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Measurements of γ/γ' Lattice Misfit and γ' Volume Fraction for a Ru-containing Nickel-based Single Crystal Superalloy

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Journal of Materials Science & Technology 2011年第10期27卷 899-905页

作者： X.P. Tan J.L. Liu X P Song T. Jin X.F. sun Z.q. Hu Superalloy Division Institute of Metal Research Chinese Academy of Sciences- Shenyang 110016 China Analysis and Testing Division Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

A conventional X-ray difFractometer has been used to determine the -y/y＇ lattice misfit and γ＇ volume fraction for a Ru-containing nickel-based single crystal superalloy at room temperature. The rocking curve was used to characterize the distribution of subgrains. The diffraction peaks obtained by w-20 scan were used to determine the γ/γ＇ lattice misfit and γ＇ volume fraction. A three peaks fitting model was proposed. The peak fitting results are in good agreement with the model. The X-ray diffraction results indicate that the nickel-based single crystal superalloy was not a perfect monocrystalline material, which is comprised of many subgrains; and each subgrain also consists of large numbers of mosaic structures. In addition, two anomalous reflection phenomena were found during the experiment and discussed with respect to their occurrence and impact on the measurement. The experimental results show that the γ/γ＇ lattice misfit and ~/r volume fraction will be various at the different regions of its dendritic microstructure. The average γ/γ＇ lattice misfit and γ＇ volume fraction of the experimental alloy are approximately-0.2% and 70%, respectively. Furthermore, the γ＇ volume fraction calculated by atom microprobe （AP） data is also basically consistent with the experimental results.

关键词： Nickel-based superalloy Microstructure X-ray diffraction Lattice misfit y' volume fraction

GRACE terrestrial water storage data assimilation based on the ensemble four-dimensional variational method PODEn4DVar:Method and validation

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Science China Earth Sciences 2015年第12期58卷 371-384页

作者： sun qin XIE ZhengHui TIAN XiangJun State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences Numerical Weather Prediction Center China Meteorological Administration

Seasonal and interannual changes in the Earth's gravity field are mainly due to mass exchange among the atmosphere,ocean,and continental water *** terrestrial water storage changes,detected as gravity changes by the Gravity Recovery and Climate Experiment(GRACE) satellites,are mainly caused by precipitation,evapotranspiration,river transportation and downward infiltration *** this study,a land data assimilation system LDAS-G was developed to assimilate the GRACE terrestrial water storage(TWS) data into the Community Land Model(CLM3.5) using the POD-based ensemble four-dimensional variational assimilation method PODEn4 DVar,disaggregating the GRACE large-scale terrestrial water storage changes vertically and in time,and placing constraints on the simulation of vertical hydrological variables to improve land surface hydrological *** ideal experiments conducted at a single point and assimilation experiments carried out over China by the LDAS-G data assimilation system showed that the system developed in this study improved the simulation of land surface hydrological variables,indicating the potential of GRACE data assimilation in large-scale land surface hydrological research and applications.

关键词： data assimilation land surface model terrestrial water storage ensemble four-dimensional variational data assimilation method

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Risk management for sulfur dioxide abatement under multiple uncertainties

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Frontiers of Earth Science 2016年第1期10卷 87-107页

作者： C. DAI W. sun q. TAN Y. LIU W.T. LU H.C. GUO College of Environmental Science and Engineering Peking University Beijing 100871 China Institute for Energy Environment and Sustainable Communities University of Reginal Regina Saskatchewan S4S 7H9 Canada College of Water Resources & Civil Engineering China Agricultural University Beijing 100083 China

In this study, interval-parameter programming, two-stage stochastic progranaming （TSP）, and conditional value-at-risk （CVaR） were incorporated into a general optimization framework, leading to an interval-parameter CVaR-based two-stage programming （ICTP） method. The ICTP method had several advantages：（i） its objective function simultaneously took expected cost and risk cost into consideration, and also used discrete random variables and discrete intervals to reflect uncertain properties; （ii） it quantitatively evaluated the right tail of distributions of random variables which could better calculate the risk of violated environmental standards; （iii） it was useful for helping decision makers to analyze the trade-offs between cost and risk; and （iv） it was effective to penalize the second-stage costs, as well as to capture the notion of risk in stochastic programming. The developed model was applied to sulfur dioxide abatement in an air quality management system. The results indicated that the ICTP method could be used for generating a series of air quality management schemes under different risk-aversion levels, for identifying desired air quality management strategies for decision makers, and for considering a proper balance between system economy and environmental quality.

