Доклады Академии наук Беларуси, 1997, Том 41, No.3 / Издания академии / Научные журналы
Доклады Академии наук Беларуси, 1997, Том 41, No.3
Том 41, Номер 3; май-июнь, 1997
Mateiko O.M., Tavgen O.I.
Linear representations of degree 2 and 3 of automorphism group of rank 2 free group.
Summary: The two- and three-dimensional linear representations of the automorphism group of the free group of rank two are classified up to equivalence.
Optimal control of discrete Volterra system by quadratic cost functional. pp.10--16
Summary: Discrete Volterra control systems with quadratic cost functional are considered. Some properties of discrete Volterra operator in l2 space are established. Solvability and uniqueness conditions are given for the optimal solution. The representations of the optimal control are derived both using the conjugate variables and the linear feedback control for frequency domain.
On self-similar solution of a system of three-wave interaction. pp.17--20
Summary: For the system of three partial differential equations of the special type were received two classes of self-similar solutions expressed respectively in terms of solutions of the fifth Painleve's equation and the nonlinear ordinary differential second order equation which is integrated (in a special case) in elementary functions.
Strict e-semidifferentials and extremality conditions. pp.21--26
Summary: New abstract extremality notion embracing various solution notions for optimization problems is introduced. Necessary and sufficient extremality conditions are stated in terms of strict e-semidifferentials and strict sets of e-normals.
One-dimensional invariant distributions on homogeneous spaces. pp.27--32
Summary: We show that every homogeneous space with an invariant one-dimensional vector distribution can be constructed from a certain homogeneous space of lower dimension by one and only one of the four constructions described in this work.
Four-dimensional homogeneous Einstein spaces of signature (2,2) with non-solvable symmetry group. pp.33--35
Summary: This paper presents the complete local classification of four-dimensional homogeneous spaces of non-solvable Lie groups with an invariant pseudo-Riemannian metric of signature (2,2), and this metric satisfies the Einstein equation R - lg = 0, where g is a metric, R is the Ricci tensor, l is an arbitrary real number.
On straightening of multidimensional dynamic systems. pp.36--38
Summary: The test for straightening multidimensional dynamic systems on the base of particular integrals was obtained.
Soika A.K., Boiko B.B., Vashkevich I.M.
Research of spark air discharge channel expansion by the method of plasma-metal contact.
Summary: The radial expansion rates of spark air discharge channels and their diameters over a broad range of discharge current frequencies at a discharges energy up to 50 kJ were experimentally measured. A new method of research based on a contact between the spark discharge plasma and the conductor metal has been used.
Parashchuk V.V., Gribkovsky V.P., Rusakov K.I., Prokopenya A.N.
Radiative processes at discharge in semiconductors. pp.43--47
Summary: Spatial properties of interaction between electromagnetic waves of the visible and microwave ranges for different semiconductors in linear and nonlinear approaches are analysed. Possible mechanisms of the microwave formation and the effect of its characteristics on the interaction process are considered. The calculation results are compared with the data for the streamer discharges.
Lebedinsky Yu.A., Predko K.G.
Characteristics of radiation in depth of scattering medium with nonspherical oriented particles. pp.48--52
Summary: The solution of radiation transfer equation in depth of scattering medium with parameters depending on the direction of incident light is obtained. The behaviour of depth attenuation parameter is analysed.
Sagaidak D.I., Fedoruk G.G., Shulitsky B.G.
Thin film composites of copper phthalocyanine-polymer obtained by vacuum deposition and plasma polymerization technique. pp.53--58
Summary: The composite films of copper phthalocyanine (CuPc) -- polyimide were prepared by vacuum codeposition of CuPc, pyromellitic dianhydride and diami-nodiphenyloxide followed by thermally induced imidization. The CuPc -- polymer composites were also deposited by the plasma polymerization technique. Benzene was used as the monomer. The thermally-induced transformation of CuPc alpha-form microcrystals into monomers and then into beta-form microcrystals in CuPc -- polyimide films was observed by means of visible spectra.
