522 research outputs found

    ДОСЛІДЖЕННЯ ПАРАМЕТРІВ ІМПУЛЬСУ ДЕФОРМАЦІЙНОЇ ХВИЛІ ПРИ ПОВЕРХНЕВО ПЛАСТИЧНОМУ ЗМІЦНЕННІ

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    The article considers the issue of increasing the efficiency of shock energy and recording equipment for the study of the parameters of the deformation wave pulse. The review of the last researches and publications is carried out and perspective directions at designing of the special measuring equipment are established. A method is proposed and an experimental-measuring complex for the study of the momentum parameters in the deformation zone under different initial conditions is developed. The study of the parameters, of the shock pulse and micro hardness, of the strengthened material in the deformation zone using different versions, of the impact systems. It is established that when using a shock system with a step-shaped striker, the shock wave is characterized by a complex shape of the pulse. To assess the reliability of the obtained results, a test problem was solved in the environment of the Abaqus software package. When designing new technological processes of strengthening, the results of experimental studies such as the impact system and the parameters and modes of the processing process are of particular importance. It is established that the best result is shown by shock systems, which allow forming a prolonged shock pulse.The article considers the issue of increasing the efficiency of shock energy and recording equipment for the study of the parameters of the deformation wave pulse. The review of the last researches and publications is carried out and perspective directions at designing of the special measuring equipment are established. A method is proposed and an experimental-measuring complex for the study of the momentum parameters in the deformation zone under different initial conditions is developed. The study of the parameters, of the shock pulse and micro hardness, of the strengthened material in the deformation zone using different versions, of the impact systems. It is established that when using a shock system with a step-shaped striker, the shock wave is characterized by a complex shape of the pulse. To assess the reliability of the obtained results, a test problem was solved in the environment of the Abaqus software package. When designing new technological processes of strengthening, the results of experimental studies such as the impact system and the parameters and modes of the processing process are of particular importance. It is established that the best result is shown by shock systems, which allow forming a prolonged shock pulse

    Правосуб’єктність органів, які здійснюють державний нагляд у сфері праці: науково-правовий аспект (Legitimacy of institutions engaged state supervision in works: scientific and legal aspects.)

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    У цій статті висвітлені ключові питання правового становища органів, які здійснюють державний нагляд у сфері праці. Проаналізовані положення актів трудового законодавства, проекту Трудового кодексу. Обґрунтовується доцільність визначення системи органів, які здійснюють державний нагляд у сфері праці у майбутньому Трудовому кодексі. Зроблені відповідні висновки щодо вдосконалення законодавства. (This article deals with key issues of legal status of bodies exercising state supervision in the workplace. The provisions of labor law regulations, the draft Labour Code are analyzed. The expediency of defining the system of carrying out state supervision in the workplace in the future the Labor Code. Corresponding conclusions about legal regulation improvement are made.

    Planar channeling of electrons: Numerical analysis and theory

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    Monte Carlo results on electron channeling in silicon are presented. The simulation has been done with a new computer code that takes into account the detailed atomic structure of the crystal. The dechanneling lengths for (100), (110) and (111) crystallographic planes are estimated. The calculated dependence of the intensity of the channeling radiation on the crystal length demonstrats a good agreement with recent experimental data

    Instantaneous Radio Spectra of Giant Pulses from the Crab Pulsar from Decimeter to Decameter Wavelengths

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    The results of simultaneous multifrequency observations of giant radio pulses from the Crab pulsar, PSR B0531+21, at 23, 111, and 600 MHz are presented and analyzed. Giant pulses were detected at a frequency as low as 23 MHz for the first time. Of the 45 giant pulses detected at 23 MHz, 12 were identified with counterparts observed simultaneously at 600 MHz. Of the 128 giant pulses detected at 111 MHz, 21 were identified with counterparts observed simultaneously at 600 MHz. The spectral indices for the power-law frequency dependence of the giant-pulse energies are from -3.1 to -1.6. The mean spectral index is -2.7 +/- 0.1 and is the same for both frequency combinations (600-111 MHz and 600-23 MHz). The large scatter in the spectral indices of the individual pulses and the large number of unidentified giant pulses suggest that the spectra of the individual giant pulses do not actually follow a simple power law. The observed shapes of the giant pulses at all three frequencies are determined by scattering on interstellar plasma irregularities. The scatter broadening of the pulses and its frequency dependence were determined as tau_sc=20*(f/100)^(-3.5 +/- 0.1) ms, where the frequency f is in MHz.Comment: 13 pages, 1 figure, 1 table (originally published in Russian in Astronomicheskii Zhurnal, 2006, vol. 83, No. 7, pp. 630-637), translated by Georgii Rudnitski

    Развитие научных исследований на кафедре технической кибернетики Национального технического университета Украины «Киевского политехнического института»

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    Основні наукові досягнення та результати наукових досліджень кафедри технічної кібернетики Національного технічного університету України “Київського політехнічного інституту”.Basic scientific achievements and results of scientific researches of department of technical cybernetics of the National technical university of Ukraine of the “KPI”.Основные научные достижения и результаты научных исследований кафедры технической кибернетики Национального технического университета Украины «Киевского политехнического института»

    Giant Pulses -- the Main Component of the Radio Emission of the Crab Pulsar

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    The paper presents an analysis of dual-polarization observations of the Crab pulsar obtained on the 64-m Kalyazin radio telescope at 600 MHz with a time resolution of 250 ns. A lower limit for the intensities of giant pulses is estimated by assuming that the pulsar radio emission in the main pulse and interpulse consists entirely of giant radio pulses; this yields estimates of 100 Jy and 35 Jy for the peak flux densities of giant pulses arising in the main pulse and interpulse, respectively. This assumes that the normal radio emission of the pulse occurs in the precursor pulse. In this case, the longitudes of the giant radio pulses relative to the profile of the normal radio emission turn out to be the same for the Crab pulsar and the millisecond pulsar B1937+21, namely, the giant pulses arise at the trailing edge of the profile of the normal radio emission. Analysis of the distribution of the degree of circular polarization for the giant pulses suggests that they can consist of a random mixture of nanopulses with 100% circular polarization of either sign, with, on average, hundreds of such nanopulses within a single giant pulse.Comment: 13 pages, 6 figures (originally published in Russian in Astronomicheskii Zhurnal, 2006, vol. 83, No. 1, pp. 62-69) translated by Denise Gabuzd

    Particle Number Fluctuations in the Microcanonical Ensemble

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    Particle number fluctuations are studied in the microcanonical ensemble. For the Boltzmann statistics we deduce exact analytical formulae for the microcanonical partition functions in the case of non-interacting massless neutral particles and charged particles with zero net charge. The particle number fluctuations are calculated and we find that in the microcanonical ensemble they are suppressed in comparison to the fluctuations in the canonical and grand canonical ensembles. This remains valid in the thermodynamic limit too, so that the well-known equivalence of all statistical ensembles refers to average quantities, but does not apply to fluctuations. In the thermodynamic limit we are able to calculate the particle number fluctuations in the system of massive bosons and fermions when the exact conservation laws of both the energy and charge are taken into account.Comment: REVTeX, 17 pages, 9 figures, v3: misprints a correcte
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