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npj Computational Materials 2020年第1期6卷 350-361页

作者： Daniele Torelli Hadeel Moustafa Karsten W.Jacobsen thomas olsen Computational Atomic-scale Materials Design(CAMD) Department of PhysicsTechnical University of DenmarkDK-2800 Kgs.LyngbyDenmark

We perform a computational screening for two-dimensional(2D)magnetic materials based on experimental bulk compounds present in the Inorganic Crystal Structure Database and Crystallography Open Database.A recently proposed geometric descriptor is used to extract materials that are exfoliable into 2D derivatives and we find 85 ferromagnetic and 61 antiferromagnetic materials for which we obtain magnetic exchange and anisotropy parameters using density functional *** the easy-axis ferromagnetic insulators we calculate the Curie temperature based on a fit to classical Monte Carlo simulations of anisotropic Heisenberg *** find good agreement with the experimentally reported Curie temperatures of known 2D ferromagnets and identify 10 potentially exfoliable 2D ferromagnets that have not been reported *** addition,we find 18 easy-axis antiferromagnetic insulators with several compounds exhibiting very strong exchange coupling and magnetic anisotropy.

关键词： magnetic compounds ferromagnetic

Two-dimensional ferroelectrics from high throughput computational screening

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npj Computational Materials 2023年第1期9卷 1901-1911页

作者： Mads Kruse Urko Petralanda Morten N.Gjerding Karsten W.Jacobsen Kristian S.Thygesen thomas olsen CAMD Department of PhysicsTechnical University of DenmarkDK-2800 Kongens LyngbyDenmark

We report a high throughput computational search for two-dimensional ferroelectric *** starting point is 252 pyroelectric materials from the computational 2D materials database(C2DB)and from these we identify 63 *** particular we find 49 materials with in-plane polarization,8 materials with out-of-plane polarization and 6 materials with coupled in-plane and out-of-plane *** of the known 2D ferroelectrics are recovered by the screening and the far majority of the predicted ferroelectrics are known as bulk van der Waals bonded compounds,which makes them accessible by direct *** roughly 25%of the materials we find a metastable state in the non-polar structure,which may imply a first order transition to the polar ***,we list the magnetic pyroelectrics extracted from the C2DB and focus on the case of VAgP2Se6,which exhibits a three-state switchable polarization vector that is strongly coupled to the magnetic excitation spectrum.

关键词： materials polarization plane

Beyond the RPA and GW methods with adiabatic xc-kernels for accurate ground state and quasiparticle energies

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npj Computational Materials 2019年第1期5卷 202-224页

作者： thomas olsen Christopher E.Patrick Jefferson E.Bates Adrienn Ruzsinszky Kristian S.Thygesen Computational Atomic-Scale Materials Design(CAMD) Department of PhysicsTechnical University of DenmarkKongens LyngbyDenmark Department of Physics University of WarwickCoventry CV47ALUK A.R.Smith Department of Chemistry and Fermentation Sciences Appalachian State UniversityBooneNC 28607USA Department of Physics Temple UniversityPhiladelphiaPA 19122USA Center for Nanostructured Graphene(CNG) Department of PhysicsTechnical University of DenmarkKongens LyngbyDenmark

We review the theory and application of adiabatic exchange–correlation(xc)-kernels for ab initio calculations of ground state energies and quasiparticle excitations within the frameworks of the adiabatic connection fluctuation dissipation theorem and Hedin’s equations,*** different xc-kernels,which are all rooted in the homogeneous electron gas,are introduced but hereafter we focus on the specific class of renormalized adiabatic kernels,in particular the rALDA and *** kernels drastically improve the description of short-range correlations as compared to the random phase approximation(RPA),resulting in significantly better correlation *** effect greatly reduces the reliance on error cancellations,which is essential in RPA,and systematically improves covalent bond energies while preserving the good performance of the RPA for dispersive *** quasiparticle energies,the xc-kernels account for vertex corrections that are missing in the GW *** this context,we show that the short-range correlations mainly correct the absolute band positions while the band gap is less affected in agreement with the known good performance of GW for the *** renormalized xc-kernels offer a rigorous extension of the RPA and GW methods with clear improvements in terms of accuracy at little extra computational cost.

