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Comparing surface erosion processes in four soils from the loess Plateau under extreme rainfall events

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International Soil and Water Conservation Research 2021年第4期9卷 520-531页

作者： liying Sun John l.zhou Qiangguo Cai Suxia liu Jingan Xiao Key laboratory of Water Cycle and Related land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China School of Civil and Environmental Engineering University of Technology Sydney15 BroadwayNSW 2007Australia

This research aims to improve erosion control practice in the loess Plateau,by studying the surface erosion processes,including splash,sheet/interrill and rill erosion in four contrasting soils under high rainfall intensity(120 mm h^(−1))with three-scale indoor artificial *** contrasting soils as sandy loam,sandy clay loam,clay loam and loamy clay were collected from different parts of the loess *** results showed that sediment load was significantly impacted by soil properties in all three *** rate(4.0-21.6 g m^(−2∙)min^(−1))was highest in sandy loam from the north part of the loess Plateau and showed a negative power relation with the mean weight diameter of aggregates after 20 min of rainfall *** average sediment load by sheet/interrill erosion(6.94-42.86 g m^(−2∙)min^(−1))was highest in clay loam from middle part of the loess Plateau,and the stable sediment load after 20 min showed a positive power relation with the silt content in *** average sediment load increased dramatically by rill and interrill erosion(21.03-432.16 g m^(−2∙)min^(−1)),which was highest in loamy clay from south part of the loess *** average sediment load after the occurrence of rill showed a positive power relation with clay content and a negative power relation with soil organic matter *** impacts of slope gradient on the runoff rate and sediment load also changed with soil *** critical factors varied for different processes,which were the aggregate size for splash erosion,the content of silt particles and slope gradient for sheet/interrill erosion,and the content of clay particles,soil organic matter and slope gradient for rill *** on the results of the experiments,specific erosion control practices were proposed by targeting certain erosion processes in areas with different soil texture and different distribution of slope *** findings from this study should support the improvement of erosion

关键词： Soil erosion process Particle size Surface erosion Cropland management loess Plateau

NANOSIZE EFFECT IN GRAIN BOUNDARY MIGRATION OF COPPER

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Acta Metallurgica Sinica(English letters) 2004年第1期17卷 11-15页

作者： l.zhou X.Q.Wei N.G.zhou D.G.li School of Materials Science and Engineering Nanchang UniversityNanchang 330047ChinaSchool of Materials Science and EngineeringNanchang UniversityNanchang 330047ChinaSchool of Materials Science and EngineeringNanchang UniversityNanchang 330047ChinaCentral Iron and Steel Research InstituteBeijing 100083China

Molecular dynamics simulations of high temperature annealing of copper bicrystals have been carried out. The bicrystals have planar grain boundaries, and the gain size varies in nano range. An EAM (embedded atom method) potential of FS type is used for calculating the interatomic forces. The results show that in nanocrystalline copper, GB migration driven by inter-GB reaction can take place. A critical grain size is identified, below which the inter-GB reaction becomes strong enough to trigger GB motion, which accelerates rapidly and leads to annihilation of the grain boundaries. The critical size is found to be 16 atomic radii. A "through intermediate grain mechanism" is identified for the nano-grain boundary motion observed, which is never reported for GB migrations of conventional polycrystalline metals.

关键词： grain boundary migration nanocrystal copper

lessons on mobile apps for COVID-19 from China

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Journal of Safety Science and Resilience 2021年第2期2卷 40-49页

作者： Sophia l.zhou Xianhan Jia Samuel P.Skinner William Yang Isabelle Claude Mass Academy of Math and Science Worcester Polytechnic Institute85 Prescott StreetWorcesterMA 01605United States Department of Computer Science Worcester Polytechnic Institute100 Institute RoadWorcesterMA 01609United States Department of Physics Worcester Polythenic Institute100 Institute RoadWorcesterMA 01609United States Department of Biomedical Engineering Worcester Polytechnic Institute100 Institute RoadWorcesterMA 10609United States

