Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Fe" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 426
Tytuł:
Pseudorotational Averaging of EPR Spectrum of Cu(II)O$\text{}_{5}$ Complex in YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ in Low Temperatures
Autorzy:
Stankowski, J.
Kempiński, W.
Trybuła, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1891644.pdf
Data publikacji:
1991-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.-f
74.70.Vy
76.30.Fe
Opis:
In low temperatures the condensation of oxygen was found to occur at 05 site in an elementary cell of YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ being the fifth ligand forming the CuO$\text{}_{5}$ complex around Cul copper in chain. This change of coordinantion from CuO$\text{}_{4}$ to CuO$\text{}_{5}$ is the origin of a pseudorotation related to a strong vibronic coupling of two distorted configurations: a tetragonal pyramid C$\text{}_{4v}$ and a trigonal bipyramid D$\text{}_{3h}$, which yields a pseudocubic EPR spectrum in low temperatures. The averaged spectroscopic splitting coefficient is related to a superposition of vibronically coupled orbital states |x$\text{}^{2}$ - y$\text{}^{2}$〉 and |3z$\text{}^{2}$ - r$\text{}^{2}$〉. The averaged spectrum was for the first time observed in low temperatures since the oxygen condensation in YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ at 05 site of the chain occur only when oxygen undergoing fast diffusion among the chains, gets localized with decreasing temperature. The activation energy of oxygen desorption from the 05 site is 36 K.
Źródło:
Acta Physica Polonica A; 1991, 80, 4; 571-581
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Defect Recovery in α-Fe e$\text{}^{-}$-irradiated at 300 K
Autorzy:
Dai, G. H.
Li, X. H.
Moser, P.
Moya, G.
Van Duysen, J. C.
Powiązania:
https://bibliotekanauki.pl/articles/1928989.pdf
Data publikacji:
1993-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.70.Bv
61.80.Fe
78.70.Bj
Opis:
Defect annealing recovery has been studied, by measuring positron lifetime spectra, in high-purity α-iron irradiated at 300 K with 3 MeV electrons to a fluency of 7 × 10$\text{}^{19}$ cm$\text{}^{-2}$. Vacancy clusters containing 6-10 single vacancies were observed immediately after irradiation during which they were possibly forming (the so-called "irradiation annealing"). With increasing temperature, the agglomerates continually grow in size at the expense of their concentration, giving rise to the formation of microvoids (> 15 vacancies). Also present were other types of defects, probably immobile vacancies trapped by impurity (e.g. carbon) atoms and dislocation/loops generated presumably from collapse of voids during the relatively high dose irradiation and/or the annealing. The immobile vacancies eventually became movable at around 350 K, supplying the growing clusters and thus leading to a stabilization in their concentration till around 500 K. Between 500 and 700 K, microvoids gradually evaporated, but the dislocation-associated defects were able to survive annealing at temperatures as high as 700 K. The void size and concentration and their evolution have been evaluated on the basis of both the to date theoretical and experimental studies. The temperature dependence was also, observed of positron trapping into vacancy agglomerates of various sizes.Za
Źródło:
Acta Physica Polonica A; 1993, 83, 3; 277-286
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Doppler Broadening and Positron Lifetime Measurements of Well-Characterized Sandstone and Limestone Rocks
Autorzy:
Urban, J. M.
Quarles, C. A.
Salaita, G. N.
Powiązania:
https://bibliotekanauki.pl/articles/1933548.pdf
Data publikacji:
1995-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
91.60.-x
78.70.Bj
61.80.Fe
Opis:
We measured the S parameter for samples of well-characterized rocks. Some samples were cleaned while others contained natural hydrocarbons. We also saturated some samples with oil. Preliminary results show a difference in the S parameter for sandstone and limestone samples. There is also a significant difference between samples when clean and when containing natural hydrocarbons or when saturated with light oil. We also measured the lifetime spectrum for the same samples in dry, fresh water-saturated, and brine-saturated condition. The observed lifetime spectra could be described with two or three components. While a detailed understanding of the physical processes responsible for the lifetime spectra is still under study, several interesting results have been obtained. The average lifetime is correlated with the S parameter. The porosity of the samples is correlated with the intensity of the third lifetime component. The average lifetime, as well as the second lifetime component, is systematically longer in the sandstone than limestone samples, and in water or brine-saturated samples. The intensity of the third lifetime component is generally larger in the water or brine-saturated samples.
Źródło:
Acta Physica Polonica A; 1995, 88, 1; 241-248
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Special Structures of Graphite Steels After High-Energy Electron Irradiation
Autorzy:
Alexandrova, N. M.
