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Tytuł:
Modelling of components of resultant force during face milling
Autorzy:
Sekulić, M.
Kovač, P.
Powiązania:
https://bibliotekanauki.pl/articles/1429406.pdf
Data publikacji:
2008
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
face milling
cutting forces
Opis:
Cutting forces during face milling are investigated intensively analytically and experimentally. Some of previous approaches to cutting forces determination consider only main (tangential) cutting force component, and according to this define cutting power. The experimental investigations were performed during face milling with a goal to determine models of cutting force versus cutter revolution. Different models were determined according to the cutter approach to the workpiece during cutting angle of revolution.
Źródło:
Journal of Machine Engineering; 2008, 8, 2; 65-72
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A brief overview about the development of torsional vibration calculation and education of methods for their calculation
Autorzy:
Zoul, V.
Kováč, P.
Powiązania:
https://bibliotekanauki.pl/articles/198671.pdf
Data publikacji:
2018
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
propulsion systems
simulation methods
torsional vibration
GT-Power
układy napędowe
metody symulacji
drgania skrętne
Opis:
Torsional vibration calculation (TVC) is among the basic calculations that are required to support propulsion projects for various vehicles, ships and construction machines. A number of powerful software packages for these calculations already exists. However, the need to respect the physical properties of propulsion systems that are more complex than before has arisen. At the same time, knowledge about system properties and the capabilities of computing systems are also growing, resulting in an increase in new software systems, which could be used for these calculations. In this paper, these new trends are briefly described, with attention paid not only to practical use, but above all to how and to what extent these themes should be presented to students.
Źródło:
Zeszyty Naukowe. Transport / Politechnika Śląska; 2018, 99; 205-211
0209-3324
2450-1549
Pojawia się w:
Zeszyty Naukowe. Transport / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relation between Current Transfer Length and Stability of Fe/$MgB_2$ and Fe/Nb/$MgB_2$ Conductors
Autorzy:
Holúbek, T.
Kováč, P.
Hušek, I.
Powiązania:
https://bibliotekanauki.pl/articles/1813693.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.71.Mn
Opis:
This paper treats and confronts the stability of two different composite $MgB_2$ superconductors and searches for relation between the current transfer length and maximum heat flux that conductor can withstand in operational DC regime. It was found that the iron sheathed wire behave more stably than tape-like conductor with outer iron sheath and inner niobium barrier.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 367-370
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The internet/intranet application for cutting regime setting
Autorzy:
Kovač, P
Gostimirović, M.
Sekulić, M.
Pižurica, N.
Powiązania:
https://bibliotekanauki.pl/articles/100029.pdf
Data publikacji:
2010
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
optimal cutting regime
MySql data base
internet
Opis:
In the paper Inter for cutting conditions setting during turning is presented. For this task realization MySql data base and program language PHP was used. For this task realization MySql data base and program language PHP was used. This data base is completely free and functions on many operative systems (MS Windows, Linux, FreeBSD ...). Program language PHP has very simple syntax and les experienced users can learn how to use it very quickly As the result of this created was Internet/Intranet application that can be used on Internet also as on own net (Intranet). Application is located on Apache web server.
Źródło:
Journal of Machine Engineering; 2010, 10, 2; 18-24
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of model lightening system and design of PID controllers for the purpose of energy savings by using of MATLAB and their functionality in LabVIEW
Identyfikacja modelu systemu rozjaśniania i zaprojektowania regulatora PID w celu oszczędności energii przy wykorzystaniu programu MATLAB i funkcjonalności LabVIEW
Autorzy:
Nagy, L
Palková, Z
Valíček, J
Kiedrowicz, M
Rokosz, K
Kovač, P
Powiązania:
https://bibliotekanauki.pl/articles/1819293.pdf
Data publikacji:
2012
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
sterowanie wzrostu roślin
regulator PID
rośliny szklarniowe
sterowanie oświetleniem
Opis:
System sterowany jest częścią pętli i konieczne jest rozważenie go jako osobnej części z konkretnej nieruchomości. Podczas wyboru właściwego regulatora PID ważne jest, aby zrozumieć dynamiczne właściwości kontrolowanego systemu. Na opis tego obiektu zostały opracowane różne metody bilansów energii i następnych modeli matematycznych korygujących przejęcie funkcji transferowych. W praktyce lepiej jest użyć metod, których obserwujemy zachowanie dla konkretnych warunków systemowych (na przykład odpowiedzi na jednostkowy skok na wejściu lub częstotliwość sygnału). Według Behaving wiemy jak matematycznie opisać systemu i następnie wybrać właściwy rodzaj regulatora PID z jego parametrami. Ten artykuł skupia się na identyfikacji systemu oświetlenia dla uprawy roślin szklarniowych oraz prawidłowego zaprojektowania parametrów regulatora PID do sterowania oświetleniem, tak aby zorientowany był on na oszczędności energii.
Źródło:
Rocznik Ochrona Środowiska; 2012, Tom 14; 247-261
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Texture Evolution in Temper Rolled Fe-Si Steels with New System Nano-Inhibitors under the Dynamic Annealing Conditions
Autorzy:
Kováč, F.
Petryshynets, I.
Horňak, P.
Powiązania:
https://bibliotekanauki.pl/articles/356939.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
grain-oriented Fe-Si steels
abnormal grain growth
VC inhibitors
microstructure
texture
Opis:
This work investigates the microstructure and texture evolution in grain-oriented electrotechnical steel with a new inhibition system based on vanadium carbides nano-particles. The novel approach for the preparation of this steel with appropriate final magnetic properties combines not only nanoinhibitors based on the vanadium carbides precipitations but also includes straininduced grain growth mechanism in combination with dynamic continuous annealing during the secondary recrystallization. The experimental grain-oriented steel with proposed new chemical composition was prepared in laboratory conditions. The texture analysis has shown that suggested procedure led the formation of sufficiently strong {110}<001> Goss texture during the short time period of a final annealing process, which is comparable to that obtained in the conventionally treated grain-oriented steels.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1727-1732
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability analysis of forest machines due to FMEA method
Autorzy:
Ťavoda, P.
Kováč, J.
Łukaszczyk, Z. Ł.
Powiązania:
https://bibliotekanauki.pl/articles/409738.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
reliability
FMEA method
forest machines
maintenance
Opis:
The article deals with the research of operational reliability of forest felling machines with the method FMEA (Failure Mode and Effect Analysis) and its implementation for observed machines in the organization. Forwarders 810D by John Deere were chosen for this research. The research was realized in real operational conditions. Application of the FMEA method allows flexibility in case of unexpected situations and optimization of human potential abilities. FMEA tool is a tool preventing outages operational reliability and preventive tool for ensuring the maintenance of facilities. This paper explores and verifies the operational reliability theory in practical real-world conditions, resulting in a reduction in operating (variable) costs, minimization of failures and readiness and increased performance of observed machines.
Źródło:
Management Systems in Production Engineering; 2018, 4 (26); 200-206
2299-0461
Pojawia się w:
Management Systems in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of 1D Ordering on Magnetic Properties of Iron Nanoparticles coated by Silica Shell
Autorzy:
Zeleňáková, A.
Hrubovčák, P.
Zeleňák, V.
Kováč, J.
