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The complementary graphene growth and etching revealed by large-scale kinetic Monte Carlo simulation

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npj Computational Materials 2021年第1期7卷 117-125页

作者： Xiao Kong Jianing Zhuang Liyan Zhu Feng Ding centre for Multidimensional Carbon Materials Institute for Basic ScienceUlsan 44919Korea Institute of Textiles and Clothing Hong Kong Polytechnic University999077 Kowloon Hong KongChina Department of Physics and Jiangsu Key Laboratory of Modern Measurement Technology and Intelligent SystemsHuaiyin Normal University223300 Huai’anChina School of Materials Science and Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Korea

To fully understand the kinetics of graphene growth,large-scale atomic simulations of graphene islands evolution up to macro sizes(i.e.,graphene islands of a few micrometers or with billions of carbon atoms)during growth and etching is essential,but remains a great challenge.In this paper,we developed a low computational cost large-scale kinetic Monte Carlo(KMC)algorithm,which includes all possible events of carbon attachments and detachments on various edge sites of graphene islands.Such a method allows us to simulate the evolution of graphene islands with sizes up to tens of micrometers during either growth or etching with a single CPU core.With this approach and the carefully fitted parameters,we have reproduced the experimentally observed evolution of graphene islands during both growth or etching on Pt(111)surface,and revealed more atomic details of graphene growth and etching.Based on the atomic simulations,we discovered a complementary relationship of graphene growth and etching—the route of graphene island shape evolution during growth is exactly the same as that of the etching of a hole in graphene and that of graphene island etching is exactly same as that of hole growth.The complementary relation brings us a basic principle to understand the growth and etching of graphene,and other 2D materials from atomic scale to macro size and the KMC algorithm is expected to be further developed into a standard simulation package for investigating the growth mechanism of 2D materials on various substrates.

关键词： sizes complementary island

Functional diversity dominates positive species mixture effects on ecosystem multifunctionality in subtropical plantations

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Forest Ecosystems 2022年第3期9卷 417-426页

作者： Xi Li Hui Wang Junwei Luan Scott X.Chang Bing Gao Yi Wang Shirong Liu Institute of Resources and Environment International Centre for Bamboo and RattanKey Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo&Rattan Science and TechnologyBeijing100102China Key Laboratory of Forest Ecology and Environment of national Forestry and Grassland Administration Ecology and Nature Conservation InstituteChinese Academy of ForestryBeijing100091China Department of Renewable Resources University of Alberta442 Earth Sciences BuildingEdmontonAlbertaT6G 2E3Canada

Mixed-species plantations generally exhibit higher ecosystem multifunctionality than monospecific plantations.However,it is unclear how tree species functional composition influences species mixture effects on ecosystem multifunctionality.We selected 171 monospecific and mixed-species plantations from nine regions across subtropical china,and quantified 13 key ecosystem functional properties to investigate how species mixture effects on ecosystem multifunctionality are modulated by functional diversity and identity.We found that ecosystem multifunctionality was significantly higher(p<0.05)in mixed tree plantations than in monospecific plantations except the mixed-conifer species plantations.Across all regions,ecosystem multifunctionality was significantly higher(p<0.05)in mixed conifer-broadleaf plantations than in monospecific plantations of the corresponding species,but not different between mixed and monospecific coniferous plantations.The magnitude of species mixture effects on ecosystem multifunctionality varied greatly with tree species compositions.Taking Cunninghamia lanceolata Lamb.as an example,the effects varied from a range of 2.0%–9.6%when mixed with a conifer species to 36%–87%when mixed with a broadleaf species.The functional diversity was the dominate driver shaping ecosystem multifunctionality,while functional identity,as expressed by community-weighted mean of specific leaf area,also had a positive effect on ecosystem multifunctionality through the increased below-ground nitrogen and phosphorus stocks regulated by specific leaf area of the mixing tree species.Our study highlights the important role of functional diversity in shaping ecosystem multifunctionality across region-wide environmental conditions.Mixed conifer-broadleaf tree plantations with distinct functional traits benefit the enhancement of ecosystem multifunctionality,and the magnitude of species mixture effects is modulated by the functional identity of tree species composition;those relationships deserve a special consideration in

关键词： Ecosystem multifunctionality Species mixture effects Functional diversity Functional identity Mixed tree plantations Monospecific plantations

pH modeling for maximum dissolved organic matter removal by enhanced coagulation

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Journal of Environmental Sciences 2012年第2期24卷 276-283页

