Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Mathematics (10)
- Analysis (3)
- Physics (3)
- Chemistry (2)
- Geometry and Topology (2)
-
- Analytical Chemistry (1)
- Applied Mathematics (1)
- Artificial Intelligence and Robotics (1)
- Astrophysics and Astronomy (1)
- Computer Sciences (1)
- Cosmology, Relativity, and Gravity (1)
- Earth Sciences (1)
- Environmental Indicators and Impact Assessment (1)
- Environmental Sciences (1)
- Geology (1)
- Numerical Analysis and Computation (1)
- Organic Chemistry (1)
- Statistics and Probability (1)
- Keyword
-
- Stability (5)
- Difference schemes (3)
- Energetic norm (3)
- Hyperbolic system (3)
- Carleman’s formula (2)
-
- Cauchy kernel (2)
- Cayley tree (2)
- Hyperspace (2)
- Matrix unit disc (2)
- Matrix upper half-plane (2)
- Shilov’s boundary (2)
- $\lambda$-like and BCS-like anomalies (1)
- $k$-spaces (1)
- $n$-permutation degree (1)
- 2 (1)
- 6-disulfonic acid (1)
- 7-dinitrozo-1 (1)
- 8-dihydroxynaphthalene-3 (1)
- Adaptation (1)
- Adjoint operator (1)
- Algorithm (1)
- Anthropogenic factors and the damaged degree (1)
- Application (1)
- Aromatic hydrocarbons (1)
- Benzene solution (1)
- Biological activity (1)
- Boundary conditions (1)
- Canal (1)
- Clusterization (1)
- Conductometric titration (1)
Articles 1 - 21 of 21
Full-Text Articles in Physical Sciences and Mathematics
Ill-Posed Boundary Value Problem For Operator-Differential Equation Of Fourth Order, Kudratillo Fayazov, Ikrom Khajiev, Z. Fayazova
Ill-Posed Boundary Value Problem For Operator-Differential Equation Of Fourth Order, Kudratillo Fayazov, Ikrom Khajiev, Z. Fayazova
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
We prove the correctness of the conditional boundary value problem for an operator differential equation of the fourth order. A priori estimate is get. Uniqueness and conditional stability of solution are proved. The approximate solution is construct and get estimates of the norm of the difference between the exact and approximate solution.
Translation-Invariant Gibbs Measures Of A Model On Cayley Tree, Golibjon Botirov
Translation-Invariant Gibbs Measures Of A Model On Cayley Tree, Golibjon Botirov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
We consider a model where the spin takes values in the set [0,1]d, and is assigned to the vertexes of the Cayley tree. We reduce the problem of describing the “splitting Gibbs measures” of the model to the description of the solutions of some non-linear integral equation. For a concrete form of the Kernel of the integral equation we show the uniqueness of solution.
Analysis Of Clusterization Of C70 Molecules In Benzene Solutions Prepared By Various Methods, U. Makhmanov, O. Ismailova, A. Kokhkharov, S. Bakhramov
Analysis Of Clusterization Of C70 Molecules In Benzene Solutions Prepared By Various Methods, U. Makhmanov, O. Ismailova, A. Kokhkharov, S. Bakhramov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
Self-assembling features of molecules of C70 in benzene solution prepared in two various ways – equilibrium and non-equilibrium – has been investigated experimentally by method of high-resolution transmission electron microscopy. It was demonstrated, that the formation of densely packed monomolecular fullerene aggregates with a diameter of not more than 30 nm in solutions prepared by the equilibrium method (without the use of external mechanical influences on solution). In the case of solutions C70, which were prepared by the non-equilibrium method (stirring of solution of C70 by a mechanical rotator), large quasispherical aggregates of nanoporous structure with …
Electronic Specific-Heat Anomalies In High-TC Cuprates, S. Dzhumanov, E. Karimboev, B. Yavidov
Electronic Specific-Heat Anomalies In High-TC Cuprates, S. Dzhumanov, E. Karimboev, B. Yavidov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this work, we study the electronic specific heat $C_e(T)$ of underdoped to overdoped high-$T_c$ cuprates, and identify the nature of anomalies in $C_e(T)$ at the superconducting transition temperature $T_c$ and at temperatures above $T_c$. The doped cuprate superconductor is considered as a multi-carrier model system which is composed of different types of charge carriers. The normal-state electronic specific heat $C_n(T)$ of high-$T_c$ cuprates below a characteristic pseudogap (PG) temperature $T^*$ is calculated taking into account three contributions coming from the excited components of Cooper pairs, the ideal Bose-gas of incoherent Cooper pairs and the unpaired carriers in the impurity …
Electron Exchange Between Impurity Centers Of Tin In Pbs And Pbse, S. Zaynabiddinov, K. Bobokhujaev
Electron Exchange Between Impurity Centers Of Tin In Pbs And Pbse, S. Zaynabiddinov, K. Bobokhujaev
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
Electron exchange between neutral and doubly ionized U-minus centers of tin in par-tially compensated solid solutions Pb1-xSnxS and Pb1-xSnxSe has been investigated using 119mmSn(119mSn) emission Mössbauer spectroscopy. The activation energy of the process for Pb1-xSnxS solid solutions is 0.11 ± 0.02 eV and is comparable to the depth of energy levels of tin in the PbS band gap, while the activation energy of this process for Pb1-xSnxSe solid solutions is comparable to the activation energy of donor U-minus centers …
Thermal Evolution Modification Due To Radio-Wave Production Inside Rotating Magnetized Ns, Pulat Tadjimuratov