Powiązania:
https://bibliotekanauki.pl/articles/2011024.pdf
Data publikacji:
1999-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.80.Fe
61.82.Bg
Opis:
The effect of high-energy electron irradiation on the structure and properties of the graphite steels have been investigated. It has been shown that single- and multicycle irradiation allows the improvement of hardness and ductility (≈ twice). A partial dissolution of the graphite, carbides redistribution, and refinement of the grain size allow the formation of the favorable surface structure after irradiation.
Źródło:
Acta Physica Polonica A; 1999, 96, 2; 259-262
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and Properties of Metals
Autorzy:
Kurzydłowski, K. J.
Powiązania:
https://bibliotekanauki.pl/articles/2010997.pdf
Data publikacji:
1999-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.-x
62.20.Fe
Opis:
Metals are one of the most widely used types of engineering materials. Some of their properties, e.g. elastic constants, can be directly related to the nature of the metallic bonds between the atoms. On the other hand, macro- and microstructural features of metals, such as point defects, dislocations, grain boundaries, and second phase particles, control their yield, flow, and fracture stress. Images of microstructural elements can be obtained by modern imaging techniques. Modern computer aided methods can be further used to obtain a quantitative description of these microstructures. These methods take advantage of the progress made in recent years in the field of image processing, mathematical morphology and quantitative stereology. Quantitative description of the microstructures are used for modeling processes taking place under the action of applied load at a given temperature and test (service) environment. These model considerations can be illustrated on the example of an austenitic stainless steel, which is an important material for power generating and chemical industry. Reports recently published also show that properties of materials can be significantly modified by the effect of free surface. Examples of such situations include environmental effect on the mechanical properties of materials. Data for an austenitic stainless steel is used to discuss contribution of the free surface to the mechanical properties of metals.
Źródło:
Acta Physica Polonica A; 1999, 96, 1; 69-79
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Error estimation and adaptivity for nonlinear FE analysis
Autorzy:
Huerta, A.
Rodriguez-Ferran, A.
Diez, P.
Powiązania:
https://bibliotekanauki.pl/articles/907892.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
element skończony
finite elements
error estimation
adaptivity
nonlinearity
quality of FE solutions
damage models
Opis:
An adaptive strategy for nonlinear finite-element analysis, based on the combination of error estimation and h-remeshing, is presented. Its two main ingredients are a residual-type error estimator and an unstructured quadrilateral mesh generator. The error estimator is based on simple local computations over the elements and the so-called patches. In contrast to other residual estimators, no flux splitting is required. The adaptive strategy is illustrated by means of a complex nonlinear problem: the failure analysis of a single-edge notched beam. The quasi-brittle response of concrete is modelled by means of a nonlocal damage model.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 1; 59-70
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Mössbauer and structural study of disordered alloys Fe3-xTixAl (0 < x < 1)
Autorzy:
Brząkalik, K.
Frąckowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/148880.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Fe2TiAl Heusler phase
Fe-Ti-Al system
Mössbauer spectroscopy
Opis:
A series of the disordered Fe3-xTixAl (x = 0, 0.2, 0.45, 0.55, 0.65, 0.70, 0.75, 1) alloys obtained by arc-melting were studied. Directly after melting the samples were mechanically crashed and in that form examined by the structural and Mössbauer effect methods. The alloys were strongly disordered, but it was possible to identify, apart from Fe-bcc phase, the origins of forming such phases as Fe2TiAl Heusler phase, Fe3Al with DO3 structure, FeAl and FeTi with B2 structure and non-stechiometric Fe2Ti Laves phase with hexagonal C14 structure. For Ti concentration up to x = 0.45, the disordered Fe-bcc phase dominates. For Ti concentration from x = 0.55 to x = 1, the Fe2TiAl phase coexists with FeAl phase (for x = 0.55, 0.65) and with FeTi phase (x = 0.7 and 0.75). In a sample with the nominal Fe2TiAl composition of Fe2TiAl Heusler phase, a non-stoichiometric Fe2Ti Laves phase with hexagonal C14 structure was observed.
Źródło:
Nukleonika; 2003, 48,suppl.1; 13-16
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ab initio study of the effect of pressure on the hyperfine parameters of 57Fe in bcc phase
Autorzy:
Michalecki, T.
Deniszczyk, J.
Frąckowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/148860.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
TB-LMTO
FP-LAPW
Fe-bcc
hyperfine magnetic field
isomer shift
Opis:
In this paper the results of studies on the effect of pressure on hyperfine magnetic field (Bf) and isomer shift (IS) for Fe-bcc are presented. Two calculation methods were used: TB-LMTO (Tight Binding Linear Muffin-Tin) and FP-LAPW (Full Potential Linearized Augmented Plane Wave) and the obtained results have been compared. Both methods lead to comparable results. In the study a particular emphasis has been laid on investigations of the atomic core electrons (1s, 2s, 3s) and of the conduction electrons 4s on the Bf and IS values. The calculated values of the dIS/dlnV and dlnB /dlnV parameters give evidence of good conformity with those derived from experimental data.
