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New insights on thermal ageing of electrical insulating oils as revealed from photoluminescence and absorption spectroscopy

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High Voltage 2024年第5期9卷 1033-1045页

作者： Hesham S.Karaman Eman G.Atiya Diaa-Eldin A.Mansour Mohsen Ghali Z.M.S.Elbarbary Manal M.Emara Department of Electrical Engineering Faculty of Engineering at ShoubraBenha UniversityCairoEgypt Department of Electrical Power and Machines Engineering Faculty of EngineeringTanta UniversityTantaEgypt Department of Electrical Power Engineering Faculty of EngineeringEgypt-Japan University of Science and Technology(E-JUST)New Borg El-Arab CityAlexandriaEgypt Department of Energy Materials Institute of Basic and Applied ScienceEgypt-Japan University of Science and Technology(E-JUST)New Borg El-Arab CityAlexandriaEgypt Department of Physics Faculty of ScienceKafrelsheikh UniversityKafrelsheikhEgypt Department of Electrical Engineering College of EngineeringKing Khalid UniversityAbhaSaudi Arabia Center for Engineering and Technology Innovations King Khalid UniversityAbhaSaudi Arabia Department of Electrical Engineering Faculty of EngineeringKafrelsheikh UniversityKafrelsheikhEgypt

Recently,significant efforts have been exerted to replace mineral oil with environmentally friendly oils due to safety and environmental ***,there is a need to clarify the physical mechanisms behind the ageing impact of these *** authors use advanced optical spectroscopy techniques in correlation with dielectric measurements to understand the ageing processes in environmentally friendly oils as well as mineral ***,different samples of environmentally friendly oils and mineral oil were utilised to investigate the ageing *** samples were subjected to different ageing periods using a thermal accelerated ageing ***,the severity of the produced byproducts due to the oil degradation is examined based on several measured properties representing macroscopic and microscopic *** macroscopic category was evaluated through dielectric properties,including breakdown voltage,dielectric permittivity,and dissipation *** microscopic category,on the other hand,was assessed using techniques such as ultraviolet-visible absorption spectroscopy and photoluminescence *** techniques enabled a deep understanding of the molecular-level changes occurring in the oil under ageing conditions,thereby getting new insights into oil ageing *** is worth mentioning that natural ester oil demonstrated the most favourable performance across various properties under ageing conditions.

关键词： absorption thermal spectroscopy

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Preparation and dielectric properties of Al2O3-based ceramic composites with Sm2O3 and ZrO2 additives for terahertz applications

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Ceramics International 2025年第13期51卷 17744-17754页

作者： Purlu, Kagan Murat Dalgac, Sekip Isik, Elif Yildiz, Betul Kafkaslioglu Elmabruk, Kholoud Sivas University of Science and Technology Faculty of Engineering and Natural Sciences Electrical and Electronics Engineering Department Sivas Turkey Sivas University of Science and Technology Faculty of Engineering and Natural Sciences Metallurgical and Materials Engineering Department Sivas Turkey

As Terahertz (THz) electromagnetic waves become significant for industrial applications, the choice and electrical characterization of materials play important roles in improving system efficiency. Due to their unique properties, ceramics have recently become increasingly explored for THz applications. To this end, the samples of Al2O3-based ceramic composites with Sm2O3 and ZrO2 additives are prepared. The prepared ceramic composites are characterized utilizing THz time-domain spectroscopy (THz-TDS), a powerful analytical technique employing THz radiation. First, the impact of sintering temperature on the dielectric properties of the pure Al2O3 is examined. Thus, the sintering temperature is set at 1550 °C to fabricate the other composites. Moreover, the impact of ZrO2, Sm2O3 and ZrO2-Sm2O3 additives on the dielectric properties of Al2O3-based ceramic composites is examined. In this context, the refractive index, permittivity, absorption coefficient and loss tangent of Al2O3-based ceramic composites are studied. Accordingly, it is observed that the dielectric constant and refractive indices of composites containing ZrO2, Sm2O3 and ZrO2-Sm2O3 additives increase compared to the pure-Al2O3. Moreover, while the loss tangent decreases with Sm2O3 additives, ZrO2, and ZrO2-Sm2O3 additives cause a rise in the loss tangent. The presented results enable us not only to choose the proper composite but also to enhance the dielectric properties of Al2O3-based ceramics. Consequently, they pave the way for the use of Al2O3-based ceramic composites with Sm2O3 and ZrO2 additives in a wide range of THz applications. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Sintering

