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Photoproduction of multi-meson final states–recent results from the Crystal-Barrel/TAPS experiment at ELSA-

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Chinese Physics C 2009年第12期33卷 1105-1112页

作者： u. Thoma HISkP Universitt Bonn Nussallee 14-16 53115 Bonn Germany

Multi-meson final states such as γp →pπ0π0 and γp →pπ0η have been investigated with the Crystal-Barrel/TAPS experiment at ELSA. Baryon cascades via △π and △η and also via higher mass baryon resonances are clearly observed. Based on this data and on data from other reactions a partial wave analysis has been performed from which partial decay widths of various N＊ and △＊ states into the different pπ0π0 and pπ0η decay channels have been determined, leading partly to unexpected results. In addition, polarisation observables have been investigated. The beam asymmetry X has been determined for both reactions and double polarisation data using a longitudinally polarised target and a circularly or linearly polarised photon beam has been taken. Given the angular coverage of the Crystal-Baxrel/TAPS experiment this data covers almost the full angular range and phase space. This data will provide new and important information for the partial wave analyses and bring us one step closer towards a complete experiment.

关键词： baryon spectroscopy photoproduction multi-meson final states polarisation observables

ADVANCED NICkEL-BASED AND NICkEL-IRON-BASED SuPERALLOYS FOR CIVIL ENGINEERING APPLICATIONS

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Acta Metallurgica Sinica(English Letters) 2005年第4期18卷 453-462页

作者： u. Brill Thyssenkrupp VDM GmbH 58791 Werdohl Germany

The use of high-temperature materials is especially important in power station construction, heating systems engineering, furnace in.ustry, chemical and petrochemical in.ustry, waste incineration plants, coal gasification plants and for flying gas turbines in civil and military aircrafts and helicopters. Particularly in recent years, the development of new processes and the drive to improve the economics of existing processes have increased the requirements significantly so that it is necessary to change from well-proven materials to new alloys. Hitherto, heat resistant ferritic steels sufficed in conventional power station constructions for temperatures up to 550℃ newly developed ferritic/martensitic steels provide sufficient strength up to about 600 - 620℃. In new processes, e.g. fluidized-bed combustion of coal, process temperatures up to 900℃ occur. However, this is not the upper limit, since in combustion engines, e.g. gas turbines. Material temperatures up to 1100℃ are reached locally. Similar development trends can also be identified in the petrochemical in.ustry and in the heat treatment and furnace engineering. The advance to ever higher material temperatures now not only has the consequence of having to use materials with enhanced high-strength properties, considerable attention now also has to be given to their chemical stability in corrosive media. Therefore not only examples of the use of high-temperature alloys for practical applications will be given but also be contributed to some general rules for material selection with regard to their high-temperature strength and corrosion resistance.

关键词： nickel-based alloy high-temperature strength high-temperature corrosion resistance civil engineering application

Review of studies on corrosion of magnesium alloys

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中国有色金属学会会刊：英文版 2006年第B02期16卷 763-771页

作者：曾荣昌张津黄伟九 W.DIETZEL k.u.kAINER C.BLAWERT 柯伟 School of Material Science and Engineering Chongqing Institute of Technology Chongqing 400050China School of Material Science and Engineering Chongqing Institute of Technology Chongqing 400050 China GkSS-Forschungszentrum Geesthacht GmbH Geesthacht 21502 Germany Environment Corrosion CenterInstitute of Metals Research Shenyang 110016China

This review provided some recent progress of the research on corrosion mechanisms of magnesium and its alloys and a basis for follow-on research. Galvanic corrosion, pitting corrosion, intergranular corrosion (IGC), filiform corrosion, crevice corrosion, stress corrosion cracking (SCC), and corrosion fatigue (CF) were discussed. The influence of metallurgical factors such as alloying elements, microstructure and secondary phases, processing factors such as heat treatment and weld, and environmental factors including temperature, relative humidity, solution pH values and concentration on corrosion were discussed. In particular, a mechanism of pitting corrosion caused by AlMn particles was proposed. The corrosion properties of AZ91D weld material were investigated.

