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MICROSTRUCTURE ANALySIS AND MECHANICAL PROPerTIES Of Zn-Al ALLOy ROD PRODUCED By HEATED MOLD CONTINUOUS CASTING

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Acta Metallurgica Sinica(English Letters) 2003年第3期16卷 241-248页

作者： y.Ma y.Hao f.y.yan H.J.Liu State Key Laboratory of Advanced Nonferrous Materials Lanzhou University of Science & Technology Lanzhou 730050 ChinaState Key Laboratory of Advanced Nonferrous Materials Lanzhou University of Science & Technology Lanzhou 730050 ChinaState Key Laboratory of Advanced Nonferrous Materials Lanzhou University of Science & Technology Lanzhou 730050 ChinaSchool of Mechano-Electronic EngineeringHua Qian University Quanzhou 362011China

The new technology of continuous casting by heated mold was used to produce directional solidification ZA alloy lines to eliminate the inter defects of these lines and increase their mechanical properties. The results are as follows: (1) The microstruc-ture of the ZA alloy lines is the parallel directional dendritic columnar crystal. Every dendritic crystal of eutectic alloy ZA5 was composed of many layer eutectic β and η phases. The micro structure of hypereutectic ZA alloys is primary dendritic crystal and interdendritic eutectic structure. The primary phase of ZA8 and ZA12 is β, among them, but the primary phase of ZA22 and ZA27 is a. (2) Through the test to the as-cast ZA alloy lines made in continuous casting by heated mold, it is found that the tensile strength and hardness increase greatly, but the elongation decreases. With the increase of aluminum amount from ZA 5 to ZA 12, ZA22 and ZA27, the tensile strength increases gradually. ZA27 has the best comprehensive mechanical properties in these four kinds of ZA alloys. (3) Heat treatment can decrease the dendritic segregation and improve the elongation of ZA alloy, but make their strength decrease slightly.

关键词： zinc-aluminum alloy heated mold continuous casting mechanical properties heat treatment

Magnetic interaction in the metamaterial/magnet system

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Chinese Physics B 2014年第8期23卷 537-539页

作者： M.K.Alqadi f.y.Alzoubi Department of Physics Jordan University of Science and Technology

The stability of the magnetic dipole and the metamaterial with negative permeability are investigated. Analytical expressions of the interaction force and stiffness of the magnetic line and metamaterial with negative permeability are derived. The repulsive force between the magnetic line and the metamaterial exceeds the value of the maximum force in the magnet-superconductor system.

关键词： metamaterial interaction energy negative permeability

Dislocation ordering and texture strengthening of naturally aged Al-Cu-Mg alloy

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Journal of Materials Science & Technology 2022年第23期118卷 1-14页

作者： f.Liu Z.y.Liu G.y.He L.N.Ou School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of Nonferrous Metal Materials Science and Engineering Ministry of EducationCentral South UniversityChangsha 410083China National Key Laboratory of Science and Technology on High-Strength Structural Materials Central South UniversityChangsha 410083China

Stability of grain structure,dislocation ordering and strengthening mechanisms of the naturally aged AlCu-Mg alloy after solution treatment are investigated by using optical microscope(OM),scanning electron microscope(SEM),electron back-scattered diffraction(EBSD),X-ray diffraction(XRD) and transmission electron microscope(TEM).Results show that {100},{100},{110} and {110}slip systems can be activated after solution treatment,which can promote the formation of {110}Goss *** combination effect of T-Al_(20)Cu_(2) Mn_(3) phase and Goss-oriented grains with large Taylor factor makes the solution-treated alloys display excellent stability of grain *** enhanced yield strength of the alloy is ascribed to grain-refine strengthening,dispersed particles strengthening,dislocation strengthening and texture *** coarsening of the second phase is responsible for softening of the alloy after annealing at 400 ℃+solution treatment at 475 ℃.

