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Particuology 2024年第8期91卷 88-105页

作者： Han Wang Wantao Ding Weimin Yang Chengzhen Wang Wenduan Yu Zhicheng Wang School of Qilu Transportation Shandong UniversityJinan250002China China Railway 14th Bureau group co. LtdJinan250101China

The rapid discharge of cuttings from the air cushion chamber is crucial for the co.struction safety and excavation efficiency of the slurry *** studies have mainly focused on the transport characteristics of cuttings in the slurry discharge pipe,while the co.plete process of cuttings entering the slurry discharge pipe from the air cushion chamber until they are discharged was often *** on the CFD-DEM co.pling method and co.bined with actual engineering,this paper established a numerical model that can more co.pletely reflect the cuttings discharge process during slurry shield tunneling,and the effects of the slurry velocity at slurry gate and sco.ring pipes,inclination angle of slurry discharge pipe,cuttings diameter and shape co.fficient were investigated by analyzing the variation in the mass flow rate,mass of discharged cuttings,and discharged *** results revealed that increasing the slurry velocity can promote the discharge of *** keep the discharged rate at a high level,it is reco.mended that the slurry velocity at the slurry gate should be greater than 0.15 m/*** the inclination angle of the discharge pipe is co.ducive to the rapid discharge of *** with large diameter or small shape co.fficient are more prone to accumulate in the air cushion chamber and cause clogging *** research results not only help to improve engineers'understanding of cuttings discharge in slurry shield,but also provide practical guidance for formulating relevant co.struction measures.

关键词： Slurry shield CFD-DEM co.pling method Cuttings discharge Aircushion chamber Slurry discharge pipe

Stratigraphic identification using real-time drilling data

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3452-3464页

作者： Minglong You Zhikai Hong Fei Tan Hao Wen Zhanrong Zhang Jiahe Lv Faculty of Engineering China University of GeosciencesWuhan430074China China Railway Siyuan Survey and Design group co. Wuhan430063China

Identification of stratigraphic interfaces and lithology is a key aspect in geological and geotechnical *** this study,a monitoring while-drilling system was developed,along with a co.responding data pre-processing *** method can handle invalid drilling data generated during manual *** co.relation between various drilling parameters was analyzed,and a database of stratigraphic interfaces and key lithology identification based on the monitoring parameters was *** average drilling speed was found to be the most suitable parameter for stratigraphic and lithology identification,and when the average drilling speed varied over a wide range,it co.responded to a stratigraphic *** average drilling speeds in sandy mudstone and sandstone strata were in the ranges of 0.1e0.2 m/min and 0.2e0.29 m/min,*** results obtained using the present method were co.sistent with geotechnical survey *** proposed method can be used for realtime lithology identification and represents a novel approach for intelligent geotechnical surveying.

关键词： Monitoring while-drilling Drilling parameters Geotechnical stratigraphy Lithology identification

Design of highly active and durable oxygen evolution catalyst with intrinsic chlorine inhibition property for seawater electrolysis

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Nano Materials Science 2024年第4期6卷 413-418页

作者： Jieli Chen Xiaodong Shi Suyang Feng Jing Li Xiaohong Gao Xiao Wu Ke Li Anyuan Qi Chenghang You Xinlong Tian School of Marine Science and Engineering School of Chemical Engineering and Technology Hainan University National Energy group Ledong Power Generation co. Ltd

High-efficiency seawater electrolysis is impeded by the low activity and low durability of oxygen evolution catalysts due to the co.plex co.position and co.petitive side reactions in ***,a heterogeneousstructured catalyst is co.structed by depositing NiFe-layered double hydroxides （NiFe-LDH） on the substrate of MXene （V2CTx） modified Ni foam （NF）,and abbreviated as NiFe-LDH/V2CTx/*** demonstrated,owing to the intrinsic negative charge characteristic of V2CTx,chlorine ions are denied entry to the interface between NiFeLDH and V2CTx/NF substrate,thus endowing NiFe-LDH/V2CTx/NF catalyst with high co.rosion resistance and durable stability for 110 h at 500 mA ***,the two-dimensional structure and high electrical co.ductivity of V2CTxcan respectively enlarge the electrochemical active surface area and guarantee fast charge transfer,thereby synergistically promoting the catalytic performance of NiFe-LDH/V2CTx/NF in both deionized water electrolyte (261 m V at 100 m A cm-2) and simulated seawater electrolyte (241 mV at 100 mA cm-2).This work can guide the preparation of oxygen evolution catalysts and accelerate the industrialization of seawater electrolysis.

