The Study of Species Diversity of Fungi-Litaliano Allocated with Samples of Cement Composites Containing Limestones of Different Origin and Subjected to Aging at Conditions of the Black Sea Climate

The article presents the results of a study of the decay resistance of cement composites filled with carbonate and silicate rocks. The investigated composites exhibited for one year under conditions of the black sea climate in the open air under a canopy of sea coast and sea water. Species and generic diversity of fungi-Litvinov on the samples, depending on the origin of carbonate rocks and the conditions of aging. By results of researches it is stated that fouling, the number of species in the community, as well as specific species composition to a greater extent depends on the operating conditions of the material, and to a lesser extent on the mineral composition of the filler. The authors give a classification of biological agents- destructors of building materials in their preferred conditions of growth that may be promising for the further development of approaches to deal with them. Installed rational compositions of concrete composites derived from limestones of different origin

Effect of the Order-Disorder Transition on the Electronic Structure and Physical Properties of Layered CuCrS2

The work reports a comprehensive study of the Seebeck coefficient, electrical resistivity and heat capacity of CuCrS2 in a wide temperature range of 100–740 K. It was shown that the value of the Seebeck coefficient is significantly affected by the sample treatment procedure. The order-to-disorder (ODT) phase transition was found to cause a metal-insulator transition (MIT). It was established that the ODT diminishes the Seebeck coefficient at high temperatures (T > 700 K). The DFT calculations of the CuCrS2 electronic structure showed that the localization of copper atoms in octahedral sites makes the band gap vanish due to the MIT. The decrease of CuCrS2 electrical resistivity in the ODT temperature region corresponds to the MIT

Magnetic Properties of Novel Layered Disulfides CuCr0.99Ln0.01S2 (Ln = La…Lu)

The comprehensive study of the lanthanide-doped solid solutions CuCr0.99Ln0.01S2 (Ln = La…Lu) magnetic properties was carried out using static magnetochemistry and differential scanning calorimetry techniques. It was shown that magnetic properties of CuCr0.99Ln0.01S2 are significantly affected by the magnetic properties of the lanthanide ion. The magnetic susceptibility and the effective magnetic moment were found to deviate from the Curie-Weiss law in the temperature 90 K below and 50 K above the order-disorder transition at 695 K. The observed behavior of the temperature dependence of the effective magnetic moment in the order-disorder transition temperature region was described as a result of copper atoms redistribution over different types of the crystallographic sites

Charge Distribution in Layered Lanthanide-Doped CuCr_0.99Ln_0.01S₂ (Ln = Pr–Tb) Thermoelectric Materials

The charge distribution study of metal atoms in CuCr0.99Ln0.01S2 (Ln = Pr–Tb) solid solutions was carried out using X-ray photoelectron spectroscopy (XPS). The analysis of the binding energy of S2p, Cu2p, Cr2p, Ln3d and Ln4d levels allows one to determine the oxidation state of atoms. Copper atoms were found to be monovalent. Chromium and lanthanide atoms were found to be in the trivalent state. Sulfur atoms were found to be in the divalent state. Cationic substitution was found to occur via an isovalent mechanism of Cr3+ to Ln3+. The obtained results were used for the interpretation of the Seebeck coefficient increase for CuCr0.99Ln0.01S2 solid solutions in contrast to the initial CuCrS2 matrix. The largest Seebeck coefficient values of 142 and 148 µV/K were observed at 500 K for CuCr0.99Sm0.01S2 and CuCr0.99Pr0.01S2, respectively. The obtained values are 1.4 times greater in comparison with those for the initial matrix (105 µV/K)

Spin Crossover and Thermochromism in Iron(II) Complexes with 2,6-Bis(1<i>H</i>-imidazol-2-yl)-4-methoxypyridine

New iron(II) complexes with 2,6-bis(1H-imidazol-2-yl)-4-methoxypyridine (L) of the composition [FeL2]An∙mH2O (A = SO42−, n = 1, m = 2 (I); A = ReO4−, n = 2, m = 1 (II); A = Br−, n = 2, m = 2 (III)) have been synthesized and investigated. To determine the coordination ability of the ligand, a single crystal of a copper(II) complex of the composition [CuLCl2] (IV) was obtained and studied by X-ray technique. Compounds I–III were studied using methods of X-ray phase analysis, electron (diffuse reflection spectra), infrared and Mössbauer spectroscopy, static magnetic susceptibility. The study of the µeff(T) dependence showed that the 1A1 ↔ 5T2 spin crossover manifests itself in the compounds. The spin crossover is accompanied by thermochromism: there is a distinct color change orange ↔ red-violet

Synthesis, structure, and magnetic properties of the tetranuclear complex [Cu(tmhd)₂Pb(hfa)₂]₂. Influence of temperature-dependent rotation of CF₃ groups upon EPR spectra

<p>A tetranuclear copper–lead complex based on 2,2,6,6-tetramethylheptane-3,5-dionate and 1,1,1,5,5,5-hexafluoropentane-2,4-dionate ligands was prepared. X-ray diffraction study of the crystal structure of the complex was performed at 296, 240, 120, 100, and 85 K. It was shown that the unit cell parameters do not substantially change, but the intramolecular angles and distances significantly changed. A polycrystalline powder of the complex was characterized by continuous wave X- and Q-band electron paramagnetic resonance (EPR) spectroscopy in the 10-350 K temperature range and by magnetic susceptibility based on the Faraday balance technique in the 77-350 K temperature range. The exchange interaction between the two copper ions was not observed which allowed recording the hyperfine interaction (HFI) with one copper nucleus and super HFI with two nonequivalent outer sphere fluorine nuclei. The outer sphere interaction results in the stabilization of the CF₃ group. Lowering the temperature resulted in the rotation of the CF₃ group and that led to the observation of super HFI from only one fluorine nucleus.</p