Suchergebnisse

The research has been funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP08856540). J. Purans and A.I.Popov acknowledge the ERAF project 1.1.1.1/20/A/057 "Functional Ultrawide Bandgap Gallium Oxide and Zinc Gallate Thin Films and Novel Deposition Technologies". The Institute of Solid State Physics, University of Latvia (Latvia) as the Centre of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD01-2016-2017-Teaming Phase2 under grant agreement No. 739508, project CAMART2. ; Gallium oxide β-Ga2O3 is an important wide-band gap semiconductor. In this study, we have calculated the formation energy and transition levels of oxygen vacancies in β-Ga2O3 crystal using the B3LYP hybrid exchange-correlation functional within the LCAO-DFT approach. The obtained electronic charge redistribution in perfect Ga2O3 shows notable covalency of the Ga-O bonds. The formation of the neutral oxygen vacancy in β-Ga2O3 leads to the presence of deep donor defects with quite low concentration. This is a clear reason why oxygen vacancies can be hardly responsible for n-type conductivity in β-Ga2O3.--//-- Licenced under CC BY 4.0. ; Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP08856540); ERAF project 1.1.1.1/20/A/057 "Functional Ultrawide Bandgap Gallium Oxide and Zinc Gallate Thin Films and Novel Deposition Technologies"; The Institute of Solid State Physics, University of Latvia (Latvia) as the Centre of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD01-2016-2017-Teaming Phase2 under grant agreement No. 739508, project CAMART2.

The surface excitation spectra of the Pd(110) surface is analyzed in the framework of the time-dependent density functional theory. The ab initio electronic structure of this surface is included into the evaluation of the surface response function using a linear response approach. At small momentum transfer the extrapolated energy of the surface plasmon is close to electron-energy-loss-spectroscopy measurements and can be understood considering the bulk Pd dielectric function. However, upon momentum increase the evaluated dispersion of the surface plasmon presents significant discrepancies with the published experimental data. While the experimental surface plasmon dispersion initially presents a strong negative slope, our calculations indicate a weak positive dispersion at all finite momentum transfers where this collective excitation is observed. Interestingly, we do not observe any noticeable effect on the collective surface excitations induced by the large number of surface states in the valence band of Pd(110). These states do not produce any additional mode at energies below the surface plasmon. ; We acknowledge funding from the Project of the Basque Government for consolidated groups of the Basque University, through the Department of Universities (Q-NANOFOT IT1164-19) and Project No. PI2017-30 of the Departamento de Educación, Política Lingüística y Cultura of the Basque Government. U.M., R.E., and J.A. acknowledge support from the Spanish Ministry of Science and Innovation (Grant No. PID2019-107432GB-I00). V.M.S. acknowledges support from the Spanish Ministry of Science and Innovation (Grant No. PID2019–105488GB–I00). ; Peer reviewed

[EN] Unlike homogeneous catalysts that are often designed for particular reactions, zeolites are heterogeneous catalysts that are explored and optimized in a heuristic fashion. We present a methodol. for synthesizing active and selective zeolites by using org. structure-¿directing agents that mimic the transition state (TS) of preestablished reactions to be catalyzed. In these zeolites, the pores and cavities could be generated approaching a mol.-¿recognition pattern. For disproportionation of toluene and isomerization of ethylbenzene into xylenes, the TSs are larger than the reaction products. Zeolite ITQ-¿27 showed high disproportionation activity, and ITQ-¿64 showed high selectivity for the desired para and ortho isomers. For the case of a product and TS of similar size, we synthesized a catalyst, MIT-¿1, for the isomerization of endo-¿dicyclopentane into adamantane. ; This work has been supported by the European Union through the European Research Council (grant ERC-AdG-2014-671093, SynCatMatch) and the Spanish government through the "Severo Ochoa Program" (grant SEV 2012-0267). The Electron Microscopy Service of the Universitat Politecnica de Valencia (UPV) is acknowledged for help with sample characterization. The Red Espanola de Supercomputacion (RES) and Centre de Calcul de la Universitat de Valencia are gratefully acknowledged for computational facilities and technical assistance. E.M.G. acknowledges "La Caixa-Severo Ochoa" International Ph.D. Fellowship (call 2015). We thank I. Millet for technical assistance and V. J. Margarit and A. Cantin for helpful discussions. ; Gallego-Sánchez, EM.; Portilla Ovejero, MT.; Paris-Carrizo, CG.; Leon Escamilla, EA.; Boronat Zaragoza, M.; Moliner Marin, M.; Corma Canós, A. (2017). "Ab initio" synthesis of zeolites for preestablished catalytic reactions. Science. 355(6329):1051-1054. https://doi.org/10.1126/science.aal0121 ; S ; 1051 ; 1054 ; 355 ; 6329 ; Vermeiren, W., & Gilson, J.-P. (2009). Impact of Zeolites on the Petroleum and Petrochemical Industry. Topics ...

