检索结果-南通市图书馆

MECHANICAl PROPERTIES OF lONGITUDINAl SUBMERGED ARC WElDED STEEl PIPES USED FOR GAS PIPElINE OF OFFSHORE OIl

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English letters) 2008年第2期21卷 85-93页

作者： z.z. Yang W. Tian Q.R. ma Y.l. li J.K. li J.z. Gao H.B. zhang Y.H. Yang Tubular Goods Research Center of CNPC Xi＇an 710065 China Xiran Aerotechnical College Xi＇an 710077 China

Since the development of offshore oil and gas, increased submarine oil and gas pipelines were installed. All the early steel pipes of submarine pipelines depended on importing because of the strict requirements of comprehensive properties, such as, anti-corrosion, resistance to pressure and so on. To research and develop domes- tic steel pipes used for the submarine pipeline, the longitudinal-seam Submerged Arc Welded （lSAW） pipes were made of steel plates cut from leveled hot rolled coils by both the JCOE and UOE （the forming process in which the plate like the letter “J”, “C”, “0” or “U” shape, then expansion） forming processes. Furthermore, the mechanical properties of the pipe base metal and weld metal were tested, and the results were in accordance with the corresponding pipe specification API SPEC 5l or DNV- OS-FI01, which showed that domestic lSAW pipes could be used for submarine oil and gas pipelines.

关键词： Mechanical properties Offshore oil and gas longitudinal-seamsubmerged arc welded pipe (lSA W) Pipeline JCOE formingprocess UOE forming process

The role of melt cooling rate on the interface between 18R and Mg matrix in Mg_(97)zn_(1)Y_(2) alloys

在线全文

学校读者我要写书评

暂无评论

Journal of magnesium and Alloys 2023年第8期11卷 2883-2890页

作者： Q.Q.Jin X.H.Shao J.M.li z.z.Peng M.lv B.zhang Y.M.li X.l.ma materials Science and Engineering Research Center Guangxi University of Science and TechnologyLiuzhou 545006China Shenyang National laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of materials Science and Engineering Hebei University of Science and TechnologyShijiazhuangHebei 050018China

The role of melt cooling rate on the interface morphology and dislocation configuration between 18R long-period stacking ordered(lPSO)structure and Mg matrix in Mg_(97)zn_(1)Y_(2)(at.%)alloys was investigated by atomic-scale HAADF-STEM *** 18R/Mg interface is step-like both in the near-equilibrium alloy and non-equilibrium *** cooling rate makes the step size more regular and *** 54R structure can be observed at the interface in the near-equilibrium alloy,and the dislocations are highly ordered.54R and 54R′structure sandwiched by b1 and b2+b3 dislocation arrays,and new dislocation configuration can be detected at the interface in the non-equilibrium alloy,but the dislocations are less ordered.18R/Mg interface containing 54R or 54R′in equilibrium width,parallel to the(010)plane,should be most stable based on elastic *** segregation of solute atoms and its strong interaction with dislocations dominate the lPSO/Mg interface via diffusion-displacive transformation.

关键词： magnesium alloys long-period stacking ordered phases Dislocations Interface structure

Effect of Rotation Rate on Microstructures and Mechanical Properties of FSW Mg-zn-Y-zr Alloy Joints

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2011年第12期27卷 1157-1164页

作者： G.M. Xie z.Y. ma z.A. luo P. Xue G.D. Wang The State Key laboratory of Rolling and Automation Northeastern University Shenyang 110819 China Shenyang National laboratory for materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China

Friction stir welding （FSW） of Mg-zn-Y-zr plates with 6 mm in thickness was successfully carried out under a wide range of rotation rates of 600-1200 r/rain with a constant traverse speed of 100 mm/min. After FSW, the coarse grains in the parent material （PM） were changed into fine equiaxed recrystallized grains at the＇nugget zone （Nz）. Furthermore, the coarse Mg-zn-Y particles （W-phase） were broken up and dispersed homogenously into the Mg matrix. With increasing rotation rates, the size of the W-phase particles at the Nz significantly decreased, but the recrystallized grain size tended to increase. The hardness values of the Nzs for all the FSW joints were higher than those of the PM, and the lowest hardness values were detected in the heat affected zone （HAz）. The fracture occurred in the thermo-mechanical affected zone （Tmaz） on the advancing side for all the FSW joints in the tensile test, due to the incompatibility of the plastic deformation between the Nz and Tmaz caused by remarkably different orientation of grains and W-phase particles. The strength of FEW ioint reaches 90% of that of its PM