关键词：镁合金腐蚀疲劳相对湿度研究综述

Spark plasma sintering of a high-energy ball milled Mg-10 wt% Al alloy

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Journal of Magnesium and Alloys 2020年第2期8卷 319-328页

作者： M.u.F.khan A.Patil J.Christudasjustus T.Borkar R.k.Gupta Department of Chemical Biomolecularand Corrosion EngineeringThe University of AkronAkronOH 44325United States Department of Mechanical Engineering Washkevicz College of EngineeringCleveland State UniversityClevelandOH 44115United States

The influence of spark plasma sintering(SPS)temperature on microstructure,hardness and corrosion behavior of a high-energy ball milled Mg-10wt%Al alloy was investigated in this *** holding time and sintering pressure for SPS were kept constant while varying the sintering temperature from 200 to 350℃.The grain size and microstructure were studied using X-ray diffraction analysis,scanning electron microscopy,energy dispersive X-ray spectroscopy,and Archimedes'based density *** behavior was investigated using potentiodynamic polarization *** nanocrystalline regime(grain sizeup to 350℃.The density of the alloy increased with increasing the SPS ***'hardness and corrosion performance improved up to 300℃ followed by a decrease after SPS at 350℃.Possible reasons for densification,strengthening,and corrosion behavior have been discussed in the light of reduced porosity and microstructural changes.

关键词： Nanocrystalline alloy Magnesium High energy ball milling Spark plasma sintering Corrosion

Investigation of soliton solutions with different wave structures to the(2+1)-dimensional Heisenberg ferromagnetic spin chain equation

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Communications in Theoretical Physics 2020年第3期72卷 7-13页

作者： M S Osman k u Tariq Ahmet Bekir A Elmoasry Nasser S Elazab M Younis Mahmoud Abdel-Aty Department of Mathematics Faculty of ScienceCairo UniversityGizaEgypt Department of Mathematics Faculty of Applied ScienceUmm Alqura UniversityMakkah 21955Saudi Arabia School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan 430074China Department of Mathematics Mirpur University of Science and TechnologyMirpur(AJK)10250Pakistan Neighbourhood of Akcaglan Imarli StreetNumber:28/426030EskisehirTurkey Mathematics department College of ScienceMajmaah UniversitySaudi Arabia Punjab university College of Information Technology University of the PunjabLahore 54590Pakistan Department of Mathematics Faculty of ScienceSohag UniversitySohagEgypt Applied Science university Bahrain

The principal objective of this article is to construct new and further exact soliton solutions of the(2+1)-dimensional Heisenberg ferromagnetic spin chain equation which investigates the nonlinear dynamics of magnets and explains their ordering in ferromagnetic *** solutions are exerted via the new extended FAN sub-equation *** successfully obtain dark,bright,combined bright-dark,combined dark-sin.ular,periodic,periodic sin.ular,and elliptic wave solutions to this equation which are interesting classes of nonlinear excitation presenting spin dynamics in classical and semi-classical contin.um Heisenberg systems.3D figures are illustrated under an appropriate selection of *** applied technique is suitable to be used in gaining the exact solutions of most nonlinear partial/fractional differential equations which appear in complex phenomena.

关键词： soliton solutions Heisenberg ferromagnetic equation FAN sub-equation method

HYDRODYNAMIC FORCES FOR OVERTOPPING SPILLWAYS

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Journal of Hydrodynamics 1993年第2期5卷 19-29页

作者： Ashok k.Chugh u.S.Department of the Interior,Bureau of Reclamation Eugineering and Research,Deuver,Colorado 80225 u.S. Dep of the Interior Denver United States

Expressions are derived for calculating hydrodynamic forces from the unit dis- charge,channel slope,and flow and velocity profiles on an overflow spillway.A sample prob- lem is included to illustrate the use of the id... 详细信息

关键词： hydrodynamic forces spillways embankment dam

APPLICATION OF Ct-PARAMETER FOR CREEP-FATIGuE CRACk GROWTH WITH SLOW LOAD RISING CONDITION

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Acta Metallurgica Sinica(English Letters) 1999年第1期12卷 22-30页

作者： Lee, J.H. Yoon, k.B. kim, Y.J. Back, u.B. korea Inst of Nuclear Safety Taejon South Korea

Most of the assessment equations for Ct which is a wellknown fracture parameter characterizing high temperature crack growth rates, have limited applicability to constant load conditions after sudden loading. However, crack growth due to creep can also occur under load varying conditions when load rising time is so long that accumulated creep deformation near the crack tip is not *** this paper, the estimation equation of the Ctparameter which can be applied to the case of slow load rising, i.e., (Ct)r, is explained. And the correlation between (Ct)r at the end of the load increasing period and Ct at the beginning of the succeeding load hold period is discussed. Finite element analyses of several cases with various loading conditions were performed and results were presented to show the effectiveness of the proposed Ct estimation scheme. The general applicability of the equation is also discussed.

