检索结果-南通市图书馆

Optimizing circumferential assembly angle of rotor parts connected by curvic couplings based on acquired tooth surface error data

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

Chinese Journal of Aeronautics 2024年第3期37卷 404-416页

作者： Huibin SUN Meng LIU Yingzhi ZHANG Chenle WEI Key Laboratory of High Performance Manufacturing for Aero Engine Ministry of Industry and Information TechnologyNorthwestern Polytechnical UniversityXi’an 710072China AECC South Industry company limited Zhuzhou 412002China

Due to the excellent self-centering and load-carrying capability,curvic couplings have been widely used in advanced aero-engine ***,curvic tooth surface errors lead to poor assembly *** physical-master-gauge-based indirect tooth surface error measurement and circumferential assembly angle optimization methods have the disadvantages of high cost and weak *** unknown tooth surface fitting mechanism is a big barrier to assembly precision prediction and ***,this work puts forward a data-driven assembly simulation and optimization approach for aero-engine rotors connected by curvic *** origin of curvic tooth surface error is deeply *** 5-axis sweep scan method,a large amount of high-precision curvic tooth surface data are acquired *** on geometric models of parts,the fitting mechanism of curvic couplings is uncovered for assembly precision simulation and prediction.A circumferential assembly angle optimization model is developed to decrease axial and radial assembly *** results show that the assembly precision can be predicted accurately and improved *** uncovering the essential principle of the assembly precision formation and proposing circumferential assembly angle optimization model,this work is meaningful for assembly quality,efficiency and economy improvement of multistage aero-engine rotors connected by curvic couplings.

关键词： Curvic couplings Tooth surface error Assembly precision Axial and radial runouts Circumferential assembly angle

Recent advancements in hydrometallurgical recycling technologies of spent lithium-ion battery cathode materials

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第3期43卷 879-899页

作者： Juan Wu Li Xiao Li Shen Jian-Jun Ran Hui Zhong Yi-Rong Zhu Han Chen College of Materials and Advanced Manufacturing Hunan University of TechnologyZhuzhou412007China School of Resources Processing and Bioengineering Central South UniversityChangsha410083China Guangdong JiaNa Energy technology company Qingyuan513000China

The rapidly increasing production of lithium-ion batteries(LIBs)and their limited service time increases the number of spent LIBs,eventually causing serious environmental issues and resource *** the perspectives of clean production and the development of the LIB industry,the effective recovery and recycling of spent LIBs require urgent *** study provides an overview of the current hydrometallurgical processes employed in the recycling of spent cathode materials,focusing on the leaching of valuable metals and their *** particular,this research reviews the various leaching systems(inorganic acid,organic acid,and ammonia)and the separation of valuable metals,and then,recommendations for subsequent study are offered in an attempt to contribute to the development of highly efficient methods for recycling spent cathode *** addition,a range of existing technologies,such as solvent extraction,chemical precipitation,electrochemical deposition,and regeneration,for the postprocessing of leaching solutions are ***,the promising technologies,existing challenges and suggestions with respect to the development of effective and environmentally friendly recycling methods for handling spent cathode materials are identified.

关键词： Spent lithium-ion batteries(LIBs) Cathode material Hydrometallurgy Leaching Recycling

Microstructure and mechanical properties of continuous drive friction welded Ti_(2)AlNb alloy under different rotational rates

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2024年第10期34卷 3221-3232页

作者： Zhi-qiang BU Xiu-ping MA Jia-yun WU Zhen LÜ Hu CHEN Jin-fu LI State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China AECC South Industry company limited Zhuzhou 412002China

Ti_(2)AlNb-based alloy was joined in a continuous drive friction welding machine under different rotational rates(500,1000 and 1500 r/min).The microstructure and mechanical properties of the joints were *** is shown that the weld zone(WZ) is fully composed of recrystallized B2 phase,and the grain size decreases with increasing rotational *** thermo-mechanically affected zone(TMAZ) suffers severe deformation during welding,due to which most of original precipitation phase is dissolved and streamlines are *** the heat affected zone(HAZ),only the fine O phase is *** as-welded joint produced using 1000 r/min has the best mechanical properties,whose strength and elongation are both close to those of the base metal,while the as-welded joint obtained using 500 r/min exhibits the worst mechanical ***-weld annealing treatment annihilates the deformation microstructure and fine O phase precipitates in the joints,consequently improving the mechanical properties *** α_(2) phase is a weakness for the mechanical performance of the joint since microcracks are apt to form in it in the tensile test.

