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High Voltage 2024年第4期9卷 902-910页

作者： Giovanni Gardan Gian Carlo Montanari Dipartimento di Ingegneria Industriale Universita degli Studi di PadovaPadovaItaly center for advanced power systems Florida State UniversityTallahasseeFloridaUSA

With the increasing penetration of DC systems into the high voltage and medium voltage power industry,DC voltage is becoming common for distribution/transmission and to supply different typologies of *** allowable extent of AC ripple superimposed to DC,and its effect on insulation ageing,is a long-term discussed *** most harmful phenomenon causing extrinsic ageing acceleration and insulation system premature failure is partial discharges(PD);thus,the risk of incepting PD due to AC ripple could become a primary issue for electrical asset equipment *** this work,the impact of AC sinusoidal ripple on insulation system life and reliability is dealt with,considering both intrinsic and extrinsic ageing but focusing on the latter,that is,the PD *** are performed to assess how the jump voltage(due to AC ripple)and the DC component impact on PD activity in terms of amplitude and repetition *** the first time,the correlation between the magnitude of jump voltage associated with ripple and PD inception is established,shedding a light on the allowable ripple extent which does not impact significantly on ageing and premature insulation *** approach can provide straightforward tools for design specification and ageing inference of insulation systems.

关键词： impact insulation electrical

Analysis on carbon emission reduction intensity of fuel cell vehicles from a life-cycle perspective

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Frontiers in Energy 2024年第1期18卷 16-27页

作者： Ziyuan TENG Chao TAN Peiyuan LIU Minfang HAN Fuel Cell and Energy Storage center Department of Energy and Power EngineeringState Key Laboratory of Control and Simulation of Power Systems and Generation EquipmentTsinghua UniversityBeijing 100084China

The hydrogen fuel cell vehicle is rapidly developing in China for carbon reduction and *** paper evaluated the life-cycle cost and carbon emission of hydrogen energy via lots of field surveys,including hydrogen production and packing in chlor-alkali plants,transport by tube trailers,storage and refueling in hydrogen refueling stations(HRSs),and application for use in two different *** also conducted a comparative study for battery electric vehicles(BEVs)and internal combustion engine vehicles(ICEVs).The result indicates that hydrogen fuel cell vehicle(FCV)has the best environmental performance but the highest energy ***,a sufficient hydrogen supply can significantly reduce the carbon intensity and FCV energy cost of the current *** carbon emission for FCV application has the potential to decrease by 73.1%in City A and 43.8%in City *** only takes 11.0%–20.1%of the BEV emission and 8.2%–9.8%of the ICEV *** cost of FCV driving can be reduced by 39.1%in City *** improvement can be obtained with an economical and“greener”hydrogen production pathway.

关键词： hydrogen energy life-cycle assessment(LCA) fuel cell vehicle carbon emission energy cost

Multi-Objective Optimization of VBHF in Deep Drawing Based on the Improved QO-Jaya Algorithm

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 189-202页

作者： Xiangyu Jiang Zhaoxi Hong Yixiong Feng Jianrong Tan state Key Laboratory of Fluid power and Mechatronic systems Zhejiang UniversityHangzhou 310027China Key Laboratory of advanced Manufacturing Technology of Zhejiang Province Zhejiang UniversityHangzhou 310027China Ningbo Innovation center Zhejiang UniversityNingbo 315100China

Blank holder force(BHF)is a crucial parameter in deep drawing,having close relation with the forming quality of sheet ***,there are different BHFs maintaining the best forming effect in different stages of deep *** variable blank holder force(VBHF)varying with the drawing stage can overcome this problem at an *** optimization of VBHF is to determine the optimal BHF in every deep drawing *** this paper,a new heuristic optimization algorithm named Jaya is introduced to solve the optimization *** improved“Quasi-oppositional”strategy is added to Jaya algorithm for improving population ***,an innovated stop criterion is added for better ***,the quality evaluation criteria for wrinkling and tearing are ***,the Kriging models are developed to approximate and quantify the relation between VBHF and forming defects under random ***,the optimization models are established and solved by the improved QO-Jaya algorithm.A VBHF optimization example of component with complicated shape and thin wall is studied to prove the effectiveness of the improved Jaya *** optimization results are compared with that obtained by other algorithms based on the TOPSIS method.