关键词： risk management conditional value-at-risk,interval optimization two-stage programming uncertainty,air quality management

Adaptive region reaching control of fully actuated ocean surface vessels

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Journal of Control and Decision 2021年第3期8卷 251-259页

作者： X.M.sun S.S.Ge q.Xu Y.Zhou X.W.Zheng School of Engineering Science and Technology Shanghai Ocean UniversityShanghai 201306People’s Republic of China Robotics Institute and School of Computer Science and EngineeringUniversity of Electronic Science and Technology of ChinaChengduPeople’s Republic of China School of Electrical and Computer Engineering National University of SingaporeSingaporeSingapore School of Electronic and Information Engineering Beihang UniversityBeijingPeople’s Republic of China

In this paper,region reaching controller is designed for fully actuated ocean surface vessels to reach a desired target region instead of a *** are not the requirements for both the pre-specified trajectory outside the desired region and the desired pinpoint position inside the desired *** controller design is based on the potential energy function,backstepping recursive design methodology,and the Lyapnov stability analysis *** the target region is specified arbitrarily small,the target region reduces to a point,and hence the region reaching control can be a generalisation of the setpoint *** results are presented to illustrate the performance of the proposed controller.

关键词： Reaching control potential energy function adaptive control backstepping technique Lyapunov stability

PROPERTIES OF MgB_2 FILMS FABRICATED ON COPPER CATHODES BY ELECTROCHEMICAL TECHNIqUE

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Acta Metallurgica Sinica(English Letters) 2008年第5期21卷 351-354页

作者： H.Z. Yang X.G. sun W.q. Huang M.L. Li X.M. Yu B.S. Zhang Y. qi q. Zhao Institute of Materials Physics and Chemistry School of Sciences Northeastern University Shenyang 110004 China Key Laboratory for Anisotropy and Texture of Materials Ministry of Education Northeastern University Shenyang 110004 China Department of Applied Physics School of Sciences Shenyang University of Technology Shenyang 110178 China

An electrochemical technique has been introduced and applied to fabricate superconducting MgB2 films in molten salts. MgCl2, Mg（BO2）2, NaCl, and KCl were used as electrolyte, graphite was used as the anode, and copper was used as the cathode, respectively. X-ray diffraction （XRD） analysis was chosen to investigate the phase composition and crystallinity of the films at different electrolysis temperatures. Stan- dard four-probe technique and SqUID were applied to investigate the temperature dependence of resistance （R-T） properties and magnetic properties of the films, respectively. The results indicate that MgB2 films have been fabricated on the copper cathodes, and superconducting transition takes place close to 50 K.

关键词： MgB2 film Electrochemistry Cu cathode

An insight into a novel Mg2InSm prismatic plate in Mg-In-Sm alloy

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Journal of Materials Science & Technology 2022年第30期125卷 222-230页

作者： J.Wang X.L.Lu Y.Tian q.Y.Huang H.B.Xie B.Z.sun L.R.Liu School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Key Laboratory for Anisotropy and Texture of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

Prismatic precipitate platelet is always purposefully designed in the microstructure of magnesium alloys due to its greater contribution to yield *** this study,with an introduction of In into Mg-Sm system,a category of novel{1010}_(α) prismatic platelets has replaced thoroughly the traditionalβ’precipitate formed in magnesium rare earth(Mg-RE)***,the microstructural characteristics of platelet are investigated particularly by atomic scale scanning transmission electron *** is confirmed that the platelet has a Mg_(2) InSm composition and can maintain a coherent relationship with α-Mg ***,on account of the similarities between In and Mg atoms,the Mg_(2) InSm prismatic platelet could be structurally categorized as a generalizedβ"precipitate with a(Mg_(2) In)Sm-type DO_(19) structure when both In and Mg are regarded as an equivalent ***,the addition of In into Mg-Sm alloy induces the formation ofβ"***,the formedβ"prismatic platelets generally have a large average aspect *** findings are of great significance to construct the effective precipitation strengthening phases and optimize the microstructure of Mg-based alloys.

关键词： Microstructure Scanning transmission electron microscopy Magnesium alloys Prismatic platelet Generalizedβ"precipitate

Selective Hydrodeoxygenation of Lignin-Derived Vanillin via Hetero-Structured High-Entropy Alloy/Oxide Catalysts

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Energy & Environmental Materials 2024年第3期7卷 202-210页

