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Articles 1 - 18 of 18
Full-Text Articles in Physical Sciences and Mathematics
A Theoretical Study An Influence Of Oxygen Group Elements To Rotational Barrier Of 2-(2'-Pyridyl)-1,3,4-Oxa(Thia, Selena And Tellura) Diazoles, Alisher Eshimbetov, Khamza Toshov, Inderpreet Kaur, Alisher Khaitboev
A Theoretical Study An Influence Of Oxygen Group Elements To Rotational Barrier Of 2-(2'-Pyridyl)-1,3,4-Oxa(Thia, Selena And Tellura) Diazoles, Alisher Eshimbetov, Khamza Toshov, Inderpreet Kaur, Alisher Khaitboev
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
Surveying of the references shows that selenium and tellurium containing compounds will be one of the most promising heterocycles in the future. Therefore, the influence of oxygen group elements -- O, S, Se and Te to rotational barrier heights of 2-(2'-pyridyl)-1,3,4-oxa (thia, selena and tellura) diazoles were investigated by DFT/def2-TZVP method and also by DFT/6-311G(d) method only for O, S and Se series. And also, their thermodynamic parameters (ΔH,ΔG) were calculated in gas phase. Furthermore, some model compounds with conjugated C=C-C=C, N=C-C=C and N=C-C=N fragments with neighbouring chalcogen atoms were considered. It was found that, a rising of barrier heights …
Investigation Of Isomer Ratios In The Reactions (Γ, N) And (N, 2N) On Nuclei 76Ge And 82Se, Satimbay Palvanov, Turgunali Akhmadzhanov
Investigation Of Isomer Ratios In The Reactions (Γ, N) And (N, 2N) On Nuclei 76Ge And 82Se, Satimbay Palvanov, Turgunali Akhmadzhanov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
The method of the induced activity measured the isomeric yield ratios and cross-sections ratios of reactions (γ, n) and (n, 2n) on nuclei 76Ge and 82Se. Samples of natural have been irradiated in the bremsstrahlung beam of the betatron SB-50 of National University of Uzbekistan in the energy range of 10-35 MeV with energy step of 1 MeV. For 14 MeV neutron irradiation, we used the NG-150 neutron generator of Institute of Nuclear Physics. The gamma spectra reactions products were measured with a spectroscopic system consisting of HPGe detector CANBERRA with energy resolution …
Research Of Parabolic Surface Points In Galilean Space, Abdullaaziz Artykbaev, Bekzod Sultanov
Research Of Parabolic Surface Points In Galilean Space, Abdullaaziz Artykbaev, Bekzod Sultanov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
The paper studies the surfaces of the Galilean space $R_3^1$. First, we consider the geometry of the surface in a small neighborhood of a point on the surface. Basically, we studied the points of the surface where at least one of the principal curvature appeals to zero. Two classes of points are defined where at least one of the principal curvature is zero. These points are divided into two types, parabolic and especially parabolic. It is proved that these neighborhoods using the movement of space is impossible to move each other. A sweep of surfaces with parabolic and especially parabolic …
2-Local Derivations On Virasoro Algebras, Shavkat Ayupov, Bakhtiyor Yusupov
2-Local Derivations On Virasoro Algebras, Shavkat Ayupov, Bakhtiyor Yusupov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
The present paper is devoted to study 2-local derivations on infinite-dimensional Lie algebras over a field of characteristic zero. We show that every derivation on Virasoro algebra is inner and prove that all 2-local derivations on this algebra is a derivation. We give an example of infinite-dimensional Lie algebra with a 2-local derivation which is not a derivation.
Bordering Conditions Determination For Nanocomposites Special Properties, Tokhir Rakhimov, Muhtor Mukhamediev, Dilfuza Gafurova
Bordering Conditions Determination For Nanocomposites Special Properties, Tokhir Rakhimov, Muhtor Mukhamediev, Dilfuza Gafurova
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
The paper is devoted to determination of active nanoparticles sizes. Other particles bigger or smaller of calculated size limits are not demonstrated the special activity, on the example of catalytic elimination of environmental pollutants, namely, carbon monoxide, under ambient conditions - low temperature, high humidity, the presence of anthropotoxins. Discusses basic understanding of catalysts used in environmental pollution abatement, in particular, high activity of nanocatalysts with certain sizes and lack of activity of catalysts particles with other sizes. Nevertheless it remains unclear why massive objects containing palladium, as well as true solutions are not effective as catalysts for low-temperature carbon …
Asymptotics Of Solutions And Numerical Simulation Of The Nonlinear Heat Conductivity Problem With Absorption And Variable Density, Mersaid Aripov, Askar Mukimov
Asymptotics Of Solutions And Numerical Simulation Of The Nonlinear Heat Conductivity Problem With Absorption And Variable Density, Mersaid Aripov, Askar Mukimov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In the present work, the asymptotic behavior of the solutions of the nonlinear variable-density thermal conductivity problem with absorption is obtained. The critical value parameter is considered. The resulting asymptotics was used as an initial approximation, numerical calculations were performed. As a difference scheme, a three-layer difference scheme was used, which, unlike a two-layer scheme, has greater accuracy.