Introduction. The German Wings incident in March 2015 has focused attention on the mental wellbeing of pilots. Legislation by the European Union Aviation Safety Agency (2018) requires a psychological assessment with the Maltese Civil Aviation Directorate fully implementing this regulation. ; Research question. Are the norms on the NEO PI-R for the Maltese Ab Initio Pilot Population significantly different to those for Aviation personnel on the Revised NEO Personality Inventory Manual (Costa & McCrae, 2006)? ; Method. A sample of N=55 Maltese Pilots (Male=49; Female=6) were assessed. Scores were compared using the IBM SPSS Version 26 Software. ; Results indicated significant differences across most scores. ; Discussion. This creates a number of issues for the Maltese Aviation psychologists in practice. ; peer-reviewed

Light-matter interaction in plasmonic nanostructures is often treated within the realm of classical optics. However, recent experimental findings show the need to go beyond the classical models to explain and predict the plasmonic response at the nanoscale. A prototypical system is a nanoparticle dimer, extensively studied using both classical and quantum prescriptions. However, only very recently, fully ab initio time-dependent density functional theory (TDDFT) calculations of the optical response of these dimers have been carried out. Here, we review the recent work on the impact of the atomic structure on the optical properties of such systems. We show that TDDFT can be an invaluable tool to simulate the time evolution of plasmonic modes, providing fundamental understanding into the underlying microscopical mechanisms. ; We thankfully acknowledge the financial support by the European Research Council (ERC-2010-AdG Proposal No. 267374 and ERC-2011-AdG Proposal No. 290891), the Spanish Government (grants MAT2011-28581-C02-01, FIS2013-46159-C3-1-P, and MAT2014-53432-C5-5-R), the Basque Country Government (Grupos Consolidados IT-578-13), and COST Action MP1306 (EUSpec)]. PGG, JF, and FJGV acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, through the "María de Maeztu" Programme for Units of Excellence in R&D (MDM-2014-0377). ; Peer reviewed

We have performed this work within the framework of the EUROfusion Consortium receiving funding from the European grant agreement 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Authors thank R. Vila, A.I. Popov, A. Luchshik and R.A. Evarestov for fruitful discussions. To carry out large-scale calculations, we have used the HPC supercomputer at Stuttgart University (Germany) ; We have calculated possible migration trajectories for single-charged interstitial Oi− anion using large-scale hybrid density functional theory within linear combination of atomic orbitals approach to defective α-Al2O3 crystals. The most energetically favorable configuration for charged Oi− anion is formation of pseudo-dumbbell (split interstitial) with a regular Oreg ion. For charged interstitial oxygen migration, the energy barrier turns out to be ∼0.8–1.0 eV. This is considerably smaller than that for a neutral interstitial atoms (1.3 eV), in agreement with experimental data. ; EUROfusion Consortium receiving funding from the European grant agreement 633053; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²