关键词： adiabatic kernels quasi

Shift current photovoltaic efficiency of 2D materials

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npj Computational Materials 2023年第1期9卷 1991-1999页

作者： Mikkel Ohm Sauer Alireza Taghizadeh Urko Petralanda Martin Ovesen Kristian Sommer Thygesen thomas olsen Horia Cornean thomas Garm Pedersen Department of Materials and Production Aalborg University9220 AalborgØstDenmark Department of Mathematical Sciences Aalborg University9220 AalborgØstDenmark Center for Nanostructured Graphene(CNG) 9220 AalborgØstDenmark Computational Atomic-scale Materials Design(CAMD) Department of PhysicsTechnical University of Denmark2800 Kgs.LyngbyDenmark Department of Physics University of the Basque Country(UPV/EHU)Apartado 644Bilbao 48080Spain Center for Nanostructured Graphene(CNG) 2800 Kgs.LyngbyDenmark

Shift current photovoltaic devices are potential candidates for future cheap,sustainable,and efficient electricity *** the present work,we calculate the solar-generated shift current and efficiencies in 326 different 2D materials obtained from the computational database *** apply,as metrics,the efficiencies of monolayer and multilayer *** monolayer efficiencies are generally found to be low,while the multilayer efficiencies of infinite stacks show great ***,the out-of-plane shift current response is considered,and material candidates for efficient out-of-plane shift current devices are *** the screened materials,MXY Janus and MX_(2) transition metal dichalchogenides(TMDs)constitute a prominent subset,with chromium based MXY Janus TMDs holding particular ***,in order to explain the band gap dependence of the PV efficiency,a simple gapped graphene model with a variable band gap is established and related to the calculated efficiencies.

关键词： Shift database multilayer

Insights into carbon dioxide sequestration into coal seams through coupled gas flow-adsorption-deformation modelling

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 26-40页

作者： Hywel thomas Min Chen Geoenvironmental Research Centre Cardiff School of EngineeringCardiff UniversityQueen’s BuildingsThe ParadeNewport RoadCardiffCF243AAUK Key Laboratory of Marine Geology Tongji UniversityShanghai200092China

Injecting carbon dioxide(CO_(2))into coal seams may unlock substantial carbon sequestration *** the coal acts like a carbon filter,it can preferentially absorb significant amounts of CO_(2).To explore this further,desorption of the adsorbed gas due to pressure drop is investigated in this paper,to achieve an improved understanding of the long-term fate of injected CO_(2) during post-injection *** paper presents a dual porosity model coupling gas flow,adsorption and geomechanics for studying coupled processes and effectiveness of CO_(2) sequestration in coals.A new adsorption?desorption model derived based on thermodynamics is incorporated,particularly,the desorption hysteresis is *** reliability of the proposed adsorption-desorption isotherm is examined via validation *** is indicated that occurrence of desorption hysteresis is attributed to the adsorption-induced pore *** injection ceases,the injected gas continues to propagate further from the injection well,while the pressure in the vicinity of the injection well experiences a significant *** the adsorbed gas near the well also decreases,this decrease is less compared to that in pressure because of desorption *** unceasing spread of CO_(2) and drops of pressure and adsorbed gas depend on the degree of desorption hysteresis and heterogeneity of coals,which should be considered when designing CO_(2) sequestration into coal seams.

关键词： CO_(2)geological storage Coal seam Adsorption Desorption hysteresis

CLASSIFICATIONS OF DUPIN HYPERSURFACES IN LIE SPHERE GEOMETRY

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Acta Mathematica Scientia 2024年第1期44卷 1-36页

作者： thomas E.CECIL Department of Mathematics and Computer Science College of the Holy CrossWorcesterMA01610USA

This is a survey of local and global classification results concerning Dupin hypersurfaces in S^(n)(or R^(n))that have been obtained in the context of Lie sphere *** emphasis is on results that relate Dupin hypersurfaces to isoparametric hypersurfaces in *** with these classification results,many important concepts from Lie sphere geometry,such as curvature spheres,Lie curvatures,and Legendre lifts of submanifolds of S^(n)(or R^(n)),are described in *** paper also contains several important constructions of Dupin hypersurfaces with certain special properties.

