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Tytuł:
Modelling of new generation plasma optical devices
Autorzy:
Litovko, I. V.
Goncharov, A. A.
Dobrovolskiy, A. N.
Naiko, L. V.
Naiko, I. V.
Powiązania:
https://bibliotekanauki.pl/articles/971496.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
anode layer
plasma lens
plasma accelerator
plasma jet
space charge
Opis:
The paper presents new generation plasma optical devices based on the electrostatic plasma lens configuration that opens a novel attractive possibility for effective high-tech practical applications. Original approaches to use of plasma accelerators with closed electron drift and open walls for the creation of a cost-effective low-maintenance plasma lens with positive space charge and possible application for low-cost, low-energy rocket engine are described. The preliminary experimental, theoretical and simulation results are presented. It is noted that the presented plasma devices are attractive for many different applications in the state-of-the-art vacuum-plasma processing.
Źródło:
Nukleonika; 2016, 61, 2; 207-212
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mössbauer study of treated Nd2Fe14B
Autorzy:
Budzyński, M.
Constantin, V. C.
Popescu, A.-N. J.
Surowiec, Z.
Tkachenka, T. M.
Yanushkevich, K. I.
Powiązania:
https://bibliotekanauki.pl/articles/146270.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
intermetallics
intergranular corrosion
Mössbauer spectroscopy
Opis:
The Nd2Fe14B cylindrical magnets were treated with water solutions of alkali, acid, and salt. Mössbauer spectroscopy was applied to study the composition and properties of the surface material of the treated magnets. It is shown that the main phase of the permanent Nd2Fe14B magnet partly decomposes. The released α-Nd at the grain boundaries interacts with water and forms neodymium hydroxide matrix, and the released Fe diffuses into it. The presence of Fe-Nd(OH)3 is refl ected in the paramagnet doublet in the Mössbauer spectra of treated neodymium magnets.
Źródło:
Nukleonika; 2015, 60, 1; 7-10
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of the behavior of in - vessel mirrors for ITER with ECR plasma discharges
Autorzy:
Voitsenya, V. S.
Bardamid, A. F.
Belyaeva, A. I.
Bondarenko, V. N.
Davis, J. W.
Konovalov, V. G.
Mukhin, E. E.
Razdobarin, A. G
Ryzhkov, I. V.
Shapoval, A. N.
Shtan, A. F.
Skoryk, O. A.
Solodovchenko, S. I.
Powiązania:
https://bibliotekanauki.pl/articles/147820.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
ECR plasma
mirrors for plasma diagnostics in ITER
structure
sputtering
chemical erosion
Opis:
The main experimental results related to the problems associated with in-vessel mirrors in ITER obtained with the DSM-2 facility at the Kharkov Institute of Plasma Physics over the past few years are described and discussed. Mirrors made from various polycrystalline (Be, Al, SS, Cu, Mo, Ta, W) and single crystal (Ni, SS, Mo, W) metals, metal films (Be, Cu, Mo, Rh) on different metal substrates (V, SS, Cu, Mo), and an amorphous alloy (ZrTiCuNiBe) have been studied. In addition, the behavior of protective oxide coatings under plasma bombardment has also been analyzed.
Źródło:
Nukleonika; 2012, 57, 2; 157-162
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the radiocesium behavior in a small humic lake (Lithuania)
Autorzy:
Tarasiuk, N.
Moisejenkova, A.
Koviazina, E.
Karpicz, R.
Astrauskiene, N.
Powiązania:
https://bibliotekanauki.pl/articles/148132.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radiocesium
lake
closed
humic
sediment
tench
Opis:
Peculiarities of radiocesium contamination of a small humic lake, which became meromictic some thirty-five years ago due to the inflow of a large amount of humic water, are presented. The lake consists of two separate water layers, which do not intermix. A lower water layer of the lake below some 3-m depth is stagnant and anaerobic, and radiocesium load of the sediments is mainly caused by nuclear weapons fallout. The radiocesium load of the sediments of the upper monomictic water layer is significantly larger due to additional contamination after the Chernobyl accident. Radiocesium activity concentrations in lake water increase with depth, and even in the surface layer, they are commonly the largest among the neighboring lakes with transparent water. It is shown that bottom areas of the monomictic part of the lake with the elevated radiocesium deepening into sediments are related to the favorite sites of the tench (Tinca tinca) winter torpor. Sediment bioturbation and redistribution due to tench activities distort naturally formed radiocesium vertical profiles and they cannot be used for estimations of sedimentation rates and sediment chronology. The studied lake can be useful as an analogous model in analyzing structural and radiological consequences of humic water inflows to closed lakes. Concerning extreme radiological situations in closed humic lakes related to their specific vertical structure, they may be treated as critical objects in assessing the risk to humans after radionuclide deposition events.