关键词： Variable blank holder force Multi-objective optimization QO-Jaya algorithm Algorithm stop criterion

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High-capacity dilithium hydroquinone cathode material for lithium-ion batteries

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National Science Review 2024年第6期11卷 206-213页

作者： Yong Lu Haoqin Han Zhuo Yang Youxuan Ni Zhicheng Meng Qiu Zhang Hao Wu Weiwei Xie Zhenhua Yan Jun Chen Frontiers Science center for New Organic Matter Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) State Key Laboratory of Advanced Chemical Power SourcesCollege of ChemistryNankai University

Lithiated organic cathode materials show great promise for practical applications in lithium-ion batteries owing to their Li-reservoir characteristics. However, the reported lithiated organic cathode materials still suffer from strict synthesis conditions and low capacity. Here we report a thermal intermolecular rearrangement method without organic solvents to prepare dilithium hydroquinone（Li2Q）, which delivers a high capacity of 323 m Ah g-1with an average discharge voltage of 2.8 V. The reversible conversion between orthorhombic Li2Q and monoclinic benzoquinone during charge/discharge processes is revealed by in situ X-ray diffraction. Theoretical calculations show that the unique Li–O channels in Li2Q are beneficial for Li+ion diffusion. In situ ultraviolet-visible spectra demonstrate that the dissolution issue of Li2Q electrodes during charge/discharge processes can be handled by separator modification, resulting in enhanced cycling stability. This work sheds light on the synthesis and battery application of high-capacity lithiated organic cathode materials.

关键词： lithium-ion batteries cathode materials lithiated organic materials dilithium hydroquinone separator modification

Non-flammable long chain phosphate ester based electrolyte via competitive solventized structures for high-performance lithium metal batteries

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Journal of Energy Chemistry 2024年第10期97卷 156-165,I0004页

作者： Li Liao Zhiqiang Han Xuanjie Feng Pan Luo Jialin Song Yin Shen Xiaoshuang Luo Xinpeng Li Xuanzhong Wen Bo Yu Junchen Chen Bingshu Guo Mingshan Wang Yun Huang Hongmei Zhang Mengmeng Yin Jiangtao Liu Yuanhua Lin Xing Li School of New Energy and Materials Southwest Petroleum UniversityChengdu 610500SichuanChina state Key Laboratory of advanced Chemical power Sources Guizhou Meiling Power Sources Co.LtdZunyi 563003GuizhouChina Beijing advanced Innovation center for Materials Genome Engineering Center for Green InnovationSchool of Mathematics and PhysicsUniversity of Science and Technology BeijingBeijing 100083China

Safety remains a persistent challenge for high-energy-density lithium metal batteries(LMBs).The development of safe and non-flammable electrolytes is especially important in harsh conditions such as high ***,a flame-retardant,low-cost and thermally stable long chain phosphate ester based(tributyl phosphate,TBP)electrolyte is reported,which can effectively enhance the cycling stability of highly loaded high-nickel LMBs with high safety through co-solvation *** interfacial compatibility between TBP and electrode is effectively improved using a short-chain ether(glycol dimethyl ether,DME),and a specially competitive solvation structure is further constructed using lithium borate difluorooxalate(LiDFOB)to form the stable and inorganic-rich electrode *** from the presence of the cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)enriched with LiF and Li_(x)PO_(y)F_(z),the electrolyte demonstrates excellent cycling stability assembled using a 50μm lithium foil anode in combination with a high loading NMC811(15.4 mg cm^(-2))cathode,with 88%capacity retention after 120 ***,the electrolyte exhibits excellent high-temperature characteristics when used in a 1-Ah pouch cell(N/P=0.26),and higher thermal runaway temperature(238℃)in the ARC(accelerating rate calorimeter)demonstrating high *** novel electrolyte adopts long-chain phosphate as the main solvent for the first time,and would provide a new idea for the development of extremely high safety and high-temperature electrolytes.

