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Radiative properties of quantum emitters in boron nitride from excited state calculations and Bayesian analysis

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npj Computational Materials 2021年第1期7卷 760-766页

作者： Shiyuan Gao Hsiao-Yi Chen Marco bernardi Department of Applied Physics and Material Science California Institute of TechnologyPasadenaCAUSA Department of Physics California Institute of TechnologyPasadenaCAUSA

Point defects in hexagonal boron nitride(hBN)have attracted growing attention as bright single-photon ***,understanding of their atomic structure and radiative properties remains *** we study the excited states and radiative lifetimes of over 20 native defects and carbon or oxygen impurities in hBN using ab initio density functional theory and GW plus Bethe-Salpeter equation calculations,generating a large data set of their emission energy,polarization and *** find a wide variability across quantum emitters,with exciton energies ranging from 0.3 to 4 eV and radiative lifetimes from ns to ms for different defect *** a Bayesian statistical analysis,we identify various high-likelihood charge-neutral defect emitters,among which the native VNNB defect is predicted to possess emission energy and radiative lifetime in agreement with *** work advances the microscopic understanding of hBN single-photon emitters and introduces a computational framework to characterize and identify quantum emitters in 2D materials.

关键词： quantum excited boron

SENSITIVITY OF DARCY'S LAW TO DISCONTINUITIES

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Chinese Annals of Mathematics,Series B 2003年第2期24卷 205-214页

作者： C.bernardi O.PIRONNEAU Laboratoie Jacques-Louis Lions Universite Paris VI-CNRSFrance.Laboratorie Jacques-Louis LionsUniversite Paris VI-IUFFrance.

The authors investigate the sensitivity of hydrostatic pressure of flows through porous media with respect to the position of the soil layers. Indeed, these induce discontinuities of the porosity which is a piecewise constant coefficient K of the partial differential equation satisfied by the pressure u and it leads to the computation of the derivative of u with respect to changes in position of discontinuity surface of K.The analysis relies on a mixed formulation of the problem. Preliminary numerical simulations are given to illustrate the theory. An application to a simple inverse problem is also given.

关键词： Partial differential equations Flow through porous media Sensitivity Darcy's equation Topological optimization

Coronavirus disease 2019 (COVID-19) and prosthetic heart valve: An additional coagulative challenge

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World Journal of Emergency Medicine 2020年第4期11卷 258-259页

作者： Attilio Allione Jacopo Davide Giamello Sara bernardi Giulia Paglietta Giulia Lucia Massimina Cavalot luca Alessio Dutto Daniela Caruso Andrea Tortore Giuseppe Lauria Department of Emergency Medicine Santa Croce and Carle HospitalCuneoItaly School of Emergency Medicine University of TurinTurinItaly

Dear editor,A new infectious disease outbreak,caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),is now spreading all around the world.[1]One of the most critical understandings of the current pandemic of the coronavirus disease 2019(COVID-19)focuses on an imbalanced coagulation *** on the current evidence,we can divide the COVID-19-related hypercoagulable state into two categories[2]:patients without other pre-existing indications for anticoagulant therapy who develop a state of hypercoagulability linked to SARS-CoV-2 infection especially during the cytokine storm phase,and patients already on anticoagulation in whom we have to reevaluate their drug choices,dosages,and *** the same time,recent literature recommends the use of heparin in severe SARS-CoV-2 infection,both as thromboembolic prophylaxis and as an anticoagulant therapy,in light of possible anti-infl ammatory and antiviral mechanisms and less pharmacological interferences.[3]This indication should be adopted in all patients except for those with prosthetic heart valves,in whom vitamin K antagonists continue to remain the drug of choice.[4]In this subgroup of patients,strict monitoring of PT-INR is required to maintain the therapeutic *** purpose of this article is to underline the need for good quality evidence regarding the management of this high-risk category of the patient population.

关键词： dosage vitamin respiratory

The Rain on Underground Porous Media Part Ⅰ:Analysis of a Richards Model

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Chinese Annals of Mathematics,Series B 2013年第2期34卷 193-212页

作者： Christine bernardi Adel BLOUZA Linda EL ALAOUI Laboratoire Jacques-Louis Lions CNRS & Université Pierre et Marie CurieBC 1874 Place Jussieu75252 Paris Cedex 05France Laboratoire de Mathématiques Raphaёl Salem(UMR 6085 CNRS) Université de RouenAvenue de l'UniversitéBP 1276801 Saint-tienne-du-RouvrayFrance Universit Paris 13 Sorbonne Paris CitLAGACNRS(UMR 7539)F-93430VilletaneuseFrance

The Richards equation models the water flow in a partially saturated underground porous medium under the *** it rains on the surface,boundary conditions of Signorini type must be considered on this part of the *** authors first study this problem which results into a variational inequality and then propose a discretization by an implicit Euler's scheme in time and finite elements in *** convergence of this discretization leads to the well-posedness of the problem.