Źródło:
Nukleonika; 2009, 54, 3; 211-220
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of warmness and spatial nonuniformity of plasma waveguide on periodic absolute parametric instability
Autorzy:
Zaki, N. G.
Bekheit, A. H.
Powiązania:
https://bibliotekanauki.pl/articles/147605.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
periodic absolute parametric instability (API)
low frequency waves
warm plasma
growth rate
dispersion equation
Opis:
The periodic absolute parametric instability (API) of the low-frequency oscillations excited by a monochromatic pumping field of an arbitrary amplitude in a warm 1-D (one-dimensional) nonuniform magnetoactive plasma is investigated. The separation method can be used for solving the two-fluid plasma equations describing the system. By applying this method we were able to determine the frequencies and growth rates of unstable modes and the self-consistent electric field. Plasma electrons are considered to have a thermal velocity. Different solutions for the spatial equation can be obtained the following cases: A) API in a uniform plasma, B) API in a nonuniform plasma. The latter has been studied here for two cases: B.1) the exact harmonic oscillator and B.2) the bounded harmonic oscillator (a bounded plasma). An increment has been found in the build-up of the oscillations, and it has been shown that the spatial nonuniformity of the plasma exerts the stabilizing effect on the parametric instability. A reduced growth rate of API in the warm plasma, in comparison to the cold plasma, is reported. It has also been found that the warmness of the plasma has no effect on the solution of the space part of the problem (only through the separation constant).
Źródło:
Nukleonika; 2011, 56, 4; 305-309
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo calculation of scattered radiation from applicators in low energy clinical electron beams
Autorzy:
Jabbari, N.
Hashemi-Malayeri, B.
Farajollahi, A. R.
Kazemnejad, A.
Powiązania:
https://bibliotekanauki.pl/articles/147627.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Monte Carlo
radiation therapy
medical linear accelerator
electron applicator
scattered radiation
treatment planning
Opis:
. In radiotherapy with electron beams, scattered radiation from an electron applicator influences the dose distribution in the patient. The contribution of this radiation to the patient dose is significant, even in modern accelerators. In most of radiotherapy treatment planning systems, this component is not explicitly included. In addition, the scattered radiation produced by applicators varies based on the applicator design as well as the field size and distance from the applicators. The aim of this study was to calculate the amount of scattered dose contribution from applicators. We also tried to provide an extensive set of calculated data that could be used as input or benchmark data for advanced treatment planning systems that use Monte Carlo algorithms for dose distribution calculations. Electron beams produced by a NEPTUN 10PC medical linac were modeled using the BEAMnrc system. Central axis depth dose curves of the electron beams were measured and calculated, with and without the applicators in place, for different field sizes and energies. The scattered radiation from the applicators was determined by subtracting the central axis depth dose curves obtained without the applicators from that with the applicator. The results of this study indicated that the scattered radiation from the electron applicators of the NEPTUN 10PC is significant and cannot be neglected in advanced treatment planning systems. Furthermore, our results showed that the scattered radiation depends on the field size and decreases almost linearly with depth.
Źródło:
Nukleonika; 2007, 52, 3; 97-103
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plutonium and americium in sediments of Lithuanian lakes
Autorzy:
Remeikis, V.
Gvozdaite, R.
Druteikiene, R.
Plukis, A.
Tarasiuk, N.
Špirkauskaite, N.
Powiązania:
https://bibliotekanauki.pl/articles/148886.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plutonium isotopes
americium
sediments
isotopic composition
Opis:
The assessment of contribution of the global and the Chernobyl NPP (Nuclear Power Plant) accident plutonium and americium to plutonium pollution in sediments of Lithuanian lakes is presented. Theoretical evaluation of activity ratios of 238Pu/239+240Pu and 241Pu/239+240Pu in the reactor of unit 4 of the Chernobyl NPP before the accident was performed by means of the ORIGEN-ARP code from the SCALE 4.4A program package. Non-uniform distribution of radionuclides in depositions on the Lithuanian territory after nuclear weapon tests and the Chernobyl NPP accident is experimentally observed by measuring the lake sediment pollution with actinides. The activity concentration of sediments polluted with plutonium ranges from 2.0 š 0.5 Bq/kg d.w. (dry weight) in Lake Asave . lis to 14 š 2 Bq/kg d.w. in Lake Juodis. The ratio of activity concentrations of plutonium isotopes 238Pu/239+240Pu measured by á-spectrometry in the 10-cm-thick upper layer of bottom sediment varies from 0.03 in Lake Juodis to 0.3 in Lake Žuvintas. The analysis of the ratio values shows that the deposition of the Chernobyl origin plutonium is prevailing in southern and south-western regions of Lithuania. Plutonium of nuclear weapon tests origin in sediments of lakes is observed on the whole territory of Lithuania, and it is especially distinct in central Lithuania. The americium activity due to 241Pu decay after the Chernobyl NPP accident and global depositions in bottom sediments of Lithuanian lakes has been evaluated to be from 0.9 to 5.7 Bq/kg.
