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TOTAL ENERGIES AND ELECTRONIC STRUCTURES OF CO_3Ti AND HYDROGENIZED Co_3Ti

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Acta Metallurgica Sinica(English Letters) 1998年第3期11卷 197-201页

作者： S.q.duan S.J.Liu B.K.Ma Beijing Normal Univ Beijing China

Electronic structure calculations using the tighting-binding linear muffin-tin orbital (TB-LMTO) method have been performed for Co3Ti and its hydride CO3Ti. The computed values of lattice constants and bulk moduli agree with the experiment values. The theoritical excess enerpy and lattice staid due to hydrogen absorption consequently obtained hem the ab initio results indicate that H has the tendency to stay in Co3Ti and the ionicities of Co atomic spheres due to hydmpen absorption change from the canons to the ations. On the other hand, the changes of band structures due to hydrogenation are found to be remarkable.

关键词： total enerpy electronic structure hydrogenized Co3Ti

Experimental studies on gas and water permeability of fault rocks from the rupture of the 2008 Wenchuan earthquake, China

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Science China Earth Sciences 2014年第10期57卷 2825-2834页

作者： duan qingBao YANG XiaoSong State Key Laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration

The permeabilities of fault rocks from the rupture of Wenchuan earthquake were measured by using nitrogen gas and distilled water as pore fluids under the confining pressure ranging from 20 to 180 MPa at room temperature. Experimental results indi- cate that both gas and water permeabilities decrease with increasing confining pressure, described by power law relationship, i.e., b = 0.2x10-3kl-0.557. The water permeability is about one order less than gas permeability and also half order smaller than the permeability corrected by the Klinkenberg effect, so-called intrinsic permeability. The differences in the permeabilies imply that the reduction of effective pore size caused by the adhesion of water molecules to clay particle surface and water-swelling of expandable clay minerals contributes to lessening the water permeability besides the Klinkenberg effect. Hence, the liquid permeability of fault rocks cannot be deduced by gas permeability by the Klinkenberg correction reliably and accurately, and it is necessary to use liquid as pore media to measure their transport property directly.

关键词： fault rocks permeability Klinkenberg effect pore pressure oscillation method rupture of Wenchuan earthquake

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Hardness-thermal stability synergy in nanograined Ni and Ni alloys:Superposition of nanotwin and low-energy columnar boundary

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Journal of Materials Science & Technology 2023年第6期137卷 123-131页

作者： F.H.duan Y.Lin q.Li J.H.Luan J.Lu J.Pan Y.Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Laboratory of Nanomaterials&Nanomechanics Department of Mechanical EngineeringCity University of Hong KongHong KongChina State Key Laboratory of Material Processing and Die&Mould Technology and School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Department of Materials Science and Engineering City University of Hong KongHong KongChina Centre for Advanced Structural Materials Greater Bay Joint DivisionShenyang National Laboratory for Materials ScienceCity University of Hong Kong Shenzhen Research InstituteShenzhen 518057China City U-Shenzhen Futian Research Institute Shenzhen 518045China

Refining grains into nanoscale can significantly strengthen and harden metallic materials;however,nanograined metals generally exhibit low thermal stability,hindering their practical *** this work,we exploit the superposition of the contribution of nanotwins,low-angle grain boundaries,and microalloying to tailor superior combinations of high hardness and good thermal stability in Ni and Ni *** the nanotwinned Ni having a twin thickness of∼2.9 nm and grain size of 28 nm,it exhibits a hardness over 8.0 GPa and an onset coarsening temperature of 623 K,both of which are well above those of nanograined ***/Mo microalloying can further improve the onset coarsening temperature to 773 K without comprising *** analyses reveal that high hardness is achieved via strengthen-ing offered by extremely fine ***,the superior thermal stability is mainly ascribed to the low driving force for grain growth induced by the low-angle columnar boundary architecture and to the additional pinning effect on the migration of twin/columnar boundaries provided by minor Re/Mo *** present work not only reveals a family of nanotwinned metals possessing the combination of ultra-high hardness and high thermal stability but also provides a strategy for tailoring properties of metallic materials by pairing low-angle grain boundaries and twin boundaries.

