Search results for "NGS"
showing 10 items of 6306 documents
External pressure and composition effects on the atomic and electronic structure of SnWO4
2015
The atomic and electronic structure of tin tungstates, α-SnWO4, α-Sn1.03W0.99O4 and β-SnWO4 ,w as studied by the W L3-edge X-ray absorption spectroscopy and first-principles linear combination of atomic orbital (LCAO) calculations based on the hybrid exchange-correlation density functional (DFT)/ Hartree–Fock (HF) scheme. It was found that the crystal structure of both α-phases is built up of strongly distorted WO6 octahedra, whereas that of β-SnWO4 is composed of nearly regular WO4 tetrahedra. In addition, there are distorted SnO6 octahedra in both α- and β-phases. The metal–oxygen octahedra distortion is explained by the second-order Jahn–Teller effect. The influence of pressure on the st…
Double-Electron Excitations in L-edges X-ray-Absorption Spectra of W, Ir and Cs Oxide Compounds
1993
Very strong double-electron excitations have been observed for the first time in the W, Ir L 3-edge and Cs L 1,2,3-edges X-ray-absorption spectra of tungsten and iridium oxide thin films and cesium oxide containing glasses. They are expressed as peaks with a width of several electron-volts located at the absorption background above the edge. The positions of these features are in good agreement with atomic calculations in the Z+1 approximation. They can be attributed to the transitions 2p4d → 5d5d for the L 2,3-edges and 2s4d → 6p5d for the L 1-edge with the dipole selection rules for the angular and total angular momentum ΔL=±1, ΔJ=0,±1.
Protonation of the Biliverdin IXα Chromophore in the Red and Far-Red Photoactive States of a Bacteriophytochrome
2019
The tetrapyrrole chromophore biliverdin IXα (BV) in the bacteriophytochrome from Deinococcus radiodurans (DrBphP) is usually assumed to be fully protonated, but this assumption has not been systematically validated by experiments or extensive computations. Here, we use force field molecular dynamics simulations and quantum mechanics/molecular mechanics calculations with density functional theory and XMCQDPT2 methods to investigate the effect of the five most probable protonation forms of BV on structural stability, binding pocket interactions, and absorption spectra in the two photochromic states of DrBphP. While agreement with X-ray structural data and measured UV/vis spectra suggest that …
Ag11(SG)7 : A New Cluster Identified by Mass Spectrometry and Optical Spectroscopy
2014
We report a one-step and high yield synthesis of a red-luminescent silver cluster with the molecular formula, Ag11(SG)7 (SG: glutathionate) via reduction of silver ions by sodium borohydride in the presence of the tripeptide, glutathione (GSH). The as-prepared cluster shows prominent absorption features at 485 and 625 nm in its UV-vis absorption spectrum. Aging of the as-prepared cluster solution led to the disappearance of the 625 nm peak, followed by broadening of the 485 nm peak to give three maxima at ?487, 437, and 393 nm in its absorption spectrum. These peaks remain unchanged even after polyacrylamide gel electrophoresis (PAGE), where a single band was observed confirming high purity…
Fabrication and characterization of vacuum deposited fluorescein thin films
2011
Simple vacuum evaporation technique for deposition of dyes on various solid surfaces has been developed. The method is compatible with conventional solvent-free nanofabrication processing enabling fabrication of nanoscale optoelectronic devices. Thin films of fluorescein were deposited on glass, fluorine-tin-oxide (FTO) coated glass with and without atomically layer deposited (ALD) nanocrystalline 20 nm thick anatase TiO2 coating. Surface topology, absorption and emission spectra of the films depends on their thickness and the material of supporting substrate. On a smooth glass surface the dye initially formes islands before merging into a uniform layer after 5 to 10 monolayers. On FTO cove…
DENN, EIGENTLICH, ÜBERHAUPT - THREE “PRAGMATIC PARTICLES” IN GERMAN
2015
A peculiarity of the German language is the extensive use of “pragmatic particles” in spoken language. These particles are generally called Abtönungspartikel (“modulating particles”) and are used to modulate the speaker’s attitude. They have an elusive meaning which is quite difficult for non-native speakers to discern, and they are a challenge to translate into Italian due to the lack of equivalents. Three particularly interesting particles are “denn”, “eigentlich” and “überhaupt”, which are typical of the speech act of asking questions. After a general introduction to the vast field of conversational particles (showing how differently German grammars treat this topic), the present contrib…
Bordón : revista de pedagogía
2013
INTRODUCTION. In this paper we analyze the evolution in the learning approaches of two groups of first-year university students, one excellent and the other average, from a range of eleven degrees and nine colleges of the Polytechnical University of Valencia. These students were selected as excellent or average based on the marks they obtained on their University Entrance Exams. METHODS. We carried out a longitudinal study using quantitative analysis. The students answered the R-SPQ-2questionnaire (Biggs, Kember & Leung, 2001) that measures their learning approaches in three stages throughout the academic year, at the beginning, midway through and at the end of the year. RESULTS. The resear…
Present status and first results of the final focus beam line at the KEK Accelerator Test Facility
2011
ATF2 is a final-focus test beam line which aims to focus the low emittance beam from the ATF damping ring to a vertical size of about 37 nm and to demonstrate nanometer level beam stability. Several advanced beam diagnostics and feedback tools are used. In December 2008, construction and installation were completed and beam commissioning started, supported by an international team of Asian, European, and U.S. scientists. The present status and first results are described.
New exotic beams from the SPIRAL 1 upgrade
2018
Since 2001, the SPIRAL 1 facility has been one of the pioneering facilities in ISOL techniques for reaccelerating radioactive ion beams: the fragmentation of the heavy ion beams of GANIL on graphite targets and subsequent ionization in the Nanogan ECR ion source has permitted to deliver beams of gaseous elements (He, N, O, F, Ne, Ar, Kr) to numerous experiments. Thanks to the CIME cyclotron, energies up to 20 AMeV could be obtained. In 2014, the facility was stopped to undertake a major upgrade, with the aim to extend the production capabilities of SPIRAL 1 to a number of new elements. This upgrade, which is presently under commissioning, consists in the integration of an ECR booster in the…
Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider
2014
The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in ord…