关键词： Al-Cu-Mg alloy Dislocation ordering Goss texture Grain structure stability Texture strengthening

Effect of drainage on CO_2, CH_4, and N_2O fluxes from aquaculture ponds during winter in a subtropical estuary of China

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Journal of Environmental Sciences 2018年第3期30卷 72-82页

作者： Ping yang Derrick y.f Lai Jia f.Huang Chuan Tong School of Geographical Sciences Fujian Normal University Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education of China Fujian Normal University Department of Geography and Resource Management and Centre for Environmental Policy and Resource ManagementThe Chinese University of Hong Kong

Aquaculture ponds are dominant features of the landscape in the coastal zone of ***,aquaculture ponds are drained during the non-culture period in ***,the effects of such drainage on the production and flux of greenhouse gases（GHGs）from aquaculture ponds are largely *** the present study,field-based research was performed to compare the GHG fluxes between one drained pond（DP,with a water depth of 0.05 m）and one undrained pond（UDP,with a water depth of 1.16 m）during one winter in the Min River estuary of southeast *** the entire study period,the mean CO2flux in the DP was（0.75±0.12）mmol/（m^2·hr）,which was significantly higher than that in the UDP of（-0.49±0.09）mmol/（m^2·hr）（p0.01）.This indicates that drainage drastically transforms aquaculture ponds from a net sink to a net source of CO2in *** CH4and N2O emissions were significantly higher in the DP compared to those in the UDP（CH4=（0.66±0.31）vs.（0.07±0.06）mmol/（m^2·hr）and N2O=（19.54±2.08）vs.（0.01±0.04）μmol/（m^2·hr））（p〈0.01）,suggesting that drainage would also significantly enhance CH4and N2O *** in environmental variables（including sediment temperature,p H,salinity,redox status,and water depth）contributed significantly to the enhanced GHG emissions following pond ***,analysis of the sustained-flux global warming and cooling potentials indicated that the combined global warming potentials of the GHG fluxes were significantly higher in the DP than in the UDP（p〈0.01）,with values of739.18 and 26.46 mg CO2-eq/（m^2·hr）,*** findings suggested that drainage of aquaculture ponds can increase the emissions of potent GHGs from the coastal zone of China to the atmosphere during winter,further aggravating the problem of global warming.

关键词： Aquaculture pond Drainage management Greenhouse gas flux Global warming Min River estuary

Comparative in vitro Study on Pure Metals(fe,Mn,Mg,Zn and W) as Biodegradable Metals

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Journal of Materials Science & Technology 2013年第7期29卷 619-627页

作者： J.Cheng B.Liu y.H.Wu y.f.Zheng Center for Biomedical Materials and Tissue Engineering Academy for Advanced Interdisciplinary StudiesPeking University State Key Laboratory for Turbulence and Complex System and Department of Materials Science and Engineering College of EngineeringPeking University

five pure metals including fe, Mn, Mg, Zn and W have been investigated on their corrosion behavior and in vitro biocompatibility by electrochemical measurement, static immersion test, contact angle measurement, cytotoxicity and hemocompatibility tests. It is found that the sequence of corrosion rate of five metals in Hank＇s solution from high to low is： Mg 〉 fe 〉 Zn 〉 Mn 〉 W. fe, Mg and W show no cytotoxicity to L929 and ECV304 cells, Mn induces significant cytotoxicity to both L929 and ECV304 cells, and Zn has almost no inhibition effect on the metabolic activities of ECV304 while largely reduces the cell viability of L929 cells. The hemolysis percentage of five pure metals is lower than 5% except for Mg and platelets adhered on Zn has been activated and pseudopodia-like structures can be observed while platelets on the other four metals keep normal.

关键词： Biodegradable metals Cytotoxicity Corrosion Biocompatibflity

Local Strain Energy Density Applied to Bainitic functionally Graded Steels Plates Under Mixed-Mode(Ⅰ+Ⅱ) Loading

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Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 164-172页

作者： H.salavati y.Alizadeh f.Berto Department of Mechanical Engineering Amirkabir University of Technology Department of Management and Engineering University of Padova

In this paper, the averaged value of the strain energy density （SED） over a control volume is used to predict the critical load of V-notched specimens made of functionally graded steels （fGSs） under mixed-mode loading. The studied fGSs contain ferritic and austenite phases in addition to bainitic layer produced by electroslag remelting. The mechanism- based strain gradient plasticity theory is used to determine the flow stress （yield stress or ultimate stress） of each layer. The young＇s modulus and the Poisson＇s ratio have been assumed to be constant, while other mechanical properties vary exponentially along the specimen width. The control volume is centered in relation to the maximum principal stress present on the notch edge and assumes a crescent shape. The points belonging to the volume perimeter are obtained numerically. In the present contribution, the effects of notch radius and notch depth on the SED and the critical load are studied. The notch radius varies from 0.2 to 2.0 mm, and the notch depth varies from 5 to 7 ram. By using the SED approach and finite element simulations, the critical load is determined, and the obtained results show a sound agreement with the experimental results.

