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reconstructing seafloor age distributions in lost ocean basins

Geoscience Frontiers 2021年第2期12卷 769-780页

作者： Simon Williams Nicky M.Wright John Cannon Nicolas Flament r.Dietmar Müller Department of Geology Northwest UniversityXi’an710069China State Key Laboratory of Continental Dynamics Northwest UniversityXi’an710069China research School of Earth Sciences The Australian National UniversityACT2601Australia ArC Centre of Excellence for Climate Extremes The Australian National UniversityACT2601Australia EarthByte Group School of GeosciencesUniversity of SydneyAustralia GeoQuEST research Centre School of EarthAtmospheric and Life SciencesUniversity of WollongongNorthfields AvenueNSW2522Australia

reconstructions of past seafloor age make it possible to quantify how plate tectonic forces,surface heat flow,ocean basin volume and global sea level have varied through geological ***,past ocean basins that have now been subducted cannot be uniquely reconstructed,and a significant challenge is how to explore a wide range of possible ***,we investigate possible distributions of seafloor ages from the late Paleozoic to present using published full-plate reconstructions and a new,efficient seafloor age reconstruction workflow,all developed using the open-source software *** test alternative reconstruction models and examine the influence of assumed spreading rates within the Panthalassa Ocean on the reconstructed history of mean seafloor age,oceanic heat flow,and the contribution of ocean basin volume to global sea *** reconstructions suggest variations in mean seafloor age of~15 Myr during the late Paleozoic,similar to the amplitude of variations previously proposed for the Cretaceous to *** reconstructed oceanic age-area distributions are broadly compatible with a scenario in which the long-period fluctuations in global sea level since the late Paleozoic are largely driven by changes in mean seafloor *** suggestions of a constant rate of seafloor production through time can be modelled using our workflow,but require that oceanic plates in the Paleozoic move slower than continents based on current reconstructions of continental motion,which is difficult to reconcile with geodynamic studies.

关键词： Plate reconstructions Sea level Seafloor spreading

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Generalized Jackiw-Teitelboim gravity in presence of Block brane-like models

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Chinese Physics C 2022年第12期46卷 258-270页

作者： I.Andrade D.Bazeia A.S.Lobão Jr. r.Menezes Departamento de Física Universidade Federal da Paraíba58051-970 João PessoaPBBrazil Escola Técnica de Saúde de Cajazeiras Universidade Federal de Campina Grande58900-000 CajazeirasPBBrazil Departamento de Ciências Exatas Universidade Federal da Paraíba58297-000 Rio TintoPBBrazil

We investigate generalized Jackiw-Teitelboim gravity,coupling the dilaton field with two scalar matter *** obtain the equations of motion for the fields and investigate a linear perturbation of the solutions in *** study two specific situations that allow for analytic solutions with topological behavior and check how the dilaton field,the warp factor and the ricci scalar *** particular,we show how the parameters can be used to modify the structure of the ***,the perturbations are,in general,described by intricate coupled differential equations,but in some specific cases,we can construct the corresponding zero modes analytically.

关键词： Dilaton 2D gravity Multifield

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Many-body Interatomic Potentials for Computer Simulation of Physical Processes in Metals and Alloys

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Journal of Materials Science & Technology 1998年第5期14卷 429-433页

作者： Kuznetsov, V.M. rudenskii, G.E. Kadyrov, r.I. Kaminskii, P. Institute of Strength Physics and Material Science Russian Academy of Sciences Siberian Branch Academicheskii av. 2/1 634048 Tomsk Russian Federation

A model of binding forces in metals and alloys, based on the density functional theory and accounted effects of the many-body interactions, was proposed. The developed method can be easily applied for study of metals and alloys by the molecular dynamics simulation. The potentials of interatomic interactions have been found by the proposed method and applied for calculations of equation of state, elastic moduli and phonon dispersion in metals Ni, Al, and alloys NiAl, Ni//3Al. results of the calculations are in good agreement with known experimental data both for pure metals and alloys. (Edited author abstract) 16 refs.

