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- 2019
- charge – discharge energy efficiency
- Lithium-ion battery
- degradation diagnosis
- photovoltaic surplus energy
- working electric vehicle
- Electrical Engineering and Automation
- Ritsumeikan University
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Flame spray pyrolysis synthesized gold-loaded titanium dioxide photocatalyst for degradation of Rhodamine B
摘要： Gold-loaded titanium dioxide (Au-loaded TiO2) was synthesized by the flame spray pyrolysis method for using as photocatalyst. The synthesized Au-loaded TiO2 photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The photocatalytic degradation of Rhodamine B (RhB) dye solution over synthesized Au-loaded TiO2 was studied. The concentration of RhB was determined by UV–Vis spectrophotometry. For the photocatalytic activity, it was found that Au(1.00 mol%)-loaded TiO2 was a better photocatalyst than others under the same reaction conditions. The optimal conditions for photocatalytic degradation of RhB were found to be 0.6 g/L of photocatalyst concentration under UV light irradiation (UV–C 254 nm). The highest kinetic rate constant of photocatalyst was 0.0057 min?1 at the optimum conditions and the mechanism of the photocatalytic process had also been discussed.
关键词： Rhodamine B,Flame spray pyrolysis,Au-loaded TiO2,Degradation,Photocatalyst
更新于2025-09-09 09:28:46
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Investigation on the degradation indicators of short-circuit tests in 1.2?kV SiC MOSFET power modules
摘要： This paper provides a comprehensive investigation on both static characteristics and short-circuit performance of 1.2 kV SiC MOSFET power modules with 2nd generation planar technology. The experimental approach is based on the static characteristics measurements and the short-circuit tests with gradual increase of pulse time duration. If any variation of the static characteristics appears, the time duration of next short-circuit tests would keep the same with the last pulse duration (approach 1) or increase continuously (approach 2). The results of the short-circuit waveforms show a gate degradation which is further con?rmed with the measurement of the gate leakage current. Additionally, other degradation indicators, including positive shift of threshold voltage, drain leakage current and on-state resistance increase are evidenced and discussed in this paper. These can be used for early prediction of the degradation and failure in the short-circuit conditions.
关键词： SiC MOSFET,SiC power module,Short-circuit,Degradation indicators
更新于2025-09-09 09:28:46
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Degradation of GaN-on-GaN vertical diodes submitted to high current stress
摘要： GaN-on-GaN vertical devices are expected to ?nd wide application in power electronics, thanks to the high current densities, the low on-resistance and the high breakdown voltage. So far, only few papers on the reliability of GaN-on-GaN vertical devices have been published in the literature. This paper investigates the degradation of GaN-on-GaN pn diodes submitted to stress at high current density. The study was carried out by means of electrical characterization and electroluminescence (EL) measurements. We demonstrate that: (i) when submitted to stress at high current density, the devices show signi?cant changes in the electrical characteristics: an increase in on-resistance/turn-on voltage, an increase in the generation/recombination components, the creation of shunt-paths. (ii) the increase in on-resistance is strongly correlated to the decrease in the EL signal emitted by the diodes. (iii) the degradation kinetics have a square-root dependence on time, indicative of a di?usion process. The results are interpreted by considering that stress induces a di?usion of hydrogen from the highly-p-type doped surface towards the pn junction. This results in a decrease in hole concentration, due to the creation of MgeH bonds, and in a lower hole injection. As a consequence, on-resistance increases while EL signal shows a correlated decrease.
关键词： Wide band gap semiconductors,Bulk GaN substrates,Vertical diodes,pn junction,Di?usion,Gallium nitride,Hydrogen,Degradation
更新于2025-09-09 09:28:46
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[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing, China (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - A Co-occurrence Background Model with Hypothesis on Degradation Modification for Object Detection in Strong Background Changes
摘要： Object detection has become an indispensable part of video processing and current background models are sensitive to background changes. In this paper, we propose a novel background model using an algorithm called Co-occurrence Pixel-block Pairs (CPB) against background changes, such as illumination changes and background motion. We utilize the co-occurrence “pixel to block” structure to extract the spatial-temporal information of each pixel to build background model, and then employ an efficient evaluation strategy to identify the current state of each pixel, which is named as correlation dependent decision function. Furthermore, we also introduce a Hypothesis on Degradation Modification (HoD) into CPB structure to reinforce the robustness of CPB. Experimental results obtained from the dataset of the PETS2001, AIST-Indoor, SBMnet and CDW-2012 databases show that our model can detect objects robustly in strong background changes.