关键词： Dupin hypersurfaces isoparametric hypersurfaces Lie sphere geometry Lie sphere transformations Lie curvatures

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Influence of water evaporation on elastohydrodynamic lubrication with water-containing polyalkylene glycols

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Friction 2024年第10期12卷 2370-2388页

作者： Stefan HOFMANN thomas LOHNER Karsten STAHL Technical University of Munich School of Engineering and DesignDepartment of Mechanical EngineeringGear Research Center(FZG)Boltzmannstraße 1585748 Garching near MunichGermany

The reduction of frictional power losses in power transmitting gears takes a crucial role in the design of energy-and resource-efficient ***-containing lubricants like glycerol and polyalkylene glycols have shown great potential in achieving friction within the superlubricity regime with coefficients of friction lower than 0.01 under elastohydrodynamic ***,a bio-based production of the base stocks can lead to the development of green ***,one challenge associated with the application of water-containing lubricants to gearboxes is the evaporation of water and its impact on the lubricant *** this study,the influence of water evaporation on elastohydrodynamic friction and film thickness was investigated for three water-containing polyalkylene *** nominal water contents of 20 wt%and 40 wt%and two viscosities were *** results show that the friction increases continuously with higher evaporated water content,while the overall friction level remains low in nearly water-free states.A similar trend is observed for film thickness,where the strong increase in viscosity results in a notable increase in film ***,the sensitivity of friction and film thickness to water evaporation is low for small amounts of evaporated *** allows generous thresholds for permissible variations in water content.

关键词： friction superlubricity aqueous lubrication elastohydrodynamic lubrication(EHL) evaporation polyalkylene glycol

Correlation of In Vivo and In Vitro Methods in Measuring Choroidal Vascularization Volumes Using a Subretinal Injection Induced Choroidal Neovascularization Model

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Chinese Medical Journal 2015年第11期128卷 1516-1522页

作者： Chuang Nie Mao-Nian Zhang Hong-Wei Zhao thomas D olsen Kyle Jackman Lian-Na Hu Wen-Ping Ma Xiao-Fei Chen Juan Wang Ying Zhang Tie-Shah Gao Hiro Uehara Balamurali K Ambat Ling Luo Department of Ophthalmology Chinese PLA General Hospital Beijing 100853 China Department of Ophthalmology The 306th Hospital of PLA Beijing 100101 China Moran Eye Center University of Utah Salt Lake City Utah 84132 USA Department of Ophthalmology The 26th Hospital of PLA Beijing 100094 China

Background： In vivo quantification of choroidal neovascularization （CNV） based on noninvasive optical coherence tomography （OCT） examination and in vitro choroidal flatmount immunohistochemistry stained of CNV currently were used to evaluate the process and severity of age-related macular degeneration （AMD） both in human and animal studies. This study aimed to investigate the correlation between these two methods in murine CNV models induced by subretinal injection. Methods： CNV was developed in 20 C57BL6/j mice by subretinal injection of adeno-associated viral delivery of a short hairpin RNA targeting sFLT-1 （***- 1）, as reported previously. After 4 weeks, CNV was imaged by OCT and fluorescence angiography. The scaling factors for each dimension, x, y, and z （ktm/pixel） were recorded, and the corneal curvature standard was adjusted from human （7.7） to mice （1 .4）. The volume of each OCT image stack was calculated and then normalized by multiplying the number of voxels by the scaling factors for each dimension in Seg3D software （University of Utah Scientific Computing and Imaging Institute, available at http：//***/cibc-software/***）. Eighteen mice were prepared for choroidal flatmounts and stained by CD31. The CNV volumes were calculated using scanning laser confocal microscopy after immunohistochemistry staining. Two mice were stained by Hematoxylin and Eosin for observing the CNV morphology. Results： The CNV volume calculated using OCT was, on average, 2.6 times larger than the volume calculated using the laser confocal microscopy. The correlation statistical analysis showed OCT measuring of CNV correlated significantly with the in vitro method （R： = 0.448, P = 0.001, n = 18）. The correlation coefficient for CNV quantification using OCT and confocal microscopy was 0.693 （n = 18, P = 0.001 ）. Conclusions： There is a fair linear correlation on CNV volumes between in vivo and in vitro methods in CNV models induced by subretinal injectio

