Научные публикации / Препринты

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КОЛЛЕКЦИЯ НАХОДИТСЯ В СТАДИИ РАЗРАБОТКИ

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10 uJ Nanosecond Pulsed Ytterbium fiber Laser With Arbitrary Pulse Shape
(2020) Trikshev, A. I.; Kamynin, V. A.; Tsvetkov, V. B.
We report on Yb-doped fiber laser capable of generating temporally shaped pulses at 1064 nm with 4-ns shaping resolution. The pulses are generated by modulation of a continuous-wave laser and subsequent amplification by a 2-stage fiber amplifier. Such laser can be used as seed in more powerful solid state laser systems.
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11C-methionine and 18F- fluorodeoxyglucose PET/CT in diagnosis of brain gliomas heterogeneity ПЭТ/КТ С 11С-МЕТИОНИНОМ И 18F-ФТОРДЕЗОКСИГЛЮКОЗОИ В ИЗУЧЕНИИ ГЕТЕРОГЕННОСТИ ГЛИОМ ГОЛОВНОГО МОЗГА
(2021) Vikhrova, N. B.; Batalov, A. I.; Konakova, T. A.; Khokhlova, E. V.; Kalaeva, D. B.; Postnov, A. A.; Калаева, Диана Борисовна
© 2021 Russian Electronic Journal of Radiology. All rights reserved.Purpose. The study of plastic and energy metabolism and their correlation with various histologic types of brain gliomas. Assessment of heterogeneity tumor structure and adjacent brain tissues by comparing MRI and 11C-methionine and 18F-fluorodeoxyglucose PET/CT data. Materials and methods. 52 patients (M/F 27/25, average age 48±12 years) with gliomas were enrolled in this study: glioblastoma (n = 19), anaplastic astrocytoma (n=9), diffuse astrocytoma (n=9), anaplastic oligodendroglioma (n=6), oligodendroglioma (n=6). Research protocol consisted from MRI before (T2, T2-FLAIR, 3DT1 (FSPGR) and after contrast enhancement (2DT1 (SE)) and dynamic MET and FDG PET/CT. Quantification parameters were: tumor to normal index (T/N) at last 10 min of time-activity curve (reflects the activity of metabolic processes), T/N in first peak of maximum uptake (Pmax) during first 60sec of study (reflects delivery level of radiopharmaceutical agent). Measurements were made in three areas: 1 – tumor core, 2 – edema/infiltration, 3 – intact brain tissue in close vicinity to the tumor borders (outside the T2-FLAIR hyperintensity zone). Сomparison was made between areas 1 and 2, 2and 3, and with intact brain tissue reference; MET and FDG accumulation correlations were studied. Results. Significant differences in T/N MET between areas 1 and 2 were obtained in all gliomas (p <0.05). Pmax MET differed only in glioblastomas (p <0.0001) and oligodendrogliomas (p <0.05), which correlated with the high level of vascularization of these tumor types. T/N FDG significantly differed between area 2 and 3 (p <0.05), which might allow to evaluate the boundaries of infiltrative growth of glioma, with mandatory comparison with MRI. Strong stable correlations of plastic and energy metabolism (as well as high level of radiopharmaceutical agent delivery) in the core of astrocytomas (Grade II-III) (Rs 0.8, p <0.05) and edema/infiltration area around of glioblastomas (Rs 0.5, p = 0, 02) were found and proved the evolutionary theory of glioma growth. Conclusion. The patterns of MET/FDG distribution as well as plastic and energy metabolism correlations in different tumor areas (core and edema/infiltration) and intact brain tissue in close vicinity to the tumor borders bring us closer to understanding the fundamental metabolic processes of brain gliomas.
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17th international conference on plasma-facing materials and components for fusion applications
(2020) Coenen, J.; Brezinsek, S.; Mateev, D.; Litnovsky, A.
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1D model of tokamak scrape-off layer and divertor plasmas: Dimensionless parameters and the results of numerical simulations
(2022) Krasheninnikov, S. I.; Kukushkin, A. S.
