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oe1(光电查) - 科学论文

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出版时间
  • 2019
  • 2018
  • 2015
研究主题
  • low-temperature electronics
  • junction field-effect transistors
  • Bessel Function
  • Coupling Coefficient
  • Fusion temperature and Elongation speed
  • Infrared Thermography
  • Statistical Analysis
  • Mean Temperature Difference
  • Surface temperature distribution
  • Diabetic Foot Complications
应用领域
  • Optoelectronic Information Science and Engineering
  • Electronic Science and Technology
  • Physics
机构单位
  • Don State Technical University
  • China Jiliang University
  • UIN Suska Riau
  • BMS College of Engineering
  • Dalhousie University
  • Majmaah University
  • Soochow University
  • University of Riau
  • Karnataka Institute of Endocrinology and Research (KIER)
  • Southern Federal University
1238 条数据
?? 中文（中国） ▾

  • [IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A 120 GHz LTCC Packaged Horn Antenna with a Radome and Soft Surface Structure

    摘要： A 120 GHz step-profiled horn antenna integrated in low-temperature co-fired ceramic (LTCC) packages with a radome is presented in this paper. As an antenna-in-package (AiP) design, the proposed hollow horn structure is constructed by the cavities with several surrounding fences of vertical metallic vias in multilayer LTCC substrates. In consideration of the practical application, co-design with a thick cylindrical radome attached to the surface of the antenna is also studied. A planar soft surface structure in electromagnetics around the horn antenna is introduced so as to suppress the propagation of surface waves inside the radome and thus improve the gain performance. The simulated results indicate that more than 9 GHz bandwidth of -10 dB return loss and a gain of 12.56 dBi in the radiation direction at 0θ= ? are obtained.

    关键词： horn antenna,soft surface,Antenna-in-package (AiP),low-temperature co-fired ceramic (LTCC),radome

    更新于2025-09-04 15:30:14

  • [ASME ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering - Madrid, Spain (Sunday 17 June 2018)] Volume 11B: Honoring Symposium for Professor Carlos Guedes Soares on Marine Technology and Ocean Engineering - Investigation on Temperature Compensation of Fiber Bragg Grating Sensors for Hull Monitoring

    摘要： Hull monitoring system with Fiber Bragg Grating (FBG) sensors increasingly receives people's attentions. However, for the ship hull monitoring, the deformation of hull girder changes a lot as is subjected to a huge temperature variation. Therefore, the compensation method with only FBG temperature self-correction is not suitable for the hull monitoring sensors because no material thermal expansion effects are reasonably included. In this paper, the new compensation method of hull monitoring FBG sensor based on the sensor theory with both FBG temperature self-correction and steel thermal expansion effects correction is studied. The coupled compensation method suitable for hull monitoring sensor is obtained by theoretical derivation. As the comparison, the coupled compensation experiment was carried out. The results show that the relative error under the temperature compensation method is large in the case of drastic strain and temperature changes, and the correction results of the tested method will be closer to the true level.

    关键词： temperature compensation,coupled compensation method,steel thermal expansion,hull monitoring,Fiber Bragg Grating (FBG) sensors

    更新于2025-09-04 15:30:14

  • Low-temperature homoepitaxial growth of two-dimensional antimony superlattices in silicon

    摘要： The authors present a low-temperature process for the homoepitaxial growth of antimony superlattices in silicon. The all low-temperature superlattice doping process is compatible as a postfabrication step for device passivation. The authors have used low-temperature molecular beam epitaxy to embed atomically thin (2D), highly concentrated layers of dopant atoms within nanometers of the surface. This process allows for dopant densities on the order of 1013–1014 cm?2 (1020–1021 cm?3); higher than can be achieved with three-dimensional doping techniques. This effort builds on prior work with n-type delta doping; the authors have optimized the growth processes to achieve delta layers with sharp dopant profiles. By transitioning from a standard effusion cell to a valved cracker cell for antimony evaporation, the authors have achieved carrier densities approaching 1021 cm?3 with peak distribution at ～10 ? FWHM for single delta layers. Even at the highest dopant concentrations studied, no deterioration in carrier mobility is observed, suggesting the upper limit for dopant incorporation and activation has not yet been met. The authors will discuss the details related to growth optimization and show results from in situ monitoring by electron diffraction. They will also report on elemental and electrical characterization of the films.