关键词： Choroidal Flatmount Choroidal Neovascularization Correlation Spectral-domain Optical Coherence Tomography

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Theory and classification of mass extinction causation

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National Science Review 2024年第1期11卷 16-36页

作者： thomas J.Algeo Jun Shen State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences—Wuhan State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences—Wuhan Department of Geosciences University of Cincinnati

Theory regarding the causation of mass extinctions is in need of systematization, which is the focus of this contribution. Every mass extinction has both an ultimate cause, i.e. the trigger that leads to various climato-environmental changes, and one or more proximate cause(s), i.e. the specific climato-environmental changes that result in elevated biotic mortality. With regard to ultimate causes, strong cases can be made that bolide(i.e. meteor) impacts, large igneous province(LIP) eruptions and bioevolutionary events have each triggered one or more of the Phanerozoic Big Five mass extinctions, and that tectono-oceanic changes have triggered some second-order extinction events. Apart from bolide impacts, other astronomical triggers(*** flares, gamma bursts and supernova explosions) remain entirely in the realm of speculation. With regard to proximate mechanisms, most extinctions are related to either carbon-release or carbon-burial processes, the former being associated with climatic warming, ocean acidification, reduced marine productivity and lower carbonate δ13C values, and the latter with climatic cooling, increased marine productivity and higher carbonate δ13C values. Environmental parameters such as marine redox conditions and terrestrial weathering intensity do not show consistent relationships with carbon-cycle *** this context, mass extinction causation can be usefully classified using a matrix of ultimate and proximate factors. Among the Big Five mass extinctions, the end-Cretaceous biocrisis is an example of a bolide-triggered carbon-release event, the end-Permian and end-Triassic biocrises are examples of LIP-triggered carbon-release events, and the Late Ordovician and Late Devonian biocrises are examples of bioevolution-triggered carbon-burial events. Whereas the bolide-impact and LIP-eruption mechanisms appear to invariably cause carbon release, bioevolutionary triggers can result in variable carbon-cycle changes, e.g. carbon burial durin

关键词： biocrisis ultimate cause proximate cause bolide large igneous province bioevolutionary event

How to enhance agricultural plastic waste management in China?Insights from public participation

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Journal of Integrative Agriculture 2024年第6期23卷 2127-2143页

作者： Aibo Hao thomas Dogot Changbin Yin State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Economics and Rural Development Laboratory TERRA Teaching and Research CentreGembloux Agro-Bio TechUniversity of LiègeGembloux B-5030Belgium Research Center for Agricultural Green Development in China Beijing 100081China

Agricultural plastics play a pivotal role in agricultural ***,due to expensive costs,agricultural plastic waste management(APWM)encounters a vast funding *** one of the crucial stakeholders,the public deserves to make appropriate efforts for ***,identifying whether the public is willing to pay for APWM and clarifying the decisions’driving pathways to explore initiatives for promoting their payment intentions are essential to address the dilemma confronting *** this end,by applying the extended theory of planned behavior(TPB),the study conducted an empirical analysis based on 1,288 residents from four provinces(autonomous regions)of northern *** illustrate that:1)respondents hold generally positive and relatively strong payment willingness towards APWM;2)respondents’attitude(AT),subjective norm(SN),and perceived behavioral control(PBC)are positively correlated with their payment intentions(INT);3)environmental cognition(EC)and environmental emotion(EE)positively moderate the relationships between AT and INT,and between SN and INT,posing significant indirect impacts on *** study’s implications extend to informing government policies,suggesting that multi-entity cooperation,specifically public payment for APWM,can enhance agricultural non-point waste management.

关键词： agricultural plastic waste extended theory of planned behavior public payment environmental cognition environmental emotion

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