检索结果-南通市图书馆

International Journal of Minerals,Metallurgy and materials 2015年第9期22卷 956-965页

作者： Hai-tao Jiang Qiang Kang Xiao-qian Yan National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing china railway materials technologies company limited

This article introduces an element diffusion behavior model for a titanium/steel explosive clad plate characterized by a typical curved interface during the heat-treatment process. A series of heat-treatment experiments were conducted in the temperature range from 750℃ to 950℃, and the effects of heat-treatment parameters on the microstructural evolution and diffusion behavior were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and electron-probe microanalysis. Carbon atoms within the steel matrix were observed to diffuse toward the titanium matrix and to aggregate at the bonding interface at 850℃ or lower; in contrast, when the temperature exceeded 850℃, the mutual diffusion of Ti and Fe occurred, along with the diffusion of C atoms, resulting in the for- marion of Ti-Fe intermetallics （Fe2Ti/FeTi）. The diffusion distances of C, Ti, and Fe atoms increased with increasing heating temperature and/or holding time. On the basis of this diffusion behavior, a novel diffusion model was proposed. This model considers the effects of various factors, including the curvature radius of the curved interface, the diffusion coefficient, the heating temperature, and the holding rime. The experimental results show good agreement with the calculated values. The proposed model could clearly provide a general prediction of the elements＇ diffusion at both straight and curved interfaces.

关键词： explosive bonding metal cladding diffusion models interfaces heat treatment

Phase Transformation and Its Effect on Mechanical Properties of C300 Weld Metal after Aging Treatment at Different Temperatures

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2015年第6期22卷 527-533页

作者： Shuai YANG Yun PENG Xiao-mu ZHANG Zhi-ling TIAN china railway materials technologies company limited State Key Laboratory of Advanced Steel Processes and Products Central Iron and Steel Research Institute

The influence of aging temperature on phase transformation and mechanical properties of weld metal of maraging steel （grade C300） was studied. Microstructure was analyzed by means of optical microscopy, transmission e leetron microscopy, scanning electron microscopy and energy dispersive spectrum analysis. Gibbs free energy of Nia Ti and Fez Mo at different temperature was calculated by Thermal-calc software. The microstructure of weld metal in as- welded state is martensite. The yield strength of weld metal after 430 ℃ aging process may increase to 1561 MPa from 890 MPa in as-welded state, which is ascribed to the formation of spinodal constitute and GP zones. After 480 ℃ aging process, there are great deal of NiaTi precipitates in the martensite matrix and 10% reverted austenite phase in the cellular grain boundary, and the yield strength increases to 1 801 MPa. After aging process at 580 ℃ , there are many Fe2 Mo precipitates in the martensite matrix and 30%o reverted austenite phase in the cellular grain boundary, and the yield strength is 1329 MPa, which ls the lowest among the three cases. The phase transformation may also influence the toughness. It is found that precipitates make the toughness decrease and reverted austenite increases it. The mechanism of phase transformation on strength and toughness is discussed.

关键词： maraging steell weld metal aging temperature precipitate reverted austenitel mechanical property

NUMERICAL SIMULATION OF TEMPERATURE FIELD ON FLASH BUTT WELDING FOR HIGH MANGANESE STEELS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2005年第4期18卷 547-551页

作者： B.D. Yu W.D. Song F. C. Zhang china railway Shanhaiguan Bridge Group limited company Shanhaiguan 066205 China College of materials Science and Engineering Yanshan University Qinhuangdao 066004 China

An axial symmetry finite element model coupled with electricity-thermal effect was developed to study the temperature field distribution in process of the flash butt welding （FBW） of frog highmanganese steel. The influence of temperature dependent material properties and the contact resistance were taken into account in FEM ＇simulation. Meanwhile, the lost materials due to .splutter was resolved by using birth and death element. The result of analyzing data shows that the moddel in the FBW flashing is reasonable and feasible, and can exactly simulate the temperature field distribution. The modeling provides reference for analysis of welding technologies on the temperature field of high-manganese steel in FBW.

