To address the performance limitations of conventional LiPF6-carbonate electrolytes under extreme temperatures and high-rate charging,lithium difluoro(oxalato)borate(LiDFOB)is introduced into the LiPF6-carbonate elect...To address the performance limitations of conventional LiPF6-carbonate electrolytes under extreme temperatures and high-rate charging,lithium difluoro(oxalato)borate(LiDFOB)is introduced into the LiPF6-carbonate electrolyte to form a dual-salt system.The optimization mechanism enhancing the fast-charging capability of LiNi_(0.52)Co_(0.2)Mn_(0.28)O_(2)(NCM523)cathode is systematically explored.Molecular dynamics simulations and electrochemical characterization demonstrate the reconstruction of Li+solvation structures,expanding the voltage window and reducting Li^(+)desolvation barriers.In addition,the incorporation of LiDFOB induces the generation of a LiF/Li_(x)BO_(y)F_(z)-enriched cathode-electrolyte interphase,which effectively suppresses the dissolution of transition metals.In situ impedance measurements reveal the accelerated interfacial charge transfer kinetics.As expected,the NCM523 cathode achieves an 82%state-of-charge(SOC)in 12 min at 5 C(25°C)with 87%capacity retention after 100 cycles,and exhibits a 65%higher discharge capacity at 1 C than the baseline at−20°C.The 1 Ah pouch cells based on LiNi_(0.52)Co_(0.2)Mn_(0.28)O_(2)cathodes,graphite anodes,and 0.5 wt%LiDFOB-modified electrolyte demonstrate fast-charging capabilities:charging 97%of the pouch cell capacity within 30 min(2 C)and 80%within 15 min(4 C)at 25°C.This study offers a practical electrolyte design strategy that enhances the fast-charging performance of lithium-ion batteries(LIBs)over a wide temperature range(from−20 to 25°C).展开更多
为保障500 m口径球面射电望远镜(FAST)的安全稳定运行,提出基于实时信息数据的三维可视化监测方法。融合三维静态/动态建模、多源数据实时处理、Ansys仿真分析等关键技术,构建FAST高保真数字孪生模型,基于LightningChart图形库开发图形...为保障500 m口径球面射电望远镜(FAST)的安全稳定运行,提出基于实时信息数据的三维可视化监测方法。融合三维静态/动态建模、多源数据实时处理、Ansys仿真分析等关键技术,构建FAST高保真数字孪生模型,基于LightningChart图形库开发图形用户界面(graphical user interface,GUI)系统,实现设备异常信号的秒级可视化预警,故障响应时间显著缩短。该方法为大型射电望远镜及其阵列实施基于数字孪生的可视化监测提供参考。展开更多
针对500米口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)运行过程中存在馈源接收机安装及更换时设备精密且拆装过程复杂、馈源舱内安装空间狭小、馈源舱停靠平台处安装空间有限、连接螺栓数量多、...针对500米口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)运行过程中存在馈源接收机安装及更换时设备精密且拆装过程复杂、馈源舱内安装空间狭小、馈源舱停靠平台处安装空间有限、连接螺栓数量多、下平台尺寸重量大且安装精度要求高、更换时间长和运输困难等问题,提出FAST运行维护作业机器人总体技术解决方案。通过机器人总体技术需求分析、机器人总体技术设计、机器人关键技术研究及仿真分析,该方案可满足馈源接收机拆装过程中定位、识别、拆装和运输等应用需求,减小运行维护的时间成本和经济成本,确保FAST运行维护的安全,提高使用效率,延长FAST的全年观测时间,从而促进天文成果的产出。展开更多
非量测相机以价格低、体积小、使用灵活等优势被广泛应用于高精度测量工作中,但相机标定结果对测量精度影响较大,针对现有相机标定方法存在着精度不够或标定效率不高等问题,文章提出一种联合加速分割检测特征(features from accelerated...非量测相机以价格低、体积小、使用灵活等优势被广泛应用于高精度测量工作中,但相机标定结果对测量精度影响较大,针对现有相机标定方法存在着精度不够或标定效率不高等问题,文章提出一种联合加速分割检测特征(features from accelerated segment test,FAST)算法和双像光束法平差的相机标定方法。首先利用FAST算法对像片标志点自动提取,利用直接线性变换方法解得相机内、外参数初值;然后基于固定基线长度约束的双像光束法平差模型解算相机相关参数,并通过分类阈值方法提高模型收敛效率。结果表明:该方法相较于普通双像光束法平差的精度有所提升,其标定后的中误差达到0.0064 mm,且实现了相机标定流程的半自动化,提高了作业效率,有望应用于实际场景的相机标定作业。展开更多
The properties of electrolytes are critical for fast-charging and stable-cycling applications in lithium metal batteries(LMBs).However,the slow kinetics of Li^(+)transport and desolvation in commercial carbonate elect...The properties of electrolytes are critical for fast-charging and stable-cycling applications in lithium metal batteries(LMBs).However,the slow kinetics of Li^(+)transport and desolvation in commercial carbonate electrolytes,cou pled with the formation of unstable solid electrolyte interphases(SEI),exacerbate the degradation of LMB performance at high current densities.Herein,we propose a versatile electrolyte design strategy that incorporates cyclohexyl methyl ether(CME)as a co-solvent to reshape the Li^(+)solvation environment by the steric-hindrance effect of bulky molecules and their competitive coordination with other solvent molecules.Simulation calculations and spectral analysis demonstrate that the addition of CME molecules reduces the involvement of other solvent molecules in the Li solvation sheath and promotes the formation of Li^(+)-PF_(6)^(-)coordination,thereby accelerating Li^(+)transport kinetics.Additionally,this electrolyte composition improves Li^(+)desolvation kinetics and fosters the formation of inorganic-rich SEI,ensuring cycle stability under fast charging.Consequently,the Li‖LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)battery with the modified electrolyte retains 82% of its initial capacity after 463 cycles at 1 C.Even under the extreme fast-charging condition of 5 C,the battery can maintain 80% capacity retention after 173 cycles.This work provides a promising approach for the development of highperformance LMBs by modulating solvation environment of electrolytes.展开更多
