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Tensile ductility and deformation mechanisms of a nanotwinned 316L austenitic stainless steel

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Journal of Materials Science & Technology 2020年第1期36卷 65-69页

作者： y.Z.Zhang J.J.Wang n.R.Tao Sheny.ng 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 University of Chinese Academy of Sciences Beijing 100049China

A nanotwinned 316 L austenitic stainless steel was prepared by means of surface mechanical grinding *** recovery annealing,the density of dislocations decreases obviously while the average twin/matrix lamella thickness still keeps in the nanometer *** annealed nanotwinned sample exhibits a high tensile yield strength of 771 MPa and a considerate uniform elongation of 8%.TEM observations showed that accommodating more dislocations and secondary twinning inside the nanotwins contribute to the enhanced ductility and work hardening rate of the annealed nanotwinned sample.

关键词： nanotwinned Stainless steel Ductility Deformation mechanism

nanostructures and nanoprecipitates induce high strength and high electrical conductivity in a CuCrZr alloy

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Journal of Materials Science & Technology 2020年第13期47卷 18-22页

作者： Z.y.Zhang L.X.Sun n.R.Tao Sheny.ng 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 College of Materials Science and Chemical Engineering Harbin Engineering UniversityHarbin 150001China

The mixed nanostructure mainly consisting of nanotwins and nanograins was obtained in a solid solution CuCrZr alloy by means of dynamic plastic deformation at cryogenic *** subsequent aging treatments,the precipitation of Cr at nanometer scale provided further strengthening and brought substantial recovery of electrical *** aged nanostructured CuCrZr alloy exhibited a high tensile strength of 832MPa and a high electrical conductivity of 71.2%*** details of precipitation tuned by nanotwin boundaries were demonstrated in this *** combined strengthening of nanostructures and nanoprecipitates was discussed.

关键词： CuCrZr alloy nanotwins Precipitation hardening Aging Electrical conductivity

RELATIOnSHIP AMOng EVAPORATIOn FLUX OF GROUnDWATER, DEPTH OF WATER TABLE AnD nEGATIVE PRESSURE HEAD In BARE SOIL

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Journal of Hydrodynamics 2000年第4期12卷 52-58页

作者： Qian, J.Z. Zhu, X.y. Zhou, n.Q. Li, G.y. Dep. of Earth Sci. Nanjing Univ. Nanjing 210093 China

Evaporation of ground water is a part of moisture circulation in the field. And it is a main natural form in which water transmits from the ground water to the soil water and atmosphere water. According to the simulated experiments, we study the relationship among the evaporation, depth of groundwater table and negative pressure. By theoretical analysis of the experimental results, the main conclusions are drawn as follows. There are two abrupt points in every Q-H curve. The locations of the abrupt points are separately in step with the height of top of the capillary fringe and the height of maximal capillary rise in the soil section. When the depth of water table H is small, the evaporation flux of ground water is large. While the depth of water table exceeds the maximal capillary rise of media in vadose zone, the capillary rise breaks up and evaporation flux of groundwater is small. The water content ratio in ground surface tends to be zero and the surface of soil tends to be drought. These conclusions show that the maximal capillary rise of media in vadose zone is an important value in regulating rational depth of ground water to reduce the evaporation of ground water and to increase effective quantity of water resources. In the meantime, these conclusions are of important theoretical and practical significance to reduce the evaporation of ground water, to prevent and cure the salinization of soil, and to make full use of and protect water resources in the northern plains in China.

