115 research outputs found

    Realization of Pedagogical Conditions for the Formation of General Scientific Competence of the Future Bachelors of Machine Engineering Specialties

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    The article reveals the expediency of applying pedagogical conditions for the formation of general scientific competence of the future bachelors of machine engineering specialties. It is indicated that their implementation will positively influence not only the professional qualities of future bachelors, but also the formation of world outlook positions, moral beliefs, and the nature of thinking. It indicates the promotion of the development of spirituality and a common culture, the ability of interpersonal communication

    Image Super-Resolution via Wavelet Feature Extraction and Sparse Representation

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    This paper proposes a novel Super-Resolution (SR) technique based on wavelet feature extraction and sparse representation. First, the Low-Resolution (LR) image is interpolated employing the Lanczos operation. Then, the image is decomposed into sub-bands (LL, LH, HL and HH) via Discrete Wavelet Transform (DWT). Next, the LH, HL and HH sub-bands are interpolated employing the Lanczos interpolator. Principal Component Analysis (PCA) is used to reduce and to obtain the most relevant features information from the set of interpolated sub-bands. Overlapping patches are taken from the features obtained via PCA. For each patch, the sparse representation is computed using the Orthogonal Matching Pursuit (OMP) algorithm and the LR dictionary. Subsequently, this sparse representation is used to reconstruct a High-Resolution (HR) patch employing the HR dictionary and it is added to the LR image. By applying the quality objective criteria PSNR and SSIM, the novel technique has been evaluated demonstrating the superiority of the novel framework against state-of-the-art techniques

    Optically-stimulated desorption of 'hot' excimers from pre-irradiated Ar solids

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    Electronically-induced desorption from solid Ar pre-irradiated by a low-energy electron beam was investigated by activation spectroscopy methods - photon-stimulated exoelectron emission and photon-stimulated luminescence in combination with spectrally-resolved measurements in the VUV range of the spectrum. Desorption of vibrationally excited argon molecules Ar2^*(v) from the surface of pre-irradiated solid Ar was observed for the first time. It was shown that desorption of 'hot' Ar2^*(v) molecules is caused by recombination of self-trapped holes with electrons released from traps by visible range photons. The possibility of optical stimulation of the phenomenon is evidenced.Comment: The complete version of the paper will be published in Fiz. Nizk. Temp. (Low Temp. Phys.

    Electron traps in solid Xe

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    Correlated real-time measurements of thermally stimulated luminescence and exoelectron emission from solid Xe pre-irradiated with an electron beam were performed. The study enabled us to distinguish between surface and bulk traps in solid Xe and to identify a peak related to electronically induced defects. The activation energy corresponding to annihilation of these defects was estimated by the following methods: the method of different heating rates, the initial-rise method, and the curve cleaning technique with fitting of the thermally stimulated luminescence glow curve

    Optical and structural characterization of Ge clusters embedded in ZrO2

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    The change of optical and structural properties of Ge nanoclusters in ZrO2 matrix have been investigated by spectroscopic ellipsometry versus annealing temperatures. Radio-frequency top-down magnetron sputtering approach was used to produce the samples of different types, i.e. single-layers of pure Ge, pure ZrO2 and Ge-rich-ZrO2 as well as multi-layers stacked of 40 periods of 5-nm-Ge-rich-ZrO2 layers alternated by 5-nm-ZrO2 ones. Germanium nanoclusters in ZrO2 host were formed by rapid-thermal annealing at 600-800 ∘C during 30 s in nitrogen atmosphere. Reference optical properties for pure ZrO2 and pure Ge have been extracted using single-layer samples. As-deposited multi-layer structures can be perfectly modeled using the effective medium theory. However, annealed multi-layers demonstrated a significant diffusion of elements that was confirmed by medium energy ion scattering measurements. This fact prevents fitting of such annealed structure either by homogeneous or by periodic multi-layer model

    Problems of surgical complications of radical cystectomy: experience one clinic

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    The structure of early postoperative complications of 426 patients, who were divided into 3 groups depending on the type of surgical assimilation of this type of operation, was analyzed retrospectively. Intercommunication between development of severe complications and somatic status of the patient, or any operative interventions in past medical history, was studied.Структура ранних послеоперационных осложнений 426 пациентов, которые были разделены на 3 группы в зависимости от типа хирургического усвоения этого типа операции, была подвергнута ретроспективному анализу. Взаимосвязь между развитием тяжелых осложнений и соматического состояния пациента, или каких-либо оперативных вмешательств в анамнезе, была изучена

    Impulsive Fermi magnon-phonon resonance in antiferromagnetic CoF2CoF_{2}

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    Understanding spin-lattice interactions in antiferromagnets is one of the most fundamental issues at the core of the recently emerging and booming fields of antiferromagnetic spintronics and magnonics. Recently, coherent nonlinear spin-lattice coupling was discovered in an antiferromagnet which opened the possibility to control the nonlinear coupling strength and thus showing a novel pathway to coherently control magnon-phonon dynamics. Here, utilizing intense narrow band terahertz (THz) pulses and tunable magnetic fields up to 7 T, we experimentally realize the conditions of the Fermi magnon-phonon resonance in antiferromagnetic CoF2CoF_{2}. These conditions imply that both the spin and the lattice anharmonicities harvest energy transfer between the subsystems, if the magnon eigenfrequency fmf_{m} is twice lower than the frequency of the phonon 2fm=fph2f_{m}=f_{ph}. Performing THz pump-infrared probe spectroscopy in conjunction with simulations, we explore the coupled magnon-phonon dynamics in the vicinity of the Fermi-resonance and reveal the corresponding fingerprints of an impulsive THz-induced response. This study focuses on the role of nonlinearity in spin-lattice interactions, providing insights into the control of coherent magnon-phonon energy exchange

    Perturbative regime of terahertz high-harmonics generation in topological insulators

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    In this Letter, terahertz high harmonic generation processes in topological insulators of the bismuth and antimony chalcogenides family are investigated. Field conversion efficiencies are determined and clean cubic and quintic power-law scaling is observed for third and fifth harmonics, up to driving terahertz fields of 140 kV/cm. This is in contrast to all previous experiments on terahertz harmonics generation in Dirac materials where a non-perturbative regime has been observed already at few 10s kV/cm driving fields. Our nonlinear THz spectroscopy experiments are complemented by THz pump - optical probe measurements showing distinctly different relaxation dynamics of the carriers in the topologically-protected Dirac states at the surfaces and the bulk. The THz-induced dynamics of surface states reveal ultrafast relaxation that prevents accumulation effects, and results in a clear perturbative regime of THz harmonics generation that is different to graphene or Dirac semimetals with their slower relaxation times in the few ps regime
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