999 resultados para otwarta nauka


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The nonlinear effect of hf surface waves self-interaction in a magnetoactive planar plasma waveguide is studies. The waveguide structure under consideration can be formed by gaseous or semiconducting homogeneous plasma, which is limited by a perfectly conducting metal surface. The surface (localized near the surface) wave perturbations propagating on the plasma-metal boundary perpendicular to the constant external magnetic field, are investigated. The nonlinear frequency shift connected with interaction of the second harmonic and static surface perturbations with the main frequency wave, is determined using the approximation of weak nonlinearity. It is shown that the process of double-frequency signal generation is the dissipative one as a result of bulk wave excitation on the surface wave second harmonic.

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In approximation of weak heating influence of electron heating in the high-frequency surface wave field on propagation of surface wave (heating nonlinearity) is considered. It is shown that high-frequency surface wave propagates in direction perpendicular to the external magnetic field at the semiconductor-metal interface. A nonlinear dispersion equation is obtained and studied that allows to make conclusions about the contribution of heating nonlinearity to nonlinear process of considered interaction.

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Dispersion characteristics and topography of electromagnetic fields of axially symmetric surface waves (SW) and of azimuth surface waves (ASW) propagating in a structure composed of a cylindrical metal antenna and magnetoactive plasma are investigated. The antenna and plasma may be separated by a vacuum layer. The dispersion characteristics of SW and ASW are presented as functions of the antenna and the magnetoactive plasma parameters. Close agreement between theory and experimental results are shown. Surface impedances of the SW and ASW are calculated for various parameters of the problem.

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The efficiency of the excitation of surface plasma waves in the presence of external, steady crossed magnetic and electric fields is studied analytically and numerically for a geometry in which the waves propagate along the interface between a plasma-like medium and a metal in the direction transverse to both fields. The magnetic and electric fields are assumed to be parallel and transverse to the interface, respectively. The condition for which the drift instability of the surface wave arises is found.

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Species specific LTR retrotransposons were first cloned in five rare relic species of drug plants located in the Perm’ region. Sequences of LTR retrotransposons were used for PCR analysis based on amplification of repeated sequences from LTR or other sites of retrotransposons (IRAP). Genetic diversity was studied in six populations of rare relic species of plants Adonis vernalis L. by means of the IRAP method; 125 polymorphic IRAP markers were analyzed. Parameters for DNA polymorphism and genetic diversity of A. vernalis populations were determined.

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Species specific LTR retrotransposons were first cloned in five rare relic species of drug plants located in the Perm’ region. Sequences of LTR retrotransposons were used for PCR analysis based on amplification of repeated sequences from LTR or other sites of retrotransposons (IRAP). Genetic diversity was studied in six populations of rare relic species of plants Adonis vernalis L. by means of the IRAP method; 125 polymorphic IRAP markers were analyzed. Parameters for DNA polymorphism and genetic diversity of A. vernalis populations were determined.

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The overall rate equation for a reaction sequence consisting of a pre-equilibrium and rate-determining steps should not be derived on the basis of the concentration of the intermediate product (X). This is apparently indicated by transition state theory (as the path followed to reach the highest energy transition state is irrelevant), but also proved by a straight-forward mathematical approach. The thesis is further supported by the equations of concurrent reactions as applied to the partitioning of X between the two competing routes (reversal of the pre-equilibrium and formation of product). The rate equation may only be derived rigorously on the basis of the law of mass action. It is proposed that the reactants acquire the overall activation energy prior to the pre-equilibrium, thus forming X in a high-energy state en route to the rate-determining transition state. (It is argued that conventional energy profile diagrams are misleading and need to be reinterpreted.) Also, these arguments invalidate the Michaelis-Menten equation of enzyme kinetics, and necessitate a fundamental revision of our present understanding of enzyme catalysis. (The observed ``saturation kinetics'' possibly arises from weak binding of a second molecule of substrate at the active site; analogous conclusions apply to reactions at surfaces).

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This work presents a new electrode, 2-benzoylnaphtho 2,1-b]furan hydrazone exfoliated graphite paste electrode (B-EGPE) fabricated for the differential pulse anodic stripping voltammetric determination of lead (Pb). Under the optimal conditions, Pb2+ could be detected in the concentration range from 2.75 x 10(-7) to 1.5 x 10(-6) mol/L with the linear regression equation, y = 19.41 x 10(-6) x + 0.4249 x 10(-9) with R = 0.99. Interferences from other ions were investigated and the proposed method was further applied to the trace levels of Pb2+ detection in real samples with satisfactory results.

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The results obtained during the third phase of Nauka are reported concerning the standing stock estimates, population length structure and gonad development of scad and mackerel stocks and the catch composition in Mozambican waters.

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Integracja europejska jest z pewnością zjawiskiem mającym obecnie największy wpływ na przemiany mentalne, społeczne i polityczne naszego społeczeństwa. Członkowstwo w Zjednoczonej Europie mobilizuje nas do porównań i weryfikacji dotychczasowych idei i sposobów wprowadzania ich w życie społeczne. Nauczanie języków obcych jest domeną, w której zmiany są szczególnie widoczne, gdyż to właśnie znajomość języków staje się podstawowym warunkiem uczestnictwa w komunikacji europejskiej i, co się z tym łączy, podstawowym wyzwaniem w edukacji młodych ludzi-członków zjednoczonej Europy. Nowe wyzwania wynikające z przemian ostatnich czasów odnoszą się do wielu aspektów w kształceniu językowym wpisującego się w szeroko pojętą edukację. Do najważniejszych zaliczyć można: realizację humanistycznego ideału wychowania i kształcenia, kładącego nacisk na otwartość wobec odmienności kulturowej, tolerancję i wychowanie w duchu demokracji, a także na prawo do odmienności i funkcjonowania każdego człowieka, przygotowanie i kształcenie ustawiczne nauczycieli języków obcych poprzez ujednolicenie tzw. standardów nauczania przy jednoczesnym respektowaniu indywidualnych celów nauki języków, podnoszenie jakości kształcenia językowego poprzez skoncentrowanie działań dydaktycznych na osobie ucznia, tworzeniu tożsamości (wielo)językowej, wdrażaniu do autonomii. (Z przedmowy)

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Wydział Historyczny: Instytut Historii

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Wydział Historyczny: Instytut Etnologii i Antropologii Kulturowej