作者： Yan sun Kaili Liang Ren Tu Xudong Fan Charles q.Jia Zhiwen Jia Yingnan Li Hui Yang Enchen Jiang Hanwen Liu Yonggang Yao Xiwei Xu Key Laboratory for Biobased Materials and Energy of Ministry of Education College of Materials and EnergySouth China Agricultural UniversityGuangzhou 510640China Department of Chemical Engineering and Applied Chemistry University of Toronto200 College StreetToronto ON M5S3E5Canada State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The chemoselective hydrodeoxygenation of natural lignocellulosic materials plays a crucial role in converting biomass into value-added *** their complex molecular structures often require multiple active sites synergy for effective activation and achieving high ***,it is reported that a high-entropy alloy(HEA)on high-entropy oxide(HEO)hetero-structured catalyst for highly active,chemoselective,and robust vanillin *** heterogenous HEA/HEO catalysts were prepared by thermal reduction of senary HEOs(NiZnCuFeAlZrO_(x)),where exsolvable metals(e.g.,Ni,Zn,Cu)in situ emerged and formed randomly dispersed HEA nanoparticles anchoring on the HEO *** catalyst exhibits excellent catalytic performance:100%conversion of vanillin and 95%selectivity toward high-value 2-methyl-4 methoxy phenol at low temperature of 120℃,which were attributed to the synergistic effect among HEO matrix(with abundant oxygen vacancies),anchored HEA nanoparticles(having excellent hydrogenolysis capability),and their intimate hetero-interfaces(showing strong electron transferring effect).Therefore,our work reported the successful construction of HEA/HEO heterogeneous catalysts and their superior multifunctionality in biomass conversion,which could shed light on catalyst design for many important reactions that are complex and require multifunctional active sites.

关键词： biomass conversion heterogeneous catalysts high-entropy oxide high-entropy alloys lignin pyrolysis

Numerical study on static and dynamic fracture evolution around rock cavities

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Journal of Rock Mechanics and Geotechnical Engineering 2013年第4期5卷 262-276页

作者： S.Y.Wang L.sun C.Yang S.q.Yang C.A.Tang ARC Centre of Excellence for Geotechnical Science and Engineering The University of Newcastle Department of Civil Engineering Catholic University of America School of Transportation Southeast University Centre for Geotechnical and Materials Modelling Department of CivilSurveying and Environmental EngineeringThe University of Newcastle State Key Laboratory for Geomechanics and Deep Underground Engineering School of Mechanics and Civil EngineeringChina University of Mining and Technology School of Civil and Hydraulic Engineering Dalian University of Technology

In this paper,a numerical code,RFPA2D（rock failure process analysis）,was used to simulate the initiation and propagation of fractures around a pre-existing single cavity and multiple cavities in brittle *** static and dynamic loads were applied to the rock specimens to investigate the mechanism of fracture evolution around the cavities for different lateral pressure *** addition,characteristics of acoustic emission（AE） associated with fracture evolution were ***,the evolution and interaction of fractures between multiple cavities were investigated with consideration of stress redistribution and transference in compressive and tensile stress *** numerically simulated results reproduced primary tensile,remote,and shear crack fractures,which are in agreement with the experimental ***,numerical results suggested that both compressive and tensile waves could influence the propagation of tensile cracks;in particular,the reflected tensile wave accelerated the propagation of tensile cracks.

关键词： Cracks Dynamic loading Numerical simulations Acoustic emission(AE) Heterogeneity

2013年北大西洋破纪录高海温与我国江淮-江南地区极端高温的关系

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科学通报 2014年第27期59卷 2714-2719页

作者：孙建奇中国科学院大气物理研究所竺可桢-南森国际研究中心北京100029

2013年7月,我国江淮-江南地区持续高温,多个地区气温打破历史纪录,影响重大.本文从气候学的角度开展了其归因研究,结果发现在2013年7月,北大西洋中纬度地区海温持续偏高,打破160年的历史纪录,海温的异常通过遥相关波列与东亚上空纬向西... 详细信息

2013年7月,我国江淮-江南地区持续高温,多个地区气温打破历史纪录,影响重大.本文从气候学的角度开展了其归因研究,结果发现在2013年7月,北大西洋中纬度地区海温持续偏高,打破160年的历史纪录,海温的异常通过遥相关波列与东亚上空纬向西风和西太平洋副热带高压产生联系,进而可能影响到我国江淮-江南地区夏季气温的变化,这可能是造成该地区2013年7月破纪录高温事件的重要原因.对于江淮-江南地区的极端高温,一般关注的是西太平洋副热带高压的影响.本研究指出,江淮-江南地区上空纬向西风的变化也是影响该地区夏季气温变化的重要气候因子,尤其是2013年7月,该地上空纬向西风破纪录的偏弱与夏季气温破纪录的偏高密切相关.这意味着,对于我国江淮-江南地区夏季气温和极端高温事件的研究,不但需要关注西太平洋副热带高压的作用,还需要关注高层纬向风的变化.

关键词：极端高温北大西洋西太平洋副热带高压纬向西风海温

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