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Dynamics of an impurity ion transport in oil-paper insulation under various electric fields

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high Voltage 2024年第1期9卷 66-80页

作者： Yuanyang Ren Yang Wang Qiankai Zhang Jiayu Xiong Wen Cao Zepeng Lv Kai Wu State key laboratory of Electrical Insulation and power Equipment Xi'an Jiaotong UniversityXi'anChina School of electronics and Information Xi'an Polytechnic UniversityXi'anChina State Grid Sichuan Electric power Research Institute ChengduChina

The ionic transport process is an important counterpart to charge transport in oil-paper insulation,and it significantly impacts oil flow electrification at the oil-paper *** this,the dynamics of this phenomenon and the underlying mechanisms remain unclear,particularly at the molecular *** understand this fundamental aspect,we conduct Molecular Dynamics study on the transport behaviour of an impurity ion in different oil-paper insulation models under various external electric *** influence factors,such as external electric fields,temperatures,and local structural characteristics,are investigated in relation to the corresponding ionic mobility in different polymer *** to the simulations,ionic mobility and its response to electric fields are higher in weaker electrostatic *** a result,mineral oil exhibits the highest ionic mobility and the most substantial enhancement of ionic mobility by external electric fields,followed by vegetable oil,oil-paper blends,and insulating *** significant deviation in ionic mobility between oil and paper leads to the formation of an electric double layer near the oil-paper *** underlying physical mechanisms of different ionic mobility and its response to the electric field in different polymer models could be explained by the different polymer structural influences in terms of interaction energy and coordination numbers in a static manner,as well as by the interactions between the impurity ion and its surrounding atoms in terms of lifetime correlation functions and velocity autocorrelation functions in a dynamic *** addition,the influence of temperature on ionic mobility in mineral and vegetable oil is examined,and their activation energies are *** in the fundamental understanding of the dynamics of the ion transport process in oil-paper insulation is vital to improving their insulating properties for oil-impregnated power transformers.

关键词： insulation transport fields

power-efficient programmable integrated multiport photonic interferometer in CMOS-compatible silicon nitride

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Photonics Research 2024年第3期12卷 I0011-I0020页

作者： SHUQING LIN YANFENG ZHANG ZHAOYANG WU SHIHAO ZENG QING GAO JIAQI LI XIAOQUN YU SIYUAN YU State key laboratory of Optoelectronic Materials and Technologies School of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou 510275China Hefei national laboratory Hefei 230088China

Silicon nitride(SiNx)is an appealing waveguide material choice for large-scale,high-performance photonic integrated circuits(PICs)due to its low optical ***,SiNx PICs require high electric power to realize optical reconfiguration via the weak thermo-optic effect,which limits their scalability in terms of device density and chip power *** report a 6-mode programmable interferometer PIC operating at the wavelength of 1550 nm on a CMOS-compatible low-temperature inductance coupled plasma chemical vapor deposition(ICP-CVD)silicon nitride *** employing suspended thermo-optic phase shifters,the PIC achieves 2×improvement in compactness and 10×enhancement in power efficiency compared to conventional *** 6-dimensional linear transformations are demonstrated including cyclic transformations and arbitrary unitary *** work demonstrates the feasibility of fabricating power-efficient large-scale reconfigurable PICs on the low-temperature ICP-CVD silicon nitride platform.

关键词： unitary arbitrary figuration

Study on the influence of mechanism dispersion on transient recovery voltage distribution of modular DC vacuum circuit breakers

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high Voltage 2024年第2期9卷 346-355页

作者： Chongyang Huang Yongshuai Yin Shuxin Liu Hanwen Du Zengyu Shan Yundong Cao Shurui Yang key laboratory of Special Electric Machines and high Voltage Apparatus in the Ministry of Education Shenyang University of TechnologyShenyangChina Shenyang power Supply Company of State Grid Liaoning Electric power Co. LtdShenyangChina Chifeng power Supply Company of State Grid Mongolia Electric power Co. LtdChifengChina

