Search results for "SSB"
showing 10 items of 537 documents
Comparative Mössbauer spectroscopic study of iron impurities in ZnSe
2001
Abstract An anomalous spectral doublet attributed to Fe 2+ impurity pairs is observed in Mossbauer absorption spectra of 57 Fe 0.01 Zn 0.99 Se below room temperature. In Mossbauer emission experiments, ZnSe: 57 Co polycrystal and powder sources exhibit below 45 K the nucleogenic Fe 1+ valence state born as an after effect of the electron-capture decay of 57 Co. Above 8 K, the proportion of the nucleogenic Fe 1+ decreases under the effect of the thermally activated Fe 1+ →Fe 2+ relaxation. The activation energy is estimated to 0.004 eV. While nucleogenic Fe 1+ is absent in ZnSe: 57 Co single crystal spectra, increasing proportions are detected in samples with an enhanced specific surface. Th…
Surface versus bulk composition of a phosphate glass
1994
Transmission and conversion electron Mossbauer spectroscopy as well as photoelectron spectroscopy were applied to study alterations of the surface layer of an iron containing industrial phosphate glass as compared with its bulk. In the surface layer, after polishing and exposure to ambient atmosphere, Fe 2+ is partially oxidized to Fe 3+ . This oxidation, however, does not increase the O/P ratio in this layer, because it goes along with a strong leaching of network modifiers. This leaching leads to a net decrease of the O/P ratio because it overcompensates the relative oxygen increase by Fe 2+ oxidation and by uptake of water
Heat-induced charge transfer in cobalt iron cyanide
2006
The heating of Co(2+) ferricyanide above 801C induces an inner charge transfer from Co(2+) towards Fe(III) to form the mixed valence system Co(2+)Co(III) ferri- ferro-cyanide. This charge transfer takes place preserving the material framework and forming a solid solution of the initial and final species. The cell edge of the cubic cell (Fm-3m) of this solid solution follows a regular variation with
Relationship between XPS core binding energies and atomic charge in adducts of SnIV derivatives with pyrazine, and comparison with mössbauer isomer s…
1981
Abstract Adducts Snhal·pyz (hal = Cl, Br, I; pyz = pyrazine), RnSnCl 4−n ·pyz (n = 1, R = Me, Bu n , Oct n , Ph; n = 2, R = Ph) and SnCl 4 ·(pyz) 2 have been investigated by X-ray photoelectron spectroscopy. Binding energy (b.e.) values are discussed in the light of structural characteristics of the adducts as well as of valence state electronegativities of atoms and groups bound to tin. Sn 3d 5 2 b.e.s, corrected for the Madelung potential at the metal atom, linearly correlate with both partial atomic charges on tin, accounting for relaxation upon ionization, and 119 Sn Mossbauer isomer shifts. The results are interpreted in terms of six-coordinated, octahedral type, configurations of the …
Biferrocene Amino Acid, a Ferrocenylogoue of Ferrocene Amino Acid: Synthesis, Cross-Linking, and Redox Chemistry
2010
Access of the novel biferrocene amino acid 7 is provided by two different routes, namely, via desymmetrization of a biferrocene and via palladium-catalyzed cross-coupling of two substituted ferrocenes. The dissymmetric biferrocene 7 is head−head coupled to ureylene-bridged bis(biferrocene) 9 and also head−tail coupled to amide-bridged bis(biferrocene) 14. The monomer 7 and the dimers 9 and 14 are oxidized to mixed-valent cations 7+, 9+, 92+, and 142+. The valencies are trapped in the solid state as shown by Mossbauer and EPR spectroscopy and by X-ray diffraction analysis of [7](I3). Paramagnetic NMR shift studies (7 → 7+) suggest that the hole is localized at the N-substituted ferrocene uni…
Preparation and XAFS studies of organotin(IV) complexes with adenosine and related compounds and calf thymus DNA
2007
Complexes of adenosine and related compounds (adenosine-5’-monophosphate, adenosine-5’-triphosphate and pyridoxal-5-phosphate) with Bu2SnO and/or BuSnCl2 were prepared in the solid state. The compositions of the complexes were determined by standard analytical methods. It was found that the complexes contain the organotin(IV) moiety and the ligand in a ratio of 1:1. The FT-IR spectra demonstrated that Bu2SnO reacts with the D-ribose moiety of the ligands, while Bu2SnCl2 is coordinated to the deprotonated phosphate group. The basic part of the ligands does not participate directly in complex formation. Comparison of the experimental Mossbauer Δ (quadrupole splitting) values with those calcul…
Optical Performance Evaluation of DSSC-integrated Glassblocks for Active Building Façades
2015
The paper outlines the results of a research, carried out at the University of Palermo, aimed at the assessment of the energy performance of a novel glassblock integrated with 3rd generation Dye-Sensitized Solar Cells (DSSC), which, when installed into panels, allows obtaining translucent building envelopes able to provide high thermal and visual comfort levels while producing clean energy. The paper focuses on the optical analyses of four different configurations of DSSC-integrated glassblocks, carried out by using the optical design software Zemax. The values of optical transmittance, the solar factor and the electric power – calculated for each configuration – are discussed.
