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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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[IEEE 2018 Prognostics and System Health Management Conference (PHM-Chongqing) - Chongqing, China (2018.10.26-2018.10.28)] 2018 Prognostics and System Health Management Conference (PHM-Chongqing) - A Remaining Useful Life Prediction Method for T/R Module Based on Index Similarity
摘要： T/R module is an important part of large phased array radar antenna array, the remaining useful life (RUL) prediction is of great significance for equipment support personnel to master current health status and improve maintenance support ability. At first, the key indexes of multi-state degradation are extracted by association rule, by calculating the similarity of the key indexes and combining the RUL of similar samples, the RUL information corresponding to the key indexes is obtained. The RUL prediction results of T/R module are obtained according to the weight of different indexes. The practicability and effectiveness of the proposed method are verified by example analysis and comparison, which provide theoretical guidance for the RUL prediction of electronic equipment. The proposed method is of great significance for maintenance support personnel of the military equipment to plan the maintenance resources reasonably and improve the combat effectiveness of the equipment.
关键词： index,T/R module,association rule,multi-state degradation,remaining useful life prediction,entropy weight method
更新于2025-09-23 15:22:29
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Immobilization of Fe3O4/TiO2 nanocomposite thin layer on the glass tubes in a component parabolic collector for the treatment of DR23
摘要： Photocatalysis driven by the natural solar light has been proved to be a favorable approach for the degradation of hazardous organic pollutants in water and wastewater. The present work addressed the removal of Direct Red 23 by the solar/Fe3O4/TiO2/S2O8^2- process. The application of the component parabolic collector, which served as a solar light concentrator, could improve the photocatalytic removal efficiency in the presence of immobilized Fe3O4/TiO2 nanoparticles. In this paper, the synthesis of Fe3O4/TiO2 photocatalyst to treat wastewater under solar radiation has been reported. Accordingly, a component parabolic collector solar photoreactor was designed and constructed for wastewater treatment processes. The prepared Fe3O4/TiO2 nanocomposite was precipitated as a thin layer on the glass tubes of the solar photoreactor. The central composite experimental design was also used in order to optimize and model the CI Direct Red 23 decolorization process; then, the influence of operational parameters such as the contaminant concentration, S2O8^2- concentration, and the reaction time was investigated. Due to the solar/Fe3O4/TiO2/S2O8^2- process, 100% of Direct Red 23 could be removed in 90 min at the concentration of 15.16 mg L?1 and S2O8^2- concentration of 0.8 mM. The predicted response for the Direct Red 23 decolorization efficiency in the optimal condition was obtained to be 98.50%, which was in a good agreement with the experimental response (100%).
关键词： Photoreactor,Degradation,Optimization,Photocatalysis
更新于2025-09-23 15:22:29
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Heterogeneous degradation of organic contaminants in the photo-Fenton reaction employing pure cubic β-Fe2O3
摘要： Pure cubic β-Fe2O3 crystal, which can absorb visible light (< 650 nm) on account of the bandgap of 1.9 eV as a direct bandgap semiconductor, was employed as a low-cost and non-toxic catalyst for photo-Fenton reaction in this article. Diverse organic contaminants including rhodamine B (RhB), methyl orange (MO), alizarin red (AR) and phenol can be effectively degraded. In particular, the degradation of RhB were investigated detailedly. As such, hydroxyl radicals (%OH) were verified to act as considerable active species for the process by using terephthalic acid as an indicator. Degradation mechanism and intermediates of phenol in the photo-Fenton reaction was discovered by virtue of liquid chromatography-mass spectrometry (LCeMS). Notably, hydroxylation of phenol generated some intermediates, which are converted into H2O and CO2 eventually.
