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Stability Comparison Between Grid-forming and Grid-following Based Wind Farms Integrated MMC-HVDC

Journal of Modern Power Systems and Clean Energy 2023年第4期11卷 1341-1355页

作者： Rongcai Pan Dong Liu Shan Liu Jie Yang Longze Kou Guangfu Tang China Electric Power Research Institute Beijing 100192Chinaand he is also with the State Key Laboratory of Advanced Power Transmission Technology and Beijing Key Laboratory of DC Grid Technology&SimulationBeijing 102209China State Key Laboratory of Advanced Power Transmission Technology and Beijing Key Laboratory of DC Grid Technology&Simulation Beijing 102209China

Grid-forming(GFM)control based high-voltage DC(HVDC)systems and renewable energy sources(RESs)provide support for enhancing the stability of power ***,the interaction and coordination of frequency support between the GFM-based modular multilevel converter based HVDC(MMC-HVDC)and grid-following(GFL)based RESs or GFM-based RESs have not been fully investigated,which are examined in this ***,the detailed AC-and DC-side impedances of GFM-based MMC-HVDC are *** impedance characteristics of GFL-and GFM-based wind turbines are next ***,the influences of GFL-and GFM-based wind farms(WFs)on the DC-and AC-side stabilities of WF-integrated MMC-HVDC systems are compared and *** results show that the GFM-based wind turbine performs better than the GFL-based wind ***,to support a receiving-end AC system,the corresponding frequency supporting strategies are proposed based on the GFM control for WF-integrated MMC-HVDC *** GFM-based WF outperforms the GFL-based WF in terms of stability and response *** in PSCAD/EMTDC demonstrate the DC-and AC-side stability issues and seamless grid support from the RESs,i.e.,WFs,to the receiving-end AC system.

关键词： Renewable energy source(RES) modular multilevel converter(MMC) wind farm grid-forming(GFM) highvoltage direct current

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Precipitating thermally reinforcement phase in aluminum alloys for enhanced strength at 400℃

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Journal of Materials Science & technology 2024年第5期172卷 71-82页

作者： Xiang Su Yuan Lei Yang Chen Hongjie Qu Zhixiang Qi Gong Zheng Xu Liu Henggao Xiang Guang Chen National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China School of Aviation and Mechanical Engineering Changzhou Institute of TechnologyChangzhou 213032China

Heat-resistant aluminum alloys are widely used in aerospace and automotive fields for manufacturing hot components due to their advantages in lightweight design and energy ***,the high-temperature strength of existing cast aluminum alloys is always limited to about 100 MPa at 350℃due to coarsening and transformation of strengthening ***,we reveal that the yield strength and ultimate tensile strength of the T6 state Al-8.4Cu-2.3Ce-1.0Mn-0.5Ni-0.2Zr alloy at 400◦C increase by 34%and 44%after re-aging at 300℃for 100 h,and its thermal strength exhibits distinguished ad-vantage over traditional heat-resistant aluminum *** enhanced elevated-temperature strength is attributed to the reprecipitation of the Ni-bearing T-Al_(20)Cu_(2)Mn_(3)phase,whose number density increases over one *** significant segregation of Ni,Ce,and Zr elements at the interfaces helps improve the thermal stability of the T *** thermostable T phase effectively strengthens the matrix by in-hibiting dislocation ***,a highly interconnected 3D intermetallic network along the grain boundaries can still remain after long-term re-aging at 300℃,which is conducive to imposing a drag on the grain boundaries at high *** finding offers a viable route for enhancing the elevated-temperature strength of heat-resistant aluminum alloys,which could provide expanded opportunities for higher-temperature applications.

关键词： Aluminum alloys Precipitation Thermally reinforcement phase Re-aging treatment High-temperature strength

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In-situ X-ray computed tomography tensile tests and analysis of damage mechanism and mechanical properties in laser powder b e d fused Invar 36 alloy

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Journal of Materials Science & technology 2024年第8期175卷 29-46页

作者： Qidong Yang Shuo Yang Shiyu Ma Junhan Zhou Ye Zhou Rongzheng Huang Kai Wei Zhaoliang Qu Xujing Yang Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment Ministry of EducationHunan UniversityChangsha 410082China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China