关键词： flash butt welding (FBW) numerical simulation high manganese steel,temperature field

From rock-boring organisms to tunnel boring machines:A new rock breaking technology by bioinspiration

在线全文

学校读者我要写书评

暂无评论

Biosurface and Biotribology 2021年第4期7卷 233-238页

作者： Jing Zheng Zhixin Wu Jiahui Nie Lei Lei Zhongrong Zhou Jianbin Li Tribology Research Institute Key Laboratory of Advanced Technologies of MaterialsMinistry of EducationSouthwest Jiaotong UniversityChengduChina china railway Engineering Equipment Group Corporation limited ZhengzhouChina

The purpose of this study is to achieve better understanding of associated mechanisms and to recommend and identify new strategies to develop new rock breaking technology for Tunnel Boring Machines(TBMs).Tunnel Boring Machine tunnelling mainly depends upon the rock breakage caused by cutters moving on a rock surface in a rolling and sliding motion while under the action of thrust *** rock breaking behaviour is controlled by the mechanical interaction between the cutters and the *** to the high hardness and high abrasiveness of rock,the cutters have to work under very high thrust force and suffer heavy-load-impact and abrasive wear,causing serious wear and low rock breaking ***-boring organisms exist in nature,which achieve drilling and/or tunnelling in rocks through a tribochemical *** phenomenon is called bioerosion and the organisms are natural‘TBMs’to some *** this study,the interaction between TBM cutters and rock is presented,and current measures to improve cutter wear and rock breaking efficiency and their limitations are ***,the connotation,mechanism and typical cases of bioerosion are ***,inspired by bioerosion,a new chemically assisted rock breaking technology is proposed for TBMs.

关键词： bioerosion bioinspiration rock breaking TBM cutters wear

Key technologies and Applications of the Design and Manufacturing of Non-Circular TBMs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Engineering 2017年第6期3卷 905-914页

作者： Jianbin Li china railway Hi-Tech Industry Corporation limited Beijing 100070 China

With the rapid development of the exploitation of underground space, more and more large- or super- large-diameter tunnel-boring machines （TBMs） are being employed to construct underground space projects. At present, because conventional circular TBMs cannot completely meet the requirements of underground space exploitation regarding the cross-section and space-utilization ratio, non-circular TBMs. which are the tunneling equipment for an ideal cross-section, have become the new market growth point. This paper first presents the technical features and development status of non-circular TBMs. Next, in reference to typical projects and technological innovation, this paper investigates key techniques including shield design optimization, multi-cutterhead excavation, special-shaped segment erection, and soil conditioning in loess strata for a rectangular pipe-jacking machine and a horseshoe-shaped TBM, in order to provide a set of feasible solutions for the design, manufacture, and construction of non-circular TBMs. Relevant engineering practice shows that non-circular TBMs with customized design and manufacture have great advantages in terms of construction schedule, settlement control, and space utilization.

关键词： Non-circular TBMs Rectangular pipe-jacking machine Horseshoe-shaped TBM Underground space exploitation

Research on the intelligent supervision and operation platform of railway real estate

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High-Speed railway 2023年第2期1卷 147-152页

作者： Xiangru Lv Hui Li Beisheng Liu Institute of Computing technologies China Academy of Railway Sciences Corporation LimitedBeijing 100081China

railway real estate is the fundamental element of railway transportation production and *** management and rational utilization of railway real estate is essential for railway asset *** on the investigation of the requirements of railway real estate management and operation,combined with Beidou positioning,GIS(Geographic Information System),multi-source data fusion and other cutting-edge technologies,this paper puts forward the multi-dimensional dynamic statistical method of real estate information,the identification method of railway land occupation and the comprehensive evaluation method of real estate development and utilization potential,and build the railway real estate supervision and operation platform,design the function of the platform,so as to provide intelligent solutions for the railway real estate operation.

关键词： railway Real estate supervision GIS Beidou positioning Multi-sourcedata fusion

Research and application of key technologies for data delivery in railway engineering design based on metadata

在线全文

学校读者我要写书评

暂无评论

High-Speed railway 2024年第1期2卷 51-56页

作者： Xiangru Lyu Xunxiao Yin Kun Wang Yongwen Wei Institute of Computing technologies China Academy of Railway Sciences Corporation LimitedBeijing 100081China

In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design *** railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application *** on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application *** railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced *** platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.

关键词： railway engineering Metadata Data delivery Collaborative designplatform Design results BIM services

Stability of concentration-related self-interstitial atoms in fusion material tungsten

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第5期25卷 242-245页

作者：张红温述龙潘敏黄整赵勇刘翔谌继明 Key Laboratory of Advanced Technology of materials Superconductivity and New Energy R&D CenterSouthwest Jiao Tong University Western Superconducting technologies company limited Fusion Science of Southwestern Institute of Physics

Based on the density functional theory, we calculated the structures of the two main possible self-interstitial atoms（SIAs） as well as the migration energy of tungsten（W） atoms. It was found that the difference of the 110 and 111 formation energies is 0.05–0.3 e V. Further analysis indicated that the stability of SIAs is closely related to the concentration of the defect. When the concentration of the point defect is high, 110 SIAs are more likely to exist, 111 SIAs are the opposite. In addition, the vacancy migration probability and self-recovery zones for these SIAs were researched by making a detailed comparison. The calculation provided a new viewpoint about the stability of point defects for selfinterstitial configurations and would benefit the understanding of the control mechanism of defect behavior for this novel fusion material.

