- Hits: 52
UDC:534.16: 535.341
FEATURES OF EXCITATION OF LINEAR AND NONLINEAR THERMAL WAVES IN DIELECTRIC FILMS ON A SUBSTRATE UNDER IRRADIATION WITH A HARMONICALLY MODULATED ION BEAM
Salikhov T.Kh., Abdurahmonov A.A.
Research Institute of the Tajik National University
In [1] we considered the features of the generation of linear and nonlinear thermal waves in free dielectric films in air under the action of a harmonically modulated ion beam with a frequency of [2-6]. However, the case when the film is attached to a substrate was not considered. The purpose of this work is to generalize the results of [1] taking into account the presence of a substrate.
- Hits: 41
UDC: 541. 123.6
SOLUBILITY AND PHASE EQUILIBRIUM OF AN WATER SYSTEM - POTASSIUM, MAGNESIUM, CALCIUM SALTS CARBONATES AT A TEMPERATURE OF 25°C
(K+,Mg2+,Ca2+//CO32--H2O)
Umaralii S., Usmonov M.B.
Tajik State Pedagogical University named after S. Ayni
Multicomponent water-salt systems are the composition of many natural and technical objects that are the subject of research in the field of chemistry, mineralogy and technology. The main method for studying chemical systems is physicochemical analysis, which can be used to determine the laws of interaction of their components and construct their state or solubility diagrams. State diagrams of chemical systems are an expression of the relationship between the properties of substances (melting, solubility, etc.) and the influence of external factors (temperature, pressure, etc.) [1]. The founder of this discipline, N.S. Kurnakova, played a great role in developing the theory of the foundations of physicochemical analysis [2]. N.S.
- Hits: 40
UDC:54.057.12
SYNTHESIS OF 2-R-AMINO-5,6-ETHYLENE-1,4-DIOXYBENZTHIAZOLANE FROM 6-AMINO-1,4-BENZODIOXANE
Turdialiev M.Z., Pulatov E.Kh.
Institute of Chemistry named after V.I. Nikitin NAS of Tajikistan,
Dushanbe, st. Ayni, 299/This email address is being protected from spambots. You need JavaScript enabled to view it.
It is known that benzo-1,4-dioxane is obtained by the interaction of pyrocatechol with dibromoethane [1] and some of its derivatives are used as medicinal preparations, for example, fluparoxan, domoxin, eltoprazine, imiloxan, piperoxan, proraxan, prosimpal, butyroxan and a number of other preparations with a wide range of biological activity [2-4].
- Hits: 41
UDC:547.426.251+547.426.21
MODIFICATION OF DIGLYCEROL WITH ACETALS, DI-KETALS AND POLYOLS
Sharipov F.N., Ikromov M.S., Rajabzoda S.I.
Scientific and Research Institute of the National University of Tajikistan
Linear acetals, mostly obtained on the basis of vinyl or orthoethers, are present in most organic substances and are widely used as semi-products [1-5]. The method of obtaining linear acetal is obtained by condensation of choriataldehyde and triethyl orthoformate (reaction scheme 1) in the presence of PTSA catalyst at T=70 °C for 6 hours. The yield of the reaction product is 82% [6-10].
- Hits: 44
UDC:546.3.12
INFLUENCE OF TYPES OF CHEMICAL BANDS ON THE STRUCTURE AND PHYSICAL-CHEMICAL PROPERTIES OF METALS AND SEMICONDUCTORS AFTER MELTING.
1Nurov Q.B.., 2Juraev T.J., 3Rustami T.
1 Tajik State Pedagogical University named after S. Ayni
2 Tajik Technical University named after M.S. Osimi
3 Bokhtar State University named after N.Khusrav
Introduction. The type of bonds formed between the elementary particles in the crystal is determined by the electronic structure of the interacting atoms. The elementary particles in the crystal are close to a certain distance, which gives the crystal thermodynamic stability. The distance of particles approaching each other is determined by the interaction of the forces acting on the crystal. Gravitational forces arise as a result of the interaction of electrons with the positively charged nuclei of their own atoms, as well as with the positively charged nuclei of neighboring atoms. Repulsive forces are caused by the interaction of the positively charged nuclei of neighboring atoms when they are brought close together.