关键词： Nickel

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real Banach * Algebras

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Acta Mathematica Sinica,English Series 2000年第3期16卷 469-486页

作者： Bingren Li Institute of Mathematics,Academy of Mathematics and Systems Sciences,Chinese Academy of Sciences,Beijing 100080,P.r.ChinaDepartment of Mathematics,Chinese University of Hong Kong,Hong Kong,P.r.ChinaPingkwan Tam Department of Mathematics,Chinese University of Hong Kong,Shatin,N.T.,Hong Kong,P.r.China Institute of Mathematics Academy of Mathematics and Systems Sciences Chinese Academy of Sciences Bejing 100080 P. R. China Department of Mathematics Chinese University of Hong Kong Hong Kong P. R. China Department of Mathematics Chinese University of Hong Kong Shatin N. T. Hong Kong P. R. China

In this paper,we study real Banach * algebras *** present the right form of Pták’s inequality[1,4]in the real case,and generalize the results of Vukman in[3]to the general case(algebras with or without an identity).... 详细信息

关键词： real Banach algebra representation radical Enveloping real C-algebra Symmetric real Banach algebra

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Ultimate Strength Prediction of Carbon/Epoxy Tensile Specimens from Acoustic Emission Data

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Journal of Materials Science & Technology 2010年第8期26卷 725-729页

作者： V.Arumugam r.Naren Shankar B.T.N.Sridhar A.Joseph Stanley Department of Aerospace Engineering Madras Institute of TechnologyAnna University

The objective of this paper was to predict the residual strength of post impacted carbon/epoxy composite laminates using an online acoustic emission （AE） monitoring and artificial neural networks （ANN）. The laminates were made from eight-layered carbon （in woven mat form） with epoxy as the binding medium by hand lay-up technique and cured at a pressure of 100 kg/cm2 under room temperature using a 30 ton capacity compression molding machine for 24 h. 21 tensile specimens （ASTM D3039 standard） were cut from the cross ply laminates. 16 specimens were subjected to impact load from three different heights using a Fractovis Plus drop impact tester. Both impacted and non-impacted specimens were subjected to uniaxial tension under the acoustic emission monitoring using a 100 kN FIE servo hydraulic universal testing machine. The dominant AE parameters such as counts, energy, duration, rise time and amplitude are recorded during monitoring. Cumulative counts corresponding to the amplitude ranges obtained during the tensile testing are used to train the network. This network can be used to predict the failure load of a similar specimen subjected to uniaxial tension under acoustic emission monitoring for certain percentage of the average failure load.

关键词： Acoustic emission (AE) Carbon/epoxy laminate Tensile testing Artificial neuralnetworks

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Study of electronic and magnetic properties of MnS layers

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Chinese Physics B 2012年第12期21卷 408-411页

作者： r.Masrour E.K.Hlil M.Hamedoun A.Benyoussef O.Mounkachi Laboratory of Materials ProcessesEnvironment and QualityCady Ayyed UniversityNational School of Applied SciencesSafiMorocco LMPHE(UrAC 12) Faculty of ScienceMohammed V-Agdal UniversityRabatMorocco Institut Neel CNRS et Universite Joseph FourierBP 166F-38042 Grenoble Cedex 9France Institute of Nanomaterials and Nanotechnologies MAScIRRabatMorocco HassanⅡAcademy of Science and Technology RabatMorocco

Self-consistent ab initio calculations, based on the density functional theory （DFT） and using the full potential linear augmented plane wave （FLAPW） method, are performed to investigate both electronic and magnetic properties of the MnS layers. Polarized spin and spin-orbit coupling are included in the calculations within the framework of the antiferromagnetic state between two adjacent Mn layers. Magnetic moments considered to lie along axes are computed. Obtained data from ab initio calculations are used as input data for the high temperature series expansion （HTSE） calculations to compute other magnetic parameters. The zero-field high temperature static susceptibility series of the spin-4.39 nearest-neighbour Heisenberg model on centred face cubic （FCC） and lattices is thoroughly analysed by a power series coherent anomaly method （CAM）. The exchange interactions between the magnetic atoms, the N@el temperature, and the critical exponent associated with the magnetic susceptibility are obtained for the MnS layer.

关键词： MnS layers electronic and magnetic structure magnetic moment N^el temperature,exchange interactions

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Effect of aging treatment on irradiation-induced segregation of high Mn-Cr steel

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 58-61页

作者： D.S.BAE S.P.LEE Y.r.CHO H.TAKAHASHI Department of Advanced Materials Engineering Dong-Eui University Department of Materials Engineering Dong-Eui University Department of Materials Science and Engineering Pusan National University Center for Advanced research of Energy Conversion Materials Hokkaido University

To investigate the effect of aging treatment on irradiation-induced segregation of high Mn-Cr steel, specimens for electron-beam irradiation were prepared from the high Mn-Cr austenitic steel which was solution treated at 1 373 K for 1 h and aging treated at 573 K for 1 000 h, respectively. The electron-beam irradiation was performed at 573 K up to doses of 5.4 dpa in a 1 250 kV HVEM and irradiation-induced segregation analyses were carried out by an EDX in a 200 kV FE-TEM. The results show that void formation is not observed in both solution treated and aging treated ones. The amount of Cr segregation at the grain boundary decreases in the aged one; however, that of Mn is not changed in solution treated one.

