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MAGUS: machine learning and graph theory assisted universal structure searcher

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National Science Review 2023年第7期10卷 213-233页

作者： Junjie Wang Hao Gao Yu Han Chi Ding Shuning Pan Yong Wang Qiuhan Jia Hui-Tian Wang dingyu Xing Jian Sun National Laboratory of Solid State Microstructures School of Physics and Collaborative Innovation Center of Advanced Microstructures Nanjing University

Crystal structure predictions based on first-principles calculations have gained great success in materials science and solid state physics.However,the remaining challenges still limit their applications in systems with a large number of atoms,especially the complexity of conformational space and the cost of local optimizations for big systems.Here,we introduce a crystal structure prediction method,MAGUS,based on the evolutionary algorithm,which addresses the above challenges with machine learning and graph theory.Techniques used in the program are summarized in detail and benchmark tests are provided.With intensive tests,we demonstrate that on-the-fly machine-learning potentials can be used to significantly reduce the number of expensive first-principles calculations,and the crystal decomposition based on graph theory can efficiently decrease the required configurations in order to find the target structures.We also summarized the representative applications of this method on several research topics,including unexpected compounds in the interior of planets and their exotic states at high pressure and high temperature(superionic,plastic,partially diffusive state,etc.);new functional materials(superhard,high-energy-density,superconducting,photoelectric materials),etc.These successful applications demonstrated that MAGUS code can help to accelerate the discovery of interesting materials and phenomena,as well as the significant value of crystal structure predictions in general.

关键词： crystal structure searching materials design ab-initio calculations density functional theory high-pressure phase transition

Hydration of iodine adsorbed on the Au(111) surface

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Fundamental Research 2022年第4期2卷 546-549页

作者： Yuanqi ding Lei Xie Xinyi Yao chi Zhang Wei Xu Interdisciplinary Materials Research Center Ollge of Materas Science and EngineringTongi UniversiyShanghai 201804hina

The hydration of halogens has been widely researched because of its close relation with the water desalination and biochemical reactions.In this work,by a combination of scanning tunneling microscopy and X-ray photoelectron spectroscopy,we have explored the hydration process of iodine via the Eley-Rideal process on the Au(111)surface.Moreover,the hydration process of iodine with the presence of the NiPc self-assembled network as a template has also been investigated,where the stepwise hydration of iodine at room temperature can be visualized on Au(111).

关键词： Room temperature On-surface ion hydration Eley-Rideal process Scanning tunneling microscopy X-ray photoelectron spectroscopy

Electronic structures and Mott state of epitaxial TaS_(2) monolayers

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Science china(Physics,Mechanics & Astronomy) 2024年第5期67卷 91-97页

作者： Qichao Tian Chi Ding Xiaodong Qiu Qinghao Meng Kaili Wang Fan Yu Yuyang Mu Can Wang Jian Sun Yi Zhang National Laboratory of Solid State Microstructure School of PhysicsNanjing UniversityNanjing 20093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China School of Physics and Electronic Sciences Changsha University of Science and TechnologyChangsha 410114China Hefei National Laboratory Hefei 230088China

Layered material TaS2hosts multiple structural phases and exotic correlated quantum states,including charge density wave(CDW),superconductivity,quantum spin liquid,and Mott insulating state.Here,we synthesized TaS_(2)monolayers in H and T phases using the molecular beam epitaxial(MBE)method and studied their electronic structures via angle-resolved photoemission spectroscopy(ARPES).We found that the H phase TaS_(2)(H-TaS_(2))monolayer is metallic,with an energy band crossing the Fermi level.In contrast,the T phase TaS_(2)(T-TaS_(2))monolayer shows an insulated energy gap at the Fermi level,while the normal calculated band structure implies it should be metallic without any band gap.However,by considering Hubbard interaction potential U,further density functional theory(DFT)calculation suggests that monolayer T-TaS_(2)could be a CDW Mott insulator,and the DFT+U calculation matches well with the ARPES result.More significantly,the temperature-dependent ARPES result indicates that the CDW Mott state in the T-TaS_(2)monolayer is more robust than its bulk counterpart and can persist at room temperature.Our results reveal that the dimensional effect can enhance the CDW Mott state and provide valuable insights for further exploring the exotic properties of monolayer TaS2.