Powiązania:
https://bibliotekanauki.pl/articles/1030766.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
75.75.Fk
68.37.Og
Opis:
Peculiar magnetic properties of 1D arranged composite consisting of Fe nanoparticles coated by insulating SiO2 layer were studied. Silica layer promotes the self-organization of 4 nm iron nanoparticles to the chain-like structures. Magnetization study shows that prepared nanoparticles exhibit very strong inter-particle magnetic interactions, which lead to long-range ordering of nanoparticles magnetic moments. Magnetic properties show superferromagnetic behaviour. The low value of room temperature coercivity, the existence of electrical insulating silica layer and small size of iron nanoparticles favour studied material for potential usage in microelectronic devices designed for high voltage signals modulated by high frequencies.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 561-563
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Superparamagnetism in Cobalt Nanoparticles Coated by Protective Gold Layer
Autorzy:
Hrubovčák, P.
Zeleňáková, A.
Zeleňák, V.
Kováč, J.
Powiązania:
https://bibliotekanauki.pl/articles/1368320.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
75.75.Fk
68.37.Og
Opis:
In this work we present the study on structural and magnetic properties of fine cobalt nanoparticles coated by protective gold layer synthetized by microemulsion method. Structural measurements (powder XRD, HRTEM) confirmed spherical shape of the particles, their nanocrystalline character and presence of individual Co and Au phases. Investigation of magnetic properties of the particles revealed superparamagnetic behavior at higher temperatures and magnetic hysteresis at low temperatures. Average magnetic moment of individual particle $m_{p}~86.3μ_{B}$ was established. The critical temperature, below which the magnetic moments of the particles are blocked, was $T_{B}$=6 K. Investigation of magnetic relaxation processes via magnetic susceptibility, detected one maximum attributed to single relaxation process, present in the particles. Obtained data, interpreted in terms of Neél-Arrhenius and Vogel-Fulcher theoretical models, confirmed the presence of strong magnetic interparticle interactions.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 216-217
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Clean bulk YBaCuO superconductors doped by paramagnetic ions of Sm and Yb
Autorzy:
Jirsa, M.
Volochová, D.
Kováč, J.
Diko, P.
Powiązania:
https://bibliotekanauki.pl/articles/1054700.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Ha
74.25.Op
74.25.Sv
74.60.Ge
74.72.-h
Opis:
The recently developed clean cuprate technology was employed to study the effect of tiny amounts of paramagnetic Yb and Sm ions on electromagnetic properties of bulk YBaCuO. Small samples of about 1.5×1.5×0.5 mm³ were measured by vibrating sample magnetometer in the field range ±9 T and temperatures 30 K to 10 K in the non-superconducting tetragonal state and 300 K to 70 K in the orthorhombic, superconducting state. In the latter case, we observed the reversible paramagnetic moment above T_{C}, similar as in the tetragonal state. Below T_{C} an irreversible magnetic moment was observed from which critical current density, J_c, was evaluated using the extended Bean model. The effect of doping by Yb and Sm ions on J_c was studied and a correlation between J_c and the total paramagnetic moment was found. Both J_c(B) and the normalized pinning force density as a function of the reduced magnetic field were analyzed in terms of the classical model and discussed with respect to the material anisotropy, giving us at least a rough idea on the type of the effective pinning type and mechanism.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1027-1029
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Charcoal Supporting Silver as a Water Disinfectant
Autorzy:
Valušová, E.
Antalík, M.
Pristaš, P.
Javorský, P.
Kováč, J.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1201874.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Ni
75.60.Ej
75.47.Lx
81.05.U-
92.40.qc
Opis:
We investigated the magnetic behavior of charcoal composite with incorporated magnetite and silver ions. The magnetization curve measured at 282 K showed saturation magnetization of 8 emu/g. By benefiting from a mechanical process, the magnetic activated carbon, supporting silver ions (MCAG), acts as a magnetic filter uptaking the bacteria. This idea was confirmed by the DGGE analysis in which the bacterial DNA was detectable in the sediment after the treatment.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 226-227
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Zn on Structure and Magnetic Properties of Rapid Quenched (Fe-Zn)-Cu-Nb-Si-B Alloys
Autorzy:
Kolesar, V.
Michalik, S.
Kovac, J.
Girman, V.
Sovak, P.
Kollar, P.
Powiązania:
https://bibliotekanauki.pl/articles/1533958.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Hk
75.50.Bb
75.75.Cd
Opis:
The aim of this work was to study the influence of Zn on the formation of nanostructure in $Fe_{73.5 - x}Zn_xCu_1Nb_3Si_{13.5}B_9$ (x = 1, 3, 5) ribbons prepared by the melt-spinning technique. X-ray diffraction measurements proved amorphous state of the sample with x = 1. The sample with x = 3 contains a small fraction of Fe_3Si phase and the sample with x = 5 is in nanocrystalline state with the average grain size of about 25 nm. The reduced radial distribution function G(r) was calculated for local structure investigation. Increasing Zn content enhances crystallization during solidification which leads to increase of magnetocrystalline anisotropy and consequently to increase of coercivity.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 790-791
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of post partum uterine involution on folliculogenesis, oestrus and conception in cows
Wpływ poporodowej inwolucji macicy na folikulogenezę, ruję i zapłodnienie krów
Autorzy:
Zaleha, P.
Vargova, M.
Kadasi, M.
Smitka, P.
Smarzik, M.
Kovac, G.
Powiązania:
https://bibliotekanauki.pl/articles/843770.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Zootechniczne
Opis:
The ending of the puerperium has place when the first oestrus postpartum gestation is restored. To that end the anatomical and histological uterine involution must be completed and the hypothalamic-pituitary-gonadal axis must work properly to allow: oestrus, ovulation, conception, implantation, formation and persistence of corpus luteum of pregnancy. Therefore, early postpartum disorders such as NEB, abnormal gonadotropin secretion, uterine infection and other disorders could have subsequent deleterious effects on oocyte development and competence. However, low BCS coupled with severe NEB during this period suppresses pulsatile LH secretion, reduces ovarian responsiveness to LH stimulation and also reduces the functional competence of the follicle characterized by reduced oestradiol production and ultimately results in delayed ovulation. Normal oestrous cycles in cows coupled with overt signs of oestrus are essential so that insemination can occur at the appropriate time relative to ovulation. Also good nutrition management, environment conditions and welfare can support normal uterine postpartum involution and recurrence of cyclicity.
Okres poporodowy kończy się w momencie wystąpienia pierwszej rui po porodzie. Wcześniej musi się zakończyć anatomiczna i histologiczna inwolucja macicy, a także prawidłowo funkcjonować oś podwzgórzowo-przysadkowo-gonadowa, aby umożliwić ruję, owulację, zapłodnienie, implantację, powstanie i utrzymanie ciążowego ciałka żółtego. Wczesne zaburzenia poporodowe, takie jak ujemny bilans energetyczny (NEB – negative energy balance), anormalna sekrecja gonadotropin, zakażenie macicy i inne zaburzenia mogą mieć szkodliwy wpływ na rozwój i wydolność oocytów. Niska punktowa ocena kondycji krowy (BCS – body condition score) w połączeniu z drastycznym NEB w okresie poporodowym tłumi pulsacyjną sekrecję hormonu luteinizującego (LH – luteinizing hormone), obniża zdolność reakcji jajników na stymulację LH, a także zmniejsza wydolność funkcjonalną pęcherzyków, co charakteryzuje się obniżoną produkcją estradiolu, i wreszcie, powoduje opóźnioną owulację. Normalne cykle rujowe u krów oraz jawne oznaki rui to zasadnicze warunki, aby inseminacja mogła nastąpić we właściwym czasie w stosunku do owulacji. Także dobry system żywienia, prawidłowe warunki środowiskowe i dobrostan zwierząt mogą być czynnikami wspomagającymi normalną poporodową inwolucję macicy i powrót cykliczności rui.