关键词： Non-flammable electrolyte Long chain phosphate ester Solvation structure Lithium metal batteries Battery safety

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power Flow Model for Medium-voltage Distribution systems Considering Measurement and Structure Characteristics

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Journal of Modern power systems and Clean Energy 2024年第2期12卷 571-583页

作者： Zhengmei Lu Wei Yan Dezhi Huang Junjie Tang Ferdinanda Ponci Antonello Monti state Key Laboratory of power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqing 400044China state Grid Zhejiang Yiwu power Supply Company State Grid Zhejiang Electric Power CompanyYiwu 322001China Institute for Automation of Complex power systems of the E.ON Energy Research center at RWTH Aachen university Aachen52074Germany Digital Energy Fraunhofer FIT Aachen52072Germany IEEE

Medium-voltage distribution systems(MVDSs)mainly consist of a feeder head,lines,distribution transformers,and the equivalent load or power supply interfaced with the distribution *** information of such load or power supply can be measured via the three-wattmeter method(THM)and the two-wattmeter method(TWM).The measurements can be used to perform the control of the power supply and simulate the characteristics of the load,so the models of the load and the power supply need to consider the measurement *** research works on three-phase power flow(PF)just consider the measurement characteristics of ***,the PF equation of the bus measured via TWM is firstly *** on conventional measurements,an accurate and general model of the grounded and ungrounded slack bus is ***,the influence arising from the connection type and angle shift of distribution transformers on the admittance matrix is considered,and thus a general three-phase transformer model is summarized,which is applicable for all the transformers mentioned ***,Newton's method is adopted to solve the PF calculation,and the performance of the proposed PF model is demonstrated through designed tests.

关键词： Medium-voltage distribution system three-phase power flow calculation measurement characteristic slack bus modeling distribution transformer

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From tunnel boring machine to tunnel boring robot: perspectives on intelligent shield machine and its smart operation

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2024年第5期25卷 357-381页

作者： Yakun ZHANG Guofang GONG Huayong YANG Jianbin LI Liujie JING state Key Laboratory of Fluid power and Mechatronic systems Zhejiang UniversityHangzhou 310058China China Railway Engineering Equipment Group Co. Lid.Zhengzhou 450016China Maha Fluid power Research center Purdue UniversityWest LafayetteIN 47905USA

Advances in intelligent shield machines reflect an evolving trend from traditional tunnel boring machines(TBMs)to tunnel boring robots(TBRs).This shift aims to address the challenges encountered by the conventional shield machine industry arising from construction environment and manual *** study presents a systematic review of intelligent shield machine technology,with a particular emphasis on its smart ***,the definition,meaning,contents,and development modes of intelligent shield machines are *** development status of the intelligent shield machine and its smart operation are then *** analyzing the operation process of the shield machine,an autonomous operation framework considering both stand-alone and fleet levels is *** and recommendations are given for achieving autonomous *** study offers insights into the essence and developmental framework of intelligent shield machines to propel the advancement of this technology.

关键词： Intelligent shield machine Tunnel boring machine(TBM) Tunnel boring robot(TBR) Self-driving Autonomous control Shield machine

An active learning workflow for predicting hydrogen atom adsorption energies on binary oxides based on local electronic transfer features

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Green Energy & Environment 2024年第10期9卷 1489-1496页

作者： Wenhao Jing Zihao Jiao Mengmeng Song Ya Liu Liejin Guo International Research center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Department of Energy and power Engineering Shandong University of Technology

Machine learning combined with density functional theory（DFT） enables rapid exploration of catalyst descriptors space such as adsorption energy, facilitating rapid and effective catalyst screening. However, there is still a lack of models for predicting adsorption energies on oxides,due to the complexity of elemental species and the ambiguous coordination environment. This work proposes an active learning workflow（Le NN） founded on local electronic transfer features（e） and the principle of coordinate rotation invariance. By accurately characterizing the electron transfer to adsorption site atoms and their surrounding geometric structures, Le NN mitigates abrupt feature changes due to different element types and clarifies coordination environments. As a result, it enables the prediction of *H adsorption energy on binary oxide surfaces with a mean absolute error（MAE） below 0.18 e V. Moreover, we incorporate local coverage（θl） and leverage neutral network ensemble to establish an active learning workflow, attaining a prediction MAE below 0.2 e V for 5419 multi-*H adsorption structures. These findings validate the universality and capability of the proposed features in predicting *H adsorption energy on binary oxide surfaces.

