0000000000846612
AUTHOR
Tiit Kärner
showing 4 related works from this author
Elaboration and characterization of organic/inorganic hybrid nanoporous material incorporating Keggin-type Mo-Si polyanions
2007
A novel nanoporous (pore size of 11 nm in average, BET surface area of 30 m2/g, pore volume of 300 mm3/g) hybrid inorganic-organic material was synthesized using the solid-phase interaction at room temperature of plant-originated phenylpropanoid polymer lignin and a Keggin-type heteropolyanion [SiMo12O40]4-. The partly reduction of Mo(VI) to Mo(V) and complexes formation between lignin and polyanion have been established by EPR, FT-IR and Raman spectroscopy. The XRD pattern and FT-IR spectrum of the hybrid material and indicates that [SiMo12O40]4- anion maintains the Keggin structure.
Retrospective dosimetry for Latvian workers at Chernobyl.
2001
Between 1986 and 1991 approximately 6500 Latvian inhabitants were recruited for clean-up work at the Chernobyl nuclear power plant. Their absorbed doses are usually unknown, because less than half of them had their external exposure officially documented. Clinical investigations show a high morbidity rate for these clean-up workers when compared with that of the general population. In order to understand the causes of their diseases and the impact of ionising radiation, electron spin resonance (ESR) has been used to measure the absorbed doses in human tooth enamel. The doses estimated by ESR were between two and three times higher than previously documented and are in accord with the result…
The Optical And Epr Spectra of Fe(2+) and Fe(3+) Ions in the Blood of the Chernobyl Clean-Up Worker
2007
Electron paramagnetic resonance (EPR) and optical absorption studies of blood were provided for the group of Chernobyl’s NPP accident clean-up workers examined in the Center of Occupational and Radiological medicine of P.Stradins Clinical hospital of Medical Academy of Latvia. The EPR spectra for blood have been studied at low temperature. It is shown that in blood the ion Fe3+ of methemaglobin is in low-spin state with g = 2.3 and in the high spin state with g=6. We observed the additional absorption bands 500 nm (shoulder) and 630 nm in absorption spectra of blood of Chernobyl clean-up worker who has erythrocytosis.
Fast-neutron-induced and as-grown structural defects in magnesium aluminate spinel crystals with different stoichiometry
2019
Abstract Several hole-type paramagnetic defects (a hole localized at a regular oxygen ion near charged structural defect/defects) have been revealed in fast-neutron-irradiated MgO⋅2.5Al2O3 single crystals using the EPR method. Three of them (a dominant V1 and small amount of V2 and V22) were recently revealed in a neutron-irradiated stoichiometric MgAl2O4, while a novel V4 center, ascribed to a hole in a form of O− ion nearby a complex of a magnesium vacancy and a positively charged antisite defect (V4 ≡ O–‑VMg‑Al|Mg), was created by fast neutrons only in a nonstoichiometric single crystal. The pulse annealing of the EPR signal of these centers was compared to that of radiation induced opti…