Dubkova V.I., Krutko N.P., Safonova A.M., Batura S.V., Apanasenok V.I.
Edge wetting angles and conversion depth of epoxy binder in compositions with nickel-containing carbon fibers.
Summary: Dynamics of edge wetting angles of nickel-containing carbon fibers (Ni--YB) by an epoxy binder and by some of its components depending on the fiber carbonization temperature and the metal content was analysed. An ambiguous influence of nickel-containing carbon fibers on the physicochemical processes taking place on the filler-epoxy binder interface was revealed. On the one hand, the introduction of metal into carbon fibers leads to the improvement of wetting nickel-containing carbon fibers by the epoxy binder. On the other hand, this results in reduction in conversion depth of epoxy oligomer into the three-dimensional product. Its low-molecular component was revealed to make a major contribution to the reduction in wetting angles of Ni--YB by the binder. At the same time it is found that improvement of wetting nickel-containing carbon fibers with epoxy oligomer matrix in contrast to the composites with unmodified carbon fibers is not a determinal factor in increasing the adhesion strength and improving physicomechanical characteristics.
Gavrilov V.B., Konev S.V., Demidchik Yu.E., Demidchik E.P.
Quantitative estimation of individual thyroxine sensitivity of lipid metabolism in human organism.
Summary: The pre-operational investigation of patients with thyroid gland cancer showed that the contents of thyroxine (T4) and low density lipoproteins (LDL) were in the limits of the norm and had no correlation (R = - 0.08). A parameter was proposed for the individual thyroxine sensitivity of the lipid metabolism, TL = T4(LDL/LDLmin - 1). After dividing the patients into subgroups according to the TL value, a high correlation between LDL and 1/T4 was observed within each subgroup (R ranging from 0.77 to 0.98). A high heterogeneity of patients in their individual thyroxine sensitivity was revealed, the variation of the TL value being 15-fold.
Nikandrov V.N., Vorobiova G.V., Murashko O.N., Pyzhova N.S., Kvyatkovskaya N.V., Bartalevich O.A., Danilovich T.V.
Interaction of streptokinase and plasminogen of human with oxidoreductases and pyruvate kinase: formation of stable complexes in water-saline solution. pp.69--75
Summary: The formation of equimolar complexes of streptokinase or plasminogen with lactate dehydrogenase, malate dehydrogenase, catalase and pyruvate kinase in pH 7.4, 3.0 and 10.0 aqueous solutions was demonstrated by means of difference spectroscopy. 6 M urea did not hinder the formation of enzyme complexes with streptokinase, as well as plasminogen complexes with catalase and pyruvate kinase. It is assumed, that in "plasminogen -- plasmin" system the formation of such complexes can regulate the processes, occurring with active oxygen species or with electron translocation participation.
Levkovets V.S., Soltanov V.V.
The role of humoral factors in changing the level of tissue catecholamines and structural disturbances of gastric mucosa of rats at ulcer formation. pp.76--79
Summary: Structural disturbances (haemorrhages) of the gastric mucosa and alterations of the level of tissue catecholamines due to mechanical injury of the duodenum after denervation of the gastro-duodenal region are caused by humoral mechanisms.
Buloichik A.A., Voluevich E.A.
Effects of alien cytoplasms on wheat resistance to natural powdery mildew population. pp.80--82
Summary: Polygenic resistance of wheat cultivar Penjamo 62 alloplasmic lines to natural powdery mildew population during the host -- plant ontogenesis was studied. In some cases genes which control the components of polygenic resistance can display similar phenotypic effect irrespectively of conditions of the testing year and the ontogenesis stage.
Demidchik V.V., Sokolik A.I., Yurin V.M.