作者： Jiankun Xie Dongsheng Wang John van Leeuwen Yanmei Zhao Linan Xing Christopher W. K. Chow State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China SA Water centre for Water Management and Reuse NBE Universit of South Australia Australia Australian Water Quality centre SA Water 250 Victoria Square Adelaide SA 5000 Australia

Correlations between raw water characteristics and pH after enhanced coagulation to maximize dissolved organic matter（DOM） removal using four typical coagulants（FeCl3,Al2（SO4）3,polyaluminum chloride（PACl） and high performance polyaluminum chloride（HPAC）） without pH control were investigated.These correlations were analyzed on the basis of the raw water quality and the chemical and physical fractionations of DOM of thirteen Chinese source waters over three seasons.It was found that the final pH after enhanced coagulation for each of the four coagulants was in？uenced by the content of removable DOM（i.***.hydrophobic and higher apparent molecular weight（AMW） DOM）,the alkalinity and the initial pH of raw water.A set of feed-forward semi-empirical models relating the final pH after enhanced coagulation for each of the four coagulants with the raw water characteristics were developed and optimized based on correlation analysis.The established models were preliminarily validated for prediction purposes,and it was found that the deviation between the predicted data and actual data was low.This result demonstrated the potential for the application of these models in practical operation of drinking water treatment plants.

关键词： enhanced coagulation modeling DOM fractionation pH control

GCH1 variants contribute to the risk and earlier age-at-onset of Parkinson's disease:a two-cohort case-control study

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Translational Neurodegeneration 2020年第3期9卷 409-420页

作者： Hong-xu Pan Yu-wen Zhao Jun-pu Mei Zheng-huan Fang Yige Wang Xun Zhou Yang-jie Zhou Rui Zhang Kai-lin Zhang Li Jiang Qian Zeng Yan He Zheng Wang Zhen-hua Liu Qian Xu Qi-ying Sun Yang Yang Ya-cen Hu Ya-se Chen Juan Du Li-fang Lei Hai-nan Zhang Chun-yu Wang Xin-xiang Yan Lu Shen Hong Jiang Jie-qiong Tan Jin-chen Li Bei-sha Tang Ji-feng Guo Department of Neurology Xiangya HospitalCentral South UniversityChangsha 410008China national Clinical Research Center for Geriatric Disorders Xiangya HospitalCentral South UniversityChangsha 410008China centre for Medical Genetics and Hunan Key Laboratory of Medical Genetics School of Life SciencesCentral South UniversityChangsha 410008China Department of Geriatrics Xiangya HospitalCentral South UniversityChangsha 410008China Department of Neurology The Third Xiangya HospitalCentral South UniversityChangsha 410013China Department of Neurology The Second Xiangya HospitalCentral South UniversityChangsha 410011China Key Laboratory of Hunan Province in Neurodegenerative Disorders Central South UniversityChangsha 410008China

Background:Common and rare variants of guanosine triphosphate cyclohydrolase 1(GCH1)gene may play important roles in Parkinson's disease(PD).However,there is a lack of comprehensive analysis of GCH1 genotypes,especially in non-coding regions.The aim of this study was to explore the genetic characteristics of GCH1,including rare and common variants in coding and non-coding regions,in a large population of PD patients in Chinese mainland,as well as the phenotypic characteristics of GCH1 variant carriers.Methods:In the first cohort of this case-control study,we performed whole-exome sequencing in 1555 patients with early-onset or familial PD and 2234 healthy controls;then in the second cohort,whole-genome sequencing was performed in sporadic late-onset PD samples(1962 patients),as well as 1279 controls.Variants at target GCH1 regions were extracted,and then genetic and detailed phenotypic data were analyzed using regression models and the sequence kernel association test.We also performed a meta-analysis to correlate deleterious GCH1 variants with age at onset(AAO)in PD patients.Results:For coding variants,we identified a significant burden of GCH1 deleterious variants in early-onset or familial PD cases compared to controls(1.2%VS 0.1%,P<0.0001).In the analysis of possible regulatory variants in GCH1 non-coding regions,rs12323905(P=0.001,odds ratio=1.19,95%CI 1.07-1.32)was significantly associated with PD,and variant sets in untranslated regions and intron regions,GCH1 brain-specific expression quantitative trait loci,and two possible promoter/enhancer(GH14J054857 and GH14J054880)were suggestively associated with PD.Genotype phenotype correlation analysis revealed that the carriers of GCH1 deleterious variants manifested younger AAO(P<0.0001),and had milder motor symptoms,milder fatigue symptoms and more autonomic nervous dysfunctions.Meta-analysis of six studies demonstrated 6.4-year earlier onset in GCH1 deleterious variant carriers(P=0.0009).Conclusions:The results highlight the importance of deleterious variant

