Search results for "SSBA"

Mössbauer and TEM studies of the perovskite system (1-y)La2/3 $$A$$ 1/3TiO3·yLaFeO3

1994

The microscopic nature of the Mossbauer phase analysis has been found as being particularly valuable in testing assumptions suggested by TEM results regarding the microdomain structure and the population of different lattice sites by iron ions in the perovskite system (1-y)La2/3\(A\)1/3TiO3·yLaFeO3 with 0.04<y < 0.25 (\(A\) is an A-site vacancy). This system was found to contain only Fe3+-phases which are stable under normal conditions, but moderate heating in vacuo causes a partial reduction of ferric ions to ferrous ions.

Mössbauer spectroscopy on the reaction center of Rhodopseudomonas viridis

1992

Proteins called “reaction centers” (RC) can be isolated from many photosynthetic bacteria. They have one non-heme iron in a quinone acceptor region. The RC of Rhodopseudomonas viridis contains an additional tightly bound tetra-heme cytochrome c subunit. The electronic configuration of both cytochrome and the non-heme iron has been studied in the crystallized protein by Mossbauer spectroscopy at different redox potentials, pH-values, and with an addition of o-phenanthroline. At high potentials (Eh=+500mV) all heme irons are in the low spin Fe3+-state, and at low potential (Eh=−150mV) they are low spin Fe2+ with the same Mossbauer parameters for all hemes independent of pH. Redox titrations c…

Mössbauer Spectroscopy on Photosynthetic Bacteria: Investigation of Reaction Centers of Rhodopseudomonas Viridis

1990

Crystals of 57Fe enriched reaction centers have been investigated by Mossbauer spectroscopy. The cytochrome irons are in the low spin ferric state. The non-heme iron of the electron accepting side is partly ferrous high spin and partly ferrous low spin (or ferric high spin). Under the conditions of the experiment sodium ascorbate reduces only one cytochrome iron into the ferrous low spin state. Membrane bound proteins become flexible at higher temperatures than proteins with a hydrophilic surface. They are also less flexible, at least up to temperatures of about 250 K.

A M�ssbauer and ESR study of LiNbO3-Fe2O3 for low Fe2O3 concentrations

1989

Samples of the system LiNbO3-Fe2O3 prepared by water quenching and by the double-roller quenching method in the range up to 24 mol% Fe2O3 were investigated by Mossbauer and ESR spectroscopy. In the water quenched samples up to 11 mol% Fe2O3 only the Fe3+ and the Fe2+ valence states could be detected. The Fe2+ concentration decreased with increasing Fe2O3 content. Above 11 mol% Fe2O3 magnetically split Mossbauer spectra indicated the presence of Fe2O3 clusters. The isomer shift values of Fe3+ as a function of Fe2O3 concentration showed jumps at 6 and 11 mol% Fe2O3, whereas no significant changes could be detected in the quadrupole splitting values. The ESR data already exhibited the existenc…

Dynamics of Metal Centers Monitored by Nuclear Inelastic Scattering

2005

Nuclear inelastic scattering of synchrotron radiation has been used now since 10 years as a tool for vibrational spectroscopy. This method has turned out especially useful in case of large molecules that contain a M\"ossbauer active metal center. Recent applications to iron-sulfur proteins, to iron(II) spin crossover complexes and to tin-DNA complexes are discussed. Special emphasis is given to the combination of nuclear inelastic scattering and density functional calculations.

