Професор Г.Л. Кулініч (09.12.1938 – 10.02.2022) – видатний вчений і педагог

Pages of the article in the issue: 11 - 21 Language of the article: UkrainianСторінки у випуску: 11 - 21 Мова статті: українськ

Observations of comets C/2002 T7 (LINEAR) and 2P/Encke at Andrushivka

Photometric and spectral observations of C/2002 T7 (LINEAR) and 2P/Encke were made with the Zeiss-600 telescope at the Andrushivka Astronomical Observatory in November 2003. CCD imaging of the comets was carried out with narrowband HB filters CN, RC, and BC. The total number of CN molecules, gas production rate for CN, and Afρ value for the dust coma were obtained. The optical spectra of Comet C/2002 T7 (LINEAR) were obtained and reduced for the wavelength range 4200–7300 Å. The reddening gradient is derived for th

FPGA-Implemented Fractal Decoder with Forward Error Correction in Short-Reach Optical Interconnects

Forward error correction (FEC) codes combined with high-order modulator formats, i.e., coded modulation (CM), are essential in optical communication networks to achieve highly efficient and reliable communication. The task of providing additional error control in the design of CM systems with high-performance requirements remains urgent. As an additional control of CM systems, we propose to use indivisible error detection codes based on a positional number system. In this work, we evaluated the indivisible code using the average probability method (APM) for the binary symmetric channel (BSC), which has the simplicity, versatility and reliability of the estimate, which is close to reality. The APM allows for evaluation and compares indivisible codes according to parameters of correct transmission, and detectable and undetectable errors. Indivisible codes allow for the end-to-end (E2E) control of the transmission and processing of information in digital systems and design devices with a regular structure and high speed. This study researched a fractal decoder device for additional error control, implemented in field-programmable gate array (FPGA) software with FEC for short-reach optical interconnects with multilevel pulse amplitude (PAM-M) modulated with Gray code mapping. Indivisible codes with natural redundancy require far fewer hardware costs to develop and implement encoding and decoding devices with a sufficiently high error detection efficiency. We achieved a reduction in hardware costs for a fractal decoder by using the fractal property of the indivisible code from 10% to 30% for different n while receiving the reciprocal of the golden ratio

Double hadron leptoproduction in the nuclear medium

First measurement of double-hadron production in deep-inelastic scattering has been measured with the HERMES spectrometer at HERA using a 27.6 GeV positron beam with deuterium, nitrogen, krypton and xenon targets. The influence of the nuclear medium on the ratio of double-hadron to single-hadron yields has been investigated. Nuclear effects are clearly observed but with substantially smaller magnitude and reduced $A$-dependence compared to previously measured single-hadron multiplicity ratios. The data are in fair agreement with models based on partonic or pre-hadronic energy loss, while they seem to rule out a pure absorptive treatment of the final state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter

First Measurement of the Tensor Structure Function b1b_1 of the Deuteron

The \Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of \Hera. The use of a tensor polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry \At and the tensor structure function \bd for average values of the Bj{\o}rken variable $0.01<0.45$ and of the squared four-momentum transfer $0.5 {\rm GeV^2} <5 {\rm GeV^2}$. The quantities \At and \bd are found to be non-zero. The rise of \bd for decreasing values of $x$ can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering

The definition of the paramethers of superconducting film for production of protection equipment against electromagnetic environmental effects

