检索结果-南通市图书馆

Probabilistic model of disc-cutter wear in TBM construction:A case study of Chaoer to Xiliao water conveyance tunnel in China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第12期66卷 3534-3548页

作者： YANG WenKun CHEN ZuYu wu genSheng XING hai School of Civil Engineering Institute of Future Underground SpaceSoutheast UniversityNanjing 211189China Department of geotechnical Engineering China Institute of Water Resources and Hydropower ResearchBeijing 100038China Sinohydro Bureau 6 Co. Ltd.Shenyang 110179China

Disc-cutters play a crucial role in the penetration process during construction using a tunnel boring machine(TBM).Their wear status has a significant impact on working efficiency and costs that accounts for a large part of the *** the wear pattern and characteristics of disc-cutters could provide a valuable guide for field maintenance and cutter replacement *** also provides insight into the wear mechanism of cutters at different positions for optimizing the disc-cutter arrangement *** this study,the cutter wears data of 34 disc-cutters over 643 days in the Chaoer River to Xiliao River water diversion tunnel was *** dataset contains 21862 manual readings measured from 1079 disc-cutters replaced in this *** raw data from the hard copy version was transformed into a digital twin database by eliminating abnormal data,filling in empty values,and performing linear *** has been found that the cutters can pass statistical testing for an exponential probability distribution function with respect to the wear rate(w).The regression ratios of R2are essentially greater than *** findings would help estimate the future service life of a currently working cutter,which means significant savings for the costly *** application of exponential distribution has the advantage of only one shape parameter,λ,whose reciprocal represents both the statistical mean and standard deviation of the wear *** is simple and practically amenable.A preliminary study was carried out to simulate the wear process between two neighboring cutters for drafting a replacement plan for disc-cutters by the Monte Carlo *** prediction results agreed reasonably well with the measured information.

关键词： tunnel boring machine disc-cutter wear wear rate probability model

Attack-Resilient Distributed Cooperative Control of Virtually Coupled High-Speed Trains via Topology Reconfiguration

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1066-1068页

作者： Shunyuan Xiao Xiaohua ge Qing wu the Institute of Advanced Technology Nanjing University of Posts and TelecommunicationsNanjing 210023China the School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyMelbourne VIC 3122Australia the School of Engineering and Technology Central Queensland UniversityRockhampton QLD 4701Australia

Dear Editor,This letter addresses the resilient distributed cooperative control problem of a virtually coupled train convoy under stochastic disturbances and cyber *** main purpose is to achieve distributed coordinati... 详细信息

关键词： prescribed Speed trains

Probing the catalytic activity of M-N_(4−x)O_(x) embedded graphene for the oxygen reduction reaction by density functional theory

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2021年第5期15卷 1206-1216页

作者： Fan ge Qingan Qiao Xin Chen You wu State Key Laboratory of Oil and Gas Reservoir geology and Exploitation Southwest Petroleum UniversityChengdu610500China School of Chemistry and Materials Science Ludong UniversityYantai264025China Center for Computational Chemistry and Molecular Simulation College of Chemistry and Chemical EngineeringSouthwest Petroleum UniversityChengdu610500China Oil&Gas Field Applied Chemistry Key Laboratory of Sichuan Province College of Chemistry and Chemical EngineeringSouthwest Petroleum UniversityChengdu610500China

In this work,the detailed oxygen reduction reaction(ORR)catalytic performance of M-N_(4−x)O_(x)(M=Fe,Co,and Ni;x=1−4)has been explored via the detailed density functional theory *** results suggest that the formation energy of M-N_(4−x)O_(x)shows a good linear relationship with the number of doped O *** adsorption manner of O_(2)on M-N_(4−x)O_(x)changed from end-on(x=1 and 2)to side-on(x=3 and 4),and the adsorption strength gradually *** on the results for binding strength of ORR intermediates and the Gibbs free energy of ORR steps on the studied catalysts,we screened out two highly active ORR catalysts,namely Co-N_(3)O_(1)and Ni-N_(2)O_(2),which possess very small overpotentials of 0.27 and 0.32 V,*** activities are higher than the precious Pt *** structure analysis reveals one of the reasons for the higher activity of Co-N_(3)O_(1)and Ni-N_(2)O_(2)is that they have small energy gaps and moderate highest occupied molecular orbital energy ***,the results of the density of states reveal that the O doping can improve the electronic structure of the original catalyst to tune the adsorption of the ORR intermediates.

