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Effects of zero-valent iron added in the flooding or drainage process on cadmium immobilization in an acid paddy soil

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Journal of Environmental Sciences 2024年第4期138卷 19-31页

作者： Hanbing Meng Shiwen Hu zebin Hong Wenting Chi Guojun Chen Kuan Cheng QiWang Tongxu liu Fangbai Li Kexue liu Yang Yang Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640China National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China School of Resources and Planning Guangzhou Xinhua UniversityGuangzhou 510310China University of Chinese Academy of Sciences Beijing 100049China

Zero-valent iron(ZVI)is a promising material for the remediation of Cd-contaminated paddy soils.However,the effects of ZVI added during flooding or drainage processes on cadmium(Cd)retention remain unclear.Herein,Cd-contaminated paddy soil was incubated for 40days of flooding and then for 15 days of drainage,and the underlying mechanisms of Cd immobilization coupled with Fe/S/N redox processes were investigated.The addition of ZVI to the flooding process was more conducive to Cd immobilization.Less potential available Cd was detected by adding ZVI before flooding,which may be due to the increase in paddy soil pH and newly formed secondary Fe minerals.Moreover,the reductive dissolution of Fe minerals promoted the release of soil colloids,thereby increasing significantly the surface sites and causing Cd immobilization.Additionally,the addition of ZVI before flooding played a vital role in Cd retention after soil drainage.In contrast,the addition of ZVI in the drainage phase was not conducive to Cd retention,which might be due to the rapid decrease in soil pH that inhibited Cd adsorption and further immobilization on soil surfaces.The findings of this study demonstrated that Cd availability in paddy soil was largely reduced by adding ZVI during the flooding period and provide a novel insight into the mechanisms of ZVI remediation in Cd-contaminated paddy soils.

关键词： Paddy soil Zero-valent iron Cadmium Flooding and drainage Remediation

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Implementation of a particle-in-cell method for the energy solver in 3D spherical geodynamic modeling

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Earth and Planetary Physics 2024年第3期8卷 549-563页

作者： Hao Dong zebin Cao LiJun liu YanChong Li SanZhong Li LiMing Dai XinYu Li Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Laboratory of Submarine Geosciences and Prospecting TechniquesMinistry of Education and College of Marine GeosciencesOcean University of ChinaQingdao 266100China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Laboratory for Marine Geology Laoshan LaboratoryQingdao 266237China Department of Earth Science&Environmental Change University of Illinois at Urbana-ChampaignUrbanaIL 61801USA Laboratory of Seismology and Physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China

The thermal evolution of the Earth’s interior and its dynamic effects are the focus of Earth sciences.However,the commonly adopted grid-based temperature solver is usually prone to numerical oscillations,especially in the presence of sharp thermal gradients,such as when modeling subducting slabs and rising plumes.This phenomenon prohibits the correct representation of thermal evolution and may cause incorrect implications of geodynamic processes.After examining several approaches for removing these numerical oscillations,we show that the Lagrangian method provides an ideal way to solve this problem.In this study,we propose a particle-in-cell method as a strategy for improving the solution to the energy equation and demonstrate its effectiveness in both one-dimensional and three-dimensional thermal problems,as well as in a global spherical simulation with data assimilation.We have implemented this method in the open-source finite-element code CitcomS,which features a spherical coordinate system,distributed memory parallel computing,and data assimilation algorithms.

关键词： numerical oscillation overshooting and undershooting particle-in-cell method three-dimensional spherical geodynamic modeling energy solver finite element method

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Environmental and canopy conditions regulate the forest floor evapotranspiration of larch plantations

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Forest Ecosystems 2022年第5期9卷 606-616页

作者： zebin liu Yanhui Wang Pengtao Yu Lihong Xu Songping Yu Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration Ecology and Nature Conservation InstituteChinese Academy of ForestryBeijing100091China School of Soil and Water Conservation Beijing Forestry UniversityBeijing100083China