关键词： Capillarity Evaporation Soils

Timoshenko beam model for chiral materials

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Acta Mechanica Sinica 2018年第3期34卷 549-560页

作者： T.y.Ma y.n.Wang L.yuan J.S.Wang Q.H.Qin Department of Mechanics Tianjin University School of Engineering Deakin University Research School of Engineering Australian National University

natural and artificial chiral materials such as deoxyribonucleic acid （DnA）, chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton＇s principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DnA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

关键词： Timoshenko beam model Chiral material Chirality Deflection Microrotation

Atomic-scale roles of Zn element in age-hardened AlMgSiZn alloys

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Journal of Materials Science & Technology 2021年第11期70卷 105-112页

作者： n.n.Jiao y.X.Lai S.L.Chen P.Gao J.H.Chen Center for High-Resolution Electron Microscopy College of Materials Science&EngineeringHunan UniversityChangsha410082China Electron Microscopy Laboratory and International Center for Quantum Materials School of PhysicsPeking UniversityBeijing100871China

Adding alloy.ng elements to improve the performances or the manufacturing processes of Al-Mg-Si alloys has long been a serious issue in developing advanced automotive aluminum *** Zn element,among those promising ones,has demonstrated positive alloy.ng effects on Al-Mg-Si ***,the atomic-scale roles of Zn in an age-hardened Al-Mg-Si-Zn alloy have not been adequately *** atomic-resolution electron microscopy,here we report the precise locations of Zn elements in all hardening precipitates involved and their alloy.ng mechanism at the atomic scale when alloy.ng the *** results show that Zn atoms enter all the major hardening phases to occupy specific featured atomic sites of the original elements,*** Si1 and Mg2 sites in theβ’-2 phase,and modify their crystal structures,interfacial structures and morphologies in characteristic *** is revealed that for theβ’-phase,Zn atoms occupy unique atomic sites,whereas for other phases,they demonstrate similar behaviors as other additive alloy.ng elements such as Ag and Cu do.

关键词： Al-Mg-Si alloy Zn addition Precipitate Electron microscopy

nitrous oxide emission by denitrify.ng phosphorus removal culture using polyhydroxyalkanoates as carbon source

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Journal of Environmental Sciences 2012年第9期24卷 1616-1623页

作者： yan Zhou Melvin Lim Soekendro Harjono Wun Jern ng Advanced Environmental Biotechnology Center (AEBC-nEWRI) 60 Nanyang Avenue North Wing Level B2 Room O1 Nanyang Technological University 639798 Singapore Keppel Environmental Technology Centre Pte Ltd. 61 Old Toh Tuck Road 597656 Singapore Division of Environmental and Water Resources Engineering School of Civil and Environmental Engineering Nanyang Technological University 639798 Singapore

nitrous oxide （n2O） emission has been reported to be enhanced during denitrification when internally-stored compounds are used as carbon sources. However, negligible n2O emissions have been detected in the few studies where polyhydroxyalkanoates （PHA） were specifically used. This study investigated and compared the potential enhancement of n2O production, based on utilization of an internally-stored polymer and external carbon （acetate） by a denitrify.ng phosphorus removal culture. Results indicated that at relatively low chemical oxygen demand-to-nitrogen （COD/n） ratios, more nitrite was reduced to n2O in the presence of an external carbon source as compared to an internal carbon source （PHA）. At relatively higher COD/n ratios, similar n2O reduction rates were obtained in all cases regardless of the type of carbon source available. n2O reduction rates were, however, generally higher in the presence of an internal carbon source. Results from the study imply that when the presence of an external carbon source is not sufficient to support denitrification, it is likely competitively utilized by different metabolic pathways of denitrify.ng polyphosphate accumulating organisms （DPAOs） and other ordinary denitfifiers. This study also reveals that the consumption of PHA is potentially the rate-limiting step for n2O reduction during denitrification.