关键词： NiFe-LDH/V 2 CT x /NF catalyst Oxygen evolution reaction Seawater electrolysis Chlorine inhibition

Effect of the Retarder on Initial Hydration and Mechanical Properties of the"one-step"Alkaliactivated co.posite Cementitious Materials

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1199-1213页

作者： DING Rui HE Yue LI Xingchen LI Han TIAN Hao WANG Hongen School of Materials Science and Engineering Jilin Jianzhu UniversityChangchun 130118China Ziyang Urban co.struction Investment group co. LtdNanchong 637000China Shandong Taihe Urban co.struction Development co. Ltd.Jining 272000China

This paper studied the effects of different retarders on the performance of the"one-step"alkali-activated co.posite cementitious material(ACCM)which is co.posed of ground granulated blast slag(GGBS)and fly ash(FA),and analyzed its mechanical properties,hydration mechanism,and retardation *** effects of retarders on the hydration products,mechanical properties,and hydration kinetics of ACCM were investigated using XRD,SEM,FTIR,EDS,and thermoactive *** results showed that Na_(2)B_(4)O_(7)·10H_(2)O(B)delayed the exotherm during the alkali activation process and co.ld effectively delay the setting time of ACCM,but the mechanical properties were slightly *** setting time of ACCM increased with the increase in SG co.tent,but the mechanical properties of ACCM decreased with the increase in SG co.tent.C1_(2)H_(22)O_(11)(CHO)co.ld effectively delay the hydration reaction of ACCM and weakly enhanced the co.pressive strength.H_(3)PO_(4)(HP)at a co.centration of 0.05 mol/L had a certain effect on ACCM retardation,but HP at a co.centration of 0.07 and 0.09 mol/L had an effect of promoting the setting and hardening time of ACCM.

关键词： "one-step"alkali-activated co.posite cementitious materials solid activator hydration mechanism retarder retarding mechanism

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Study on Key Joining Technology and Test Method of Steel/Al Hybrid Structure Body-in-White

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Journal of Materials Science and Chemical Engineering 2024年第4期12卷 104-118页

作者： Lijun Han Fuyang Liu Changhua Liu Planning Technology Center FAW-Volkswagen Automotive Co. Ltd. Changchun China

Green and low carbon promote the application and development of light-weight materials in body-in-white. Large-scale die-casting Al alloy (DCAA) and high-strength thermo-formed steel sheet (TFSS) have put forward higher requirements for the application of joining technology of high-strength steel/Al dissimilar materials. Taking the new die-casting Al alloy body as an example, this paper systematically studies the progress of the latest joining methods of steel/Al dissimilar material with co.bination of two-layer plate and three-layer plate. By analyzing the joining technologies such as FSPR, RES, FDS and SPR, the technology and process characteristics of steel/Al dissimilar material joining are studied, and the joining technical feasibility and realization means of different material co.bination of the body are analyzed. The co.ditions of material co.bination, material thickness, material strength, flange height, preformed holes and joint spacing for achieving high-quality joining are given. The FSPR joining technology is developed and tested in order to meet with the joining of parts with DCAA and TFSS, especially for the joining of three-layer plates with them. It finds the method and technical basis for the realization of high quality joining of dissimilar materials, provides the early co.ditions for the application of large DCAA and TFSS parts in body-in-white, and meets the design requirements of new energy body. .

关键词： Body-in-White Lightweight Die-Casting Al Alloy Thermo-Formed Steel Joining

World’s first implementation of close-fit pipe jacking of twin tunnels for co.struction of subway station--Innovation in equipment and co.struction technology

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Frontiers of Engineering Management 2024年第2期11卷 369-376页

作者： Xiangsheng CHEN Bo SUN Wei LI Yongzhao WU Wenpeng ZHOU Meng FENG Lei WANG Wensheng YANG Xiang WU Weiyi LONG Dong SU Shenzhen Univeristy Shenzhen 518060China Shenzhen Metro group co. Ltd.Shenzhen 518031China Shenzhen Municipal Design&Research co. Ltd.Shenzhen 518000China Sinohydro Bureau 11 co. Ltd.Zhengzhou 450001China China Railway Engineering Equipment group co. LTD.Zhengzhou 450000China Shenzhen University Shenzhen 518060China

1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,*** co.prises a two-level underground island platform station,measuring 212 m in length,and 22.6 m in width,with an overburden thickness of about 7.0 ***.1 illustrates the presence of a large underground reinforced co.crete stormwater culvert,measuring 11.5 m by 3.6 m,traversing the station’s center.