Solutions of a 1D model of the scrape-off layer and a divertor plasma in a tokamak are analyzed on the basis of dimensionless parameters governing the physics of both plasma and neutral transport and atomic physics processes. Numerical simulations based on fluid plasma and Monte Carlo neutral modeling confirm earlier results obtained with simplified analytic considerations and numerical simulations performed with fluid neutral description and demonstrate bifurcation of plasma parameters. These simulations also confirm that the major physical reasons for the rollover of the plasma flux to the target, which is the key feature of the phenomenon of divertor plasma detachment, are the impurity radiation loss and plasma recombination. It is suggested that simulations of the edge plasma based on dimensionless parameters provide a powerful tool for checking the consistency of the physics incorporated in existing complex 2D codes used for edge plasma modeling. Published under an exclusive license by AIP Publishing.
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1H MRS as a novel quantitative method for osteoporosis detection
(2020) Menshchikov, P. E.; Akhadov, T. A.; Ublinskiy, M. V.; Manzhurtsev, A. V.; Ivantsova, A. S.
© 2020 IOP Publishing Ltd.Bone mineral density is an important parameter that determines strength of the bone. Decrease in bone mineral density (BMD) leads to dangerous skeletal diseases like osteopenia, osteoporosis and an increased risk of fractures, for instance compression vertebral fracture (CVF). Dual-energy x-ray absorptiometry (DXA) and quantitative CT (QCT) are commonly accepted methods for assessing of the BMD. Previously FF was shown to increase in adult patients with osteoporosis as compared to healthy volunteers. The aim of the study was to explore the relationship between FF and BMD in children. Correlation analysis revealed significant inverse correlation link (p<0.05) between FF and BMD for all vertebrae of all patients (Fig.1C). The correlation suggests that the processes of increasing FF in the bone marrow and lowering the BMD are parallel in children. Therefore, 1H MRS could be good alternative to QCT and DXA without radiation dose in osteoporosis detection. Revealed significant negative correlation between FF and BMD in children without osteoporosis suggests that the processes of increasing FF in the bone marrow and lowering the BMD are parallel. Therefore, 1H MRS could be good alternative to QCT and DXA without radiation dose in osteoporosis detection.
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"2+1" Rhenium and Technetium Tricarbonyl Complexes with N,N′-Bidentate Ligands and Methyl 11-Isocyanoundecanoate
(2023) Miroslavov, A. E.; Sakhonenkova, A. P.; Tyupina, M. Yu.; Sidorenko, G. V.
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"2+1B" Technetium-99m Tricarbonyl Complexes with N,N'-Bidentate Ligands and Methyl 14-Isocyano-3-methyltetradecanoate
(2024) Miroslavov, A. E.; Tyupina,M.Yu.; Sakhonenkova,A.P.; Sidorenko,G.V.; Kochergina,A.R.
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"2+1B" Tricarbonyl Complexes of Technetium-99m and Rhenium with N,N '-Bidentate Ligands and Methyl 2-(Decylthio)-6-isocyanohexanoate
(2023) Miroslavov, A. E.; Sakhonenkova, A. P.; Tyupina, M. Yu.; Sidorenko, G. V.; Kochergina, A. R.
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2-D and 3-D numerical simulation of ferrite loaded coaxial transmission lines
(2020) Priputnev, P.; Romanchenko, I.; Pegel, I.; Tarakanov, V.
© 2020 IEEE.Coaxial transmission lines filled with saturated ferromagnetic material have been used for pulse sharpening purposes and high-frequency oscillation generation for a long time. These phenomena have been well studied experimentally, but have no exact analytical description; simplified models provide only qualitative agreement with the experiment. For quantitative description, it is necessary to solve Maxwell equations together with Landau-Lifshitz equation for the magnetization vector. The paper presents numerical simulation of high-voltage pulse sharpening process and excitation of high-frequency oscillations in coaxial lines filled with saturated ferrite. The modeling was performed using the KARAT code in three versions: axisymmetric (RZ) and three-dimensional Cartesian (XYZ) and cylindrical (\mathrm{R}\Theta\mathrm{Z}). The results are compared with previous experiments.