关键词： Photo-Fenton,H2O2,β-Fe2O3,Degradation,Hydroxyl radicals
更新于2025-09-23 15:22:29
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Photocatalytic toluene degradation over Bi-decorated TiO2: Promoted O2 supply to catalyst’s surface by metallic Bi
摘要： In the photocatalytic volatile organic compounds (VOCs) degradation, the accumulation of intermediate products on the surface of catalysts could cause a decrease in activity through retarding reactant (e.g. O2) supply to surface active sites. Herein, Bi decorated TiO2 photocatalysts (Bi/TiO2) for photocatalytic toluene degradation were prepared and systematically studied. It is found that metallic Bi modification improves the ability of photocatalysts to capture O2. As a result, the activities of the Bi/TiO2 photocatalysts are obviously higher than that of the TiO2 for photocatalytic toluene degradation, and the productions of photogenerated reactive oxygen species (O2? and H2O2) over the Bi/TiO2 photocatalysts are almost equal to that over the TiO2 despite the fact that the separation efficiency of photoinduced charge carriers is decreased after the addition of Bi. Adsorbed benzaldehyde is the main surface intermediate on the surface of the Bi/TiO2 photocatalysts, whereas plenty of more readily oxidized aliphatic carboxylate species was monitored on the surface of the TiO2, which can be attributed to insufficient O2 supply to the TiO2 surface. This further indicates the positive role of the promoted O2 supply by Bi in the photocatalytic toluene degradation. The present work offers a new window for addressing the catalyst deactivation in the photocatalytic VOCs degradation.
关键词： The uptake of O2,Intermediate products,Metallic Bi,Photocatalytic VOCs degradation
更新于2025-09-23 15:22:29
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Effect of short-circuit stress on the degradation of the SiO2 dielectric in SiC power MOSFETs
摘要： This paper presents the impact of a short-circuit event on the gate reliability in planar SiC MOSFETs, which becomes more critical with increased junction temperature and higher bias voltages. The electrical waveforms indicate that a gate degradation mechanism takes place, showing a large gate leakage current that increases as the gate degrades more and more. A failure analysis has been performed on the degraded SiC MOSFET and then compared to the structure of a new device to identify possible defects/abnormalities. A Focused-Ion Beam cut is performed showing a number of differences in comparison to the new device: (i) cracks between the poly-silicon gate and aluminium source, (ii) metal particles near the source contact, and (iii) alterations in the top surface of the aluminium source. The defects have been correlated with the increase in gate-leakage current and drain-leakage current.
关键词： Focused-Ion Beam,Short circuit,Gate-oxide breakdown,Gate oxide,Degradation,Defects,Reliability,SiC MOSFET,Failure analysis,SEM
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Chemical Analysis of Solid Insulation Degradation using the AFM-IR Technique
摘要： To enable the continued development of power transmission cabling, an understanding of the processes which result in their failures is essential. In order to do so, powerful analysis techniques are required. However, those which consider chemical degradation are lagging behind those for visible degradation. This paper presents the Atomic Force Microscopy - Infrared Spectroscopy (AFM-IR) chemical analysis technique, which can provide surface chemical analysis with resolution of ~50 nm across the infrared spectrum. Two cases are considered: interfacial tracking between epoxy and silicone rubber, and the degraded region formed in front of a needle tip in the electrical tree initiation process. The results obtained using AFM-IR are compared to the outcomes from other techniques. It is found that AFM-IR offers a unique and powerful insight into visible and non-visible degradation of solid dielectrics.
关键词： AFM-IR,epoxy,chemical analysis,interfacial tracking,Electrical treeing,degradation
更新于2025-09-23 15:22:29
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Activated Hydrotalcites Obtained by Coprecipitation as Photocatalysts for the Degradation of 2,4,6-Trichlorophenol
摘要： A gallery of hydrotalcite-type mesoporous materials with different Mg/Al molar ratios were synthesized by the coprecipitation method. The materials were activated by heat treatment to test their activity in the photodegradation of 2,4,6-trichlorophenol under UV light irradiation. The physicochemical properties of the different synthesized and activated materials were determined using XRD, physical adsorption/desorption of N2, FTIR, SEM, DTA, and TGA. Their banned band energy was determined by UV-Vis to identify their potential to be used as a semiconductor in catalytic photodegradation processes. The results of photodegradation tests of 2,4,6-trichlorophenol showed that hydrotalcites have a high degradation capacity, up to 100% for the catalyst of Mg/Al ratio = 2, with a high mineralization capacity of 80%. The degradation capacity of most of the catalysts tested is mainly due to the presence of holes and the formation of superoxide free radicals, which are the determining species within the degradation mechanism.
