Authors:K. Lázár, A. Chandwadkar, P. Fejes, J. Čejka, and A. Ramaswamy
Valency changes of iron and tin in framework-substituted microporous and mesoporous molecular sieves (Fe-ETS-10, Fe-ZSM-5, Fe-AlPO-11, Sn-ZSM-12 and Sn-MCM-41) have been studied under reducing and oxidizing conditions by in situ Mössbauer spectroscopy. It is demonstrated that the structure of the host matrices strongly influences the stabilization and the oxidation state of the ions. Debye temperature,
D, data also are estimated, they support the suggested structural assignment of various species.
Soon after the discovery of the Mössbauer effect, studies were performed on spinels containing various transition metal ions (mostly Fe2+). This method proved very useful for investigating the local symmetry at transition metal ions. In spite of the numerous results, the correct interpretation of the complex quadrupole split spectra is still not given for numerous spinel structures. Since spectra of different shapes were measured for FeAl2O4 and FeCr2O4 by different authors, we performed new measurements on these spinels. The results on FeAl2O4 showed that the statistical distribution of another kind of ions in the positions A may influence the electric field gradient at the Fe2+ ions in the tetrahedral interstices. In FeCr2O4 and in the mixed Fe0.5Mg0.5Cr2O4, the electric field gradient exists at the Fe2+ ions at room temperature indicating that the degeneracy of the orbital doublet of the Fe2+ is removed.
Authors:M. I. Oshtrakh, O. B. Milder, V. A. Semionkin, L. I. Malakheeva, and P. G. Prokopenko
Characterization of iron storage proteins in liver and spleen from normal chicken and chicken with lymphoid leukemia in comparison
with human liver ferritin were considered by Mössbauer spectroscopy (preliminary results). Small differences in Mössbauer
hyperfine parameters for both normal and lymphoid leukemia chicken liver and spleen were observed. The value of quadrupole
splitting for human liver ferritin was higher than those for chicken tissues. A decrease of iron content in lymphoid leukemia
chicken tissues was also found, however, the reason of this fact (pathology or feeding) was not clear yet.
Authors:M. Ahmed, A. Demidov, S. Al-Najjar, and M. Al-Amili
Gamma-spectra of stainless-steel and soil samples have been measured to study the potentialities of using spectroscopy of
γ-radiation from the inelastic scattering of reactor fast neutrons for element analysis of various materials. Contents of
iron, chromium, nickel, manganese, silicon and titanium in stainless steel, and those of silicon, iron, aluminium, magnesium,
calcium, sodium, titanium, carbon and oxygen in soil have been determined by comparing the spectra of the samples with those
of specially prepared mixtures of elements. The distinguishing features, advantages, and limitations of this method are discussed.
The complex formation of curium(III) with L2-aminobutyric acid was characterized by time-resolved laser-induced fluorescence
spectroscopy (TRLFS) at trace Cm(III) concentrations (3·10−7 M). The various curium(III) species, MpHqLr, identified are characterized by their individual luminescence spectra and luminescence lifetimes. The following formation
constants were determined log β101 = 5.17±0.07, log β102 = 9.00±0.07, and log β103 = 11.30±0.09 at ionic strength I = 0.5M. Possible structures of the curium aminobutyrate species will be discussed on the basis of the luminescence lifetime
measurements and the magnitude of the formation constants.
Authors:T. Ossaka, K. Kakegawa, T. Oi, and M. Mukaida
Determination of major elements in natural solid samples by X-ray fluorescence spectroscopy (XRF) with a fusion disc technique is described. Data obtained by the present XRF analytical system were found to have satisfactorily high reliability. Five rock samples and a volcanic ash sample with varying ages ranging from the present to 180 000 years, derived by the current and past volcanic activities in the Unzen area, Nagasaki, Japan were analyzed for their major elements' compositions using the above mentioned system. The chemical composition of the magma under this area has changed very little at least over the last 180 000 years.
Authors:C. Castaneda, R. Gearhart, B. Sanii, P. Englert, D. Drake, and R. Reedy
Planetary gamma-ray spectroscopy can be used to chemically analyze the top soil from planets in future planetary missions. The production from inelastic neutron interaction plays an effective role in the determination on the C and H at the surface. The gamma-ray production cross section from the strongest lines excited in the neutron bombardment of Fe have been measured by the use of a time analyzed quasi-mono-energetic neutron beam and a high purity germanium detector. The results from En=6.5, 32, 43, and 65 MeV are presented.
Authors:Erzsébet Háznagy-Radnai, Klára Pintye-Hódi, Szilvia Czigle, Tamás Martinek, Gábor Janicsák, Imre Máthé, and István Erős
We have isolated five iridoids (harpagide, acetylharpagide, harpagoside, ajugoside, and aucubin) from
L. by a combination of chromatographic methods-NP-TLC, RP-HPLC, and TLC-densitometry. The isolated iridoids were identified on the basis of their physical and spectroscopic properties. Basic information about their structures was obtained from their NMR spectra. X-ray fluorescence spectroscopy can be used for direct determination of inorganic elements in the leaves, stems, and inflorescences of
L. We identified K, Ca, Mo, Fe, Co, Ir, Ga, Tl, and S.
Authors:Giorgos Andreou, Maria Efstathiou, and Ioannis Pashalidis
A relatively rapid, economic and robust procedure is described for the radiometric analysis of uranium in phosphate rock and
phosphogypsum. The analysis is performed by alpha spectroscopy after pre-concentration and separation of uranium by liquid-extraction
using tributyl-phosphate (30% TBP in dodecan) and finally its electrodeposition on stainless steel discs. The method has been
successfully applied to 0.1 g samples of phosphate rock and phosphogypsum resulting in high-quality spectra for measurement
times ≥15 h. The main advantage of the procedure is the use of tracer solution (232U) that allows reliable measurements and evaluation of the separation procedure. The separation efficiency of the proposed
method has been estimated to be (75 ± 20)%.
A 30 Hz YAG laser pumped, narrow-line, optical parametric oscillator (OPO) has been used to investigate the chemical states
of selected compounds in aqueous solution. The OPO system has the advantage that it can scan wavelengths over large ranges
without significant loss of output power. The visible spectra of rare earth complexes in dilute aqueous solutions (as chemical
analogs for the actinides) have been studied and preliminary qualitative results for erbium acetate complexes at the 100 micromolar
level are in good agreement with literature data. Quantitative measurements of the protonation constant for phenol red at
the 100 nanomolar level were measured. The particular implementation of the OPO system used in this work introduced a number
of spectral artifacts due to optical signal overlap with near-infrared water absorption bands. In addition, it was demonstrated
that the concentration limiting factor for photoacoustic spectroscopy is the intrisic absorption of water in the visible region
of the spectrum.