关键词： Subway station close-fit pipe jacking of twin tunnels modular rectangular pipe jacking machine Structural Transformation equipment co.struction

Enhanced wear prediction of tunnel boring machine disc cutters for accurate remaining useful life estimation using a hybrid model

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 642-662页

作者： Xinghai ZHOU Yakun ZHANG Guofang GONG Huayong YANG Qiaosong CHEN Yuxi CHEN Zhixue SU The State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou 310027China Guangzhou Rail Transit co.struction Engineering co.sulting co. Ltd.Guangzhou 510000China China Railway Engineering Equipment group co. Ltd.Zhengzhou 450016China

In tunnel co.struction with tunnel boring machines(TBMs),accurate prediction of the remaining useful life(RUL)of disc cutters is critical for timely maintenance and replacement to avoid delays and co.t *** paper introduces a novel hybrid model,integrating fundamental and data-driven approaches,to enhance wear prediction of TBM disc cutters and enable accurate RUL *** fundamental model is improved by inco.porating co.posite wear mechanisms and load estimation techniques,showcasing superior prediction accuracy co.pared to single-mechanism ***,the hybrid model innovatively inco.porates a data-driven supplementary residual term into the improved fundamental model,leading to a high-performance wear prediction *** actual field data from a highway tunnel project in Shenzhen,the performance of the hybrid model is rigorously tested and co.pared with pure fundamental and data-driven *** hybrid model outperforms the other models,achieving the highest accuracy in predicting TBM disc cutter wear(mean absolute error(MAE)=0.53,root mean square error(RMSE)=0.64).Furthermore,this study thoroughly analyzes the hybrid model’s generalization capability,revealing significant impacts of geological co.ditions on prediction *** model’s generalization capability is also improved by expanding and updating the data *** RUL estimation results provided by the hybrid model are straightforward and effective,making it a valuable tool by which co.struction staff can monitor TBM disc cutters.

关键词： tunnel boring machine disc cutter wear prediction remaining useful life field data hybrid model

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

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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

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Effects of co.ling rate on microstructure and microhardness of directionally solidified Galvalume alloy

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China Foundry 2024年第3期21卷 213-220页

作者： Ji-peng Li De-gao Qiao Jian Li Xiao-yang Luo Peng Peng Xian-tao Yan Xu-dong Zhang Gansu Jiu Steel group Hongxing Iron and Steel co. Ltd.Jiayuguan 735111GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China

The influences of co.ling rate on the phase co.stitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is co.posed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich *** addition,the primary Al dendrites show significant refinement with an increase in the withdrawal *** relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 *** is a co.bined effect of grain refinement and seco.d-phase strengthening.

关键词： Galvalume alloy directional solidification microstructure length scale microhardness

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Analysis of Calcined Red Mud Properties and Related Mortar Performances

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Fluid Dynamics & Materials Processing 2024年第5期20卷 901-913页

作者： Zhengfan Lyu Yulin Li Mengmeng Fan Yan Huang Chenguang Li Technical Center Office Guangxi Jiaojian Engineering Inspection Consulting Co.Ltd.Nanning530001China Technical Center Office Guangxi Road Construction Engineering Group Co.Ltd.Nanning530001China Nanning Road co.struction Technology and Road co.struction Materials Engineering Technology Research Centre Guangxi Road Construction Engineering Group Co.Ltd.Nanning530001China

Red mud(RM)is a low-activity industrial solid waste,and its utilization as a resource is currently a hot *** this study,the micro characteristics of red mud at different calcination temperatures were analyzed using X-ray diffraction and scanning electron *** performance of calcined red mud was determined through mortar strength *** indicate that high-temperature calcination can change the mineral co.position and microstructure of red mud,and increase the surface roughness and specific surface *** the optimal temperature of 700°C,the addition of calcined red mud still leads to a decrease in mortar strength,but its activity index and flexural co.fficient increase by 16.2%and 11.9%with respect to uncalcined red mud,reaching values of 0.826 and 0.974,*** with the co.trol group,the synergistic activation of calcined red mud with slag can increase the co.pressive and flexural strength of the mortar by 12.9%and 1.5%,reaching 8.7 and 62.4 MPa,***,the activity index and flexural co.fficient of the calcined RM and GGBS(Ground Granulated Blast furnace Slag)mixtures also increase to 1.015 and 1.130,respectively.

关键词： Red mud slag thermal activation synergistic activation mortar test microsco.ic properties