关键词： functionally bainitic graded steel Strain energy density Mechanism-based strain gradientplasticity theory Critical load Notch radius Notch depth

Oligo(aromatic ether sulfone)-f as a Nonlinear Polarized Polymeric Material: an Experiment and DfT Study

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Chinese Journal of Structural Chemistry 2021年第3期40卷 383-393,275页

作者： GAN Dong-er ZHANG Zhang LI Qiao-Hong LI Wen-Mu Key Laboratory of Optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China

Polymeric membranes with diverse structures have attracted much attention as new materials for nonlinear optical devices. In this report, a novel oligomer of poly(aromatic ether sulfone)(OAES) has been synthesized and characterized. The electronic structure as well as linear and nonlinear optical properties has been studied by density function theory. The effect for general nonlinear optical polarizability of various condition has been further researched such as absence of side chains and introduction of phenyl substituent on side chains. The static and frequency-dependent hyperpolarizabilities of OAES and its derivatives have been calculated. This work interprets an efficient adjustment for the frequency response and the intensity of nonlinear optical polarizability can be achieved by regulating the structure of system, which provides a new potential for the application of oligomeric materials on nonlinear optical field.

关键词： DfT method NLO properties oligo(aromatic ether sulfone)-f sum-over-states method

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Effect of post-bond heat treatment on the microstructure and high temperature mechanical property of a TLP bonded γ'-strengthened co-based single crystal superalloy

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Journal of Materials Science & Technology 2021年第21期80卷 244-258页

作者： S.y.Wang y.Sun C.y.Cui X.f.Sun y.Z Zhou y.M.Ma H.L.An Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China Harbin Welding Institute China Academy of Machinery Science and TechnologyHarbin 150028China

Post-bond heat treatment(PBHT) applied to a transient liquid phase(TLP) bonding joint is an effective approach to remove the brittle borides and improve its ***,we proposed two types of PBHT strategies to obtain a TLP bonded γ'-strengthened Co-based single crystal superalloy,and the microstructural characteristics and tensile properties of the two heat treated joints were compared to identify the optimal PBHT *** evolution of the brittle boride in the joint after the PBHT was studied by using in-situ *** experimental results allowed to provide a theoretic model to quantitatively evaluate the distribution of the brittle phase after the optimal PBHT and analyze the joint fractures to understand the failure *** obtained results revealed that a post-bond solid solution treatment performed to the joint at a high temperature(over 1275℃) could decrease the area fraction of the boride from 7.2 % to 1.4 % and increase the elongation from 1.9 % to 7.8 %.This work emphasizes the relevance of solid solution temperature when a PBHT strategy is applied.

关键词： Transient liquid phase(TLP) γ'-strengthened co-based single crystal superalloy Heat treatment sequence Brittle boride Tensile property

Photovoltaic enhancement of Si solar cells by assembled carbon nanotubes

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Nano-Micro Letters 2010年第1期2卷 22-25页

作者： y.f.Zhang y.f.Wang N.Chen y.y.Wang y.Z.Zhang Z.H.Zhou L.M.Wei Key laboratory for Thin film and Microfabrication of the Ministry of Education National Key Laboratory of Nano/Micro Fabrication Technology Research Institute of Micro/Nano Science and Technology Shanghai Jiao Tong University

Photovoltaic conversion was enhanced by directly assemble of a network of single-walled carbon nanotubes(SWNTs) onto the surface of n-p junction silicon solar cells. When the density of SWNTs increased from 50 to 400 tubes μm^(-2), an enhancement of 3.92% in energy conversion efficiency was typically obtained. The effect of the SWNTs network is proposed for trapping incident photons and assisting electronic transportation at the interface of silicon solar cells.

关键词： Solar cell Carbon nanotube Photovoltaic enhancement Heterojunction