Źródło:
Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego; 2013, 09, 1
1733-7305
Pojawia się w:
Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Polymer Immobilization on Magnetic Properties of Magnetosomes
Autorzy:
Timko, M.
Džarová, A.
Kovač, J.
Kopčanský, P.
Gojzewski, H.
Powiązania:
https://bibliotekanauki.pl/articles/1535115.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.30.Gw
75.50.Mm
75.50.Tt
75.60.Ej
Opis:
The anisotropy of several PVA/magnetosomes magnetically textured films has been investigated from the point of view of magnetic properties. The thin film synthesized under the influence of a magnetic field (99 mT) shows the typical behavior of an anisotropic material. On sample textured in magnetic field the magnetisation loop measurements were performed in dependence on the direction of the external magnetic field with respect to the texture axis. The results of hysteresis measurements show that the magnetic field applied during the synthesis promotes an orientation of the chains of magnetosomes and permanently textured film is obtained after solidification. The obtained values for magnetic remanence and coercivity were dependent on the external magnetic field orientation and the alignment effect of particle moments may be clearly seen which is in agreement with the theoretical model of magnetic particle chains.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 995-997
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystalline Structure, Stoichiometry and Magnetic Properties of the Morasko Meteorite
Autorzy:
Idzikowski, B.
Kováč, J.
Diko, P.
Stankowski, W.
Muszyński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1535541.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
91.65.Sn
75.50.Bb
67.80.dk
Opis:
The composition and structure of iron-nickel alloys smithereens extracted from the Morasko (Poland) Meteorite (fell ∿ 5 ka BP) were investigated by optical metallographic techniques, scanning electron microscopy and electron microprobe analysis, thermal analyses, magnetic measurements and X-ray diffraction. Microstructural analysis by scanning electron microscopy and optical microscopy has shown that the sample is composed from large grains of Fe-Ni alloy in which secondary phase crystals with well developed crystal habits and the size about 10 micrometers are distributed. Thermal analyses confirmed that the transformation from alpha to gamma Fe-Ni solid solution appearing as a function of temperature corresponds to about 5 wt% Ni in the Fe-Ni alloy. Possible scenario of the extraterrestrial sample solidification is related to the microstructural and magnetic behavior.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1071-1073
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
$[FeCl_{4}]¯$ Ionic Liquid Based Ferrofluids
Autorzy:
Parnica, J.
Kesa, P.
Kovac, J.
Timko, M.
Antalik, M.
Powiązania:
https://bibliotekanauki.pl/articles/1368745.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.kp
75.50.Bb
47.65.Cb
75.50.Mm
Opis:
Magnetic ionic liquids derived from hydrochloride methyl ester alanine amino acids (AA) and $FeCl_{3}$ were synthesized in ethanol and their magnetic properties were investigated. Iron (III) chloride forms ionic liquid in ethanol at saturated concentrations by the transfer of Cl¯ anion from one molecule of $FeCl_{3}$ to the other molecule with the creation of tetrachloro ferrate anion $[FeCl_{4}]$¯ as well as dimer $[Fe_{2}Cl_{7}]$¯. Raman scattering indicates that after addition of hydrochloride methyl ester alanine to ethanol solutions of $FeCl_{3}$ increase the intensities of signal at the frequencies at 318 $cm^{-1}$ and 380 $cm^{-1}$ as markers for the presence of $[FeCl_{4}]$¯ and $[Fe_{2}Cl_{7}]$¯ complexes. The magnetization at room temperature showed in both samples a linear dependence on the applied magnetic field. On the other hand, in the Raman scattering experiments the magnetization is smaller for $FeCl_{3}$ sample in the presence of methyl ester alanine.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 276-277
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Casting and Solidification of Slab Ingot from Tool Steel Using Numerical Modelling
Modelowanie numeryczne odlewania i krzepnięcia wlewków stalowych ze stali narzędziowej
Autorzy:
Tkadlečková, M.
Michalek, K.
Machovčák, P.
Kováč, M.
Socha, L.
Powiązania:
https://bibliotekanauki.pl/articles/356253.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steel
slab ingot
macrosegregation
cracks
modelling
stal
wlewki stalowe
segregacja
pęknięcia
modelowanie
Opis:
The main problem in the production of forgings from tool steels, especially thick plates, blocks, pulleys and rods which are used for special machine components for demanding applications, it is the inhomogeneous structure with segregations, cracks in segregations or complex type of non-metallic inclusions MnS and TiCN. These forgings are actually produced from conventional forging ingots. Due to the size of forgings, it would be interesting the production of these forgings from slab ingots. It is possible that the production of forgings from slab ingots (which are distinguished by a characteristic aspect ratio A/B), it would reduce the occurrence of segregations. The paper presents the verification of the production process of slab steel ingots in particular by means of numerical modelling using finite element method. The paper describes the pre-processing, processing and post-processing phases of numerical modelling. The attention was focused on the prediction of behavior of hot metal during the mold filling, on the verification of the final porosity, of the final segregation and on the prediction of risk of cracks depending on the actual geometry of the mold.
Głównym problemem w produkcji odkuwek ze stali narzędziowych, szczególnie grubych płyt, bloków, kół pasowych i prętów, używanych do specjalnych elementów maszyn dla żądanych zastosowań, jest niejednorodna struktura z segregacją, pęknięciami w segregacji lub złożonego typu niemetaliczne wtrącenia MnS i TiCN. Te odkuwki są rzeczywiście produkowane z konwencjonalnych wlewków przeznaczonych do kucia. Ze względu na wielkość odkuwek, można by produkować te odkuwki z wlewków płaskich. Możliwe, że produkcja odkuwki z wlewków płaskich (które wyróżniają się charakterystycznym stosunkiem A/B), pozwoli zmniejszyć występowanie segregacji. W pracy przedstawiono weryfikację procesu produkcji wlewków płaskich za pomocą modelowania numerycznego z wykorzystaniem metody elementów skończonych. Artykuł opisuje fazy modelowania numerycznego: wstępną fazę przetwarzania, obróbkę i przetwarzanie końcowe. Zwrócono uwagę na zachowanie się ciekłego metalu podczas napełniania wlewnic, na weryfikację końcowej porowatości, końcowej segregacji i przewidywania ryzyka pęknięcia w zależności od rzeczywistej geometrii wlewnic.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 4; 2879-2886
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Co Doping on Induced Anisotropy and Domain Structure in Magnetic Field Annealed $(Fe_{1-x}Co_x)_{79}Mo_8Cu_1B_{12}$
Autorzy:
Kunca, B.
Marcin, J.
Švec, P.
Kováč, J.
Švec Sr., P.
Škorvánek, I.
Powiązania:
https://bibliotekanauki.pl/articles/1398273.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.50.Tt
75.60.Ch
75.60.Nt
Opis:
The effect of heat treatment in applied magnetic field on the induced anisotropy and domain structure of $(Fe_{1-x}Co_x)_{79} Mo_8 Cu_1 B_{12}$ (x=0, 0.2, 0.5) nanocrystalline alloy system was investigated. A heat treatment of Co-doped samples under the application of longitudinal magnetic field resulted in squared hysteresis loops characterized by very low coercive field values. Sheared loops with tunable slope and good field linearity were obtained after annealing in transverse magnetic field. Corresponding domain structure showed uniform character, oriented in the direction parallel or perpendicular to the ribbon axis after longitudinal or transverse magnetic field annealing, respectively. No effect of magnetic field annealing was found in Co-free sample. Correlations between Co-doping, the Curie temperature, and soft magnetic properties after magnetic field annealing are discussed.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 759-761
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Composites Consisting of High-T$\text{}_{c}$ Superconductor and Fine Magnetic Particles
Autorzy:
Timko, M.