Thermal Evolution Modification Due To Radio-Wave Production Inside Rotating Magnetized Ns, Pulat Tadjimuratov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
We study effect of additional cooling mechanism on the thermal evolution of rotating magnetized neutron star (NS). The influence of general relativistic effects on charge distribution inside a NS leads to the qualitative distinction of space charge distribution inside the conducting crust from that inside the superconducting core which may play a source of a possible mechanism of radio-wave radiation production in the intermediate medium inside a rotating neutron star. This radiation may interact the matter of the neutron star and energy of the electromagnetic radiation can be transformed into the heating energy. The intensity of radio-wave radiation produced inside …
Amidoalkylation Of Aromatic Compounds, Mukhabbat Yuldasheva, Khurshida Turaeva, Tursunali Kholiqov
Amidoalkylation Of Aromatic Compounds, Mukhabbat Yuldasheva, Khurshida Turaeva, Tursunali Kholiqov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
As the result of systematical investigation of amidomethylation reaction benzene, toluene, isomeric xylenes, benzodioxane-1,4, mono- and dimethyl ethers of resorcinole, dimethyl ethers of hydroquinone with methylol and ethylol derivatives amides and imides, acetonitrile, benzonitrile and paraform the amidomethyl derivatives have been obtained and also influence of different factors on their yields and direction of investigated reactions was determined. Synthesis of amidomethyl derivatives of aromatic hydrocarbons, ethers dihydricpenols and most probable reaction mechanism was proposed.
Creation Of A Numerical Mathematical Model Of Geofiltration Processes And Its Adaptation For Solving Epignosic And Forecast Problems (In Terms Of Gurlen District Of Khorezm Region), Tolkun Mirakhmedov
Creation Of A Numerical Mathematical Model Of Geofiltration Processes And Its Adaptation For Solving Epignosic And Forecast Problems (In Terms Of Gurlen District Of Khorezm Region), Tolkun Mirakhmedov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
The article considers the creation of a mathematical model of geofiltration processes in Gurlen District. Methods for calculating and developing a mathematical model and algorithms were carried out, and applied software was developed, and the developed geofiltration mathematical model was adapted to solve the epignosic and forecast problems of the area under consideration.
The Extent Of Destruction Of Landscapes In The Tashkent Region, Shavkat Sharipov, Kamoliddin Khakimov, Davronbek Boymurodov
The Extent Of Destruction Of Landscapes In The Tashkent Region, Shavkat Sharipov, Kamoliddin Khakimov, Davronbek Boymurodov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
The article points to those parts of landscape of the Tashkent region that have become unfit for use in the economy - destroyed lands and their extension as a result of natural and anthropogenic factors.
The Optimal Risk Of Estimator Of Conditional Distribution Function In A Model Of Heteroscedastic Regression With Weakly Dependent Observations, Farkhad Abdikalikov, Laura Reymova
The Optimal Risk Of Estimator Of Conditional Distribution Function In A Model Of Heteroscedastic Regression With Weakly Dependent Observations, Farkhad Abdikalikov, Laura Reymova
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
Paper is devoted to estimation of conditional distribution function in heteroscedastical regression model, in which responses are α-mixing random variables. It is found the expression for mean square deviation of estimator and optimal window width sequence.
Neuro-Fuzzy Identification Of Nonlinear Dependencies, Avazjon Marakhimov, Kabul Khudaybergenov
Neuro-Fuzzy Identification Of Nonlinear Dependencies, Avazjon Marakhimov, Kabul Khudaybergenov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
The paper proposes a fuzzy multilayer perceptron (MLP) and a modified algorithm for its training for solving problems of identification of nonlinear dependencies. The obtained results show a sharp reduction in the search for the optimal parameters of the neuro-fuzzy model compared to classical MLP and increase its accuracy. In the work, questions of optimization of the rule base of the neuro-fuzzy model are also investigated and the temporal and spatial complexity of the proposed algorithm is analyzed. The results of computational experiments show that the number of training epochs has sharply decreased, and productivity has increased compared to the …
Extraction Conductometric Determination Of Scandium And Thorium In Kaolins, Nigora Kutlimurotova, Zulayho Smanova, Habibulla Tojimuhamedov, Zuhra Yaxshiyeva, Jasur Tursunqulov
Extraction Conductometric Determination Of Scandium And Thorium In Kaolins, Nigora Kutlimurotova, Zulayho Smanova, Habibulla Tojimuhamedov, Zuhra Yaxshiyeva, Jasur Tursunqulov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
A method for extraction - conductometric determination of scandium and thorium with tributyl phosphate and trioctyl phosphine oxide in kaolin was developed. The equivalent electrical conductivity of the complex of scandium and thorium with 2,7-dinitrozo-1,8-dihydroxynaphthalene-3,6-disulfonic acid was found. A scheme for the separation and determination of kaolin content is proposed. The isotherms of scandium and thorium extraction are constructed. It was shown that at a concentration of nitric acid of 15.6 M they do not interfere with the determination of thorium and scandium.
