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Calculating soil moisture by remote sensing and analyzing hydrologic cycle process in the Yellow River basin

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Science china(Technological Sciences) 2004年第Z1期47卷 1-13页

作者： YANG Shengtian1.& liu changming1, {1.1. School of Environmental Sciences, beijing {{1. university, beijing 100875, china {1. Institute of Geographic Science and Natural Resources Research, beijing 1.01.1. china School of Environmental Sciences Beijing Normal University Beijing China Institute of Geographic Science and Natural Resources Research Beijing China

Based on the AVHRR pathfinder remote sensing data, soil moisture, precipitation and evaporation during the period of 1.82.1.98, soil moisture of all layers of soil-profile (0—1.m) in the Yellow River basin over the 1. years are calculated by the remote sensing model of calculating soil water. The Yellow River basin is divided into seven subcatchments as control sections at the location of six hydrologic stations (Lanzhou, Toudaoguai, Longmen, Sanmenxia, Hua{1.ankou and Lijin). After calculating soil moisture and obtaining runoff data and precipitation data, the dynamical features of hydrological cycle in the Yellow River basin are analyzed for the period from 1.82.to 1.88 using water balance method. The conclusions are as follows: It is feasible to calculate the soil water on the macro-scale, in the soil profile with temporal continuity by means of remote sensing and survey in land. Some values of the key water cycle factors in the Yellow River are obtained, which include the annual precipitation of 4000 km3, the evapotranspiration of 3000-3500 km3, and the soil moisture transformation of ?500- 500 km3. Consequently, we analyzed the process of the water cycle in the Yellow River over the 1. years, and the results show that the segment upstream of Lanzhou city is a relatively humid region, and the area of internal waters and the reaches of Shanshan is the most desiccated region. Therefore, the runoff in the depth process is intensive and the runoff-generating process is weak in more arid regions.

关键词： the Yellow River, soil moisture, remote sensing, hydrologic cycle.

Investigation on the vortical structures by the liutex method in turbulent channels at Re_(τ)=1.0 with scalloped and triangular riblet control

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Journal of Hydrodynamics 2024年第1期36卷 35-52页

作者： Zhang-dan yu Shang {1. Hai-dong yu Bi-yu Pang Xin Dong Yi-qian wang School of Mathematical Sciences Soochow UniversitySuzhou215006China beijing Institute of Astronautical System Engineering Beijing100076China

Riblets are a series of small protrusions formed along the flow direction,which have been extensively studied as a passive turbulent drag reduction *** and numerical simulations have shown that well-designed riblets can significantly reduce drag in turbulent flows,making them highly promising and valuable for various *** this study,we focus on a scalloped riblet,which is designed by smoothly connecting two third-order polynomials,and thus the sharpness of the tip and the curvature of the valley can be well *** conduct direct numerical simulations of turbulent channel with smooth plate,scalloped riblet-mounted and triangular riblet-mounted *** in wall units of W^(+)=2. and height-width ratio ofγ=0.5 are selected for both riblet *** with the smooth plate case,the scalloped riblet case achieves an 8.68%drag reduction,while the triangular riblet case achieves a 4.79%drag *** obtained drag reduction rate of the triangular riblet is consistent with previous experiments and simulations,and the results indicate that the scalloped riblet is more effective in reducing drag and deserves further *** compare turbulent statistics of the scalloped riblet case with those of the triangular riblet *** mean velocity profiles of riblets are similar,but both the Reynolds shear stress and second-order statistics of velocity fluctuations and {1.tex are significantly reduced in the scalloped riblets controlled turbulent channel,indicating that the scalloped riblet can more effectively suppress the spanwise and wall-normal turbulent intensity near the *** also compare the pre-multiplied spectra of streamwise velocity and streamwise {1.tex component for the three cases to investigate the energy distribution and characteristics of {1.tex *** {1.tex vortex identification method is also utilized to analyze the instantaneous flow field,which provides insights into the flow field and could be bene

关键词： liutex vector riblet drag reduction tip sharpness turbulent channel scalloped

Polyoxometalate as the assembly material to self-assembled Ni(OH)_(2. nanosheets with electrocatalytic performance

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Nano Research 2024年第8期17卷 7061-7067页

作者： Danyang He Tianyang Li Luozhen jiang Fei {1. Zihao Xing Nan {1. Zhiyu Jia Guo-yu Yang Key Laboratory of Cluster Science Ministry of EducationSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China Shanghai Advanced Research Institute Chinese Academy of ScienceShanghai 201210China Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education Facluty of ChemistryNortheast Normal UniversityChangchun 130024China