关键词： Richards equation, Porous media, Euler's implicit scheme, Finite element discretization Parabolic variational inequality

Love wave tomography in Italy from seismic ambient noise

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Earthquake Science 2010年第5期23卷 487-495页

作者： Hongyi Li Fabrizio bernardi Alberto Michelini Key Laboratory of Geo-detection (China University ofGeosciences Beijing) Ministry of Education Beijing 100083 China School of Geophysics andlnformation Technology China University of Geosciences Beijing 100083 China Istituto Nazionale di Geofisica e Vulcanologia Via di Vigna Murata 605 Rome 00143 Italy

We estimate Love wave empirical Green＇s functions from cross-correlations of ambient seismic noise to study the crust and uppermost mantle structure in Italy. Transverse-component ambient noise data from October 2005 through March 2007 recorded at 114 seismic stations from the Istituto Nazionale di Geofisica e Vulcanologia （INGV） national broadband network, the Mediterranean Very Broadband Seismographic Network （MedNet） and the Austrian Central Institute for Meteorology and Geodynamics （ZAMG） yield more than 2 000 Love wave group velocity measurements using the multiple-filter analysis technique. In the short period band （5-20 s）, the cross-correlations show clearly one-sided asymmetric feature due to non-tmiform noise distribution and high local activities, and in the long period band （〉20 s） this feature becomes weak owing to more diffusive noise distribution. Based on these measurements, Love wave group velocity dispersion maps in the 8-34 s period band are constructed, then the SH wave velocity structures from the Love wave dispersions are inverted. The final results obtained from Love wave data are overall in good agreement with those from Rayleigh waves. Both Love and Rayleigh wave inversions all reveal that the Po plain basin is resolved with low velocity at shallow depth, and the Tyrrhenian sea is characterized with higher velocity below 8 km due to its thin oceanic crust.

关键词： ambient noise Love wave tomography crustal structure Italy

Diet in neurogenic bowel management:A viewpoint on spinal cord injury

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World Journal of Gastroenterology 2020年第20期26卷 2479-2497页

作者： Marco bernardi Anna Lucia Fedullo Elisabetta bernardi Diego Munzi Ilaria Peluso Jonathan Myers Florigio Romano Lista Tommaso Sciarra Department of Physiology and Pharmacology"V.Erspamer" Sapienza University of RomeRome 00185Italy Italian Paralympic Committee Rome 00191Italy Federazione Italiana Pallacanestro In Carrozzina(FIPIC) Rome 00188Italy Department of Biosciences Biotechnologies and BiopharmaceuticsUniversity of Bari"Aldo Moro"Bari 70121Italy Joint Veteran Center Scientific DepartmentArmy Medical CenterRome 00184Italy Research Centre for Food and Nutrition Council for Agricultural Research and Economics(CREA-AN)Rome 00178Italy VA Palo Alto Health Care System and Stanford University Cardiology DivisionPalo AltoCA 94025United States Scientific Department Army Medical CenterRome 00184Italy

The aim of this review is to offer dietary advice for individuals with spinal cord injury(SCI)and neurogenic bowel *** this in mind,we consider health conditions that are dependent on the level of lesion including skeletal muscle atrophy,autonomic dysreflexia and neurogenic *** addition,SCI is often associated with a sedentary lifestyle,which increases risk for osteoporosis and diseases associated with chronic low-grade inflammation,including cardiovascular and chronic kidney *** Mediterranean diet,along with exercise and dietary supplements,has been suggested as an anti-inflammatory intervention in individuals with ***,individuals with chronic SCI have a daily intake of whole fruit,vegetables and whole grains lower than the recommended dietary allowance for the general *** studies have reported an increase in neurogenic bowel dysfunction symptoms after high fiber intake;therefore,this finding could explain the low consumption of plant *** consumption of fibre induces dysbiosis,which is associated with bothendotoxemia and *** can be reduced by exercise and diet in individuals with ***,to summarize our viewpoint,we developed a Mediterranean diet-based diet and exercise pyramid to integrate nutritional recommendations and exercise *** guidelines come from previously suggested recommendations for military veterans with disabilities and individuals with SCI,chronic kidney diseases,chronic pain and irritable bowel *** also considered the recent exercise guidelines and position stands for adults with SCI to improve muscle strength,flexibility and cardiorespiratory fitness and to obtain cardiometabolic ***,dietary advice for Paralympic athletes is suggested.

