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Microstructure and Mechanical Property of the Large Cross-Sectioned Mg-Gd-y-Zn-Zr Alloy Produced by Small extrusion Ratio

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Acta Metallurgica Sinica(english Letters) 2024年第6期37卷 999-1006页

作者： Sen Wang Hucheng pan Caixia Jiang Zhihao Zeng Zhen pan Weineng Tang Chubin yang yuping Ren Gaowu Qin Key Laboratory for Anisotropy and Texture of Materials(Ministry of education) College of Materials Science and EngineeringNortheastern UniversityShenyang110819China Mg and Mg Alloy Institute Technology CenterBaosteel Metal Co.LtdChina Baowu Steel GroupShanghai200940China Jiangxi Provincial engineering Research Center for Magnesium Alloy Gannan Normal UniversityGanzhou341000China

In this work,the microstructure and mechanical properties of large cross-sectioned Mg-9Gd-3y-1.2Zn-0.5Zr(VWZ931)samples produced by the small extrusion ratio has been *** as-extruded VWZ931 sample with diameter of~30 mm can exhibit the high yield strength(yS)of 339 MPa,ultimate tensile strength(UTS)of 387 MPa and elongation of 8.2%,*** peak-aged,the yS and UTS of the Mg samples were significantly increased to 435 MPa and 467 *** small extrusion ratio leads to the low fraction of dynamic recrystallized(DRx)grains in VWZ931 sample,and the texture hardening effect can be fully utilized to achieve high *** combined effect of precipitation strengthening due to the long-period stacking ordered phases and theβ′phase,grain boundary strengthening due to the fine DRx grains,heterogeneous deformation-induced strengthening caused by bimodal microstructure,can together contribute to the high strength of present Mg *** findings can shed light on designing other large-sized Mg wrought alloys with high mechanical performance.

关键词： Mg-Re alloy Mechanical property Bimodal grains Texture hardening

Uphill or downhill?Cropland use change and its drivers from the perspective of slope spectrum

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Journal of Mountain Science 2024年第2期21卷 484-499页

作者： pan Sipei LIANG Jiale CHeN Wanxu PeNG yelin College of Land Management Nanjing Agricultural UniversityNanjing 210095China National&Local Joint engineering Research Center for Rural Land Resources Use and Consolidation Nanjing 210095China Jiangsu Provincial Key Laboratory of Geographic Information Technology School of Geography and Ocean ScienceNanjing UniversityNanjing 210023China Key Laboratory of Natural Resources Monitoring and Supervision in Southern Hilly Region Ministry of Natural ResourcesChangsha 410118China yunnan Key Laboratory of Plateau Geographic Processes and environmental Changes Faculty of GeographyYunnan Normal UniversityKunming 650500China Hubei Key Laboratory of Regional ecology and environmental Change School of Geography and Information EngineeringChina University of GeosciencesWuhan 430074China

The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food *** spectrum analysis of topographic and geomorphic features is considered as a digital terrain analysis method which reflects the macro-topographic features by using micro-topographic ***,pieces of studies have extended the concept of slope spectrum in the field of geoscience to construction land to explore its expansion law,while research on the slope trend of cropland from that perspective remains *** address the gap,in virtue of spatial analysis and geographically weighted regression(GWR)model,the cropland use change in the yangtze River Basin(yRB)from 2000 to 2020 was analyzed and the driving factors were explored from the perspective of slope *** showed that the slope spectrum curves of cropland area-frequency in the yRB showed a first upward then a downward *** change curve of the slope spectrum of cropland in each province(municipality)exhibited various distribution *** analysis of morphological parameters of cropland slope spectrum revealed that the further down the yRB,the stronger the flattening characteristics,the more obvious the *** province experienced the greatest downhill cropland climbing(CLC)was Shannxi,while province experienced the highest uphill CLC was *** most common cropland use change type in the yRB was horizontal expansion *** factors affecting average cropland climbing index(ACCI)were quite stable in different periods,while population density(POP)changed from negative to positive during the study *** research is of practical significance for the rational utilization of cropland at the watershed scale.

关键词： Cropland climbing Land use change Slope spectrum Driving factors Geographically weighted regression yangtze River Basin

editorial for Multiscale&Multifield Coupling in Geomechanics

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 1919-1921页

作者： Min Wang Pengzhi pan Andrew H.C.Chan y.T.Feng T-3 Fluid Dynamics and Solid Mechanics Theoretical DivisionLos Alamos National LaboratoryNew MexicoUSA Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhanChina School of engineering University of TasmaniaTasmaniaAustralia College of engineering Swansea UniversityWalesUK

We are delighted to serve as guest editors for this special issue in the Journal of Rock Mechanics and Geotechnical *** purpose of this special issue is dedicated to gathering the latest research work on Multiscale&Multifield Coupling in Geomechanics,where we delve into the intricate interplay of various fields and scales that govern the behavior of *** total,30 manuscripts from USA,China,UK,Germany,Canada,India and United Arab emirates are selected to be included in this issue.