关键词： M-N-C catalyst oxygen doping oxygen reduction reaction catalytic activity density functional theory

Recent progress and perspectives on silicon anode:Synthesis and prelithiation for LIBs energy storage

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2022年第1期31卷 615-650,I0016页

作者： Yuanxing Zhang Borong wu ge Mu Chengwei Ma Daobin Mu Feng wu School of Materials Science and Engineering Beijing Institute of TechnologyBeijing Key Laboratory of Environment Science and EngineeringBeijing 100081China Collaborative Innovation Center of Electric Vehicles in Beijing Beijing 100081China

The ever-increasing environmental/energy crisis as well as the rapid upgrading of mobile devices had stimulated intensive research attention on promising alternative energy storage and conversion *** these devices,alkali metal ion batteries,such as lithium-ion batteries(LIBs) had attracted increasing research attention due to its several advantages including,environmental friendliness,high power density,long cycle life and excellent *** had been widely used in consumer electronics,electric vehicles,and large power grids et ***-based(silicon and their oxides,carbides) anodes had been widely *** several advantages including low cost,high theoretical capacity,natural abundance,and environmental friendliness,which shows great potential as anodes of *** this review,we summarized the recently progress in the synthetic method of silicon matrix *** empirical method for prelithiation of silicon-based materials were also ***,we also reviewed some novel characterization ***,the new design,preparation methods and properties of these nano materials were reviewed and *** hoped that this review can provide a general overview of recent progress and we briefly highlighted the current challenges and prospects,and will clarify the future trend of silicon anode LIBs research.

关键词： Si anodes Lithium-ion batteries Prelithiation Characterization Energy storage and conversion

Cutting force prediction for circular end milling process

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2013年第4期26卷 1057-1063页

作者： wu Baohai Yan Xue Luo Ming Gao ge Key Laboratory of Contemporary Design and Integrated Manufacturing Technology Ministry of Education Northwestern Polytechnical University AVIC Commercial Aircraft Engine Co. Ltd.

A deduced cutting force prediction model for circular end milling process is presented in this paper. Traditional researches on cutting force model usually focus on linear milling process which does not meet other cutting conditions, especially for circular milling process. This paper presents an improved cutting force model for circular end milling process based on the typical linear milling force model. The curvature effects of tool path on chip thickness as well as entry and exit angles are analyzed, and the cutting force model of linear milling process is then corrected to fit circular end milling processes. Instantaneous cutting forces during circular end milling process are predicted according to the proposed model. The deduced cutting force model can be used for both linear and circular end milling processes. Finally, circular end milling experiments with constant and variable radial depth were carried out to verify the availability of the proposed method. Experiment results show that measured results and simulated results corresponds well with each other.

关键词： Chip thickness Circular end milling Cutting force Machining Radial depth Tool path curvature

Influence of bath composition on the electrodeposition of cobalt-molybdenum amorphous alloy thin films

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2008年第5期15卷 611-617页

作者： Qiaoying Zhou Hongliang ge Guoying Wei Qiong wu College of Science China Jiliang University Hangzhou 310018 China

Cobalt-molybdenum （Co-Mo） amorphous alloy thin films were deposited on copper substrates by the electrochemical method at pH 4.0. Among the experimental electrodeposition parameters,only the concentration ratio of molybdate to cobalt ions （[MoO4^2-]/[Co^2＋]） was varied to analyze its influence on the mechanism of induced cobalt-molybdenum codeposition. Voltammetry was one of the main techniques,which was used to examine the voltammetric response,revealing that cobalt-molybdenum codeposition depended on the nature of the species in solution. To correlate the type of the film to the electrochemical response,various cobalt-molybdenum alloy thin films obtained from different [MoO4^2-]/[Co^2＋] solutions were tested. Crack-free homogeneous films could be easily obtained from the low molybdate concentrations （[MoO4^2-]/[Co^2＋]≈0.05） applying low deposition potentials. Moreover,the content of molybdenum up to 30wt% could be obtained from high molybdate concentration; in this case,the films showed cracks. The formation of these cracked films could be predicted from the observed distortions in the curves of electric current-time （j-t） deposition transients. The films with amorphous structure were obtained. The hysteresis loops suggested that the easily magnetized axis was parallel to the surface of the films. A saturation magnetization of 137 emu·g^-1 and a coercivity of 87 Oe of the film were obtained when the deposition potential was -1025mV,and [ MoO4^2-]/[Co^2＋] was 0.05 in solution,which exhibited a nicer soft-magnetic response.