关键词： creep fatigue crack time dependent fracture mechanics Ctparameter,C*integral

Bioaccumulation of Pb^(2+) and Its Effects on Growth,Morphology and Pigment Contents of Spirulina (Arthrospira) platensis

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Journal of Ocean university of China 2008年第4期7卷 397-403页

作者： k. k. I. u. Arunakumara ZHANG Xuecheng SONG Xiaojin College of Marine Life Sciences Ocean University of China Qingdao 266003 P R. China Department of Crop Science Faculty of Agriculture University of Ruhuna Mapalana Kamburupitiya Sri Lanka

A laboratory experiment was conducted to assess the bioaccumulation of Pb^2＋ and its effects on growth, morphology and pigment contents of Spirulina （Arthrosl）ira）platensis. The specimen cultured in Zarrouk liquid medium was treated with various initial metal concentrations （0, 5, 10, 30, 50 and 10μgmL^-1）. The growth ofS. platensis was adversely affected by Pb〉 at high concentrations （30, 50 and 100μgmL^-1）. However, at low concentrations （5μgmL^-1）, Pb^2＋ could stimulate its growth slightly. The pigment contents （chlorophyllα and β carotene） were decreased in a dose-dependent manner. The highest reductions （67% and 53% respectively in chlorophyll α andβ carotene） were observed in 100 μg mL^-1 treatment group. The LC50 （96 h） of Pb^2- was measured as 75.34 μg mL^-1. Apart from a few cases of filament breakages at elevated concentrations （50 and 100 μgmL^-1）, morphological abnormalities are not specific. Metal bioaccumulation increased with Pb^2- concentrations, but decreased with exposure time. The maximum accumulated amount was 188 mgg^-1 dry weight. The bioconcentration factor （BCF） reached to a peak at day 2, followed by a gradual reduction tbr all the exposure concentrations. S. platensis is able to tolerate considerably high Pb^2＋ concentrations. Consequently it can be used as a potential species to remove heavy metal from contaminated waters.

关键词： bioaccumulation growth pb^2+ Spirulina (Arthrospira)platensis

Compositional complexity dependence of dislocation density and mechanical properties in high entropy alloy systems

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Progress in Natural Science:Materials International 2020年第4期30卷 545-551页

作者： P.Thirathipviwat G.Song J.Bednarcik u.kühn T.Gemming k.Nielsch J.Han Leibniz Institute of Solid State and Materials Research (IFW Dresden) Frontier Research Center for Applied Atomic Sciences Ibaraki University Division of Advanced Materials Engineering and Institute for rare metals Kongju National University Institute of Physic Pavol Jozef Safarik University in Ko?ice Deutsches Elektronen-Synchrotron (DESY) Institute of Materials Science Technische Universit?t Dresden Institute of Applied Physics Technische Universit?t Dresden korea Institute for Rare Metals Korea Institute of Industrial Technology (KITECH)

This study focuses on a quantitative analysis of dislocation accumulation after cold plastic deformation and mechanical properties of Fe Ni Co Cr Mn and Ti Nb Hf Ta Zr high entropy alloys(HEAs) which are single phase fcc and bcc solid solutions, respectively. In order to study the role of compositional complexity from unary to quinary compositions on dislocation accumulation and mechanical properties after plastic deformation, the single solid solution phase forming sub-alloys of the two HEAs were investigated. All studied samples revealed a large plastic deformability under cold-rotary swaging process by 85–90% area reduction without intermediate annealing. The dislocation density of all studied samples, determined by Williamson-Hall method on synchrotron X-ray diffraction patterns, were between 1014-1015m-2dependent on the alloy composition. The level of dislocation density after plastic deformation is not only affected by the number of constituent element but the lattice distortion and intrinsic properties in terms of stacking fault energy, modulus misfit, and melting point also impact the dislocation storage. The level of dislocation density determines the level of mechanical properties because of a resistance to dislocation motions. The hardness and yield compressive strength of the studied samples are proportional to the level of dislocation density.

关键词： High entropy alloys Dislocation density Synchrotron XRD Mechanical properties