关键词： Nanotwin Thermal stability Hardness Low-angle grain boundary Microalloying

Enhancing strength and ductility in the nugget zone of friction stir welded 7Mn steel via tailoring austenitic stability

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Journal of Materials Science & Technology 2024年第18期185卷 174-185页

作者： Y.q.Wang F.Y.Li J.X.Su R.H.duan Z.A.Luo G.M.Xie State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

The martensite often appears in the nugget zone(NZ)of friction stir welding(FSW)7 wt.%Mn steel due to low austenite stability,deteriorating ductility and *** this work,a 7 wt.%Mn steel was sub-jected to FSW,and preheating was used to tailor the austenitic stability to greatly improve the strength-ductility combination of the *** austenitic deformation behavior and strain hardening mechanism in the NZ were systematically *** microstructure of the as-welded NZ was composed of ultrafine blocky ferrite,austenite,and small amounts of martensite,whereas the as-preheated NZ con-tained ultrafine blocky ferrite and austenite,and the concentration of Mn in austenite was increased from 8.4 wt.%to 10.7 wt.%.This enhanced the austenitic stability,resulting in a significant increase in the volume fraction of austenite in the as-preheated NZ from 37.3%to 66.4%.The product of strength and elongation(PSE)in the as-preheated NZ increased dramatically from 42.6 GPa%to 67.1 GPa%,depending on a persistent high strain hardening rate(SHR).Multiple strain-hardening mechanisms were *** austenite with enhanced stability can provoke sustained transformation-induced plasticity(TRIP)and twinning-induced plasticity(TWIP)effects,and massive dislocation multiplication occurs during tension,resulting in strong strain hardening.

关键词： Friction stir welding Medium Mn steel Preheating Transformation-induced plasticity Twinning-induced plasticity

Unexpected creep behavior in a rejuvenated metallic glass

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Journal of Materials Science & Technology 2023年第32期163卷 140-149页

作者： J.P.Wu Y.Lin F.H.duan q.Chen H.T.Wang N.Li J.L.Wen J.Pan L.Liu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Material Processing and Die&Mould Technology and School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Laboratory of Nanomaterials&Nanomechanics Department of Mechanical EngineeringCity University of Hong KongHong KongChina Wuhan National High Magnetic Field Center Huazhong University of Science and TechnologyWuhan 430074China Shenzhen Polytechnic Shenzhen 518055China

Rejuvenation,bringing metallic glasses(MGs)to the younger and higher energy states,provides an alternative avenue to explore the interplay between the property and microstructures of *** this study,the creep behavior of the Zr_(69.5)Cu_(12)Ni_(11)Al_(7.5)MGs was experimentally examined by controlling the energy state in terms of structural rejuvenation and thermal *** is found that compared to the as-cast counterpart,the annealed MG at a lower energy state exhibits a higher hardness,a smaller displacement,and a lower creep rate due to the decreased free volume and the inhibited activation of the shear transformation ***,the rejuvenated MG at a high energy state displays lower hardness and increased free volume content,yet it demonstrates superior creep resistance compared to its as-cast counterpart,which deviates from conventional *** unexpected phenomenon occurs as the initial high-content free volume annihilates during creep,and strain hardening takes precedence over strain softening as the prevailing process during creep deformation,leading to a superior creep performance in extremely rejuvenated MGs.