    关键词： silicon,molecular beam epitaxy,surface passivation,homoepitaxial growth,delta doping,low-temperature,antimony superlattices

    更新于2025-09-04 15:30:14

  • Mobility Enhancement in Polycrystalline Silicon Thin Film Transistors due to the Dehydrogenation Mechanism

    摘要： We investigated the mechanism of mobility enhancement after the dehydrogenation process in polycrystalline silicon (poly-Si) thin films. The dehydrogenation process was performed by using an in-situ CVD chamber in a N2 ambient or an ex-situ furnace in air ambient. We observed that the dehydrogenated poly-Si in a N2 ambient had a lower oxygen concentration than the dehydrogenated poly-Si annealed in an air ambient. The in-situ dehydrogenation increased the (111) preferred orientation of poly-Si and reduced the oxygen concentration in poly-Si thin films, leading to a reduction of the trap density near the valence band. This phenomenon gave rise to an increase of the field-effect mobility of the poly-Si thin film transistor.

    关键词： Low-temperature poly silicon,Crystallization,Dehydrogenation,Thin film transistor

    更新于2025-09-04 15:30:14

  • Strategic Selection of the Oxygen Source for Low Temperature-Atomic Layer Deposition of Al <sub/>2</sub> O <sub/>3</sub> Thin Film

    摘要： The influence of two oxygen source types, H2O and O3, on residual C-related impurities in atomic-layer-deposited (ALD) Al2O3 film is systematically examined. ALD Al2O3 film grown using H2O contains negligible C-related impurities irrespective of growth temperature. However, the C-related impurity in film grown using O3 exhibits strong dependence on growth temperature; only Al carbonate (Al-CO3) is present in film grown at 300 °C, but C-related impurities with lower oxidation states, such as Al-COOH and Al-CHO, appear as the temperature decreases to 150 °C. This suggests that the reactivity of O3 and H2O in the ALD process has a different temperature dependence; from a residual impurity perspective, compared to O3, H2O is a beneficial oxygen source for low temperature processes. Electrical properties, such as charge trapping and gate leakage current, are also examined. For a growth temperature of 300 °C, the film grown using O3 is slightly superior to the film grown using H2O due to its high film density. However, the film grown using H2O demonstrates better electrical characteristics at low growth temperature, 150 °C.

    关键词： oxygen source,atomic layer deposition,low temperature process,ozone,water

    更新于2025-09-04 15:30:14

  • Enhanced Temperature Stability and Defect Mechanism of BNT-Based Lead-Free Piezoceramics Investigated by a Quenching Process

    摘要： Because of the environmental concerns of eliminating lead from piezoelectric products, bismuth-based perovskite is becoming one of the most potential candidates. However, its relatively low thermal depolarization temperature (Td) is still an imperative obstacle hindering implementation of this material for practical application. Here, an enhanced temperature stability of 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 (BNTBT6) piezoceramics is reported, which can be obtained by the effective quenching process. Quenching process enhances the depolarization temperature to 136 °C, which is 40 °C higher than that of normal sintered samples. By using X-ray photoelectron spectroscopy and electron paramagnetic resonance methods, it is revealed that oxygen vacancy may exist in the quenched samples and consequently pins the domain walls, resulting in significant enhancement of depolarization temperature. Temperature-dependent dielectric, piezoelectric, and ferroelectric behaviors are measured as criteria to evidence the enhanced temperature stability.

    关键词： lead-free BNT,quenching,defect mechanism,depolarization temperature

    更新于2025-09-04 15:30:14

  • Finite Element Simulation of Temperature and Stress Field for Laser Cladded Nickel-Based Amorphous Composite Coatings

    摘要： In this paper, a nickel-based amorphous composite coating was obtained on the carbon steel surface by the laser cladding process. The thermal ?eld and stress distribution were simulated by using ANSYS ?nite element software where the moving heat source and powder feeding were modelled by the “Element birth and death” method. The simulation results were veri?ed by comparing the cross-sectional pro?le of fusion lines and X-ray stress measurements, respectively. The results on thermal ?eld showed that the cooling rate of the coating could reach up to 10389.15 K/s and it gradually decreased from the outside surface to the interior, which promoted the formation of amorphous phase. The simulated stress ?eld showed that the coating was in the state of tensile stress after cladding and the longitudinal stress was larger than the transverse stress. The coating was experienced with tensile plastic deformation along the laser scanning direction, which resulted in longitudinal residual stress. A higher stress concentration was occurred between the coating layer and substrate, which increased the susceptibility of crack formation. The test results on transverse residual stress were generally consistent with the simulation. On the contrary, the measured longitudinal stress was nearly close to zero, which was not in agreement with the model due to the formation of cracks.