The COVID-19 pandemic has impacted the global society and human life *** countries have launched COVID-19 mobile apps with a wide range in how these apps *** it is hoped that these apps can assist in the fight against COVID-19,many are worried about user *** implemented“health code”systems,which assigned neighborhoods and citizens a specific health code,meant to indicate their risk of having been exposed to *** most widely used health code systems were hosted on the popular apps WeChat and Alipay,each with billions of *** experts argued that China’s use of mobile applications was essential to its successful combat against *** in this study are a summary of mobile technology usage in China,a review of previous studies of mobile technology in healthcare,and a brief survey of some existing mobile applications for COVID-19 that were *** included are outcomes of interviews with healthcare and public safety experts and a public survey to understand how mobile applications were used in China’s response to *** interviews revealed four important themes:personal privacy,community involvement,government involvement,and situational *** was found that a key concern was maintaining a balance between collecting and utilizing personal information,as well as protecting this *** addition,close collaboration between local communities and the national government was *** applications assisted in communication and coordination but did not replace the work of people such as delivery drivers and contact *** results also showed that there was room for improvement,especially accessibility for the elderly or those unfamiliar with *** results were obtained from our *** was interesting to find that the apps were mostly used for“accessing information on COVID-19.”In addition,respondents overwhelmingly identified“information”as the most valuable featur

关键词： Mobile apps COVID-19 response Survey Interview lessons

Phenanthrene sorption to environmental black carbon in sediments from the Song-liao watershed(China)

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Frontiers of Environmental Science & Engineering 2009年第4期3卷 434-442页

作者： Jinghuan ZHANG Mengchang HE Chunye lIN Ke SUN Bin MEN John l.zhou State Key laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China

Black carbon(BC)in ten contaminated sediments from the Song-liao watershed,NE China,was isolated upon treatments using a combustion method at 375℃,and the isolates’sorption isotherms for phenanthrene(Phen)were *** sorption isotherms were nonlinear and fitted well by the Freundlich model.A negative relation was found between Freundlich sorption nonlinearity parameter(n values)and BC/total organic carbon(TOC)content of the original sediments(r^(2)=0.687,plates from this industrialized region had n values of 0.342 to 0.505 and logKFOC values of 6.02 to 6.42(μg·kg^(–1)·OC^(–1))/(μg·l^(–1))n for *** a given Ce,the BC had higher Koc value than the original sediments,revealing a higher sorption capacity for *** was responsible for 50.0%to 87.3%of the total sorption at Ce=0.05 Sw,clearly indicating the dominance of BC particles in overall sorption of Phen by sediments.

关键词： phenanthrene sorption black carbon sediment Song-liao watershed

A hidden precipitation scenario of theθ’-phase in Al-Cu alloys

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Journal of Materials Science & Technology 2021年第16期75卷 126-138页

作者： l.zhou C.l.Wu P.Xie F.J.Niu W.Q.Ming K.Du J.H.Chen center for high-resolution electron microscopy college of materials science and engineeringhunan universitychangshahunan410082china shenyang national laboratory for materials science institute of metal researchchinese academy of sciences.shenyan7.110016china

Al-Cu binary alloys are important and interesting industry *** to date,the formation mechanisms of the key strengthening precipitates,namedθ’-phase,in the alloys are still ***,we report that for non-deformed bulk Al-Cu alloys theθ’-phase actually has its own direct precursors that can form only at elevated aging temperature(>ca.200℃).These high-temperature precursors have the same plate-like morphology as theθ’-phase precipitates but rather different *** imaging reveals that they have a tetragonal structure with a=0.405 nm and c=1.213 nm,and an average composition of Al_(5-x)Cu_(1+x)(0≤xlly coherent with the *** precursor phase may initiate with a composition of Al5 Cu and evolve locally towards Al_(4)Cu_(2)in composition,eventually leading to a consequent structural transformation into theθ’-phase(Al4 Cu2=Al2 Cu).There are evidences that because of their genetic links in structure,such a high-temperature precursor may transform to theθ’-phase without having to change their morphology and interface *** study reveals a well-defined and previously hidden precipitation scenario for theθ’-phase to form in Al-Cu alloys at an elevated aging temperature.