Background:Integrated forest-water management focusing on forest-water coordination is an important way to alleviate water use conflicts among forests and other sectors in vast dryland regions.Forest floor evapotranspiration(FE),which is an important component of forest evapotranspiration,accounts for a large proportion of the water consumed in arid forests.Elucidating how environmental and canopy conditions impact FE has important significance for guiding integrated forest-water management in a changing environment.Methods:The microlysimeter(ML)-measured evapotranspiration(FE_(ML)),reference evapotranspiration(ET_(o)),volumetric soil moisture(VSM),and canopy leaf area index(LAI)were monitored in a Larix principis-rupprechtii plantation located in the semi-humid liupan Mountains of Northwest China in 2019(June–September)and 2021(May–September).The response functions of the FE coefficient(the ratio of daily FEML to ET_(o))to the individual factors of VSM and LAI were determined using upper boundary lines of scatter diagrams of measured data.The framework of the daily FE(FE_(ML))model was established by multiplying the response functions to individual factors and then calibrated and validated using measured data to assess the FE response to environmental and canopy conditions.Results:(1)The FE coefficient increased first rapidly and then slowly with rising VSM but decreased slowly with rising LAI.(2)The simple daily FE(FE_(ML))model developed by coupling the impacts of ET_(o),LAI,and VSM in this study performed well for predicting FE.(3)The impacts of ET_(o),LAI,and VSM were quantified using the FE(FE_(ML))model,e.g.,at a given VSM,the impact of ETo on FE increased obviously with decreasing LAI;at a given ET_(o),the impact of LAI on FE increased with rising VSM.(4)In the two study years,when directly using the microlysimeter measurement,the real FE on the forest floor was overestimated when the VSM in microlysimeters was above 0.215 but underestimated below 0.215 due to the difference in VSM from the forest floor.T

关键词： Larch plantation Forest floor evapotranspiration Reference evapotranspiration Soil water content Canopy structure

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Modelling the response of larch growth to age,density,and elevation and the implications for multifunctional management in northwest China

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林业研究:英文版 2023年第5期34卷 1423-1436页

作者： Ao Tian Yanhui Wang Ashley A.Webb Pengtao Yu Xiao Wang zebin liu Institute of Mountain Resource of Guizhou Province Guiyang 550001People’s Republic of China Ecology and Nature Conservation Institute Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland AdministrationChinese Academy of ForestryBeijing 100091People’s Republic of China WaterNSW TamworthNSWAustralia

Plantations of Rupprecht's larch(Larix principis-rupprechtii)have been widely established in the drylands of northwest and north China under traditional fastgrowing plantation management strategies.These strategies and the long-term logging ban have led to over-populated stands with lower structural and functional stability,less economic benefit and higher water consumption.To guide the sustainable management of larch plantations,field surveys and historical data compilation were undertaken in the liupan Mountains of northwest China.The main influencing factors(stand structure and site condition)and their effects on mean tree height,mean DBH and timber volumes were determined based on up-boundary line analysis.Tree growth models coupling the effects of tree age,stand density,and elevation were established.Both height and DBH markedly increased initially and then slowly with tree age,decreased with stand density,and showed unimodal change with elevation.The coupled growth models accounted for72-78%of the variations in tree height,DBH and timber growth.Recommendations for future plantation management are:(1)prolong the rotation to at least 60 years to produce large-diameter,high-quality timber and maintain greater carbon stocks;(2)zone the target functions of stands by elevation;and,(3)reduce stand density for balanced supply of multiple ecosystem services.The growth models developed can predict growth response of larch plantations to density alteration under given ages and elevations,and assist the transformation from traditional management for maximum timber production to site-specific and multifunctional management with longer rotations and moderate tree density.

关键词： Larch plantations Coupled growth model Influencing factors Age Density Elevation

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Impacts of environmental and canopy conditions on the nighttime sap flow of larch plantations in the liupan Mountains,China

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林业研究:英文版 2023年第6期34卷 1927-1940页

作者： Songping Yu Jianbin Guo zebin liu Yanhui Wang Lihong Xu Pengtao Yu Liang He School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083People’s Republic of China Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration Ecology and Nature Conservation InstituteChinese Academy of ForestryBeijing 100091People’s Republic of China

Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions are of significance for arid area forest and water management.This study measured daily sap flow(Q_(s))of a Larix principis-rupprechtii plantation in the liupan Mountains,northwest China during the 2017-2019 growing seasons,and separated Q_(s)into daytime sap flow(Qd)and Q_(n).Meteorological conditions(reference evapotranspiration,ETref),canopy structure(leaf area index,LAI),and soil moisture(relative soil water content,RSWC)were considered as the main biophysical factors affecting Q_(n).The structural equation model and upper boundary line method determined the effects of compound and single factors on Q_(n)The daily mean Q_(n)values during the growing seasons in 2017,2018,and 2019 were 0.024,0.026,and 0.030 mm d-1,accounting for 6.2,11.2,and 10.1%of Q_(s),respectively.Q_(n)at different canopy development phases(leaf expanding,LG;leaf expanded,LD;and defoliation,DF)over three years was LD>LG>DF.Q_(n)increased with increasing ETref,whereas the ratio of Q_(n)to Q_(s)decreased.Q_(n)did not show regular variation in the three-year growing seasons under different soil moisture conditions.ETrefand LAI mainly controlled Q_(n)by affecting Qd,whereas RSWC had no significant effect on Q_(n).Q_(n)had a positive and linear relationship with LAI and a quadratic relationship with ETref.Both explained 40%of variation in Q_(n)Meteorological and canopy conditions are important factors affecting Q_(n)on the semi-humid study site.The application of the Q_(n)model coupled with the impact of ETrefand LAI furthers understanding of the impacts of climate and forest structure change on Q_(n).

