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[IEEE 2018 IEEE International Conference on Semiconductor Electronics (ICSE) - Kuala Lumpur (2018.8.15-2018.8.17)] 2018 IEEE International Conference on Semiconductor Electronics (ICSE) - Effect of Different Metal Contact Distance and Light on Electrical Properties of Calcium Carbonate Thin Film
摘要： CaCO3 is an inorganic substance with low toxicity. Electrical properties of CaCO3 is rarely reported although it has promising potential as biosensor. Therefore it is our aim to provide information on CaCO3 electrical properties. This work described the effect of different distance of metal contact pad and also the effect of light to the electrical conductivity of CaCO3. CaCO3 thin film was prepared at 1.0M by gas diffusion method. From the results, the value of current is not affected by different distance of metal contact pad. Results showed conductivity of CaCO3 thin films were not affected by the presence of light. Therefore CaCO3 thin film conductivity is stable and suitable for wide application and further study such as for biosensor.
关键词： CaCO3 Thin Film,Concentration,CaCO3 Electrical Properties,Gas Diffusion,Metal Pad Distance
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 - Retrieval and Validation of Sea Ice Concentration from AMSR-E/AMSR2 in Polar Regions
摘要： Sea ice concentration (SIC) is an important sea ice parameter of the atmosphere-ice-ocean system in the polar region. Daily 6.25 km AMSR-E/AMSR2 SIC from Bremen University (UB) is one of the widely used SIC products. In this paper, MODIS data and aerial image are used to validate this product. The results show that the daily mean AMSR-E ASI products underestimate SICs about 17.9% based on the aerial image, and underestimate SICs about8.5% based on MODIS image. The sea ice extent (SIE) and sea ice area (SIA) which are derived from SIC by ASI algorithm, Dynamic Tie-point ASI algorithm (DT-ASI) as well as NT algorithm are compared.
关键词： Retrieval,Validation,aerial image,Sea ice concentration,AMSR-E,MODIS
更新于2025-09-23 15:22:29
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Ambient Tracer-LIF for 2-D quantitative measurement of fuel concentration in gas jets
摘要： A novel ambient tracer LIF technique with addition of tracer into ambient gas is proposed in this study to quantitatively measure the two dimensional (2-D) fuel concentration distribution in high-pressure gas jets. Firstly, the fundamental principle of the ambient tracer-LIF technique is described, and the equation of fuel concentration in a jet is deduced from the ambient fluorescence intensity. In the ambient tracer-LIF technique, the on-site calibration can be performed, and much more degrees of freedom in selection of tracers or target fuels can be achieved in principle. Then, the experiments are carried out with the high pressure gas injected into the environment doped with acetone in an optical accessible constant volume vessel. The fluorescence in the ambient is induced by using the 266 nm laser, and is recorded by the ICCD camera. The dedicated image processing is implemented to reduce the uncertainty and obtain the quantitative fuel concentration distribution in the jet. The uncertainties of the measurement results are evaluated, including both the systematic and random errors. The uncertainty propagation analysis shows that the measurement uncertainty increases with the local fuel concentration decreasing, and at the boundary regions of the jet, where the mixture is over lean, the relative uncertainty goes up to 26%. Finally, the temporal variations of the fuel concentration distribution in the gas jet are presented, and the effects of injection pressure are discussed. These results are believed to be valuable for development of numerical models and combustion system designs.
关键词： 2-D quantitative concentration measurement,On-site calibration,Ambient tracer-LIF,Natural gas direct injection
更新于2025-09-23 15:22:29
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Photoluminescence Characteristics of Sm3+-doped LnBWO6 (Ln=La, Gd and Y) as New Orange-red Phosphors
摘要： A series of Sm3+-doped LnBWO6 (Ln=La, Gd and Y) phosphors with orange-red light emitting in pure phase were prepared by high temperature solid-state process. The crystal structure, photoluminescence properties, decay lifetimes and thermal stability properties of those as-prepared samples were investigated. Those phosphors can be efficiently excited by near-UV and blue light and emitted orange-red luminescence with color coordinates (0.622, 0.377). Among those LnBWO6 (Ln=La, Gd and Y) hosts, the emission intensities of Sm3+-doped LaBWO6 are the strongest ones. The optimum doping concentration and critical energy transfer distance of Sm3+ ions in LaBWO6 were determined. The fluorescence concentration quenching mechanism was attributed to the dipole-dipole interaction between the Sm3+ ions. The fluorescent thermal quenching studies showed Sm3+ doped LaBWO6 had high thermal-stable properties. The present work suggested that Sm3+-doped LnBWO6 (Ln=La, Gd and Y) as orange-red phosphors exhibited potential application in white LED.