The definition of the paramethers of superconducting film for production of protection equipment against electromagnetic environmental effects / NataliiaYeromina, Ivan Kravchenko, Igor Kobzev, Maksym Volk, Viktor Borysenko, Viktoriia Lukyanova, Yurii Gnusov, Yurii Horelov, Oleh Rikunov, Sergiy Kaplun // International Journal of Emerging Technology and Advanced Engineering. – 2021. – № 11 (7). – Р. 38-47. –DOI: https://doi.org/10.46338/ijetae0721_06У роботі представлені результати оцінки поширення плоскої електромагнітної хвилі (ЕМВ) по поверхні плівки з високотемпературного надпровідника (ВТСП) як у надпровідному S, так і в нормальному станах N, а також аналіз параметрів тонкої плівки HTS необхідно реалізацію пристрою захисту від електромагнітного випромінювання. Оцінка поширення ЕМВ на поверхні тонкої плівки ВТСП проводилася на основі дворідинної моделі. В результаті дослідження, отримані співвідношення для визначення величини поверхневого імпедансу та глибини проникнення ЕМВ у надпровідну плівку в S- та N-станах. Показано, що вираз визначення глибини проникнення ЭМВ надпровідну плівку в нормальному N-стані застосовна за умови, що частота сигнального поля не перевищує критичного значення, яке визначається енергією зв'язку носіїв заряду при температурі, що не перевищує температури переходу в надпровідний стан. На основі співвідношень для визначення поверхневого імпедансу тонкої плівки ВТСП отримані співвідношення для активного поверхневого опору, що є справжньою частиною поверхневого імпедансу, і поверхневий реактивний опір, що є його уявною частиною, у надпровідному та нормальному станах. Використовуючи ці відносини, запроваджується параметр якості тонкої плівки ВТСП. Залежність добротності плівки ВТСП від неї товщина знайдено. Показано, що найбільше значення добротності реалізується при товщині плівки менше або глибини проплавлення. Зазначається, що ця залежність справедлива лише в тому випадку, якщо товщина плівки не залежить на його якість.The paper presents the results of evaluating the propagation of a plane electromagnetic wave (EMW) over the surface of a film made of a high-temperature superconductor (HTS) in both superconducting S and normal N states, as well as an analysis of the parameters of a thin HTS film necessary for implementing a device for protection against electromagnetic radiation. Evaluation of the propagation of EMW over the surface of a thin HTS film was performed on the basis of a two-fluid model. As a result of the research, relations were obtained for determining the value of the surface impedance and the depth of penetration of EMW into a superconducting film in S and N states. It is shown that the expression for determining the penetration depth of EMW into a superconducting film in the normal N state is applicable provided that the frequency of the signal field does not exceed the critical value, which is determined by the binding energy of charge carriers at a temperature not exceeding the transition temperature to the superconducting state. Based on the relations for determining the surface impedance of a thin HTS film, relations are obtained for the active surface resistance, which is the real part of the surface impedance, and the surface reactance, which is its imaginary part, in the superconducting and normal states. Using these ratios, the quality parameter of the HTS thin film is introduced. The dependence of the quality factor of the HTS film on its thickness is found. It is shown that the highest value of the quality factor is realized when the film thickness is less than or of the order of the penetration depth. It is noted that this dependence is valid only if the film thickness does not depend on its quality.В работе представлены результаты оценки распространения плоской электромагнитной волны (ЭМВ) по поверхности пленки из высокотемпературного сверхпроводника (ВТСП) как в сверхпроводящем S, так и в нормальном N состояниях, а также анализ параметров тонкой пленки HTS не обходимо на реализацию устройства защиты от электромагнитного излучения. Оценка распространения ЭМВ по поверхности тонкой пленки ВТСП проводилась на основе двухжидкостной модели. В результате исследования, получены соотношения для определения величины поверхностного импеданса и глубины проникновения ЭМВ в сверхпроводящую пленку в S- и N-состояниях. Показано, что выражение для определения глубины проникновения ЭМВ в сверхпроводящую пленку в нормальном N-состоянии применима при условии, что частота сигнального поля не превышает критического значения, которое определяется энергией связи носителей заряда при температуре, не превышающей температуры перехода в сверхпроводящее состояние. На основе соотношений для определения поверхностного импеданса тонкой пленки ВТСП получены соотношения для активного поверхностного сопротивления, представляющего собой действительную часть поверхностного импеданса, и поверхностное реактивное сопротивление, являющееся его мнимой частью, в сверхпроводящем и нормальном состояниях. Используя эти отношения, вводится параметр качества тонкой пленки ВТСП. Зависимость добротности пленки ВТСП от ее толщина найдена. Показано, что наибольшее значение добротности реализуется при толщине пленки меньше или порядка глубины проплавления. Отмечается, что эта зависимость справедлива только в том случае, если толщина пленки не зависит на его качество

Subleading-twist effects in single-spin asymmetries in semi-inclusive deep-inelastic scattering on a longitudinally polarized hydrogen target

Single-spin asymmetries in the semi-inclusive production of charged pions in deep-inelastic scattering from transversely and longitudinally polarized proton targets are combined to evaluate the subleading-twist contribution to the longitudinal case. This contribution is significantly positive for (\pi^+) mesons and dominates the asymmetries on a longitudinally polarized target previously measured by \hermes. The subleading-twist contribution for (\pi^-) mesons is found to be small

Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target

Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion ($\phi$) and the target spin axis ($\phi_S$) about the virtual photon direction and relative to the lepton scattering plane. The extracted Fourier component \cmpi is a signal of the previously unmeasured quark transversity distribution, in conjunction with the so-called Collins fragmentation function, also unknown. The Fourier component \smpi of the asymmetry arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson productio

Quark helicity distributions in the nucleon for up, down, and strange quarks from semi--inclusive deep--inelastic scattering

Polarized deep--inelastic scattering data on longitudinally polarized hydrogen and deuterium targets have been used to determine double spin asymmetries of cross sections. Inclusive and semi--inclusive asymmetries for the production of positive and negative pions from hydrogen were obtained in a re--analysis of previously published data. Inclusive and semi--inclusive asymmetries for the production of negative and positive pions and kaons were measured on a polarized deuterium target. The separate helicity densities for the up and down quarks and the anti--up, anti--down, and strange sea quarks were computed from these asymmetries in a ``leading order'' QCD analysis. The polarization of the up--quark is positive and that of the down--quark is negative. All extracted sea quark polarizations are consistent with zero, and the light quark sea helicity densities are flavor symmetric within the experimental uncertainties. First and second moments of the extracted quark helicity densities in the measured range are consistent with fits of inclusive data