A simulation analysis and an experiment are carried out to investigate how the gap difference between the breaks of a direct current vacuum circuit breakers with multi-breaks(MB-DC VCB)caused by the mechanism dispersion of the breaker influences the distribution of TRV among the *** interruption model of MB-DC VCB,combining the continuous transition model,is established to analyse the rising rate of transient recovery voltage and the dielectric strength recovery speed of the breaks for MB-DC VCB under different gap difference *** on the experimental platform of dual break DC vacuum circuit breaker breaking,the correctness of the simulation model is verified on a DC VCB with the double-breaks interruption experimental ***,a model is applied to the non-synchronous interruption simulation of a DC VCB with *** relationship between the TRVs of the breaks under different gap difference conditions is analysed using the comparative analysis method,obtaining the maximum gap difference at the moment of breaking *** results of this study show that large-gap breaks have a higher TRV than small-gap breaks(the fracture of the action delay module),with double fractures reaching 1.4 times and triple fractures reaching a maximum of 1.52 times;the ability of small-gap breaks to withstand TRV is weak,giving rise to re-breakdown or even interruption failure;as the number of fractures increases,the maximum gap difference also *** the synchronous interruption ability of the MB-DC VCB is conducive to improving the interruption performance and interruption success rate of this type of a circuit breaker.

关键词： TRV transient distribution

Fast measurement and prediction method for electromagnetic susceptibility of receiver

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Journal of Systems Engineering and electronics 2024年第2期35卷 275-285页

作者： CHEN Yan LU Zhonghao LIU Yunxia State key laboratory of Complex Electromagnetic Environment Effects on electronics and Information System College of Electronic Science and TechnologyNational University of Defense TechnologyChangsha 410073China State key laboratory of Astronautic Dynamics Xi’an 710043China

Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequency is proposed to improve the traditional two-tone ***,two signal generators are used to generate signals at the radio frequency(RF)by frequency scanning,and then a rapid measurement at the intermediate frequency(IF)output port is carried out to obtain a huge amount of sample data for the subsequent ***,the IF output response data are modeled and analyzed to construct the linear and nonlinear response constraint equations in the frequency domain and prediction models in the power domain,which provide the theoretical criteria for interpreting and predicting electromagnetic susceptibility(EMS)of the *** experiment performed on a radar receiver confirms the reliability of the method proposed in this *** shows that the interference of each harmonic frequency and each order to the receiver can be identified and predicted with the sensitivity *** on this,fast and comprehensive evaluation and prediction of the receiver’s EMS in complex environment can be efficiently realized.

关键词： electromagnetic susceptibility(EMS) receiver dualchannel multi-frequency nonlinear response frequency domain power domain

Experimental study on effects of gas flow rate on soot characteristics in diffusion flames coupled with plasma

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Science China(Technological Sciences) 2024年第2期67卷 475-485页

作者： QI DanDan CHEN MingXiao TU Xin LIU Dong MIIT key laboratory of Thermal Control of Electronic Equipment School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China Advanced Combustion laboratory School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China Department of Electrical Engineering and electronics University of LiverpoolLiverpool L693GJUK

This study examined the evolution of morphology and nanostructure of soot particles from the plasma-flame interaction for various gas flow *** current study used both optical diagnostic and sampling methods to explore the soot production and combustion *** particles were characterized at the same positions downstream from the flame zone by thermophoretic sampling and transmission electron ***,X-ray diffraction analysis,and thermogravimetric analysis were performed to study the nanostructure and oxidation reactivity of soot.A reduction in soot concentration was found with the plasma addition,which illustrated an inhibition effect of plasma on soot *** increased gas flow rate promoted soot concentration since a growing number of carbons participated in the combustion *** on the gas flow rate(carbon content)variation and plasma activation,either liquid-like soot material with irregularly shaped protrusions or chain-like structure,or a mixture of both,were generated from the diffusion *** soot produced by plasma-flame interaction also demonstrated a high correlation between nanostructure and *** soot from lower carbon content with plasma activation had a shorter fringe length and larger fringe tortuosity related to higher oxidation *** the contrary,soot from the highest carbon content without plasma-flame interaction exhibited prevalent fullerene-like nanostructures with evident large or small shells and also had a higher carbonization degree resulting in lower oxidation reactivity.

