New approach to describe two coupled spins in a variable magnetic field

We propose a method to describe the evolution of two spins coupled by hyperfine interaction in an external time-dependent magnetic field. We apply the approach to the case of hyperfine interaction with axial symmetry, which can be solved exactly in a constant, appropriately oriented magnetic field. In order to treat the nonstationary dynamical problem, we modify the time-dependent Schr\"odinger equation through a change of representation that, by exploiting an instantaneous (adiabatic) basis makes the time-dependent Hamiltonian diagonal at any time instant. The solution of the transformed time-dependent Schr\"odinger in the form of chronologically ordered exponents with transparent pre-exponential coefficients is reported. This solution is highly simplified when an adiabatically varying magnetic field perturbs the system. The approach here proposed may be used for the perturbative treatment of other dynamical problems with no exact solution

Sustainable development in the regions of the Russian Federation: socio-economic aspect

The article discusses the implementation of the concept of sustainable development, carried out within the framework of the corresponding target model, based on the principle of balancing economic, social and environmental development. The role of the economic block is decisive in the implementation of the target model of sustainable development. At the same time, social and environmental components act to a certain extent in the role of constraints and setting goals for economic development. What are the key goals of the economic block within the framework of the concept of sustainable development of society: ensuring employment of the population with decent wages, solving the problems of creating a safe and favorable climate for the socio-cultural development of society; creation of acceptable conditions for the preservation of the natural environment, capable of meeting the corresponding needs of present and future generations

Synthesis of novel lanthanide acylpyrazolonato ligands with long aliphatic chains and immobilization of the Tb complex on the surface of silica pre-modified via hydrophobic interactions

Five new complexes Ln(QC17)3(H2O)(Solv) (Ln = Y, Solv = H2O, Ln = Tb, Dy, Sm or Eu, Solv = EtOH) were synthesized with the acylpyrazolonato ligand QC17 bearing a long aliphatic C17H35 chain in the acyl moiety, and the crystal structure of Y(QC17)3(H2O)2 shows the three aliphatic chains from the coordinated ligands positioned in the same direction, affording plane layers built by Y(QC17)3(H2O)2 molecules connected through H-bonding interactions. The layers are stitched to each other like in “hook & loop” tapes. Luminescence of complexes was determined and the complex Tb(QC17)3(H2O)(EtOH) was immobilized on the surface of silica preprocessed using a C17H35CONH(CH2)3Si(OEt)3 reagent via hydrophobic interactions of long aliphatic chains. Luminescent properties and micromorphology of the obtained hybrid particles and hybrid films were investigated. Intensive green emission of the complex retains after grafting onto the silica surface. Inclusion of the complex on the surface of silica materials occurs as separate molecules, after the disruption of the H-bonding network present in the crystalline phase of the pure terbium sample

Palladium Powders Specific Surface Estimation by Method of Cyclic Voltammetry

Методом циклической вольтамперометрии исследованы порошки палладия в соляно-кислых растворах. Подобран режим, позволяющий получать катодные пики на ЦВА-кривых с использованием в качестве рабочего электрода порошков палладия с различной степенью дисперсности. По площади катодных пиков были определены удельные площади поверхности исследуемых порошков, значения которых хорошо согласуются с результатами по газовой адсорбции.Palladium powders in muriatic solutions were investigated by a method of cyclic voltamperometry. A regime to obtain cathode peaks in cyclic voltamperometry curves with using varied dispersity palladium powders as main electrode was selected. Specific surfaces of palladium powders were estimated from cathode peaks areas. Obtained results are in well accordance with nitrogen adsorption data

Palladium Powders Specific Surface Estimation by Method of Cyclic Voltammetry

Методом циклической вольтамперометрии исследованы порошки палладия в соляно-кислых растворах. Подобран режим, позволяющий получать катодные пики на ЦВА-кривых с использованием в качестве рабочего электрода порошков палладия с различной степенью дисперсности. По площади катодных пиков были определены удельные площади поверхности исследуемых порошков, значения которых хорошо согласуются с результатами по газовой адсорбции.Palladium powders in muriatic solutions were investigated by a method of cyclic voltamperometry. A regime to obtain cathode peaks in cyclic voltamperometry curves with using varied dispersity palladium powders as main electrode was selected. Specific surfaces of palladium powders were estimated from cathode peaks areas. Obtained results are in well accordance with nitrogen adsorption data

l‑Alanine/Nickel-Induced Size Sorting of Lanthanide(III) Ions in 4f–4f′ Heterometallic Complexes

A versatile approach to create a novel class of mixed-lanthanide compounds with predetermined locations of different lanthanides in cationic and anionic positions has been developed. Pure 4f–4f′ heterometallic complexes were constructed from two independent building blocks: the complex cation [Ln­{Ni­(ala)₂}₆]³⁺ (ala = l-alaninate), which can be formed by La³⁺, Ce³⁺, Pr³⁺, and Nd³⁺ exclusively, and the anion [Gd­(NO₃)₃(OH)₃(H₂O)]^3–. The compositions and structures of the complexes were studied by X-ray crystallography, energy-dispersive X-ray spectroscopy, and inductively coupled plasma mass spectrometry. The X-ray structural analysis showed the high rigidity of the l-alanine/Ni­(II) supramolecular unit in the complex cations, which affected immediately its selectivity toward certain lanthanides