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Wyszukujesz frazę "ions" wg kryterium: Wszystkie pola


Tytuł:
Influence of diaphragms on measurements of ions emitted from dense magnetized plasmas
Autorzy:
Skladnik-Sadowska, E.
Sadowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/146562.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
diagnostic of ions
energy distribution
plasma discharges
separate ions
Opis:
The paper concerns the diagnostics of ions escaping from dense magnetized plasma (DMP) discharges. Particular attention is paid to the basic problem of the separation of such ions from the investigated plasma, under the condition that this process should not disturb the velocity (and energy) distribution functions of the measured ions.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 57-60
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production of negative hydrogen ions using a low-pressure reflex discharge source
Autorzy:
Toader, E.
Powiązania:
https://bibliotekanauki.pl/articles/147442.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
magnetized plasma
negative ions
plasma sources
Opis:
In this paper we analyze the possibility to use the reflex discharge plasma as a volume source of negative hydrogen ions. The basic internal parameters like the temperature Te and the density ne of the electrons, the density ni of the positive hydrogen ions, the density n- of the negative hydrogen ions, and the negative ion fraction n-/ne are measured and discussed. The operating conditions are optimized within the pressure range 0.1-10 Pa, the discharge power 20-140 watt, and the magnetic field 0-150 gauss. The experiment shows that the enhanced magnetic ionization is the most effective within the pressure range from 0.7 to 4.0 Pa. When p ť 1 Pa the cold electron temperature Te is 0.77 eV, the cold electron density ne is 4.2 ´ 10 18 m-3 and the negative ion density n- is as high as 0.8 x 10 17 m-3. The negative ion fraction n-/ne increases from 1.4% for p = 0.1 Pa to almost 2.2% within the pressure range 1-4 Pa. The positive ion density scales with the power, while the negative ion density and the negative ion fraction seems to saturate at higher power levels.
Źródło:
Nukleonika; 2006, 51, 1; 29-35
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Position of Fe ions in MgO crystalline structure
Autorzy:
Szczerba, J.
Prorok, R.
Stoch, P.
Śnieżek, E.
Jastrzębska, I.
Powiązania:
https://bibliotekanauki.pl/articles/146372.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Mössbauer spectroscopy
MgO
Fe ions
crystal structure
Opis:
Magnesium oxide (MgO) is one of the most important raw materials in many branches of industry. Magnesium oxide is a popular refractory raw material because of its high refractoriness and high resistance to basic slags and environment. In many cases, use of MgO is limited by its properties, especially the presence of secondary phases like iron oxides. The amount and distribution of iron oxides can strongly infl uence the technological properties of MgO and depend on the manufacturing method, particularly the heat-treatment process. The aim of the study was to evaluate the infl uence of the heat-treatment process on amount and distribution of iron ions in a magnesium oxide lattice. The 57Fe Mössbauer effect measurements of fused and sintered magnesium oxide samples doped by the iron oxide were conducted. Investigation reveals in both cases the presence of Fe2+ as well as Fe3+ ions. Fe2+ ions occupy Mg2+ octahedral sites in the MgO lattice, whereas the Fe3+ ions are located in highly distorted octahedral coordination. The amount of Fe2+ varies from around 66% for fused samples to 30% for sintered samples.
Źródło:
Nukleonika; 2015, 60, 1; 143-145
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient induced molecular negative ions formed in cold electron collisions with polarized molecules
Autorzy:
Toader, E. I.
Graham, W. G.
Powiązania:
https://bibliotekanauki.pl/articles/147748.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
interaction processes in plasmas
new negative molecular ions
Opis:
Using a relatively simple semiclassical model, it is shown that transient, induced molecular negative ions (TIMNI), are produced through a potential barrier interaction between cold electron collisions and polarizable molecules in plasma. Such new negative ions lead to radio-frequency absorption in such discharges. The calculated radio-frequency absorption frequencies are consistent with earlier experimental measurements.
Źródło:
Nukleonika; 2008, 53, 3; 123-126
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of instruments of nuclear physics to the calculation of theoretical dose distributions in various organs of the human body for beams used in hadrontherapy
Autorzy:
Maliszewska, W.
Sękowski, P.
Skwira-Chalot, I.
