Репозиторий Университета

© 2019 Elsevier B.V. The formation of novel ternary cerium germanide with the chemical composition Ce33.3Ir22.2Ge44.5 (at.%) was established. As derived from powder X-ray diffraction data, the compound crystallizes with two polymorphic modifications. The high-temperature modification, established for as-cast alloy, possesses a tetragonal ThSi2-type structure and can be named as Ce(IrxGe1-x)2, x = 0.32. The low-temperature modification forms in the course of heat treatment at 1073 K, crystallizes with an orthorhombic structure of its own type and can be labeled as Ce3Ir2-xGe4+x, x = 0.02. Both structures belong to the AlB2 structural family and are closely related to each other. In both modifications, statistical mixtures of Ir and Ge atoms occupy same crystallographic sites. As found by means of magnetization measurements, the two structural variants of Ce33.3Ir22.2Ge44.5 (at.%) exhibit very similar magnetic properties. Both polymorphs are Curie-Weiss paramagnets with strong crystalline electric field features observed at low temperatures.

© 2019 Elsevier B.V. SERS substrate containing SERS-active array of Ag, Au and Ag50Au50 nanoparticles with normal size distribution, a mirror layer and a separating SiO2 layer was optimized. A layer of amorphous carbon was used as the object of study. It is shown that such a structure enhances the Raman signal both due to the localized surface plasmon resonance and due to interference. The average size of nanoparticles, the reflection coefficient of mirror layer, and the thickness of SiO2 layer influence the amplification of the Raman signal. To provide amplification the thickness of SiO2 layer should be calculated for the appropriate wavelength in order to get constructive interference. It is revealed that additional amplification of the Raman signal occurs if the mirror layer as well as the array of particles is made of plasmon metal and thickness of separating SiO2 layer is quite small (up to 30 nm).

©. 2018, Current Science Association, Bengaluru. All Rights Reserved. The present communication aims at determining an optimum method of manufacture of orthopaedic arch titanium alloy dentures that would not cause galvanosis in patients using such dentures. A clinical randomized controlled retrospective study was conducted. Sixty patients who used arch titanium alloy dentures were examined. Three measurements of electrochemical potentials in various areas of the oral cavity were done in all patients, using a biopotentiometer. Linear prediction of differences in potentials in measurement areas 1-3 for the control group (CG) of patients exhibited minor growth dynamics, which can be indicative of the risk of galvanosis in CG patients in the future.

© 2018 Trans Tech Publications, Switzerland  This paper presents the results of experimental studies of arrays of Ag 0.52 Au 0.48 alloy nanoparticles. Arrays were formed by vacuum-thermal evaporation on an unheated substrate and subsequent low-temperature vacuum annealing. The TEM images of the obtained nanoparticle arrays and corresponding histograms of particle size distribution are shown. The transmission spectra of these arrays showing the displacement of the plasma frequency as a function of the mean particle size are obtained. Spectra of Raman scattering from a thin film of amorphous carbon in presence of AgAu particles are obtained, and a comparative analysis of Raman scattering amplification factors for pure Ag, pure Au and Ag 0.52 Au 0.48 alloy nanoparticles is presented.