关键词： temperature monolayer state

Hierarchically porous Co@N-doped carbon fiber assembled by MOF-derived hollow polyhedrons enables effective electronic/mass transport:An advanced 1D oxygen reduction catalyst for Zn-air battery

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Journal of Energy Chemistry 2023年第1期76卷 117-126,I0004页

作者： Yifei Zhang Quanfeng He Zihao Chen Yuqing chi Junwei Sun ding Yuan Lixue Zhang Industrial Research Institute of Nonwovens&Technical Textiles College of Textiles&ClothingQingdao UniversityQingdao 266071ShandongChina College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071ShandongChina College of Chemistry and Chemical Engineering Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM)Xiamen UniversityXiamen 361005FujianChina

Developing advanced oxygen reduction reaction(ORR)electrocatalysts with rapid mass/electron transport as well as conducting relevant kinetics investigations is essential for energy technologies,but both still face ongoing challenges.Herein,a facile approach was reported for achieving the highly dispersed Co nanoparticles anchored hierarchically porous N-doped carbon fibers(Co@N-HPCFs),which were assembled by core-shell MOFs-derived hollow polyhedrons.Notably,the unique one-dimensional(1D)carbon fibers with hierarchical porosity can effectively improve the exposure of active sites and facilitate the electron transfer and mass transfer,resulting in the enhanced reaction kinetics.As a result,the ORR performance of the optimal Co@N-HPCF catalysts remarkably outperforms that of commercial Pt/C in alkaline solution,reaching a limited diffusion current density(J)of 5.85 m A cm^(-2)and a half-wave potential(E_(1/2))of 0.831 V.Particularly,the prepared Co@N-HPCF catalysts can be used as an excellent air-cathode for liquid/solid-state Zn-air batteries,exhibiting great potentiality in portable/wearable energy devices.Furthermore,the reaction kinetic during ORR process is deeply explored by finite element simulation,so as to intuitively grasp the kinetic control region,diffusion control region,and mixing control region of the ORR process,and accurately obtain the relevant kinetic parameters.This work offers an effective strategy and a reliable theoretical basis for the engineering of first-class ORR electrocatalysts with fast electronic/mass transport.

关键词： Oxygen reduction catalyst Metal-organic frameworks Carbon nanofiber Hierarchically porous structure Diffusion kinetics Zn-air battery

Fast wireless sensor for anomaly detection based on data stream in an edge-computing-enabled smart greenhouse

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Digital Communications and Networks 2022年第4期8卷 498-507页

作者： Yihong Yang Sheng ding Yuwen Liu Shunmei Meng Xiaoxiao chi Rui Ma Chao Yan School of Computer Science Qufu Normal UniversityRizhao276826China Shandong Provincial University Laboratory for Protected Horticulture Weifang University of Science and TechnologyShouguangWeifang262700China Department of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing210000China General Education Department Shandong First Medical University(Shandong Academy Of Medical Sciences)Taian271000China

Edge-computing-enabled smart greenhouses are a representative application of the Internet of Things(IoT)technology,which can monitor the environmental information in real-time and employ the information to contribute to intelligent decision-making.In the process,anomaly detection for wireless sensor data plays an important role.However,the traditional anomaly detection algorithms originally designed for anomaly detection in static data do not properly consider the inherent characteristics of the data stream produced by wireless sensors such as infiniteness,correlations,and concept drift,which may pose a considerable challenge to anomaly detection based on data stream and lead to low detection accuracy and efficiency.First,the data stream is usually generated quickly,which means that the data stream is infinite and enormous.Hence,any traditional off-line anomaly detection algorithm that attempts to store the whole dataset or to scan the dataset multiple times for anomaly detection will run out of memory space.Second,there exist correlations among different data streams,and traditional algorithms hardly consider these correlations.Third,the underlying data generation process or distribution may change over time.Thus,traditional anomaly detection algorithms with no model update will lose their effects.Considering these issues,a novel method(called DLSHiForest)based on Locality-Sensitive Hashing and the time window technique is proposed to solve these problems while achieving accurate and efficient detection.Comprehensive experiments are executed using a real-world agricultural greenhouse dataset to demonstrate the feasibility of our approach.Experimental results show that our proposal is practical for addressing the challenges of traditional anomaly detection while ensuring accuracy and efficiency.

