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Wyszukujesz frazę "68.37.Vj" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
X-ray diffraction microstructural analysis of swelling by ethylene glycol in two reference clay minerals
Autorzy:
García Tomás, F.
Kojdecki, M.
Pardo, P.
Ibańez, R.
Álvarez Larena, A.
Bastida, J.
Powiązania:
https://bibliotekanauki.pl/articles/1152823.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.Vj
61.72.Dd
Opis:
Kaolinite and montmorillonite are two clay minerals with different structures: dioctahedral 1:1 without layer charge and dioctahedral 2:1 with low layer charge. X-ray-diffraction microstructural analysis of two fractions of two reference clays (with kaolinite or montmorillonite) from the Clay Minerals Society Source Clay Repository were performed by the Voigt function method to provide microstructural data not available in the baseline studies of this Repository. A rough agreement was found between crystallite sizes determined from X-ray diffraction patterns and from images by field-emission scanning electron microscopy. In addition, the influence of swelling by ethylene-glycol on crystallite size was studied by the mentioned method. Two factors were found to affect the crystallite size variation in ethylene-glycol-treated clay minerals: (i) the increase of the unit cell in [001] direction due to the interlayer absorption of ethylene glycol molecules in the case of swelling minerals and (ii) the physisorption at the surfaces of the crystallites. Both effects operate in the case of montmorillonite, whereas just the latter one is expected in kaolinite.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 876-879
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrogen-Induced Changes in Palladium Surface Structure: Field Ion Microscopy Study
Autorzy:
Tomaszewska, A.
Stępień, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1811502.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.-d
68.37.Vj
79.70.+q
Opis:
In this work the field ion microscopy technique was used in order to examine hydrogen-induced changes in palladium surface structure in the context of surface palladium hydrides formation. The goal of the study is to determine the crystallographic planes on which the particles of interest are formed with greatest intensity. Employing a method which consists in finding the differences in the brightness of field ion microscopy images we found that the structures of palladium surface hydrides, the size of which varies from 1 to 30 nm, develop mainly on {110} planes of palladium.
Źródło:
Acta Physica Polonica A; 2008, 114, S; S-135-S-140
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Size Effect in Photofield Emission
Autorzy:
Radoń, T.
Powiązania:
https://bibliotekanauki.pl/articles/1535667.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.Vj
73.20.At
79.70.+q
Opis:
This paper contains a short reconsideration and explanation of the effect of photofield emission-current deviations. Theoretical considerations of the dynamic image-potential barrier did not yield a satisfactory result. A certain interpretation, suggested a few years ago, indicated that the photocurrent deviations reflect quantum-well states of the outer microcrystal of the apex of the field emitter. This point of view covers a variety of photocurrent deviations observed both for the integral field emission and for the one from a single crystal face as well as from a barium covered field emitter. It also includes the deviations observed for different photon energies and the deviations containing different apparent frequencies.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 596-599
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diffusion of Potassium on the W(112) Plane Preadsorbed by Ni Atoms: Field Emission Current Fluctuations - Autocorrelation Study
Autorzy:
Biernat, T.
Błaszczyszyn, R.
Kleint, Ch.
Powiązania:
https://bibliotekanauki.pl/articles/2027391.pdf
Data publikacji:
2001-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.70.+q
68.37.Vj
68.43.Jk
05.40.Ca
Opis:
Diffusion of potassium adsorbate on the W(112) plane with preadsorbed nickel was investigated by means of the autocorrelation function of field emission current fluctuations. A comparison of the experimental autocorrelation function with that of a theoretical calculation by Gesley and Swanson gives the surface diffusion coefficient of potassium. From its temperature dependence the diffusion activation energy at several Ni pre-coverages for a constant potassium coverage (Θ$\text{}_{K}$=0.4) is derived. The dependence of the activation energy for potassium surface diffusion on the nickel coverage - first reduction and then an increase with increasing Ni coverage - is observed. This is in agreement with the results obtained from the spectral analysis of the field emission current fluctuations of the same system. The decrease is understood to be a result of the smoothing effect caused by Ni atoms on the W(112) plane.
Źródło:
Acta Physica Polonica A; 2001, 99, 6; 665-672
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diffusion of Palladium on Tantalum Microcrystal
Autorzy:
Antczak, G.
Błaszczyszyn, R.
Powiązania:
https://bibliotekanauki.pl/articles/2035655.pdf
Data publikacji:
2003-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.70.+q
68.37.Vj
68.43.Jk
05.40.Ca
Opis:
Surface diffusion of palladium,Θ=2 ML, on a tantalum microcrystal was studied by means of field electron emission microscopy within the temperature range 665-790 K. The observed sharp moving boundary-diffusion proceeds with an activation energy ranging from 1.25 to 1.7 eV/atom, depending on the crystallographic direction.
Źródło:
Acta Physica Polonica A; 2003, 103, 1; 57-65
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and texture evolution in the welded semi-austenitic PH steel after the heat treatment
Autorzy:
Ziewiec, A.
Witkowska, M.
Zielińska-Lipiec, A.
Powiązania:
https://bibliotekanauki.pl/articles/1153207.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Vj
81.40.Gh
81.40.Ef
68.37.Lp
Opis:
The aim of this study was to reveal the influence of the heat treatment after welding of 17-7PH (X7CrNiAl17-7) steel on the microstructure evolution and the texture of the welds. Microstructure investigation carried out by light microscopy and transmission electron microscopy showed that the austenite and δ ferrite coexist in as-welded condition. Annealing at the temperature range between 400°C and 620°C after welding causes small changes in the microstructure and the hardness of the welds increases. Heat treatment at 760°C for 1 h resulted in the partial destabilization of the austenite. Aging after destabilization leads to tempering of the martensite: first the hardness increases and then decreases. The maximum hardness is observed when the ageing temperature reaches 510°C. XRD studies confirmed the presence of the two phases: δ ferrite and austenite. Annealing at 400°C/1 h and 550°C/1 h results in changes of the intensities for individual peaks derived from austenite and ferrite. The calculated ratios of peak intensity were compared with the intensities of the reference sample. The differences in intensities suggested strong texture of the material.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 956-959
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of σ-phase formation on long-term durability of welding joints in SUPER 304H steels
Autorzy:
Horváth, J.
Král, P.
Janovec, J.
Powiązania:
https://bibliotekanauki.pl/articles/1112347.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.70.Jb
68.37.Ma
81.30.Mh
81.20.Vj
62.20.mj
Opis:
Article presents results on the analysis of secondary phases formed in the medium-term static isothermal ageing welding joints of a SUPER 304H (675°C/2×10⁴ h). The investigations of the precipitates were focused on the occurrence of σ-phase because its formation leads to significant deterioration of mechanical properties. The microstructure was investigated on microscopic level by scanning/transmission electron microscopy. The distribution and quantification of brittle σ-phase were studied on macroscopic level by color etching method using light optical microscopy. The effect of microstructural changes (σ-phase formation) on the impact strength of an aged base material was investigated. For comparison impact tests on received state material were also performed. The results showed that long-term ageing led to the significant reduction of impact strength as a result of the formation of the σ-phase. It was found that the σ-phase distribution is influenced by welding process. The influence of brittle σ-phase on long-term durability of the degraded steel regarding its insufficient impact strength has been discussed.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 960-962
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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