关键词： Friction stir welding magnesium alloys Microstructure Mechanical property

Microscopic stresses in carbon nanotube reinforced aluminum matrix composites determined by in-situ neutron diffraction

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2020年第19期54卷 58-68页

作者： X.X.zhang J.F.zhang z.Y.liu W.M.Gan M.Hofmann H.Andrä B.l.Xiao z.Y.ma Shenyang National laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China German Engineering materials Science Centre at Mlz Helmholtz-Zentrum GeesthachtD-85747 GarchingGermany Heinz maier-leibnitz zentrum(Mlz) Technische Universität MünchenD-85747 GarchingGermany Fraunhofer Institute for Industrial mathematics Fraunhofer-Platz 1Kaiserslautern 67663Germany

One of the most desired strengthening mechanisms in the carbon nanotube reinforced aluminum matrix composites(CNT/Al)composites is the load transfer strengthening mechanism(lTSM).However,a fundamental issue concerning the lTSM is that quantitative measurements of load partitioning in these composites during loading are very *** this study,in-situ neutron diffraction study on the tensile deformation of the 3 vol.%CNT/2009 Al composite and the unreinforced 2009 Al alloy was ***{311}and{220}diffraction elastic constants(DECs)of the 2009 Al alloy were *** those DECs the average stress in the 2009 Al matrix of the composite was *** the average stress in the CNTs was separated by using the stress equilibrium *** homogenization models were also applied to explain the stress evolution in each *** results agree with experimental *** the present case,the average stress in the CNTs reaches 1630 MPa at the yield strength of the composite based on linear regression of the measured data,which leads to an increment of yield strength by about 37 *** the result of this work,an approach to quantify load partitioning in the CNTs is developed for the CNT/Al composites,which can be applied to optimize the mechanical properties of the composites.

关键词： Carbon nanotubes Aluminum matrix composites In-situ neutron diffraction load partitioning

Modulators for Terahertz Communication: The Current State of the Art

在线全文

学校读者我要写书评

暂无评论

Research 2019年第1期2019卷 895-916页

作者： z.T.ma z.X.Geng z.Y.Fan J.liu H.D.Chen College of Science Minzu University of ChinaBeijing 100081China School of Information Engineering Minzu University of ChinaBeijing 100081China State Key laboratory for Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China State Key laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China

With the increase of communication frequency,terahertz(THz)communication technology has been an important research feld;particularly the terahertz modulator is becoming one of the core devices in THz communication *** modulation performance of a THz communication system depends on the characterization of THz *** modulators based on diferent principles and materials have been studied and ***,they are still on the way to practical application due to low modulation speed,narrow bandwidth,and insufcient modulation ***,we review the research progress of THz modulator in recent years and evaluate devices critically and *** focus on the working principles such as electric,optical,optoelectrical,thermal,magnetic,programmable metamaterials and nonlinear modulation methods for THz wave with semiconductors,metamaterials,and 2D materials(such as graphene,molybdenum disulfde,and tungsten disulfde).Furthermore,we propose a guiding rule to select appropriate materials and modulation methods for specifc applications in THz communication.

关键词： modulator communication narrow

Symmetry-Protected Scattering in Non-Hermitian linear Systems

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 Physics letters 2021年第2期38卷 29-35页

作者： l.Jin z.Song School of Physics Nankai UniversityTianjin 300071China

Symmetry plays fundamental role in physics and the nature of symmetry changes in non-Hermitian *** the symmetry-protected scattering in non-Hermitian linear systems is investigated by employing the discrete symmetries that classify the random *** even-parity symmetries impose strict constraints on the scattering coefficients:the time-reversal(C and K) symmetries protect the symmetric transmission or reflection;the pseudo-Hermiticity(Q symmetry) or the inversion(P) symmetry protects the symmetric transmission and *** the inversion-combined time-reversal symmetries,the symmetric features on the transmission and reflection *** odd-parity symmetries including the particle-hole symmetry,chiral symmetry,and sublattice symmetry cannot ensure the scattering to be *** guiding principles are valid for both Hermitian and non-Hermitian linear *** findings provide fundamental insights into symmetry and scattering ranging from condensed matter physics to quantum physics and optics.