Powiązania:
https://bibliotekanauki.pl/articles/146972.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
carbon ions
hadrontherapy
hydrogen ions
SRIM
Xeloss
Opis:
The area of interests of nuclear physics are studies of reactions, wherein atomic nuclei of projectile collide with target nuclei. An amount of energy lost by projectile nucleus during its passing through the target is a major issue – it is important to know how charged particles interact with matter. It is possible to afford this knowledge by using theoretical programs that calculate energy loss applying the Bethe-Bloch equation. Hadrontherapy, which is a field of still growing interest, is based on the interactions of charged particles with matter. Therefore, there exists a need of creating a simple model that could be used to the calculation of dose distributions in biological matter. Two programs (SRIM, Xeloss), used to the calculation of energy loss by nuclear physicist, have been adapted to determine the dose distributions in analogues of human tissues. Results of the calculations with those programs for beams used in hadrontherapy (e.g. 1H, 12C) will be compared with experimental data available in references.
Źródło:
Nukleonika; 2016, 61, 1; 19-22
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Systematic study of directed flow at RHIC energies
Autorzy:
Mignerey, A.
Powiązania:
https://bibliotekanauki.pl/articles/148368.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
relativistic heavy ions
directed flow
PHOBOS
charged hadrons
Opis:
Directed flow, v1, of charged hadrons has been measured in Au-Au collisions at RHIC for center-of-mass energies square root(sNN) = 19.6, 130, 62.4, and 200 GeV using the PHOBOS detector. The large acceptance of PHOBOS for charged particles allows measurements over the full range of pseudorapidity |eta| < 5.4. The results for a symmetric subevent method are shown at all four energies. Comparison is made to a mixed harmonic method for the highest energy, and compared to similar results from the STAR collaboration.
Źródło:
Nukleonika; 2006, 51,suppl.3; 29-31
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ionic processes in irradiated solid polymers
Autorzy:
Szadkowska-Nicze, M.
Powiązania:
https://bibliotekanauki.pl/articles/147854.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
irradiated polymers
radical ions
ion recombination
radiothermoluminescence
relaxation in polymers
Opis:
The reactions of ionic species generated in irradiated polymers (polyethylene, poly(dimethylsiloxane), poly(methyl methacrylate), and poly(ethylene terephthalate)) doped with pyrene, Py, were observed by radiothermoluminescence and complementary absorption spectroscopic measurements. The charge stabilization in polymers and charge transfer to the solute depend on the chemical structure of polymer chains and physical state of the polymer matrix. The recombination of ionic species is stimulated by relaxation processes of polymers. Total neutralization of charges in irradiated polymers occurs at the glass transition temperature of polymers. Mutual recombination of Py radical ions generates singlet excited states of the solute followed by Py monomer and excimer (depending on the solute concentration) fluorescence. Recombination of Py radical cations and negative species from the polymer matrix leads to the formation of Py triplet excited states followed by Py phosphorescence.
Źródło:
Nukleonika; 2005, 50,suppl.2; 45-49
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of EMR data for Fe2+(S=2) ions in a [2Fe-2S] cluster in the reduced ferredoxin
Autorzy:
Rudowicz, Cz.
Piwowarska, D.
Gnutek, P.
Powiązania:
https://bibliotekanauki.pl/articles/146266.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
[2Fe-2S] cluster
electron magnetic resonance (EMR)
Fe2+ ions
microscopic spin Hamiltonian (MSH)
zero field splitting (ZFS) parameters
Opis:
The modelling techniques employed in this study utilize structural data to enable correlation of EMR data – described by the spin Hamiltonian (SH) and optical spectroscopy data – described by the crystal field (CF) Hamiltonian. These techniques enable also to predict magnetic and spectroscopic properties of 3dN ions, especially 3d4 and 3d6 ions, in various systems. Specific applications are considered for [Fe2+ and Fe3+] binuclear centres in [2Fe-2S] cluster in the reduced ferredoxin and related biological molecules. The background for model calculations of the zero-field splitting (ZFS) parameters and/or crystal field parameters and the capabilities of the two major techniques used will be presented in the full paper. Here, we present preliminary results of the microscopic spin Hamiltonian (MSH) modelling for Fe2+ (3d6) ions in the reduced ferredoxin.
