Известия Академии наук Республики Таджикистан. Отделение физико-математических, химических, геологических и технических наук, №4, 2013 г. |
File | Article title and abstract | Pages |
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Скачать | Rakhmonov Z.Kh. | 7-22 | Estimation of short character sums |
Nontrivial estimate was obtained for sums of values of primitive character modulo on the sequence of shifted numbers , , for and . |
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Ключевые слова: нетривиальная оценка; характер Дирихле; сдвинутые простые числа; короткая сумма характеров; Nontrivial estimate; Dirichlet character; Shifted primes; short character sums. | |
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Скачать | Shabozov M.Sh., Oliftaev N.F. | 23-32 | The best approximation and an exact values of widths for some classes periodic functions in
space |
For the -modulus of continuity of -th order, formulated by K.G.Ivanov was solved the problem of calculation the exact values of constant in the inequalities of Jackson-Stechkin type in space. The exact values of -widths for the class of functions which are given by averaged positive weights with the values of -modulus of continuity of the -order derivatives, satisfying a certain restrictions are calculated |
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Ключевые слова: наилучшее полиномиальное приближение; точные константы; неравенства типа Джексона-Стечкина; τ-модуль гладкости; аппроксимационная характеристика; n-поперечник; best polynomial approximations; exact constant; Jackson’s inequality type; τ-modulus of continuity; approximative characteristic; n-widths. | |
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Скачать | Tukhliev K. | 33-46 | Upper bounds of the deviations of certain classes of functions from their partial sums of Fourier-Chebyshev in
space. I |
The exact estimates of the rate of convergence of the Fourier-Chebyshev on some classes of functions defined by a differential operator of the second order and characterized by generalized modulus of continuity of the th order in the space are given. The upper bounds of deviations given classes of functions from their partial sums of Fourier-Chebyshev in space are calculated. The exact values of the -widths of classes of functions defined by the averaged modulus of continuity th order are found. |
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Ключевые слова: оператор обобщённого сдвига; модуль непрерывности m-го порядка; верхние грани; ряд Фурье-Чебышёва; дифференциальный оператор; generalized shift operator; modulus of continuity of m-order; upper bounds; Fourier-Chebyshev series; differentiation operator. | |
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Скачать | Faraydunov O.Q. | 47-56 | Error estimation of quadrature formula Hermite-Chebyshev |
Asymptotically exact estimates for the remainder of the quadrature formula for Hermite-Chebyshev definite integrals on the interval with weight on nodes at the zeros of Chebyshev polynomials of the first kind on some classes of functions defined by the moduli of continuity of th order, characterized by generalized shift operator. |
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Ключевые слова: квадратурная формула; модуль непрерывности; погрешность; дифференциальный оператор; quadrature formula; modulus of continuity; error; differentiation operator. | |
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Скачать | Ismati M. | 57-68 | Аbout classical and generalized solutions of problem type Coushi for operator Dalamber of arbitrary degrec |
In the present paper in n- dimensional Euclidian space established of correct solvability problem type Coushi for operator Dalamber of degrees for classical and generalized solutions. |
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Ключевые слова: задача Коши; задача типа Коши; оператор Даламбера; разрешимость; корректная разрешимость; Problem of Coushi; problem type of Coushi; operator Dalamber; solvability; сorrect solvability; classical and generalized solutions. | |
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Скачать | Usmanov Z.D., Dovudov G.M. | 69-76 | Algorithm for representing a specific tajik word form as a phrase piece |
The subjects of our discussion are Tajik word forms not related to any of the parts of speech. We offer an algorithm for constructing a piece of phrase, equivalent in meaning to the given word form. |
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Ключевые слова: таджикский язык; словоформа; постфикс; словосочетание; алгоритм; автоматизаци; Tajik language; word form; postfix; phrase; algorithm; automation. | |
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Скачать | Vasilenko T.A., Kirillov A.K., Doroshkevych A.S., Shylo A.V. | 77-85 | Effects of low frequency pulsed magnetic field on the electrical characteristics of coal |
By the electrochemical impedance method a coal with early stage of metamorphism was investigated. The dependencies from the frequency of relative permittivity, conductivity and loss tangent for the starting, wetted, and dried sample was presented. It is shown that the effects of pulsed magnetic (PMF) field with intensity H = 10
÷ 10
A/m and a frequency pulse repetition ν = 1 Hz is results to significant changes of these variables. The samples had different responses to the PMF with depending from the humidity. Using the equivalent electrical circuit, the characteristic relaxation times of the magnetically induced polarization of fluid molecules and the solid matrix of coal was determinates. The largest changes was occurs at the interfaces of the sample. At long relaxation processes the return of all electrical characteristics to the original state is not observed and their changes in the relaxation process have an alternating pattern. The work shows the potential for effective degassing of coal seams using PMF. |