关键词： Metallic glass Energy state Rejuvenation Creep Strain-hardening

PERSPECTIVES IN MECHANICS OF HETEROGENEOUS SOLIDS

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Acta Mechanica Solida Sinica 2011年第1期24卷 1-26页

作者： C.q. Chen J.Z. Cui H.L. duan X.q. Feng L.H. He G.K. Hu M.J. Huang Y.Z. Huo B.H. Ji B. Liu X.H. Peng H.J. Shi q.P. Sun J.X. Wang Y.S. Wang H.P. Zhao Y.P. Zhao q.S. Zheng W.N. Zou Department of Engineering Mechanics AML Tsinghua University Beijing 100084 China Academy of Mathematics and Systems Sciences Chinese Academy of Sciences Beijing 100190 China State Key Laboratory for Turbulence and Complex System and Department of Mechanics and Aerospace Engineering College of Engineering Peking University Beijing 100871 China CAS Key Laboratory of Mechanical Behavior and Design of Materials University of Science and Technology of China Hefei Anhui 230026 China School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 China Institute for Advanced Study Nanchang University Nanchang 330031 China Depariment of Mechanics and Engineering Sciences Fudan University 220 Handa Road Shanghai 200433 China Department of Mechanical Engineering Hong Kong University of Science and Technology Hong KongChina Department of Mechanical Engineering Hong Kong University of Science and Technology Hong Kong China Institute of Engineering Mechanics Beijing Jiaotong University Beijing 100044 China State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

The Micro- and Nano-mechanics Working Group of the Chinese Society of Theoretical and Applied Mechanics organized a forum to discuss the perspectives, trends, and directions in mechanics of heterogeneous materials in January 2010. The international journal, Acta Mechanica Solida Sinica, is de- voted to all fields of solid mechanics and relevant disciplines in science, technology, and engineering, with a balanced coverage on analytical, experimental, numerical and applied investigations. On the occasion of the 30TM anniversary of Acta Mechanica Solida Sinica, its editor-in-chief, Professor q.S. Zheng invited some of the forum participants to review the state-of-the-art of mechanics of heterogeneous solids, with a particular emphasis on the recent research development results of Chinese scientists. Their reviews are organized into five research areas as reported in different sections of this paper. ~I firstly brings in fo- cus on micro- and nano-mechanics, with regards to several selective topics, including multiscale coupled models and computational methods, nanocrystal superlattices, surface effects, micromechanical damage mechanics, and microstructural evolution of metals and shape memory alloys. ~II shows discussions on multifield coupled mechanical phenomena, e.g., multi-fields actuations of liquid crystal polymer networks, mechanical behavior of materials under radiations, and micromechanics of heterogeneous materials. In ~III, we mainly address the multiscale mechanics of biological nanocomposites, biological adhesive surface mechanics, wetting and dewetting phenomena on microstructured solid surfaces. The phononic crystals and manipulation of elastic waves were elaborated in ~IV. Finally, we conclude with a series of perspectives on solid mechanics. This review will set a primary goal of future science research and engineering application on solid mechanics with the effort of social and economic development.

关键词： heterogeneous materials smart materials biological materials multiscale mechanics micro- and nano-mechanics damage and fracture constitutive relation elastic wave surface effects

Genome-wide distribution and functions of the AAE complex in epigenetic regulation in Arabidopsis

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Journal of Integrative Plant Biology 2021年第4期63卷 707-722页

作者： Yi-Zhe Zhang Juncheng Lin Zhizhong Ren Chun-Xiang Chen Daisuke Miki Si-Si Xie Jian Zhang Ya-Nan Chang Jing Jiang Jun Yan qingshun q.Li Jian-Kang Zhu Cheng-Guo duan Shanghai Center for Plant Stress Biology and CAS Center of Excellence for Molecular Plant Sciences Chinese Academy of SciencesShanghai 201602China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems College of the Environment and EcologyXiamen UniversityXiamen 361102China State Key Laboratory of Crop Stress Adaptation and Improvement School of Life SciencesHenan UniversityKaifeng 475004China School of Life Sciences East China Normal UniversityShanghai 200241China Graduate College of Biomedical Sciences Western University of Health SciencesPomona 91766USA Department of Horticulture and Landscape Architecture Purdue UniversityWest Lafayette 47907USA