关键词： n2O denitrification carbon source enhanced biological phosphorus removal DPAOs PHA

RATIOnAL GEnERAL SOLUTIOnS OF HIGHER ORDER ALGEBRAIC ODES

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Journal of Systems Science & Complexity 2013年第2期26卷 261-280页

作者： HUAng yanli ng L X Chu WInKLER Franz School of Computer Science and Software Engineering Tianjin Polytechnic University Research Institute for Symbolic Computation(RISC) Johannes Kepler University Department of Mathematics Quy Nhon University

This paper generalizes the method of ng6 and Winkler （2010, 2011） for finding rational general solutions of a first order non-autonomous algebraic ordinary differential equation （AODE） to the case of a higher order AODE, provided a proper parametrization of its solution hypersurface. The authors reduce the problem of finding the rational general solution of a higher order AODE to finding the rational general solution of an associated system. The rational general solutions of the original AODE and its associated system are in computable 1-1 correspondence. The authors give necessary and sufficient conditions for the associated system to have a rational solution based on proper reparametrization of invariant algebraic space curves. The authors also relate invariant space curves to first integrals and characterize rationally solvable systems by rational first integrals.

关键词： Algebraic ODE associated system invariant algebraic space curve rational first integral rational general solution.

CO and Particle Pollution of Indoor Air in Beijing and Its Elemental Analysis

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Biomedical and Environmental Sciences 1990年第2期3卷 132-138页

作者： J.n.WAng y.ZHAng Institute of Environmental Health and Engineering Chinese Academy of Preventive Medicine Beijing China

Three representative types of houses in Beijing were selected and, in each type, smoking and nonsmoking households were compared. IP, RP. and CO concentrations in the living room and kitchen were monitored during each season. and the level of COHb in the heads of the households were measured. The study showed that indoor air pollution was rather severe, especially during winter. when paniculate concentrations markedly exceeded the standard and CO concentration was as high as 47 ppm. Indoor air pollution was closely related to the type of house, particularly to the mode of heating. In houses. of the same type, pollution improved greatly after central heating facilities were installed. Analysis of 30 elements revealed that pollution was typically caused by coal burning. aggravated by dusty wind, but high indoor Pb levels were probably due to the use of LPG for cooking. In our study the effect of cigarette smoking was sometimes masked by the severe indoor pollution. (C)1990 Academic Press, Inc.

关键词： Be In CO and Particle Pollution of Indoor Air in Beijing and Its Elemental Analysis COHb

Cytotoxic and antioxidant activities and phytochemical analysis of Smilax excelsa L. and Aegopodium podagraria L.

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Food Bioscience 2023年第2期52卷 162-169页

作者： Sezen yılmaz Sarıaltın Derya Cicek Polat Can Ozgur yalcın Department of Pharmaceutical Toxicology Faculty of PharmacyAnkara UniversityAnkaraTurkiye Department of Pharmaceutical Botany Faculty of PharmacyAnkara UniversityAnkaraTurkiye Department of Pharmaceutical Toxicology Faculty of PharmacyKaradeniz Technical UniversityTrabzonTurkiye

new curative and preventative approaches with high therapeutic efficacy and minimal side effects are needed for many forms of ***,the current study aimed to assess the cytotoxic and antioxidant capacity of Smilax excelsa and Aegopodium podagraria,which are consumed on a daily diet in the Black Sea region of Turkiye,as well as their phytochemical composition to pinpoint the compounds responsible for these *** effects of the treatments on human prostate(PC3),colorectal(HCT116),and lung(A549)carcinoma cell survival and free radical scavenging potentials were *** phenolic and flavonoid contents and significant phenolic compounds were detected and quantified by *** extracts reduced cell viability in all cancer cells in a dose-dependent manner,while the most potent cytotoxic effects were noted on PC3 *** inhibited cell growth on PC3 cells at both lower and higher concentrations(50-1000μg/mL)compared with the control(pnol extract exhibited the strongest ABTS and DPPH free radical scavenging capacities,with the IC50 values of 17.16 and 45.81μg/mL,*** highest amounts of total phenolics and flavonoids,as well as chlorogenic acid and caffeic acid,were also observed in *** methanol *** results suggest that *** and ***,along with the isolated compounds,may contribute to the treatment of prostate *** the best of our knowledge,this is the first study analyzing the impacts of these plants on PC3,HCT116,and A549 cells.

关键词： Aegopodium podagraria Smilax excelsa,antioxidant Cytotoxicity Phytochemistry