关键词： Neurogenic bowel dysfunction Body composition Mediterranean diet Food–drug interactions Microbiota Paralympic athletes

Ab initio electron-defect interactions using Wannier functions

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npj Computational Materials 2020年第1期6卷 1540-1546页

作者： I-Te Lu Jinsoo Park Jin-Jian Zhou Marco bernardi Department of Applied Physics and Materials Science California Institute of TechnologyPasadenaCalifornia 91125USA

Computing electron–defect(e–d)interactions from first principles has remained impractical due to computational *** we develop an interpolation scheme based on maximally localized Wannier functions(WFs)to efficiently compute e–d interaction matrix *** interpolated matrix elements can accurately reproduce those computed directly without interpolation and the approach can significantly speed up calculations of e–d relaxation times and defect-limited charge *** show example calculations of neutral vacancy defects in silicon and copper,for which we compute the e–d relaxation times on fine uniform and random Brillouin zone grids(and for copper,directly on the Fermi surface),as well as the defect-limited resistivity at low *** interpolation approach opens doors for atomistic calculations of charge carrier dynamics in the presence of defects.

关键词： defect interpolation copper

Sieving of H_2 and D_2 Through End-to-End Nanotubes

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Communications in Theoretical Physics 2014年第10期61卷 541-549页

作者： Devagnik Dasgupta Debra J.Searles Lamberto Rondoni Stefano bernardi Center for Space Human Robotics IITpolitoTorino 10129Italy Department of Mathematical Sciences and Graphene PoliTo Lab Politecnico di TorinoTorino 10126Italy Australian Institute for Bioengineering and Nanotechnology Centre for Theoretical and Computational Molecular Science the University of QueenslandBrisbaneQld 4072Australia School of Chemistry and Molecular Bioscience the University of QueenslandBrisbaneQld 4072Australia Kavli Institute for Theoretical Physics China the Chinese Academy of Sciences INFN Sezione di TorinoVia P.Giuria 1TorinoItaly

We study the quantum molecular sieving of H2 and D2 through two nanotubes placed end-to-end. An analytic treatment, assuming that the particles have classical motion along the axis of the nanotube and are confined in a potential well in the radial direction, is considered. Using this idealistic model, and under certain conditions, it is found that this device can act as a complete sieve, allowing chemically pure deuterium to be isolated from an isotope mixture. We also consider a more realistic model of two carbon nanotubes and carry out molecular dynamics simulations using a Feynman–Hibbs potential to model the quantum effects on the dynamics of H2 and D2. Sieving is also observed in this case, but is caused by a different process.

关键词： molecular sieving quantum sieving molecular dynamics simulation carbon nanotubes

Intermediate polaronic charge transport in organic crystals from a many-body first-principles approach

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npj Computational Materials 2022年第1期8卷 630-637页

作者： Benjamin K.Chang Jin-Jian Zhou Nien-En Lee Marco bernardi Department of Applied Physics and Materials Science California Institute of TechnologyPasadenaCA91125USA

Charge transport in organic molecular crystals (OMCs) is conventionally categorized into two limiting regimes − band transport,characterized by weak electron-phonon (e-ph) interactions,and charge hopping due to localized polarons formed by strong e-ph ***,between these two limiting cases there is a less well understood intermediate regime where polarons are present but transport does not occur via *** we show a many-body first-principles approach that can accurately predict the carrier mobility in this intermediate regime and shed light on its microscopic *** approach combines a finite-temperature cumulant method to describe strong e-ph interactions with Green-Kubo transport *** apply this parameter-free framework to naphthalene crystal,demonstrating electron mobility predictions within a factor of 1.5−2 of experiment between 100 and 300 *** analysis reveals the formation of a broad polaron satellite peak in the electron spectral function and the failure of the Boltzmann equation in the intermediate regime.

关键词： polaron charge limiting