Źródło:
Nukleonika; 2005, 50, 2; 61-66
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of uranium concentrations in some building materials in Iraq
Autorzy:
Najam, L. A.
Tawfiq, N. F.
Yassen, Q. A.
Powiązania:
https://bibliotekanauki.pl/articles/148408.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
uranium concentration
fission tracks
CR-39 track detectors
building materials
Opis:
Eleven commonly used building construction materials were collected from several origins in Iraq and analyzed for uranium concentration using a fission track technique. The results of measurements of uranium concentration ranged between 0.22 ppm in ceramics and 1.86 ppm in marble. The obtained results were well below the allowed limit of 11.7 ppm.
Źródło:
Nukleonika; 2013, 58, 2; 329-331
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of initial recombination of ions created in quasi-pulsed radiation fields
Autorzy:
Zielczyński, M.
Golnik, N.
Gryziński, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/146942.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
initial recombination
volume recombination
ionization chambers
pulse radiation
Opis:
A new method is proposed for the determination of ion collection efficiency due to initial recombination process only, in a high pressure ionization chamber, operating in a quasi-pulsed radiation field. It is shown that the influence of undesirable volume recombination can be eliminated using a semi-empirical formula. The unknown function of the chamber polarizing voltage, included to the formula, can be found experimentally in the investigated radiation field, using the approach proposed in the paper. The function is the same for all radiation fields with similar time structure.
Źródło:
Nukleonika; 2008, 53, suppl. 2; 33-36
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Slow positron beam at the JINR, Dubna
Autorzy:
Horodek, P.
Kobets, A. G.
Meshkov, I. N.
Sidorin, A. A.
Orlov, O. S.
Powiązania:
https://bibliotekanauki.pl/articles/147134.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
positron beam
positron injector
Opis:
The Low Energy Positron Toroidal Accumulator (LEPTA) at the Joint Institute for Nuclear Research (JINR) proposed for generation of positronium in flight has been adopted for positron annihilation spectroscopy (PAS). The positron injector generates continuous slow positron beam with positron energy range between 50 eV and 35 keV. The radioactive 22Na isotope is used. In distinction to popular tungsten foil, here the solid neon is used as moderator. It allows to obtain the beam intensity of about 105 e+/s width energy spectrum characterized by full width at half maximum (FWHM) of 3.4 eV and a tail to lower energies of about 30 eV. The paper covers the characteristic of variable energy positron beam at the LEPTA facility: parameters, the rule of moderation, scheme of injector, and transportation of positrons into the sample chamber. Recent status of the project and its development in the field of PAS is discussed. As an example, the measurement of the positron diffusion length in pure iron is demonstrated.
Źródło:
Nukleonika; 2015, 60, No. 4, part 1; 725-728
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carbon-13 fractionation in the oxidation of propionate of natural isotopic composition with permanganate and manganate
Autorzy:
Zieliński, M.
Fry, A.
Zielińska, A.
Ogrinc, N.
Papiernik-Zielińska, H.
Kobal, I.
Powiązania:
https://bibliotekanauki.pl/articles/146720.pdf
Data publikacji:
2000
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
carbon-13
carbon-14
fractionation
manganate
oxidation
permanganate
propionate
Opis:
Carbon-13 fractionation in the oxidation of sodium propionate of natural isotopic composition with permanganate in water solution and with manganate in alkaline solution has been investigated and compared with carbon-14 kinetic isotope effects in the oxidation of (3-14C) – and (2-14C) propionate with permanganate. The experimental carbon-13 isotope ratios, R(13C/12C)cumul., corrected for dilution of R(13C/12C)a by carbon dioxide derived from all external sources and by carbon dioxide derived from (C-1) and from (C-3) of propionate at its complete and partial oxidations, used for calculation of 13C alfa KIE, provided the carbon-13 isotope effects corresponding to initial oxidation of alpha carbon, which correlate well with (2-14C) KIE determined previously, (k12/k13 -1)?100 ? 1/2(k12/k14 -1)?100 ? 1/2(4.6š0.3) at 373 K. The possibility of extension of isotope ratio measurements, using modern double collector mass spectrometers, from geochemical, biomedical, agriculture and environmental research to carbon-13 isotope effects studies in chemical organic reactions is briefly discussed.
Źródło:
Nukleonika; 2000, 45, 4; 221-224
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First beam from the DECRIS 14-2m ion source for Slovak Republic
Autorzy:
Loginov, V.