关键词： materials. gathering mechanics

Numerical investigation of dynamic characteristics of dual throat nozzle and bypass dual throat nozzle in thrust vectoring starting process

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Chinese Journal of Aeronautics 2024年第10期37卷 184-206页

作者： yuqi ZHANG Jinglei xU Minglei CAO Ruifeng pan Shuai HUANG Key Laboratory of Inlet and exhaust System Technology of Ministry of education Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of energy and Power engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China State Key Laboratory of Mechanics and Control of Aeronautics and Astronautics Structures Nanjing 210016China

The Bypass Dual Throat Nozzle(BDTN)is a novel fluidic Thrust Vectoring(TV)nozzle,it switches to TV state by opening the valve in the *** greatly manipulate the BDTN,the dynamic characteristics in the TV starting process should be *** paper conducts numerical simulations to grasp the variation processes of performances and the flow field evolution of BDTN and Dual Throat Nozzle(DTN).The dynamic responses of TV starting in typical DTN models are investigated at ***,the TV starting processes of BDTN in different Nozzle Pressure Ratio(NPR)conditions are simulated,and the valve opening durations(T)are also *** the expected TV direction is achieved in the DTN,the jet is deflected to the opposite direction at the beginning of the dynamic process,which is called the reverse TV ***,this phenomenon disappears in the *** larger injection width of DTN intensifies unsteady oscillations,and the reverse TV phenomenon is *** the BDTN,T determines the delay degree of performance variations compared to the static results,which is called hysteresis *** NPR=10,the hysteresis affects the final stable performance of *** study analyses the dynamic characteristics in DTN and BDTN,laying a foundation for further design of nozzles and control strategies.

关键词： Dual Throat Nozzle(DTN) Bypass Dual Throat Nozzle(BDTN) Dynamic characteristic Thrust vectoring starting process Cavity vortex Hysteresis effect

effect of Wave Nonlinearity on the Instantaneous Seabed Liquefaction

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China Ocean engineering 2024年第1期38卷 93-103页

作者： WANG Zhao-jun SUI Ti-ti ZHANG Chi pan Jun-ning Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of TransportNanjing Hydraulic Research InstituteNanjing 210024China Key Laboratory of Coastal Disaster and Protection(Hohai University) Ministry of EducationNanjing 210098China The National Key Laboratory of Water Disaster Prevention Nanjing 210098China

The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal *** this study,an analytical formula considering the nonlinear wave skewness and asymmetry is adopted to provide wave pressure on the seabed *** liquefaction depth attenuation coefficient and width growth coefficient are defined to quantitatively characterize the nonlinear effect of wave on seabed *** on the 2D full dynamic model of wave-induced seabed response,a detailed parametric study is carried out in order to evaluate the influence of the nonlinear variation of wave loadings on seabed ***,new empirical prediction formulas are proposed to fast predict the maximum liquefaction under nonlinear *** indicate that(1)Due to the influence of wave nonlinearity,the vertical transmission of negative pore water pressure in the seabed is hindered,and therefore,the amplitude decreases significantly.(2)In general,with the increase of wave nonlinearity,the liquefaction depth of seabed decreases *** under asymmetric and skewed wave loading,the attenuation of maximum seabed liquefaction depth is the most significant among all the nonlinear wave ***,highly skewed wave can cause the liquefaction depth of seabed greater than that under linear wave.(3)The asymmetry of wave pressure leads to the increase of liquefaction width,whereas the influence of skewedness is not significant.(4)Compared with the nonlinear waveform,seabed liquefaction is more sensitive to the variation of nonlinear degree of wave loading.

关键词： nonlinear wave seabed response seabed liquefaction numerical simulation liquefaction prediction

extraordinary hot extreme in summer 2022 over the yangtze River basin modulated by the La Nina condition under global warming

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Advances in Climate Change Research 2024年第1期15卷 21-30页

作者： Zhen LIAO yu-Feng yUAN yang CHeN pan-Mao ZHAI State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China

A widespread and prolonged hot extreme hit the yangtze River basin in summer 2022,with 300 sites established new temperature records and nearly 96%stations endured more than 40 hot *** the perspective of the combination effect of the global warming and La Nina condition,potential mechanisms of the hot extreme were *** a record-breaking hot extreme was caused by an extremely strong and westward-shifted western Pacific subtropical high(WPSH).The global warming effect contributed primarily to the abnormal hot days in the yangtze River basin,coupled with the modulation of the La Nina *** sea surface temperature anomaly pattern under La Nina condition favored more convection activities over the western Pacific,encouraging an enhanced and westward-extended *** addition,an observation-based attribution analysis indicates that anthropogenic warming may increase the probability of such extensively persistent hot extremeby1.8 times.

