Enhancement of local superconductivity in ferromagnetic FeCrB metallic glass by Ar+ ion irradiation

We have reinforced local superconductivity in ferromagnetic Fe(67)Cr(18)B(15) metallic glasses by ion irradiation. Superconductivity in this medium appears due to the presence of large-scale layered clusters of metallic Fe-Cr phase, 150-230 ? in size, with a ferromagnetic (or superparamagnetic) Fe-rich core and nonmagnetic Cr-rich superconducting shell. Here we show that due to the intensification of concentration phase separation in the Fe-Cr clusters under ion (Ar(+)) irradiation, the volume of the superconducting phase increases from the initial 0.4-0.5% up to 7-8%. After irradiation, the resistivity jump Δρ/ρ in the temperature range T=3.1-3.6 K increases ～14 times, reaching 19%, as compared to 1.36% for the initial sample. In the interval of T=3.1-3.6 K, the rate of resistance change reaches 79% K(-1) for the irradiated sample instead of 3.6% K(-1) for the initial sample. In the same temperature interval, the rate of magnetoresistance change increases from 3% K(-1) for the initial sample up to 70% K(-1) after irradiation.     

A convenient synthetic approach to dioncoquinone B and related compounds

A total synthesis of dioncoquinone B and related compounds, including ancistroquinones B, C and malvon A, is presented. The strategy is based on available reagents and can be used as a preparative synthesis of a number of natural and synthetic biologically active (3-alkyl)-2,7,8-di(tri)methoxy(hydroxy)-1,4-naphthoquinones.     

Photofission induced by linearly polarized photons

The asymmetry coefficients of fragments’ angular distribution (FAD) for fission of ^{234, 236, 238}U and ^{238, 240, 242}Pu isotopes, induced by linearly polarized photons, have been calculated. The optimal energies for observing the polarization parts in this asymmetry are found. Based on the experimental data on FAD for ²³²Th photofission induced by linearly polarized photons with the maximum energy E _γ = 10 MeV (with neglect of the contribution of absorption of electric quadruple photons), it is shown that the theoretical and experimental FAD asymmetry coefficients coincide within standard deviations. Original Russian Text ? S.G. Kadmensky, L.V. Titova, O.S. Khmelevskaya, 2009, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2009, Vol. 73, No. 6, pp. 878–881.     

Synthesis of 1-substituted 2-azaspiro[4.5]deca-6,9-dien-8-ones and 2-azaspiro[4.5]deca-1,6,9-trien-8-ones by condensation of 2,6-dimethylphenol with isobutyraldehyde and nitriles

1-Substituted 3,3,7,9-tetramethyl-2-azaspiro[4.5]deca-6,9-dien-8-ones and 3,3,7,9-tetramethyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones were synthesized by three-component condensation of 2,6-dimethylphenol with isobutyraldehyde and nitriles in concentrated sulfuric acid.     

The Interaction of CdSe/ZnS Quantum Dot with Plasmonic Ag Nanoparticles Deposited on Amorphous Hydrogenated Carbon Thin Films

Optics and Spectroscopy - Local fields of metal nanoparticles can change quantum dots (QDs) absorption and luminescence. In this work, we have investigated the interaction of granulated Ag NPs...     

Synthesis and crystal structure of the coordination polymer of silver with 4,4′-bipyridylethylene [Ag(Bpe)](NO3)·3H2O

The compound [Ag(Bpe)](NO₃)·3H₂O (Bpe = 4,4′-bipyridylethylene, C₁₂H₁₀N₂) is prepared and its crystal structure is determined. The crystals are triclinic: a = 9.073(2) Å, b = 10.074(2) Å, c = 10.391(2) Å, α = 61.18(3)°, β = 72.11(3)°, γ = 68.62(3)°, space group P $\bar 1$ , V = 764.7(3) ų, ρ(calcd) = 1.764 g/cm³, Z = 2. The structure is composed of polymeric cationic chains, [Ag(Bpe)] _∞ ⁺ , NO ₃ ^? counterions, and water molecules. The Ag⁺ ions are bound to the two N atoms of two crystallographically nonequivalent Bpe ligands and form a nearly linear coordination (Ag(1)-N(1), 2.129 Å; Ag(1)-N(2), 2.120(4) Å; N(1)Ag(1)N(2), 169.9(2)°).     

States of water adsorbed on perindopril crystals

The relationship between the structural state of adsorbed water, the crystal structure of the substances, and the solubility of the perindopril salt C₁₉H₃₂N₂O₅ · C₄H₁₁N in water was studied by IR spectroscopy and X-ray diffractometry. The high-frequency shift of the stretching vibrations of adsorbed water and the solubility depend on the crystal structure of the drug substance. A reversible chemical reaction occurred between the adsorbed water and the perindopril salt.     

Radiation-induced plastic deformation and the long-range action effect

In materials subjected to radiation, plastic deformation arises in nanometer-sized regions. This deformation resulting from the formation and evolution of 2D defects causes structuring on a nanometer level. Experimental data are presented for the structure and properties of metallic alloys in which plastic deformation is initiated by ion irradiation. In a narrow range of irradiation parameters, states with a characteristic cluster nanostructure appear, which propagate over a large depth (the long-range action effect).     

Structural polymorphism and solubility of medicinal drugs (Using Perindopril as an Example)

The correlation between the structural polymorphism of perindopril salt C₁₉H₃₂N₂O₅ · C₄H₁₁N and its bioavailability has been investigated. During the crystallization of perindopril salt from an organic solvent, a low-symmetry perindopril polymorph is formed when the most polar solvent is used. It is shown that the dissolution rate in water, which is a measure of the bioavailability of any pharmaceutical product, is higher for the perindopril salt grown from the least polar solvent and that the structure has a monoclinic symmetry.