Nukus, Uzbekistan

Karakalpak State University

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Nukus, Uzbekistan
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Matchanov A.D.,Academy of Sciences of Uzbekistan | Dalimov D.N.,Academy of Sciences of Uzbekistan | Zainutdinov U.N.,National University of Uzbekistan | Vypova N.L.,Academy of Sciences of Uzbekistan | And 2 more authors.
Chemistry of Natural Compounds | Year: 2017

Molecular associates of lagochilin and lagochirsine with glycyrrhizic acid and its monoammonium salt in various molar ratios were prepared. Their IR spectra, several physicochemical properties, and hemostatic activities were discussed. © 2017 Springer Science+Business Media, LLC


Ayupov S.,National University of Uzbekistan | Kudaybergenov K.,Karakalpak State University
Journal of Physics: Conference Series | Year: 2016

The paper is devoted to 2-local derivations on matrix algebras over unital semi-prime Banach algebras. For a unital semi-prime Banach algebra A with the inner derivation property we prove that any 2-local derivation on the algebra M 2n (A), n ≥ 2, is a derivation. We apply this result to AW∗-algebras and show that any 2-local derivation on an arbitrary AW∗-algebra is a derivation. © Published under licence by IOP Publishing Ltd.


Mirsagatov S.A.,Academy of Sciences of Uzbekistan | Ataboev O.K.,Karakalpak State University | Zaveryukhin B.N.,Academy of Sciences of Uzbekistan | Nazarov Z.T.,Navoi State Mining Institute
Semiconductors | Year: 2014

A photosensitive structure with high room-temperature integrated sensitivity S int ≈ 700 A/lm (14500 A/W) is fabricated based on alloys of II-VI compounds n-CdSxTe1 - x and p-ZnyCd1 - yTe. Its photoelectric properties are studied at various illumination levels and bias voltages. It is found that diffusion and drift flows of nonequilibrium carriers are directed oppositely at low illumination levels and forward bias voltages. This effect leads to inversion of the photocurrent sign, which makes it possible to fabricate selective photodetectors with injection properties on its basis. © 2014 Pleiades Publishing, Ltd.


Moskalkov M.N.,National Aviation University | Utebaev D.,Karakalpak State University
Cybernetics and Systems Analysis | Year: 2011

The Dirichlet boundary-value problem for the equation of internal waves is considered. To solve it, the finite-element method for both space and time variables is selected. This allows obtaining a highly accurate solution. The accuracy of the method is estimated making certain assumptions on the smoothness of the solutions to the differential problem. If piecewise-cubic finite elements are used, the order of accuracy equals three. © 2011 Springer Science+Business Media, Inc.


Zhanibekov A.A.,Academy of Sciences of Uzbekistan | Naubeev T.Kh.,Karakalpak State University | Uteniyazov K.K.,Karakalpak State University | Bobakulov K.M.,Academy of Sciences of Uzbekistan | Abdullaev N.D.,Academy of Sciences of Uzbekistan
Chemistry of Natural Compounds | Year: 2013

The structure of a new cycloartane triterpene glycoside, cyclolehmanoside C, that was isolated from the aerial part of Astragalus lehmannianus Bunge (Leguminosae) was established as 20R,24S-epoxycycloartane-3β,6α, 16β,24-tetraol 3-O-[β-D-glucopyranosyl(1→2)]- β-D-glucopyranoside-25-O-β-D-glucopyranoside. © 2013 Springer Science+Business Media New York.


Ayupov S.A.,Academy of Sciences of Uzbekistan | Kudaybergenov K.K.,Karakalpak State University
Infinite Dimensional Analysis, Quantum Probability and Related Topics | Year: 2010

The present paper is a survey of recent results concerning derivations on various algebras of measurable operators affiliated with von Neumann algebras. A complete description of derivation is obtained in the case of type I von Neumann algebras. A special section is devoted to the Abelian case, namely to the existence of nontrivial derivations on algebras of measurable function. Local derivations on the above algebras are also considered. © 2010 World Scientific Publishing Company.


Mirsagatov S.A.,Academy of Sciences of Uzbekistan | Uteniyazov A.K.,Karakalpak State University
Technical Physics Letters | Year: 2012

Photosensitive large-block p-type cadmium telluride (p-CdTe) film with a resistivity of ρ ≈ 10 6-10 7 Ω cm has been used to create an Al-p-CdTe-Mo structure with a Schottky barrier, which exhibits the properties of an injection photodiode. Being switched in the forward current passage direction (with "+" on the Mo contact) at high illumination levels, the proposed structure exhibits a responsivity of S λ ≈ 2.6 A/W at a wavelength of λ = 0.625 μm, which is about five times the spectral response of the ideal photodetector for this wavelength range. © 2012 Pleiades Publishing, Ltd.


Kaniyazov S.K.,Karakalpak State University | Muratov A.S.,Karakalpak State University
Radioelectronics and Communications Systems | Year: 2011

The paper deals with complex differential conductivity of multi-layer heterostructures, having N-type characteristics in case of field application along layers boundary. Frequency dependence of real and imaging parts of complex conductance is defined. Diode is characterized with capacity properties and greatQ-factor. It is possible to use these structures for generation of electrical oscillations. © Allerton Press, Inc., 2011.


Naubeev T.Kh.,Academy of Sciences of Uzbekistan | Uteniyazov K.K.,Karakalpak State University | Isaev M.I.,Academy of Sciences of Uzbekistan | Kachala V.V.,RAS Institute of Organic Chemistry | Shashkov A.S.,RAS Institute of Organic Chemistry
Chemistry of Natural Compounds | Year: 2012

The new cycloartane glycoside cycloquivinoside A, 24S-25-methoxycycloartan- 3β,6α,16β,24,25-pentaol 3-O-β-D-glucopyranoside, was isolated from the aerial part of Astragalus chivensis Bunge (Leguminosae). The structure was established based on chemical transformations and 2D spectra (TOCSY, ROESY, HMBC, HSQC, COSY). © 2012 Springer Science+Business Media New York.


Mirsagatov S.A.,Academy of Sciences of Uzbekistan | Leiderman A.Y.,Academy of Sciences of Uzbekistan | Ataboev O.K.,Karakalpak State University
Physics of the Solid State | Year: 2013

Photosensitive In-n +-CdS-n-CdSxTe1 - x-p-ZnxCd1 - xTe-Mo film structures based on II-VI semiconductors and operating in the wavelength range λ = 0.490-0.855 μm have been fabricated. These structures in the forward current direction at high bias voltages operate as injection photodiodes and exhibit a high integrated sensitivity S int ≈ 700 A/lm (14500 A/W) at room temperature. It has been found that, in the fabricated structures at low illuminance levels and low forward bias voltages (0.05-0.50 V), the diffusion and drift fluxes of nonequilibrium charge carriers are directed toward each other. This effect leads to the sign reversal of the photocurrent, which makes it possible on the basis of these structures to create selective photodetectors with injection properties. In the reverse direction of the photocurrent, these structures also operate in the mode of internal amplification of the primary photocurrent, but the integrated sensitivity in this mode is considerably less than that in the forward current direction. © 2013 Pleiades Publishing, Ltd.

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