关键词： Hot extreme The yangtze River basin Global warming Tropical Pacific forcing

Seedling dynamics differ between canopy species and understory species in a tropical seasonal rainforest,SW China

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Plant Diversity 2024年第5期46卷 671-677页

作者： Libing pan xiaoyang Song Wenfu Zhang Jie yang Min Cao CAS Key Laboratory of Tropical Forest ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglunMengla 666303YunnanChina College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China

We used 11 years of census data from 450 seedling quadrats established in a 20-ha forest dynamics plot to study seedling dynamics in tree species of a tropical seasonal rainforest in xishuangbanna,southwestern *** found that overall seedling recruitment rate and relative growth rate were higher in the rainy season than in the dry *** the recruitment rate of seedlings from canopy tree species(two species)and the relative growth rate of seedlings from understory species(nine species)were higher in the rainy season than in the dry ***,in the rainy season,the recruitment rate of seedlings was higher for canopy tree species than for understory tree *** addition,relative growth rate of seedlings was higher in the canopy species than in understory seedlings in the dry *** also observed that,in both rainy and dry seasons,mortality rate of seedlings was higher for canopy species than for understory ***,canopy tree species appear to have evolved a flexible strategy to adapt to the seasonal changes of a monsoon *** contrast,understory tree species seem to have adopted a conservative ***,these species mainly release seedlings in the rainy season and maintain relatively stable populations with a lower mortality rate and recruitment rate in both dry and rainy *** study suggests that canopy and understory seedling populations growing in forest understory may respond to future climate change scenarios with distinct regeneration strategies.

关键词： Tropical forest Tree seedling Seasonality Recruitment Mortality Relative growth rate

Fabrication of AZ31/Mg3y Composites with excellent Strength and Plasticity via Accumulated Rolling Bonding and Diffusion Annealing

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Acta Metallurgica Sinica(english Letters) 2024年第2期37卷 339-352页

作者： yang Feng Wenhuan Chen Zheng xu Weijun He Bin Jiang Fusheng pan College of Materials Science and engineering Chongqing UniversityChongqing400044China International Joint Laboratory for Light Alloys(Ministry of education) Chongqing UniversityChongqing400044China

AZ31/Mg3y composites with a layer thickness of 100-200μm were fabricated by accumulated rolling bonding(ARB),which was followed by diffusion annealing at 300℃ for 0-32 *** interface layer,containing numerous Al-y precipitates,is formed in the Mg3y layer that is adjacent to the interface as a result of Al diffusing from the AZ31 layers into the Mg3y *** thickness of the interface layer gets increased and more precipitates are formed in the interface layer with the extension of the annealing *** microhardness of the AZ31 and Mg3y layer decreases firstly and then reaches a stable value,while the microhardness of the interface layer increases gradually with the extension of the annealing *** AZ31/Mg3y composites exhibit equivalent strength but increased ductility after diffusion annealing,in comparison to the as-rolled AZ31/Mg3y *** addition,the AZ31/Mg3y composites after annealing always present higher strength and ductility than AZ31/AZ31 composite,which was fabricated by the same process as that for the AZ31/Mg3y ***-deformation induced strengthening also plays an important role in the excellent strength and ductility of the annealed AZ31/Mg3y *** study can provide a direction for improving the plasticity and strength of magnesium alloys synergistically.

关键词： AZ31/Mg3y composite Accumulated rolling bonding Diffusion annealing Precipitates Strengthening

Influence of Micro/Nano-Ti Particles on the Corrosion Behavior of AZ31-Ti Composites

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Acta Metallurgica Sinica(english Letters) 2024年第3期37卷 484-498页

作者： Jinchao Jiao Jin Zhang yong Lian Shengli Han Kaihong Zheng Fusheng pan Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 10083China Beijing Key Laboratory for Corrosion erosion and Surface Technology Beijing 100083China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China National engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 404100China

Adding Ti particles to magnesium alloy simultaneously enhances its strength and ***,how these particles influence on Mg alloy’s corrosion performance is seldom *** corrosion behavior of AZ31-Ti composites containing titanium nanoparticles(1.5 and 5 wt%)and micron particles(10 wt%)prepared by powder metallurgical in 3.5 wt%NaCl solution was *** results indicate that Ti particles serve as the primary location for the cathodic hydrogen reduction reaction,resulting in intense galvanic corrosion between the Ti and Mg *** nanoparticles distributed at the interface of the original AZ31 powder were in a discontinuous mesh structure,thus failing to act as a barrier against *** corrosion products with the existence of numerous cracks gradually peel off during the corrosion process and cannot protect the *** average corrosion rate P_(w) of AZ31,AZ31-1.5%Ti,AZ31-5%Ti,and AZ31-10%Ti after 7 days of immersion is 27.55,105.65,283.67,and 99.35 mm/y,***,AZ31-Ti composites can be considered as potential candidates for degradable fracturing ***,it is recommended to improve their corrosion resistance through surface treatment.

关键词： AZ31-Ti composite Nano-Ti Micro-Ti Corrosion behavior Scanning Kelvin probe force microscopy(SKPFM)