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2.56 Gbps CML transceiver for data concentrator ASIC
(2022) Atkin, E.; Serazetdinov, A.; Аткин, Эдуард Викторович; Серазетдинов, Артур Рафикович
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200 MeV LINEAR ELECTRON ACCELERATOR - PRE-INJECTOR FOR A NEW KURCHATOV SYNCHROTRON RADIATION SOURCE
(2021) Korchuganov, V. N.; Ushakov, V. A.; Ashanin, I. A.; Polozov, S. M.; Pronikov, A. I.; Rashchikov, V. I.; Ашанин, Илья Андреевич; Полозов, Сергей Маркович; Ращиков, Владимир Иванович
© 27th Russian Particle Accelerator Conference, RuPAC 2021. All rights reserved.New linear electron accelerator (linac) with an energy of about 200 MeV (or 300 MeV in a high-energy version) is being proposed for injection into the booster synchrotron, which is being developed for the reconstruction of the SIBERIA-2 accelerator complex with the aim of upgrade to 3rd generation source at the NRC «Kurchatov Institute». A modernized linac and its specific elements layout will described in the report. The modeling of accelerating structure and optimization of electrodynamics characteristics and fields distribution and geometric in order to reduce the beam spectrum at the output of the linac was done. A step-by-step front-to-end beam dynamics simulation results will discuss.
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27-day variation of galactic cosmic ray intensity by PAMELA experiment. Relationship with heliospheric parameters
(2019) Munini, R.; Modzelewska, R.; Mayorov, A.; Майоров, Андрей Георгиевич
© Published under licence by IOP Publishing Ltd. We analyzed the dynamics of the 27-day variation of galactic cosmic rays (GCR) using PAMELA data in the solar cycle 24 covering the period of 2006-2015. We studied the time line of the proton and helium spectra for different rigidities measured by PAMELA and compared with neutron monitor (NM) observations. We studied the relationship between the 27-day variations of GCR and heliospheric parameters: solar wind velocity and heliospheric magnetic field (HMF). We found that the 27-day variation observed by PAMELA was changing over the solar cycle 24. Near the solar minimum in the 2007-2008 it was observed the stationary 27-day variation with stable amplitude and time of maximum for almost ∼8 solar rotations. Solar wind velocity and Bx component of the HMF also showed the same clear 27-day periodicity. The recurrent changes of solar wind velocity were in strong antiphase with changes of GCR. In contrary in the rising phase of the solar cycle 24 the period of quasi-recurrent GCR variations was much more variable in time and in duration, in average 27-days, but also with the strong contamination of the higher harmonics. The antiphase relation between GCR and solar wind is not so clearly pronounced. Moreover, in the rising phase of the solar cycle 24 we established in all analyzed parameters some wave packages, periodically enhanced, taking place averagely each 1.5-2 years, suggesting the occurrence of the quasi biannual oscillations (QBOs).