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Ключевые слова: каменный уголь; электрические свойства; слабые импульсные магнитные поля; магнитоиндуцированные эффекты; дегазация каменноугольных пластов; anthracite coal; electric properties; weak pulsed magnetic fields; magnetic fields inducted effects; degassing of coal layers. | |
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Скачать | Nasriddinov S.K., Sharipov D.Sh., Islomova M.S., Badalov A. | 86-92 | Synthesis and thermodynamic characteristics of fluoridetetrahydrate cobalt (II) and hidroksokarbonate |
Fluoride tetrahydrate cobalt (II) was obtained by the reaction of cobalt hidroksokarbonat (II) with hydrofluoric acid solutions of different concentrations. The enthalpy of this and adverse reactions was defined by calorimetry method. By thermochemical cycles was determined the enthalpy of formation of fluoride tetrahydrate cobalt (II) and gidroksokarbonata cobalt (II). |
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Ключевые слова: кристаллогидрат; гидрофторид; гидроксокарбонат-кобальт-калориметрия; растворение; энтальпия образования; crystalline; hydrofluoride; cobalt; calorimetry; dissolution; the enthalpy of formation. | |
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Скачать | Rakhimov Kh.A., Abulkhaev V.D., Ganiev I.N., Ubaydov S.O. | 93-97 | State diagram of the Gd
Bi
- Lu
Bi
system |
DTA, XRD and metallography data were used to map out the Gd
Bi
- Lu
Bi
phase diagram. The results of resistivity and thermoelectric power measurements are consistent with phase diagram data. Crystallochemical investigations have shown, that solid solutions Gd
Lu
Bi
(х= 0.5-4.5) of the Gd
Bi
- Lu
Bi
system crystallizes in rhombic Y
Bi
structural type. |
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Ключевые слова: диаграмма состояния; синтез; сплавы; твердые растворы; удельное электросопротивление; термо-э.д.с; микротвёрдость; state diagram; synthesis; alloys; solid solutions; resistivity; thermoelectric power; microhardnes. | |
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Скачать | Bobonazarov M., Rakhimova M.M., Mirzoev B. | 98-105 | Sedimentation analysis of phosphorite of the Karatag deposit of the Republic of Tajikistan |
We use the method of Sieve weight and sedimentation analysis identified pre-ground particulate characteristics ( size up to 2 mm) granular phosphorite of the Karatag deposits. The sizes of particulate fractions and their weight identified. Using analytical methods Cjurupy calculated minimum and maximum sizes of deposited particles , the kinetics of the deposition process , calculated olydispersity parameter . Calculated speed and the deposition of particulate matter of phosphorite in the vertical reactor. |
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Ключевые слова: фосфорит-ситовый анализ; седиментационный анализ; аналитический метод Цюрупы; свободное и стеснённое осаждение; phosphorite; sieve and sedimentation analyzes; analytical method Cjurupy; free and crowded precipitation particles. | |
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Скачать | Sharifov A., Akramov A.A., Nazirov Y.G., Muminov A.K. | 106-112 | Strength and deformability of concrete with the abdition alkaline extract of cotton stalks |
The paper summarizes the results of the chemical additive of alkaline extract of cotton stalks on the properties of concrete and concrete and characterized the mechanisms of their influence on the process of hydration and hardening of cement. |
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Ключевые слова: щелочной экстракт; гидратация; цемент; бетон; прочность; подвижность; жесткость; alkaline extract; hydration; cement; concrete; strength; mobility; rigidity. | |
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Скачать | Sabirov A.A. | 113-121 | The foraminiferal scale of devonian system of Tajikistan |
For the first time design foraminiferal scale of Devonian system of Tajikistan, including 17 foraminiferal zones. They compare with conodontal and brachiopodal zones. |
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Ключевые слова: фораминиферы; девон; стратиграфия; foraminifers; Devonian; stratigraphy. | |
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Скачать | Fayziev A.R., Nabiev N.F., Buryak A.V. | 122-130 | Sulfides Pakrut gold deposit (Central Tajikistan) |
The article describes the sulphides deposits Pakrut. Some of them (pyrite, arsenopyrite) gold concentrates are important. |
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Ключевые слова: месторождение; сульфиды; минералы; элементы; метасоматиты; deposit; sulfide; mineral; element; metasomatic. | |
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Скачать | Akhmedov Kh.M., Karimov Kh.S., Safaraliev N.M., Markaev A.G., Obidov F.U., Ismoilov R.A., Akhmedov F., Kabutov Z.Q. | 131-137 | Double contour solar water heater on the base of primary aluminum |
It is described double contour solar water heater on the base of primary aluminum fabricated in Academy of Sciences. The results of investigation of the properties of the heater in natural conditions during a year are presented. It was found that the average maximum temperature of water was equal to 56.8°C. Efficiency of the water heater was equal to: at winter - 32%, spring and autumn - 41%, summer - 53%. The volume of reservoir of the water heater was equal to 50 liters. |
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Ключевые слова: солнечный водонагреватель; коллектор; резервуар; энергоэффективность; температура воды и окружающей среды; solar water heater; collector; basin; energy efficiency; water temperature and environment. | |
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Скачать | | 138-143 | |
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Ключевые слова: . | |
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Скачать | | 144-145 | |
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Ключевые слова: . | |
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