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Evolution of the corrosion Product Film and Its Effect on the Erosion–corrosion Behavior of Two commercial 90cu–10Ni Tubes in Seawater

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Acta Metallurgica Sinica(English Letters) 2018年第11期31卷 1148-1170页

作者： Okpo O. Ekerenam Ai-Li ma Yu-Gui Zheng Si-Yu He Peter c. Okafor cAS Key Laboratory of Nuclear materials and Safety Assessment Institute of Metal Research Chinese Academyof Sciences Shenyang 110016 China University of chinese Academy of Sciences (UcAS) Beijing 100049 China Department of Pure and Applied chemistry University of Calabar PMB 1115 Calabar CRS Nigeria

The composition and structural evolution of the corrosion product film of two commercial 90cu-10Ni tubes, namely TubeA and Tube B, after being immersed in natural seawater for 1, 3, and 6 months were characterized by scanning electronmicroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and its effecton the erosion--corrosion behavior of the tubes was determined through a rotating cylinder electrode system using variouselectrochemical techniques. For the freshly polished samples used as contrast samples, the flow velocity mainly enhancedthe cathodic reaction at low flow velocities while both the anodic and the cathodic reactions were remarkably accelerated athigher flow velocities. The corrosion product films formed on the two commercial 90cu-10Ni tubes after being immersedin seawater for up to 6 months are of a complex three-layer or multilayer structure. The structural evolution of the films isout of sync for the two tubes. A continuous residual substrate layer depleted of Ni was observed in the inner layer of thefilms on Tube B after 30, 90, and 180 days＇ immersion, while it was observed in the film on Tube A only after 180 days＇immersion. The nature of the inner layer plays a crucial role in the erosion-corrosion resistance of the 90cu-10Ni tubes athigher flow velocity. The film with a compact and continuous inner layer of cu20 doped with Ni2＋ and Ni3＋ which bondsfirmly with the substrate could survive and even get repaired with the increased flow velocity. The film on Tube Bpossessing a hollow and discontinuous inner layer composed of the residual substrate was degraded rapidly with increasingrotation speed in spite of its quite good resistance at the stagnant or lower speed conditions.

关键词： copper-nickel alloy Seawater immersion Erosion-corrosion corrosion product film Flow velocity

Evolution of microstructure and phase composition of Ti-3Al-5Mo-4.5V alloy with varied β phase stability

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Journal of materials Science & Technology 2018年第12期34卷 2325-2330页

作者： Q.Xue Y.J.ma J.F.Lei R.Yang c.Wang School of Metallurgy Northeastern University Institute of Metal Research Chinese Academy of Sciences

The microstructure evolution and phase composition of an α+β titanium alloy, Ti-3Al-5Mo-4.5V(wt.%),have been investigated. Electron probe micro analysis(EPma) quantitative results manifest that the stability of β phase decreases with increasing quenching temperature, which is influenced by the significant variation of β-stabilizing elements concentration. Detailed microstructure analysis shows that the β→ωphase transformation does occur when quenching at 750℃ and 800 ℃. The ω-reflections change from incommensurate ω-spots(750 ℃) to ideal ω-spots(800 ℃) as the β stability of the alloy decreases. Further the decrease of β phase stability encourages the formation of athermal α " martensite, which has the following orientation relationships: [111]β//[110]α",[100]p//[100]α " and [-110]p//[00-1]α" with respect to the β matrix.

关键词： Dual-phase titanium alloy β phase stability ω phase α" martensite Microstructure

Formation of a new intermediate phase and its evolution toward θ’ during aging of pre-deformed Al-cu alloys

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Journal of materials Science & Technology 2019年第5期35卷 885-890页

作者： Peipei ma chunhui Liu Ziyao ma Lihua Zhan Minghui Huang Light Alloy Research Institute of central South University State Key Laboratory of High-Performance Complex Manufacturing Central South University Changsha 410083 China School of Mechanical and Electrical Engineering Central South University Changsha 410083 China