Mechanisms of conductance modification in plant cell membranes under the action of trivalent iron ions. pp.83--87
Summary: The mechanisms of the modifying effect of trivalent iron ions on permeability of plasmalemma of the freshwater algae Nitella flexilis cells were studied. Fe3+ above 5 · 10-5 -- 10-4 M induced an increase in the nonspecific conductance and inhibited the light-stimulated electrogenic H+ATPase pump of plasmalemma. An elevation in the Ca+2 concentration shifted the effective iron level to ten-fold high range, but it did not influence the iron-induced effect on the H+ATPase pump. Following plausable explanation to the observed effect: iron ions are assumed to interact with lipid matrix of plasmalemma leading to their perturbation and growth in nonselective conductance, and with SH-group of the active site of the H+-ATPase pump leading to blocking of the enzyme activity.
Binary analysis of the genetic code structure on the basis of amino acid polarity and types of doublet nucleotides. pp.88--91
Summary: Distribution of 7 kinds of binary classified nucleotides (pyrines-pyrimidines, UA-CG, UG-CA, U-CAG, C-UAG, A-UCG, G-UCA) in codon doublets of amino acids with strong polarity and nonpolarity has been studied. It is demonstrated that pyrimidine content is much higher in the doublets of nonpolar amino acids while purines are more typical for the doublets of polar amino acids. Prevalence of U and A bases takes place in the doublets of nonpolar and polar amino acids respectively.
НАУКИ О ЗЕМЛЕ
Makhnach A.A., Sanko A.F., Kolosov I.L.
Stable carbon isotopes in modern mollusk shells in Belarus.
Summary: Variations of carbon isotopic composition of modern mollusk shells within the area of Belarus were determined. Interspecific isotopic variations within biotopes were revealed to be less significant than among them. The 13C content of lacustrine shells decreases with the eutrophication process development. The d13C values of shells from river sites were significantly lower than those of lacustrine shells.
Velichkevich F.Yu., Lesyak M.A.
On some extinct endocarp species from Poland, Belarus, Lithuania and Russia. pp.97--101
Summary: Fossil endocarps of Potamogeton genus have been examined from Pliocene flora Mizerna (Western Carpathian)in Poland. Endocarp collections of this genus from Belarus and other parts of the East-European plain have also been studied and compared. 18 species of the genus including 10 extinct Pliocene species have been distinguished. Short descriptions, comparisons and pictures of some of these species are given.
Makhnach N.A., Gulis L.F.
Spatial variations of dissolved silica concentrations and groundwater saturation index for quartz (Belarus, as an example). pp.102--106
Summary: Schematic map of the groundwater saturation index (Is) for quartz is composed and described. H4SiO4 concentrations in solutions as well as Is values were revealed to increase in terrain elements sequence: watershed top-gentle slope-river terrace-flood plain-bog. Is values were maximal within the areas of dominating hydromorphic and semihydromorphic soils and minimal in the fields of the autonomic soils prevalence.
Brasenia flora from the Lower Briniev horizon brown coal of Belarus Neogene. pp.107--111
Summary: Brasenia flora from the lower part of the Briniev horizon of the Neogene of Belarus and the fossil seeds of species Brasenia dorofeevii sp. nov. are described.
Yashcheritsyn P.I., Kozhuro L.M., Kheifets M.L., Chemisov B.P.
Designing technological complexes of high-effective treatment of products on the basis of multifactorial optimization.
Summary: Structural and parametric redundancy adaptation of subsystems and structures, centralization of material and information flows during designing technological complexes were considered.
Bogdanovich P.N., Tkachuk D.V.
Temperature field peculiarities under frictional interaction between plane and wavy surfaces. pp.119--122
Summary: The temperature field kinetic regularities has been investigated for frictional contact of the surface with regular waviness and the plane. A radial gradient of the contact spot temperature is shown to influence on the thermoelastic instability of contact.
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Разработана и поддерживается Николаем Н. Костюковичем. Последнее обновление: 6 сентября 2008 г.
Создана при участии Игнатия И. Корсака
Копирайт © 1997-2008 Национальная академия наук Беларуси
Копирайт © 1997 Издательство "Беларуская навука"