Developing non-noble metal-based electrocatalyst with high catalytic activity is essential for advancing hydrogen energy *** study introduces a hydrothermal method for synthesizing order Ni(OH)_(2. nanosheets,with H_(3)O_(40)PW_(1.0}(denoted as PW_(1.0})loaded onto reduced graphene oxide(rGO)coated on nickel foam(referred to as PW_(1.0}-Ni(OH)_(2./rGO).This method contrasts with the electrodeposition of Ni(OH)_(2.,where PW_(1.0} is added to the synthetic system to direct the assembly and morphology of the Ni(OH)_(2. through a hydrothermal *** this work,the nickel foam acts dual roles as both the substrate and the source of nickel for the formation of Ni(OH)_(2..The PW_(1.0}-Ni(OH)_(2./rGO nanosheets,when successfully prepared and loaded onto the nickel foam(NF),exhibited superior electrocatalytic activity for the hydrogen evolution reaction(HER)in an alkaline electrolyte,achieving a current density of 1. mA·cm^(-2. at an overpotential of 69 ***,we endeavored to expand the application of this material towards the oxygen evolution reaction(OER)by preparing PW_(1.0}-(Fe/Co)Ni(OH)_(2./rGO through the addition of metal *** nanocomposite displayed outstanding electrocatalytic activity in alkaline electrolytes,with a current density of 1. mA·cm^(-2.at an overpotential of 2.1.mV,and demonstrated excellent stability over a 50 h period in a 1.M KOH *** results presented in this paper offer an effective strategy for the preparation of polyoxometalate-based inorganic materials with diverse functionalities,applicable to both HER and OER.

关键词： polyoxometalate Ni(OH)_(2. assembly hydrogen evolution reaction oxygen evolution reaction

A distributed hydrological model with its application to the Jinghe watershed in the Yellow River Basin

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Science china(Technological Sciences) 2004年第Z1期47卷 60-71页

作者： wang Zhonggen1, ZHENG Hongxing1, liu changming1, , WU Xianfeng2.2.& ZHAO Weimin3 1. Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, {2. 100101, china 2. Institute of Environmental Science, {2. normal university, beijing 100875, china 3. Water Resources Conservation Committee of Yellow River, Zhengzhou 450003, china Key Laboratory of Water Cyde & Related Land Surface Processes Institute of Geographic Science and Natural Resources Research Chinese Academy of Sciences Beijing China Institute of Environmental Science Beijing Normal University Beijing China Water Resources Conservation Committee of Yellow River Zhengzhou China

For the purpose of water resources management in the Yellow River Basin with highly spatial difference, a daily distributed hydrological model was proposed, of which the determination of spatially-distributed parameters and model inputs processing were performed by means of GIS/RS. In the model, the computation of runoff yield was based on the topography index method and flow routing was modeled by Maskingum method. The operation of the model is followed by means of “command structure” technique based upon the topography of river network. A case study using the model was conducted for the Jinghe watershed, which locates at the middle Yellow River Basin. The simulation of the hydrological processes in 1.96 has shown that water quantity balance errors were less than 5% and the Nash-Sutcliffe coefficient arrived at 0.7, indicating that the model structure is justifiable, and the precision of the model can satisfy the purpose of water resources management.

关键词： distributed hydrological model, structure and equation, GIS and RS, Jinghe Basin, Yellow River Basin.

Refining the Factors Affecting N_(2.O Emissions from Upland Soils with and without Nitrogen Fertilizer Application at a Global Scale

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Advances in Atmospheric Sciences 2024年第9期41卷 1804-1820页

作者： Wenqian jiang Siqi LI Yong LI Meihui {1. Bo {1. Ji liu Jianlin SHEN Xunhua ZHENG State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Key Laboratory for Agro-ecological Processes in Subtropical Regions Institute of Subtropical AgricultureChinese Academy of SciencesChangsha 410125China Changsha Research Station for Agricultural&Environmental Monitoring Chinese Academy of SciencesChangsha 410125China university of Chinese Academy of Sciences Beijing 100049China State Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Pollution Complex Shanghai Academy of Environment SciencesShanghai 200233China Institute of Carbon Neutrality Qilu ZhongkeJinan 251699China Hubei Province Key Laboratory for Geographical Process Analysis and Simulation Central China Normal UniversityWuhan 430079China Department of Ecohydrology Leibniz Institute of Freshwater Ecology and Inland FisheriesBerlin 12587Germany Key laboratory of Environment Change and Resources Use in Beibu Gulf Ministry of EducationNanning Normal UniversityNanning 530001China Golden Mantis school of Architecture Soochow UniversitySuzhou 215123China

