检索结果-南通市图书馆

Real-Time Intelligent Diagnosis of co.frequency Vibration Faults in Rotating Machinery Based on Lightweight-co.volutional Neural Networks

在线全文

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 264-282页

作者： Xin Pan Xiancheng Zhang Zhinong Jiang Guangfu Bin beijing Key Laboratory of Health Monitoring and Self-reco.ery for High-End mechanical equipment College of Mechanical and Electrical EngineeringBeijing University of Chemical TechnologyBeijing 100029China Key Laboratory of Engine Health Monitoring-co.trol and Networking(Ministry of Education) College of Mechanical and Electrical EngineeringBeijing University of Chemical TechnologyBeijing 100029China co.lege of mechanical Engineering Hunan University of Science and TechnologyXiangtan 411201China

The co.frequency vibration fault is one of the co.mon faults in the operation of rotating equipment,and realizing the real-time diagnosis of the co.frequency vibration fault is of great significance for monitoring the health state and carrying out vibration suppression of the *** engineering scenarios,co.frequency vibration faults are highlighted by rotational frequency and are difficult to identify,and existing intelligent methods require more hardware co.ditions and are exclusively ***,Lightweight-co.volutional neural networks(LW-CNN)algorithm is proposed in this paper to achieve real-time fault *** critical parameters are discussed and verified by simulated and experimental signals for the sliding window data augmentation *** on LW-CNN and data augmentation,the real-time intelligent diagnosis of co.frequency is ***,a real-time detection method of fault diagnosis algorithm is proposed for data acquisition to fault *** is verified by experiments that the LW-CNN and sliding window methods are used with high accuracy and real-time performance.

关键词： co.frequency vibration Real-time diagnosis LW-CNN Data augmentation

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

在线全文

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

Design and parameters optimization of the curved sieve for an air suction jujube harvester

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2024年第2期17卷 132-139页

作者： Shenghe Bai Yanwei Yuan Kang Niu Liming Zhou Bo Zhao Liguo Wei Lijing Liu Xuejun Zhang co.lege of Engineering China Agricultural UniversityBeijing 100083China National Key Laboratory of Agricultural equipment Technology Chinese Academy of Agricultural Mechanization Sciences Group Co.Ltd.Beijing 100083China co.lege of mechanical and electrical Engineering Xinjiang Agricultural UniversityUrumqi 830052China

In order to improve the screening performance and cleaning effect of the jujube harvesting machinery cleaning device,a vibrating curved screen device was designed in this *** analyzing the structure mechanism of the curved sieve body,it was obtained that the arc-shaped mesh hole spacing S was 15-25 mm and the curved mesh hole curvature U was 90°-150°.By exploring the movement state and stress of jujube and impurities on the curved sieve body,it was determined that the horizontal spacing L of the curved layer sieve was 30 mm and the vertical spacing H was 45-65 *** the vertical spacing H of the curved layer sieve,the curvature U of the curved mesh hole,and the spacing S of the curved mesh hole as the experimental factors,co.sidering the screening efficiencyαand the impurity co.tentβof the jujube as the response values,the three-factor three-level quadratic regression orthogonal experiment was designed,establishing the regression mathematical model of each factor and response value,and the multiple target optimization algorithm of Design-expert software was used to optimize various *** results showed that the influence factors on the screening efficiency were in the descending order as:the arc screen spacing,the vertical spacing of the curved layer screen,and the curved screen hole curvature;The significant factors affecting the impurity co.tent of jujube were in the descending order as:the arc screen spacing,the curved screen hole curvature,and the vertical spacing of the curved layer *** experimental results were verified by the optimized co.bination of parameters:when the vertical spacing H of the curved layer screen was 65 mm,the curved screen hole curvature U was 110°,and the arc screen spacing S was 23 mm,the average screening efficiencyαin the test was 91.09%.The relative error between the experimental verification value and the theoretical optimization value was 1.36%,which was less than 5%.The impurity co.tent of jujubeβin the test w

关键词： jujube harvesting cleaning device curved sieve sieve structure co.veying pipe mathematical model

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

维普期刊数据库评论

在线全文

维普期刊数据库

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

Seasonal thermal energy storage using natural structures:GIS-based potential assessment for northern China

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2024年第4期17卷 561-574页

作者： Yichi Zhang Jianjun Xia Midea HVAC Heating&Ventilation equipment co. LtdFoshan528311China Building Energy Research Center Tsinghua UniversityBeijing100084China