Laser powder bed fusion(LPBF)is a potential additive manufacturing process to manufacture Invar 36 alloy components with complicated *** it inevitably introduces specific microstructures and pore defects,which will further influence the mechanical ***,aiming at exploring the LPBF process-related microstructures and pore defects,and especially their influences on the damage mechanism and mechanical properties,Invar 36 alloy was manufactured by LPBF under designed different laser scanning *** microstructure observations reveal that higher scanning speeds lead to equiaxed and short columnar grains with higher dislocation density,while lower scanning speeds result in elongated columnar grains with lower dislocation *** pore defects analyzed by X-ray computed tomography(XCT)suggest that the high laser scanning speed gives rise to numerous lamellar and large lack-of-fusion(LOF)pores,and the excessively low laser scanning speed produces relatively small keyhole pores with high ***,the insitu XCT tensile tests were originally performed to evaluate the damage evolution and failure ***,high laser scanning speed causes brittle fracture due to the rapid growth and coalescence of initial lamellar LOF pores along the scan-ning *** laser scanning speed induces ductile fracture originating from unstable depressions in the surfaces,while metallurgical and keyhole pores have little impact on damage ***,the process-structure-property correlation is *** presence of high volume fraction of lamel-lar LOF pores,resulting from high scanning speed,leads to inferior yield strength and ***,specimens without LOF pores exhibit larger grain sizes and lower dislocation density at decreased scanning speeds,slightly reducing yield strength while slightly enhancing *** understanding lays the foundation for widespread applications of LPBF-processed Invar 36 alloy

关键词： Invar 36 alloy Laser powder bed fusion Microstructure Pore defects Mechanical property X-ray tomography in-situ tensile test

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Effect of Symmetric Delay on Airfoil Plunging

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Journal of Bionic Engineering 2024年第6期21卷 2864-2876页

作者： Mostafa El-Salamony State Key Laboratory of Turbulence and Complex Systems Collaborative Innovation Center of Advanced Aero-EnginePeking UniversityBeijing100871China Institute of Aviation Engineering and Technology CairoEgypt

Delaying the sinusoidal plunging in the middle of the up-and down stroke is *** form of kinematics can appear if the flapping mechanism is malfunctioning,or while large birds fly in some *** of this study is to understand the effect of pausing the airfoil during plunging in the equilibrium *** paused plunging is modelled mathematically by means of a sinusoidal waveform raised to the third *** of this waveform is done on two stages;the wake pattern analysis and the aerodynamic and propulsive *** this waveform reveals a robust way to generate two triads wake pattern instead of the regular reverse von Karman vortex wake *** thrust generation mechanism is *** performance evaluation is done based on the thrust,lift,and power coefficients and the propulsive efficiency at different point in the nondimensional amplitude–reduced frequency *** modeling methods are utilized to stand on the performance of the paused waveform with respect to the regular sinusoidal *** findings underscore the potential of the proposed waveform as a promising alternative for enhancing the aerodynamic performance and propulsive efficiency in the design of Micro Air Vehicles(MAVs),a rapidly evolving field.

关键词： Unsteady aerodynamics Wake structure Plunging Flapping Fluid structure interaction Vortex MAV

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CC@BCN@PANI core-shell nanoarrays as ultra-high cycle stability cathode for Zn-ion hybrid supercapacitors

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Frontiers in Energy 2023年第4期17卷 555-566页

作者： Shixian XIONG Hongcheng KE Lei CAO Yu WANG Qian ZHU Liqin ZHONG Lanlan FAN Feng GU Nanchang Key Laboratory for Advanced Manufacturing of Electronic Information Materials and Devices/Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate Systems International Institute for InnovationJiangxi University of Science and TechnologyNanchang330013China

Exploring cathode materials that combine excellent cycling stability and high energy density poses a challenge to aqueous Zn-ion hybrid supercapacitors(ZHSCs).Herein,polyaniline(PANI)coated boron-carbon-nitrogen(BCN)nanoarray on carbon cloth surface is prepared as advanced cathode materials via simple high-temperature calcination and electrochemical deposition *** of the excellent specific capacity and conductivity of PANI,the CC@BCN@PANI core-shell nanoarrays cathode shows an excellent ion storage ***,the 3D nanoarray structure can provide enough space for the volume expansion and contraction of PANI in the charging/discharging cycles,which effectively avoids the collapse of the microstructure and greatly improves the electrochemical stability of ***,the CC@BCN@PANI-based ZHSCs exhibit superior electrochemical performances showing a specific capacity of 145.8 mAh/g,a high energy density of 116.78 Wh/kg,an excellent power density of 12 kW/kg,and a capacity retention rate of 86.2%after 8000 charge/discharge cycles at a current density of 2 A/*** addition,the flexible ZHSCs(FZHSCs)also show a capacity retention rate of 87.7%at the current density of 2 A/g after 450 cycles.