关键词： Parkinson's disease Age at onset GCH1 Deleterious variants Non-coding variants

A DFT study of the CO adsorption and oxidation at ZnO surfaces and its implication for CO detection

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Chinese Chemical Letters 2020年第6期31卷 1674-1679页

作者： Zibin Ni Shenyuan Bao Xue-Qing Gong Key Laboratory for Advanced Materials Centre for Computational Chemistry and Research Institute of Industrial CatalysisSchool of Chemistry&Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Recently,ZnO-based gas sensors have been successfully fabricated and widely studied for their excellent sensitivity and selectivity,especially in CO detection.However,detailed explorations of their mechanisms are rather limited.Herein,aiming at clarifying the sensing mechanism,we carried out density functional theory(DFT)calculations to track down the CO adsorption and oxidation on the ZnO(1010)and(1120)surfaces.The calculated results show that the lattice O of ZnO(1010)is more reactive than that of ZnO(1120)for CO oxidation.From the calculated energetics and structures,the main reaction product on both surfaces can be determined to be CO2 rather than carbonate.Moreover,the surface conductivity changes during the adsorption and reaction processes of CO were also studied.For both ZnO(1010)and(1120),the conductivity would increase upon CO adsorption and decrease following CO oxidation,in consistence with the reported experimental results.This work can help understand the origins of ZnO-based sensors’performances and the development of novel gas sensors with higher sensitivity and selectivity.

关键词： Density functional theory ZnO Gas sensor CO oxidation Surface conductivity

A constitutive model incorporating grain refinement strengthening on metallic alloys

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Journal of Materials Science & Technology 2021年第29期88卷 233-239页

作者： Shan Cecilia Cao Xiaochun Zhang Yuan Yuan Pengyau Wang Lei Zhang Na Liu Yi Liu Jian Lu Material Genome Institute Shanghai UniversityShanghai 200444China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Department of Mechanical Engineering City University of Hong KongHong KongChina Department of Computer Science University of CaliforniaBerkeleyCA 94720USA College of Material and Textile Engineering Jiaxing UniversityZhejiang 314001.China School of Mechatronics Engineering and Automation Shanghai UniversityShanghai 200444China CityU-Shenzhen Futian Research Institute Shenzhen 518045China centre for Advanced Structural Materials City University of Hong Kong Shenzhen Research InstituteGreater Bay Joint DivisionShenyang National Laboratory for Materials ScienceShenzhen 518057China

Surface nano-crystallization techniques have been recently developed as one of the most effient ways to optimize materials'structure,and therefore develop the local and global mechanical behavior as to increase strength without compromising ductility.In this work,we present a constitutive model incorporating grain refinement hardening to simulate the nano-crystallization technique,specifically,surface mechanical attrition treatment.The computation is implemented using user-defined VUMAT subroutines.As an example of its application,a geometry model with full coverage of random impacts are employed.The results show that the model has rather precise predictability of grain size evolution during plastic deformation.The readily embedded with a computational code of material dynamics enables this novel model to be a promising tool to study the dynamic evolution of microstructures under plastic deformation.

关键词： Surface grain refinement Constitutive model Full coverage random impact Surface mechanical attrition treatment(SMAT)

Real-Time Detection for Magnetic Island of Neoclassical Tearing Mode in EAST Plasma Control System

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Plasma Science and Technology 2016年第2期18卷 197-201页

作者：梁绍勇肖炳甲张洋王淋芳袁旗平罗正平石同辉提昂 Institute of Plasma Physics Chinese Academy of Sciences Collaborative Innovation centre for Advanced Fusion Energy and Plasma Science University of Science and Technology of China

Accurate detection of a magnetic island in real time is one of the important issues for the tearing mode（TM） and neoclassical tearing mode（NTM） control.This paper presents a real-time detection system for the magnetic island of NTM control in the EAST Plasma Control System（PCS）.Diagnosis is based on magnetic periodic perturbation and electron temperature fluctuation caused by the magnetic island.Therefore,a Mirnov measurement has been selected to calculate the island＇s parameters,such as island width,frequency of island rotation,and toroidal number.The electron cyclotron emission（ECE） system can detect the island position,which is calculated by two fast detection algorithms called correlation analysis and Hilbert transform.For future NTM control,real-time equilibrium reconstruction（rt-EFIT） is needed to locate the rational q-surface where the island is detected.This fast detection system is able to detect an island within 3 ms.It can be integrated into PCS to provide effective parameters of the island for NTM control by using EC resonance heating（ECRH） in the next experiment of EAST.