Strain Effect On The Electronic Transport Properties Of Carbyne, Gofur Eshonqulov, Golibjon Berdiyorov, Hicham Hamoudi
Strain Effect On The Electronic Transport Properties Of Carbyne, Gofur Eshonqulov, Golibjon Berdiyorov, Hicham Hamoudi
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
Quantum transport calculations are conducted using density functional theory in combination with Green's functional formalism to study the effect of external strain on the electronic transport properties of carbyne, 1D carbon allotrope, which has recently received a revival of interest due to its extraordinary mechanical, thermal and electronic properties. The current in the system increases monotonically by increasing the compressive strain, whereas the tensile strain results in the reduction of the charge transport. The obtained results are explained by spatial variations of the electrostatic potential along the carbon chain and nanoscale localization of the charge carriers. These findings can be …
Ganikhodjaev's Conjecture On Mean Ergodicity Of Quadratic Stochastic Operators, Mansoor Saburov, Khikmat Saburov
Ganikhodjaev's Conjecture On Mean Ergodicity Of Quadratic Stochastic Operators, Mansoor Saburov, Khikmat Saburov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
A linear stochastic (Markov) operator is a positive linear contraction which preserves the simplex. A quadratic stochastic (nonlinear Markov) operator is a positive symmetric bilinear operator which preserves the simplex. The ergodic theory studies the long term average behavior of systems evolving in time. The classical mean ergodic theorem asserts that the arithmetic average of the linear stochastic operator always converges to some linear stochastic operator. While studying the evolution of population system, S.Ulam conjectured the mean ergodicity of quadratic stochastic operators. However, M.Zakharevich showed that Ulam's conjecture is false in general. Later, N.Ganikhodjaev and D.Zanin have generalized Zakharevich's example …
Periodic Table Of Elements, Mendeleev's Periodic Table: History, Achievements And Problems, Boris Oksengendler, Kamil Mukimov, Renat Letfullin, Nigora Turaeva, Gulmurza Abdurakhmanov, Shavkat Yuldashev
Periodic Table Of Elements, Mendeleev's Periodic Table: History, Achievements And Problems, Boris Oksengendler, Kamil Mukimov, Renat Letfullin, Nigora Turaeva, Gulmurza Abdurakhmanov, Shavkat Yuldashev
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
This paper, devoted to the yubilee of Mendeleev's table, deals with a set of historical and physico-chemical problems related it. Basing on the evolutional approach to the development of the concept of “elements and structure” and up to the appearance of the notion “complexity” we discuss the applicability of Mendeleev's table to the understanding of modern aspects of science such as “nano”, “fractals”, “synergetics” and “hirality”. The problems which are open for further research are revealed and the particular importance of their development for the condensed matter science of living and nonliving matter is pointed out.
Convergence Analysis Of Feedforward Neural Networks With Backpropagation, Avazjon Marakhimov, Kabul Khudaybergenov
Convergence Analysis Of Feedforward Neural Networks With Backpropagation, Avazjon Marakhimov, Kabul Khudaybergenov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this paper, convergence analysis properties of online gradient training for backpropagation algorithm for feedforward neural networks with a two hidden layer is studied. We assume that in every training cycle, every training pattern in the training dataset is fed in a stochastic form to the feedforward multilayer neural network exactly once. In this study, we give a weak and strong convergence properties for the training approaches, indicating that the gradient of the error function goes to zero and the weights goes to a fixed point value, respectively. First, we give convergence result for completely stochastic order approach and then …
Test Particle Motion Around Brany Black Hole Immersed In An External Asymptotically Uniform Magnetic Field, Djavlanbek Rayimbaev, Azamjon Rakhmatov, Satimbay Palvanov, Ahror Mamadjanov
Test Particle Motion Around Brany Black Hole Immersed In An External Asymptotically Uniform Magnetic Field, Djavlanbek Rayimbaev, Azamjon Rakhmatov, Satimbay Palvanov, Ahror Mamadjanov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
We investigate circular motion of charged and neutral particles around non-rotating black hole immersed in an external asymptotically uniform magnetic field. The effects of braneworlds on innermost circular stable orbits have been considered. Shown that innermost circular orbits (ISCO) decreases in decreasence of both brane charge and particle charge. Moreover, we have investigated energy extraction from black holes in braneworld through collision of two particles. Obtained that the presence of the brane charge parameter causes to decrease of the value of center of mass energy of colliding two charged particles, it means the brane charge acts as an additional gravity.