1051 1054 355 6329 ; S Čejka, J., & Wichterlová, B. (2002). ACID-CATALYZED SYNTHESIS OF MONO- AND DIALKYL BENZENES OVER ZEOLITES: ACTIVE SITES, ZEOLITE TOPOLOGY, AND REACTION MECHANISMS. Catalysis Reviews, 44(3), 375-421. doi:10.1081/cr-120005741 J. R. Butler, X. Xiao, R. Hall, U.S. Patent 20,080,319,243 (2008). S. I. Zones, U.S. Patent 4,544,538 (1985). E. Mishani et al.,U.S. Patent 20,110,293,519 (2011). M. K. Rubin, P. Chu, U.S. Patent 4,954,325 (1990). A. S. Fung, S. L. Lawton, W. J. Roth, U.S. Patent 5,362,697 (1994). ; [EN] Unlike homogeneous catalysts that are often designed for particular reactions, zeolites are heterogeneous catalysts that are explored and optimized in a heuristic fashion. We present a methodol. for synthesizing active and selective zeolites by using org. structure-¿directing agents that mimic the transition state (TS) of preestablished reactions to be catalyzed. In these zeolites, the pores and cavities could be generated approaching a mol.-¿recognition pattern. For disproportionation of toluene and isomerization of ethylbenzene into xylenes, the TSs are larger than the reaction products. Zeolite ITQ-¿27 showed high disproportionation activity, and ITQ-¿64 showed high selectivity for the desired para and ortho isomers. For the case of a product and TS of similar size, we synthesized a catalyst, MIT-¿1, for the isomerization of endo-¿dicyclopentane into adamantane. This work has been supported by the European Union through the European Research Council (grant ERC-AdG-2014-671093, SynCatMatch) and the Spanish government through the "Severo Ochoa Program" (grant SEV 2012-0267). The Electron Microscopy Service of the Universitat Politecnica de Valencia (UPV) is acknowledged for help with sample characterization. The Red Espanola de Supercomputacion (RES) and Centre de Calcul de la Universitat de Valencia are gratefully acknowledged for computational facilities and technical assistance. E.M.G. acknowledges "La Caixa-Severo Ochoa" International Ph.D. Fellowship (call 2015). We thank I. ...

Unlike homogeneous catalysts that are often designed for particular reactions, zeolites are heterogeneous catalysts that are explored and optimized in a heuristic fashion. We present a methodology for synthesizing active and selective zeolites by using organic structure-directing agents that mimic the transition state (TS) of preestablished reactions to be catalyzed. In these zeolites, the pores and cavities could be generated approaching a molecular-recognition pattern. For disproportionation of toluene and isomerization of ethylbenzene into xylenes, the TSs are larger than the reaction products. Zeolite ITQ-27 showed high disproportionation activity, and ITQ-64 showed high selectivity for the desired para and ortho isomers. For the case of a product and TS of similar size, we synthesized a catalyst, MIT-1, for the isomerization of endo-dicyclopentane into adamantane. ; This work has been supported by the European Union through the European Research Council (grant ERC-AdG-2014-671093, SynCatMatch) and the Spanish government through the " Severo Ochoa Program " (grant SEV 2012-0267). The Electron Microscopy Service of the Universitat Politècnica de València (UPV) is acknowledged for help with sample characterization. The Red Española de Supercomputación (RES) and Centre de Càlcul de la Universitat de València are gratefully acknowledged for computational facilities and technical assistance. E.M.G. acknowledges " La Caixa – Severo Ochoa " International Ph.D. Fellowship (call 2015). We thank I. Millet for technical assistance and V. J. Margarit and Á. Cantín for helpful discussions.

International audience ; French ab initio military pilots are trained to operate a new generation of aircraft equipped with glass cockpit avionics (Rafale, A400 M). However gaze scanning teachings can still be improved and remain a topic of great interest. Eye tracking devices can record trainee gaze patterns in order to compare them with correct ones. This paper presents experimentation conducted in a controlled simulation environment where trainee behaviors were analyzed with notifications given in real-time. In line with other research in civil aviation, this experimentation shows that student-pilots spend too much time looking at inboard instruments (inside the cockpit). In addition, preliminary results show that different notifications bring modifications of the visual gaze pattern. Finally we discuss future strategies to support a more efficient pilot training thanks to real-time gaze recording and its analysis.

International audience ; French ab initio military pilots are trained to operate a new generation of aircraft equipped with glass cockpit avionics (Rafale, A400 M). However gaze scanning teachings can still be improved and remain a topic of great interest. Eye tracking devices can record trainee gaze patterns in order to compare them with correct ones. This paper presents experimentation conducted in a controlled simulation environment where trainee behaviors were analyzed with notifications given in real-time. In line with other research in civil aviation, this experimentation shows that student-pilots spend too much time looking at inboard instruments (inside the cockpit). In addition, preliminary results show that different notifications bring modifications of the visual gaze pattern. Finally we discuss future strategies to support a more efficient pilot training thanks to real-time gaze recording and its analysis.

