检索结果-南通市图书馆

Multi-physical fields distribution in billet during helical electromagnetic stirring:A numerical simulation research

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

china Foundry 2024年第1期21卷 51-59页

作者： Dong Pan Qing-tao Guo Kai-lun Zhang Fu-zhi Yu Yu-ying Li Yu-bao Xiao State Key Laboratory of Metal Materials for Marine equipment and Application Anshan 114009LiaoningChina Ansteel Beijing research institute co. Ltd.Beijing 102200China

Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting *** from co.ventional rotate stirring,the helical stirring is more professional in assisting multi-dimensional flow of molten metal and eliminating solidification *** this study,the single-winding helical stirring(SWHS)was introduced,offering advantages such as smaller volume and lower electromagnetic shielding co.pared to traditional helical stirring *** a co.prehensive numerical simulation,the stirring parameters of SWHS were adjusted to yoke inclination angle of 43°and frequency of 12 *** higher electromagnetic force and flow velocity in drawing direction,as well as the lower temperature gradient induced by the SWHS,are positive factors for homogeneous solidification of *** experimental results on Al-8%Si alloy and 0.4%C-1.1%Mn steel demonstrate that co.pared to rotate stirring,the SWHS process can induce better billet quality and is more effective in accelerating the equiaxed expansion and reducing element *** SWHS process can enhance the equiaxed ratio of the billet by 58.3%and reduce segregation degree of carbon element by 10.97%.co.sequently,SWHS holds great promise as a potential approach for improving the quality of co.tinuous casting billets.

关键词： billet electromagnetic stirring helical solidification element segregation numerical simulation

co.mand filtered integrated estimation guidance and co.trol for strapdown missiles with circular field of view

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第5期35卷 211-221页

作者： Wei Wang Jiaqi Liu Shiyao Lin Baokui Geng Zhongjiao Shi School of Aerospace Engineering Beijing Institute of TechnologyBeijing 10081China china research and Development Academy of Machinery equipment Beijing 100089China Northwest Industries Group co. Ltd.Xi'an 710043China

In this paper,an integrated estimation guidance and co.trol(IEGC)system is designed based on the co.mand filtered backstepping approach for circular field-of-view(FOV)strapdown *** threedimensional integrated estimation guidance and co.trol nonlinear model with limited actuator deflection angle is established co.sidering the seeker's FOV *** boundary time-varying integral barrier Lyapunov function(IBLF)is employed in backstepping design to co.strain the body line-of-sight(BLOS)in IEGC system to fit a circular ***,the nonlinear adaptive co.troller is designed to estimate the changing aerodynamic *** generalized extended state observer(GESO)is designed to estimate the acceleration of the maneuvering targets and the unmatched time-varying disturbances for improving tracking ***,the co.mand filters are used to solve the"differential expansion"problem during the backstepping *** Lyapunov theory is used to prove the stability of the overall closed-loop IEGC ***,the simulation results validate the integrated system's effectiveness,achieving high accuracy strikes against maneuvering targets.

关键词： Integrated estimation guidance and co.trol Circular field-of-view Time-varying integral barrier Lyapunov function co.mand filtered backstepping co.trol Nonlinear adaptive co.trol Extended state observer

Thermofluidic investigations of oil natural transformer:Closed-loop modelling and experimental validation

在线全文

学校读者我要写书评

暂无评论

High Voltage 2024年第1期9卷 230-240页

作者： Yuan Li Yiran Gao Chen Wang Chao Zhu Ying Li Yuankai Wang Guanjun Zhang State Key Laboratory of Electrical Insulation and Power equipment Xi'an Jiaotong UniversityXi'anChina Electric Power research institute of State Grid Shaanxi Electric Power co. Ltd.Xi'anChina TBEA Hengyang Transformer co. Ltd.HengyangChina

Excessively high temperatures inside a power transformer can accelerate the ageing rate and even cause unplanned *** estimating the hot-spot temperature(HST)of a power transformer is important for regulating the load and ensuring long-term *** this study,a closed-loop model of a 110-kV product transformer with an oil natural/air forced(ONAF)co.ling mode is built to predict HST,in which the co.pression ratio of windings,equivalent heat source and radiator geometry are *** to the flow field of the winding,the‘dead oil zone’and reverse oil flow are observed in the horizontal oil *** accuracy of the proposed model is experimentally validated by temperature-rise *** results show that the absolute errors between the measured results and simulation are below 5°C,and the average error is~2°***,the arrangements of windings and radiators are studied to enhance the oil *** adding 5 washers to the high-voltage winding,the average temperature can be decreased by 6°C co.pared with the case without a *** the radiator can also mitigate the characteristic temperatures,and the optimal height difference between the radiator and winding centre is suggested to be 0.66 m.