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2D distributions of potential and density mean-values and oscillations in the ECRH and NBI plasmas at the TJ-II stellarator
(2022) Melnikov A. V.; Eliseev, L. G.; Drabinskiy, M. A.; Khabanov, P. O.; Мельников, Александр Владимирович
2D plasma potential φ distribution was measured in the electron cyclotron resonance heating (ECRH) and neutral beam injection (NBI) plasmas of the TJ-II stellarator with the heavy ion beam probe for the whole radial range and wide area of the poloidal angle, and supported by Langmuir probe data at the edge. The whole operation domain for the on-axis ECRH was explored (n¯e = 0.45-0.8 ×1019 m-3, P EC = 220-470 kW), in addition, NBI plasmas with n¯e = 0.9-1.3 × 1019 m-3 and P NBI = 510 kW were studied. In ECRH plasmas the density ramp-up is accompanied by the evolution of the potential from the bell-like to the Mexican hat profile, while the density profiles were flat or slightly hollow. The potential has the positive peak at the centre, and LFS-HFS (low field - high field sides) and up-down symmetry. Equipotential lines are consistent with vacuum magnetic flux surfaces. In the high-density NBI scenario, the φ profile was fully negative with a minimum up to -300 V at the centre, while at low-density ECRH plasma, φ has a maximum up to +0.9 kV at the centre. Fluctuations of potential and density are stronger in low-density scenarios and not poloidally symmetric. At the mid-radius (area of the maximum density), root mean square (RMS) of fluctuations were up to φ ∼15 V at LFS vs ∼20 V at HFS; RMS n e ∼2% at LFS vs ∼3% at HFS. In the NBI plasmas with the density rise, the asymmetry decreases and finally vanishing at n¯e = 1.2 × 1019 m-3. 2D distribution of the NBI-induced Alfvén eigenmodes (AEs) shows asymmetric ballooning structure: contrary to broadband turbulence, AE-associated potential perturbation dominates in the LFS with a factor up to 1.7 respect to the HFS. The electrostatic mode, excited in ECRH plasmas by suprathermal electrons also shows asymmetric structures: density perturbation dominates in the top-bottom direction compared to LFS-HFS direction. © 2022 IOP Publishing Ltd.
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2D MHD simulation of spontaneous magnetic fields generated during interaction of 1315.2-nm laser radiation with copper slabs at 1016 W/cm2
(2021) Jach, K.; Pisarczyk, T.; Stepniewski, W.; Swierczynski, R.; Kochetkov, I. U.; Кочетков, Юрий Владимирович
© 2021 Author(s).Multidimensional modeling of phenomena and processes occurring during the expansion of the laser-produced plasma for different irradiation conditions related to both the laser beam parameters and the target constructions is a very complex issue, especially when modeling requires consideration of kinetic processes associated with the development of various types of microscopic instability. Multidimensional PIC codes create such a possibility, but their use is limited to modeling phenomena even in a very narrow timescale due to the limited computational capabilities of current supercomputers. For this reason, the paper attempts to interpret the results of the spontaneous magnetic field (SMF) measurements obtained during the PALS (Prague Asterix Laser System) experiment [Pisarczyk et al., AIP Adv. 10, 115201 (2020); Pisarczyk et al., Phys. Plasmas 22, 102706 (2015)] based on the 2D magneto-hydrodynamic (MHD) model [Jach et al., Computer Modeling of Dynamic Interaction of Bodies by Free Point Method (PWN, Warsaw, 2011)]. The MHD equations were used with included arbitrary (i) current of hot electrons treating it as an additional external current and (ii) ion-sound instability responsible for the increase in anomalous resistance in areas with high temperature and low-density plasma. The spatial distribution of magnetic fields and current density obtained from 2D modeling are in acceptable agreement with the experimental results [Pisarczyk et al., Plasma Phys. Controlled Fusion 62, 115020 (2020); Zaraś-Szydłowska et al., AIP Adv. 10, 115201 (2020); Pisarczyk et al., Phys. Plasmas 22, 102706 (2015)]. The inclusion of temporal changes in anomalous resistance in modeling allowed us to explain the persistence of high SMF amplitude at the level of several megagauss after the laser pulse ended due to the effect of magnetic field freezing.
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2D Numerical Simulation of Adiabatic Shear Bands Formation
(2022) Muratov, R. V.; Ryabov, P. N.; Soukharev, M. B.; Муратов, Родион Владимирович; Рябов, Павел Николаевич; Сухарев, Михаил Борисович
© 2022 American Institute of Physics Inc.. All rights reserved.In this work we suggest a mathematical model of motion of the elastoplastic materials with nonlinear plasticity constitutive law. We also propose an effective numerical method based on the Godunov-type scheme for simulation of such tasks on two-dimensional eulerian meshes. We test the proposed method on a benchmark problem that includes formation of the single adiabatic shear band (A S B) due to initial temperature perturbation. Then we study the formation of multiple adiabatic shear bands at high-speed shear deformation.