关键词： soot characteristics gas flow rate plasma diffusion flames

Current-collapse suppression and leakage-current decrease in AlGaN/GaN HEMT by sputter-TaN gate-dielectric layer

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Journal of Semiconductors 2024年第7期45卷 70-75页

作者： Bosen Liu Guohao Yu Huimin Jia Jingyuan Zhu Jiaan Zhou Yu Li Bingliang Zhang Zhongkai Du Bohan Guo Lu Wang Qizhi Huang Leifeng Jiang Zhongming Zeng Zhipeng Wei Baoshun Zhang State key laboratory of high-power Semiconductor Laser School of PhysicsChangchun University of Science and TechnologyChangchun 130022China Nanofabrication facility Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China Suzhou powerhouse electronics Technology Co. Ltd.Suzhou 215123China

In this paper, we explore the electrical characteristics of high-electron-mobility transistors(HEMTs) using a TaN/AlGaN/GaN metal insulating semiconductor(MIS) structure. The high-resistance tantalum nitride(TaN) film prepared by magnetron sputtering as the gate dielectric layer of the device achieved an effective reduction of electronic states at the TaN/AlGaN interface, and reducing the gate leakage current of the MIS HEMT, its performance was enhanced. The HEMT exhibited a low gate leakage current of 2.15 × 10^(-7) mA/mm and a breakdown voltage of 1180 V. Furthermore, the MIS HEMT displayed exceptional operational stability during dynamic tests, with dynamic resistance remaining only 1.39 times even under 400 V stress.

关键词： AlGaN/GaN MIS HEMTs gate dielectric layer depletion-mode gate reliability I_(on)/I_(off)ratio

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Revealing the Role of Defect in 3D Graphene-Based Photocatalytic Composite for Efficient Elimination of Antibiotic and Heavy Metal Combined Pollution

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Energy & Environmental Materials 2024年第3期7卷 164-174页

作者： Xin Wang Jingzhe Zhang Hui Wang Mengjun Liang Qiang Wang Fuming Chen Research Institute of Frontier Science Southwest Jiaotong UniversityChengdu 610031China Guangdong Provincial key laboratory of Quantum Engineering and Quantum Materials School of Electronics and Information EngineeringSouth China Normal UniversityFoshan 528225China School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Hubei key laboratory for high-Efficiency Utilization of Solar Energy and Operation Control of Energy Storage System Hubei University of TechnologyWuhan 430068China MOE key laboratory of Thermo-Fluid Science and Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

Defect engineering can give birth to novel properties for adsorption and photocatalysis in the control of antibiotics and heavy metal combined pollution with photocatalytic ***,the role of defects and the process mechanism are complicated and ***,TiO_(2)/CN/3DC was fabricated and defects were introduced into the tripartite structure with separate O_(2)plasma treatment for the single *** find that defect engineering can improve the photocatalytic activity,attributing to the increase of the contribution from h^(+)and *** contrast to TiO_(2)/CN/3DC with a photocatalytic tetracycline removal rate of 75.2%,the removal rate of TC with D-TiO_(2)/CN/3DC has increased to 88.5%.Moreover,the reactive sites of tetracycline can be increased by adsorbing on the defective *** defect construction on TiO_(2)shows the advantages in tetracycline degradation and Cu^(2+)adsorption,but also suffers significant inhibition for the tetracycline degradation in a tetracycline/Cu^(2+)combined *** contrast,the defect construction on graphene can achieve the cooperative removal of tetracycline and Cu^(2+).These findings can provide new insights into water treatment strategies with defect engineering.