35 pages, 8 figures.-- Printed version published on Mar 25, 2002.-- ArXiv pre-print available at: http://arxiv.org/abs/cond-mat/0111138 ; We have developed and implemented a self-consistent density functional method using standard norm-conserving pseudopotentials and a flexible, numerical linear combination of atomic orbitals basis set, which includes multiple-zeta and polarization orbitals. Exchange and correlation are treated with the local spin density or generalized gradient approximations. The basis functions and the electron density are projected on a real-space grid, in order to calculate the Hartree and exchange-correlation potentials and matrix elements, with a number of operations that scales linearly with the size of the system. We use a modified energy functional, whose minimization produces orthogonal wavefunctions and the same energy and density as the Kohn-Sham energy functional, without the need for an explicit orthogonalization. Additionally, using localized Wannier-like electron wavefunctions allows the computation time and memory required to minimize the energy to also scale linearly with the size of the system. Forces and stresses are also calculated efficiently and accurately, thus allowing structural relaxation and molecular dynamics simulations. ; This work was supported by the Fundación Ramón Areces and by Spain's MCyT grant BFM2000-1312. JDG would like to thank the Royal Society for a University Research Fellowship and EPSRC for the provision of computer facilities. DSP acknowledges support from the Basque Government (Programa de Formación de Investigadores). ; Peer reviewed

This research was partly supported by the Kazakhstan Science Project № AP05134367«Synthesis of nanocrystals in track templates of SiO2/Si for sensory, nano- and optoelectronic applications», as well as by Latvian Research Council project lzp-2018/1-0214. Calculations were performed on Super Cluster (LASC) in the Institute of Solid State Physics (ISSP) of the University of Latvia. Authors are indebted to S. Piskunov for stimulating discussions. ; Ab initio calculations of the atomic, electronic and vibrational structure of a pure and Co+2 doped MgF2 crystals were performed and discussed. We demonstrate that Co+2 (3d7) ions substituting for Mg is in the high spin state. In particular, the role of exact non-local exchange is emphasized for a proper reproduction of not only the band gap but also other MgF2 bulk properties. It allows us for reliable estimate of the dopant energy levels position in the band gap, and its comparison with the experimental data. Thus, the present ab initio calculations and experiment data demonstrate that the Co+2 ground state level lies at ≈2 eV above the valence band top. ; Kazakhstan Science Project № AP05134367; Latvian Council of Science project lzp-2018/1-0214; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²

arXiv:1912.09793v1 ; Scanning probe microscopy and spectroscopy, and more recently, single-atom electron spin resonance, have allowed the direct observation of electron dynamics at the atomic limit. The interpretation of data is strongly dependent on model Hamiltonians. However, fitting effective spin Hamiltonians to experimental data lacks the ability to explore a vast number of potential systems of interest. By using plane-wave density functional theory as starting point, we build a multiplet Hamiltonian making use of maximally localized Wannier functions. The Hamiltonian contains spin–orbit and electron–electron interactions needed to obtain the relevant spin dynamics. The resulting reduced Hamiltonian is solved by exact diagonalization. We compare three prototypical cases of 3d transition metals Mn (total spin S = 5/2), Fe (S = 2), and Co (S = 3/2) on MgO with experimental data and find that our calculations can accurately predict the spin orientation and anisotropy of the magnetic adatom. Our method does not rely on experimental input and allows us to explore and predict the fundamental magnetic properties of adatoms on surfaces. ; C.W. acknowledges funding from the Korean Institute of Basic Science under IBS-R027-D1. F.D. acknowledges financial support from Basque Government, grant IT986-16, and Canary Islands program Viera y Clavijo (ref. 2017/0000231). N.L. and J.R.G acknowledge funding from the Ministerio de Ciencia e Innovacion Grant No. RTI2018-097895-B-C44 and FEDER funds. ; Peer reviewed