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St. Petersburg Polytechnical University Journal: Physics and Mathematics
ISSN 2405-7223 · Peter the Great St.Petersburg Polytechnic University · 426 artikel di indeks
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Nonlinear reduced order models for elastic structures
The problem of synthesizing the reduced-order dynamic models for continuous elastic systems in a geometrically nonlinear formulation (primarily thin-walled structures) based on the finite element method is considered. The approaches under consideration are based on the idea of identifying the…
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Temperature effects on the light current-voltage characteristics of the heterojunction solar cells fabricated on gallium-doped silicon substrates
In this study, the impacts of temperature on the light current-voltage characteristics of heterojunction solar cells fabricated on gallium-doped crystalline p-type silicon (c-Si) has been studied under air mass zero spectrum (136.7 mW/сm²) in the temperature range from 173 to 373 K. Our…
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A natural convection airflow and its heat transfer around a single horizontal finned tube
The paper presents the results of numerical investigation of a natural convective airflow and its heat transfer forming around a single horizontal finned tube (the ratio of a fin diameter to the base tube one is 2.15). Calculations have been carried out at a Rayleigh number Ra = 2×10^7 or less…
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Dependence of optical spectra of bulk-doped cadmium sulfide semiconductor nanocrystals on their geometrical dimensions and number of charge carriers
The theoretical study of dipole plasmon resonances in bulk-doped CdS semiconductor nanocrystals has been continued. In this paper, the case of a larger number of free carriers in a nanocrystal was considered. It was demonstrated that the giant dipole resonance dominated in the photoabsorption…
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Comparison of elliptic flows of π0 mesons in Cu + Au collisions at 200 GeV and U + U collisions at 193 GeV
This paper presents the findings of investigation of the elliptic flows of π0 mesons as functions of transverse momentum for different centrality classes of relativistic nuclei Cu + Au collisions at an energy of 200 GeV and U + U collisions at 193 GeV. A comparison of the obtained values is also…
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Measurement of the timing jitter of a low-noise single photon detector
The article puts forward a technique for measuring the time jitter of a single photon detector (SPD). The proposed method does not require high-speed electronics and short optical pulses. The procedure involves experimental measurement of the time delays of the SPD response to short weak optical…
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The resistive switching effect in the n-GaN/p-Si heterostructures
In the paper, the findings of study the memristor based on n-GaN nanowires synthesized on silicon by the molecular beam epitaxy with SiN and AlN interface layers have been presented. The polarity inversion of writing voltage was found to depend on the interface preparation method. In addition, it…
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The photodegradation of the free and bound Radachlorin solutions: A comparative study
The comparative photodegradation studies of a free photosensitizer Radachlorine and Radachlorine being a part of the triple selenium-containing nanosystem (PS-2) based on the amphiphilic molecular brush (AMB) with a cellulose backbone and side chains of polymethacrylic acid (bound Radachlorine)…
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Application of the catastrophe theory to describe temperature dependencies of the breakdown field strength in polymer dielectrics
An equation expressing the dependence of the breakdown field strength of polymer dielectrics on ambient temperature has been derived based on the hypothesis of an analogy between the physical phenomenon of breakdown and the mathematical cusp catastrophe. The parameters of this equation were…
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Thermally stimulated relaxation of surface potential in polylactide-based composite films
The stability of the electret state in polylactide films with a white soot dispersed filler has been studied using the method of thermally stimulated relaxation of the surface potential. The best electret properties were shown to exhibit by the films with a filler content of at least 4%, and the…
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Electronic and magnetic properties of hausmannite
In this work, the magnetic and electronic properties of the mineral hausmannite (Mn3O4) have been studied using both experimental and theoretical methods. Magnetic susceptibility χ was measured in the paramagnetic region over the temperature range of 288–1000 K using the Faraday method. The…
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Numerical study of the light extraction efficiency from gallium phosphide nanowires integrated with a gold nanoparticle
In order to develop the fabrication technology of GaP nanowires (NWs) integrated with Au nanoparticles (NPs), i.e., of an object promising for creating red-range micro-LEDs, its light extraction efficiency has been analyzed both with and without the Au NP. Moreover, the relationship between this…
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Photoelectric properties of diodes based on magnesium silicide semiconductor
In this work, an indirect-gap semiconductor Mg2Si has been synthesized and studied. Mg2Si was formed as a 682 nm thick polycrystalline film (the formation was established using Raman scattering and Fourier-transform IR spectroscopies). X-ray phase analysis revealed that the Mg2Si (220)…
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Size-dependent adsorption and electronic modulation of pyrene nanostructures toward toxic gas detection: a DFT study
The DFT-study at the B3LYP/6-31G level has been conducted to analyze the interactions of pyrene-based graphene fragments with toxic gases F2, AsH3, PH3, and HF. Three diamond-shaped n-pyrene clusters (n = 3, C30H14; n = 4, C48H18; n = 5, C70H22) were systematically optimized, and their adsorption…
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The response of an intermodal fiber-optic interferometer with SMSMS structure in case of spectral interrogation to changes in the refractive index of the external environment
The operation of an intermode fiber-optic interferometer with “Singlemode-Multimode-Singlemode-Multimode-Singlemode" (SMSMS) structure during its spectral interrogation in the C-wavelength range has been studied. The refractive index n of the external environment can be measured using this device…
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Nondestructive testing of optical fibers using the optical coherence tomography
Optical coherence tomography (OCT) is a widely used imaging technique in biomedical research and non-destructive testing. It provides high spatial resolution, but for some applications, such as non-destructive testing, a further improvement in resolution is required. The paper presents an approach…
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The length distribution of nanowires with forward and backward surface diffusion
The length distributions of III – V nanowires growing by direct impingement and surface diffusion of adatoms are of fundamental and instrumentation interest. Here, we study kinetic rate equations for the length distribution of nanowires with forward and backward surface diffusion along their…
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Analytical quadrature formulae for electric fields of the RF straight-axis ion funnels of a general type
The article presents analytical quadrature expressions for electric field potentials that correspond to radio-frequency straight-axis ion funnels of a general type, specifically, the funnels with a curved channel profile, with multipole diaphragms, and with unequally spaced electrodes. When…
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Artikel Jurnal
Memristor effect in heterostructures based on gallium nitride nanowires on silicon
In this work, experimental and theoretical studies of diode heterostructures based on GaN nanowires synthesized on silicon have been carried out. Current-voltage measurements showed the typical backward diode behavior in the range from –3 to +3 V and the appearance of a hysteresis loop at greater…
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Artikel Jurnal
Feasibility to measure the properties of identified charged hadrons in collisions of xenon nuclei with a fixed tungsten target at an energy of 2.5A GeV in the MPD detector at the NICA collider
We report results on a feasibility study of measuring the properties of identified charged light hadrons (π± and K± mesons as well as protons) in collisions of Xe nuclei with a fixed tungsten target at an energy of 2.5A GeV using the MPD detector at the NICA collider. The evaluations of the purity…