关键词： Ti2AlNb alloy continuous drive friction welding microstructure mechanical properties

Image Processing for Denoising Using Composite Adaptive Filtering Methods Based on RMSE

在线全文

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2024年第3期14卷 660-675页

作者： Yanlu Chen Ruijie Wang Puming Zong Da Chen Control Theory and Control Engineering College of Railway Transportation Hunan University of Technology Zhuzhou China Inner Mongolia Power Group Xilingol Extra High Voltage Power Supply company Xilinhot China Inner Mongolia Power Group limited Liability company XilinGol Power Supply Branch Xilinhot China

As one of the carriers for human communication and interaction, images are prone to contamination by noise during transmission and reception, which is often uncontrollable and unknown. Therefore, how to denoise images contaminated by unknown noise has gradually become one of the research focuses. In order to achieve blind denoising and separation to restore images, this paper proposes a method for image processing based on Root Mean Square Error (RMSE) by integrating multiple filtering methods for denoising. This method includes Wavelet Filtering, Gaussian Filtering, Median Filtering, Mean Filtering, Bilateral Filtering, Adaptive Bandpass Filtering, Non-local Means Filtering and Regularization Denoising suitable for different types of noise. We can apply this method to denoise images contaminated by blind noise sources and evaluate the denoising effects using RMSE. The smaller the RMSE, the better the denoising effect. The optimal denoising result is selected through comprehensively comparing the RMSE values of all methods. Experimental results demonstrate that the proposed method effectively denoises and restores images contaminated by blind noise sources.

关键词： Blind Denoising Adaptive RMSE Image Restoratio

Trajectory optimisation in electrical discharge machining of three-dimensional curved and twisted channels

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

Chinese Journal of Aeronautics 2022年第4期35卷 473-484页

作者： Jianshe ZHAO Yicong QIU Jian YUAN Chao LIU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Laboratory of Integrated Electrical Processing Nanjing HANGPU Machinery Technology Company LimitedNanjing 210000China Military Representative Bureau of the Air Force Equipment Department in Shanghai and Military Representative Office in zhuzhou Region Zhuzhou 412002China AECC South Industry company limited Zhuzhou 412002China

Numerical control electrical discharge machining(NC EDM) is one of the most widely used machining technologies for manufacturing a closed blisk flow path, particularly for three-dimensional(3D) curved and twisted flow channels. In this process, tool electrode design and machining trajectory planning are the key factors affecting machining accessibility and efficiency. Herein, to reduce the difficulty in designing the electrode and its motion path in the closed curved and twisted channels, a heuristic search hybrid optimisation strategy based on channel grids is adopted to realise the initial electrode trajectory design search and optimised size reduction. By transferring the trajectory optimisation constraints from the complex free-form surface to numbered grids, the search is found to be more orderly and accurate. The two trajectory indicators, namely argument angle and minimum distance, are analysed separately for the optimised results of the adaptive learning particle swarm optimisation algorithm, demonstrating that they can meet the actual processing *** results of NC EDM indicate that the motion path generated by this design method can meet the machining requirements of 3D curved and twisted flow channels.

关键词： Blisk Electrical discharge machining(EDM) Electrode Objective functions Trajectory generation

Numerical analysis on thermal regime in double-loop channel inductor

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2010年第1期17卷 180-186页

作者：赵涛欧少端周孑民熊家政 School of Energy Science and Power Engineering Central South University zhuzhou Torch Industrial Furnace limited company

In order to investigate the temperature distribution, a three-dimensional finite element model （FEM） was developed to simulate the temperature regime in the channels of double-loop inductor, and the simulated results were compared with experimental data from low load trials of a 400 kW inductor. The results of numerical simulations, such as the temperature and Joule heating rate, show reasonable correlation with experimental data. The results indicate that Joule heating rate and the temperature reach the maximum at the comers and the minimum at the centre of the cross-section area. The temperature difference between the inlet and outlet is in an inverse proportion to mass transport. Joule heating rate and the temperature are directly proportional to power frequency. It is concluded that mass transport and power frequency play a critical role in determining the temperature regime and Joule heating rate, the relative permeability of the magnetic core shows no significant influence on temperature regime and Joule heating rate, when the relative permeability varies from 5 000 to 10 000.