关键词： red phosphors,concentration quenching,energy transfer,white LEDs,luminescent properties
更新于2025-09-23 15:22:29
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Near White Light Emission and Concentration Quenching of Calcium Titanate Doped with Dysprosium (III) Phosphors
摘要： This paper reports the preparation of CaTiO3 doped with various concentrations of Dysprosium (II) using solid state reaction technique. X-ray diffraction patterns of the sample were taken. Observed XRD pattern was matched using software match2!. The pattern was matched significantly with the crystallographic open database card (COD – 96-101-1212) which is a standard card for CaTiO3. This matching exhibited that, the prepared sample is cubic in structure with space group P m ? 3 m (221). Photoluminescence (PL) studies of the samples were also done. PL intensity was found increasing with increasing dopant concentration and maximum intensity was noted at 2.0 mol% concentration of Dy3+, thereafter concentration quenching occurred. Emission Peaks were centered at 483 nm (4F9/2?6H15/2) and 576 nm (4F9/2?6H13/2) respectively. For studying the concentration quenching, the critical distance for energy transfer and electric multipolar character were estimated. The value of multipolar character expressed that, the transition in emission spectra is a dipole – dipole (d-d) transition. Commission Internationale de l’éclairage (CIE) coordinates was found as (0.36, 0.39), which is near to white light. Colour Correlated Temperature (CCT) was 4489 K which was indicative of cool appearance of the light emitted.
关键词： White LED,Concentration quenching,Photoluminescence
更新于2025-09-23 15:22:29
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Effects of reaction conditions on light-dependent silver nanoparticle biosynthesis mediated by cell extract of green alga Neochloris oleoabundans
摘要： Silver nanoparticles (AgNPs) were synthesized by incubating the mixture of AgNO3 solution and whole-cell aqueous extracts (WCAEs) of Neochloris oleoabundans under light conditions. By conducting single-factor and multi-factor optimization, the effects of parameters including AgNO3 concentration, pH, and extraction time were quantitatively evaluated. The optimal conditions in terms of AgNP yield were found to be 0.8 mM AgNO3, pH 5, and 9-h extraction. The AgNPs thus synthesized were quasi-spherical with a mean particle diameter of 16.63 nm and exhibited decent uniformity as well as antibacterial activities, which may facilitate AgNP biosynthesis’s application in the near future.
关键词： Extraction time,Biosynthesis,Silver nanoparticles,Light-dependent reaction,AgNO3 concentration,pH,Microalgae
更新于2025-09-23 15:21:21
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Increased luminescent efficiency of perovskite light emitting diodes based on modified two-step deposition method providing gradient concentration
摘要： We increased the luminescent efficiency of perovskite light-emitting diodes (PeLEDs) by using a modified two-step deposition method combined with an interdiffusion process without additional solvent engineering or additive molecules. Methylammonium lead bromide (MAPbBr3) polycrystalline films with nanosized grains and low electronic disorder were fabricated by a modified two-step deposition process. The as-fabricated MAPbBr3 films showed gradient concentration characteristics as a result of a gradient distribution of the MABr. Also, the MABr-gradient concentration structure was intensified by the interdiffusion process, showing improved performance of MAPbBr3 PeLEDs with maximum current efficiency CEmax = 0.861 cd A?1 and maximum luminance = 604 cd m?2 with very narrow electroluminescence spectral width. This is the highest CEmax among MAPbBr3-based PeLEDs deposited by the two-step deposition method.