Nitrous oxide(N_(2.O)is a long-lived greenhouse gas that mainly originates from agricultural *** and more studies have explored the sources,influencing factors and effective mitigation measures of N_(2.O in recent ***,the hierarchy of factors influencing N_(2.O emissions from agricultural soils at the global scale remains *** this study,we carry out correlation and structural equation modeling analysis on a global N_(2.O emission dataset to explore the hierarchy of influencing factors affecting N_(2.O emissions from the nitrogen(N)and non-N fertilized upland farming systems,in terms of climatic factors,soil properties,and agricultural *** results show that the average N_(2.O emission intensity in the N fertilized soils(1..83 g N ha^(-1.d^(-1.)was significantly greater than that in the non-N fertilized soils(5.34 g N ha^(−1. d^(−1.)(p1..Climate factors and agricultural practices are the most important influencing factors on N_(2.O emission in non-N and N fertilized upland soils,*** different climatic zones,without fertilizer,the primary influence factors on soil N_(2.O emissions are soil physical properties in subtropical monsoon zone,whereas climatic factors are key in the temperate *** fertilizer,the primary influence factors for subtropical monsoon and temperate continental zones are soil physical properties,while agricultural measures are the main factors in the temperate monsoon *** enhanced agricultural practices,such as reduced N fertilizer rate combined with the addition of nitrification and urease inhibitors can potentially mitigate N_(2.O emissions by more than 60%in upland farming systems.

关键词： N_(2.O emissions influencing factors nitrogen cycling upland farming systems

Spatio-temporal pattern analysis of single-trial EEG signals recorded during visual object recognition

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Science china(Information Sciences) 2011年第12期54卷 2519-2527页

作者： wang {1. 1., HU XiaoPing 3 , YAO Li 1.2., XIONG Shi 2.& ZHANG JiaCai 2.1.National Key Laboratory of Cognitive Neuroscience and Learning, {2. normal university, beijing 100875, china 2.College of Information Science and Technology, {2. normal university, beijing 100875, china 3 Biomedical Imaging Technology Center, Emory university/Georgia Institute of Technology, Atlanta 3032., USA National Key Laboratory of Cognitive Neuroscience and Learning Beijing Normal University Beijing China Biomedical Imaging Technology Center Emory University/Georgia Institute of Technology Atlanta USA College of Information Science and Technology Beijing Normal University Beijing China

Object discrimination is a fundamental cognitive function for human brains. In this study, we utilized an analysis approach for single-trial electroencephalography (EEG) to analyze the spatio-temporal activation patterns of visual objects processing in human brains, and attempted to apply it to discriminate different visual objects. The spatial patterns were respectively extracted from scalp EEG and the reconstructed cortical sources, while the experiment participants were perceiving 4 different categories of visual objects (faces, buildings, cats and cars). By classifying the patterns extracted from single-trial EEG, the presented visual objects could be discriminated by a computer, and the classification accuracies may provide a quantitative index to evaluate the spatial differences of the brain activations related to different visual objects. Our results demonstrated that the spatial patterns on both the scalp and the sources levels resulted in higher classification accuracies than chance rate. We also examined the classification results using temporally non-overlapping time intervals of different event-related potential (ERP) components. The temporal changes of classification accuracies may reflect the temporal distribution of the discriminative information in the EEG responses. The present pattern extraction and classification methods may compose a computational model for single-trial EEG data analysis in investigations of the spatio-temporal activation patterns for object recognition. These spatio-temporal patterns in EEG may be useful to identifying the discriminative spatial areas and time stages to improve the accuracies and efficiencies of object discrimination. In addition, investigating and utilizing humans'cognitive mechanisms of object recognition may improve computers' processing efficiency of visual information.