    关键词： stress ?eld,temperature ?eld,laser cladding,amorphous,numerical simulation

    更新于2025-09-04 15:30:14

  • High-temperature tungsten trioxides obtained by concentrated solar energy: physicochemical and electrochemical characterization

    摘要： High-crystalline tungsten trioxides (WO3) have been synthesized by an environmentally friendly method using concentrated solar energy. The obtained tungsten trioxides (WO3) at three different temperatures and two oxygen mole fractions used for the highest synthesis temperature were characterized by XRD, SEM, and XPS. Higher crystallinity and concentration of W5+ was observed in tungsten trioxides as the synthesis temperature increased. Nevertheless, despite of the different synthetic conditions used, a mixture of two different crystalline structures was observed in all solar-prepared tungsten trioxides: monoclinic and triclinic. Comparing oxides obtained at 1000 °C, higher concentration of W5+ and more defects were found when using lower oxygen molar fraction (WO3-1000-2). Their electrochemical performance was evaluated using cyclic voltammetry (CV) in a conventional three-electrode cell in the following three aqueous electrolytes: acidic, alkaline, and neutral media. In the acidic medium, all the tungsten trioxides showed a capacitive behavior, which was enhanced for oxides obtained at 1000 °C due to a mixed valence of W. On the other hand, in the alkaline medium, a catalytic behavior was detected with higher activity towards hydrogen evolution reaction for the oxide with more defects, higher crystallinity, and monoclinic phase, obtained at 1000 °C and a lower oxygen molar fraction in the synthesis. Finally, in the neutral medium, the oxides synthesized at 1000 °C presented a capacitive behavior whereas the oxides prepared at the lowest temperatures (600 and 800 °C) presented electrochemical processes related to a catalytic behavior for water reduction, which must correspond to their minor concentration of defects, as confirmed by XPS.

    关键词： High-temperature synthesis,Concentrated solar energy,Green synthesis,WO3,Tungsten trioxides

    更新于2025-09-04 15:30:14

  • Comprehensive Remote Sensing || Land Surface Temperature Product Development for JPSS and GOES-R Missions

    摘要： Land surface temperature (LST) is defined by the International LST and Emissivity Working Group as a measure of how hot or cold the surface of the Earth would feel to the touch. For ground-based, airborne, and space-borne remote sensing instruments it is the aggregated radiometric surface temperatures of all components within the sensor’s field of view in the direction of observation, or 'ensemble directional radiometric temperature.' As one of the most important parameters in the weather and climate system controlling surface heat and water exchange between the land and the atmosphere (Yu et al., 2012), LST has recently been listed as one of the Essential Climate Variables (ECVs) by the Global Climate Observation System (GCOS) of the World Meteorological Organization (WMO). Knowledge of the LST provides information on the temporal and spatial variations of the surface equilibrium state and is of fundamental importance in many applications (Li et al., 2013). This thermodynamic variable has been widely used in a variety of fields such as numerical weather prediction models and data assimilation systems (Meng et al., 2009; Zheng et al., 2012; Trigo et al., 2015), evapotranspiration evaluation (Sun et al., 2012; Galleguillos et al., 2011), irrigation and hydrological cycle particularly agricultural drought monitoring (Anderson et al., 2011, 2012; Karnieli et al., 2010), and urban heat island monitoring (Rajasekar and Weng, 2009; Weng et al., 2004).

    关键词： ABI,LST Retrieval,Satellite LST Assessment,Land Surface Temperature,GOES-R,Split-Window Technique,Remote Sensing,VIIRS,JPSS

    更新于2025-09-04 15:30:14

  • Shock induced damage and fracture in SiC at elevated temperature and high strain rate

    摘要： Large-scale molecular dynamics simulations are used to investigate shock-induced damage and fracture in 3C-SiC single crystals at an elevated initial temperature of 2000 K and a high tensile strain rate of ~1010 s-1. Three crystal orientations have been evaluated: [001], [110] and [111]. A comprehensive comparison has been made between cases at 2000 K and at 300 K to address the effects of high temperature on the mechanical performance of SiC under shock loading. Results show that for shock compression, the high temperature decreases the longitude elastic wave speeds as well as the shock stresses. The shock-induced plasticity is mainly in the form of deformation twinning at 300 K, but twinning is absent at 2000 K. The high temperature decreases the structural phase transition threshold pressure in SiC from ~90 GPa at 300 K (for all three orientations) to ~75 GPa in [001], ~57 GPa in [110] and ~64 GPa in [111] at 2000 K, with corresponding particle velocities of 2.75 km/s, 2.0 km/s, and 2.25 km/s, respectively, in agreement with trends observed in recent experiments. The spall fracture behavior reveals that high temperature reduces the spall strength with an average spall strength of ~20.7 GPa in [001], ~21.4 GPa in [110] and ~22.5 GPa in [111] at 2000 K in the classical spall regime, which are about 33% lower than strengths measured at 300 K. However, in the micro-spall regime the spall strengths are very similar at both temperatures. The corresponding thresholds of particle velocity to trigger spall decrease at elevated temperature except for [001] loading, as well as the thresholds for generating overdriven phase transition waves.

    关键词： Structural phase transformation,High temperature,Silicon carbide,Plasticity,Spall

    更新于2025-09-04 15:30:14