Kopčanský, P.
Kováč, J.
Koneracká, M.
Plecháček, V.
Powiązania:
https://bibliotekanauki.pl/articles/2013009.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.Hs
75.50.Tt
Opis:
The composite systems as a mixture of fine magnetic particles of Fe$\text{}_{3}$O$\text{}_{4}$ and superconducting powder such as Bi$\text{}_{1.8}$Pb$\text{}_{0.2}$Sr$\text{}_{2}$Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{10+x}$ were prepared. The influence of internal magnetic field (generated by magnetic particles) on the superconducting properties of prepared composites were studied as a function of concentration of magnetic particles and their magnetic state. The observed data both of the shielding and the Meissner effect were compared with corresponding linear combination of pure signals of magnetite and superconductor, respectively. The large differences were observed for demagnetized samples. It means that result must be discussed in the frame of the distribution of internal magnetic field created by the magnetic particles.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 389-392
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of spark plasma sintering on microstructure and properties of bulk LaCaSrMnO magnetocaloric materials
Autorzy:
Zmorayová, K.
Antal, V.
Kováč, J.
Diko, P.
Noudem, J.
Powiązania:
https://bibliotekanauki.pl/articles/1053176.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
61.72.-y
75.30.Kz
77.80.B-
81.70.Pg
81.20.Ev
81.30.Fb
Opis:
Polycrystalline La_{0.67}Ca_{0.33-x}Sr_xMnO₃ (x=0.33, 0.03, 0) (LCSM) perovskite samples treated by spark plasma sintering technique were investigated. This study proved influence of the sintering temperature on microstructure of these perovskite ceramics. The thermogravimetric measurements revealed the possibility of increase of oxygen content in studied LCSM samples by additional annealing under oxygen atmosphere and low temperature. Finally, the effect of this annealing on magnetic properties was demonstrated.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 804-806
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Mechanochemically Synthesized Mixed Oxides
Autorzy:
Kostova, N.
Zorkovská, A.
Kováč, J.
Velinov, N.
Baláž, P.
Powiązania:
https://bibliotekanauki.pl/articles/1372521.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.84.Bw
75.60.-d
76.80.+y
61.05.cp
81.07.Wx
Opis:
The mixed oxides $Fe_{2}O_{3}-ZnO$ have been obtained in nanocrystalline state by reactive milling in a high-energy planetary mill, from a stoichiometric mixture of hematite and ZnO. The magnetic properties of samples were evaluated by magnetization measurements and Mössbauer spectrometry. A post milling annealing promotes the solid state reaction and improves the zinc ferrite formation, paramagnetic $ZnFe_{2}O_{4}$ phase is formed. Further mechanical activation leads to structural transformation into Wüstite-type (FeZn)O mixed oxide, with ferromagnetic hysteresis and increased magnetization.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 411-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of Magnetoferritin
Autorzy:
Mitróová, Z.
Melníková, L.
Kováč, J.
Timko, M.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1429123.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.50.Ee
75.60.Ej
75.50.Tt
Opis:
The paper presents detailed experimental study of synthesis and characterization a bioinorganic magnetic molecule - magnetoferritin. Magnetoferritin with loading of iron ions per protein molecule in the range from 300 to 3000 was prepared. Size distribution analysis (transmission electron microscopy, dynamic light scattering) shows spherical nanoparticles with particle size distribution from 2 to 12 nm, and hydrodynamic diameter from 12 to 25 nm. The thermomagnetic curves measured after cooling the sample in zero field (zero-field cooling) and under the presence of the measurement field (field cooling) show superparamagnetic behavior with the blocking temperature $T_{b}$ from 22 to 60 K and the magnetization loops measured below $T_{b}$ (at 2 K) show the hysteresis with coercive field from 20 to 30 kA/m depending on the concentration of the magnetic nanoparticles.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1318-1320
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of market valuation models in portfolio management
Zastosowanie modeli wyceny rynkowej w zarządzaniu portfelem
Autorzy:
Pastor, D.
Kisela, P.
Kovac, V.
Sabol, T.
Vajda, V.
Powiązania:
https://bibliotekanauki.pl/articles/406119.pdf
Data publikacji:
2015
Wydawca:
Politechnika Częstochowska
Tematy:
valuation indicators
market valuation
portfolio management
investment strategy
efficiency market hypothesis
undervaluation
overvaluation
wskaźniki wyceny
wycena rynkowa
zarządzanie portfelem
strategia inwestycyjna
hipoteza wydajności rynku
zaniżona wycena
zawyżona wycena
Opis:
The paper deals with application of market valuation models in portfolio management. Its aim is to find out if it is possible to gain excess returns with simple investment strategies based on indicators constructed from some well-known ratios that are used to detect undervaluation or overvaluation of stock market. The theoretical background is followed by an overview of other studies in this field. In the next chapter Tregler’s market valuation indicators and the created investment strategies are discussed. Portfolio management approaches for different indicators were tested on historical S&P 500 monthly close prices. Any of chosen approaches was not able to achieve a higher return than basic buy and hold strategy. One strategy achieved return comparable to benchmark, but with lower risk, so it may be suitable for some portfolio managers.
Niniejszy artykuł dotyczy stosowania technik wyceny rynkowej w zarządzaniu portfelem. Jego celem jest dowiedzieć się, czy możliwe jest uzyskanie nadwyżki zysków dzięki prostym strategiom inwestycyjnym opartym na wskaźnikach skonstruowanych z kilku znanych współczynników, które używane są do wykrywania zaniżonej lub zawyżonej wyceny rynku akcji. Po tle teoretycznym zaprezentowano przegląd innych badań w tej dziedzinie. W kolejnym rozdziale omawiane są wskaźniki wyceny rynkowej Treglera oraz stworzone strategie inwestycyjne. Podejścia zarządzania portfelem dla różnych wskaźników testowane były na historycznych miesięcznych kursach zamknięcia S&P 500. Żadne z wybranych podejść nie było w stanie osiągnąć wyższego zwrotu niż podstawowa strategia „kup i trzymaj”. Jedna ze strategii osiągnęła zwrot porównywalny do poziomu odniesienia, ale z mniejszym ryzykiem, a więc może być ona odpowiednia dla niektórych zarządzających portfelami.
Źródło:
Polish Journal of Management Studies; 2015, 12, 1; 154-165
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of Sm addition on the microstructure and superconducting properties of YBCO bulk superconductors
Autorzy:
Volochová, D.
Diko, P.
Piovarči, S.
Antal, V.
Kováč, J.
Jirsa, M.
Powiązania:
https://bibliotekanauki.pl/articles/1054772.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.-h
74.62.Dh
81.10.Fq
61.72.-y
74.25.Ha
74.25.Sv
Opis:
The effect of Sm addition on the microstructure and superconducting properties of Y-Ba-Cu-O (YBCO) bulk superconductors has been studied. Nominal composition: 1 mol YBa₂Cu₃O_{7-δ} + 0.25 mol Y₂O₃ + 1 wt% CeO₂ was enriched with different amounts of SmBa₂Cu₃O_y powder with the aim to increase critical current density, J_c, especially in higher magnetic fields by introducing additional pinning centers. Single grain YBCO bulk superconductors with SmBa₂Cu₃O_y (Y123-Sm) addition were prepared by the optimized top seeded melt growth process. Microstructure analysis, performed by polarized light microscope, revealed that SmBa₂Cu₃O_y addition leads to a higher amount of slightly coarser Y₂BaCuO₅ particles, which is related to lower critical current densities (J_c ≈ 6×10⁴ A/cm²) of the YBCO samples with SmBa₂Cu₃O_y addition in low magnetic fields. On the other hand, an enhancement of critical current density, J_c, in higher magnetic fields was observed for Y123-Sm samples. Moreover, a maximum trapped magnetic field, B_{tmax}, of 564 mT at 77 K in Y123-Sm, x=0.0025 sample (Ø 17.2 mm) was 43% higher than that for YBCO sample without any addition.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1009-1011
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Complex Characterization of Magnetic Nanoparticles in Magnetic Fluid
Autorzy:
Kubovčíková, M.
