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© 2016 Elsevier B.V.The EPR spectrum of the Ce3+ ion in the crystal of the elpasolite type Rb2NaYF6 has been observed and studied at low temperatures (Т = 4.2 – 80 K). It was established that the paramagnetic center Ce3+ has tetragonal symmetry confirming the experimental fact we reported recently that at low temperatures the Rb2NaYF6 crystal exists in the tetragonal phase, into which it transferred from the cubic phase as a result of the structural phase transition (PT). Parameters of the spin Hamiltonian of the tetragonal EPR spectrum were determined. A scheme of 4f energy levels of the Ce3+ ion in Rb2NaYF6 before and after PT was proposed from the theoretical interpretation of the observed g-factors and parameters of the crystal fields acting on it were determined.

© Published by Elsevier Ltd. The paramagnetic center of tetragonal symmetry formed by the Yb3+ ion in the KZnF3 crystal has been studied using methods of EPR, ENDOR and optical spectroscopy. The location of the impurity ion and the structural model of the complex differing from the model of the Yb3+ center in KMgF3 have been established. The empirical scheme of the energy levels of the Yb3+ ion has been found. The parameters of its interaction with the crystal electrostatic field and the hyperfine interaction with ligands of the nearest environment have been determined. The parameters of the crystal field were used for the analysis of the distortions of the crystal lattice in the vicinity of Yb3+. The parameters of the transferred hyperfine interaction have been calculated for the distances between Yb3+ and F- ions of the nearest environment obtained taking into account the found distortions. They are in good agreement with the experimental values.

CsCaF3 crystals doped with Yb3+ ions have been studied using the electron paramagnetic resonance and optical spectroscopy methods. Several types of paramagnetic Yb3+ centers were found, among which a paramagnetic center in the unusual position was established. The parameters of the corresponding spin Hamiltonians and schemes of the energy levels of the observed centers were determined. © 2014 Springer-Verlag Wien.

The structural phase transition has been observed for the first time in the Rb2NaYF6 crystal and studied by EPR and optical spectroscopy. EPR spectra of Dy3+ and Yb3+ ions present as unintentional dopants in the nominally undoped crystal and forming tetragonal paramagnetic centers have been identified. A characteristic splitting of some optical lines has been observed in the temperature dependence of the Yb3 + optical spectra. It indicates the splitting of the cubic quartet energy levels of Yb3+ ions by the tetragonal crystal field. The empirical schemes of the energy levels for cubic and tetragonal paramagnetic centers of Yb3+ ions have been established and parameters of the corresponding crystal fields have been determined. The latter have been used for analyzing the crystal lattice distortions occurring in the vicinity of the Yb3+ ion during the phase transition. It has been established using the superposition model that the nearest octahedral environment of the Yb3 + ion is distorted as follows: the fluorine ions are rotated by the angle of 2.1 around the fourfold axis; the F- ions located symmetrically in the plane perpendicular to the rotation axis approach the dopant by 0.0014 nm, whereas the F- ions located on the rotation axis move away by 0.0028 nm. It has been concluded that the studied phase transition includes the critical rotations of the octahedral F groups and noncritical displacement of atoms in the rotated fluorine octahedra. © 2013 American Physical Society.

Paramagnetic Tm 2+ ion centers in the KMgF 3 single crystal have been studied by electron paramagnetic resonance and optical spectroscopy. The Stark level energies of the cubic Tm 2+ multiplets have been established from the luminescence spectra and the crystal field parameters have been calculated. Information about the phonon spectra of KMgF 3 crystals has been obtained from the electron-vibrational structure of the optical luminescence spectra. © 2012 Elsevier B.V. All rights reserved.

A trigonal Yb3+ paramagnetic center in the CsCaF3 single crystal was studied by magnetic resonance and optical spectroscopy methods. The structural model of the complex and the empirical energy level scheme were established. The transferred hyperfine interaction parameters and the crystal field ones were determined. The crystal field parameters were used to analyze the lattice distortions in the vicinity of Yb3+ using the superposition model. © 2010 Springer-Verlag.

Приводятся результаты экспериментальных исследований, проведенных с целью уточнения математических зависимостей, описывающих процесс нейтрализации бетона на примере среды углекислого газа. In the article the results of the experiments carried out with the aim of clarification of mathematical relation describing a concrete carbonization process with the carbon dioxide shielded taken as an example are given.