关键词： Anomaly detection Data stream DLSHiForest Smart greenhouse Edge computing

High-energy-density metal nitrides with armchair chains

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Matter and Radiation at Extremes 2022年第3期7卷 47-53页

作者： Jianan Yuan Kang Xia Chi Ding Xiaomeng Wang Qing Lu Jian Sun National Laboratory of Solid State Microstructures School of Physics and Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093People’s Republic of China Department of Applied Physics College of ScienceNanjing Forestry UniversityNanjing 210037China

Polymeric nitrogen has attracted much attention owing to its possible application as an environmentally safe high-energy-density material.Based on a crystal structure search method accelerated by the use of machine learning and graph theory and on first-principles calculations,we predict a series of metal nitrides with chain-like polynitrogen(P_(21)-AlN_(6),P2_(1)-GaN_(6),P-1-YN_(6),and P_(4)/mnc-TiN_(8)),all of which are estimated to be energetically stable below 40.8 GPa.Phonon calculations and ab initio molecular dynamics simulations at finite temperature suggest that these nitrides are dynamically stable.We find that the nitrogen in these metal nitrides can polymerize into two types of poly-N^(2-)_(4)chains,in which theπelectrons are either extended or localized.Owing to the presence of the polymerized N4 chains,these metal nitrides can store a large amount of chemical energy,which is estimated to range from 4.50 to 2.71 kJ/g.Moreover,these compounds have high detonation pressures and detonation velocities,exceeding those of conventional explosives such as TNT and HMX.

关键词： chains material energy

Effectiveness of entomopathogenic fungal strains against poplar/willow weevil(Cryptorhynchus lapathi L.)larvae

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Journal of Forestry Research 2022年第5期33卷 1691-1702页

作者： Fang Niu Ya Xing Niya Jia Kai ding Dan Xie Huanwen Chen Defu chi Key Laboratory for Sustainable Forest Ecosyst Management of Ministry of Education College of ForestryNortheast Forestry UniversityHarbin 150040HeilongjiangPeople’s Republic of China

The poplar and willow weevil,Crypto rhynchus lapathi L.,a major universally destructive wood-boring insect has become one of the important quarantine pests that is extremely destructive to forestry development and needs to be controlled.Entomopathogenic fungi(EPF) are considered safe and friendly for humans and the environment and play important roles in controlling insect pest populations.In this study,the screening of entomopathogenic fungi for control of C.lapathi is reported through the evaluation of virulence of four fungal Beauveria bassiana(CFCC81428,CFCC83116,CFCC83486,CFCC87297)strains,one B.brongniartii(CFCC83487) strain and one Metarhizium anisopliae(CFCC88953) strain.The virulence of the different strains was appraised by correct mortality rate,cumulative mortality rate,median lethal concentration(LC_(50)) and median lethal time(LT_(50)).B.bassiana strains CFCC81428 and CFCC83116 were the most virulent among the six strains with a mortality up to 100%,and the LT_(50) were 2.7 and 3.1 days.Five conidia concentrations of three strains(CFCC81428,CFCC83116 and CFCC87298) that caused high virulence was screened for dose-relationship.Their effect on controlling C.lapathi larvae were also determined under field condition by brushing conidia suspensions on C.lapathi larvae infested in a poplar trunk.The cumulative rate in the field was lower than those obtained from the laboratory,but the order of the virulence of different strains did not change.Mortality in all three strains occurred at their highest concentration(1.0 × 10^(8) conidia mL^(-1)).Under field conditions,the CFCC81428 strain was the most effective,causing mortalities of 80.3% and 75.2%in two plots in Beipiao and Lindian counties,respectively,followed by CFCC83116(69.1%,66.6%) and CFCC87298(60.7%,59.3%).Based on our results,the B.bassiana strain CFCC81428 has the potential as a biological insecticide to control C.lapathi larvae.