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Bifunctional electrolyte addition for longer life and higher capacity of aqueous zinc-ion hybrid supercapacitors

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Rare Metals 2024年第10期43卷 5060-5069页

作者： Fan Zhang Si-Qi Li Li-Nan Xia Chao Yang Lei Li Kai-Ming Wang Chen-Liang Xu Yuan-Yuan Feng Bin Zhao Fei Shen Xiao-Gang Han Ling-Yun Zhu School of Electric Power Civil Engineering and ArchitectureShanxi UniversityTaiyuan 030006China State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi'an Jiaotong UniversityXi'an 710049China Department of Science Materials and Engineering National University of SingaporeSingapore 117576Singapore School of Materials Science and Engineering Anhui UniversityHefei230601China

Owing to uncontrolled and uneven electrodeposition and side reactions,Zn metal anodes inevitably suffer from issues such as dendrite growth,hydrogen evolution reactions,and surface *** paper proposes an efficient strategy to address these critical issues for realizing long-life and high-capacity aqueous zinc-ion hybrid supercapacitors(ZHSCs)by incorporating low-concentration(0.05 mol·L^(-1))redox RbI electrolyte ***,rubidium cations have the ability to influence the negative Zn electrode surface via an electrostatic shielding mechanism,effectively protecting the electrode and minimizing undesired side *** an aqueous solution,iodide anions actively solvate Zn^(2+)ions by stabilizing and modulating the solvation shell surrounding Zn^(2+).Moreover,the presence of iodide ions promotes the uniform deposition of Zn^(2+)species by selective adsorption onto the electrode *** synergistic effect of the electrostatic shielding and halogen ions enables the realization of aqueous symmetric Zn||Zn cells with a substantial cycle life of more than 2000 h Additionally,when applied to commercial activated carbon(AC),the proposed strategy facilitates the development of aqueous ZHSCs,exhibiting high specific capacitances(148.8 F·g^(-1)at 4 A·g^(-1))and ultra-long cycling stability.

关键词： Zn metal anode Zn dendrite Aqueous zincion hybrid supercapacitor Rubidium iodide Synergistic effects of anions and cations

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Superior efficiency and stability of YbO_(x)-enhanced perovskite solar cells

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science China materials 2024年第4期67卷 1356-1358页

作者： Qifeng Zhang Guozhong Cao Department of Electrical and Computer Engineering North Dakota State UniversityFargoND 58108-6050USA Department of Materials Science and Engineering University of WashingtonSeattleWA 98195-2120USA

Perovskite solar cells represent a revolutionary class of photovoltaic devices that have gained substantial attention for their exceptional performance and potential to provide an affordable and efficient solution for harnessing solar energy. These cells utilize perovskite-structured materials, typically hybrid organicinorganic lead halide compounds, as the light-absorbing layer.

关键词： energy perovskite stability

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Surface phase diagram of CsSnI3 from first-principles calculations

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Physical Review materials 2024年第9期8卷 093401页

作者： Kejia Li Chadawan Khamdang Mengen Wang Department of Electrical and Computer Engineering Materials Science and Engineering Program

CsSnI3 is widely studied as an environmentally friendly Pb-free perovskite material for optoelectronic device applications. To further improve material and device performance, it is important to understand the surface structures of CsSnI3. We generate surface structures with various stoichiometries, perform density functional theory calculations to create phase diagrams of the CsSnI3 (001), (110), and (100) surfaces, and determine the most stable surfaces under a wide range of Cs, Sn, and I chemical potentials. Under I-rich conditions, surfaces with Cs vacancies are stable, which lead to partially occupied surface states above the valence band maximum. Under I-poor conditions, we find the stoichiometric (100) surface to be stable under a wide region of the phase diagram, which does not have any surface states and can contribute to long charge-carrier lifetimes. Consequently, the I-poor (Sn-rich) conditions will be more beneficial to improve the device performance.