关键词： CC@BCN@PANI cathode Zn-ion hybrid supercapacitor core-shell nanoarrays high energy density ultra-high cycle stability

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MilChat: A Large Language Model and Application for Military Equipment 7

MilChat: A Large Language Model and Application for Military...

引用

7th International Conference on Machine Learning and Natural Language Processing, MLNLP 2024

作者： Xue, Liu Jie, Liu Peipei, Zhu Tao, Xiang Southwest China Institute of Electronic Technology National Key Laboratory of Complex Aviation System Simulation Chengdu China

ISBN: (纸本)9798350354973

To offer the military personnel a good service of assisting them to get information about enemy's equipment outside Internet, we build a system named MilChat which includes a large language model that has the ability to generate texts and an application which is easy to use. The model of MilChat is fine-tuned by the method of LoRA with military datasets from the basic model, Qwen-7B-Chat which is opensource and has good performance. After fine-tuning, the new model has higher scores than the basic one. Besides, we use the method of Prompt Learning to limit the answers into a standard format. Therefore, it is more accurate and professional than the basic model. This study has also a value of industrial application. © 2024 IEEE.

关键词： Military equipment

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Trial application of the envelope method to the potential ambiguity problem

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Nuclear Science and Techniques 2024年第1期35卷 73-80页

作者： Li-Yuan Hu Yu-Shou Song Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering UniversityHarbin 150001China College of Nuclear Science and Technology Harbin Engineering UniversityHarbin 150001China Key Laboratory of Nuclear Safety and Advanced Nuclear Energy Technology Ministry of Industry and Information TechnologyHarbin 150001China

The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering *** a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and farside scattering *** contrast,the envelope method can decompose the experimental data into two components with negative and positive deflection angles,***,a question arises as to whether the comparison between the calculated nearside(or farside)component and the derived positive-deflection-angle(or negative-deflection-angle)component can help analyze the potential ambiguity *** this study,we conducted a trial application of the envelope method to the potential ambiguity *** envelope method was improved by including uncertainties in the experimental *** colliding systems of 16O+28Si at 215.2 MeV and 12C+12C at 1016 MeV were considered in the *** each colliding system,the angular distribution experimental data were described nearly equally well by two potential sets,one of which is“surface transpar-ent”and the other is *** calculated angular distributions were decomposed into nearside and farside scattering *** the improved envelope method,the experimental data were decomposed into the positive-deflection-angle and negative-deflection-angle components,which were then compared with the calculated nearside and farside *** capability of the envelope method to analyze the potential ambiguities was also discussed.

关键词： Elastic scattering Optical potential ambiguities Envelope method Nearside/farside decomposition

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Electronic structure and carrier mobility of BSb nanotubes

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Chinese Physics B 2025年第3期34卷 183-188页

作者： Lantian Xue Chennan Song Miaomiao Jian Qiang Xu Yuhao Fu Pengyue Gao Yu Xie State Key Laboratory of High Pressure and Superhard Materials College of PhysicsJilin UniversityChangchun 130012China Key Laboratory of Material Simulation Methods&Software of Ministry of Education College of PhysicsJilin UniversityChangchun 130012China Key Laboratory of Physics and Technology for Advanced Batteries of Ministry of Education College of PhysicsJilin UniversityChangchun 130012China

High-mobility semiconductor nanotubes have demonstrated great potential for applications in high-speed transistors,single-charge detection,and memory *** we systematically investigated the electronic properties of single-walled boron antimonide(BSb)nanotubes using first-principles *** observed that rolling the hexagonal boron antimonide monolayer into armchair(ANT)and zigzag(ZNT)nanotubes induces compression and wrinkling effects,significantly modifying the band structures and carrier mobilities through band folding andπ^(*)-σ^(*)*** the chiral index increases,the band gap and carrier mobility of ANTs decrease monotonically,where electron mobility consistently exceeds hole *** contrast,ZNTs exhibit a more complex trend:the band gap first increases and then decreases,and the carrier mobility displays oscillatory *** particular,both ANTs and ZNTs could exhibit significantly higher carrier mobilities compared to hexagonal monolayer and zinc-blende BSb,reaching 10^(-3)-10^(-7) cm^(-2)·V^(-1)·s^(-1).Our findings highlight strong curvature-induced modifications in the electronic properties of single-walled BSb nanotubes,demonstrating the latter as a promising candidate for high-performance electronic devices.

