Доклады Академии наук Республики Таджикистан, том 62, №11-12, 2019 г.
|Article title and abstract||Pages|
On the mean values of Chebyshev functions
In this article a new estimate for the sums of values of Chebyshev functions for all Dirichlet characters of a given module is obtained.
Key words: Chebyshev function; sum of characters in primes; sieve.
|Shabozov М.Sh., Аbdukarimzoda М.К.|
On the best quadrature formulas for calculation of curvilinear integrals of the first kind
In this article the problem of approximate calculation of the curvilinear integral of the first kind for classes of functions and classes of spatial curves given by continuity modules are studied. The exact error value of the best quadrature formula for all considered classes of functions and curves is obtained.
Key words: curvilinear integral; quadrature formula; error; class of functions; trapezoid formula; nodes.
On the stability of solutions of systems of linear
The article proposes a method of splitting critical variables in the study of the stability of solutions of the system of linear differential equations using the preliminary construction of integral manifolds. The sufficient conditions of applicability of the method of a small parameter when finding splits replacement are provided.
Key words: multipliers; matrix spectrum; integral manifolds; stability of solutions.
On the Noethericity and index of two-dimensional singular integral operators in a limited area
In this note, an effective necessary and sufficient conditions for the of two-dimensional singular integral operators over a bounded domain in Lebesgue spaces with weight and give a formula for calculating the index is established.
Key words: singular integral operation; Noetherian operators; symbol operator; the index of operator.
|Khudoyberdiev Kh.A., Kosimov A.A.|
About recognition of the authors text based on the frequency of syllables
This article considers the model collection of Tajik text, composed by five authors of 12 text. Each work is associated with a digital portrait - the distribution of syllable frequencies. The effectiveness of applying the -classifier for identifying authors of text is established.
Key words: Tajik language; syllable; frequency; recognition of authorship.
|Pavlenko E.P., Rakhimi F.K., Kokhirova G.I., Rakhmatullaeva F.Dzh., Antonyk K.А., Pit N.V., Khamroev U.Kh.|
Two-color photometry of the new asynchronous polar
In this article the two-color photometry of the asynchronous polar IGR J19552+0044 conducted in June 2019 at the International Astronomical Observatory Sanglokh (IAOS) and Crimean Astronomical Observatory (CrAO) during three nights covering 11 spin cycles are present. The strong variation of the spin light curve is detected from cycle-to-cycle on the base of long observational rows. The periodogram analysis revealed the existence simultaneously two periodical processes: the white dwarf spin period of 0.0565 days and the orbital period 0.0580 days. This result is consistent with the assumption that the source of the system radiation is the cyclotron radiation from an accretion column on the white dwarf and the effect of the radiation reflection by the secondary component of later spectral class.
Key words: cataclysmic variables; asynchronous polar; photometry; light curve; spin period; orbital period.
|Ibragimov A.A., Shoyoqubov Sh.Sh.|
Ion formation at bombarding a comet nucleus by protons
of the solar wind
The model of the interaction of the solar wind with the surface of the cometary nucleus at a distance of 3 a.u. is considered, taking into account the data of spacecraft, laboratory experiments and using the method of proportionality of the emission coefficient. The rate of ion formation from surface for both signs is in the sum of the order of 2 × 10 ion m s. It was shown that the bombardment of the surface of the nucleus by particles of the solar wind can contribute to the mechanism of formation of ions in the cometary atmosphere at large heliocentric distances.
Key words: comet's nucleus; solar wind; bombardment; ions; density.
|Salikhov T.Kh., Melikkhudzha N., Mahmalatif A., Khodjakhonov I.T.|
Contribution of substrate absorption to the formation
of the second harmonic of nonlinear photoacoustic response
A theory of the generation of the second harmonic of a nonlinear photoacoustic response has been proposed for the cases when the substrate, along with the sample, is absorbing. The general expression for the complex amplitude of temperature perturbations in the buffer gas is obtained. The case when the sample is thermally thin and transparent is investigated in detail. For this case, expressions are obtained that describe the features of the generated nonlinear PA-signal at the modulation frequency and optical absorption coefficient.
Key words: photoacoustic; thermal nonlinearity; optoacoustic.
|Nizomov J.N., Hojiboev О.A., Hojiboev A.A.|
Interaction of a piecewise-homogeneous structure with an elastic foundation
A numerical solution of the two-dimensional problem of the theory of elasticity in a plane deformation condition is considered. The article presents some results of researches of the stress-strain state of a piecewise-homogeneous body, obtained by numerical modeling based on the boundary equations method.
Key words: boundary equations; numerical modeling; piecewise-homogeneous body; contact problem; dam core; retaining prism.
|Yumaev N.R., Karimov Kh.S., Ahmedov Kh.M.|
Investigation of properties of demonstration thermoelectric generator with compound concentrator
of solar energy
In this paper the design of a solar thermoelectric generator with compound concentrator, consisting of pyramidal and conic concentrators is described. The total concentration coefficient of concentrators is 7. Experimental dependences of the open circuit voltage, short circuit current, and electric power on time are presented. The thermoelectric generator can be used for research and demonstration purposes.