The frequent occurrence of hitherto unknown phase Pre-θ′-2 and unusual 1.5 cθ′thick θ′precipitate was observed by atomic-resolution scanning transmission electron microscopy in the well-studied Al-cu alloys. This phenomenon is associated with heterogeneous precipitate nucleation and growth on preexisting dislocations introduced by slight deformation prior to aging. In this study, the precise structure details of Pre-θ′-2 was determined by atomic scale imaging, image simulation based on image forming theories and first principle calculations. Pre-θ′-2 has a well-defined ordered structure sandwiched between two 2 aAl(~1.5 cθ′) spaced cu layers on {200}Alplanes. The strong structural similarities between Pre-θ′-2 and 1.5 cθ′ thick θ′ in terms of interfacial structure and thickness, coupled with energetic calculations and preliminary in-situ observations, lead us to propose a new precipitation path toward key strengthening phase θ′

关键词： Aluminum alloys Precipitation Deformation Age-harde ning

Mechanical properties and deformation mechanisms of Ti-3Al-5Mo-4.5V alloy with varied β phase stability

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Journal of materials Science & Technology 2018年第12期34卷 2507-2514页

作者： Q.Xue Y.J.ma J.F.Lei R.Yang c.Wang Institute of Metal Research Chinese Academy of Sciences School of Metallurgy Northeastern University

Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenching temperature variation from dual α+β field(700℃) to single β field(880℃). Tensile tests at ambient temperature show that apparent yield strength of the alloy experiences an abrupt decrease followed by a significant increase from 700℃ to 880℃. Work hardening behavior is characterized by transition from the initial two-regime feature to the three-stage outlook. concurrently, the maximum working hardening rate drops from 14000 MPa to 3000 MPa, which is concurrent with the shrinking volume fraction of primary a phase. Detailed discussion about the relationship between deformation mechanisms and β phase stability has been outlined.

关键词： Dual-phase titanium alloy β phase stability Work hardening behavior Deformation mechanisms

Pathogenicity of Serratia marcescens to hazelnut weevil(curculio dieckmanni)

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Journal of Forestry Research 2021年第1期32卷 409-417页

作者： Ping Zhang Qingquan Zhao Xiaoqian ma Ling ma college of Forestry Northeast Forestry University26 Hexing RoadHarbin 150040People’s Republic of China Forest Protection Research Institute Heilongjiang Academy of ForestryHaping RoadHarbin 150081People’s Republic of China

The hazelnut weevil(curculio dieckmanni Faust.)is a major pest of Asian hazel(corylus heterophylla Fisch.)in *** hazelnut weevil larvae were examined and the associated pathogenic bacterium was identifi ed as Serratia marcescens *** signifi cantly shortened the lifespan of hazelnut *** weight was reduced as a function of *** concentration and exposure *** structure of infected midgut cells was altered,with necrosis of the wall tissues and many cells becoming dislodged,creating *** *** strain inhibited digestive enzyme activity and protective enzymes in the midgut of adult hazelnut *** on *** strain increased with treatment *** directly destroyed the midgut cells and interfered with digestive and protective *** decreased the food intake and increased mortality of hazelnut *** appears to be an eff ective bacterium for the control of hazelnut weevil but requires further study,including biological formulation development and fi eld application.

关键词： Biocontrol curculio dieckmanni corylus heterophylla Pathogenic mechanism Serratia marcescens

Micro-scaled plastic yielding and shear-banding dynamics in metallic glasses

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Journal of materials Science & Technology 2023年第21期152卷 237-246页

作者： D.X.Han G.Wang Q.Wang R.Feng X.D.ma K.c.chan c.T.Liu Institute of materials Shanghai UniversityShanghai 200444China Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHong KongChina Neutron Scattering Division Oak Ridge National LaboratoryOak RidgeTN 37831United States Department of material Science and Engineering College of Science and EngineeringCity University of Hong KongHong KongChina center for Advanced Structural materials College of Science and EngineeringCity University of Hong KongHong KongChina

Shear-banding behavior in metallic glasses plays a key role in the operation of plastic deformation,which is associated with yield *** a micro-scale,the shear-banding behavior must be affected by many factors from the test machine and the ***,in this study,comprehensively considering a machine compliance,a geometry imperfection of micro-pillar,and a substrate sink-in the machine-sample-substrate system,we developed a plastic-strength model at a micrometer scale in this study,which is evidenced by the microscale compressive properties of 18 kinds of metallic *** the-oretical model provides a guidance for the elastic limits and shear-banding dynamics of metallic glasses at the micro-scale,which can be applicable to characterize the microscale deformation behavior of other amorphous materials.