Using An A Priori Estimate For Constructing Difference Schemes For Quasi-Linear Hyperbolic Systems, Rakhmatillo Aloev, Mirzoali Khudayberganov
Using An A Priori Estimate For Constructing Difference Schemes For Quasi-Linear Hyperbolic Systems, Rakhmatillo Aloev, Mirzoali Khudayberganov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this paper we consider a class of quasi-linear hyperbolic systems, which allows the construction of a dissipative energy integrals. In the basis of the design and investigation the stability of difference schemes for the numerical solution of the initial boundary value problems for the above class of quasi-linear hyperbolic systems, we put the existence of a discrete analogue of the dissipative energy integrals.
Some Cardinal And Topological Properties Of The $N$-Permutation Degree Of A Topological Spaces And Locally $\Tau$-Density Of Hyperspaces, Farkhod Mukhamadiev
Some Cardinal And Topological Properties Of The $N$-Permutation Degree Of A Topological Spaces And Locally $\Tau$-Density Of Hyperspaces, Farkhod Mukhamadiev
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In the paper we investigate some cardinal and topological properties of the $n$-permutation degree of a topological spaces and locally $\tau$-density of hyperspaces. It is proved that the functors $\exp_n$ and $SP^n$ preserves locally $\tau$-density of any infinite $T_1$-spaces.
Using An A Priori Estimate For Constructing Difference Schemes For Quasi-Linear Hyperbolic Systems, Rakhmatillo Aloev, Mirzoali Khudayberganov
Using An A Priori Estimate For Constructing Difference Schemes For Quasi-Linear Hyperbolic Systems, Rakhmatillo Aloev, Mirzoali Khudayberganov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this paper we consider a class of quasi-linear hyperbolic systems, which allows the construction of a dissipative energy integrals. In the basis of the design and investigation the stability of difference schemes for the numerical solution of the initial boundary value problems for the above class of quasi-linear hyperbolic systems, we put the existence of a discrete analogue of the dissipative energy integrals.
On The Manifolds Of Positive Curvature, Jasurbek Aslonov
On The Manifolds Of Positive Curvature, Jasurbek Aslonov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this paper invariant metrics on Lie group $G=S^3\times R$ are studied and it is found lower and upper bounds for the sectional curvature's of the manifold $G=S^3\times R$.
Positive Fixed Points Of Lyapunov Integral Operators And Gibbs Measures, Farkhod Haydarov
Positive Fixed Points Of Lyapunov Integral Operators And Gibbs Measures, Farkhod Haydarov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this paper it is found fixed points of Lyapunov integral equation and considered the connections between Gibbs measures for four competing interactions of models with uncountable (i.e. $[0,1]$) set of spin values on the Cayley tree of order two.
CarlemanâS Formula For The Matrix Upper Half-Plane, Gulmirza Khudayberganov, Zokirbek Matyakubov
CarlemanâS Formula For The Matrix Upper Half-Plane, Gulmirza Khudayberganov, Zokirbek Matyakubov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this work the Carleman’s formula for the matrix upper half-plane is obtained.
Carleman's Formula For The Matrix Upper Half-Plane, Gulmirza Khudayberganov, Zokirbek Matyakubov
Carleman's Formula For The Matrix Upper Half-Plane, Gulmirza Khudayberganov, Zokirbek Matyakubov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this work the Carleman’s formula for the matrix upper half-plane is obtained.
Using An A Priori Estimate For Constructing Difference Schemes For Quasi-Linear Hyperbolic Systems, Rakhmatillo Aloev, Mirzoali Khudayberganov
Using An A Priori Estimate For Constructing Difference Schemes For Quasi-Linear Hyperbolic Systems, Rakhmatillo Aloev, Mirzoali Khudayberganov
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In this paper we consider a class of quasi-linear hyperbolic systems, which allows the construction of a dissipative energy integrals. In the basis of the design and investigation the stability of difference schemes for the numerical solution of the initial boundary value problems for the above class of quasi-linear hyperbolic systems, we put the existence of a discrete analogue of the dissipative energy integrals.
Some Cardinal And Topological Properties Of The N-Permutation Degree Of A Topological Spaces And Locally Τ-Density Of Hyperspaces, Farkhod Mukhamadiev
Some Cardinal And Topological Properties Of The N-Permutation Degree Of A Topological Spaces And Locally Τ-Density Of Hyperspaces, Farkhod Mukhamadiev
Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences
In the paper we investigate some cardinal and topological properties of the n-permutation degree of a topological spaces and locally τ-density of hyperspaces. It is proved that the functors expn and SPn preserves locally τ-density of any infinite T1-spaces.