关键词： high Mn-Cr steel HVEM electron-beam irradiation irradiation-induced segregation aging

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Pd-gate MOS sensor for detection of methanol and propanol

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Journal of Natural Gas Chemistry 2011年第2期20卷 123-127页

作者： Preeti Pandey J. K. Srivastava V. N. Mishra r. Dwivedi Center for research in Microelectronics Department of Electronics Engineering Institute of Technology Banaras Hindu University

The present paper focused on the detection of methanol and propanol using Pd-gate metal-oxide-semiconductor （MOS） sensor. Surface mor- phology and composition of the gate film were studied by scanning electron microscopy （SEM） and atomic force microscopy （AFM）. The response of the sensor for propanol and methanol was measured as shift in capacitance-voltage （C-V） and conductance-voltage （G-V） curves of the MOS structure. The sensitivity of the sensor towards methanol was found to be greater than that towards propanol. It was 58.2% for methanol and 32% for propanol （at 0.6 V, 1 MHz） in terms of capacitance measurements, while in terms of conductance results the sensitivity was found to be 57.2% for methanol and 38.9% for propanol at 1 kHz. The discontinuities or cracks present in the microstructure of the gate material are believed to be mainly responsible for the high sensitivity of the sensor, going with the decomposition of gas molecules and subsequent hydrogen permeation through Pd.

关键词： MOS structure gas sensor palladium cracks sensitivity

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Comparison of the local pivotal method and systematic sampling for national forest inventories

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Forest Ecosystems 2020年第4期7卷 716-732页

作者： Minna räty Mikko Kuronen Mari Myllymäki Annika Kangas Kai Mäkisara Juha Heikkinen Natural resources Institute Finland(Luke) PO Box 2FI-00791 HelsinkiFinland. Natural resources Institute Finland(Luke) Yliopistokatu 6FI-80100 JoensuuFinland

Background:The local pivotal method(LPM)utilizing auxiliary data in sample selection has recently been proposed as a sampling method for national forest inventories(NFIs).Its performance compared to simple random sampling(SrS)and LPM with geographical coordinates has produced promising results in simulation *** this simulation study we compared all these sampling methods to systematic *** LPM samples were selected solely using the coordinates(LPMxy)or,in addition to that,auxiliary remote sensing-based forest variables(rS variables).We utilized field measurement data(NFI-field)and Multi-Source NFI(MS-NFI)maps as target data,and independent MS-NFI maps as auxiliary *** designs were compared using relative efficiency(rE);a ratio of mean squared errors of the reference sampling design against the studied *** a method in NFI also requires a proven estimator for the ***,three different variance estimators were evaluated against the empirical variance of replications:1)an estimator corresponding to SrS;2)a Grafström-Schelin estimator repurposed for LPM;and 3)a Matérn estimator applied in the Finnish NFI for systematic sampling ***:The LPMxy was nearly comparable with the systematic design for the most target *** rEs of the LPM designs utilizing auxiliary data compared to the systematic design varied between 0.74–1.18,according to the studied target *** SrS estimator for variance was expectedly the most biased and conservative ***,the Grafström-Schelin estimator gave overestimates in the case of *** the rS variables were utilized as auxiliary data,the Grafström-Schelin estimates tended to underestimate the empirical *** systematic sampling the Matérn and Grafström-Schelin estimators performed for practical purposes ***:LPM optimized for a specific variable tended to be more efficient than systematic sampling,but all of the considered LPM designs were

关键词： Auxiliary data Bias Local pivotal method Matérn estimator National forest inventory Sampling efficiency Simple random sampling Spatially balanced sampling Systematic sampling Variance

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On the Limit Cycles of Quadratic Differential Systems

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Acta Mathematica Sinica,English Series 2002年第4期18卷 803-816页

作者： Xiang ZHANG Department of Mathematics, Shanghai Jiaotong University, Shanghai 200030, P. r. China Department of Mathematics Shanghai Jiaotong University Shanghai P. R. China

In this paper we give the necessary and sufficient conditions for all finite critical points of quadratic differential systems to be weak foci, and solve an open problem proposed by Yanqian Ye.

关键词： Quadratic differential system Limit cycle Ergodicity.

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