Np Ogarev Mordovian State University

Saransk, Russia

Np Ogarev Mordovian State University

Saransk, Russia
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Pynenkov A.A.,Np Ogarev Mordovian State University | Nischev K.N.,Np Ogarev Mordovian State University | Kyashkin V.M.,Np Ogarev Mordovian State University | Tomilin O.B.,Np Ogarev Mordovian State University | And 2 more authors.
Journal of Non-Crystalline Solids | Year: 2017

A series of barium gallium-germanate glasses (84-kh(cyrillic)) GeO2-14BaO-2Ga2O3-x Bi2O3 (kh(cyrillic)=0; 0,1; 1; 3; 5mol%) was synthesized by crucible technology. It was revealed that the appearance of a BaGe4O9 crystalline phase took place after additional thermal treatment of the glass samples. The structural and optical properties of the glasses and glass-ceramics were studied. It was shown that the spectral shapes and the peak positions of the absorption, luminescence and excitation bands strongly depend on the type of materials. In particular, the absorption band peaked at 480 and 660nm is characteristic for the glass samples whereas in the absorption spectrum of the glass-ceramic two bands at 480nm and 560nm were observed. Moreover, with the appearance of a crystalline phase, the luminescence peak shifts towards shorter wavelengths, while its intensity increases. The possible states of Bi ions in the BaGe4O9 crystalline phase were calculated using a molecular cluster model. The obtained results indicate that an incorporated in the crystalline phase Bi+ ion could be considered as a possible near IR luminescence source. © 2017 Elsevier B.V.


Vasin V.A.,Np Ogarev Mordovian State University | Masterova Yu.Yu.,Np Ogarev Mordovian State University | Razin V.V.,Saint Petersburg State University | Somov N.V.,Novgorod State University
Canadian Journal of Chemistry | Year: 2013

Methyl-, phenyl-, p-chlorophenyl-, and p-tolyl(phenylethynyl)sulfones under photochemical or thermal initiation add to the central bicyclobutane C1-C7 bond of 1-R(H, Me, Ph)-tricyclo[4.1.0.02,7]heptanes anti-selectively, and form norpinic adducts containing a phenylethynyl group in a geminal to substituent R position, and an endo-oriented sulfonyl group in position 7. The corresponding ketones were prepared by the hydration of the anti-adducts by the method of Kucherov. The ketone with a methylsulfonyl substituent under reflux in toluene in the presence of KOH powder and the phase-transfer catalyst (TEBA-Cl) afforded the tricyclic sulfone. © 2013 Published by NRC Research Press.


Sobenin I.A.,Russian Academy of Medical Sciences | Korneev N.V.,Nn Burdenko Main Military Clinical Hospital | Romanov I.V.,25Th Central Military Clinical Hospital of Strategic Rocket Forces | Shutikhina I.V.,Russian Academy of Medical Sciences | And 5 more authors.
Experimental and Clinical Cardiology | Year: 2014

This study was designed to estimate the effect of time-released garlic powder tablets Allicor on the progression of carotid atherosclerosis in 211 asymptomatic men aged 40-74 in double-blinded placebo-controlled clinical trial. The primary outcome was the rate of atherosclerosis progression, measured by B-mode ultrasonography as the increase in carotid intima-media thickness (cIMT). In Allicor-treated group the decrease of cIMT by 0.028±0.008 mm was observed, whereas in placebo group there was a moderate progression at the rate of 0.014±0.009 mm per 12 months (P=0.002 for the difference). Serum atherogenicity (the ability of serum to induce cholesterol accumulation in cultured cells) was lowered in Allicor-treated patients by 45% from the baseline level, on an average. In the placebo group, serum atherogenic potential did not change significantly. These results demonstrate that long-term treatment with Allicor provides a direct antiatherosclerotic effect on subclinical carotid atherosclerosis, and this effect may be due to serum atherogenicity inhibition. © 2013 et al.; licensee Cardiology Academic Press.


Malov A.V.,Np Ogarev Mordovian State University | Ryabochkina P.A.,Np Ogarev Mordovian State University | Popov A.V.,RAS A.M. Prokhorov General Physics Institute | Bol'shakova E.V.,Np Ogarev Mordovian State University
Quantum Electronics | Year: 2010

The processes of nonradiative energy transfer in calcium-niobium-gallium garnet (CNGG) crystals doped with Er3+ ions are studied. It is found that the energy of erbium ions in the Er: CNGG crystal with the erbium atomic concentrations CEr = 6% and 11% is transferred via the nonradiative co-operative processes 4I11/2 →4I 15/2, 4I11/2 → 4F 7/2; 4I11/2→4I15/2, 4I13/2→4F9/2; and 4I13/2→4I15/2, 4I 13/2 → 4I9/2, wh0Se efficiency increases with increasing intensity of exciting radiation. It is shown that the crossrelaxation processes 4S3/2 →4I 9/2, 4I15/2 → 4I 13/2, whose intensity depends on the concentration of Er3+ ions, are characteristic for Er:CNGG crystals with the Er atomic concentration above 1 %. © 2010 Kvantovaya Elektronika and Turpion Ltd.


