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

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 experiments.Four contrasting soils as sandy loam,sandy clay loam,clay loam and loamy clay were collected from different parts of the loess Plateau.The results showed that sediment load was significantly impacted by soil properties in all three sub-processes.Splash 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 duration.The 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 soil.The 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 Plateau.The 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 content.The impacts of slope gradient on the runoff rate and sediment load also changed with soil properties.The 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 erosion.Based 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 gradient.The findings from this study should support the improvement of erosion prediction and cropland management in different

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

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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 materials.Up to date,the formation mechanisms of the key strengthening precipitates,namedθ’-phase,in the alloys are still controversial.Here,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 structures.Atomicresolution 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 Al-lattice.This 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 structure.Our 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

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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 profoundly.Many countries have launched COVID-19 mobile apps with a wide range in how these apps work.While it is hoped that these apps can assist in the fight against COVID-19,many are worried about user privacy.China implemented“health code”systems,which assigned neighborhoods and citizens a specific health code,meant to indicate their risk of having been exposed to COVID-19.The most widely used health code systems were hosted on the popular apps WeChat and Alipay,each with billions of users.Some experts argued that China’s use of mobile applications was essential to its successful combat against COVID-19.Included 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 imple-mented.Also 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 COVID-19.The interviews revealed four important themes:personal privacy,community involvement,government involvement,and situational speci-ficity.It was found that a key concern was maintaining a balance between collecting and utilizing personal information,as well as protecting this information.In addition,close collaboration between local communities and the national government was essential.Mobile applications assisted in communication and coordination but did not replace the work of people such as delivery drivers and contact tracers.Our results also showed that there was room for improvement,especially accessibility for the elderly or those unfamiliar with technology.Similar results were obtained from our survey.It 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 feature of COVID-19 apps.Both interview and survey res

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

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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 composites.The factors influencing the effective thermal conductivity of the GNP/Al composites were investigated,including the orientation,shape,aspect ratio,configuration and volume fraction of GNPs.The 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 conductivity.In addition,with increasing the aspect ratio of GNPs,the thermal conductivity of GNP/Al composites increases and finally tends to be stable.The 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 configurations.The effective thermal conductivity is sensitive to volume fraction of GNPs.Ideally,when the volume fraction of layered GNPs reaches 1.54%,the thermal conductivity of GNP/Al composites is as high as 400 W/m K.The 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

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A SIMUlATION STUDY OF DEPOSITION UNDER TWO TYPES OF IMPINGING TRAJECTORIES

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Acta Metallurgica Sinica(English letters) 2004年第6期17卷 876-880页

作者： X.Q.Wei L.Zhou SchoolofMaterialsScience＆Engineering NanchangUniversityNanchang330047China

A model coupling particle aggregation and randomwalk surface diffusion has been developed for 2D simulation of depositional growth, in which impinging particles follow either a straight-line trajectory of cosine distribution, representing typically sputter deposition, or a scattered trajectory, representing typically electrochemical deposition. Simulations of the growth under various impinging conditions and effective surface diffusivity have been carried out. Pattern and defect development in deposition on flat, trenched and ridged substrates have been investigated. We found that on flat and ridged substrates, both types of trajectories yield similar features, including formation of cone-like defects on surface ridges. While on trenched substrate, the straight-line impingement yielded more uniform step coverage than the scattered impingement.

关键词： deposition simulation pattern formation ballistic model

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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

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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 determined.All 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,plinearity.The BC isolates 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 Phen.At a given Ce,the BC had higher Koc value than the original sediments,revealing a higher sorption capacity for BC.BC 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

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多参数MRI评估慢性肾病和肾纤维化的价值

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国际医学放射学杂志 2023年第5期 622-622页

作者： C.Hua l.Qiu L.Zhou Y.Zhuang T.Cai B.Xu 许振华

摘要目的确定评估慢性肾脏病（CKD）和肾间质纤维化（IF）的最佳MRI参数。方法前瞻性纳入43例CKD病人和20例正常对照组。CKD组根据病理检查结果分为轻度和

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

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

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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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汶川—芦山地震之间地震空区及邻区的微震时空分布特征及指示意义

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世界地震译丛 2019年第4期50卷 331-350页

作者： C.l.Wang C.T.liang K.Deng Y.l.Huang L.Zhou 王朝亮(译) 梁春涛(校) 不详成都理工大学地质灾害防治与地质环境保护国家重点实验室

在龙门山西南段,汶川和芦山两次地震之间地震空区产生的物理机制及其未来的地震活动性仍然是亟需进一步研究的问题。现有研究结果也无法完全解释地震空区挤压应变/应力的调节模式。我们使用Match and locate方法获取了2015年5月至12月... 详细信息

在龙门山西南段,汶川和芦山两次地震之间地震空区产生的物理机制及其未来的地震活动性仍然是亟需进一步研究的问题。现有研究结果也无法完全解释地震空区挤压应变/应力的调节模式。我们使用Match and locate方法获取了2015年5月至12月时段内空区及邻区的详细的背景地震目录,完备性震级为M_c=0.2,微震的时空分布特征凸显了小震级事件的丛集(簇)特征。在深度域上,微震在空区两端的优势深度存在明显差异,南端深于北端,表明空区作为汶川和芦山两次地震破裂的转换带。我们的微震探测结果表明空区存在明显的微震"亏空",否定了其通过微地震释放累积应力的调节模式。我们发现该区域内,不同震级范围内的背景地震活动性都与降雨变化率存在明显的反相关关系。在夏、秋季节,地震活动性极值滞后于降水极值1～2个月,库仑模型计算表明增强的地震活动性很可能被浅地表含水量的减少所触发,季节性降水在一定程度上调节了背景地震活动性。相较于震级大于3.0的背景地震,背景微震对降水的变化具有更敏感的响应,这可能由其更短的起始周期所致。

关键词：时空分布特征地震空区微震芦山汶川邻区地震活动性调节模式

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