Antal, I.
Kováč, J.
Závišová, V.
Koneracká, M.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1201928.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.75.Fk
78.67.Bf
36.40.Cg
47.65.Cb
75.50.Mm
75.30.Cr
Opis:
This paper deals with the preparation and complex characterization of magnetite nanoparticles (MNPs), stabilized with sodium oleate (SO), by the routine methods such as infrared spectroscopy (FTIR), magnetic measurements, scanning electron microscopy (SEM) and dynamic light scattering (DLS). The FTIR spectra showed that SO molecules were linked to MNPs through chemical bonding. Magnetic measurements proved that the MNPs are superparamagnetic in nature. Four different methods were used to determine the size and size distribution of the MNPs: SEM, DLS, differential centrifugal sedimentation (DCS) and magnetic measurements. SEM analysis showed a relatively narrow size distribution of roughly spherical MNPs with a mean diameter of 61 nm. DLS analysis confirmed monodispersed MNPs production with hydrodynamic diameter of 75 nm. The size distribution determined by DCS was found to be 69 nm. Finally, the calculated magnetic core diameter obtained from magnetization curve was 10 nm. The obtained results demonstrate that SO coated MNPs fulfil the requirements for a useful drug delivery system.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 268-269
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical Current Density and Microstructure of $NdBa_2Cu_3O_7$ Single Crystal
Autorzy:
Diko, P.
Zmorayová, K.
Šefčiková, M.
Antal, V.
Kováč, J.
Yao, X.
Powiązania:
https://bibliotekanauki.pl/articles/1535339.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Ha
74.25.Sv
74.62.Bf
Opis:
The top-seeded solution growth method was used to grow NdBCOss single crystals in air. The microstructure of the samples has shown that the oxygenation crack structure developed in the single crystals. The intrinsic critical current density was estimated to be at least twice higher than the value of volume critical current density determined from the magnetization measurements.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1028-1030
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effects of Laser Surface Hardening on Microstructural Characteristics and Wear Resistance of AISI H11 Hot Work Tool Steel
Autorzy:
Šebek, M.
Falat, L.
Kováč, F.
Petryshynets, I.
Horňak, P.
Girman, V.
Powiązania:
https://bibliotekanauki.pl/articles/352543.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hot work tool steel
laser hardening
microstructure
hardness
wear resistance
Opis:
The present study deals with the effects of laser surface treatment on microstructure evolution and wear resistance of AISI H11 hot work tool steel in quenched and tempered condition. The most upper laser-affected zone is characterized by re-melted microstructure consisting of dendrite cells with fresh non-tempered martensite, retained austenite and inter-dendritic carbidic network. The subsolidus microstructure just beneath the re-melted zone represents the most laser surface hardened zone consisting of fresh non-tempered martensite with fine and coarse carbides as a result of overheating the original QT substrate microstructure. The highest microhardness values in the range from 775 to 857 HV were measured for the LSH microstructure and the most softened microstructure exhibited the minimum hardness of 530 HV. The laser treated samples showed the improvement of their surface wear resistance by 35%.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1721-1726
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemically Synthesized CuFeSe₂ Nanoparticles and Their Properties
Autorzy:
Dutková, E.
Škorvánek, I.
Sayagués, M.
Zorkovská, A.
Kováč, J.
Baláž, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032137.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Hd
81.07.Wx
81.20.Wk
Opis:
The mechanochemical synthesis of nanocrystalline CuFeSe₂ particles prepared by high-energy milling in a planetary mill in an argon atmosphere from copper, iron, and selenium for 60 min is reported for the first time. The CuFeSe₂ nanoparticles crystallize in tetragonal structure with mean crystallite size of about 32±1 nm. High resolution transmission electron microscopy measurements confirmed the presence of agglomerates which are formed by small nanocrystalline domains (5-40 nm). The magnetic data revealed that paramagnetic CuFeSe₂ nanoparticles coexist with a small amount of ferromagnetic impurities at room temperature. The magnetic transition towards a weak ferromagnetic or ferrimagnetic behavior occurs in CuFeSe₂ at approximately 79 K. The band gap of the CuFeSe₂ particles is 0.95 eV which is wider than the band gap in bulk materials (0.16 eV), which could be in many aspects of application more beneficial.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1156-1158
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Carbon Nanotubes
Autorzy:
Jeníková, M.
Zakuťanská, K.
Kováč, J.
Girman, V.
Kopčanský, P.
Tomašovičová, N.
Powiązania:
https://bibliotekanauki.pl/articles/1032760.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.48.De
74.25.nd
68.37.Lp
75.75.-c
Opis:
The aim of the presented work was to characterize single-walled carbon nanotubes as well as multi-walled carbon nanotubes by transmission electron microscopy, the Raman spectroscopy and magnetization measurements to obtain information about their size, structure, and magnetic properties. We show that having different carbon nanotubes one can easily distinguish the single-wall or multi-wall carbon nanotubes and determine their quality. The obtained results show that carbon nanotubes can be diamagnetic or ferromagnetic depending on their structural parameters.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 952-954
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pliocene to Quaternary stress field change in the western part of the Cen tral West ern Carpathians (Slovakia)
Autorzy:
Vojtko, R.
Hók, J.
Kováč, M.
Sliva, L’.
Joniak, P.
Šujan, M.
Powiązania:
https://bibliotekanauki.pl/articles/2060207.pdf
Data publikacji:
2008
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Western Carpathians
fault-slip data
Quaternary stress field
neotectonics
palaeostress analysis
Opis:
Knowledge of the current tectonic regime plays an essential role in natural hazard assessment, especially in the risk assessment of fault activity. Structural analysis of brittle deformations (using in version techniques) was used to determine the stress field state occurring within Pliocene and Quaternary deposits in the western part of the Central Western Carpathians. The deformation pattern of the reduced stress tensor showed that all structural measurements could be separated into two groups. An older, Late Pliocene fault population was activated un der NNW-SSE oriented extension. A younger, Quaternary fault population reflected origin in a NE–SW extensional tectonic regime and it distinctly showed a change the orientation of the S3 of about 70. The change in tectonic activity, as well as in the stress field orientation, is dated to the Pliocene-Pleis to cene boundary. The Quaternary stress field developed dur ing the post-collisional stage of the orogen. Our study shows that the West ern Carpathian internal units document NE-SW to NNE-SSW extension in the broader region around of the north ern Danube Basin.
Źródło:
Geological Quarterly; 2008, 52, 1; 19-19
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Bacterial Nanoparticles
Autorzy:
Timko, M.
Džarová, A.
Kováč, J.
Kopčanský, P.
Gojzewski, H.
Szlaferek, A.
