Известия Национальной академии наук Таджикистана. Отделение физико-математических, химических, геологических и технических наук, №4(185), 2021 г.
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On one algebra of two-dimensional integral operators with an odd characteristic with a shift
The paper studies the algebra of two-dimensional singular integral operators with odd characteristic with shift, new classes of polykernels of Bergman operators in Lebegа space. Necessary and sufficient conditions are found for the above operators to be noetherian, and a formula is obtained for calculating the index.
Ключевые слова: polykern-function; polykern-Bergman operator; singular integral; operator symbol; operator index; operators noetherian.
Solvability of the pursuit problem for a linear differential game of a neutral type with integral restrictions
In a Hilbert space, we consider the pursuit problem for a linear differential game of neutral type with integral constraints on the players' controls. Two theorems on the solvability of the pursuit problem are proved.
Ключевые слова: pursuit problem; differential game of neutral type; Hilbert space; integral constraints; pursuit time.
Critical phenomena near the smectic-isotropic liquid phase transition
In this paper, we consider the influence of the smectic A phase transition on the pre-transition phenomena in the isotropic phase of a nematic liquid crystal. It is shown that as the width of the nematic zone decreases, the regular part of the heat capacity increases, which leads to deviations from the Curie - Weiss law for the susceptibility from the root divergence from the heat capacity.
Ключевые слова: phase transition; nematic zone; isotropic liquid; smectic phase; order parameter.
Catalysis and synthesis of catalyst
In this article summarizes the basic aspects of catalysis. The synthesis of nano-heterogeneous zeolites - catalysts are considered. Synthesis of catalysts based on the impregnation method of the carrier with metal salts with the formation of a «crust» layer along the grain is shown. Sol-gel method used for formation binary Mg-Si catalyst are considered.
Ключевые слова: catalysis; nano-catalysts; heterogeneous catalysis; sol-gel method.
|A.S.Kurbonov , M.M.Tagoev , Sh.D.Otaev , A.Р.Tagаev , A.М.Kayumov , U.M.Mirsaidov |
Comparative assessment and characteristics of the sintering process of boron and aluminosilicate ore with sodium and calcium chloride
The results of a comparative assessment and characteristics of the sintering process of borosilicate ores and kaolin clays with chlorine-containing reagents are presented in the article. The optimal parameters of sintering of boric ore of the Ak-Arkhar deposit with sodium and calcium chlorides and sintering ofkaolin clays of the Chashma-Sang deposit with CaClwith subsequent hydrochloric acid treatment of the sinter have been found.
Comparative assessments of the process of sintering boron and alumosilicate ores with sodium and calcium chlorides are given as well.
Ключевые слова: sodium chloride; calcium chloride; boric ore; kaolin clay; optimal parameters; comparative assessment.
|B.I.Asrorov , S.B.Bahriddinzoda , T.Nasimov , Z.H.Gaibullaeva |
The catalytic process of obtaining hydride aluminum from hydrogen from coal gasification
The article discusses the heterogeneous catalytic process of obtaining hydride aluminum hydrogen from coal gasification.
A palladium mobile was used as a catalyst for the preparation of aluminum hydride. Research used hydrogen obtained by coal gasification method. The work was used to be a sample of coal of the background-Yagnobskoye field (Tajikistan) of the following composition, masses. %: Humidity - 4.0; volatile components - 0.98 %; resin - 4.5 %; C - 81.0; H - 5.2; N - 1.0; O - 2.0; S - 1,4; ash - 5.3. The results obtained suggest that when processing aluminum chloride in the presence of a palladium catalyst atoms of hydrogen in the gas discharge stream, a rhombic modification of aluminum hydride with grid parameters are formed: а=0.534±0.005 нм; в=0.744±0.005 нм; с=0.575±0.005 нм.
Ключевые слова: catalyst; palladium; hydride aluminum; hydrogen; restoration; water gas; gasification.
|Sh.R.Samikhov , F.M.Toshov , Sh.A.Kurbanov , M.S.Ismoilova , S.Sh.Safarov |
Mechanism and kinetics of decomposition of phosphorite minerals with hydrochloric acid solutions
The results of studies on hydrochloric acid decomposition of phosphorus-containing concentrates of Rivat deposit are presented. The kinetic parameters of this process are defined.
Ключевые слова: concentrate; deposit; hydrochloric acid decomposition; process temperature; decomposition duration; extraction degree.
|A.Badalov , F.A.Khamidov , D.T.Isozoda , D.N.Eshov , U.M.Mirsaidov |
Modeling of change regularity of thermodynamic
properties of lanthanide borohydrides
Thermodynamic characteristics of all line borohydrides have been clarified and/or determined by means of semiemperical method. The system analysis has been carried out and it has been determined that regularities of their changes depending on nature of lanthanides has complicated character with revealing of tetrad-effect. The mathematical models of determined regularities for the borohydrides of cerium and yttrium subgroups have been composed.