Źródło:
Nukleonika; 2013, 58, 3; 347-350
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Superconducting Cyclotron as a primary accelerator for exotic beam facilities
Autorzy:
Maggiore, M.
Rifuggiato, D.
Calabretta, L.
Powiązania:
https://bibliotekanauki.pl/articles/146203.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
cyclotron
ions
medical
superconducting
Opis:
A four sector compact superconducting cyclotron for light ion beams with a maximum energy of 250 MeV/amu has been studied. This cyclotron is mainly designed to accelerate H2 + ions to be extracted by stripping. Ions like C, O or Ne can also be accelerated and extracted by stripping. Extraction by stripping allows to overcome many problems, especially if a certain beam intensity is requested. The preliminary design model of the magnet circuit has been accomplished with the 3D electromagnetic code OPERA [4]. The design of the main coils and of the cryostat has been investigated, too. The features of beam dynamics of this cyclotron, including extraction trajectories, will be presented. Several fields of application have been envisaged for this cyclotron, namely nuclear physics, therapy treatment, interdisciplinary research and radioisotope production using low or medium intensity beams.
Źródło:
Nukleonika; 2003, 48,suppl.2; 165-167
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Initial recombination of ions in ionization chambers filled with hydrocarbon gases
Autorzy:
Gryziński, M.
Golnik, N.
Zielczyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/148268.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
initial recombination
ionization chambers
Opis:
Data on the initial recombination of ions are needed for designing recombination chambers, used in mixed radiation dosimetry in order to obtain information about radiation quality. Nevertheless, experimental data for pressurized gases are scarce, whereas reliable theoretical models are absent. The paper provides experimental data on the initial recombination in hydrocarbon gases (methane, ethane and propane) depending on gas pressure up to 1.8 MPa. The data were derived from the measurements of saturation curves of a tissue equivalent recombination chamber of an REM-2 type, in reference radiation fields of 137Cs and 239Pu-Be sources. Ion recombination due to volume recombination and back diffusion of ions was subtracted from the measured values of ion collection efficiency. The values of gas parameters needed for the subtraction procedure were determined by measurements of saturation curves of the chamber at several dose rates for each gas pressure. The important practical rule resulting from the experiments is that in the first approximation the initial recombination does not depend on the kind of the hydrocarbon gas but only on its density in the chamber.
Źródło:
Nukleonika; 2007, 52, 1; 7-12
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected methods of electronand ion-diagnostics in tokamak scrape-off-layer
Autorzy:
Sadowski, M. J.
Powiązania:
https://bibliotekanauki.pl/articles/146123.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
diagnostics
electrons
ions
fusion products
probes
tokamak
Opis:
This invited paper considers reasons why exact measurements of fast electron and ion losses in tokamaks, and particularly i n a scrape-off-layer and near a divertor region, are necessary in order to master nuclear fusion energy production. Attention is also paid to direct measurements of escaping fusion products from D-D and D-T reactions, and in particular of fast alphas which might be used for plasma heating. The second part describes the generation of so-called runaway and ripple-born electrons which might induce high energy losses and cause severe damages of internal walls in fusion facilities. Advantages and disadvantages of different diagnostic methods applied for studies of such fast electrons are discussed. Particular attention is paid to development of a direct measuring technique based on the Cherenkov effect which might be induced by fast electrons in appropriate radiators. There are presented various versions of Cherenkov-type probes which have been developed by the NCBJ team and applied in different tokamak experiments. The third part is devoted to direct measurements of fast ions (including those produced by the nuclear fusion reactions) which can escape from a high-temperature plasma region. Investigation of fast fusion-produced protons from tokamak discharges is reported. New ion probes, which were developed by the NCBJ team, are also presented. For the fi rst time there is given a detailed description of an ion pinhole camera, which enables irradiation of several nuclear track detectors during a single tokamak discharge, and a miniature Thomson-type mass-spectrometer, which can be used for ion measurements at plasma borders.
Źródło:
Nukleonika; 2015, 60, 2; 199-206
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Higher - order field - dependent terms in spin Hamiltonians for transition ions : implications for high - magnetic field and high - frequency EMR measurements
Autorzy:
Rudowicz, Cz.