Heterochromatin is widespread in eukaryotic genomes and has diverse impacts depending on its genomic *** studies have shown that a protein complex,the ASI1-AIPP1-EDM2(AAE)complex,participates in polyadenylation regulation of several intronic heterochromatin-containing ***,the genome-wide functions of AAE are still ***,we show that the ASI1 and EDM2 mostly target the common genomic regions on a genome-wide level and preferentially interacts with genetic ***(poly(A)sequencing reveals that AAE complex has a substantial influence on poly(A)site usage of heterochromatin-containing genes,includingnotonlyintronicheterochromatincontaining genes but also the genes showing overlap with ***,AAE is also involved in the alternative splicing regulation of a number of heterochromatin-overlapping genes,such as the disease resistance gene *** provided evidence that genic heterochromatin is indispensable for the recruitment of AAE in polyadenylation and splicing *** addition to conferring RNA processing regulation at genic heterochromatin-containing genes,AAE also targets some transposable elements(TEs)outside of genes(including TEs sandwiched by genes and island TEs)for epigenetic *** results reveal new functions of AAE in RNA processing and epigenetic silencing,and thus representimportantadvancesinepigenetic regulation.

关键词： alternative polyadenylation alternative splicing epigenetic regulation heterochromatin transcription

In situ neutron diffraction unravels deformation mechanisms of a strong and ductile Fe Cr Ni medium entropy alloy

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Journal of Materials Science & Technology 2022年第21期116卷 103-120页

作者： L.Tang F.q.Jiang J.S.Wróbel B.Liu S.Kabra R.X.duan J.H.Luan Z.B.Jiao M.M.Attallah D.Nguyen-Manh B.Cai School of Metallurgy and Materials University of BirminghamB152TTUnited Kingdom Institute of Metal Research Chinese Academy of SciencesShenyang 110016China Faculty of Materials Science and Engineering Warsaw University of Technologyul.Wołoska 141Warsaw 02-507Poland State Key Laboratory for Powder Metallurgy Central South UniversityChangsha 410083China Rutherford Appleton Laboratory ISIS FacilityDidcot OX110QXUnited Kingdom Department of Materials Science and Engineering City University of Hong KongKowloonHong KongChina Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHung HomHong KongChina CCFE United Kingdom Atomic Energy AuthorityAbingdonOxfordshire OX143DBUnited Kingdom

We investigated the mechanical and microstructural responses of a high-strength equal-molar medium entropy FeCrNi alloy at 293 and 15 K by in situ neutron diffraction *** 293 K,the alloy had a very high yield strength of 651±12 MPa,with a total elongation of 48%±5%.At 15 K,the yield strength increased to 1092±22 MPa,but the total elongation dropped to 18%±1%.Via analyzing the neutron diffraction data,we determined the lattice strain evolution,single-crystal elastic constants,stacking fault probability,and estimated stacking fault energy of the alloy at both temperatures,which are the critical parameters to feed into and compare against our first-principles calculations and dislocation-based slip system *** density functional theory calculations show that the alloy tends to form shortrange order at room ***,atom probe tomography and atomic-resolution transmission electron microscopy did not clearly identify the short-range ***,at 293 K,experimental measured single-crystal elastic constants did not agree with those determined by first-principles calculations with short-range order but agreed well with the values from the calculation with the disordered configuration at 2000 *** suggests that the alloy is at a metastable state resulted from the fabrication *** view of the high yield strength of the alloy,we calculated the strengthening contribution to the yield strength from grain boundaries,dislocations,and lattice *** lattice distortion contribution was based on the Varenne-Luque-Curtine strengthening theory for multi-component alloys,which was found to be 316 MPa at 293 K and increased to 629 MPa at 15 K,making a significant contribution to the high yield *** plastic deformation,dislocation movement and multiplication were found to be the dominant hardening mechanism at both temperatures,whereas twinning and phase transformation were not *** is mainly due to the high stack

关键词： Medium entropy alloy Multi-component alloy Cryogenic temperature Neutron diffraction

Examining the association between apparent temperature andadmissions for schizophrenia in Hefei,China,2005–2014:A time-series analysis

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Examining the association between apparent temperature andad...