关键词： real time magnetic island Mirnov ECE phase jump

The hidden risk of microplastic-associated pathogens in aquatic environments

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Eco-Environment & Health 2023年第3期2卷 142-151页

作者： Huan Zhong Mengjie Wu Christian Sonne Su Shiung Lam Raymond W.M.Kwong Yuelu Jiang Xiaoli Zhao Xuemei Sun Xuxiang Zhang Chengjun Li Yuanyuan Li Guangbo Qu Feng Jiang Huahong Shi Rong Ji Hongqiang Ren School of Environment Nanjing UniversityState Key Laboratory of Pollution Control and Resource ReuseNanjing 210023China Department of Bioscience Arctic Research CentreAarhus UniversityRoskildeDenmark Higher Institution centre of Excellence(HICoE) Institute of Tropical Aquaculture and Fisheries(AKUATROP)Universiti Malaysia Terengganu21030 Kuala NerusTerengganuMalaysia Department of Biology York University4700 Keele StreetTorontoON M3J 1P3Canada Tsinghua Shenzhen International Graduate School Shenzhen 518055China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China Yellow Sea Fisheries Research Institute Chinese Academy of Fishery SciencesQingdao 266071China Institute of Environmental Research at Greater Bay Area Key Laboratory for Water Quality and Conservation of the Pearl River DeltaMinistry of EducationGuangzhou UniversityGuangzhou 510006China Key Laboratory of Environment and Health(HUST) Ministry of Education&Ministry of Environmental Protectionand State Key Laboratory of Environmental Health(Incubation)School of Public HealthTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China School of Environmental Science and Engineering Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation TechnologySun Yat-sen UniversityGuangzhou 510275China State Key Laboratory of Estuarine and Coastal Research East China Normal UniversityShanghai 200241China University centre for Research and Development Department of ChemistryChandigarh UniversityGharuanMohaliPunjabIndia

Increasing studies of plastisphere have raised public concern about microplastics(MPs)as vectors for pathogens,especially in aquatic environments.However,the extent to which pathogens affect human health through MPs remains unclear,as controversies persist regarding the distinct pathogen colonization on MPs as well as the transmission routes and infection probability of MP-associated pathogens from water to humans.In this review,we critically discuss whether and how pathogens approach humans via MPs,shedding light on the potential health risks involved.Drawing on cutting-edge multidisciplinary research,we show that some MPs may facilitate the growth and long-range transmission of specific pathogens in aquatic environments,ultimately increasing the risk of infection in humans.We identify MP-and pathogen-rich settings,such as wastewater treatment plants,aquaculture farms,and swimming pools,as possible sites for human exposure to MP-associated pathogens.This review emphasizes the need for further research and targeted interventions to better understand and mitigate the potential health risks associated with MP-mediated pathogen transmission.

关键词： Microplastics Pathogens Colonization Transmission Public health

Improved Cubemap model for 3D navigation in geo-virtual reality

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International Journal of Digital Earth 2015年第11期8卷 877-900页

作者： Qishen Duan Jianhua Gong Wenhang Li Shen Shen Rong Li State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingChina Zhejiang&CAS Application centre for Geoinformatics ZhejiangChina

Due to advances in rendering techniques and hardware capability,stereoscopic 3D(s3D)visualization is becoming increasingly common in daily life.However,this does not change the fact that stereo effects and visual comfort depend greatly on how the related parameters are controlled during the production of the s3D images.In geovirtual reality systems,which are important browsers for Digital Earth,the maintenance of these parameters is deeply related to the navigation process.Therefore,the navigation method in such systems requires special care.This paper presents a new flying method based on a Cubemap structure.The method defines a Vehicle model and modifies the original Cubemap structure by adding a front view camera during the navigation;it allows the users to fly through a virtual geographic environment with automatic speed control,smooth collision resolution,and dynamic adjustment of the s3D-related parameters.A user test was conducted to compare this new method with the original method based on the Cubemap structure.The results show that the new method performs better than the former one for it provides a convenient interaction experience with improved stereoscopic effect,and diminishes visual discomfort.

关键词： virtual reality navigation Digital Earth virtual geographic environment