Key words: Seebeck coefficient; thermoelectric generator; composite concentrator; sail of the concentrator.
|Soliev L., Khudoyorbekova Z.P., Nizomov I.M.|
Phase balances of K,Ca//SO,CО,НCО-HO system in 0°C
Phase balances of K,Ca//SO,CО,НCО-HO system 0°C it is established takes part as one of the phases that are in balance system in 0°C in formation of 6 nonvariants points, 18 lines of monovariants and 19 squares of divariants on the basis of the received evidences, it is the first time that the fragment of phase balances diagramed of the studied system is studied.
Key words: system; translation method; phase balances; system; connected diagram; components; nonvariants points; lines of monovariants; squares of divariants.
|Juraev J.Kh., Kurbonov A.S., Nematov A.M., Tagoev M.M., Mirsaidov U.M.|
Processing of borosilicate ore by orthophosphoric acid
In this paper the results of a study on phosphoric acid processing of the initial borosilicate raw materials of the Tajikistan Ak-Arkhar deposit are presents and the optimal conditions of the acid decomposition process have been established.
Key words: borosilicate raw materials; processing; boron-superphosphate fertilizer; phosphoric acid; decomposition; extraction.
|Otaev Sh.D., Mirzoev D.Kh., Jamolov N.M., Kayumov A.M., Mirsaidov U.M.|
Thermodynamic analysis of occuring processes during decomposition of kaolin clays of the Tajikistan Chashma-Sang deposit with phosphoric acid
The article provides an analysis of the thermodynamic characteristics of the processes occurring during the decomposition of kaolin clays of the Chashma-Sang deposit with phosphoric acid. It is shown that the Gibbs energy values of the considered processes involving kaolin clay minerals indicate the occurrence of all possible reactions.
Key words: thermodynamic characteristics; phosphoric acid; Gibbs energy; decomposition; minerals.
|Fayziev F.A., Yatimov S.B., Fayziev A.R.|
Silver mineralization of Kansai ore field (North Tajikistan)
In this article summarizes information about the silver and silver-containing minerals of the Kansai ore field proper. It was previously believed that most silver is associated with galena. Our studies show that in the ore field, the carriers of this metal are mainly silver minerals proper, such as native silver, argentite, hessite, pyrargyrite, proustite, stromeyerite, stefanite, pierceite, polybasite, myargyrite, argentopyrite and kerargyrite. Within the ore field, silver is also present in the form of isomorphic and mechanical impurities in sulfides (galena, sphalerite, pyrite, chalcopyrite) and sulfosalts (tennantite, tetrahedrite).
Key words: native silver; galena; sphalerite; argentite; pierceite; mineral; Kansai; ore field.
|Fayziev A.R., Mukhabatov K.M., Safaraliev N.S.|
Solid micro inclusions in some Pamir self-flowers
In this article the solid microinclusions of minerals in some Pamir gems are described. In colored tourmaline, wolframite, mangancolumbite, zircon, thorite, quartz, fluorite and auerlite, in ruby are plagioclase, spinel, zircon, orthite, calcite and sphalerite, in noble spinel olvin, pyrope, chlorapatite, sapphirin, baddelite and zircon, and in cordierite - zircon.
Key words: microinclusions; colored tourmaline; ruby; spinel; cordierite.
Schrenkia turakulovii Segizbaev (Apiaceae),
a new species from North Tadjikistan
A new species, Schrenkia turakulovii Segizbaev, sp. nova (Apiaceae) from north Tadjikistan is described and illustrated. Notes on affinity and distribution details are provided. The species is endemic to the montes Mogoltavici.
Key words: Middle Asia; North Tajikistan; Mogoltau; species nova.
|Khabirov Z., Нakimzod S.|
The climate impact on the fauna and distribution
of horseflies (Diptera, Tabanidae) in the Hissar valley and
the southern slope of the Hissar range
In this article the data on the distribution and biotopic distributing of horseflies in the Hissar valley and the southern slope of the Hissar range due to the impact of climate change is presents.
Key words: climate; impact; fauna; horseflies; distribution; biotopes; distribution.
|Murodov Sh.S., Sattarov D.S., Karimov H.S.|
Productivity Salvia sclarea in culture in Gissar valley of Tajikistan
In this article the results of studies on the determination of seed productivity and the formation of the green mass of clary sage in a culture (region Rudaki, Gissar Valley) are presents. It was found that in sage nutmeg in the conditions of culture increases the green mass of raw materials and seed productivity. In particular, on the experimental plot, the green mass of raw materials increased by 3, and seed productivity 2.4-2.9 times compared with their natural counterparts. Consequently, further study of the introduction of this plant into the culture on the territory of the Rudaki region and in other regions of the republic has prospects and will contribute to the development of dekhkan farms for the cultivation of essential oilseeds and medicinal plants.
Key words: sage; productivity; seeds; green mass; plot.
|Mukhabbatov D.K., Rasulova S.I., Safolova F.M., Qaraeva A.A.|
Surgical treatment of postpartum perineal rupture
The problem of postpartum insufficiency of the anal sphincter remains an urgent problem of coloproctology and gynecology. The reasons for the unsatisfactory results of sphinctrolevatoroplasty are untimely prevention and late diagnosis of postoperative purulent-inflammatory complications. Developed intraoperative preventive measures and monitoring of the postoperative period improve the immediate results of surgical treatment of postpartum perineal rupture.
Key words: sphincterolevatoroplasty; postpartum rupture of the perineum; postpartum insufficiency of the anal sphincter; purulent-inflammatory complications.