关键词： 2,hydrotalcites,4,degradation,photocatalysts,6-trichlorophenol,UV light,coprecipitation
更新于2025-09-23 15:22:29
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Synthesis and Characterization of ZnO-ZrO <sub/>2</sub> Nanocomposites for Photocatalytic Degradation and Mineralization of Phenol
摘要： ZnO-ZrO2 nanocomposites using zinc (II) acetylacetonate and different ZnO contents (13, 25, 50, and 75% mol) were synthesized through sol-gel method. The synthesis process was strongly related to nanocomposite properties especially on their structural composition. The obtained ZnO-ZrO2 nanomaterials presented tetragonal crystalline structure for zirconia whereas hexagonal one was formed in ZnO. Raman spectroscopy and XRD patterns confirmed the formation of tetragonal zirconia whereas inhibition of monoclinic structure was observed. Addition of ZnO affected the pore size distribution of the composite, and the measured specific surface areas were from 10 m2/g (for pure ZnO) to 46 m2/g (pristine ZrO2). Eg values of ZrO2 were modified by ZnO addition, since calculated values using Kubelka-Munk's function varied from 4.73 to 3.76 eV. The morphology and size of the nanomaterials investigated by electron microscopy showed formation of nanorods for ZnO with sizes ranging from 50 nm to 300 nm while zirconia was formed by smaller particles (less than 50 nm). The main advantage of using the nanocomposite for photocatalytic degradation of phenol was the mineralization degree, since 75ZnO-ZrO2 nanocomposite surpassed mineralization reached by pure ZnO and also inhibited formation of undesirable intermediates.
关键词： sol-gel method,UV-A irradiation,phenol mineralization,photocatalytic degradation,ZnO-ZrO2 nanocomposites
更新于2025-09-23 15:22:29
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Microwave Hydrothermal Synthesis of In <sub/>2</sub> O <sub/>3</sub> -ZnO Nanocomposites and Their Enhanced Photoelectrochemical Properties
摘要： Indium oxide (In2O3) doped zinc oxide (ZnO) nanocomposites were successfully synthesized through a facile microwave hydrothermal method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption isotherms (BET) and UV-Vis diffuse reflectance spectroscopy. The morphology of In2O3-ZnO composites was observed to be like flowers, and the diameter of particles constituting the porous petal was about 30 nm. The photoelectrocatalytic test results showed that the photoelectrocatalytic methylene blue (MB) degradation efficiency using In2O3-ZnO nanocomposites as photocatalysts under visible light irradiation and a certain voltage could reached above 95.3% after 60 min, much higher than that of In2O3 particles and ZnO particles. The enhanced photoelectrocatalytic activity was attributed to the doping of In2O3 and applied voltage, which beneficially reduced the recombination of electrons and holes in the photoelectrocatalytic process, therefore, it promoted the production of active species (?OH and ?O2-).
关键词： photoelectrochemical properties,visible light irradiation,methylene blue degradation,In2O3-ZnO nanocomposites,microwave hydrothermal synthesis
更新于2025-09-23 15:22:29
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Assessing the Condition of Gas Turbine Rotor Blades with the Optoelectronic and Thermographic Methods
摘要： Gas turbines and their blades in particular might be damaged in the course of the aviation turbojet engine operation process. The degradation process of the blade microstructure is most evident from the change in the colour of its surface. This is assessed using the optoelectronic method. The article presents the concept of non-destructive methods, which are used to assess the degree of degradation of the alloy of a gas turbine blade. The proposed optoelectronic method is the basic method for the preliminary determination of color changes in the surface. Appropriate videoscopes or video-analyzers, capable of recording a test object in various electromagnetic wave ranges (infrared radiation, visible range), are used for this purpose. These preliminary results of the diagnosis make it possible to infer further studies of the blade. For accurate investigation of the state of the alloy microstructure, a non-destructive thermographic method (xenon flash pulsed thermography) was used. The results of studies of the degradation of the microstructure with the use of non-destructive methods were verified through the use of metallographic investigations. Appropriate metallographic specimens were created in order to recognize phase γ' degradation (i.e., the phase strengthening the blade alloy). The results of the presented research allowed for an in-depth assessment of the degree of microstructure degradation of operated blades.
关键词： impulse thermography,Turbine blade,digital image,microstructure degradation
更新于2025-09-23 15:22:29