关键词： Metallic glasses Shear-banding dynamics Micro-compression Plastic deformation

Mono-γ production of a dark vector at future e^(+)e^(−) colliders

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chinese Physics c 2022年第11期46卷 106-117页

作者： Kai ma School of Fundamental Physics and mathematical Science Hangzhou Institute for Advanced StudyUCASHangzhou 310024China University of chinese Academy of Sciences(UcAS) Beijing 100049China Department of Physics Shaanxi University of TechnologyHanzhong 723000China Tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China

The associated production of a dark particle and photon,represented as a mono-γevent,is a promising channel to probe particle content and dynamics in the dark *** this study,we investigate the properties of the mono-γ production of vector dark matter at future e^(+)e^(−) ***-like and Pauli operators as well as triple gauge boson interactions involving dark matter are considered in the framework of effective field *** show that,in comparison with the Pauli operator,the triple gauge boson couplings are significantly more interesting in high energy *** polarization effects are also analyzed,and we show that the experimental sensitivities cannot be significantly enhanced because of the smaller luminosity.

关键词： dark matter lepton collider mono-photon

Porous g-c3N4 with enhanced adsorption and visible-light photocatalytic performance for removing aqueous dyes and tetracycline hydrochloride

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chinese Journal of chemical Engineering 2018年第4期26卷 753-760页

作者： Junlei Zhang Zhen ma Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP^3) Department of Environmental Science and Engineering Fudan University Shanghai 200433 China Shanghai Institute of Pollution control and Ecological Security Shanghai 200092 PR China

Porous g-c3N4samples were obtained by simply calcining bulk g-c3N4in static air in a muffle *** photocatalytic performance of these samples was evaluated through the removal of aqueous organic dyes（methylene blue and methyl orange）and tetracycline hydrochloride under visible-light irradiation（λ〉420 nm）.compared to bulk g-c3N4,porous g-c3N4exhibited much better capability for removing these contaminants,especially under visible-light irradiation,due to the enlarged specific surface area and more efficient separation of photogenerated charge *** particular,porous g-c3N4obtained by calcining bulk g-c3N4in air at 525℃ showed the highest visible-light-driven catalytic activity among these *** radical anions（·O2^-）were found to be the primary active species responsible for photodegradation.

关键词： c3N4 catalyst Reaction Waste treatment Dyes Tetracycline hydrochloride

Improved Parameterization of Snow Albedo in WRF+Noah:Methodology Based on a Severe Snow Event on the Tibetan Plateau

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Advances in Atmospheric Sciences 2022年第7期39卷 1079-1102页

作者： Lian LIU massimo MENENTI Yaoming ma Weiqiang ma Land-Atmosphere Interaction and its climatic Effects Group State Key Laboratory of Tibetan Plateau Earth SystemResources and Environment(TPESRE)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China State Key Laboratory of Remote Sensing Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China Delft University of Technology Delft 2600AANetherlands college of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China college of Atmospheric Science Lanzhou UniversityLanzhou 730000China National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental changes Dingri 858200China Kathmandu center of Research and Education Chinese Academy of SciencesBeijing 100101China china-Pakistan Joint Research center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakistan

Snowfall and the subsequent evolution of the snowpack have a large effect on the surface energy balance and water cycle of the Tibetan Plateau(TP).The effects of snow cover can be represented by the WRF coupled with a land surface *** widely used Noah scheme is computationally efficient,but its poor representation of albedo needs considerable *** this study,an improved albedo scheme is developed using a satellite-retrieved albedo that takes snow depth and age into *** experiments were then conducted to simulate a severe snow event in march *** performance of the coupled WRF/Noah model,which implemented the improved albedo scheme,is compared against the model’s performance using the default Noah albedo scheme and against the coupled WRF/cLM that applied cLM albedo *** the improved albedo scheme is implemented,the albedo overestimation in the southeastern TP is reduced,reducing the RMSE of the air temperature by 0.7°*** improved albedo scheme also attains the highest correlation between the satellite-derived and the model-estimated albedo,which provides for a realistic representation of both the snow water equivalent(SWE)spatial distribution in the heavy snowbelt(SWE>6 mm)and the maximum SWE in the eastern *** underestimated albedo in the coupled WRF/cLM leads to underestimating the regional maximum SWE and a consequent failure to estimate SWE in the heavy snowbelt *** study demonstrates the feasibility of improving the Noah albedo scheme and provides a theoretical reference for researchers aiming to improve albedo schemes further.

关键词： WRF MODIS severe snowfall albedo scheme SWE Tibetan Plateau