关键词： Electronic structure Surface reconstruction Surface states Perovskites Semiconductors Density functional theory

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Progress and prospects for all-perovskite tandem solar cells

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Journal of Energy Chemistry 2025年第4期103卷 90-96页

作者： Qingyang Wu Jingwei Zhu Dewei Zhao Department of Mechanical and Electrical Engineering Liaoning Provincial College of CommunicationsShenyang 110122LiaoningChina College of Materials Science and Engineering and Engineering Research Center of Alternative Energy Materials and Devices Ministry of EducationSichuan UniversityChengdu 610065SichuanChina

All-perovskite tandem solar cells(TSCs)consist of a wide-bandgap(WBG,1.75-1.8 eV)top subcell and a low-bandgap(LBG,1.2-1.3 eV)bottom subcell,exhibit superior power conversion efficiencies(PCEs)compared to single-junction perovskite solar cells(PSCs).In addition,the advantages of lowtemperature solution preparation and low manufactu ring cost make the all-perovskite tandem solar cells widely concerned,and are considered to be one of the most potential next-generation high-performance thin film photovoltaic *** this perspective,we briefly summarize the state-of-the-art advances in monolithic all-perovskite TSCs focusing on the following aspects:LBG perovskite bottom subcells,WBG perovskite top subcells,and interconnecting layers(ICLs).We then discuss the primary strategies to improve their performa nce and finally highlight the perspective regarding the achievement of efficient and stable all-perovskite tandems.

关键词： Wide-bandgap perovskite top subcell Low-bandgap perovskite bottom subcell Interconnecting layer All-perovskite tandem solar cell Progress Prospect

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PIN quantum-dot LEDs with enhanced efficiency and stability enabled by bulk-heterojunction hole transport layer

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Nano Research 2025年第2期18卷 751-759页

作者： Heng Zhang Zhe Wang Dawei Yang Bingsuo Zou Shuming Chen School of Resources Environments and MaterialsGuangxi UniversityNanning 530004China Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhen 518055China

Although quantum-dot light-emitting diodes(QLEDs)can exhibit high efficiency and long lifetime,the realization of QLEDs-based displays remains challenging due to their complex multilayer architectures and the use of unstable poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)hole injection layer(HIL).Here,we develop a novel trilayer p-type/intrinsic/n-type(PIN)QLED with only three functional layers:PTAA:TFB:F4-TCNQ(PTAA:poly[bis(4-phenyl)(2,4,6-trimethyl-phenyl)amine];TFB:poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine)];F4-TCNQ:2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane)bulk-heterojunction(BHJ)hole transport layer(HTL),quantum-dot emiting layer,and ZnMgO electron transport *** to well-matched energy level,increased hole transport path from PTAA to TFB,and improved hole density and enhanced hole mobility of the PTAA:TFB:F4-TCNQ BHJ HTL,the resultant trilayer PIN QLED exhibits a high external quantum efficiency(EQE)of 25.1%and an impressive peak brightness of 382,600 cd/m^(2),which are significantly higher than those of the control ***,the trilayer PIN QLED also shows a 1.94-fold longer operational lifetime than control QLED due to the improved device performance,reduced charge accumulation,and removal of unstable PEDOT:*** developed trilayer PIN QLED,with fewer functional layers and better stability,could promote the practical application of QLED in displays and solid-state lighting.

关键词： quantum dots light-emitting diodes trilayer hole transport layer p-type/intrinsic/n-type(PIN)

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Non-planar dielectrics derived thermal and electrostatic field inhomogeneity for boosted weather-adaptive energy harvesting

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National science Review 2023年第9期10卷 248-257页

作者： Yi Zhou Tianpeng Ding Yin Cheng Yi Huang Wu Wang Jianmin Yang Lin Xie Ghim Wei Ho Jiaqing He Shenzhen Key Laboratory of Thermoelectric Materials and Department of Physics Southern University of Science and Technology Department of Electrical and Computer Engineering National University of Singapore School of Electronic Science and Engineering State Key Laboratory of Electronic Thin Film and Integrated Devices University of Electronic Science and Technology of China Department of Materials Science and Engineering National University of Singapore Institute of Materials Research and Engineering Agency for ScienceTechnology and Research (A*STAR) GuangdongHong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices Southern University of Science and Technology

Weather-adaptive energy harvesting of omnipresent waste heat and rain droplets,though promising in the field of environmental energy sustainability,is still far from practice due to its low electrical output owing to diele ctric structure irrationality and *** we present atypical upcycling of ambient heat and raindrop energy via an all-in-one non-planar energy harvester,simultaneously increasing solar pyroelectricity and droplet-based triboelectricity by two-fold,in contrast to conventional *** delivered non-planar dielectric with high transmittance confines the solar irradiance onto a focal hotspot,offering transverse thermal field propagation towards boosted inhomogeneous polarization with a generated power density of 6.1 mW m-2at 0.2 ***,the enlarged lateral surface area of curved architecture promotes droplet spreading/separation,thus travelling the electrostatic field towards increased *** enhanced pyroelectric and triboelectric outputs,upgraded with advanced manufacturing,demonstrate applicability in adaptive sustainable energy harvesting on sunny,cloudy,night,and rainy *** findings highlight a facile yet efficient strategy,not only for weather-adaptive environmental energy recovery but also in providing key insights for spatial thermal/electrostatic field manipulation in thermo electrics and ferroelectrics.