- Hits: 40
UDK:629.4.016./66.01.02. 08./ 661.862.666.32
TECHNICAL AND ECONOMIC ASSESSMENTS OF THE TECHNOLOGY OF PRODUCTION OF UNPURIFIED AND PURIFIED COAGULANT FROM KAOLIN CLAYS OF THE DEPOSIT « CHASHMA-SANG »
* Naimov N.A., ** Rajabzoda N.Kh., *** Mirsaidov U.M.
*Research Institute of the Tajik National University
**JSC "Tajik Aluminum Company"
** *Chemical, Biological, Radiation and Nuclear Weapons Agency
security of the National Academy of Sciences of Tajikistan
It is obvious that the progress and development of technology and engineering definitely require an improvement in the quality of life, one of the aspects of which is the improvement of the supply of clean drinking water. However, the provision of high-quality drinking water is becoming increasingly difficult and thus there is a need to increase the capacity of water treatment systems using various coagulants and flocculants [1,2].
- Hits: 56
UDC:541.123.2
THE TEMPERATURE INFLUENCE ON THE IONIZATION CONSTANTS OF α- AND β-ALANINE IN AQUEOUS SOLUTIONS
Hakimov J. N.*, Rahimova M.M., Samadov A.S., Faizullozoda E.F.
Tajik National University
Introduction. Amino acids, the foundational components of peptides and proteins, serve as indispensable chemical entities within the organism, essential for the harmonious conduct of metabolic processes and overall well-being. The scarcity of amino acids due to inadequate dietary intake or suboptimal endogenous synthesis may manifest in deficiency symptoms, including pronounced weight loss and compromised immune system function. Given the transient nature of amino acid storage within the body, maintaining a healthy lifestyle necessitates fulfilling the daily amino acid requirements either through nutritional intake or supplementation [1]. The presence of amino (–NH2) and carboxyl (–COOH) functional groups endows amino
- Hits: 48
UDK: 546.722, 546.723, 546.185-325
IR SPECTROSCOPY OF SURFACE PHOSPHATE COMPLEXES ON (HYDRO) OXIDE PHASES OF IRON (REVIEW).
1,2Kuzin A.V., 3Samadov A.S., 4Shelontsev V.A., 1Eliseeva E.A.,
5Gerasimova I.V.
1Moscow State Technical University named after Bauman. 2Moscow State. Pedagogical University.3Tajik National University. 4Omsk Humanitarian Academy. 5Omsk State Pedagogical University
Iron and aluminum oxyhydroxides can have a significant impact on the processes of formation, distribution, distribution of environmental pollutants, nutrients and various other substances dissolved in water, water systems and "mineral surfaces of the soil" through adsorption and co-adsorption processes and, thus, control the geochemical cycles of many elements.
- Hits: 54
UDC:547.546
SYNTHESIS OF 3-R-1,5-DINITRO-3-AZABICYCLO[3.3.1]NON-7-EN-6-IMINES BASED ON 2,4-DINITROANILINE
Mukhtorov L. G.1, Aleksandrov N. S. 1, Simonov R.V. 2, Belocon D. A.4, Ivanova E.V. 4, Atroshchenko Y. M. 2, Karimov M. B.3, Shakhkeldyan I. V.4
1Youth research laboratory for the synthesis of organosilicon monomers and functional polymers, Tula State Pedagogical University L.N. Tolstoy,
2Center for technological excellence "Advanced chemical and biotechnologies" of Tula State Lev Tolstoy Pedagogical University,
3Branch of the National Research Technological University “MISiS”,
4Department of Chemistry. Tula State Pedagogical University by Leo Tolstoy.
Introduction. Obtaining new derivatives of 3-azabicyclononane is an important direction in the synthesis of organic compounds. It is known that 3-azabicyclononane is a key pharmacophore of a few plant alkaloids that are widely used in medicine. Among the synthetic heterocycles containing the 3-azabicyclo[3.3.1]nonane fragment, compounds with various types of biological activity were found: analgesic, anti-inflammatory, antimicrobial, fungicidal, anticancer, antioxidant, etc.
