Search results for "orbit"
showing 10 items of 1104 documents
Ab initiosimulations on rutile-based titania nanowires
2012
The rod symmetry groups for monoperiodic (1D) nanostructures have been applied for construction of models for bulk-like TiO2 nanowires (NWs) cut from a rutile-based 3D crystal along the chosen [001] and [110] directions of crystallographic axes. In this study, we have considered nanowires described by both the Ti-atom centered rotation axes as well as the hollow site centered axes passing through the interstitial positions between the Ti and O atoms closest to the axes. The most stable [001]-oriented TiO2 NWs with rhombic cross sections are found to display the energetically preferable {110} facets only while the nanowires with quasi-square sections across the [110] axis are formed by the a…
Lactatbildung aus Zuckern und Zuckeralkoholen in Erythrocyten
1965
Erythrocyten konnen Lactat bilden aus Glucose, Fructose, Sorbit, Xylit und Ribit. Mannit wird nicht umgesetzt. Die Kombinationen Xylit + Glucose, Xylit + Fructose und Sorbit + Glucose ergeben additive Lactatbildung. Bei den Kombinationen Xylit + Sorbit, Xylit + Ribit und Glucose + Fructose addiert sich die Lactatbildung nicht. Uber Konsequenzen dieser Befunde fur die parenterale Therapie wird diskutiert.
Use of site symmetry in supercell models of defective crystals: Polarons in CeO2
2017
The authors thank R. Merkle and G. W. Watson for stimulating discussions. E. K. also acknowledges partial financial support from the Russian Science Foundation for the study of charged defects under the project 14-43-00052. A. C. also acknowledges financial support from the University of Latvia Foundation (Arnis Riekstins's "MikroTik" donation). E. K. and D. G. express their gratitude to the High Performance Computer Centre in Stuttgart (HLRS, project DEFTD 12939) for the provided computer facilities whereas R. A. E. thanks the St. Petersburg State University Computer Center for assistance in high-performance calculations.
Local Bonding Influence on the Band Edge and Band Gap Formation in Quaternary Chalcopyrites
2017
Quaternary chalcopyrites have shown to exhibit tunable band gaps with changing anion composition. Inspired by these observations, the underlying structural and electronic considerations are investigated using a combination of experimentally obtained structural data, molecular orbital considerations, and density functional theory. Within the solid solution Cu2ZnGeS4-x Se x , the anion bond alteration parameter changes, showing larger bond lengths for metal-selenium than for metal-sulfur bonds. The changing bonding interaction directly influences the valence and conduction band edges, which result from antibonding Cu-anion and Ge-anion interactions, respectively. The knowledge of the underlyi…
<title>Quantum chemistry studies of the O K-edge x-ray absorption in WO<formula><inf><roman>3</roman></inf></f…
2008
In this work we present an interpretation of experimental O K-edge x-ray absorption near edge structure (XANES) in perovskite-type WO3 and AWO3 compounds (A = H and Na) using three different first principles approaches: (i) fullmultiple- scattering (FMS) formalism (the real-space FEFF code), (ii) hybrid density functional theory (DFT) method with partial incorporation of exact Hartree-Fock exchange using formalism of the linear combination of atomic orbitals (LCAO) as implemented in the CRYSTAL code; (iii) plane-wave DFT method using formalism of the projectoraugmented waves (PAW) as implemented in the VASP code.
An eclipsing millisecond pulsar in the globular cluster Terzan 5
1990
WE HAVE discovered an eclipsing binary millisecond pulsar in the globular cluster Terzan 5. This, the second known eclipsing binary pulsar after PSR1957 + 20, has a pulse period of 11.56 ms and a very short orbital period of 1.8 hours. In contrast to PSR1957 + 20, where the eclipses occupy about 10 per cent of the orbital period1, the eclipse duration in this pulsar is very variable and never less than one-third of the orbital period. The pulsar is in a circular orbit of radius 0.11 light seconds, which implies a minimum companion mass of 0.089 solar masses, about four times the companion mass of PSR1957 + 20. Timing observations suggest an identification of the pulsar with a variable conti…
ChemInform Abstract: A New C-C Bond Formation Model Based on the Quantum Chemical Topology of Electron Density
2014
ELF topological analyses of bonding changes in non-polar, polar and ionic organic reactions involving the participation of CC(X) double bonds make it possible to establish a unified model for C–C bond formation. This model is characterised by a C-to-C coupling of two pseudoradical centers generated at the most significant atoms of the reacting molecules. The global electron density transfer process that takes place along polar and ionic reactions favours the creation of these pseudoradical centers at the most nucleophilic/electrophilic centers of the reacting molecules, decreasing activation energies. The proposed reactivity model based on the topological analysis of the changes in electron…
Satellite-derived land surface temperature: Current status and perspectives
2013
Abstract Land surface temperature (LST) is one of the key parameters in the physics of land surface processes from local through global scales. The importance of LST is being increasingly recognized and there is a strong interest in developing methodologies to measure LST from space. However, retrieving LST is still a challenging task since the LST retrieval problem is ill-posed. This paper reviews the current status of selected remote sensing algorithms for estimating LST from thermal infrared (TIR) data. A brief theoretical background of the subject is presented along with a survey of the algorithms employed for obtaining LST from space-based TIR measurements. The discussion focuses on TI…
A new radiation infrastructure for the Modular Earth Submodel System (MESSy, based on version 2.51)
2016
Abstract. The Modular Earth Submodel System (MESSy) provides an interface to couple submodels to a basemodel via a highly flexible data management facility (Jöckel et al., 2010). In the present paper we present the four new radiation related submodels RAD, AEROPT, CLOUDOPT and ORBIT. The submodel RAD (with shortwave radiation scheme RAD_FUBRAD) simulates the radiative transfer, the submodel AEROPT calculates the aerosol optical properties, the submodel CLOUDOPT calculates the cloud optical properties, and the submodel ORBIT is responsible for Earth orbit calculations. These submodels are coupled via the standard MESSy infrastructure and are largely based on the original radiation scheme of …
The 54 days orbital period of AX J1820.5-1434 unveiled by Swift
2013
The hard X-ray survey that Swift-BAT has been performing since late 2004 has provided a considerable database for a large number of sources whose hard X-ray emission was poorly known. We are exploiting the BAT survey archive to improve the temporal and spectral characterization of the Galactic hard-X-ray sources. In this letter we focus on the study of the high mass X-ray binary AX J1820.5-1434. All the data relevant to AX J1820.5-1434 have been extracted from the BAT survey archive and analyzed using a folding technique to search for periodical modulations. A broad-band spectral analysis was also performed complementing the BAT spectrum with the available Swift-XRT and XMM-Newton pointed o…