关键词： Nighttime sap flow Reference evapotranspiration Leaf area index Soil moisture Multifactor impact

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具有尖锐吸收截面和显著增强电场的等离激元-光子混合谐振腔

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光子学报 2024年第5期53卷 215-224页

作者：刘莹朱泽斌蒋立勇南京理工大学物理学院微纳光子学与量子调控研究所南京210094 南京理工大学半导体微纳结构与量子信息感知工业和信息化部重点实验室南京210094

研究了由二维光子晶体微腔和金纳米天线组成的等离激元-光子混合谐振腔中光学谐振腔对等离激元谐振腔的额外贡献。研究结果表明:与纯等离激元谐振腔相比,混合体系的吸收截面和电场强度均明显增强。特别地,混合谐振腔的吸收截面谱呈现出... 详细信息

研究了由二维光子晶体微腔和金纳米天线组成的等离激元-光子混合谐振腔中光学谐振腔对等离激元谐振腔的额外贡献。研究结果表明:与纯等离激元谐振腔相比,混合体系的吸收截面和电场强度均明显增强。特别地,混合谐振腔的吸收截面谱呈现出类Fano线形和尖峰,可以通过改变金纳米天线的数量或金纳米天线与光子晶体微腔之间的共振波长失谐进行调制。此外,混合谐振腔的电场增强因子比金纳米天线高出3个数量级。可为光热探测和光谱增强研究提供新的平台。

关键词：混合谐振腔尖锐吸收截面显著增强电场表面等离激元光子晶体

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SEM imaging of insulating specimen through a transparent conducting veil of carbon nanotube

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Nano Research 2022年第7期15卷 6407-6415页

作者： Xinyu Gao Guo Chen He Ma Yuchen Ju Ke Zhang Lin Cong Wen Ning Zi Yuan zebin liu Lina Zhang Peng liu Shoushan Fan Kaili Jiang State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics and Tsinghua-Foxconn Nanotechnology Research CenterTsinghua UniversityBeijing 100084China College of Applied Sciences Beijing University of TechnologyBeijing 100124China Frontier Science Center for Quantum Information Beijing 100084China Beijing Advanced Innovation Center for Future Chips Beijing 100084China

Observing the morphology of insulating specimen in scanning electron microscope(SEM)is of great significance for the nanoscale semiconductor devices and biological tissues.However,the charging effect will cause image distortion and abnormal contrast when observing insulating specimen in SEM.A typical solution to this problem is using metal coating or water-removable conductive coating.Unfortunately,in both cases the surface of the specimen is covered by a thin layer of conductive material which hides the real surface morphology and is very difficult to be completely removed after imaging.Here we show a convenient,residue-free,and versatile method to observe real surface morphology of insulating specimen without charging effect in SEM with the help of a nanometer-thick film of super-aligned carbon nanotube(SACNT).This thin layer of SACNT film,like metal,can conduct the surface charge on insulating specimen through the sample stage to the ground,thus eliminating the charging effect.SACNT film can also be used as the conductive tape to carry and immobilize insulating powder or particles during SEM imaging.Different from the metal coating,SACNT film is transparent,so that the real microstructure of the insulating specimen surface can be observed.In addition,SACNT film can be easily attached to and peeled off from the surface of specimen without any residue.This convenient,residue-free,and versatile method can open up new possibilities in nondestructive SEM imaging of a wide variety of insulating materials,semiconductor devices,and biological tissues.

关键词： insulating specimen scanning electron microscope(SEM) super-aligned carbon nanotube(SACNT)film real morphology residue-free non-destructive imaging

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基本公共体育服务标准化推动健康国家建设:域外经验与本土镜鉴

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上海体育大学学报 2024年第7期48卷 15-30页

作者：胡庆山姚泽滨刘璐华中师范大学体育学院湖北武汉430079

对美、英、日三国基本公共体育服务标准化推动健康国家建设的政策、特征及经验进行研究,认为:美、英、日等发达国家率先开展了以基本公共体育服务标准化推动健康国家建设的顶层设计并各具政策特色,呈现权益保障均等化、治理主体多元化... 详细信息

对美、英、日三国基本公共体育服务标准化推动健康国家建设的政策、特征及经验进行研究,认为:美、英、日等发达国家率先开展了以基本公共体育服务标准化推动健康国家建设的顶层设计并各具政策特色,呈现权益保障均等化、治理主体多元化和校社资源一体化等共性特征,形成定性表述与定量要求相结合的标准化指标制定、政府主导与社会参与相结合的标准化政策实施、客观测量与主观评价相结合的标准化绩效评价、宏观调控与微观规制相结合的标准化治理架构等共同经验。结合域外经验及本土问题提出建议:细化标准指标制定,推动健康服务高质量发展;强化标准协同实施,推进健康保障持续性完善;规范标准绩效评价,促进健康监督全方位升级;优化标准执行架构,助力健康公平精细化治理。