Powiązania:
https://bibliotekanauki.pl/articles/1810601.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.65.Cb
51.60.+a
75.30.Gw
75.50.Tt
75.60.Nt
75.60.Ej
75.75.+a
Opis:
The objective of this study is to prepare and study magnetic properties of biological magnetic nanoparticles (magnetosomes) as a product of biomineralization process of magnetotactic bacteria Magnetospirillum sp. AMB-1. From temperature dependence of remanent magnetization and coercive field the Verwey transition is clearly seen at 105 K as a consequence of the large anisotropy along the chains of magnetosomes.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 381-383
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Andreev Reflection Spectroscopy Study of Spin Polarization in Co₂Cr(Fe)Al Heusler Alloys
Autorzy:
Hašková, V.
Szabó, P.
Kováč, J.
Ryba, T.
Vargová, Z.
Varga, R.
Powiązania:
https://bibliotekanauki.pl/articles/1385695.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Ba
74.45.+c
77.80.bg
Opis:
The present paper is dealing with the experimental study of the influence of Fe substitution on the Curie temperature and spin polarization in Co₂CrAl Heusler alloys. A recently successfully introduced new rapid quenching method has been used for the preparation of Co₂CrAl and $Co₂Cr_{0.6}Fe_{0.4}Al$ ribbon samples. The Curie temperatures have been determined from magnetization measurements being 378 K for Co₂CrAl and much above 400 K for $Co₂Cr_{0.6}Fe_{0.4}Al$. The spin polarization parameter P₀ of the studied samples has been estimated from point-contact Andreev reflexion spectroscopy measurements. In pure Co₂CrAlP₀ = 0.5 - 0.9, and in the case of $Co₂Cr_{0.6}Fe_{0.4}AlP₀$ = 0.4 - 0.9. Hence, it is shown that Fe substitution of Cr in $Co₂Cr_{1-x}FeₓAl$ Heusler alloys at a concentration of x=0.4 significantly increase the Curie temperature without marked influence on the spin polarization.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 377-378
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Temperature on Magnetization Processes in Amorphous Rapidly Solidified FeSiB/CoSiB Bilayer Ribbons
Autorzy:
Capik, M.
Švec, P.
Marcin, J.
Kováč, J.
Sopko, M.
Janičkovič, D.
Škorvánek, I.
Powiązania:
https://bibliotekanauki.pl/articles/1200803.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Kj
75.60.Ej
75.80.+q
Opis:
Amorphous bilayers consisting of Fe-Si-B and Co-Si-B layers have been prepared by planar flow casting from a single crucible using a double-nozzle technique. Temperature dependencies of magnetization and hysteresis loops have been investigated in a wide temperature range. At room temperature, the effects of interlayer stresses, induced in material due to different thermal expansion coefficients of two mechanically interconnected soft magnetic layers, resulted in rounded hysteresis loops with flattened central part, indicating a dominant role of magnetization rotational processes. With an increase of measurement temperature, the interlayer stresses are relieved and the hysteresis loops became more squared.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 120-121
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Birefringence Study of the Magnetic Core Structure of Ferritin
Autorzy:
Koralewski, M.
Pochylski, M.
Mitróová, Z.
Melníková, L.
Kováč, J.
Timko, M.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1428622.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ls
87.15.-v
87.85.jf
Opis:
Magnetically induced optical birefringence (Δ n) was measured for magnetoferritin and horse spleen ferritin aqueous suspensions. The Δ n for magnetoferritin was described in the frame of the Langevin formalism taking into account distribution of core diameter. The established average magnetic dipole moment and core diameter is equal to about 460 $μ_{B}$ and 3 nm, respectively. It was shown that magnetic birefringence and the Cotton-Mouton constant can be powerful parameters in identification of the magnetic core structure of ferritin, especially useful in biomedicine.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1237-1239
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Magnetic Properties of La-Ca-Sr-Mn-O Perovskite Ceramics
Autorzy:
Zmorayova, K.
Antal, V.
Radusovska, M.
Piovarci, S.
Kováč, J.
Kavecansky, V.
Diko, P.
Powiązania:
https://bibliotekanauki.pl/articles/1367705.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.47.Lx
77.80.Bh
81.20.Ev
81.30.Fb
Opis:
$La_{0.67}Ca_{0.33-x}Sr_{x}MnO_{3}$ (x=0.33; 0.03; 0) (LCSM) perovskite magnetocaloric ceramics were prepared by solid state synthesis in air and sintering at 1520°. The phase composition was checked by x-ray powder diffraction. Microstructure analyses were done by scanning electron microscopy. The influence of high pressure oxygenation on magnetisation behaviour is shown.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 168-169
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Viscosity Dependence of a Magnetic Fluid Nanoparticles Concentration
Autorzy:
Tóthová, J.
Kováč, J.
Kopčanský, P.
Rajňák, M.
Paulovičová, K.
Timko, M.
Józefczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1201929.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.55.Jg
75.50.Mm
83.85.Jn
Opis:
In this work we have studied the effect of temperature on the viscosity of magnetic fluids (MFs) based on the transformer oil ITO 100. The volume concentration of suspended magnetic particles (MPs) changed from 0.25 to 1%. Rheological characterization of MFs was performed using a vibroviscometer at working frequency of 30 Hz. The temperature dependence of the viscosity was measured in the temperature range from 20 up to 50 °C. The magnetization of different concentrations of MPs in MFs was determined by using the vibrating sample magnetometer.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 278-279
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties and Sorption Activity of Mechanically Activated Magnetite $Fe_3O_4$
Autorzy:
Baláž, P.
Timko, M.
Kováč, J.
Bujňáková, Z.
Ďurišin, J.
Myndyk, M.
Šepelák, V.
Powiązania:
https://bibliotekanauki.pl/articles/1535173.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.Ej
61.05.cp
76.80.+y
Opis:
It is known that the action of mechanical forces on solids (mechanical activation and/or mechanochemistry) leads to changes of their properties and reactivity. We have studied the physico-chemical and sorption properties of magnetite $Fe_3O_4$ (Kiruna, Sweden) mechanically activated in a planetary mill. Several methods such as X-ray diffractometry, Mössbauer spectroscopy, magnetometry, specific surface area measurement as well as arsenic sorption tests have been applied. By X-ray diffractometry strong amorphisation of magnetite has been evidenced. In parallel, specific surface area increased from 0.1 $m^2//g$ for the reference (non-milled) sample to the values 0.5-6.1 $m^2//g$ for milled samples. The Mössbauer spectrum of the reference sample is well fitted with two subspectra corresponding to tetrahedrally (A) and octahedrally (B) coordinated iron cations in the spinel structure of $Fe_3O_4$. In mechanically activated samples (B)-site subspectrum becomes asymmetric, while (A)-site spectrum remains more or less unchanged. The more covalent character of the Fe(A)-O bond compared to the Fe(B)-O bond can explain qualitatively why the spin-density transfer from (A) to (B) in the spinel structure is more effective than vice versa. The value of the saturation magnetization at room temperature was 67.4 ≈ 43.6 emu/g which is significantly lower than that of the bulk particles 92 emu/g. This reduction may be attributed to the surface disorder or spin canting at the particle surface. During the milling process the coercivity value increases from 150 Oe up to 460 Oe with milling time. This increase can be related to the fact that magnetic anisotropy may increase when particle size decreases. The sorption activity of $Fe_3O_4$ was enhanced as a consequence of its disordering: 88% of $As^{3+}$ was captured for the mechanically activated sample in comparison with 0% for the non-milled one.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1005-1007
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Properties of Magnetite Nanoparticles Covered by 11-Mercaptoundecanoic Acid
Autorzy:
Timko, M.
Kopčanský, P.
Antalik, M.
Simsikova, M.
Valusova, E.
Molcan, M.
Kováč, J.
