Structural and transport properties of neodymium tungstates prepared via mechanochemical activation

Nd_5.5WO_11.25-δ, (Nd_5/6La_1/6)_5.5WO_11.25-δ and Nd_5.5W_0.5Mo_0.5O_11.25-δ mixed oxides have been prepared using mechanochemical activation (MA) of Nd₂O₃-WO₃, Nd₂O₃-La₂O₃-WO₃, Nd₂O₃-MoO₃-WO₃ mixtures in a high-power planetary ball mill. Genesis of these tungstates structural properties was studied by XRD, SEM, TEM with EDX analysis, ¹H NMR, IR and Raman spectroscopy. X-ray diffraction has revealed that MA results in formation of a pure fluorite structure already after milling. High-density ceramic pellets have been obtained after sintering at 1350?°C. Transport properties of Nd_5.5WO_11.25-δ mixed oxide were improved by the partial substitution of Nd with La in (Nd_5/6La_1/6)_5.5WO_11.25-δ and W with Mo in Nd_5.5W_0.5Mo_0.5O_11.25-δ samples. For all samples the electrical conductivity values measured in a humid atmosphere (up to ~ 10^?3 S/cm at 550?°C) exceed those measured in a dry atmosphere indicating the proton character of conductivity.     

Investigation of the Electronic Structure of Y2Cu2O5–xSx(x — 0.0, 0.25, 0.75) by X-ray Emission Spectroscopy and Xα Scattered Wave Calculation Methods

The investigation of the electronic properties of various copper oxides, containing structural fragments with specific Cu-O polyhedra, has been carried out. The electronic structure of Y₂Cu₂O_5–xS_x compounds (x = 0.0, 0.25, 0.75) has been studied by X-ray emission spectroscopy and the X_α scattered wave (SW) method of calculation. It is shown that substituting apical oxygen by sulfur in the squarepyramid fragments in high-temperature superconductors will result in a decrease of the density of hole carriers in "superconducting" grids of CuO₂ and in the suppression of superconductivity .     

Steam reforming of dimethyl ether using a membrane-catalytic reactor

It has been found that during the steam reforming of dimethyl ether into synthesis gas using a porous ceramic Ni–Co-containing membrane catalytic converter, an increased hydrogen yield with H₂/CO = 15–20 is reached at T = 450–500°C. Reforming in a hybrid membrane reactor with a Pd–Ru alloy membrane integrated into the reaction volume provides recovery of ultrapure hydrogen up to 50% at a temperature of 500–700°C.     

Fluoroplast Doped by Ag2O Nanoparticles as New Repairing Non-Cytotoxic Antibacterial Coating for Meat Industry

Foodborne infections are an important global health problem due to their high prevalence and potential for severe complications. Bacterial contamination of meat during processing at the enterprise can be a source of foodborne infections. Polymeric coatings with antibacterial properties can be applied to prevent bacterial contamination. A composite coating based on fluoroplast and Ag₂O NPs can serve as such a coating. In present study, we, for the first time, created a composite coating based on fluoroplast and Ag₂O NPs. Using laser ablation in water, we obtained spherical Ag₂O NPs with an average size of 45 nm and a ζ-potential of −32 mV. The resulting Ag₂O NPs at concentrations of 0.001–0.1% were transferred into acetone and mixed with a fluoroplast-based varnish. The developed coating made it possible to completely eliminate damage to a Teflon cutting board. The fluoroplast/Ag₂O NP coating was free of defects and inhomogeneities at the nano level. The fluoroplast/Ag₂O NP composite increased the production of ROS (H₂O₂, OH radical), 8-oxogualnine in DNA in vitro, and long-lived active forms of proteins. The effect depended on the mass fraction of the added Ag₂O NPs. The 0.01–0.1% fluoroplast/NP Ag₂O coating exhibited excellent bacteriostatic and bactericidal properties against both Gram-positive and Gram-negative bacteria but did not affect the viability of eukaryotic cells. The developed PTFE/NP Ag₂O 0.01–0.1% coating can be used to protect cutting boards from bacterial contamination in the meat processing industry.     

Characteristics of cleavage fracture during interaction of nonlinear waves with the free surface of a copper single crystal

A molecular dynamics method was used to study the interaction of isolated compression pulses with the (100) and (110) free surface in a copper monocrystallite. It is shown that this may be accompanied by cleavage fracture. Parameters of compression pulses which lead to cleavage processes are determined. Pis’ma Zh. Tekh. Fiz. 25, 22–27 (December 12, 1999)