关键词： irradiation self-interstitial atoms fusion material tungsten

Automatic Road Tunnel Crack Inspection Based on Crack Area Sensing and Multiscale Semantic Segmentation

在线全文

学校读者我要写书评

暂无评论

Computers, materials & Continua 2024年第4期79卷 1679-1703页

作者： Dingping Chen Zhiheng Zhu Jinyang Fu Jilin He College of Mechanical and Electrical Engineering Central South UniversityChangsha410083China Department of Geotechnical Guangdong Hualu Transportation Technology Company LimitedGuangzhou510000China National Engineering Research Center of High-Speed railway Construction Technology Changsha410075China

The detection of crack defects on the walls of road tunnels is a crucial step in the process of ensuring travel safetyand performing routine tunnel maintenance. The automatic and accurate detection of cracks on the surface of roadtunnels is the key to improving the maintenance efficiency of road tunnels. Machine vision technology combinedwith a deep neural network model is an effective means to realize the localization and identification of crackdefects on the surface of road *** propose a complete set of automatic inspection methods for identifyingcracks on the walls of road tunnels as a solution to the problem of difficulty in identifying cracks during manualmaintenance. First, a set of equipment applied to the real-time acquisition of high-definition images of walls inroad tunnels is designed. Images of walls in road tunnels are acquired based on the designed equipment, whereimages containing crack defects are manually identified and selected. Subsequently, the training and validationsets used to construct the crack inspection model are obtained based on the acquired images, whereas the regionscontaining cracks and the pixels of the cracks are finely labeled. After that, a crack area sensing module is designedbased on the proposed you only look once version 7 model combined with coordinate attention mechanism (CAYOLOV7) network to locate the crack regions in the road tunnel surface images. Only subimages containingcracks are acquired and sent to the multiscale semantic segmentation module for extraction of the pixels to whichthe cracks belong based on the DeepLab V3+ network. The precision and recall of the crack region localizationon the surface of a road tunnel based on our proposed method are 82.4% and 93.8%, respectively. Moreover, themean intersection over union (MIoU) and pixel accuracy (PA) values for achieving pixel-level detection accuracyare 76.84% and 78.29%, respectively. The experimental results on the dataset show that our proposed two-staged

关键词： Road tunnel crack inspection crack area sensing multiscale semantic segmentation CA-YOLO V7 DeepLab V3+

Lipidome Atlas of the Developing Heart Uncovers Dynamic Membrane Lipid Attributes Underlying Cardiac Structural and Metabolic Maturation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research 2023年第3期2022卷 263-280页

作者： Huan Miao Bowen Li Zehua Wang Jinming Mu Yanlin Tian Binhua Jiang Shaohua Zhang Xia Gong Guanghou Shui Sin Man Lam State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China LipidALL technologies company limited Changzhou 213022Jiangsu ProvinceChina

Precise metabolic rewiring during heart organogenesis underlies normal cardiac ***,we utilized high-coverage,quantitative lipidomic approaches to construct lipidomic atlases of whole hearts(861 lipids;31 classes)and mitochondria(587 lipids;27 classes)across prenatal and postnatal developmental stages in *** uncovered the progressive formation of docosahexaenoyl-phospholipids and enhanced remodeling of C18:2,C20:3,and C20:4 fatty acyl moieties into cardiolipins as cardiac development progresses.A preferential flow of ceramides toward sphingomyelin biosynthesis over complex glycosphingolipid formation was also *** maSigPro and GPclust algorithms,we identified a repertoire of 448 developmentally dynamic lipids and mapped their expression patterns to a library of 550 biologically relevant developmentally dynamic *** combinatorial transcriptomics and lipidomics approaches identified Hadha,Lclat1,and Lpcat3 as candidate molecular drivers governing the dynamic remodeling of cardiolipins and phospholipids,respectively,in heart *** analyses revealed that postnatal cardiolipin remodeling in the heart constitutes a biphasic process,which first accumulates polyunsaturated C78-cardiolipins prior to tetralinoleoyl cardiolipin forming the predominant *** analyses supplemented with transmission electron microscopy imaging uncovered enhanced mitochondria–lipid droplet contacts mediated by *** combinatorial analyses of multiomics data uncovered an association between mitochondrial-resident,docosahexaenoic acid-phospholipids and messenger RNA levels of proton-transporting adenosine triphosphate synthases on inner mitochondrial membranes,which adds credence to the membrane pacemaker theory of *** current findings offer lipid-centric biological insights potentially important to understanding the molecular basis of cardiac metabolic flexibility and disease pathology.

关键词： Lipid Atlas lying