Powiązania:
https://bibliotekanauki.pl/articles/1429127.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.65.Cb
85.70.-w
75.30.Cr
75.47.Lx
Opis:
We have investigated the magnetic behavior of magnetite nanoparticles covered by the 11-mercaptoundecanoic acid around magnetite core prepared by a standard co-precipitation method. The particles show superparamagnetic behavior at room temperature, with transition to a blocked state at blocking temperature 91 K estimated from zero field cooled and field cooled at 500 Oe experiment. The hysteresis loop measured at 293 K showed magnetization 32.8 emu/g at 50 kOe without any coercivity. The mean particle size (7.1 nm) was determined by fitting a magnetization curve obtained at 295 K assuming a log-normal size distribution.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1321-1323
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Soft Magnetic Properties and Temperature Stability of Co-Fe-Zr-B Metallic Glasses
Autorzy:
Bednarčík, J.
Kováč, J.
Roth, S.
Fűzer, J.
Kollár, P.
Varga, L.
Franz, H.
Powiązania:
https://bibliotekanauki.pl/articles/1813531.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Kj
Opis:
In the present work multicomponent Co-based alloys with nominal composition $Co_{72-x}Fe_xZr_8B_{20}$ (x=10, 15, and 20 at. %) were synthesized by single-roller melt-spinning. The measurement of coercivity, $H_c$, reveals the soft magnetic behavior of investigated alloys. The value of $H_c$ increases from 23 A/m for alloy with x=10 at. % up to 32 A/m for alloy with x=20 at. %. Further it was found that crystallization temperature of as-quenched alloys slightly varies with iron content and lays between 605 and 625°C. From the temperature dependence of magnetization it follows that partial substitution of cobalt by iron has positive influence on the Curie temperature of amorphous phase, $_cT^{am}$, which increases from 300°C up to 462°C for alloy with x=10 at. % and x=2 0 at. %, respectively.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 83-86
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and Properties of Soft-Magnetic Amorphous Bilayer Ribbons
Autorzy:
Švec, P.
Mat'ko, I.
Marcin, J.
Kováč, J.
Vlasák, G.
Janičkovič, D.
Škorvánek, I.
Powiązania:
https://bibliotekanauki.pl/articles/1534100.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.Hk
68.37.Lp
Opis:
Rapidly quenched bilayers consisting of Fe-Si-B and Co-Si-B layers have been prepared by planar flow casting from a single crucible with two nozzles. Temperature dependences of electrical resistivity, dilatation and magnetization have been investigated in the amorphous state and during crystallization of both layers. Preliminary studies of the structure of the layers and of the interlayer have been performed by X-ray diffraction, cross-sectional electron microscopy and microanalysis. From the results it seems evident that the process of connection of the two layers during preparation takes place by solidification with only a small extent of mutual interdiffusion of component atoms localized to a narrow well-defined interface, leading to mechanically solid connection between the two layers. The effect of combined presence of two different soft magnetic alloys on the overall magnetic properties is discussed with respect to potential applications of such materials.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 832-834
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Correlation between Magnetic and Structural Properties in Ni-Ti-Zr Metallic Glass
Autorzy:
Lisnichuk, M.
Katuna, Yu.
Saksl, K.
Girman, V.
Gamcová, J.
Balga, D.
Ďurišin, M.
Kováč, J.
Kollár, P.
Sovák, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032297.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.85.Jy
75.50.Kj
61.43.Dq
Opis:
The Ni-Ti-Zr metallic glasses are due to their known shape memory properties promising alloys e.g. for micromechanical applications. In this paper structure and structure stability of one particular alloy Ni₆₀Ti₂₅Zr₁₅ at.% were examined by means of X-ray diffraction and transmission electron microscopy while magnetic properties were ascertained by vibrating-sample magnetometer with maximal applied field of 100 kA/m in the temperature range of 300-1073 K.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 741-743
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemical Reduction of Chalcopyrite CuFeS₂: Changes in Composition and Magnetic Properties
Autorzy:
Baláž, P.
Zorkovská, A.
Baláž, M.
Kováč, J.
Tešinský, M.
Osserov, T.
Guseynova, G.
Ketegenov, T.
Powiązania:
https://bibliotekanauki.pl/articles/1032642.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
81.05.Hd
Opis:
High-energy milling of sulphides with a reactive metal in so-called mechanochemical reduction mode can lead to products in nanorange and to composition which simplifies the following metallurgical processing. Chalcopyrite CuFeS₂, a ternary semiconductor with antiferromagnetic properties represents promising candidate as an advanced material for use in inexpensive nanoelectronics (solar cells, magnetic area), as well as copper ore source in metallurgical operations. In this work, the process of mechanochemical reduction of chalcopyrite with elemental iron is studied. The composition and properties of nanopowder prepared by high-energy milling were analyzed by X-ray diffraction and magnetic measurements. Most of the reaction takes place during 30 min with chalcocite Cu₂S and troilite FeS as the only reaction products. The magnetic investigations reveal significant increase of saturation magnetization as a result of milling. Unlike the conventional high-temperature reduction of chalcopyrite, the mechanochemical reduction is fast and ambient temperature and atmospheric pressure are sufficient for its propagation.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1165-1167
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time Dependent Changes in Ag Doped YBCO Superconductors
Autorzy:
Volochová, D.
Antal, V.
Diko, P.
Šefčiková, M.
Zmorayová, K.
Kováč, J.
Weber, H.
Chaud, X.
Powiązania:
https://bibliotekanauki.pl/articles/1535451.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Ha
74.25.Sv
74.62.Bf
74.62.Dh
74.62.Fj
Opis:
Magnetization measurements at 77 K were conducted on the single-crystalline samples of YBCO superconductor doped with Ag prepared by the top-seeded melt-growth process. The single-grain samples had a nominal composition $Y_{1.5}Ba_2(Cu,Ag)_3O_{y}$. Magnetization measurements on the samples, oxygenated by two different processes: by standard oxygenation and by high pressure oxygenation, repeated after 24 months, revealed time dependent changes in magnetization behaviour and critical transition temperatures, T_{c}, which could be associated with redistribution of oxygen vacancies and their interaction with Ag dopant atoms.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1047-1048
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Sm and Yb Pollution on Superconducting Properties of YBCO Bulk Superconductors
Autorzy:
Volochová, D.
Jurek, K.
Radušovská, M.
Piovarči, S.
Antal, V.
Kováč, J.
Jirsa, M.
Diko, P.
Powiązania:
https://bibliotekanauki.pl/articles/1371573.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.60.Bf
74.72.-h
81.40.Rs
74.25.Ha
74.81.Bd
74.25.Op
Opis:
$YBa_{2}Cu_{3}O_{7-δ }$ (YBCO, Y-123) bulk superconductors with a nominal composition $Y_{1.5}Ba_{2}Cu_{3}O_{x}$ and 1 wt% $CeO_{2}$ addition were prepared by the Top Seeded Melt Growth (TSMG) process. Small single-crystalline pieces, cut from the $SmBa_{2}Cu_{3}O_{y}$ (Sm-123) bulk, were used for seeding of epitaxial growth. Wavelength-dispersive spectrometry (WDS) confirmed the presence of 0.1 wt% Sm from the seed and 0.25 wt% Yb from the substrate, practically in the whole sample volume. The influence of this Sm and Yb contamination on superconducting properties of grown bulk materials is reported.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 358-359
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanochemically Synthesized Nanocrystalline $Sb_2S_3$ Particles
Autorzy:
Dutková, E.
Sayagués, M.
Real, C.
Zorkovská, A.
Baláž, P.
Šatka, A.
Kováč, J.
Ficeriová, J.