With the continuous upgrading of traditional manufacturing industries and the rapid rise of emerging technology fields,the performance requirements for the permanent magnet synchronous motors(PMSMs)have become higher ...With the continuous upgrading of traditional manufacturing industries and the rapid rise of emerging technology fields,the performance requirements for the permanent magnet synchronous motors(PMSMs)have become higher and higher.The importance of fast and accurate electromagnetic thermal coupling analysis of such motors becomes more and more prominent.In view of this,the surfacemounted PMSM(SPMSM)equipped with unequally thick magnetic poles is taken as the main object and its electromagnetic thermal coupling analytical model(ETc AM)is investigated.First,the electromagnetic analytical model(EAM)is studied based on the modified subdomain method.It realizes the fast calculation of key electromagnetic characteristics.Subsequently,the 3D thermal analytical model(TAM)is developed by combining the EAM,the lumped parameter thermal network method(LPTNM),and the partial differential equation of heat flux.It realizes the fast calculation of key thermal characteristics in 3D space.Further,the information transfer channel between EAM and TAM is built with reference to the intrinsic connection between electromagnetic field and temperature field.Thereby,the novel ETcAM is proposed to realize the fast and accurate prediction of electromagnetic and temperature fields.Besides,ETcAM has a lot to commend it.One is that it well accounts for the complex structure,saturation,and heat exchange behavior.Second,it saves a lot of computer resources.It offers boundless possibilities for initial design,scheme evaluation,and optimization of motors.Finally,the validity,accuracy,and practicality of this study are verified by simulation and experiment.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.52372191)the National Natural Science Foundation of China(Grant No.22271106)+2 种基金the National Science Foundation of China(Grant Nos.52073286(C.-Z.L.),22275185(C.-Z.L.))the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ115(C.-Z.L.)the XMIREM Autonomously Deployment Project(2023GG01(C.-Z.L.)).We would like to thank the Instrumental Analysis Center of Huaqiao University for physical characterization(XRD and SEM).
文摘To address the performance limitations of conventional LiPF6-carbonate electrolytes under extreme temperatures and high-rate charging,lithium difluoro(oxalato)borate(LiDFOB)is introduced into the LiPF6-carbonate electrolyte to form a dual-salt system.The optimization mechanism enhancing the fast-charging capability of LiNi_(0.52)Co_(0.2)Mn_(0.28)O_(2)(NCM523)cathode is systematically explored.Molecular dynamics simulations and electrochemical characterization demonstrate the reconstruction of Li+solvation structures,expanding the voltage window and reducting Li^(+)desolvation barriers.In addition,the incorporation of LiDFOB induces the generation of a LiF/Li_(x)BO_(y)F_(z)-enriched cathode-electrolyte interphase,which effectively suppresses the dissolution of transition metals.In situ impedance measurements reveal the accelerated interfacial charge transfer kinetics.As expected,the NCM523 cathode achieves an 82%state-of-charge(SOC)in 12 min at 5 C(25°C)with 87%capacity retention after 100 cycles,and exhibits a 65%higher discharge capacity at 1 C than the baseline at−20°C.The 1 Ah pouch cells based on LiNi_(0.52)Co_(0.2)Mn_(0.28)O_(2)cathodes,graphite anodes,and 0.5 wt%LiDFOB-modified electrolyte demonstrate fast-charging capabilities:charging 97%of the pouch cell capacity within 30 min(2 C)and 80%within 15 min(4 C)at 25°C.This study offers a practical electrolyte design strategy that enhances the fast-charging performance of lithium-ion batteries(LIBs)over a wide temperature range(from−20 to 25°C).