关键词： winding arrangement adding

Multi-scale modeling for prediction of mechanical performance in brazed GH99 thin-walled structure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第7期37卷 550-563页

作者： Yazhou LIU Shengpeng HU Yanyu SONG Wei FU Xiaoguo SONG Ning GUO Weimin LONG State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Shandong institute of Shipbuilding Technology Weihai 264209China china Machinery Intelligent equipment Innovation research institute(Ningbo)co. Ltd.Ningbo 315700China

Superalloy thin-walled structures are achieved mainly by brazing,but the deformation process of brazed joints is non-uniform,making it a challenging research *** paper reco.ds a thorough investigation of the effect of brazing parameters on the microstructure of joints and its mechanical properties,which mainly inquires into the deformation and fracture mechanisms in the shearing process of GH99/BNi-5a/GH99 *** macrosco.ic-microsco.ic deformation mechanism of the brazing interface during shearing was studied by Crystal Plasticity(CP)and Molecular Dynamics(MD)on the basis of the optimal brazing *** experimental results show that the brazing interface is mainly formed by(Ni,Cr,co.(s,s)and possesses a shear strength of approximately 546 *** shearing fracture of the brazed joint occurs along the brazing seam,displaying the characteristics of intergranular *** simulations show that dislocations disassociate and transform into fine twinning with increased *** simulated the shear deformation process of the brazed *** multiscale simulation results are co.sistent with the experimental *** mechanical properties of thin-walled materials for brazing are predicted using MD and CP methods.

关键词： Multi-scale modeling Brazing Shear mechanisms Crystal plasticity GH99 superalloy

Fabricating functionally graded Fe-Cr-co.permanent magnetic alloys via laser powder bed fusion

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel research International 2024年第3期31卷 729-737页

作者： Ya-zhou He Ya-qing Hou Peng Shen Hao Zhang Dong Zhou Hang Su Central Iron and Steel research institute co. Ltd.Beijing 100081China Material Digital R&D Center China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China

Laser powder bed fusion(LPBF)in-situ alloying technology offers the possibility to co.struct gradient materials with varied structures and *** graded Fe-Cr-co.permanent magnetic alloys were fabricated by LPBF and in-situ alloying mixed powders of Fe,Cr,and co.*** effects of different Fe,Cr and co.co.tents on the microstructure,magnetic properties and hardness of Fe-Cr-co.alloys prepared by LPBF were *** as-built Fe-Cr-co.alloys present a single body-centered-cubic phase and have a homogeneous distribution of *** mechanical properties and magnetic properties of the co.positionally graded sample show a gradient *** the increase in Cr co.tent,the Vickers hardness of the sample increases,and the saturation magnetization of the sample *** optimal magnetic properties in an isotropic state are given as co.rcivity HcB=21.65 kA/m,remanence Br=0.70 T and energy product(BH)_(max)=5.35 kJ/m^(3),which are co.parable to or higher than the reported magnetic properties in an isotropic state prepared by traditional powder *** in-situ alloying technology has the potential to further explore Fe-Cr-co.magnetic materials,such as those co.sisting of multiple or more co.stituent elements,and to maximize the co.positional flexibility of magnetic materials.

关键词： Fe-Cr-co.alloy Laser powder bed fusion In-situ alloying Functional material Magnetic property

Neural Network Robust co.trol Based on co.puted Torque for Lower Limb Exoskeleton

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第2期37卷 83-99页

作者： Yibo Han Hongtao Ma Yapeng Wang Di Shi Yanggang Feng Xianzhong Li Yanjun Shi Xilun Ding Wuxiang Zhang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Beihang Goer(WeiFang)Intelligent Robot co. Ltd.Beihang UniversityWeifangChina research Center of Satellite Technology Harbin Institute of TechnologyHarbinChina Beijing Xinfeng Aerospace equipment co. LtdBeijingChina

The lower limb exoskeletons are used to assist wearers in various scenarios such as medical and industrial *** modeling errors of the exoskeleton in different application scenarios pose challenges to the robustness and stability of its co.trol *** Radial Basis Function(RBF)neural network is used widely to co.pensate for modeling *** order to solve the problem that the current RBF neural network co.trollers cannot guarantee the asymptotic stability,a neural network robust co.trol algorithm based on co.puted torque method is proposed in this paper,focusing on trajectory *** innovatively inco.porates the robust adaptive term while introducing the RBF neural network term,improving the co.pensation ability for modeling *** stability of the algorithm is proved by Lyapunov method,and the effectiveness of the robust adaptive term is verified by the *** wearing the exoskeleton under different walking speeds and scenarios were carried out,and the results show that the absolute value of tracking errors of the hip and knee joints of the exoskeleton are co.sistently less than 1.5°and 2.5°,*** proposed co.trol algorithm effectively co.pensates for modeling errors and exhibits high robustness.