关键词：基本公共体育服务标准化均等化健康国家健康中国发达国家

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基于多方向自适应感知网络的高光谱遥感图像分类

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遥感学报 2024年第1期28卷 168-186页

作者：刘倩吴泽彬徐洋郑鹏郑尚东韦志辉南京理工大学计算机科学与工程学院南京210014

高光谱遥感能够同步获取目标场景的光谱数据和空间图像,满足对目标物体成分组成和形貌特征的探测需求,已被广泛应用于精准农业、地质勘察、环境监测和生物医学等领域。近几年,得益于优秀的空谱信息表征能力,基于卷积神经网络的高光谱图... 详细信息

高光谱遥感能够同步获取目标场景的光谱数据和空间图像,满足对目标物体成分组成和形貌特征的探测需求,已被广泛应用于精准农业、地质勘察、环境监测和生物医学等领域。近几年,得益于优秀的空谱信息表征能力,基于卷积神经网络的高光谱图像分类方法取得了优于传统方法的分类精度。然而,基于一定规则和固定方形窗口的卷积运算无法满足不同对象、不同分布的空谱特征提取需求,当像素位于类别边缘时该模式无法避免其他类别的无关信息,导致类别间的信息扩散以及跨类别像素的误分和错分。针对上述问题,本文提出了一种基于多方向自适应感知的高光谱图像空谱联合分类方法,并通过联合不同邻域范围的空谱上下文信息来改善模型的局部空谱建模能力。具体研究过程如下:首先,将常规卷积网络的全窗口滤波器拆分为不同方向的半窗滤波器,从而设计出侧窗卷积以捕捉具有方向性的空谱特征;然后,在此基础上进一步将不同方向的侧窗滤波核整合到统一的卷积架构中构造空谱分离多方向卷积,并设计方向自适应感知模块,以密集连接构建基于高光谱图像的多方向自适应感知分类网络,赋予模型自适应学习多种空谱结构特征的能力,弥补常规卷积和侧窗卷积只能建模单一方向空谱关系的不足,提升模型对复杂空谱结构的刻画能力。在3个公开数据集上的实验结果表明,本文提出的多方向自适应感知分类方法较常规卷积方法具有更优的分类性能,能增强边缘样本的表征准确性,改善分类中的边缘混淆现象。

关键词：遥感高光谱图像深度学习多方向自适应感知空谱结构建模空谱联合分类

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Variations in stem radii of Larix principis-rupprechtii to environmental factors at two slope locations in the liupan Mountains,northwest China

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Journal of Forestry Research 2021年第2期32卷 513-527页

作者： Jing Ma Jianbin Guo Yanhui Wang zebin liu Di Gao liu Hong Ziyou Zhang School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083People’s Republic of China The Research Institute of Forest Ecology Environment and ProtectionChinese Academy of ForestryBeijing 100091People’s Republic of China

Relationships between stem growth and climatic and edaphic factors,notably air temperatures and soil moisture for different slopes,are not completely understood.Stem radial variations were monitored at the bottom and top slope positions in a Larix principis-rupprechtii plantation during the 2017 and 2018 growing seasons.Total precipitation during the growing season in 2017 and 2018 was 566 mm and 728 mm,respectively.Stem contractions typically occurred after mid-morning followed by swelling in the late afternoon in both plots,reflecting the diurnal cycle of water uptake and loss.Trees at the two locations showed the same growth initiation(mid-May)because of the small differences in air and soil temperatures.There were no significant differences in cumulative stem radial growth between the bottom plot(1.57±0.34 mm)and the top plot(1.55±0.26 mm)in 2018.However,in 2017,the main growth period of the bottom plot ceased 17 days earlier than in the top plot,while cumulative seasonal growth of the bottom plot(1.08±0.25 mm)was significantly less than the top plot(1.54±0.43 mm).Maximum daily stem shrinkage was positively correlated with air and soil temperatures,solar radiation,vapor pressure deficits,and negatively correlated with volumetric soil moisture content.The maximum daily shrinkage reflected transpiration rates as affected by environmental factors.Daily radial stem increment was correlated with precipitation and volumetric soil moisture in both years,but with air temperatures only in 2017.The seasonal growth of L.principis-rupprechtii Mayr thus shows interannual dynamics,while precipitation constitutes a key driving factor.

关键词： Stem radial variations Main growth period Diurnal patterns Initiation temperatures Meteorological factors Larix principis-rupprechtii plantation

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