关键词： co-occurrence pixel-block pairs,background model,Object detection,hypothesis on degradation modification
更新于2025-09-09 09:28:46
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[IEEE 2018 International Seminar on Application for Technology of Information and Communication (iSemantic) - Semarang, Indonesia (2018.9.21-2018.9.22)] 2018 International Seminar on Application for Technology of Information and Communication - Improved Edge Detection Based on Adaptive Gaussian Smoothing in X-Ray Image
摘要： Currently technological developments are needed in all aspects of human life. It also covers the provision of data or information because it is related to someone's life. Data or information that provided in image formats is developed in health field of a human's life because it contains a lot of information about patient health that can’t be described by text or audio format. Currently due to the human body is susceptible to radiation rays then as long as the patient is detected by x-ray it will be subjected to a process of radiation exposure so that the x-ray image results in a decrease (degradation) of quality. There are several operations used in image processing to solve that problem. One of them is an edge detection. Due to the current edge detection is still considered not perfect because there is still Gaussian noise. So in this paper proposed method to improve image quality from quantum noise disorder by improving the method of Sobel, so can help the medical world in detecting a disease.
关键词： quality degradation,Sobel method,Gaussian noise,radiation exposure,edge detection
更新于2025-09-09 09:28:46
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Conductivity of Iron-doped Strontium Titanate in the Quenched and Degraded States
摘要： The electrical behavior of iron-doped strontium titanate (Fe:SrTiO3) single crystals equilibrated at 900 °C and quenched below 400 °C at various oxygen partial pressures ( ) was investigated via impedance spectroscopy and compared to defect chemistry models. Fe:SrTiO3 annealed and quenched between and Pa exhibits a conduction activation energy (EA) around 0.6 eV, consistent with ionic conduction of oxygen vacancies. However, sudden changes in EA are found to either side of this range; a transition from 0.6 to 1 eV is found in more oxidizing conditions, while a sudden transition to 1.1 and then 0.23 eV is found in reducing .These transitions, not described by the widely used canonical model, are consistent with predictions of transitions from ionic to electronic conductivity, based on first principles point defect chemistry simulations. These models demonstrate that activation energies in mixed conductors may not correlate to specific conduction mechanisms, but are determined by the cumulative response of all operative conduction processes and are very sensitive to impurities. A comparison to electrically degraded Fe:SrTiO3 provides insight into the origins of the conductivity activation energies observed in those samples.
关键词： defect chemistry,Strontium titanate,conductivity,resistance degradation
更新于2025-09-09 09:28:46
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Stone/Coating Interaction and Durability of Si-Based Photocatalytic Nanocomposites Applied to Porous Lithotypes
摘要： The use of hybrid nanocoatings for the protection of natural stones has received increasing attention over the last years. However, the interaction of these materials with stones and, in particular, its modification resulting from the blending of nanoparticles and matrices, are yet little explored. In this work, the interaction of two nanocomposite coatings (based on alkylalkoxysilane matrices and TiO2 nanoparticles in water and 2-propanol) with two different porous stones is examined in detail by comparing their absorption behaviour and protection performance with those of the respective TiO2-free matrices. It is shown that the protective effectiveness of both matrices is not negatively affected by the presence of TiO2, as the desired water barrier effect is retained, while a significant photocatalytic activity is achieved. The addition of titania leads to a partial aggregation of the water-based matrix and accordingly reduces the product penetration into stones. On the positive side, a chemical interaction between titania and this matrix is observed, probably resulting in a greater stability of nanoparticles inside the protective coating. Moreover, although an effect of TiO2 on the chemical stability of matrices is observed upon UV light exposure, the protective performance of coatings is substantially maintained after ageing, while the interaction between matrices and nanoparticles results in a good retention of the latter upon in-lab simulated rain wash-out.