Ключевые слова: lanthanide borohydrides; thermodynamic characteristics; system analysis; changes regularities; mathematic modeling.
|U.R.Jobirov , I.N.Ganiev , M.Ch.Shirinov , Z.R.Obidov |
Oxidation of Zn0.5Al zinc alloy, doped with erbium,
in the firm condition
The thermo gravimetrical method investigates interaction of Zn0.5Al zinc alloy, doped with erbium, with air oxygen in an interval to temperature 523 - 623K in the firm condition. Kinetic parameters of process of high-temperature oxidation of alloys are defined. Showed, that additives of erbium within 0.01÷1.0 wt.% slightly increase oxidability of an zinc alloy, and products of oxidation of alloys are oxides ZnO, AlO, AlO∙ZnO, ErO.
Ключевые слова: Zn0.5Al alloy; erbium; thermo gravimetrical method; high-temperature oxidation; speed of oxidation; energy of activation.
Processing of boron and aluminosilicate ore of Tajikistan
The article presents the results of the laboratory of complex processing of mineral raw materials and wastes of the V.I.Nikitin Institute of Chemistry of the National Academy of Sciences of Tajikistan in the field of processing boron and aluminosilicate ores. Acidic, chlorine and sintering processing methods have been found for boron raw materials. Basic technological schemes for processing raw materials with the production of boric acid, enamel, BCl and other useful components have been developed.
Processing methods have been found for aluminosilicate raw materials as well, optimal processing parameters have been determined and technological schemes for obtaining valuable products have been developed.
Ключевые слова: processing; borosilicate ore; aluminosilicate ore; technological scheme; optimal parameters.
Co-processing of waste slurry field aluminum production with nepheline syenite of the Turpi deposit
This article presents the results of joint sintering waste from the Talko sludge field and nepheline Turpi and the optimal sitering modest: t=900-950C, the ratio of nepheline syenite and waste =1:2, the sintering duration 40-60 mines, The solid residue was also decomposed with sulfuric acid after water treat ment of the sinter to obtain useful components for the production of aluminum.
Ключевые слова: washed sludge; Industrial waste; water-insoluble part; sinter; sulfuric acid decomposition.
|M.M.Mamadvafoev , D.A.Davlatshoev |
Sulfur in the intrusive complexes of the Kafandara ore field (Central Tajikistan)
The article is the first to consider the distribution function of sulfur, its abundance and correlation with iron in 34 petrochemical different types, geologically different in age and tectonically different modes of intrusive rocks of the Southern Tien Shan in the position of the Kafandara ore field in Central Tajikistan.
Ключевые слова: sulfur; distribution function; abundance in rocks; correlation with iron; Kafandara ore field.
|A.K.Khodzhiev , J.H.Aminov |
To geochemistry and geodynamic position of the Khojamafrach plagiogranitoid intrusive of the South Gissar zone, South Tien-Shan
In this article the geochemical features of the Khojamafraj pluton are analyzed and for the first time interpreted in the context of the tectonic plates theory. The analysis of the geochemical features of the rocks suggests that the intrusive rocks of the Khojamafrach pluton formed in an islans arc geodynamic conditions.
Ключевые слова: South Gissar; Khojamafrach intrusion; geochemistry; gabbro-plagiogranitoids; geodynamics.
|Kh.S.Karimov , M.Tariq Chani , Batool Haider , A.C.Kodirov , J.Sh.Rahmatov , Kh.M.Akhmedov |
Electric properties of the flexible sensor based on carbon nano tube and orange dye composite
The article investigates the electrical properties of a flexible sensor based on a carbon nanotube and a composite with an orange dye obtained by rubbing in. It was shown that under the action of pressure up to 73.25 gs/cm, the initial resistance and impedance of the sensors at 200 kHz decreased three times (contact resistance) and five times (volume resistance). An increase in temperature from 30 to 86°C leads to a decrease in the resistance and impedance of the sensors. It was found that an increase in humidity from 50 to 91% leads to a decrease in the resistance and impedance of the sensors from 1.08 to 1.43 times. The research results can be used to lower the physical properties of a composite based on CNTs and organic semiconductors, in particular, an orange dye in electronic devices.
Ключевые слова: carbon nanotubes; orange dye composite; resistance; impedance; pressure; temperature; humidity; sensor; composite; temperature coefficient of resistance.
|J.N.Nizomov , I.K.Kalandarbekov , I.I.Kalandarbekov |
On the calculation methods of loading systems of multi-storey buildings based on discrete models
The improvement of calculation methods is one of the main tasks of structural mechanics. A comparative analysis of numerical methods for calculating the load-bearing structures of buildings is presented. The results of a comparative analysis of the methods of concentrated deformations and finite elements are presented.
Ключевые слова: constructive scheme; lumped deformation method; finite element method; discrete model; stress-strain state; stiffness matrix; compression-tension; compliance of real bonds; stiffness characteristic.
Ключевые слова: .