关键词： 3D graphene Cu defect photocatalytic composite tetracycline

highly Sensitive Ammonia Gas Sensors at Room Temperature Based on the Catalytic Mechanism of N,C Coordinated Ni Single-Atom Active Center

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Nano-Micro Letters 2024年第12期16卷 515-531页

作者： Wenjing Quan Jia Shi Min Zeng Wen Lv Xiyu Chen Chao Fan Yongwei Zhang Zhou Liu Xiaolu Huang Jianhua Yang Nantao Hu Tao Wang Zhi Yang national key laboratory of Advanced Micro and Nano Manufacture Technology Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Department of Micro/Nano electronics School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Shanghai key laboratory of Intelligent Sensing and Detection Technology School of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237People’s Republic of China

Significant challenges are posed by the limitations of gas sensing mechanisms for trace-level detection of ammonia(NH3).In this study,we propose to exploit single-atom catalytic activation and targeted adsorption properties to achieve highly sensitive and selective NH3 gas ***,Ni singleatom active sites based on N,C coordination(Ni-N-C)were interfacially confined on the surface of two-dimensional(2D)MXene nanosheets(Ni-N-C/Ti_(3)C_(2)Tx),and a fully flexible gas sensor(MNPE-Ni-N-C/Ti_(3)C_(2)Tx)was *** sensor demonstrates a remarkable response value to 5 ppm NH3(27.3%),excellent selectivity for NH3,and a low theoretical detection limit of 12.1 *** analysis by density functional calculation reveals that the Ni single-atom center with N,C coordination exhibits specific targeted adsorption properties for ***,its catalytic activation effect effectively reduces the Gibbs free energy of the sensing elemental reaction,while its electronic structure promotes the spill-over effect of reactive oxygen species at the gas-solid *** sensor has a dual-channel sensing mechanism of both chemical and electronic sensitization,which facilitates efficient electron transfer to the 2D MXene conductive network,resulting in the formation of the NH3 gas molecule sensing ***,the passivation of MXene edge defects by a conjugated hydrogen bond network enhances the long-term stability of MXene-based electrodes under high humidity *** work achieves highly sensitive room-temperature NH3 gas detection based on the catalytic mechanism of Ni single-atom active center with N,C coordination,which provides a novel gas sensing mechanism for room-temperature trace gas detection research.

关键词： Gas sensor Single atom Catalytic activation Targeted adsorption End-sealing passivation

Atomistic study on the microscopic mechanism of grain boundary embrittlement induced by small dense helium bubbles in iron

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Nuclear Science and Techniques 2024年第3期35卷 84-95页

作者： Lei Peng Yong-Jie Sun Jing-Yi Shi Yi-Fei Liu Shang-Ming Chen Liu-Liu Li State key laboratory of Particle Detection and electronics University of Science and Technology of ChinaHefei 230026China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230027China Science and Technology on Reactor System Design Technology laboratory Nuclear Power Institute of ChinaChengdu 610213China

The helium bubbles induced by 14 MeV neutron irradiation can cause intergranular fractures in reduced activation ferritic martensitic steel,which is a candidate structural material for fusion *** order to elucidate the susceptibility of different grain boundaries(GBs)to helium-induced embrittlement,the tensile fracture processes of 10 types of GBs with and without helium bubbles in body-centered cubic(bcc)iron at the relevant service temperature of 600 K were investigated via molecular dynamics *** results indicate that in the absence of helium bubbles,the GBs studied here can be classified into two distinct categories:brittle GBs and ductile *** atomic scale analysis shows that the plastic deformation of ductile GB at high temperatures originates from complex plastic deformation mechanisms,including the Bain/Burgers path phase transition and deformation twinning,in which the Bain path phase transition is the most dominant plastic deformation ***,the presence of helium bubbles severely inhibits the plastic deformation channels of the GBs,resulting in a significant decrease in elongation at *** bubble-decorated GBs,the ultimate tensile strength increases with the increase in the misorientation ***,the coherent twin boundary∑3{112}was found to maintain relatively high fracture strength and maximum failure strain under the influence of helium bubbles.

关键词： Helium bubble Grain boundary Embrittlement Reduced activation ferritic martensitic steel Molecular dynamics Bain path