关键词： Machine learning Adsorption energy Binary oxide Electron transfer Active learning

Effect of nucleating agents on the electrical properties of cross-linked polyethylene under tensile stress

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High Voltage 2024年第2期9卷 429-439页

作者： Yunqi Xing Jiahao Liu Jingang Su Junwei Zha Guochang Li Ze Guo Xiaozhen Zhao Mengjia Feng state Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjinChina Electric power Research Institute of state Grid Hebei Electric power Supply Co. Ltd.ShijiazhuangChina Beijing advanced Innovation center for Materials Genome Engineering School of Chemistry and Biological EngineeringUniversity of Science&Technology BeijingBeijingChina Institute of advanced Electrical Materials Qingdao University of Science and TechnologyQingdaoChina

During the operation of high-voltage cables,external stress and residual stress can affect the aggregated structure of insulating materials and lead to significant deterioration in their electrical *** investigate the evolution characteristics of the electrical properties of cross-linked polyethylene(XLPE)under mechanical stress,this paper ex-plains the relationship between the aggregated structure of XLPE and its electrical properties and proposes a method for improving insulation performance under me-chanical *** results show that metallocene polyethylene used as a nucleating agent can promote crystallisation through heterogeneous nucleation and increase Young's modulus by non-uniform nucleation,increasing crystallinity and reducing interplanar spacing,resulting in more complete crystal forms and reduced damage to the aggregated structure during the tensile *** nucleating agent modification,the XLPE crystallisation becomes more uniform,and interfacial adhesion forces *** weakened interface damage process between the amorphous and crystalline regions under tensile stress effectively inhibits the process of molecular chain polarisation turning and reduces trap *** modified XLPE crystal structure shows a tendency towards densification and enhanced molecular chain interactions,which can reduce the damage to the aggregated structure under tensile stress,while the reduced free volume inside the material and the shortened average free path of carriers can weaken the damage of high-energy electrons to molecular chains,thereby inhibiting the process of electrical tree *** results show that nucleating agents have great potential for maintaining the stable operation of XLPE cables under mechanical stress.

关键词： stress electrical damage

Decohesion of graphene from a uniaxially-stretched substrate:Failure analysis of a frictional adhesive interface

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Friction 2024年第3期12卷 510-521页

作者： Bo PENG Chaochen XU Qingao WANG Pei ZHAO Xiqiao FENG Qunyang LI AML Department of Engineering MechanicsTsinghua UniversityBeijing 100084China state Key Laboratory of Tribology in advanced Equipment Tsinghua UniversityBeijing 100084China center for X-Mechanics and Institute of Applied Mechanics Zhejiang UniversityHangzhou 310027China state Key Laboratory of Fluid power and M

Composite structures consisting of two-dimensional(2D)materials deposited on elastic substrates have a wide range of potential applications in flexible *** such devices,robust 2D film/substrate interfacial adhesion is essential for their reliable performance when subjected to external thermal and mechanical *** better understand the strength and failure behavior of the 2D film/substrate interfaces,two types of graphene/polymer samples with distinct interfacial adhesion properties are fabricated and tested by uniaxially stretching the *** on the interfacial adhesion,two drastically different debonding rates are observed,i.e.,rapid snap-through debonding and more progressive crack *** by the experimental observation,we propose an improved shear-lag model with a trapezoidal-shaped cohesive zone to derive an analytical solution for the decohesion *** theoretical model reveals that the decohesion behavior of the frictional adhesive interface is governed by three dimensionless ***,the dimensionless length of the film essentially determines the decohesion rate;while the other two parameters affect the critical substrate strain to initiate *** fitting the experimental data with the theoretical model,the intrinsic adhesion properties of the two samples are obtained with physically meaningful *** work offers an analytical solution to describing the decohesion behavior of general thin film/substrate systems with a frictional adhesive interface,which is beneficial for characterizing and optimizing the mechanical properties of various thin film/polymer devices.

关键词： film/substrate systems adhesion frictional sliding interface decohesion cohesive-zone model