关键词： EEG spatio-temporal pattern object recognition single-trial analysis visual information processing

Co/N co-doped flower-like carbon-based phase change materials toward solar energy harvesting

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Aggregate 2024年第1期5卷 321-330页

作者： Xiao Chen Lei wang Yan Gao Yang Li Xiaowei Zhang {1. jiang Ge wang Institute of Advanced Materials Beijing Normal UniversityBeijingChina beijing Advanced Innovation Center for Materials Genome Engineering Beijing Key Laboratory of Function Materials for Molecule and Structure ConstructionSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijingChina

The photothermal conversion capacity of pristine organic phase change materials(PCMs)is inherently insufficient in solar energy *** upgrade their photothermal conversion capacity,we developed bimetallic zeolitic imidazolate framework(ZIF)derived Co/N co-doped flower-like carbon(Co/N-FLC)-based composite PCMs toward solar energy harvesting.3D interconnected carbon framework with low interfacial thermal resistance,abundant carbon defects and high content of nitrogen doping,excellent localized surface plasmon resonance(LSPR)effect of Co nanoparticles,and light absorber Co_(3)ZnC in Co/N-FLC synergistically upgrade the photothermal capacity of(polyethylene glycol)PEG@Co/N-FLC composite PCMs with an ultrahigh photothermal conversion efficiency of 94.8%under 0.1. W/cm^(2..Uniformly anchored Co and Co_(3)ZnC nanoparticles in carbon framework guarantee excellent photon capture *** carbon nanotubes(CNTs)in 2. carbon nanosheets further accelerate the rapid transport of phonons by constructing cross-connected heat transfer ***,PEG@Co/N-FLC exhibits a thermal energy storage density of 1.0.69 J/g and excellent thermal stability and durable ***,PEG@Co/N-FLC composite PCMs are promising candidates to accelerate the efficient utilization of solar energy.

关键词： bimetallic ZIF Co/N co-doped carbon phase change materials photothermal conversion thermal energy storage

Quasi-critical ring of a primitive ring with nonzero socle

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Chinese Science Bulletin 1997年第3期42卷 189-192页

作者： jiang ZimeiDepartment of Mathematics, {1. {2. university, beijing 100875, china Department of Mathematics Beijing Normal University Beijing China

IN ref. [1. Jacobson proved the structure theorem for primitive rings with nonzero socles that R is a primitive ring withsocle S≠1. if and only if there is a pair of dual vector spaces (M,M’) over a division ring ... 详细信息

IN ref. [1. Jacobson proved the structure theorem for primitive rings with nonzero socles that R is a primitive ring withsocle S≠2. if and only if there is a pair of dual vector spaces (M,M’) over a division ring Δ such that S=F(M, M’)(?) R(?)(?)(M, M’), where (?)(M, M’)-{ω∈Ω|ωM’(?)M’, Ω is the complete ring of linear transformations of M over Δ}, F(M, M’) is the set of all linear transformations of (?)(M, M’) of finite rank. After that, some people reproved this theorem by using different methods such as those in refs. [2. 3]. In

关键词： primitive ring socle conjugate space total subspace of conjugate space.

Synthesis of spherical nano-ZSM-5 zeolite with intergranular mesoporous for alkylation of ethylbenzene with ethanol to produce m-diethylbenzene

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Chinese Journal of Chemical Engineering 2024年第3期67卷 298-309页

作者： Siyue {1. Jinhong Li Qingxin Xu Shengjie Song yu'ni jiang Lidong Chen Xin Shi Weiguo Cheng Faculty of Chemistry and Chemical Engineering Liaoning Normal UniversityDalian 110629China beijing Key Laboratory of Ionic Liquids Clean Process Key Laboratory of Green Process and EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China

Catalytic synthesis of m-diethylbenzene(m-DEB)through alkylation of ethylbenzene(EB)may be a promising alternative route in comparison with traditional rectification of mixed DEB,for which the top priority is to develop efficient and stable heterogeneous ***,the spherical nano-ZSM-5 zeolite with abundant intergranular mesoporous is synthesized by the seed-mediated growth method for alkylation of EB with ethanol to produce *** results show that the spherical nano-ZSM-5 zeolite exhibits better stability and higher alkylation activity at a lower temperature than those of commercial micropore *** then,the spherical nano-ZSM-5 is further modified by La_(2.O_(3) through acid treatment followed by immersion *** acid treatment causes nano-ZSM-5 to exhibit the increased pore size but decreased the acid sites,and subsequent La_(2.O_(3) loading reintroduces the weak acid *** a result,the HNO_(3)-La_(2.O_(3)-modified catalyst exhibits a slight increase in EB conversion and DEB yield in comparison with unmodified one,and meanwhile,it still maintains high m-DEB *** catalyst after acid treatment achieves higher catalytic stability besides maintaining the high alkylation activity of EB with *** present study on the spherical nano-HZSM-5 zeolite and its modification catalyst with excellent alkylation ability provides new insights into the production of mDEB.

关键词： Zeolite Modification Alkylation reaction m-diethylbenzene Catalyst Fixed-bed