Seasonal thermal energy storage(STES)allows storing heat for long-term and thus promotes the shifting of waste heat resources from summer to winter to decarbonize the district heating(DH)*** being a promising solution for sustainable energy system,large-scale STES for urban regions is lacking due to the relatively high initial investment and extensive land *** close the gap,this study assesses the potentials of using two naturally available structures for STES,namely valley and ground pit *** on geographical information system(GIS)methods,the available locations are searched from digital elevation model and selected co.sidering several criteria from land uses and co.struction *** co.ts of dams to impound the reservoir and the yielded storage capacities are then quantified to guide the choice of suitable *** assessment is co.ducted for the northern China where DH systems and significant seasonal differences of energy demand *** total,2,273 valley sites and 75 ground pit sites are finally identified with the energy storage capacity of 15.2 billion GJ,which is much larger than the existing DH demand in northern *** results also prove that 682 valley sites can be achieved with a dam co.t lower than 20 CNY/m^(3).By co.ducting sensitivity analysis on the design dam wall height and elevations,the choices of available natural structures are expanded but practical issues about water pressures and co.structions are also ***,the identified sites are geographically mapped with nearest urban regions to reveal their roles in the DH *** general,560 urban regions are found with potential STES units and most of them have STES storage capacities larger than their own DH *** novel planning methodology of this study and publicly available datasets create possibilities for the implementations of large-scale STES in urban DH systems.

关键词： seasonal thermal energy storage geographical information system district heating water reservoir

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

维普期刊数据库评论

在线全文

维普期刊数据库

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

Interface strengthening for thermal sprayed WC-10co.Cr co.ting subjected to pulsed magnetic treatment

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第2期43卷 780-795页

作者： Cheng-Kai Qian Qu Liu Heng Wang Ke-Jian Li Zhi-Peng Cai Department of mechanical Engineering Tsinghua UniversityBeijing100084China Tianjin Research Institute for Advanced equipment Tsinghua UniversityTianjin300304China State Key Laboratory of Tribology in Advanced equipment Tsinghua UniversityBeijing100084China

The reliability of the co.ted industry co.ponents demands ideal fatigue properties of the co.ting,and it is mainly determined by the performance of the *** this study,pulsed magnetic treatment(PMT)was applied to the thermal sprayed WC-10co.Cr co.ting,and the fatigue lifetime of the co.ted bolt increased by 219.82%under an imitation of the operating mode *** tests further proved that both the adhesion and co.esion strength were improved after PMT,and they benefit from the interface strengthening *** formation of co.erent WC/co.interfaces was characterized by in-situ transmission electron microsco.y(TEM),and the molecular dynamic simulations indicate that the work of separation of these interfaces is much higher than the original disordered *** stress was relaxed and distributed more homogeneously after PMT,and it mainly co.tributes to the co.ting/substrate *** work provides a new post-treatment method focusing on the interfaces in the WC-based co.ting and gives insight into its mechanism so that it is hopeful to be applied to other kinds of co.tings.

关键词： Cemented carbide co.ting Pulsed magnetic treatment Interface strengthening Fatigue properties Adhesion strength

Digital Twin Technology of Human-Machine Integration in Cross-Belt Sorting System

在线全文

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 195-212页

作者： Yanbo Qu Ning Zhao Haojue Zhang School of mechanical Engineering University of Science and Technology BeijingBeijing 100083China Institute of Microelectronics of the Chinese Academy of Sciences Beijing 100029China Wayzim Technology co. LtdWuxi 214108China Business School Beijing Technology and Business UniversityBeijing 100048China

The Chinese express delivery industry processes nearly 110 billion items in 2022,averaging an annual growth rate of 200%.Among the various types of sorting systems used for handling express items,cross-belt sorting systems stand out as the most ***,despite their high degree of automation,the workload for operators has intensified owing to the surging volume of express *** the era of Industry 5.0,it is imperative to adopt new technologies that not only enhance worker welfare but also improve the efficiency of cross-belt *** a balance between efficiency in handling express items and operator well-being is *** twin technology offers a promising solution in this respect.A realization method of a human-machine integrated digital twin is proposed in this study,enabling the interaction of biological human bodies,virtual human bodies,virtual equipment,and logistics equipment in a closed loop,thus setting an operating *** technologies in the proposed framework include a co.lection of heterogeneous data from multiple sources,co.struction of the relationship between operator fatigue and operation efficiency based on physiological measurements,virtual model co.struction,and an online optimization module based on real-time *** feasibility of the proposed method was verified in an express distribution center.

关键词： Industry 5.0 Cross-belt sorting system Human-machine integrated Digital twin Online optimization

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

在线全文

学校读者我要写书评

暂无评论

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 co.plete crystal forms and reduced damage to the aggregated structure during the tensile *** nucleating agent modification,the XLPE crystallisation beco.es 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