关键词： non-planar dielectrics heat manipulation pyroelectrics weather-adaptive energy harvesting

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Texture development and surface reconstruction of BiVO_(4)photoanode via one-pot hydrothermal reaction for enhanced photoelectrochemical water splitting

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Journal of Advanced Ceramics 2025年第3期14卷 133-141页

作者： Sung Won Hwang Yoo Jae Jeong Runfa Tan Indhujasri Saravanan Hyun Soo Han Dong Hoe Kim In Sun Cho Department of Energy Systems Research Ajou UniversitySuwon 16499Republic of Korea Department of Material Science&Engineering Ajou UniversitySuwon 16499Republic of Korea Department of Mechanical Engineering Stanford UniversityStanford 94305USA Department of Material Science&Engineering Korea UniversitySeoul 02841Republic of Korea Materials Science and Engineering Program University of Colorado BoulderBoulder 80303USA

The simultaneous optimization of the bulk and surface characteristics of photoelectrodes is essential to maximize their photoelectrochemical(PEC)*** report a novel one-pot hydrothermal synthesis of textured and surface-reconstructed BiVO_(4)photoanodes(ts-BVO),achieving significant improvements in PEC water *** controlling precursor molarity and ethylene glycol(EG)addition,we developed a stepwise dual reaction(SDR)mechanism,which enables simultaneous bulk texture development and surface *** optimized CoBi/ts-BVO photoanode exhibited a photocurrent density of 4.3 mA∙cm^(−2)at 1.23 V *** hydrogen electrode(RHE)with a high Faradaic efficiency of 98%under one sun *** with nontextured BiVO_(4),the charge transport efficiency increased from 8%to 70%,whereas the surface charge transfer efficiency improved from 9%to 85%.These results underscore the critical role of both bulk and surface engineering in enhancing PEC *** findings offer a streamlined approach for improving the intrinsic properties of photoanodes in solar water splitting.

关键词： BiVO_(4) hydrothermal texture surface reconstruction ethylene glycol(EG) photoelectrochemical water splitting

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Multi-response Optimization of Process Parameters in Stretch Blow Molding of PET Plastic Bottles

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Journal of The Institution of Engineers (India): Series D 2024年 1-15页

作者： Merga, Henok Hailu Sinha, Devendra Kumar Getachew, Aklilu Workneh, Melese Rathee, Devender Singh Department of Mechanical Engineering School of Mechanical Chemical and Materials Engineering Center of Excellence Advanced Manufacturing Engineering Adama Science and Technology University Adama Ethiopia Department of Electronics Engineering School of Electrical Engineering and Computing Adama Science and Technology University Adama Ethiopia

Plastic waste in Polyethylene Terephthalate (PET) bottles is creating new challenges, which in today’s scenario is a major concern in every industry. The defect in PET bottles mainly occurs due to improper selection of levels of process parameters during the production process. Therefore, optimizations of process parameters are very important to minimize the defects produced due to improper stretch blow molding process parameter selections. The study is carried out on 2 L bottle since they have the highest demand and the highest defect rate in the PET bottling sector. The PET bottles have been developed from the preform at various blowing temperature, blowing speed and blowing angle on commercially available SBM setup. The design and plan of experiments have been done according to L9 orthogonal array of Taguchi method. The optimization of process parameters has been done through the hybrid Taguchi grey relational analysis optimization technique on four factors namely: blowing temperature, first blow angle, second blow angle and blowing speed. Each value of parameter was taken at three levels in combination. The testing of all samples such as tensile test, wall thickness measurement and hoop stretch ratio measurement have been carried out as per ASTM standards. The morphology of the samples has been carried out through scanning electron microscope. A maximum tensile strength of 65 MPa, minimum hoop stretch ratio of 5.45 and a maximum wall thickness 0.24 mm was found at varying process parameter combinations. It has been observed that among the process parameters: blowing temperature was the most significant factor for minimizing defects while second blow angle was the least significant parameter. It was found that optimized values of the process parameters yielded 15% reduction in defects on PET bottles. The present study is expected to contribute significantly for the industries working in this field for carrying out production at optimum levels of process parameter

关键词： Plastic bottles

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