关键词： two-step deposition method,perovskite light-emitting diodes,luminescent efficiency,gradient concentration,interdiffusion process
更新于2025-09-23 15:21:21
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Effect of crucible and crystal rotations on the solute distribution in large size sapphire crystals during Czochralski growth
摘要： In this study, the ?ow, temperature and solute concentration ?elds in the melt during the CZ growth process are numerically investigated. The results show that the magnitude and distribution of the solute concentration in the melt is strongly affected by the convective ?ow and thermal distribution. The maximum solute concentration always occurs at the crucible sidewall where the maximum temperature in the melt is found and the solute concentration at the crystal-melt interface increases from the triple point to the centerline. Heat transport from the side crucible wall towards the crystal-melt interface is enhanced by the crucible rotation. The level of the solute concentration inside the melt is reduced due to the lowering of the maximum temperature at the crucible wall. As a consequence, the distribution of the solute concentration along the crystal-melt interface becomes smaller and more uniform as the crucible rotation rate increases. However, after the crucible rotation rate becomes large enough, the maximum solute concentration and the solute concentration along the crystal-melt interface start to increase. Heat transport inside the melt is also affected by the crystal rotation. The centrifugal force induced by the crystal rotation generates a vortex below the crystal-melt interface. This vortex gets larger and stronger as the crystal rotation rate increases. In the smaller crystal rotation rate regime, this vortex is very small, suppressing the solute concentration at the crystal-melt interface. Therefore, the solute concentration along the crystal-melt interface becomes less when the crystal rotation rate is higher, although there is an increase in the maximum solute concentration in the melt due to the higher maximum temperature. In the higher crystal rotation rate regime, there is a reduction in the convexity of the crystal-melt interface due to enhancement of heat transport from the bottom wall of the crucible by vortex motion under the crystal-melt interface. Therefore, there is a switch to an increase in the transport of solute impurities into the crystal-melt interface. Hence, the solute concentration along the crystal-melt interface increases as the crystal rotation rate increases. However, with a further increase in the crystal rotation rate, as the shape of the crystal-melt interface changes becoming concave towards the melt, the solute concentration along the crystal-melt interface decreases because the maximum temperature is signi?cantly reduced. In this study, both counter- and iso-rotations are considered. The results of a comparison of the cases of iso- and counter-crystal rotation show that the lowest and most uniform solute distribution along the crystal-melt interface is achieved when there is no crystal rotation and the crucible rotation rate is ?xed at 1 rpm. In other words, the lowest and most uniform solute concentration can be achieved with the only crucible rotation.
关键词： Solute concentration,Czochralski method,Sapphire,Numerical simulation,Crucible and crystal rotations
更新于2025-09-23 15:21:21
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Ultrathin Y <sub/>2</sub> O <sub/>3</sub> :Eu <sup>3+</sup> nanodiscs: spectroscopic investigations and evidence for reduced concentration quenching
摘要： Here, we report the synthesis and spectral properties of ultrathin nanodiscs (NDs) of Y2O3:Eu3+. It was found that the NDs of Y2O3:Eu3+ with a thickness of about 1 nm can be fabricated in a reproducible, facile and self-assembling process, which does not depend on the Eu3+ concentration. The thickness and morphology of these NDs were determined with small angle x-ray scattering and transmission electron microscopy. We found that the crystal field in these nanoparticles deviates from both the cubic and monoclinic characteristics, albeit the shape of the 5D0 → 7FJ (J = 0, 1, 2) transitions shows some similarity with the transitions in the monoclinic material. The Raman spectra of the non-annealed NDs manifest various vibration modes of the oleic acid molecules, which are used to stabilise the NDs. The annealed NDs show two very weak Raman lines, which may be assigned to vibrational modes of Y2O3 NDs. The concentration quenching of the Eu3+ luminescence of the NDs before annealing is largely suppressed and might be explained in terms of a reduction of the phonon density of states.
关键词： nanodiscs,small angle x-ray scattering,europium-doped yttrium oxide,Raman spectroscopy,concentration quenching,transmission electron microscopy,luminescence
更新于2025-09-23 15:21:21
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Quantification of Vortex Generation Due to Non-Equilibrium Electrokinetics at the Micro/Nanochannel Interface: Spectral Analysis
摘要： We report on our investigation of a low Reynolds number non-equilibrium electrokinetic ?ow in a micro/nanochannel platform. Non-equilibrium electrokinetic phenomena include so-called concentration polarization in a moderate electric ?eld and vortex formation in a high electric ?eld. We conducted a spectral analysis of non-equilibrium electrokinetic vortices at a micro/nanochannel interface. We found that periodic vortices are formed while the frequency varies with the applied voltages and solution concentrations. At a frequency as high as 60 Hz, vortex generation was obtained with the strongest electric ?eld and the lowest concentration. The power spectra show increasing frequency with increasing voltage or decreasing concentration. We expect that our spectral analysis results will be useful for micromixer developers in the micromachine research ?eld.
关键词： spectral analysis,concentration polarization,micromixer,Vortex generation,electrokinetics,micro/nanochannel
更新于2025-09-23 15:21:21