关键词： Entomopathogenic fungi Pathogenicity Biocontrol control Beauveria bassiana Cryptorhynchus lapathi

Kinetics of nitrobenzene degradation coupled to indigenous microorganism dissimilatory iron reduction stimulated by emulsified vegetable oil

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Journal of Environmental Sciences 2017年第4期29卷 206-216页

作者： Jun Dong Linjie ding Zifang chi Jiansen Lei Yan Su Key Laboratory of Groundwater Resources and Environment Ministry of Education Jilin University Changchun 130021 China. Exploration Unit Of North china Geological Exploration Bureau Tianjin 065201 China Shenyang Academy of Environmental Sciences Shenyang 110000 China

Widespread contamination by nitrobenzene（NB） in sediments and groundwater requires better understanding of the biogeochemical removal process of the pollutant. NB degradation, coupled with dissimilatory iron reduction, is one of the most efficient pollutant removal methods. However, research on NB degradation coupled to indigenous microorganism dissimilatory iron reduction stimulated by electron donors is still experimental. A model for remediation in an actual polluted site does not currently exist.Therefore, in this study, the dynamics was derived from the Michaelis–Menten model（when the mass ratio of emulsified vegetable oil and NB reached the critical value 91：1）. The effect of SO4^（2-）, NO3^-, Ca^（2＋）/Mg^（2＋）, and the grain size of aquifer media on the dynamics were studied, and the NB degradation dynamic model was then modified based on the most significant factors. Utilizing the model, the remediation time could be calculated in a contaminated site.

关键词： Nitrobenzene degradation model Iron reduction Groundwater Emulsified vegetable oil Site remediation

Spatiotemporal patterns of the forage-livestock balance in the Xilin Gol steppe,china:implications for sustainably utilizing grassland-ecosystem services

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Journal of Arid Land 2021年第2期13卷 135-151页

作者： QU Yingbo ZHAO Yuanyuan ding Guodong chi Wenfeng GAO Guanglei Key Laboratory of State Forestry Administration on Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China Yanchi Research Station School of Soil and Water ConservationBeijing Forestry UniversityBeijing 100083China College of Resources and Environmental Economics Inner Mongolia University of Finance and EconomicsHohhot 010017China

Understanding the spatiotemporal patterns of the forage-livestock balance is imperative for regionally arranging animal husbandry production while ensuring sustainable grassland-ecosystem service use.The Xilin Gol steppe is an important native grassland resource in Inner Mongolia Autonomous Region,china.This study aimed to elucidate the dynamics of the forage-livestock balance in the Xilin Gol steppe during the period 2000–2015.We evaluated the forage production and corresponding livestock carrying capacity(LCC)in the growing seasons of 2000–2015 using remote sensing data and field surveys.The spatiotemporal patterns of the forage-livestock balance were then assessed at regional,city(including city,county and banner),and village scales using statistical and household survey data.The results showed that both forage production and LCC decreased in the Xilin Gol steppe from east to west.During the period 2000–2015,the regional average forage production and corresponding LCC fluctuated without following a distinct trend,but were consistent with the variations in precipitation.The forage-livestock balance varied with time,space,and scale.At the regional scale,steppes were overgrazed in the early 2000s,but a forage-livestock balance or even grazing potential was achieved in other years.At the city scale,approximately half of the region exhibited a"forage-livestock balance"since 2000.However,about half of the region still experienced overgrazing,which mainly located in the southwest sandy zones.Such changes may have been affected by the variations in grassland quality,forage production,compensation payment,and so on.We suggest a location-specific management scheme for grazing constraints,ecological compensation payment,and industry development to aid in harmonizing animal husbandry and environmental restoration,while promoting sustainable development goals by 2030.

关键词： forage production livestock carrying capacity forage-livestock balance Xilin Gol steppe sustainable development