关键词： UV ageing,stone protection,water-repellency,photo-oxidative degradation,durability,artificial rain,photocatalysis,TiO2 nanoparticles,alkylalkoxysilane
更新于2025-09-09 09:28:46
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Fabrication of flexible MIL-100(Fe) supported SiO2 nanofibrous membrane for visible light photocatalysis
摘要： Core/shell structured SiO2/MIL-100(Fe) fibrous membrane was prepared for photocatalytic degradation of dyes. The metal organic framework shells of MIL-100(Fe) were decorated on electrospun SiO2 nanofiber surface through layer-by-layer assembly. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy tests confirmed the successful synthesis of the MIL-100(Fe) nanoparticles. The formed SiO2/MIL-100(Fe) catalysts exhibited high catalytic activity towards degradation of Rhodamine B under visible light irradiation. The photocatalytic activity remained above 80% within 90 min illumination after three cycles. Due to the easy preparation and high photocatalytic performance, as well as convenient collection for reuse, the obtained SiO2/MIL-100(Fe) membranes are promising catalysts for practical application.
关键词： Layer-by-layer assembly,Visible light,SiO2/MIL-100(Fe),Dye degradation,Photocatalysis
更新于2025-09-09 09:28:46
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Facile synthesis of ZnBi2O4-graphite composites as highly active visible-light photocatalyst for the mineralization of rhodamine B
摘要： Novel highly active visible-light photocatalysts in the form of zinc bismuth oxide (ZnBi2O4) and graphite hybrid composites were prepared by coupling via a co-precipitation method followed by calcination at 450 oC. The as-prepared ZnBi2O4-graphite hybrid composites were tested for the degradation of rhodamine B (RhB) solutions under visible-light irradiation. The existence of strong electronic coupling between the two components within the ZnBi2O4-graphite heterostructure suppressed the photogenerated recombination of electrons and holes to a remarkable extent. The prepared composite exhibited excellent photocatalytic activity, leading to more than 93% of RhB degradation at an initial concentration of 50 mg·L?1 with 1.0 g catalyst per liter in 150 min. The excellent visible-light photocatalytic mineralization of ZnBi2O4-1.0graphite in comparison with pristine ZnBi2O4 could be attributed to synergetic effects, charge transfer between ZnBi2O4 and graphite, and the separation efficiency of the photogenerated electrons and holes. The photo-induced h+ and the superoxide anion were the major active species responsible for the photodegradation process. The results demonstrate the feasibility of ZnBi2O4-1.0graphite as a potential heterogeneous photocatalyst for environmental remediation.
关键词： ZnBi2O4,Mineralization,Degradation,Graphite,Photocatalyst
更新于2025-09-09 09:28:46
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Rational Design of Graphic Carbon Nitride Copolymers by Molecular Doping for Visible-Light-Driven Degradation of Aqueous Sulfamethazine and Hydrogen Evolution
摘要： Carbon nitride is a promising metal-free visible light driven photocatalyst and sustainable material for address contaminant pollution and water splitting. However, the insufficient visible light absorption and fast charge recombination of carbon nitride have limited its practical application. Herein, the self-assembly carbon nitride (denoted as TCN) by molecular doping copolymerization of urea and 2-thiobarbitucid acid (TA) was prepared. XPS and elemental analytical results indicated that TA was doped in the framework of carbon nitride successfully. The self-assembly copolymerization would result in the change of morphology, intrinsic electron and band structure of carbon nitride. Theoretical calculations and experiments confirm that the band gap of TCN could be adjusted by changing the amount of 2-thiobarbitucid acid. Moreover, the efficiency of charge carrier transfer and separation was greatly enhanced. As a result, the optimized photocatalyst TCN-0.03 exhibited superior activity with a high reaction rate of 0.058 min-1 for the degradation of sulfamethazine under visible light irradiation, which is 4.2 times higher than that of urea based carbon nitride (U-CN). As a multifunctional photocatalyst, TCN-0.03 showed enhanced activity for hydrogen production (55 μmol h-1), which was 11 times higher than U-CN. The apparent quantum efficiency reached to 4.8% at 420 nm. A possible mechanism was proposed to explain the photocatalytic reaction process. This work provides insight into the rational design of modified carbon nitride by other organic monomers copolymerization to enhance the photocatalytic activity.
关键词： Photocatalytic degradation,Photocatalytic hydrogen evolution,Carbon nitride,Charge carriers transfer,Molecular doping copolymerization
更新于2025-09-09 09:28:46