsiloxane was sandwiched between two Bragg reflectors. A fabrication process was then developed for elastic microcavity in order to tailor the thickness, establish the surface planarity and to increase reproducibility of the samples. Optical transmittance of the single Bragg reflector and the microcavity were both simulated and measured. A comparison between measurement data and Transfer Matrix Method calculations shows a favourable correlation. Furthermore, in order to assess the suitability of the microcavity as a force sensor, transmittance measurements were carried out as a function of the applied forces. The change in the elastic microcavity thickness due to applied forces resulted in cavity resonance peak shifts proportional to the applied forces.
关键词： Optical Characterization and Modelling,Silica and Titania,1D Elastic Photonic Crystal,Mechanical Sensor,RF sputtering,PDMS
更新于2025-09-23 15:22:29
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The flower-like heterostructured Fe2O3/MoS2 coated by amorphous Si-Oxyhydroxides: An effective surface modification method for sulfide photocatalysts in photo-Fenton reaction
摘要： The semiconductor photocatalytic technology is an important approach for solving the energy and environmental problems by only harnessing solar energy. Herein, we employ a facile hydrothermal method to prepare 3D flower-like Fe2O3/MoS2 heterostructures, which perform a high efficient photocatalytic property on photodegrading 20 mg/L methyl blue (MB) solution within 20 min, over 10 times of bare Fe2O3 nanoparticles. In addition, we first propose a surface modification method using amorphous Si-oxyhydroxides (SiOxH) as coating layer to protect the sulfide photocatalysts from corrosion in photo-Fenton reaction. As a result, the SiOxH-Fe2O3/MoS2 nanocomposites show good stability and high efficient decomposition behavior in photo-Fenton reaction, while the MoS2 nanosheets of as-prepared Fe2O3/MoS2 heterostructures without SiOxH modification have been almost all corroded away.
关键词： Photocatalyst,Heterostructure,Characterization,Surface modification.
更新于2025-09-23 15:22:29
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Strain control of GaN grown on Si substrates using an AlGaN interlayer
摘要： To suppress wafer bowing and crack generation of GaN on Si substrates, we investigated the effects of the Al content and thickness of the AlGaN interlayer on the compressive strain in the overlying GaN layer theoretically and experimentally. In the simulation, AlGaN relaxes gradually over the critical thickness. Therefore, the relaxation ratio of AlGaN at the top surface can be defined as a function of Al content and thickness. Too high Al content or too thick AlGaN interlayer induced too large initial strain in the upper GaN layer, which caused rapid and succeeding gradual relaxation, i.e., decrease of strain, of the GaN layer during growth because of generation of threading dislocations. Conversely, low Al content or thin AlGaN interlayer could induce constant but only small strain in the GaN layer. Therefore, the ideal relaxation ratio of the AlGaN surface exists to apply the maximal constant compressive strain in the GaN layer. The relaxation ratios of AlGaN interlayers determined in experiments were much smaller than those calculated in the simulation. Although the measured compressive strain in the GaN layer was smaller than expected, its decrease rate was small when grown on AlGaN interlayers with an almost ideal relaxation ratio.
关键词： Computer simulation,Characterization,Metalorganic vapor phase epitaxy,Stresses,Growth models,Nitrides
更新于2025-09-23 15:22:29
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Synthesis and spectroscopic properties of 1-benzyl-5,6 diamino-2-thiouracil bonded graphene oxide
摘要： Recently, carbon-containing materials such as graphene, fullerene and carbon nanotubes have been investigated in electronic devices and drug delivery system, etc. On the other hand, thiouracil derivative molecules are bonded to such drug delivery systems because of the fact that thiouracil and its derivatives molecules are very important molecules for medicine and pharmacy. In this study we present the synthesis and characterization of graphene oxide (GO) bonded with 1-benzyl-5,6 diamino-2-thiouracil (1B56D2T). Obtained this new material was characterized using various spectroscopic methods such as Fourier Transform Infrared Spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD) and Ultraviolet evisible (UVeVIS). Scanning electron microscopy (SEM) was used to characterize morphology of GO and title molecule bonded GO. Moreover, more information was obtained using thermal analysis. As a result, title molecule bonded GO could be used as a drug delivery system in the treatment of some diseases.
关键词： Spectroscopic methods,Characterization,1-Benzyl-5,6 diamino-2-thiouracil,Graphene oxide
更新于2025-09-23 15:22:29
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High-fidelity probing of the structure and heterogeneity of extracellular vesicles by resonance-enhanced atomic force microscopy infrared spectroscopy
摘要： Extracellular vesicles (EVs) are highly specialized nanoscale assemblies that deliver complex biological cargos to mediate intercellular communication. EVs are heterogeneous, and characterization of this heterogeneity is paramount to understanding EV biogenesis and activity, as well as to associating them with biological responses and pathologies. Traditional approaches to studying EV composition generally lack the resolution and/or sensitivity to characterize individual EVs, and therefore the assessment of EV heterogeneity has remained challenging. We have recently developed an atomic force microscope IR spectroscopy (AFM-IR) approach to probe the structural composition of single EVs with nanoscale resolution. Here, we provide a step-by-step procedure for our approach and show its power to reveal heterogeneity across individual EVs, within the same population of EVs and between different EV populations. Our approach is label free and able to detect lipids, proteins and nucleic acids within individual EVs. After isolation of EVs from cell culture medium, the protocol involves incubation of the EV sample on a suitable substrate, setup of the AFM-IR instrument and collection of nano-IR spectra and nano-IR images. Data acquisition and analyses can be completed within 24 h, and require only a basic knowledge of spectroscopy and chemistry. We anticipate that new understanding of EV composition and structure through AFM-IR will contribute to our biological understanding of EV biology and could find application in disease diagnosis and the development of EV therapies.
关键词： spectroscopy,heterogeneity,nanoscale characterization,AFM-IR,extracellular vesicles
更新于2025-09-23 15:22:29