Oscillatory Integrals And Weierstrass Polynomials, Azimbay Sadullaev, Isroil Ikromov
Oscillatory Integrals And Weierstrass Polynomials, Azimbay Sadullaev, Isroil Ikromov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this work we consider some applications of the Weierstrass preparation theorem and Weierstrass pseudopolynomials to study of behavior of the oscillatory integrals and Fourier transforms with analytic and smooth phases with critical points.
Sarymsakov Cubic Stochastic Matrices, Mansoor Saburov, Khikmat Saburov
Sarymsakov Cubic Stochastic Matrices, Mansoor Saburov, Khikmat Saburov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
The class of Sarymsakov square stochastic matrices is the largest subset of the set of stochastic, indecomposable, aperiodic (SIA) matrices that is closed under matrix multiplication and any infinitely long left-product of the elements from any of its compact subsets converges to a rank-one (stable) matrix. In this paper, we introduce a new class of the so-called Sarymsakov cubic stochastic matrices and study the consensus problem in the multi-agent system in which an opinion sharing dynamics is presented by quadratic stochastic operators associated with Sarymsakov cubic stochastic matrices.
Topological Properties Of Hyperspaces, Ruzinazar Beshimov, Dilnora Safarova
Topological Properties Of Hyperspaces, Ruzinazar Beshimov, Dilnora Safarova
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In the work, it is given the normal functor F acting in the category of compacts and their continuous mappings. This functor does not preserve the Souslin number (or hereditary cellularity), the hereditary density, the hereditary π-weight and the hereditary Shanin number, the hereditary caliber, the hereditary precaliber, the hereditary preshanin number, the hereditary weak density, the hereditary Lindelöf number, and the hereditary extent of a compact. The example of the normal functor and the compact of Aleksandorv's two arrows are given. We study the action of functors expn, expω, expc and exp on …
The Waiting Time And Dynamic Partitions, Akhtam Dzhalilov, Mukhriddin Khomidov
The Waiting Time And Dynamic Partitions, Akhtam Dzhalilov, Mukhriddin Khomidov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In the present paper we study the behaviour of normalized waiting times for linear irrational rotations. D.Kim and B.Seo investigated the waiting times for equidistance partitions. We consider waiting times with respect to dynamical partitions. The results show that limiting behaviour of waiting times essentially depend on type of partitions.
Solvable Leibniz Superalgebras Whose Nilradical Is A Lie Superalgebra Of Maximal Nilindex, Abror Khudoyberdiyev, Manuel Ladra, Khosiat Muratova
Solvable Leibniz Superalgebras Whose Nilradical Is A Lie Superalgebra Of Maximal Nilindex, Abror Khudoyberdiyev, Manuel Ladra, Khosiat Muratova
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this paper, we investigate solvable Leibniz superalgebras whose nilradical is a Lie superalgebra with maximal nilindex.It should be noted that Lie superalgebra with a maximal nilindex only exists in the variety of Lie2,m when m is odd. We give the classification of all solvable Leibniz superalgebras such that even part is a Lie algebra and nilradical is a Lie superalgebra with a maximal index of nilpotency.
On The Continuation Of The Hartogs Series With Holomorphic Coefficients, Takhir Tuychiev, Jurabay Tishabaev
On The Continuation Of The Hartogs Series With Holomorphic Coefficients, Takhir Tuychiev, Jurabay Tishabaev
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this paper we consider the question of continuation of the sums of the Hartogs series that admit holomorphic continuation along a fixed direction with “thin” singularities, assuming only the holomorphic of the coefficients of the series and investigate the convergence region of such series. The results of the work develop a well-known result of A.Sadullaev and E.M.Chirka on the continuation of functions with polar singularities.
On A Control Problem Associated With Fast Heating Of A Thin Rod, Shavkat Alimov, Farrukh Dekhkonov
On A Control Problem Associated With Fast Heating Of A Thin Rod, Shavkat Alimov, Farrukh Dekhkonov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this work, we consider boundary control problem associated with a parabolic equation on a interval. On the part of the border of the considered segment, the value of the solution with control parameter is given. Restrictions on the control are given in such a way that the average value of the solution in some part of the considered interval gets a given value. The auxiliary problem is solved by the method of separation of variables, while the problem in consideration is reduced to the Volterra integral equation of the second kind. The control parameter is defined on one. The …