关键词： Co-Mo alloy thin films amorphous electrodeposition soft magnetism

A sludge volume index (SVI) model based on the multivariate local quadratic polynomial regression method

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第5期26卷 1071-1077页

作者： Honggui Han Xiaolong wu Luming ge Junfei Qiao College of Automation Faculty of Information Technology Beijing University of Technology Beijing 100124 China Beijing Key Laboratory of Computational Intelligence and Intelligent System Beijing 100124 China

In this study, a multivariate local quadratic polynomial regression(MLQPR) method is proposed to design a model for the sludge volume index(SVI). In MLQPR, a quadratic polynomial regression function is established to describe the relationship between SVI and the relative variables, and the important terms of the quadratic polynomial regression function are determined by the significant test of the corresponding coefficients. Moreover, a local estimation method is introduced to adjust the weights of the quadratic polynomial regression function to improve the model accuracy. Finally, the proposed method is applied to predict the SVI values in a real wastewater treatment process(WWTP). The experimental results demonstrate that the proposed MLQPR method has faster testing speed and more accurate results than some existing methods.

关键词： Sludge volume index Multivariate quadratic polynomial regression Local estimation method Wastewater treatment process

Effects of tension on vortex-induced vibration(ⅥⅤ) responses of a long tensioned cylinder in uniform flows

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2017年第1期33卷 1-9页

作者： Ling Kang Fei ge Xiaodong wu Youshi Hong Institute of Mechanics Chinese Academy of SciencesNo. 15 Beisihuan Xi Road Beijing 100190 China

The effects of tension on vortex-induced vibration (VIV) responses for a tension-dominated long cylinder with an aspect ratio of 550 in uniform flows are experimentally investigated in this paper. The results show that elevated tension suppresses fluctuations of maximum displacement with respect to flow velocity and makes chaotic VIV more likely to appear. With respect to periodic VIV, if elevated tension is applied, the dominant vibration frequency in the in-line (IL) direction will switch from a fundamental vibration frequency to twice the value of the fundamental vibration frequency, which results in a ratio of the dominant vibration frequency in the IL direction to that in the cross-flow direction of 2.0. The suppression of the elevated tension in the fluctuation of the maximum displacement causes the axial tension to become an active control parameter for the VIV maximum displacement of a tension-dominated long riser or tether of an engineering structure in deep oceans. However, the axial tension must be optimized before being used since the high dominant vibration frequency due to the elevated tension may unfavorably affect the fatigue life of the riser or tether.

关键词： Tension effect Maximum displacement Dominant vibration frequency Chaos

Optimization of the power, efficiency and ecological function for an air-standard irreversible Dual-Miller cycle

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2019年第3期13卷 579-589页

作者： Zhixiang wu Lingen CHEN Yanlin ge Fengrui SUN Institute of Thermal Science and Power Engineering Naval University of EngineeringWuhan 430033China Military Key Laboratory for Naval Ship Power Engineering Naval University of EngineeringWuhan 430033China College of Power Engineering Naval University of EngineeringWuhan 430033China

This paper establishes an irreversible DualMiller cycle (DMC) model with the heat transfer (HT) loss, friction loss (FL) and other internal irreversible losses. To analyze the effects of the cut-off ratio (ρ) and Miller cycle ratio (rM) on the power output (P), thermal efficiency (η) and ecological function (E), obtain the optimal popt and optimal rMopt, and compare the performance characteristics of DMC with its simplified cycles and with different optimization objective functions, the P,η and E of irreversible DMC are analyzed and optimized by applying the finite time thermodynamic (FTT) theory. Expressions of P,η and E are derived. The relationships among P,η, E and compression ratio (ε) are obtained by numerical examples. The effects of ρ and rM on P,η, E, maximum power output (MP), maximum efficiency (MEF) and maximum ecological function (ME) are analyzed. Performance differences among the DMC, the Otto cycle (OC), the Dual cycle (DDC), and the Otto-Miller cycle (OMC) are compared for fixed design parameters. Performance characteristics of irreversible DMC with the choice of P,η and E as optimization objective functions are analyzed and compared. The results show that the irreversible DMC engine can reach a twice-maximum power, a twicemaximum efficiency, and a twice-maximum ecological fiinction, respectively. Moreover, when choosing E as the optimization objective, there is a 5.2% of improvement in η while there is a drop of only 2.7% in P compared to choosing P as the optimization objective. However, there is a 5.6% of improvement in P while there is a drop of only 1.3% in rj compared to choosing as the optimization objective.

关键词： finite-time thermodynamics Dual-Miller cycle power output thermal efficiency ecological function