- Hits: 40
UDC: 551.521.3, 551.583
SPATIO-TEMPORAL VARIATION OF THE ELEMENTAL COMPOSITION OF ATMOSPHERIC AEROSOL IN TAJIKISTAN
Abdullaev S.F., Azizova Sh.M., Abdulloeva S. J., Kholmurodov M.
Institute of Physics and Technology named after. S.U. Umarov
Introduction. According to the standards of the World Health Organization ( WHO ), almost 90% of the world's population lives in places with hazardous air quality. A database collected in 91 countries at 1,600 stations shows that only 12% of the world's population lives in countries that meet the WHO air quality standard [ 1-12]. One of the best indicators of air quality is the content of aerosol atmospheric particles in the atmosphere smaller than 10 micrometers in size and designated as
- Hits: 42
UDC:551.521.3,551.583
CONTENT OF RARE EARTH ELEMENTS IN SOILS OF THE SOUTH-EASTERN PART OF THE SUGHD REGION
1Rahmatov M.N., 2Abdullozoda S.F., Ismoilov K.A.,
1State Educational Institution “Khujand State University named after Academician Bobojon Gafurov”
2Physical and Technical Institute named after S.U. Umarov
Despite the fact that in recent years many review papers have been published devoted to the study of the geochemical behavior of rare earth elements (REE) in soils and plants [1, p. 75; 2, p. 57; 3, pp. 101-107], their concentrations in water and precipitation [4, p. 648; 5, pp. 125-131], it should be noted that there is an almost complete absence of general works on the geochemical cycle of REE in the lithosphere-atmosphere system.
- Hits: 45
UDC:581:53
INFLUENCE OF TREATMENT OF CORN SEEDS OF THE "DILSHOD" VARIETY WITH A BARRIER DISCHARGE ON THEIR GERMINATION, PLANT GROWTH AND PRODUCTIVITY
Nazirov F.M, Khojazoda T.A.
Tajik National University
Introduction. Barrier discharges (BD), in which the current is limited by at least one dielectric layer, and the characteristic dimensions of the electrodes significantly exceed the interelectrode gap, are effective technologies for generating nonequilibrium plasma in gases at atmospheric pressure. The unique properties of barrier discharges determine their wide application in various technological processes, including ozone generation, surface modification, coating, pollution control, sterilization and disinfection, CO2 lasers, excimer lamps and plasma display panels (PDP). Intensive research into the properties of barrier discharges is closely related to their industrial application. Devices and installations using barrier discharges are constantly being improved in order to improve the characteristics of the corresponding process or device.
- Hits: 46
UDC:53+54(575.3)
EFFECT OF ANNEALING TEMPERATURE ON THE STRUCTURE AND THERMAL PROPERTIES OF GRAPHENE OXIDE-FILLED POLYETHYLENE
Rashidov D., Tabarov S.Kh., Ismatov Sh.P., Aknazarova Sh.I., Sodikov F., Dustov A.I.
Research Institute of Tajik National University
These days, 2D carbon structures - graphene structures - have attracted special attention from researchers in the formation of composite polymer materials [1, p. 5124]. However, the labor-intensive method of obtaining and the high cost of the resulting 2D structures practically exclude their use in the real practice of obtaining composite materials.
- Hits: 43
UDC 517.53.517.945
INTEGRAL DESCRIPTION AND SOLUTION OF THE TILE TYPE PROBLEM FOR ONE OF THE FOURTH ORDER DIFFERENTIAL EQUATIONS OF MIXED GENERATION
Sattorov A.S., Narzulloev Sh.Kh.
Tajik National University
The study of partial differential equations mainly developed at the end of the first half of the 20th century. in connection with solving physical problems. Many foreign and Soviet scientists are studying this class of equations [1-8].