Skriftliga språkkunskaper i A-svenska hos finska abiturienter på basis av processbarhetsteori
2016
Tämän tutkimuksen tarkoituksena oli tutkia suomenkielisten, ruotsin kielen pitkää oppimäärää opiskelevien abiturienttien kirjallista kielitaitoa lukio-opintojen loppuvaiheessa. Tutkimushenkilöt (n=12) olivat aloittaneet ruotsin kielen opiskelun alakoulun 3.–5. vuosiluokalla ja valmistautuivat tutkimushetkellä ruotsin kielen pitkän oppimäärän ylioppilaskirjoituksiin. Tutkimuksen pohjana käytettiin Pienemannin prosessoitavuusteoriaa (1998). Tutkittavat kieliopilliset rakenteet olivat inversio väitelauseessa, jälkilauseen sanajärjestys, kieltosanan paikka sivulauseessa, epäsuora kysymys sekä adjektiivi attributiivisena ja predikatiivisena lauseenjäsenenä. Tutkimuksen tulokset osoittavat, että …
Ferromagnetic ordering in GdPdCd
2010
Abstract GdPdCd was obtained in pure form via reaction of the elements in a sealed tantalum tube in a high-frequency furnace. The structure was investigated by X-ray diffraction on both powders and single crystals: ZrNiAl type, P 6 2m , a=758.2(1), c=391.78(7) pm, wR2=0.0410 for 358 F2 values and 14 variables. Striking structural motifs of GdPdCd are two types of palladium-centered tricapped trigonal prisms [Pd1Cd3Gd6] and [Pd2Cd6Gd3]. Together the palladium and cadmium atoms build a three-dimensional network in which the gadolinium atoms fill distorted pentagonal channels. Susceptibility measurements reveal Curie–Weiss behaviour with an effective magnetic moment of 8.2(1) μB/Gd. GdPdCd ord…
Corrigendum to “A diferric complex from metal-assisted methanolysis of di-2,6-(2-pyridylcarbonyl)-pyridine: Structural, magnetic and spectroscopic (M…
2010
Corrigendum to ‘‘A diferric complex from metal-assisted methanolysis of di-2,6-(2-pyridylcarbonyl)-pyridine: Structural, magnetic and spectroscopic (Mossbauer, EPR) study” [Polyhedron 28 (2009) 15] Anastasia N. Georgopoulou , Rosa Adam, Yiannis Sanakis , Catherine P. Raptopoulou , Vassilis Psycharis , Rafael Ballesteros , Belen Abarca , Athanassios K. Boudalis a,* a Institute of Materials Science, NCSR ‘‘Demokritos”, 153 10 Aghia Paraskevi Attikis, Greece Departamento de Quimica Organica, Faculdad de Farmacia, Universidad de Valencia, Avda. Vicente Andres Estelles s/n, 46100 Burjassot (Valencia), Spain