关键词： symmetry symmetric parity

Measurement, modelling, and closed-loop control of crystal shape distribution： literature review and future perspectives

在线全文

学校读者我要写书评

暂无评论

Particuology 2016年第3期14卷 1-18页

作者： Cai Y. ma Jing J. liu Xue z. Wang Institute of Particle Science and Engineering School of Chemical and Process Engineering University of Leeds Leeds 1.52 9JT United Kingdom School of Chemistry and Chemical Engineering South China University of Technology Guangzhou 510640 China

Crystal morphology is known to be of great importance to the end-use properties of crystal products, and to affect down-stream processing such as filtration and drying. However, it has been previously regarded as too challenging to achieve automatic closed-loop control. Previous work has focused on controlling the crystal size distribution, where the size of a crystal is often defined as the diameter of a sphere that has the same volume as the crystal. This paper reviews the new advances in morphological population balance models for modelling and simulating the crystal shape distribution （CShD）, measuring and estimating crystal facet growth kinetics, and two- and three-dimensional imaging for on-line characterisation of the crystal morphology and CShD. A framework is presented that integrates the various components to achieve the ultimate objective of model-based closed-loop control of the CShD. The knowledge gaps and challenges that require further research are also identified.

关键词： Crystal morphology Crystal shape distribution Morphological population balance mode3D process imaging Closed-loop control of crystal shapeCrystal facet growth kinetics

Boosted activity of Cu/SiO_(2) catalyst for furfural hydrogenation by freeze drying

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 Chemical letters 2022年第2期33卷 912-915页

作者： Hong Du Xiuyun ma Miao Jiang z.Conrad zhang Dalian National laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China State Key laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

The biomass valorization is of great importance as an alternative for the production of transport fuels and fine *** hydrogenation to furfuryl alcohol is a prevailing industrial route for the utilization of hemicellulose component of *** toxicity of the chromium species in commercial copper chromite catalyst for furfuryl alcohol production motivates the development of efficient chromium-free ***,a highly efficient silica supported copper catalyst is developed in this *** catalyst is prepared by freeze drying of a gel precursor that is synthesized by ammonia evaporation,followed by calcination and H_(2)*** catalyst exhibits higher furfural hydrogenation activity than oven dried catalyst,commercial copper chromite catalyst and a plant supplied commercial silica supported copper *** catalyst also shows good *** superior performance of the freeze dried catalyst has resulted from its developed pore structure and higher amount of Cu^(0)as well as Cu^(+)active sites.

关键词： Freeze drying Cu/SiO_(2) Furfural Furfuryl alcohol Hydrogenation

MODElING OF STATIC RECRYSTAllIzATION KINETICS OF Nb-BEARING STEElS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English letters) 2006年第4期19卷 271-278页

作者： l.Q. ma z.Y. liu S.H. Jiao X.Q. Yuan D. Wu The State Key laboratory of Rolling and Automation Northeastern UniversityShenyang 110004 China Institute of Research and Development Baosteel Co. Ltd Shanghai 201900 China

By using isothermal double hit compression tests and applying the 2% offset method, a new model was developed to predict the microstructural evolution of Nb-bearing steels at temperatures above and below the start temperature of strain-induced precipitation （Tp）. The Tp was developed as a function of true strain, initial austenite grain size and the Nb content. The activation energy of static recrystallization （Qrex） was expressed as a function of the content of different alloy elements. It was found that Nb played the most important role in increasing the value of Qrex, The microstructural observations and measurements confirmed the validity of the model developed in the present investigation.

关键词： Nb-bearing steel static recrystallization Tp (start temperature of strain-induced precipitation) activation energy