Lattice Dynamics of Bi2Те3 and Vibrational Modes in Raman Scattering of Topological Insulators MnBi2Te4·n(Bi2Te3)

JETP Letters - This work is devoted to the experimental study and symmetry analysis of the Raman-active vibration modes in MnBi2Te4·n(Bi2Te3) van der Waals topological insulators, where n is...     

Synthesis of Mg-Doped TiO2 nanoparticles under different conditions and its photocatalytic activity

In this study, TiO(2)- and Mg-doped TiO(2) nanoparticles with different dopant contents were prepared by sol-gel method. The prepared photocatalysts were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and diffuse reflectance spectroscopy (DRS) techniques. The results of BET analysis indicated a pore diameter of 8 nm and surface area of 48.5 m(2) g(-1). XRD patterns of pure and doped TiO(2) nanoparticles at 450 °C revealed that all phases are anatase. The particle size obtained from TEM was less than 20 nm. The band gap energy of Mg-doped TiO(2) nanoparticles was lower than that of TiO(2) . The photocatalytic activity of the pure and doped nanoparticles has been compared in the removal of C.I. Acid Red 27 (AR27). The photocatalytic activity of Mg-doped (0.2 mol%) TiO(2) for the degradation of AR27 was higher than that of bare TiO(2) nanoparticles. Results of total organic carbon analysis and changes in the AR27 UV-Vis peaks indicated 99% mineralization and extinguishing of all peaks in UV and visible regions is possible with Mg-doped TiO(2) nanoparticles. Removal efficiency of AR27 was sensitive to the parameters such as catalyst dose, pollutant concentration and light intensity.     

A rapid method of separation and determination of quaternary ammonium compounds involved in carnitine metabolism

The rapid separation of several quaternary ammonium compounds involved in carnitine metabolism is reported. Two convenient methods based on spectrophotometry and liquid scintillation counting are employed to determine the eluting compounds. The application of the techniques to biological determinations is discussed.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-Substituted Oxazolidines and Morpholines

A series of N-substituted oxazolidines and morpholines were prepared and characterized.     

Photoproduction of pairs of neutral fermions with a magnetic moment in the field of a nucleus of arbitrary spin

We have investigated the electromagnetic (Bethe-Heitler) process of the formation of a pair of neutral baryons of spin 1/2 by a photon in the field of a nucleus possessing electric quadrupole and magnetic dipole and octupole moments. The cross section for photoproduction of neutron-antineutron pairs has been found as a function of the electric (Ze, Q) and magnetic (_I, ) multipole moments of the target nucleus. The angular distribution and energy spectrum of the neutron of the pair produced have been studied for⁹Be,¹²C, and⁴⁰Ca nuclei.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 69–75, May, 1982.