关键词： ab initio calculations nanotubes electronic structure carrier mobility

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Realizing large strain at low electric field in Pb(Zr,Ti)O_(3)-based piezoelectric ceramics via engineering lattice distortion and domain structure

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Journal of advanced Ceramics 2024年第9期13卷 1409-1421页

作者： Denghui Jiang Feng Luo Kao Pei Hongyu Yang Linzhuang Xing Yangxi Yan Mo Zhao Zhimin Li Yue Hao School of Advanced Materials and Nanotechnology Xidian UniversityXi’an 710126China Academy of Advanced Interdisciplinary Research Xidian UniversityXi’an 710071China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect(Northwest Institute of Nuclear Technology) Xi’an 710024China National Key Laboratory of Wide Bandgap Semiconductor Devices and Integrated Technology Xidian UniversityXi’an 710071China

Pb(Zr,Ti)O_(3)-based ceramics are the mainstream materials for commercial multilayer piezoelectric ceramic actuators,but to date,large strains at low electric fields have not been well ***,0.95Pb(Zr_(0.56)Ti_(0.44))O_(3)–0.05(Bi_(0.5)Na_(0.5))TiO_(3–x)BaZrO_(3)(PZT–BNT–xBZ)ceramics with efficient ferroelectric domain wall motion were designed and realized by reducing lattice distortion and changing the domain *** is found that the introduction of BaZrO_(3)(BZ)weakens the tetragonal phase distortion of PZT,contributing to a reduction in the mechanical stress that impedes the migration of domain ***,the domain structures could be modified by adjusting the BZ content,where short and broad striped domains are constructed with high amplitude characteristics to enhance the domain wall motion.A large strain of 0.39%is accordingly achieved at an electric field as low as 40 kV/cm for the sample with x=0.03,accompanied by excellent temperature stability over the temperature range of 30–210℃.This study delves into the synergistic effects of reducing lattice distortion and changing domain structure on domain wall motion and provides an effective strategy to improve the strain of PZT-based piezoelectric ceramics.

关键词： PZT ceramic strain ferroelectric domain lattice distortion

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Evidence of microstructural evolution linked to non-monotonic distribution of micromechanical properties induced by shot peening

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材料科学技术（英文版） 2025年第4期207卷 238-245页

作者： Guoxin Lu Qiang Wang Bonnie Attard Huhu Su Shijian Zheng Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationSchool of Materials Science and EngineeringShandong UniversityJinan250061China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material AECC Beijing Institute of Aeronautical MaterialsBeijing100095China Department of Metallurgy and Materials Engineering University of MaltaMSD2080Malta Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology School of Materials Science and EngineeringHebei University of TechnologyTianjin300130China

The residual stress field induced by surface strengthening processes such as mechanical shot peening and other forms of plastic deformation does not generally exhibit a simple"monotonic"distribution *** researchers have analyzed this fact from a mechanical perspective based on Hertz ***,the micro/nano-scale microstructural changes corresponding to the distribution of residual stress fields still appear to be *** this study,we focused on a widely used material in aviation manufacturing,namely nickel-based superalloy GH4169,as our experimental *** subjected GH4169 alloy to me-chanical strengthening treatment using a shot peening intensity of 0.25 mmA,followed by quantitative testing of micromechanical performance indicators such as microhardness and residual *** thor-oughly investigate the relationship between micromechanical properties and microstructure changes,we utilized transmission electron microscopy(TEM)to observe and analyze shot-peened materials at differ-ent *** findings revealed that the most severe microstructural distortion induced by mechanical shot peening in GH4169 alloy was likely to occur within a depth range of 25 to 75 *** observation aligns with the actual phenomenon that the maximum microhardness and maximum residual compres-sive stress did not manifest on the outermost surface of the *** presenting a detailed analysis of deformation defects such as dislocations,stacking faults,and twinning in different depths of mechan-ically strengthened layers,our study contributes to a deeper understanding and practical application of post-processing technologies based on plastic deformation.

关键词： Mechanical shot peening Surface strengthening Residual stress Microstructure

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