Powiązania:
https://bibliotekanauki.pl/articles/148384.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron magnetic resonance (EMR)
high-magnetic field and high-frequency EMR (HMF-EMR)
generalized spin Hamiltonians (GSH)
higher-order field-dependent (HOFD) terms
zero-field splitting (ZFS) terms
transition ions in crystals
Opis:
An overview of theoretical background of the higher-order field-dependent (HOFD) terms in the generalized spin Hamiltonians for transition ions and current status of experimental studies of the HOFD terms is provided in the nutshell. The terms nonlinear in the magnetic field (B) of the type: B2S2, B3S, B5S or B2I2, B3I, B5I, where S and I is the electronic and nuclear spin, respectively, are of particular importance as compared with the usual linear Zeeman term B.g.S. This is due to the high B values, up to 100 T (pulsed fields), achievable at present in the high-magnetic field and/ or high-frequency electron magnetic resonance (HMF-EMR) measurements of magnetic and spectroscopic properties. A blueprint for future theoretical and experimental studies of the HOFD terms is proposed taking into account their implications for HMF-EMR measurements
Źródło:
Nukleonika; 2013, 58, 3; 341-345
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Damage distributions in GaAs single crystal irradiated with 84Kr (394 MeV), 209Bi (710 MeV) and 238U (1300 MeV) swift ions
Autorzy:
Didyk, A. Y.
Komarov, F. F.
Vlasukova, L. A.
Gracheva, E. A.
Hofman, A.
Yuvchenko, V. N.
Wiśniewski, R.
Wilczyńska, T.
Powiązania:
https://bibliotekanauki.pl/articles/146738.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
semiconductors
gallium arsenide
swift heavy ions
inelastic energy loss
atomic force microscopy (AFM)
Opis:
We are presenting a study of damage distribution in GaAs irradiated with 84Kr ions of energy EKr = 394 MeV up to the fluence of 5 × 1012 ion/cm-2. The distribution of damage along the projected range of 84Kr ions in GaAs was investigated using selective chemical etching of a single crystal cleaved perpendicularly to the irradiated surface. The damage zone located under the Bragg peak of 84Kr ions was observed. Explanation of the observed effects based on possible processes of channeling of knocked target atoms (Ga and As) is proposed.
Źródło:
Nukleonika; 2008, 53, 2; 77-82
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of positron lifetime spectra in iron defected with highly energetic Bi and Kr ions
Autorzy:
Pietrzak, R.
Szatanik, R.
Glatki, K.
Powiązania:
https://bibliotekanauki.pl/articles/146340.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
ion implantation
defects
annihilation
Opis:
The positron lifetime spectra in iron defected with a beam of Bi+51 and Kr+27 ions of energies 670 MeV and 240 MeV, respectively, were investigated. These spectra were analysed by an appropriate separation in 1, 2 or 3 components. It has been found that the experimental data best fit to the assumed model if only two components are taken into account. For comparison, we investigated both irradiated and non-irradiated surfaces of the sample. We have taken into account the fact that the range of penetration of iron by Bi and Kr ions is small. The dependence of the positron lifetime spectra on the absorbed dose and kind of the bombarding ions is presented.
Źródło:
Nukleonika; 2010, 55, 1; 27-30
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bioaccumulation of uranium from waste water using different strains of Saccharomyces cerevisiae
Autorzy:
Tykva, R.
Novák, J.
Podracká, E.
Popa, K.
Powiązania:
https://bibliotekanauki.pl/articles/148088.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
bioaccumulation
uranium
Saccharomyces cerevisiae
competitive ions
Opis:
Five different strains of Saccharomyces cerevisiae were tested for their abilities to accumulate uranium from waste water containing competitive ions. Samples of water passing out from a previous uranium mill were used. The strains tested possess different abilities to accumulate uranium. The kinetics of bioaccumulation, the leaching degree, the influence of cell density and their origin were investigated. Under the applied experimental conditions, more than a half of the total activity (uranium and the decay products) could be accumulated after 60 min contact time of 1 mL S. cerevisiae suspension and 5 mL of water. The other cations present in solution effectively competed for the uranium accumulation. 226Ra and its decay products were completely retained using all tested strains.
Źródło:
Nukleonika; 2009, 54, 2; 143-148
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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