关键词： numerical simulation inductor finite element method Joule heating rate

Near-interface oxide traps in 4H–SiC MOS structures fabricated with and without annealing in NO

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第12期26卷 560-565页

作者：孙秋杰张玉明宋庆文汤晓燕张艺蒙李诚瞻赵艳黎张义门 Key Laboratory of Wide Band Gap Semiconductor Materials and Devices School of Microelectronics Xidian University Xian 710071 China zhuzhou CRRC Times Electric company limited Zhuzhou 412001 China

Near-interface oxide traps （NIOTs） in 4H-SiC metal-oxide-semiconductor （MOS） structures fabricated with and without annealing in NO are systematically investigated in this paper. The properties of NIOTs in SiC MOS structures prepared with and without annealing in NO are studied and compared in detail. Two main categories of the NIOTs, the “slow” and “fast” NIOTs, are revealed and extracted. The densities of the “fast” NIOTs are determined to be 0.761011 cm-2 and 0.471011 cm-2 for the N2 post oxidation annealing （POA） sample and NO POA sample, respectively. The densities of “slow” NIOTs are 0.791011 cm-2 and 9.441011 cm-2 for the NO POA sample and N2 POA sample, respectively. It is found that the NO POA process only can significantly reduce “slow” NIOTs. However, it has a little effect on “fast” NIOTs. The negative and positive constant voltage stresses （CVS） reveal that electrons captured by those “slow” NIOTs and bulk oxide traps （BOTs） are hardly emitted by the constant voltage stress.

关键词： 4H-SiC MOS Near-Interface Oxide traps

Numerical analysis on Joule heating of double-loop channel induction furnaces

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2009年第5期16卷 851-856页

作者：赵涛周孑民熊家政李勇 School of Energy Science and Power Engineering Central South University zhuzhou Torch Industrial Furnace limited company

In order to investigate Joule heating power,a three-dimensional finite element model(FEM) was developed to predict Joule heating power in the channels of double-loop inductor. The simulated results were compared with experimental data from low load trials for a 400 kW inductor. The results,such as power factor and Joule heating power,show reasonable correlation with experimental data,and Joule heating rate reaches the maximum at the corners and the minimum at the centre of the cross-section area. With increasing relative permeability of iron core,length of coils,current frequency and resistivity of metal melt,the power factor and Joule heating power change. It is concluded that current frequency,the resistivity and length of the coil play a critical role in determining the power factor and Joule heating power,whereas relative permeability of the magnetic core shows no significant influence on them.

关键词： numerical simulation channel induction furnace Joule heating power factor

An adaptive stable observer for on board auxiliary inverters with online current identification strategy

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2017年第4期24卷 819-828页

作者： LI Wei LIU You-mei CHEN Te-fang DENG Jiang-ming School of Information Science and Engineering Central South University Changsha 410083 China zhuzhou Electric Locomotive limited company CRRC Zhuzhou 412001 China School of Traffic Transportation Engineering Central South University Changsha 410075 China

An adaptive stable observer with output current online identification strategy for the auxiliary inverters applied in advanced electric trains, such as high speed railway, urban rail, subway and maglev trains, is proposed. The designed observer is used to estimate the state variables, i.e. controllable duty ratio and current components in d-q-o rotary reference frame. The convergence of the observer estimation error is analyzed with consideration of uncertain level variation of input voltage at direct current(DC) side and sufficient conditions are given to prove its practical stability. Experimental results are shown to confirm the effectiveness of the proposed observer.

关键词： auxiliary inverter adaptive observer online identification Lyapunov function parameter variation