Voiko etiikkaa opettaa : etiikan opetettavuuden tarkastelua Lawrence Kohlbergin, D. Z. Phillipsin ja Martha C. Nussbaumin ajattelun valossa

2016

VOIKO ETIIKKAA OPETTAA? Etiikan opetettavuuden tarkastelua Lawrence Kohlbergin, D. Z. Phillipsin ja Martha C. Nus- sabumin ajattelun valossa Vesa Nuorva Filosofia Pro gradu –tutkielma Yhteiskuntatieteiden ja filosofian laitos Ohjaaja: Professori Mikko Yrjönsuuri Kevät 2016 129 sivua Tutkimuksen tehtävänä oli selvittää etiikan opetuksen mahdollisuutta ja mielekkyyttä yleissivistä- vässä ja ammatillisessa koulutuksessa Suomessa. Näitä koulutuksia säätelevät lait edellyttävät, että oppilaista tulee eettisesti hyvin käyttäytyviä ja vastuullisia kansalaisia. Tutkimuksen näkökulma ei kuitenkaan ole ollut etiikan opetuksessa pedagogisena prosessina, vaan etiikan opetettavuu…

La persona disabile nel pensiero politico di Martha Nussbaum

2010

.Single-Ion Magnetic Behaviour in an Iron(III) Porphyrin Complex: A Dichotomy Between High Spin and 5/2-3/2 Spin Admixture

2020

International audience; A mononuclear iron(III) porphyrin compound exhibiting unexpectedly slow magnetic relaxation, which is a characteristic of single-ion magnet behaviour, is reported. This behaviour originates from the close proximity (approximate to 550 cm(-1)) of the intermediate-spinS=3/2 excited states to the high-spinS=5/2 ground state. More quantitatively, although the ground state is mostlyS=5/2, a spin-admixture model evidences a sizable contribution (approximate to 15 %) ofS=3/2 to the ground state, which as a consequence experiences large and positive axial anisotropy (D=+19.2 cm(-1)). Frequency-domain EPR spectroscopy allowed them(S)= |+/- 1/2&RightAngleBracket;->|+/- 3/2&Rig…

Thermodynamic and spectroscopic study of the binding of dimethyltin(IV) by citrate at 25°C

2006

Thermodynamic (potentiometric and calorimetric) and spectroscopic ( 1 H NMR, 119 Sn Mossbauer) studies were performed in aqueous solution in order to characterize the interaction of dimethyltin(IV) cation with citrate ligand. Six species {(CH 3 ) 2 Sn(cit) - ; [(CH 3 ) 2 Sn] 2 (cit) 2 2- ; (CH 3 ) 2 Sn(cit)H 0 ; (CH 3 ) 2 Sn(cit)OH 2- ; [(CH 3 ) 2 Sn] 2 (cit)OH 0 ; [(CH 3 ) 2 Sn] 2 (cit)(OH) 2 - } were found. All the species formed in this system are quite stable and formation percentages are fairly high. For example, at pH = 7.5 and C (CH3)2Sn = C cit = 10 mmol l -1 , E% for [(CH 3 ) 2 Sn] 2 (cit)(OH) 2 - and (CH 3 ) 2 Sn(cit)OH 2- species reaches 65%. Overall thermodynamic parameters obta…

Språkbadselevers skriftliga kunskaper i svensk grammatik enligt utvecklingsnivåerna av processbarhetsteorin

2016

Tutkielman tarkoituksena oli tarkastella kuudesluokkalaisten kielikylpyoppilaiden ruotsin kieliopin taitoja Manfred Pienemannin prosessoitavuusteorian valossa. Tärkein tutkimuskysymys oli, mille teorian viidestä tasosta oppilaat sijoittuvat. Tutkimuksen materiaalina oli 12 19 oppilaan kirjoittamaa kirjoitelmaa, eli osa kirjoitelmista oli kirjoitettu ryhmässä. Tutkimus oli kvalitatiivinen ja menetelmänä käytettiin teorialähtöistä sisällönanalyysiä. Tulokset osoittivat, että oppilaat sijoittuivat prosessoitavuusteorian neljännelle ja viidennelle tasolle. Parityöskentelystä johtuen tuloksia voidaan tarkastella ennemmin ryhmä- kuin yksilötasolla. Pienestä aineistosta johtuen tuloksia ei myöskää…