Bekhterev, V.
Bogomolov, S.
Efremov, A.
Lebedev, A.
Leporis, M.
Yazvitsky, N.
Zelenak, A.
Powiązania:
https://bibliotekanauki.pl/articles/148668.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
ECR ion source
injector
Opis:
The ECR laboratory of the Cyclotron Centrum of Slovak Republic (CC SR) in Bratislava, Slovakia, consists of the DECRIS 14-2m ion source and two low energy channels. It is a complete injector, consisting of an ECR ion source, focusing and steering elements, an analyzing magnet, a vacuum system, and an ion beam diagnostic system. The DECRIS 14-2m ion source is a multiply charged heavy ion source based on the electron cyclotron resonance principle. The ECR ion source DECRIS 14-2m and other system have been designed and manufactured at the FLNR JINR. The preliminary testing (magnetic field measurements, vacuum testing and testing of ECR ion source) has been performed at FLNR JINR. The final assembly of the DECRIS 14-2m will be done at the CC SR in Bratislava.
Źródło:
Nukleonika; 2003, 48,suppl.2; 85-88
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control of the propagation of intense laser pulses in gas for laser plasma acceleration
Autorzy:
Giulietti, D.
Cecchetti, C. A.
Drenska, N. V.
Faccini, N.
Gatti, C.
Gatti, G.
Giulietti, A.
Gizzi, L.
Labate, L.
Levato, T.
Martellotti, S.
Pathak, N.
Valente, P.
Powiązania:
https://bibliotekanauki.pl/articles/147890.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
intense laser pulses
ultra-short laser pulse
laser plasma
plasma acceleration
Opis:
The role of the propagation mechanisms of intense and ultra-short laser pulses in gas is presented, as well as the first results of the laser plasma acceleration (LPA) tests at Frascati National Laboratories (INFN), in the frame of NTA-PLASMONX project.
Źródło:
Nukleonika; 2012, 57, 2; 221-225
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Void fraction and flow regime determination by means of MCNP code and neural network
Autorzy:
Rabiei, A.
Shamsaei, M.
Kafaee, M.
Shafaei, M.
Mahdavi, N.
Powiązania:
https://bibliotekanauki.pl/articles/146656.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
flow regime
gamma-ray densitometry
neural network (NN)
Monte Carlo N-particle (MCNP)
void fraction
Opis:
One of the non-intrusive and accurate methods of measuring void fraction in two-phase gas liquid pipe flows is the use of the gamma-transmission void fraction measurement technique. The goal of this study is to describe low-energy gamma-ray densitometry using an 241Am source for the determination of void fraction and flow regime in water/gas pipes. The MCNP code was utilized to simulate electron and photon transport through materials with various geometries. Then, a neural network was used to convert multi-beam gamma-ray spectra into a classification of the flow regime and void fraction. The simulations cover the full range of void fraction with Bubbly, Annular and Droplet flows. By using simulation data as input to the neural networks, the void fraction was determined with an error less than 3% regardless of the flow regime. It has thus been shown that multi-beam gamma-ray densitometers with a detector response examined by neural networks can analyze a two-phase flow with high accuracy.
Źródło:
Nukleonika; 2012, 57, 3; 345-349
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of thermal hydraulics in a KAROLINA calorimeter for its calibration methodology validation
Autorzy:
Luks, A.
Pytel, K.
Tarchalski, M.
Uzunow, N.
Krok, T.
Powiązania:
https://bibliotekanauki.pl/articles/147579.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
computional fluid dynamics
CFD
differential calorimeter
gamma heating
gamma rays
Jules Horowitz Reactor
JHR
modelling of thermal hydraulics
nuclear heating
nuclear reactor
research
reactor MARIA
Opis:
Results of numerical calculations of heat exchange in a nuclear heating detector for nuclear reactors are presented in this paper. The gamma radiation is generated in nuclear reactor during fission and radiative capture reactions as well as radioactive decay of its products. A single-cell calorimeter has been designed for application in the MARIA research reactor in the National Centre for Nuclear Research (NCBJ) in Świerk near Warsaw, Poland, and can also be used in the Jules Horowitz Reactor (JHR), which is under construction in the research centre in Cadarache, France. It consists of a cylindrical sample, which is surrounded by a gas layer, contained in a cylindrical housing. Additional calculations had to be performed before its insertion into the reactor. Within this analysis, modern computational fuid dynamics (CFD) methods have been used for assessing important parameters, for example, mean surface temperature, mean volume temperature, and maximum sample (calorimeter core) temperature. Results of an experiment performed at a dedicated out-of-pile calibration bench and results of numerical modelling validation are also included in this paper.
Źródło:
Nukleonika; 2016, 61, 4; 453-460
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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