Lead−barium fluoroborate glass ceramics doped with Nd<Superscript>3+</Superscript> or Er<Superscript>3+</Superscript>

Lead?barium fluoroborate glasses in the PbF₂–BaF₂–B₂O₃, PbF₂–BaO–B₂O₃, and PbO_– BaF₂–B₂O₃ systems doped with rare-earth ions (Nd³⁺ or Er³⁺) are synthesized and studied. It is shown that, based on these glasses, it is possible to produce transparent glass ceramics with fluoride crystalline phases, including ceramics with one crystalline phase of the fluorite structure. The spectral and luminescent properties of the doped glasses, glass ceramics, and polycrystalline complex fluorides containing Pb, Ba, and rare ions are studied.     

Structure and properties of solid solutions based on bismuth niobate Bi<Subscript>3</Subscript>NbO<Subscript>7</Subscript>

Solid solutions Bi₃Nb_1–yW_yO_{7 ± δ}, Bi₃Nb_1–yV_yO_{7 ± δ}, Bi₃Nb_1–yFe_yO_{7 ± δ} (y = 0.1–0.5; Δy = 0.1), and Bi_3–xY_xNb_1–yW_yO_{7 ± δ} (x = 0.05, 0.1; y = 0–0.3; Δy = 0.1) have been studied. The homogeneity ranges of the solid solutions and crystal-chemical parameters have been determined by means of X-ray powder diffraction. The electrical conductivity of sintered samples has been studied by impedance spectroscopy. The joint introduction of yttrium and tungsten into the niobium sublattice does not lead to an increase in the conductivity of solid solutions, and the change of the dopant type has no noticeable effect on this conductivity.     

The <Superscript>57</Superscript>Fe hyperfine interactions in the iron-bearing phases in some LL ordinary chondrites

The study of several LL ordinary chondrites such as NWA 6286 LL6, NWA 7857 LL6 and Chelyabinsk LL5 fragments with different lithology was carried out using scanning electron microscopy with energy dispersion spectroscopy, X-ray diffraction and ⁵⁷Fe Mössbauer spectroscopy with a high velocity resolution at 295 K. Small variations in the ⁵⁷Fe hyperfine parameters were revealed for the M1 and M2 sites in olivine, orthopyroxene and clinopyroxene as well as for α-Fe(Ni, Co), α ₂-Fe(Ni, Co) and γ-Fe(Ni, Co) phases, and for troilite in different samples of studied LL ordinary chondrites.     

A new triterpenic alcohol from Fomitopsis pinicola

From a biologically active fraction of extract from the fungus Fomitopsis pinicola, a new lanostane triterpene was isolated, 3alpha-acetyloxylanosta-8,24-diene-21-ol (1), along with two known triterpenic acids, (2) and (3). The structures of the compounds were elucidated based on their spectral properties. [structure: see text]     

Hydrolysis of magnesium hydride in the presence of ammonium salts

The influence of the nature of ammonium salts (NH₄Cl, (NH₄)₂SO₄, (NH₄)HSO₄, [(CH₃)NH₃]Cl) and their concentration in aqueous solutions on the hydrolysis of magnesium hydride has been studied. The highest degree and fastest rate of hydrolysis are observed at an ammonium salt concentration of ～7.5%. The most efficient activator among the ammonium salts under consideration is (NH₄)HSO₄.     

Atomic-absorption spectrometric determination of catalytic components (Pd,Ti, and Cu) in mixtures based on phenol

Procedures for the determination of palladium, titanium, and copper in organic reaction mixtures based on phenol were developed with the use of atomic absorption spectrometry and various sample preparation techniques: quantitative back extraction of the metals with a 2 M HCl solution; autoclave digestion in an acid mixture of HClO₄, HF, and HNO₃; and decomposition in a muffle furnace. The accuracy of analysis was demonstrated by a comparison between the results of the atomic-absorption spectrometric determination of the elements obtained with the use of all of the sample preparation techniques proposed and the standard addition method. The relative standard deviation in the determination of palladium, copper, and titanium was 7–10%.     

Reaction of indoles with ethyl bromopropynoate over Al<Subscript>2</Subscript>O<Subscript>3</Subscript> surface

1H-Indole and 2-methyl-1H-indole reacted with ethyl 3-bromopropynoate over aluminum oxide to give mixtures of the corresponding ethyl 3-(1H-indol-3-yl)propynoates and ethyl 3,3-bis(1H-indol-3-yl)-acrylates, the latter prevailing.     

Electrochemical characteristics, thermal and chemical compatibility in the La0.7Sr0.3CoO3 electrode-γ-BIFEVOX electrolyte system

The electrochemical characteristics and compatibility of components of the electrode-electrolyte system, where the electrolyte is chosen to be γ-BIFEVOX compositions crystallizing in a stable tetragonal phase and the cathode material is chosen to be composite electrodes of composition La_0.7Sr_0.3CoO₃ + Bi₄V_1.7Fe_0.3O_{11 ? δ}, were studied.