Powiązania:
https://bibliotekanauki.pl/articles/1375343.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Hd
81.07.Bc
81.20.Wk
Opis:
Nanocrystalline $Sb_2S_3$ particles have been synthesized from Sb and S powders by high-energy milling in a planetary mill using argon protective atmosphere. X-ray diffraction, particle size analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electron diffraction, high resolution transmission electron microscopy, UV-VIS, and differential scanning calorimetry methods for characterization of the prepared particles were applied. The powder X-ray diffraction pattern shows that $Sb_2S_3$ nanocrystals belong to the orthorhombic phase with calculated crystallite size of about 36 nm. The nanocrystalline $Sb_2S_3$ particles are constituted by randomly distributed crystalline nanodomains (20 nm) and then these particles are forming aggregates. The monomodal distribution of $Sb_2S_3$ particles with the average hydrodynamic parameter 210 nm was obtained. The quantification of energy dispersive X-ray spectroscopy analysis peaks give an atomic ratio of 2:3 for Sb:S. The optical band gap determined from the absorption spectrum is 4.9 eV, indicating a considerable blue shift relative to the bulk $Sb_2S_3$. Differential scanning calorimetry curves exhibit a broad exothermic peak between 200 and 300°C, suggesting recovery processes. This interpretation is supported by X-ray diffraction measurements that indicate a 23-fold increase of the crystallite size to about 827 nm as a consequence of application of high temperature process. The controlled mechanochemical synthesis of $Sb_2S_3$ nanoparticles at ambient temperature and atmospheric pressure remains a great challenge.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 943-946
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
AC Magnetic Susceptibility of Ferrofluids Exposed to an External Electric Field
Autorzy:
Rajňák, M.
Dolník, B.
Kováč, J.
Paulovičová, K.
Mitróová, Z.
Kurimský, J.
Cimbala, R.
Kopčanský, P.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032260.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.65.Cb
75.75.Fk
75.78.-n
83.60.Np
Opis:
It is known that ferrofluid superparamagnetic nanoparticles response to external magnetic fields, often resulting in the formation of elongated clusters along the field. This has a notable impact on dielectric properties of ferrofluids. Here we report on indications of a contrary effect when the magnetic susceptibility of ferrofluids based on transformer oil is influenced by an external electric field. This effect is associated with structural changes in the ferrofluids induced by the external electric fields. Particularly, we focus on a steady state electric field effect, which gives rise to forces acting on the magnetite nanoparticles, leading to the formation of aggregates. In this condition we have measured the ferrofluid AC magnetic susceptibility in parallel and perpendicular configuration of magnetic and electric fields at room temperature. The measurements in both configurations yielded a noticeable decrease in the real susceptibility values with increasing electric field intensity. The result is believed to be caused by the reduction in the total magnetic moment of the ferrofluid. This can be a consequence of the superspin interactions in the aggregates, minimizing the aggregate's energy. Finally, we highlight the necessity of NMR and small angle scattering of polarized neutrons investigations in order to obtain exact information on the magnetic structure induced by the electric forces.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 887-889
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elimination of Magnetic Nanoparticles with Various Surface Modifications from the Bloodstream in vivo
Autorzy:
Tomasovicova, N.
Khmara, I.
Koneracka, M.
Zavisova, V.
Kubovcikova, M.
Antal, I.
Kovac, J.
Muckova, M.
Kopcansky, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032816.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.50.Tt
87.85.jj
Opis:
The magnetic nanoparticles with the core diameter 10 nm stabilized by sodium oleate and bovine serum albumin in phosphate buffer have been modified by different biocompatible substances such as poly(ethylene glycol) (PEG), dextran (DEX), and polyvinylpyrrolidone (PVP). Prepared biocompatible magnetic fluids were characterized to obtain the particle size distribution using scanning electron microscopy and the dynamic light scattering method. To study the elimination of different modified magnetic nanoparticles from bloodstream, the biocompatible samples were applied intravenously to the mice bloodstream with further blood specimens collecting in given time intervals. Magnetic moment of the lyophilized blood samples was measured by SQUID magnetometer. Time dependence of magnetic moment of magnetic nanoparticles and magnetic nanoparticles modified by DEX, PEG and PVP normalized to the Fe₃O₄ showed that the circulation time of magnetic nanoparticles in the bloodstream depends on the substance used for modification. The unmodified magnetic nanoparticles were trapped by reticuloendothelial system within 1 h while magnetic nanoparticles modified by DEX, PEG and PVP circulated in blood up to 3 h.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1159-1161
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Structural Characterization of Ni-Ti-Zr Metallic Glass
Autorzy:
Katuna, Yu.
Lisnichuk, M.
Saksl, K.
Girman, V.
Gamcová, J.
Balga, D.
Ďurišin, M.
Kováč, J.
Sovák, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032136.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Kj
68.37.Ma
68.37.Lp
Opis:
Metallic glasses, in contrast to its crystalline counterparts, exhibit unique mechanical and structural properties, which make them attractive for practical applications. Especially Ni-Ti-Zr metallic glass is a promising alloy for micromechanical systems because of its known shape memory properties. Shape memory effect is connected with structural phase transformation. In this paper, the ambient-temperature-structure of Ni-Ti-Zr metallic glass is investigated using transmission electron microscopy and synchrotron X-ray diffraction, the surface and chemical analysis is documented using scanning electron microscopy. Thermal stability of the alloy has been determined using differential scanning calorimetry.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 750-752
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Differentiation of Native and Reconstructed Ferritin using the MRI Gradient Echo Pulse Sequence
Autorzy:
Balejcikova, L.
Strbak, O.
Baciak, L.
Kovac, J.
Masarova, M.
Krafcik, A.
Kopcansky, P.
Dobrota, D.
Frollo, I.
Powiązania:
https://bibliotekanauki.pl/articles/1032829.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.Ej
83.85.Fg
87.61.-c
87.64.Cc
87.85.jf
Opis:
Ferritin is a biological iron storage biomacromolecule, consisting of a spherical protein shell (apoferritin) and mineral iron core. It plays a crucial role in the pathological processes of disrupted iron homeostasis followed by iron accumulation, linked with various disorders (e.g. neuroinflammation, neurodegeneration, cirrhosis, cancer, etc.) In vitro reconstructed ferritin, with the assistance of a non-invasive magnetic resonance imaging technique, has the potential to become a suitable biomarker of these pathological processes. Through gradient echo pulse sequencing, we were able to clearly distinguish between native (physiological) and reconstructed/iron-overloaded (pathological) ferritin, which can serve as a starting point for the development of a method for their differentiation. Such method is necessary for the early diagnosis of iron-based diseases.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1093-1095
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Morphology on Magnetic Properties of Magnetosomes
Autorzy:
Hashim, A.
Molčan, M.
Kovač, J.
Varchulová, Z.
Gojzewski, H.
Makowski, M.
Kopčansky, P.
Tomori, Z.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1428653.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.65.Cb
51.60.+a
75.30.Gw
75.50.Tt
75.60.Nt
75.60.Ej
Opis:
Cultivation process was changed three times. The culture medium was enriched by more amount ferric quinate (FQ magnetosomes sample) and more amounts Wolfe's vitamin solution (WVS magnetosomes sample) comparing to normal culture medium (NP magnetosomes sample). NP sample of magnetosomes shows zero coercivity and behaves superparamagnetically. The increase of coercivity (6.5 Oe for WVS and 20 Oe for FQ) may be caused by higher value of shape anisotropy and reveals stronger magnetic correlations between particles of magnetite chains.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1250-1252
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-50 z 55

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