文摘为保障500 m口径球面射电望远镜(FAST)的安全稳定运行,提出基于实时信息数据的三维可视化监测方法。融合三维静态/动态建模、多源数据实时处理、Ansys仿真分析等关键技术,构建FAST高保真数字孪生模型,基于LightningChart图形库开发图形用户界面(graphical user interface,GUI)系统,实现设备异常信号的秒级可视化预警,故障响应时间显著缩短。该方法为大型射电望远镜及其阵列实施基于数字孪生的可视化监测提供参考。
文摘针对500米口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)运行过程中存在馈源接收机安装及更换时设备精密且拆装过程复杂、馈源舱内安装空间狭小、馈源舱停靠平台处安装空间有限、连接螺栓数量多、下平台尺寸重量大且安装精度要求高、更换时间长和运输困难等问题,提出FAST运行维护作业机器人总体技术解决方案。通过机器人总体技术需求分析、机器人总体技术设计、机器人关键技术研究及仿真分析,该方案可满足馈源接收机拆装过程中定位、识别、拆装和运输等应用需求,减小运行维护的时间成本和经济成本,确保FAST运行维护的安全,提高使用效率,延长FAST的全年观测时间,从而促进天文成果的产出。
基金supported by the Lithium Resources and Lithium Materials Key Laboratory of Sichuan Province(LRMKF202405)the National Natural Science Foundation of China(52402226)+3 种基金the Natural Science Foundation of Sichuan Province(2024NSFSC1016)the Scientific Research Startup Foundation of Chengdu University of Technology(10912-KYQD2023-10240)the opening funding from Key Laboratory of Engineering Dielectrics and Its Application(Harbin University of Science and Technology)(KFM202507,Ministry of Education)the funding provided by the Alexander von Humboldt Foundation。
文摘The properties of electrolytes are critical for fast-charging and stable-cycling applications in lithium metal batteries(LMBs).However,the slow kinetics of Li^(+)transport and desolvation in commercial carbonate electrolytes,cou pled with the formation of unstable solid electrolyte interphases(SEI),exacerbate the degradation of LMB performance at high current densities.Herein,we propose a versatile electrolyte design strategy that incorporates cyclohexyl methyl ether(CME)as a co-solvent to reshape the Li^(+)solvation environment by the steric-hindrance effect of bulky molecules and their competitive coordination with other solvent molecules.Simulation calculations and spectral analysis demonstrate that the addition of CME molecules reduces the involvement of other solvent molecules in the Li solvation sheath and promotes the formation of Li^(+)-PF_(6)^(-)coordination,thereby accelerating Li^(+)transport kinetics.Additionally,this electrolyte composition improves Li^(+)desolvation kinetics and fosters the formation of inorganic-rich SEI,ensuring cycle stability under fast charging.Consequently,the Li‖LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)battery with the modified electrolyte retains 82% of its initial capacity after 463 cycles at 1 C.Even under the extreme fast-charging condition of 5 C,the battery can maintain 80% capacity retention after 173 cycles.This work provides a promising approach for the development of highperformance LMBs by modulating solvation environment of electrolytes.
基金supported by the Project of National Natural Science Foundation of China under Grant 52077122。
文摘With the continuous upgrading of traditional manufacturing industries and the rapid rise of emerging technology fields,the performance requirements for the permanent magnet synchronous motors(PMSMs)have become higher and higher.The importance of fast and accurate electromagnetic thermal coupling analysis of such motors becomes more and more prominent.In view of this,the surfacemounted PMSM(SPMSM)equipped with unequally thick magnetic poles is taken as the main object and its electromagnetic thermal coupling analytical model(ETc AM)is investigated.First,the electromagnetic analytical model(EAM)is studied based on the modified subdomain method.It realizes the fast calculation of key electromagnetic characteristics.Subsequently,the 3D thermal analytical model(TAM)is developed by combining the EAM,the lumped parameter thermal network method(LPTNM),and the partial differential equation of heat flux.It realizes the fast calculation of key thermal characteristics in 3D space.Further,the information transfer channel between EAM and TAM is built with reference to the intrinsic connection between electromagnetic field and temperature field.Thereby,the novel ETcAM is proposed to realize the fast and accurate prediction of electromagnetic and temperature fields.Besides,ETcAM has a lot to commend it.One is that it well accounts for the complex structure,saturation,and heat exchange behavior.Second,it saves a lot of computer resources.It offers boundless possibilities for initial design,scheme evaluation,and optimization of motors.Finally,the validity,accuracy,and practicality of this study are verified by simulation and experiment.