Проведен анализ 615 пациентов с различной патологией щитовидной железы. Процент послеоперационного гипопаратиреоза составил 1,14 %. С целью профилактики послеоперационного гипопаратиреоза в эксперименте разрабоана методика эндовазальной аутотрансплантации случайно удаленных или лишенных кровоснабжения околощитовидных желез. The analysis of 615 patients with various thyroid disorders was carried out. The percentage of postoperative hypoparathyroidism amounted 1,14%. In order to prevent postoperative hypoparathyroidism in the course of experiment, the method of endovascular autotransplantation of accidentally removed or deprived of supply parathyroid glands was developed. Попов О.С., доктор медицинских наук, профессор, заведующий клиникой общей хирургии Сибирского государственного медицинского университета (Томск); тел. 8-382-2531125. Popov O.S., doctor of medical science, professor, Head of General Surgery clinic of Siberian State Medical University (Tomsk); ph. 8-382-2531125. Лян Н.И., ординатор кафедры общей хирургии Сибирского государственного медицинского университета (Томск); тел. 8-923-4120433; e-mail:nikolay.lyan@gmail.com Lyan N.I., resident doctor of General Surgery department of Siberian State Medical University (Tomsk);ph. 8-923-120433; e-mail: nikolay.lyan@gmail.com. Ларионов М.М., ординатор кафедры общей хирургии Сибирского государственного медицинского университета (Томск); e-mail:larri902on@list.ru Larionov M.M., resident doctor of General Surgery department of Siberian State Medical University (Tomsk); e-mail: larri902on@list.ru. Галян А.Н., кандидат медицинских наук, ассистент кафедры общей хирургии Сибирского государственного медицинского университета, врач-хирург клиники общей хирургии Сибирского государственного медицинского университета (Томск);тел. 8-903-9544222; e-mail: Angalyan@yandex.ru.Galyan A.N., candidate of medical science, assistant of General Surgery department of Siberian State Medical University, surgeon of General Surgery clinic of Siberian State Medical University (Tomsk);ph. 8-903-9544222; e-mail: Angalyan@yandex.ru. Латыпов В.Р., доктор медицинских наук, заведующий отделением общей хирургии (Томск). Latypov V.R., doctor of medical science, Head of General Surgery department (Tomsk). Гаспарян С.Н., врач УЗИ диагностики Научно-исследовательского института фармакологии Сибирского отделения РАМН (Томск). Gasparyan S.N., ultrasonographer of Research Institute of Pharmacology of Siberian department of Russian Academy of Medical Sciences (Tomsk). Байков А.Н., доктор медицинских наук, профессор, заведующий центральной научно-исследовательской лабораторией Сибирского государственного медицинского университета (Томск). Baykov A.N., doctor of medical science, professor, Head of Central Reseach laboratory of Siberian State Medical University (Tomsk). Удут В.В., заместитель директора по науке и лечебной работе Научно-исследовательского института фармакологии Сибирского отделения РАМН (Томск). Udut V.V., deputy director of science and clinical care of Research Institute of Pharmacology of Siberian department of Russian Academy of Medical Sciences (Tomsk).

The results of an electron-nuclear double resonance study of the cubic paramagnetic Yb3+ center in Cs2 NaY F6 and CsCa F3 single crystals are presented. The values and signs of the transferred hyperfine interaction (THFI) parameters for several neighboring shells are determined. It is found that the relevant parameters for the two studied matrices differ, in spite of the fact that the nearest environment of the rare earth ion is nearly identical. A first-principles theoretical analysis is performed for the THFI parameters of the first coordination shell of F- ions. Several mechanisms of metal ion-ligand coupling are considered and it is found that one of them, ligand polarization, explains the difference observed for the THFI parameters in Cs2 NaY F6 and CsCa F3. © 2009 The American Physical Society.

CaF2 crystals doped with Yb3+ ions have been studied by electron paramagnetic resonance (EPR) and optical spectroscopy. EPR spectra of paramagnetic centers (PCs) for cubic (Tc) and tetragonal (T tet) symmetries were identified. Empirical energy level diagrams were established and crystal field parameters were determined. Information on the CaF2:Yb3+ phonon spectra was obtained from the electron-vibrational structure of the optical spectra. The crystal field parameters were used to analyze the crystal lattice distortions in the vicinity of the Yb3+ ion. Within the framework of a superposition model, it is established that four F- ions located symmetrically with respect to the fourfold axis from the side of the ion-compensator approach the impurity ion and deviate from the PC axis. The second set of four fluorine ions also approaches the Yb3+ ion and the PC axis. The ion-compensator F - also approaches considerably the impurity ion.