Investigation of Sr uptake by birnessite-type sorbents from seawater

Sorption of micro- and microamounts of Sr from seawater has been studied using granulated Na-birnessite. Distribution coefficients of ⁹⁰Sr in the natural seawater are 0.8–1.2?×?10³ ml g^?1, in the model seawater they are 1.6–1.8?×?10³ ml g^?1. Application of Na-birnessite was shown to be prospective in sorption–desorption–regeneration regime. In dynamic sorption conditions, over 150 bed volumes of seawater can be purified till 5% breakthrough occurs at feed rate 10 BV h^?1. Na-birnessite can be used for ⁹⁰Sr radionuclide removal from liquid radioactive wastes containing seawater.

     

Temperature dependence of charge transferred by dislocation in Kcl: Ba crystals

Abstract

The electrical charge assosiated with dislocation motion in KCl:Ba has been studied within the interval from 77 to 292K using on indentation method. The comparison of the potential difference values at 77 and 292K was performed on condition that the impression diagonals were roughly equal. The kinetics of the potential change was studied.     

Imaging interferometric microscopy

We introduce and demonstrate a new microscopy concept: imaging interferometric microscopy (IIM), which is related to holography, synthetic-aperture imaging, and off-axis-dark-field illumination techniques. IIM is a wavelength-division multiplex approach to image formation that combines multiple images covering different spatial-frequency regions to form a composite image with a resolution much greater than that permitted by the same optical system using conventional techniques. This new type of microscopy involves both off-axis coherent illumination and reinjection of appropriate zero-order reference beams. Images demonstrate high resolution, comparable with that of a high-numerical-aperture (NA) objective, while they retain the long working distance, the large depth of field, and the large field of view of a low-NA objective. A Fourier-optics model of IIM is in good agreement with the experiment.     

Self-assembly of programmed building blocks into structurally uniform dendrimers

Selective and independent dimerization of tri- and tetraurea derivatives was used to build up dendritic assemblies which are uniform in size and structure. Dendrimers with the total molecular masses of about 25 000 g/mol were obtained. The existence of uniform assemblies was proved by 1H and 1H DOSY NMR experiments and also by dynamic light scattering.     

Selective and efficient electrocatalytic way to spirobarbituric dihydrofurans

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Silylated iminophosphonates: Novel reactive synthons for the preparation of fluorinated aminophosphonates and aminophosphonic acids

A convenient synthetic approach towards previously unknown N- and N,O-silylated α-iminophosphonates bearing fluoroalkyl groups at the imine C atom was developed. The synthetic potential of the compounds was demonstrated by their easy functionalization and the straightforward preparation of biorelevant aminophosphonates and free aminophosphonic acids with heterocyclic residues in the α-position.