Bol'Shakova E.V.,Np Ogarev Mordovian State University | Malov A.V.,Np Ogarev Mordovian State University | Ryabochkina P.A.,Np Ogarev Mordovian State University | Ushakov S.N.,RAS A.M. Prokhorov General Physics Institute | Nishchev K.N.,Np Ogarev Mordovian State University
Optics and Spectroscopy (English translation of Optika i Spektroskopiya) | Year: 2011

We examine the oscillator strengths and the intensity parameters Ω t (t = 2, 4, 6) of yttrium-aluminum, scandium-containing, and gallium garnet crystals doped with Er3+ ions. A comparative analysis of the oscillator strengths and the intensity parameters Ω t (t = 2, 4, 6) of garnets with different contents of Al3+ and Sc3+ ions (Gd2.4Er0.5Sc1.8Al3.3O 12, Gd2.4Er0.5Sc1.9Al 3.2O12, Gd2.4Er0.5Sc 2.0Al3.1O12) is performed, as a result of which the oscillator strengths and the intensity parameters Ω t (t = 2, 4, 6) of these crystals are shown to have close values. We find that Ca 3(NbGa)5O12 crystals doped with Er3+ ions are characterized by highest values of the oscillator strengths for hypersensitive transitions and of the intensity parameter Ω2 of Er3+ ions compared to the values of these quantities in the examined garnet crystals, which is determined by the fact that the symmetry of the local environment of Er3+ ions in these crystals is C 1, C 2, or C 2ν. We reveal that, as the concentration of Er3+ ions in these crystals increases from 1 to 39 at %, both the oscillator strength of the hypersensitive transition 4 I 15/2 → 2 H 11/2 of Er3+ ions and their intensity parameter Ω2 tend to decrease, which can be related to an increase in the relative fraction of Er3+ ions with higher symmetry of the local environment. © 2011 Pleiades Publishing, Ltd.


Ryabochkina P.A.,Np Ogarev Mordovian State University | Chabushkin A.N.,Np Ogarev Mordovian State University | Kosolapov A.F.,Fiber Optics Research Center | Kurkov A.S.,RAS A.M. Prokhorov General Physics Institute
Quantum Electronics | Year: 2015

We have obtained the spectral dependences of the absorption cross sections for the Ho3+ 5I8 → 5I6 and 5I8 → 5I7 transitions in Ho3+-doped aluminosilicate fibres and the spectral dependence of the stimulated emission cross section for the Ho3+ 5I7 → 5I8 laser transition in Ho3+-doped aluminosilicate fibre preforms. The lifetime of the Ho3+ 5I7 upper laser level in the preforms has been determined. © 2015 Kvantovaya Elektronika and Turpion Ltd.


Ryabochkina P.A.,Np Ogarev Mordovian State University | Sidorova N.V.,Np Ogarev Mordovian State University | Chabushkin A.N.,Np Ogarev Mordovian State University | Lomonova E.E.,RAS A.M. Prokhorov General Physics Institute
Quantum Electronics | Year: 2016

Experimental results on lasing in ZrO2 - Y2O3 - Er2O3 crystals are presented. Under diode pumping of ZrO2 - Y2O3 (13.8 mol %) - Er2O3 (0.2 mol %) crystals into the 4I13/2 level of Er3+ ions, lasing is obtained at the 4I13/2⇒4I15/2 transition with a wavelength of 1648 nm. © 2016 Kvantovaya Elektronika and Turpion Ltd.


Ryabochkina P.A.,Np Ogarev Mordovian State University | Sidorova N.V.,Np Ogarev Mordovian State University | Ushakov S.N.,RAS A.M. Prokhorov General Physics Institute | Lomonova E.E.,RAS A.M. Prokhorov General Physics Institute
Quantum Electronics | Year: 2014

Yttria-stabilised zirconia crystals ZrO2-Y2O3 (6 mol %)-Er2O3 (5.85 mol %) are grown by directional crystallisation in a cold container using direct RF melting. The spectral and luminescent properties of these crystals are studied in order to use them as active media of solid state lasers emitting in the wavelength range 1.5-1.7 mm. © 2014 Kvantovaya Elektronika and Turpion Ltd.


Ryabochkina P.A.,Np Ogarev Mordovian State University | Chabushkin A.N.,Np Ogarev Mordovian State University | Kopylov Yu.L.,RAS Institute of Radio Engineering and Electronics | Balashov V.V.,RAS Institute of Radio Engineering and Electronics | Lopukhin K.V.,RAS Institute of Radio Engineering and Electronics
Quantum Electronics | Year: 2016

The results of investigation of the spectral, luminescent and lasing properties of Tm: Y2O3 ceramics are presented. Lasing in Y2O3 ceramics is obtained at wavelengths of 1.95 and 2.05 mm. The maximum output laser power at these wavelengths was 2.4 and 0.3 W, respectively. © 2016 Kvantovaya Elektronika and Turpion Ltd.


Melnikova N.,Nizhny Novgorod State Medical Academy | Burlova I.,Np Ogarev Mordovian State University | Kiseleva T.,Nizhny Novgorod State Medical Academy | Klabukova I.,Nizhny Novgorod State Medical Academy | And 4 more authors.
Molecules | Year: 2012

The room temperature oxidation of betulin by Cr(VI) compounds in aqueous acetone on solid supports such as alumina, zeolites and silica gel has been studied. The oxidation on alumina support leaded to a single product-betulonic acid-in quantitative yield. One hundred percent selective oxidation during 30 min of betulin up to betulonic aldehyde was determined when silica gel support was used. The oxidation of betulin using zeolites as a support gives a mixture of betulonic acid and aldehyde in a 2:1 ratio. It is proposed the selective oxidation up to betulonic acid is due to the influence of Al 3+-ions. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

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