Źródło:
Nukleonika; 2003, 48,suppl.1; 45-48
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrogen effect on the electronic and structural properties of Nb-Fe alloys
Autorzy:
Brzeska-Michalak, B.
Ostrasz, A.
Powiązania:
https://bibliotekanauki.pl/articles/148793.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Mössbauer spectroscopy of 57Fe
iron-niobium alloys
niobium hydrides
Opis:
The influence of hydrogen on the electronic and structural properties of Nb1-yFey alloys has been studied with 57Fe Mössbauer spectroscopy and X-ray diffraction. No ability of hydrogen to creation of the ferromagnetic properties has been observed in this system. The results clearly indicate the ß-NbH0.85÷0.77 hydride formation in place of ?-Nb phase. The quadrupole splitting and the isomer shift of the ß-NbHx subspectrum have been considered in terms of interaction between the interstitials and the Mössbauer atoms within the hydride phase.
Źródło:
Nukleonika; 2003, 48,suppl.1; 53-57
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanocrystallization studies of rapidly quenched Fe85.4-xCoxZr6.8-yNbyB6.8Cu1 (x = 0 or 42.7, y = 0 or 1) alloys
Autorzy:
Olszewski, J.
Zbroszczyk, J.
Ciurzyńska, W.
Fukunaga, H.
Wysłocki, B.
Perduta, K.
Łukiewska, A.
Młyńczyk, A.
Lelątko, J.
Świerczek, J.
Powiązania:
https://bibliotekanauki.pl/articles/148787.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Mössbauer spectra
nanocrystalline Fe-Co alloys
Opis:
The microstructure of amorphous and nanocrystalline Fe42.7Co42.7Zr6.8-xNbxB6.8Cu1 (x = 0 or 1) alloys was investigated. We have stated that the nanocrystalline samples consist of the crystalline alfa-FeCo grains about 8 nm in diameter embedded in an amorphous matrix which is rich in cobalt. From Mössbauer spectroscopy studies we have found that the crystalline alfa-FeCo phase in the nanocrystalline samples obtained by the conventional annealing is atomically ordered. Moreover, the order degree depends on the annealing time. As for the samples partially crystallized during rapid quenching, the crystalline alfa-FeCo phase is atomically disordered.
Źródło:
Nukleonika; 2003, 48,suppl.1; 49-52
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal defects in iron-based Fe-V solid solutions
Autorzy:
Chojcan, J.
Beliczyński, J.
Powiązania:
https://bibliotekanauki.pl/articles/148884.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
dilute Fe-based alloys
Mössbauer spectroscopy
thermal point defects
vacancy formation
Opis:
Room temperature 57Fe Mössbauer spectra, positron annihilation lifetime data, X-ray diffraction patterns, and energy distributions of X-rays induced by an electron beam were measured for samples of the Fe0.947V0.053 solid solution quenched from different temperatures not exceeding 1250 K, into water being at about 295 K. The data were analysed in terms of concentration of unoccupied sites in the 14-site neighbourhood of the 57Fe Mössbauer probe in the specimens. It was found that the vacancy formation enthalpy amounts to 0.8 š 0.2 eV in the materials studied.
Źródło:
Nukleonika; 2003, 48,suppl.1; 17-20
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Defect structure of Fe-Al and Fe-Al-X (X = Ni; Cu; Cr) metallic powders obtained by the self-decomposition method
Autorzy:
Hanc, A.
Frąckowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/147208.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
iron aluminides
defects
points defects
Mössbauer spectroscopy
Fe-Al
Opis:
In the present work, the Fe-Al-X (X = Cu; Ni; Cr) metallic powders produced by the self-decomposition method of the Fe-Al doped alloys were examined by Mössbauer spectroscopy. The concentration of the Fe vacancies and the Fe atoms substituting Al (Fe-AS) was determined from the intensities of the sub-spectra in the Mössbauer analysis connected with distinct Fe environments. The results have shown that nickel and copper cause an increase of vacancy concentrations in comparison with the values found for Fe-Al metallic powders, whereas chromium decreases vacancy concentrations causing a significant increase of anti-site atoms Fe-AS concentration.
Źródło:
Nukleonika; 2004, 49,suppl.3; 7-11
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First principles study of the isomer shift in Fe44M6Al50 (M = Ti, V, Cr, Co, Ni, Cu) alloys with B2 structure
Autorzy:
Michalecki, T.
Deniszczyk, J.
Frąckowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/147195.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
iron
aluminum
isomer shift
Fe-Al compound
LMTO
Opis:
The 57Fe isomer shift for Fe44M6Al50 intermetallics with the B2 structure doped with M = Ti, V, Cr, Co, Ni and Cu additions has been calculated with the tight-binding linear muffin-tin orbital (TB-LMTO) method. The effect of variation of Wigner-Seitz (WS) spheres radii on the calculated equilibrium lattice parameter (a) and isomer shift (IS) was analyzed. The calculations have shown that the 57Fe isomer shift in Fe44M6Al50 intermetallics is directly proportional to the changes in the local 4s electronic charge at Fe atoms involved by M addtions. The screening effect of 4s electrons due to changes in (4p + 3d) electronic charge is of secondary importance. The calculated dependence of the average IS on nuclear charge (Z) of the alloying metal (M) follows qualitatively the tendency observed experimentally for the M impurities in the Fe host.
Źródło:
Nukleonika; 2004, 49,suppl.3; 3-6
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid, finite element-artificial neural network model for composite materials
Zastosowanie sztucznych sieci neuronowych w modelowaniu numerycznym kompozytów przy pomocy metody elementów skończonych
Autorzy:
Lefik, M.
Powiązania:
https://bibliotekanauki.pl/articles/281993.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
artificial neural network
composite materials
self-learning FE method
Opis:
An application of Artificial Neural Networks for a definition of the effective constitutive law for a composite is described in the paper. First, a classical homogenisation procedure is directly interpreted with a use of this numerical tool. Next, a self-learning Finite Element code (FE with ANN inside) is used in the case when the effective constitutive law is deduced from a numerical experiment (substituting here a purely phenomenological approach). The new contribution to the classical self-learning procedure consists of its adaptation to a case of a non-monotonic loading (non-to-one load-deformation curve). This new ability of the method is principally due to the incremental form of the constitutive equation and the respective scheme of the neural network structure. Also an organisation of a constitutive data-base containing learning patterns is suitably modified. It is shown by examples that the training process is very quick. The error of this method is smaller, comparing to other schemes of data acquisition.
W artykule opisano zastosowanie sztucznych sieci neuronowych do określenia efektywnego związku konstytutywnego dla kompozytów. To narzędzie numeryczne użyte zostało dwojako: do bezpośredniego zapisu wyników otrzymanych w ramach klasycznej metody homogenizacji oraz do wnioskowania o własnościach efektywnych na podstawie eksperymentu numerycznego (zastępującego eksperyment rzeczywisty) wykonanego na małej, lecz reprezentatywnej próbce kompozytu. W tym drugim przypadku zastosowano schemat "samouczącego się" programu metody elementów skończonych, w którym związek konstytutywny opisany jest siecią neuronową. Schemat ten zaadaptowano tak, że może być użyty w przypadku obciążeń niemonotonicznych oraz wtedy, gdy zależność: miara odkształcenia-miara naprężenia nie jest wzajemnie jednoznaczna. Te nowe możliwości uzyskane zostały dzięki przedstawieniu związku konstytutywnego w formie przyrostowej oraz opracowania odpowiedniej do tego budowy sieci neuronowej. Schemat "samouczącego się" programu MES charakteryzuje się tym, że proces formułowania nieznanego związku konstytutywnego jest szybki, a zgodność modelu numerycznego z eksperymentem większa niż dla innych metod.
Źródło:
Journal of Theoretical and Applied Mechanics; 2004, 42, 3; 539-563
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mössbauer effect studies of Dy(Fe0.7-xNixCo0.3)2 intermetallics
Autorzy:
Jabłońska, A.
Suwalski, J.
Pszczoła, J.
Guzdek, P.
Stoch, P.
Pańta, A.
Powiązania:
https://bibliotekanauki.pl/articles/147231.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
intermetallics
crystal structure
57Fe Mössbauer effect
hyperfine interactions
Slater-Pauling curve
band structure
Opis:
Abstract A consequence of the Fe/Ni substitution in the series of Dy(Fe0.7 xNixCo0.3)2 was studied in the presented paper. The synthesis and X-ray analysis (300 K) of the Dy(Fe0.7 xNixCo0.3)2 system were performed. The cubic, MgCu2-type, Fd3m crystal structure was evidenced for this solid solution. 57Fe Mössbauer effect measurements for the system were carried out at 77 K. The obtained crystallographic lattice parameters and the hyperfine interaction data are presented. The magnetic hyperfine field values form a separate branch of the Slater-Pauling curve situated above the branch corresponding to the Dy(Fe1 xCox)2 intermetallics.
Źródło:
Nukleonika; 2004, 49,suppl.3; 85-88
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 426

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies