Известия Академии наук Республики Таджикистан. Отделение физико-математических, химических, геологических и технических наук, №4(177), 2019 г.
|Article title and abstract||Pages|
|M.Ilolov , R.Avezov |
On a class of linear functional equations with constant coefficients
An explicit representation of the solution of one class of functional equations with constant coefficients is found.
Ключевые слова: linear functional equation; method of invariants; analytical solution.
Stability of solutions of a linear system of differential equations with impulse actions
This article deals with some sufficient criteria for the stability of solutions of systems of linear differential equations with impulse effects.
Ключевые слова: differential equation; asymptotic stability; systems of impulse; systems of differential equations.
|A.A.Kosimov , R.S.Bahteev |
About identification of the author of the text fragment
Using the model collection of Tajik literary works, we study the problem of the possibility of determining the authorship of a fragment of text of a minimum size extracted from the collection.
Ключевые слова: text; fragment; nearest neighbor; identification.
|G.I.Kokhirova , S.P.Litvinov , U.Kh.Khamroev , M.N.Latipov , A.I.Jonmukhammadi |
The results of fireball observations in Tajikistan
The results of astrometric and photometric reduction of 28 fireballs are presented. From them 11 fireballs were photographed during observations in 2017-2018 and 17 fireballs were registered in 2006-2013. The atmospheric trajectories, velocities, radiants, orbits, brightness and light curves of meteoroids were determined, as well as a belonging to known meteor showers was established.
Ключевые слова: meteor shower; fireball; atmospheric trajectory; radiant; orbit; brightness.
|Ҳ.Ҳ.МӮминов , Sh.F.Muhamedova |
On the breathers of the scalar nonlinear Shrödinger equation
By use of numerical simulation methods, the evolution of the multisoliton solution of the scalar nonlinear Schrödinger equation with vanishing boundary conditions is analyzed. The formation of a stable two-soliton solution is observed, which demonstrates breather dynamics at a non-zero velocity of motion.
Ключевые слова: breather; scalar nonlinear Schrödinger equation; vanishing boundary conditions.
|Sh.Kh.Khalifaeva , V.A.Maslov , B.I.Nazarov , F.Rahimi , S.F.Abdullaev |
Heavy metals in the composition of the atmospheric aerosol of the south-central part of Tajikistan
The content of heavy metals in the composition of atmospheric aerosol in the south-central part of Tajikistan is considered and statistics on the content of heavy metals in dust aerosol samples are presented. The interannual variation in the contents of As, Pb, and Zn in the composition of atmospheric aerosol is presented; a map of the places of sampling and back trajectories for the heavy metals are created.
Ключевые слова: atmospheric aerosol; heavy metals; back trajectory.
|M.N.Rakhmatov , V.A.Maslov , S.F.Abdullaev , U.Madvaliev |
Geochemical evaluation of heavy metal concentration in soil samples in the Sogdian region
Based on experimental data, the geochemical index (I) of pollution of soils in northern Tajikistan was determined. This made it possible to assess the degree of soil contamination with heavy metals. An environmental interpretation of the geochemical pollution index showed that the soil in the territory of the Degmay tailing dump is heavily contaminated with especially hazardous metals: lead (I= 3.28, highly polluted). For arsenic (I = 3) and zinc (I = 4.34, extremely heavily contaminated). Spitamen region is characterized by a high level of arsenic pollution (I= 3.77, a class of very unfavorable conditions). The remaining HM soil is moderately contaminated (1
Ключевые слова: geochemical pollution index; heavy metals; zinc; lead; arsenic; especially dangerous elements; Sogd region.
|D.O.Davlatov , Sh.B.Nazarov , A.S.Kurbonov , U.M.Mirsaidov |
Investigation of water treatment of the sinter by joint processing of boron- and alumosilicate ore with sodium sulphate
In this article presents the results of a study of the water treatment of a sinter during the joint processing of the daburite raw material of the Ak-Arkhar deposit and nephelinesyenites of Turpy deposit with sodium sulfate. The influence of various physicochemical factors on the process of dissecting water-soluble constituents of the sinter has been studied. The optimal conditions for conducting water treatment of the sinter are established, which ensure the maximum extraction of components into the solution.
Ключевые слова: water treatment; sinter; boron-silicate ore; nephelinesyenite; sodium sulfate; processing.
|J.Kh.Juraev , A.S.Kurbonov , M.M.Tagoev , A.M.Nematov , M.Majidov , U.M.Mirsaidov |
Physical and chemical bases of sintered Tajikistan
Ak-Arkhar deposit borosilicate ore processing with orthophosphoric acid
The results of orthophosphoric acid decomposition of borosilicate ore concentrate of the Tajikistan Ak-Arkhar deposit are presented and the optimal parameters of ore processing have been found.