关键词： AlCu alloy Age-hardening Precipitation Electron microscopy

Finite Element Prediction of the Thermal Conductivity of GNP/Al Composites

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Acta Metallurgica Sinica(English letters) 2022年第5期35卷 825-838页

作者： X.S.Yang l.zhou K.Y.liu Z.Y.liu Q.Z.Wang B.l.Xiao Z.Y.Ma School of Electromechanical and Automotive Engineering Yantai UniversityYantai264005China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

A 3 D multi-scale finite element model was developed to predict the effective thermal conductivity of graphene nanoplatelet(GNP)/Al *** factors influencing the effective thermal conductivity of the GNP/Al composites were investigated,including the orientation,shape,aspect ratio,configuration and volume fraction of *** results show that GNPs shape has a little influence on the thermal conductivity of GNP/Al composites,and composites with elliptic GNPs have the highest thermal *** addition,with increasing the aspect ratio of GNPs,the thermal conductivity of GNP/Al composites increases and finally tends to be *** GNPs configuration strongly influences the thermal conductivity of GNP/Al composites,and the thermal conductivity of the composites with layered GNPs is the highest among the five *** effective thermal conductivity is sensitive to volume fraction of ***,when the volume fraction of layered GNPs reaches 1.54%,the thermal conductivity of GNP/Al composites is as high as 400 W/m *** findings of this study could provide a good theoretical basis for designing high thermal conductivity GNP/Al composites.

关键词： Multi-scale finite element model Thermal conductivity GNP/Al composites Shape Aspect ratio Configuration

Study on the Pyrolysis Kinetics of Cotton Stalk based on the Multiscanning Method

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Study on the Pyrolysis Kinetics of Cotton Stalk based on the...

Influence of interplanetary magnetic field and solar wind on auroral brightness in different regions

International Conference on Industrial Technology and Management Science(ITMS 2015)

作者： l.zhou l.Y.WANG F.lIU J.l.SUN Z.Y.lI C.l.QIN School of Mechanical and Electrical Engineering Tarim University The Key laboratory of Colleges & Universities under the Department of Education of Xinjiang Uygur Autonomous Region

Cotton stalk pyrolysis behavior and mechanism were studied based on the multi-scanning method. The results showed that cotton stalk pyrolysis zone during 3000 ℃ could be divided into four regions, namely, water loss, depolymerization "glass transition", main pyrolysis and charring stage. During the main reaction zone TG curves and differential TG curves were moving to high temperature. The activation energy E of the main stage of pyrolysis was solved by FWO and FRl method respectively. The results showed that the activation energy E was very stable in the conversion rate of 10% to 70%. The results of the two solving methods were very close and had a high degree of linear fitting. Experimental data were analyzed by the non-linear fitting, and the mechanism of cotton stalk pyrolysis met Avrami-Erofeev equation. The reaction value of series(grade) was 0.4. The mechanism function forms are G(a) = [ -ln(1 -a)] and f(a) = 5/2(1-a)[ -ln(1-a)] respectively.

关键词： Cotton Stalk Multi-scanning Method Pyrolysis Mechanism Dynamics

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Influence of interplanetary magnetic field and solar wind on...

X-RAY STRUCTURE DETERMINATION OF SUBTIlISIN E AT 2 RESOlUTION

中国空间科学学会空间物理学专业委员会第十五届全国日地空间物理学研讨会

作者： Y.F.Yang J.Y.lu J.-S.Wang Z.Peng l.zhou National Center for Space Weather China Meteorological Administration State Key laboratory of Space Weather Center for Space and Applied ResearchChinese Academy of Sciences Science and Technology on Aerospace Flight Dynamics laboratory Beijing Aerospace Control Center

By integrating and averaging the auroral brightness from Polar Ultraviolet Imager auroral images,which have the whole auroral ovals,and combining the observation data of interplanetary magnetic field(IMF)and solar wind from NASA Operating Missions as a Node on the Internet(OMNI),we investigate the influence of IMF and solar wind on auroral activities,and analyze the separate roles of the solar wind dynamic pressure,density,and velocity on aurora,*** statistically analyze the relations between the interplanetary conditions and the auroral brightness in dawnside,dayside,duskside,and *** is found that the three components of the IMF have different effects on the auroral brightness in the different *** from the nightside auroral brightness,the dawnside,dayside,and duskside auroral brightness are affected by the IMF Bx,and By components more *** IMF Bx and By components have different effects on these three regional auroral brightness under the opposite polarities of the IMF *** expected,the nightside aurora is mainly affected by the IMF Bz,and under southward IMF,the larger the|Bz|,the brighter the nightside *** IMF Bx and By components have no visible *** the other hand,it is also found that the aurora is not intensified singly with the increase of the solar wind dynamic pressure:when only the dynamic pressure is high,but the solar wind velocity is not very fast,the aurora will not necessarily be intensified *** results can be used to qualitatively predict the auroral activities in different regions for various interplanetary conditions.

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X-RAY STRUCTURE DETERMINATION OF SUBTILISIN E AT 2 RESOLUT...