Synthesis and structural features of Np(VI) and Pu(VI) isophthalates

New An(VI) isophthalate complexes [PuO₂(C₈H₄O₄)] (I), Cs₂[(NpO₂)₂(C₈H₄O₄)₃]·4H₂O (II), [H₃O]₂[(NpO₂)₂(C₈H₄O₄)₃]·nH₂O (III), and [H₃O][NpO₂(C₈H₄O₄)(C₈H₅O₄)]·2H₂O (IV) with the An(VI): Lig ratios of 1: 1 (I), 1: 1.5 (II, III), and 1: 2 (IV) were synthesized and studied by single crystal X-ray diffraction. In complex I, the coordination polyhedron of the Pu(1) atom is a pentagonal bipyramid whose equatorial plane is formed by the oxygen atoms of four [C₈H₄O₄]^2– anions. The coordination capacity of the ligand in complex I is maximal among compounds I–IV and equal to 5, with each [C₈H₄O₄]^2– anion binding four PuO₂²⁺ cations into electrically neutral layers. In the structures of II and III, the coordination polyhedra of the Np(1) atoms are hexagonal bipyramids whose equatorial planes are formed by the oxygen atoms of three [C₈H₄O₄]^2– anions. Two crystallographically independent [C₈H₄O₄]^2– anions exhibit the coordination capacity equal to 4, each binding two NpO₂²⁺ cations in the chelate fashion. As a result, doubled anionic layers are formed in the crystals of II and III. Outer-sphere cations influence the packing of doubled layers in the crystals: Complex II crystallizes in the monoclinic system, and complex III, in the orthorhombic system. In the structure of IV, the coordination polyhedron of the Np(1) atom is a hexagonal bipyramid whose equatorial plane is formed by the oxygen atoms of two [C₈H₄O₄]^2– anions and one [C₈H₅O₄]^– anion. The crystallographically independent bridging anion [C₈H₄O₄]^2– exhibits the coordination capacity equal to 4 and binds in the chelate fashion two NpO₂²⁺ cations to form chains, and the independent hydrogen isophthalate anion [C₈H₅O₄]^– binds one neptunyl(VI) cation in the chain in the chelate fashion, exhibiting the coordination capacity equal to 2.     

Mixed-Cation Molybdate Complex of Neptunium(V), Li2Na[NpO2(MoO4)2]·4H2O

Radiochemistry - A new mixed-cation complex Li2Na[NpO2(MoO4)2]·4H2O with NpO2+ : MoO42– = 1 : 2 has been synthesized and structurally characterized. The coordination environment of Np(V)...     

Ground-based microwave spectroradiometer for thermal sounding of the troposphere

The laboratory model of a mobile solid-state uncooled microwave spectroradiometer, operating in the frequency range of 50 to 55 GHz is described. It is designed for remote passive monitoring of the tropospheric temperature. The spectroradiometer consists of a heterodyne receiver with a low noise amplifier at input and 8-channel spectrum analyzer. To ensure the internal calibration of the intensity of the received atmospheric radio emission using the built-in unit type modulator-calibrator based on GaAs diodes with the Schottky barrier. The antenna system of the spectroradiometer consists of a teflon enlightened lens and conical corrugated horn. The device is equipped with an automated control system process measurement, calibration, and data pre-processing.     

Sorption of Actinides in Various Oxidation States on TODGA-Containing TVEX from Nitric,Hydrochloric, and Perchloric Acid Media

Radiochemistry - The static capacity (SC) of the AXIONIT MND40T grade solid extractant (TVEX) based on a macroporous styrene-divinylbenzene copolymer and an extractant, tetraoctyldiglycol diamide...     

A small-angle X-ray scattering study of aqueous solutions of uranium(IV) complexes with lacunar heteropolytungstates

The behavior of aqueous and acid solutions of U(IV) complexes with lacunar heteropolyanions was studied by small-angle X-ray scattering. The polytungstate forms in solutions and in crystals are generally similar. The polyanionic complexes in solutions can exhibit ordering with a period of approximately 5.6–7.8 nm. Such species are probably precursors of the crystalline form.     

Automated microwave radiometer for measuring the atmospheric ozone emission line

The work presents the results of upgrading of microwave spectroradiometer for ground-based remote sensing of Earth’s ozone layer improving essentially the noise temperature (up to value less 1500 K). For this, the low-noise high frequency amplifier was set up in front of the receiver and temperature control of the instrument was changed for stable work of the amplifier.     

Rational selection of semi‐finished products made from aluminium and magnesium alloys for welded structures

The results of investigation of the effect of various defects of welded joints on the fatigue resistance of welded joints are presented and used to normalize the defects taking strength characteristics into account.     

Interaction of U(VI), Np(VI), and Pu(VI) with picolinic (2-pyridinecarboxylic) acid: Complexation in aqueous solutions and synthesis, spectra, and thermal properties of complexes [CH6N3][AnO2(C6H4NO2)3] (An = U, Np, Pu)

Complexation of actinides(VI) (U, Np, Pu) with picolinic acid C₆H₅NO₂ (HPic) in solution was studied by spectrophotometry. In particular, data on the Np(VI) complexation were obtained for the first time. The complexes [AnO₂(HPic)]²⁺, [AnO₂(Pic)]⁺, [AnO₂(Pic)₂], and, presumably, [AnO₂(HPic)(Pic)]⁺, and also mixed picolinate-hydroxide complexes can exist in the solution under different conditions. The stability constants of the complexes were estimated. A series of crystalline actinide(VI) picolinate complexes Gu[AnO₂(Pic)₃] (An = Np, Pu; Pic is picolinate ion, Gu is guanidinium ion) were synthesized, and their structure was determined. The spectra and thermal behavior of the complexes are discussed.     

Reaction of Np(V) with U(IV) in solutions with pH > 2

Oxidation of U(IV) with Np(V) in bicarbonate-carbonic acid solutions and the nature and reactivity of actinide(IV) compounds formed in these media were studied spectrophotometrically.     

Maintainability of compressors under compressor station conditions

Methods of ensuring and enhancing maintainability of Ural series of centrifugal compressors developed by Scientific-Production Association Iskra are discussed. New technical solutions to designing of articles are elucidated and problems of equipment standardization and supply of purchased spare parts and with a set of devices are indicated. A series of organizational measures is proposed to significantly augment operational qualities of compressor equipment.