Ключевые слова: borosilicate feedstock; processing; borophosphoric fertilizer; phosphoric acid; decomposition; extraction.
|P.R.Ibrohimov , I.N.Ganiev , F.A.Rahimov , Z.R.Obidov |
Anode behaviour of Zn0.5Al alloy, doped with molybdenum,
in the sour environment
In paper results potentiodynamical researches of anode behaviour of Zn0.5Al alloy, doped with molybdenum, in the sour environment are presented. It is shown, that doped zinc-aluminium alloy molybdenum promotes reduction of corrosion rate of an alloy initial at 1.5-2 times.
Ключевые слова: Zn0.5Al alloy; molybdenum; potentiostatically method; HCl electrolyte; corrosion potential; corrosion rate.
|H.К.Маkhкамов , S.Khаliкоvа , D.Kh.Khаliкоv , М.I.Ilоlоv , H.М.Аkhмеdоv |
About the prospect of using Jerusalem artichoke as
a vegetable raw material for producing pectin
A comparative study of the hydrolysis extraction of pectin polysaccharides of Jerusalem artichoketubers (TNB) of the Sarvat cultivar without (BEI) and after extraction (PEI) of inulin was carried out. Products of hydrolysis were divided into fractions: microgel (MG), the pectin aceous substances (PS) and oligosaccharides (OS) according earlier developed methods. Low yields of the main fractions of pectin polysaccharides - microgel and pectin substances (MG and PV), with a high content of oligosaccharides (OS) were shown. An increase in the yields of MG and PV under the conditions of BEI was established compared to PEI. The low yield of general fractions(MG and PC), small among in residues the galacturonic acid (GA) at high degree of their metossilazionethat allows to conclude regardinglow perspective of using of TNB as a vegetable source for receiving pectin aceous polysaccharides.
Ключевые слова: Jerusalem artichoke; pectin substances; microgel; hydrolysis-extraction; oligosaccharides.
|Sh.D.Otaev , D.Kh.Mirzoev , A.M.Kayumov , U.M.Mirsaidov |
Thermodynamic evaluation of the Tajikistan Chashma-Sang deposit kaolin clays decomposition with mineral acids
The results of thermodynamic study of the decomposition of kaolin clay minerals of the Tajikistan Chashma-Sang deposit at various temperature ranges during sulfuric and nitric acids decomposition are presented. Gibbs energy changes depending on temperature and the processes occurrence probability during the interaction of kaolin clay minerals with the indicated acids are shown.
Ключевые слова: kaolin clay; thermodynamic evaluation; sulfuric acid; nitric acid; Gibbs energy.
|M.M.Mamadvafoev , D.A.Davlatshoev |
About the distribution functions of apatite and
other auxiliary and petrogenic minerals of intrusive rocks of Kafandara ore field (Eastern Hissar)
Probabilistic-statistical methods have determined the functions (rules) of the distribution of apatite and other 12 auxiliary and petrogenic minerals in 9 types of rocks of 3 intrusive complexes, as well as in their general population. It was established that out of 114 cases, in 75 of them (66%), the empirical distribution of mineral contents in the rocks does not contradict the hypothetical normal function, and in 39 (34%) they deviate from it, being consistent mainly with the log-normal (log-normal) function. In 5 cases, the empirical distribution is not consistent with either a hypothetical normal or lognormal function. It is concluded that the hypothetical lognormal distribution function is not a universal empirical distribution function of auxiliary and petrogenic minerals in igneous rocks of the ore field.
Ключевые слова: Eastern Hissar; Kafandara ore field; intrusive rocks; distribution functions; apatite grade; auxiliary and petrogenic minerals.
|F.A.Fayziev , S.B.Yatimov , A.R.Fayziev |
Silver mineralization of Kansai ore field (North Tajikistan)
The 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).
Ключевые слова: native silver; galena; sphalerite; argentite; pierceite; mineral; Kоnsоi; ore field.
|J.N.Nizomov , A.A.Hojiboev , О.A.Hojiboev |
Study of voltage distribution in a multi-connected area
by the method of boundary equations
The article considers the solution of the plane-deformed elasticity theory problem as applied to underground structures. The effect of two mutually closely spaced holes on the stress-strain state of the latter is investigated. Boundary integral equations for an external problem are compiled. The developed algorithm, mathematical model, and calculation programs based on the boundary element method are implemented using the underground structures of the Rogun HPP as an example.
Ключевые слова: a multiply connected area; cavity; boundary integral equation; infinity; normal; stress; displacement; underground structures; mutual influence.
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