Search Results

You are looking at 1 - 10 of 208 items for :

  • "Mössbauer spectroscopy" x
  • Refine by Access: All Content x
Clear All

Abstract  

Mössbauer spectroscopy is a dynamic field with applications ranging from physics to biology. This paper gives a review of Mössbauer spectroscopy activities carried out by different groups in China. About thirty groups are distributed all over China for both fundamental and practical aspects. In-beam Mössbauer setup was established at HIRAC accelerator in Lanzhou, and the nuclear scattering facility has already been planned at Shanghai Synchrotron Radiation Light Source. In this review, some recent developments and achievements are discussed, as examples: (1) Brownian motion in anisotropic media, (2) applications to archaeology, and (3) molecule-based magnetic materials.

Restricted access

Summary  

This review considers analytical possibilities of Mössbauer spectroscopy in biomedical research. The results of various biomedical applications of Mössbauer spectroscopy were grouped as quantitative and qualitative studies of biological molecules during molecular diseases, studies of the effect of environmental factors on biological molecules, studies of metabolic processes with Mössbauer elements, studies of dynamic properties, studies of pharmaceuticals containing Mössbauer elements. These results demonstrate wide possibilities of Mössbauer spectroscopy in analysis of various biologically important species for obtaining information about the molecular nature of diseases and pathological processes.

Restricted access

Abstract  

The review discusses various analytical chemical applications of the Mössbauer effect. The labelled atoms used are Mössbauer isotopes and the measured parameters for analysis are those of the Mössbauer spectra. High efficiency of the technique is demonstrated by examples in studies of the structure of compounds, polyfunctional with respect to the Mössbauer element, and of the mecahnism of chemical reactions, first of all, low-temperature solid phase reactions. The application of the emission Mössbauer spectroscopy is also discussed for analytical purposes.

Restricted access

Abstract  

Fe/OOCH/2.2HCOOH obtained by solvolytic reaction of FeCl2.4H2O in formic acid was studied by Mössbauer spectroscopy. It displays two quadrupole doublets. Upon air contact it easily transforms to a high-spin octahedral iron/III/ complex, whereas Fe/OOCH/2.2H2O undergoes a very slow oxidation. The formate complex coordinated with pyridine could not be prepared, instead we obtained the anhydrous phase Fe/OOCH/2.

Restricted access

Abstract  

Alkaline solutions of iron compounds synthesized by anodic dissolution of metallic iron in NaOH media have been studied by Mössbauer spectroscopy. The values of the isomer shift on iron in higher oxidation states are presented. The formation of the peroxoderivatives of iron in the solutions were not fixed.

Restricted access

Abstract  

Gamma-ray holdup measurements of a Mossbauer spectroscopy instrument are described and modeled. In the qualitative acquisitions obtained in a low background area of Savannah River National Laboratory, only Am-241 and Np-237 activity were observed. The Am-241 was known to be the instrumental activation source, while the Np-237 is clearly observed as a source of contamination internal to the instrument. The two sources of activity are modeled separately in two acquisition configurations using two separate modeling tools. The results agree well, demonstrating a content of (1980 ± 150) μCi Am-241 and (110 ± 50) μCi of Np-237.

Restricted access

Abstract  

Selected numbers of representative banded iron formations collected from various mines of iron ore supergroups were investigated using ore microscopy and Mössbauer spectroscopy. The ore microscopy results have been corroborated and compared with Mössbauer spectroscopy outcome. Different iron-bearing minerals present in these banded iron-formations have been quantified by 57Fe Mössbauer spectroscopy. The obtained results have been discussed on the basis of degree of martization and goethite-hematite abundance.

Restricted access

Summary  

An analysis of the iron state in commercial pharmaceuticals containing ferric and ferrous iron compounds, which are used for treatment of iron deficiency, was made by Mössbauer spectroscopy. Small variations of the FeOOH cores of injectable iron-dextran complexes were observed. The presence of ferrous impurity in iron-dextran complexes was found. Characterization of the iron state in vitamins and dietary supplements containing ferrous compounds was made. The presence of ferrous and ferric impurities and iron compounds that were in disagreement with compounds announced by the manufacturer was detected by Mössbauer spectroscopy.

Restricted access

Abstract  

Mössbauer spectroscopy is a useful technique for biomedical applications. To increase analytical possibilities and quality of its biomedical applications a new Mössbauer spectrometric system was developed. This system based on a highly stable, sensitive and precision spectrometer SM-2201 with high velocity resolution and a temperature variable liquid nitrogen cryostat with a moving absorber. The first results of Mössbauer spectroscopy with high velocity resolution demonstrated a decrease in the experimental error in the determination of 57Fe hyperfine parameters and, therefore, an increase of accuracy in analysis of small variations of the iron electronic structure, as well as more reliable fitting of complicated spectra.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors: E. Kuzmann, Z. Klencsár, Z. Homonnay, A Vértes, G. Braga, A. De Oliveira, V. Garg, M. Bódogh, I. Kotsis, and A. Nath

Abstract  

57Fe and 151Eu Mössbauer spectroscopy as well as RF susceptibility measurements were applied to study the effects of Pr substitution either into the rare earth or into the Ba site in Eu1–xPrxBa2Cu3O7– and EuBa2–xPrxCu3O7–, respectively. Site mixing of Pr between the rare earth and Ba sites could be excluded by the utilization of 57Fe Mössbauer spectroscopy. It was found that there exists a correlation between the 151Eu isomer shift and the onset temperature of the superconducting transition independent of the location of Pr. RF susceptibility measurements provide an evidence for a difference in the magnetic moment of Pr substituted for the Eu or Ba sites. The obtained results can be explained by hole filling as the dominant effect of Pr substitution.

Restricted access