关键词： Lower limb exoskeleton Model co.pensation RBF neural network co.puted torque method

Understanding the co.bustion behavior of electric bicycle batteries and unveiling its relationship with fire extinguishing

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第4期91卷 609-618页

作者： Zhanglong Yu Xueling Shen Ran Xu Zheng Wang Zengming Wan Mingyang Chen Yi Cui Yanyan Fang Xiaoli Ma china Automotive Battery research institute co. Ltd.Beijing 101407China china Grinm Group co. Ltd.Beijing 100088China Ministry of Industry and Information Technology Equipment Industry Development CenterBeijing 100846China Hefei Guoxuan High-tech Power energy co. Ltd.Hefei 230000AnhuiChina

In this study,a detailed analysis of the co.bustion behaviors of the lithium iron phosphate(LFP)and lithium manganese oxide(LMO)batteries used in electric bicycles was *** research included quantitative measurements of the co.bustion duration,flame height,co.bustion temperature,heat release rate,and total heat *** results indicated that LMO batteries exhibited higher co.bustion temperatures of 600–700°C,flame heights of 70–75 cm,a significantly higher heat release rate of40.1 k W(12 Ah),and a total heat release of 1.04 MJ(12 Ah)co.pared to LFP batteries with the same *** on these experimental results,a normalized total heat release(NORTHR)parameter was proposed,demonstrating good universality for batteries with different *** this parameter,quantitative calculations and optimization of the extinguishing agent dosage were co.ducted for fires involving these two types of batteries,and the method was validated by extinguishing fires for these two types of battery packs with water-based extinguishing fluids.

关键词： co.bustion behavior Electric bicycle Lithium-ion battery Fire extinguishing Normalized total heat release

Atomistic mechanism of high ionic co.ductivity in lithium ytterbium-based halide solid electrolytes:A first-principles study

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第1期42卷 155-162,I0006页

作者： Limin Wang Wei Xiao Lu Sun Rong Yang Jinqiu Yu Ligen Wang State Key Laboratory of Nonferrous Metals and Processes China GRINM Group Co.Ltd.Beijing100088China GRIMAT Engineering institute co. Ltd.Beijing101407China General research institute for Nonferrous Metals Beijing100088China china Automotive Battery research institute co. Ltd.Beijing101407China Rare Earth Functional Materials(Xiong'an)Innovation Center co. Ltd.Xiong'an071700China

As the next generation of co.mercial automotive power batteries begins replacing liquid lithium batteries,many look towards all-solid-state batteries to pioneer the ***-so lid-state batteries have attracted the attention of co.ntless researchers around the world because of their high safety and high energy *** recent times,halide solid-state electrolytes have beco.e a research hotspot within solid-state electrolytes because of their potentially superior *** this paper,in the framework of DFT,we investigated the atomic mechanisms of improving the ionic co.ductivity and stability of Li_(3)YbCl_(6).Our calculations show that both trigonal and orthorhombic Li_(3)YbCl_(6) exhibit wide electrochemical windows and metastable properties(100 meV/atom>Ehull>0 meV/atom).However,the orthorhombic Li_(3)YbCl_(6) can be stabilized at high temperatures by taking the vibrational entropy into acco.nt,which is supported by the experimental ***,it is expected that because of the Yb/Li synergistic interactions that,due to their strong mutual co.lomb repulsion,influence the Li^(+)transport behavior,the orthorhombic Li_(3)YbCl_(6) might have superior ionic co.ductivities with appropriate Li+migration paths determined by the Yb^(3+) ***,higher ionic co.ductivities can be obtained by regulating the random distribution of Li^(+) *** Li^(+)-deficiency can also largely increase the ionic co.ductivity by invoking *** study helps gain a deeper understanding of the laws that govern ionic co.ductivities and stabilities and provides a certain theoretical reference for the experimental development and design of halide solid-state electrolytes.

关键词： Halide solid-state electrolytes Phase stability Ionic co.ductivity First-principles calculations Rare earths

Experimental investigation of bed-to-wall heat transfer in fluidized beds of a Geldart B sorbent particle under a full spectrum of fluidization regime

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第10期93卷 235-246页

作者： Chenhuan Xu Yongmin Zhang Liang Wang Yiming Zhang Tianlei Yang Feng Qiu Cenfan Liu Shuai Jiang Ke Dong State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Beijing DERUNCHEN Environmental Protection Technology co. LtdBeijing100022China Key Laboratory of Special equipment Safety and Energy-saving for State Market Regulation China Special Equipment Inspection and Research InstituteBeijing100029China

Fluidization technology has been used in co.(2) capture processes, the successful design and operation of the heat exchangers involved in this process require much information on the bed-to-wall heat transfer of the sorbent particles in fluidized states. In this study, the bed-to-wall heat transfer co.fficient (h) of a solid amine sorbent was measured by a heat transfer probe in a large-scale circulating fluidized bed co.d model unit, where full spectrum of fluidization regimes can be realized. The co.responding hydrodynamic signals were also studied by pressure sensors and optical fiber probes to further explain the newly disco.ered phenomenon. The results show that in a dense bed, due to the co.nterbalanced effect of time fraction of packet and packet renewal frequency, h of the Geldart B particle reaches a peak within the bubbling fluidized regime, and the radial distribution of h are opposite in bubbling and turbulent fluidized regimes. In a fast fluidization regime, gas co.vection beco.es the dominant factor affecting h when the solids holdup is low enough. co.relations were provided or reco.mended to guide the design of heat exchangers in the fluidized bed co.(2) capture processes.

关键词： Bed-to-wall heattransfer Solid amine sorbent Geldart B particle Full spectrum of fluidization regime co.relation