A.V. Bitsadze [2] was the first to study the extremum principle for differential equations of mixed type when solving the Tricomi problem. M.V. Keldysh [3] proved the need to study the Tricomi problem for equations of mixed type depending on the accepted values of the coefficients of the lower order derivatives. E.I. Moiseev [4] solved the Tricomi problem for equations of mixed type in a special domain. MM. Smirnov [6] Tricomi problem for equations of mixed type in the researcher plane. In [7.8], boundary value problems for differential equations with singular coefficients of the second and higher orders are studied. In [9-14], an integral presented solution was found for one class of degenerate differential equations of the second and fourth orders. Some of these integral solution representations are used to solve Cauchy type problems in the characteristic domain.
- Hits: 43
UDC:323.3.015.31.51
AUTOMATION OF RUNGE-KUTT METHOD FOR APPROXIMATE SOLUTION OF DIFFERENTIAL EQUATIONS
Karomatulloi M., Saidzoda I.M.
Tajik State University of Finance and Economics,
Tajik National University
Introduction. After the collapse of the Soviet Union, the unified education system was destroyed and almost all post-Soviet republics changed their education system. Today, the education system of the Republic of Tajikistan needs international educational standards requires the use of active teaching methods, new approaches to education, knowledge, skills, abilities and high competence in the use of computer technology and modern information and communication technologies [1].
- Hits: 40
UDC:003.26:004.056.55
APPLICATION OF TRIGRAMS IN ENCRYPTION OF OBJECTS USING THE POLYBIUS SQUARE AND A DOUBLE KEY
Gafurov M.Kh., Rajabova A.S., Ghiyosov R.B.
Tajik Technical University named after academician M.S. Osimi
The works [1-2] consider the method of composing trigrams, its identification frequency (repetition) in Tajik literature and its use in identifying the author of a text in the Tajik language. The work [3] considers the methods of developing a set of encryption alphabets, the elements of which consist of symbols, the methods of creating an arbitrary encryption key and the method of encryption using symbols (unigrams) of the language. In [4] a method for creating an arbitrary operator-key is considered, which uses language symbols and the Polybius square. The work [5] considers the method of encrypting an object using a double key, which uses language symbols, and the work [6] presents a method of encrypting language elements.
- Hits: 49
UDC: 004.42
STEGANOGRAPHIC METHOD OF PROTECTING TEXT INFORMATION
Komilov O.O., Rustamova H.R.
Tajik National University
The problem of protecting information from unauthorized access arose in ancient times, and the emergence of the Internet and the formation of information and social networks made this problem even more real or important.
Today, there are several classical and modern methods of data protection, but for reliable protection it is recommended to use only these methods together.
Depending on the possibility of violating the security of information systems, physical, administrative and software, coding and legal methods of protection are used. Along with a reliable method of protecting information - encryption, there is also a steganographic method. If encryption hides information available or transmitted via a message from an outsider [1], the steganographic method, in turn, ensures the secret transfer of information, keeping the fact of transfer secret [2]. Such steganosystems are actively used to solve the following main tasks: protecting confidential information from unauthorized access, protecting intellectual property rights, eliminating monitoring and management systems of network resources [3].
- Hits: 52
UDC: 517.968
STUDY OF A CLASS OF OPERATOR-DIFFERENTIAL EQUATIONS OF THE SECOND ORDER
Zarifzoda S.K., Rozikov M.T., Bobiev M.M.
Tajik National University
Today, the theory of integro-differential equations is one of the independent areas of research, developing independently of other sections of mathematics. A detailed description of the achievements in this area before the sixties of the last century can be found in the article by M.M. Weinberg [1] (see also the bibliography in this work). The main feature of the theory of integro-differential equations is manifested in their two-dimensional nature. That is, in such equations, the unknown function appears both under the differential sign and under the integral sign. A mathematical description of the laws of development of systems containing hereditary information or dynamic memory, V. Volterra [2] (see monograph [2] and literature to it). A number of important results devoted to the study of integro-differential equations were published in the works of scientists I.N. Vekua [3], L.G. Magnaradze [4], N.A. Sidorov [5], M.V. Falaleev [6], S.S. Orlova [7] and others.
In recent years, a new theory of the class of integral equations with singular kernels was developed in the works of N. Rajabov [8], [9]. Based on these results, L.N. Rajabov [10] investigated two-dimensional integral equations of the Volterra type with singular kernels.