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2nd Comment on "On the Klein–Gordon oscillator in topologically charged Ellis–Bronnikov type wormhole spacetime"
(2024) Bronnikov, K. A.; Бронников, Кирилл Александрович
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(2 + 1)-dimensional Boiti–Leon–Pempinelli equation – Domain walls, invariance properties and conservation laws
(2020) Wang, G.; Vega-Guzman, J.; Kamis, Alzahrani, A.; Kara, A. H.; Biswas, A.
© 2020 Elsevier B.V.We analyze domain wall type solutions, symmetry/invariance properties and conservation laws of the (2+1)-dimensional Boiti–Leon–Pempinelli system which describes the evolution of the horizontal velocity component of water waves propagating in two directions. It turns out that the equation is extensive in these properties. Some domain wall properties are also investigated.
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3-D Coupled simulation of a VVER 1000 with PARCS/ATHLET
(2020) Henry, R.; Perin, Y.; Velkov, K.; Nikonov, S. P.
© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).A new OECD/NEA benchmark entitled “Reactivity compensation with diluted boron by stepwise insertion of control rod cluster” is starting. This benchmark, based on high quality measurements performed at the NPP Rostov Unit 2, aims to validate and assess high fidelity multi-physics simulation code capabilities. The Benchmark is divided in two phases: assembly wise and pin-by-pin resolution of steady-state and transient multi-physics problems. Multi-physics simulation requires the generation of parametrized few-group cross-sections. This task used to be done with deterministic (2-D) lattice codes, but in the past few years the Monte-Carlo code SERPENT has demonstrate its ability to generate accurate few-group homogenized cross-section without approximations, neither on the geometry nor in the nuclear data. Since the whole core SERPENT models for production of such cross-section libraries would be computationally costly (and the standard 2-D approach may introduce unnecessary large approximations), 3-D models of each assembly type in infinite radial lattice configurations have been created. These cross-sections are then used to evaluate effective multiplication factors for different core configurations with the diffusion code PARCS. The results are compared with the reference SERPENT calculations. In the next step, a thermal-hydraulic model with the system code ATHLET applying an assembly-wise description of the core (i.e. one channel per fuel assembly) has been developed for coupled PARCS/ATHLET transient test calculations. This paper describes in detail the models and techniques used for the generation of the few-group parameterized cross section libraries, the PARCS model and the ATHLET model. Additionally, a simple exercise with coupled code system PARCS/ATHLET is presented and analysed.
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3-D Numerical Modeling of MHD Flows in an Aluminum Reduction Cell
(2019) Pianykh, A. A.; Tkacheva, O. Y.; Radzyuk, A. Y.; Bogovalov, S. V.; Tronin, I. V.; Боговалов, Сергей Владимирович; Тронин, Иван Владимирович
© 2019 IOP Publishing Ltd. All rights reserved.Three-dimensional numerical modeling of processes in an aluminum electrolytic cell at a current of 9 kA is performed. The model considers the nonlinear temperature dependence of all physical characteristics of materials. The specificity of the work is the inclusion in the model of the dynamics of the gas formed during the operation of the cell. The bubble motion, magnetic forces and heat convection essentially affect the overall dynamics of the electrolyte and metal. Calculations were carried out using the commercial software packages ANSYS CFX 18.2 and ANSYS Maxwell united with the aid of the user FORTRAN program.
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3-HYDROXYPYRIDINE DERIVATIVE WITH ASCORBIC ACID RESIDUE INCREASES SURVIVAL OF CEREBRAL CORTEX CELLS UNDER CONDITIONS OF EXPERIMENTAL ISCHEMIA IÐIECAIAIIA 3-AEAÐIENEIEÐEAEIA N INOAOEII ANEIÐAEIIAIE EENEIOU IIAUØAAO AUÆEAAAIINOU EEAOIE AIEIAIIAI IICAA A ONEIAEßO YENIAÐEIAIOAEUIIE EØAIEE
(2023) Blinova, E. V.; Timoshkin, D. E.; Belanov, K. Y.; Vasilkina, O. V.; Блинова, Екатерина Валериевна