http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Evolution of microstructure and hardness in AZ31 alloy processed by high pressure torsion
Strá,ská,, Jitka,Janex10d,ek, Milox161,Gubicza, Jenx151,Krajx148,á,k, Tomá,x161,Yoon, Eun Yoo,Kim, Hyoung Seop Elsevier 2015 Materials science & engineering. properties, micro Vol.625 No.-
<P><B>Abstract</B></P> <P>A commercial MgAlZn alloy (AZ31) was processed by high pressure torsion (HPT) at room temperature, resulting in an extreme microstructure refinement down to the grain size of 150–250nm. The microstructure evolution during HPT was investigated by transmission electron microscopy and X-ray diffraction line profile analysis. The microhardness was measured as a function of the distance from the center of the disk and the number of HPT revolutions. The detailed analysis of dislocation contrast factors in X-ray diffraction line profiles enables to determine the population of the different slip systems as a function of the imposed strain. The influence of microstructure and defect structure evolution on microhardness is discussed in detail.</P>
<i>Kepler</i> photometry of the prototypical Blazhko star RR Lyr: an old friend seen in a new light
Kolenberg, K.,Bryson, S.,Szabó,, R.,Kurtz, D. W.,Smolec, R.,Nemec, J. M.,Guggenberger, E.,Moskalik, P.,Benkő,, J. M.,Chadid, M.,Jeon, Y.x2010,B.,Kiss, L. L.,Kopacki, G.,Nuspl, J.,Still, M Blackwell Publishing Ltd 2011 Monthly notices of the Royal Astronomical Society Vol.411 No.2
<P><B>ABSTRACT</B></P><P>We present our analysis of the long‐cadence <I>Kepler</I> data for the well‐studied Blazhko star RR Lyr, gathered during the first two quarters of the satellite’s observations and covering a total of 127 d. Besides being of great importance for our understanding of RR Lyrae stars in general, these RR Lyr data can be regarded as a case study for observations of bright stars with <I>Kepler</I>. <I>Kepler</I> can perform high‐precision photometry on targets like RR Lyr, as the saturated flux is conserved to a very high degree. The <I>Kepler</I> data on RR Lyr are revolutionary in several respects. Even with long‐cadence sampling (one measurement per 29.4 min), the unprecedented precision (< mmag) of the <I>Kepler</I> photometry allows the study of the star’s extreme light‐curve variations in detail. The multiplet structures at the main frequency and its harmonics, typical for Blazhko stars, are clearly detected up to the quintuplets. For the first time, photometric data of RR Lyr reveal the presence of half‐integer frequencies, linked to a period‐doubling effect. This phenomenon may be connected to the still unexplained Blazhko modulation. Moreover, with three observed Blazhko cycles at our disposal, we observe that there is no exact repetition in the light‐curve changes from one modulation cycle to the next for RR Lyr. This may be due to additional periodicities in the star, or to transient or quasi‐periodic changes.</P>
Gubicza, Jenx151,Jenei, Pé,ter,Nam, Kyungju,Ká,dá,r, Csilla,Jo, Hyungyung,Choe, Heeman Elsevier 2018 Materials science & engineering. properties, micro Vol.725 No.-
<P><B>Abstract</B></P> <P>Experiments were conducted to study the compression behavior of Cu-Ni foams prepared using freeze casting. The struts of the foam samples were solid-solutioned with differing Cu/Ni ratios, after which the grain size in the struts was measured using scanning electron microscopy. The compression performance of the samples was studied in both parallel and perpendicular directions to the temperature gradient, and compared with model calculations. It was confirmed that alloying increased the yield strength of the struts. The experimentally determined yield strength and elastic modulus were compared with model calculations, which revealed that the elastic modulus of the foams was lower than the values calculated from the classical compression and Gibson-Ashby models due to variation in the thickness of the struts. It was also found that the alloying of Cu and Ni improved the mechanical performance of the alloy foams because the absorbed energy for the alloys was considerably higher than that for the pure foams.</P>
Nemec, J. M.,Smolec, R.,Benkő,, J. M.,Moskalik, P.,Kolenberg, K.,Szabó,, R.,Kurtz, D. W.,Bryson, S.,Guggenberger, E.,Chadid, M.,Jeon, Y.x2010,B.,Kunder, A.,Layden, A. C.,Kinemuchi, K.,Kis Blackwell Publishing Ltd 2011 Monthly notices of the Royal Astronomical Society Vol.417 No.2
<P><B>ABSTRACT</B></P><P>Nineteen of the ∼40 RR Lyr stars in the <I>Kepler</I> field have been identified as candidate non‐Blazhko (or unmodulated) stars. In this paper we present the results of Fourier decomposition of the time‐series photometry of these stars acquired during the first 417 d of operation (Q0–Q5) of the <I>Kepler</I> telescope. Fourier parameters based on ∼18 400 long‐cadence observations per star (and ∼150 000 short‐cadence observations for FN Lyr and for AW Dra) are derived. None of the stars shows the recently discovered ‘period‐doubling’ effect seen in Blazhko variables; however, KIC 7021124 has been found to pulsate simultaneously in the fundamental and second overtone modes with a period ratio <I>P</I><SUB>2</SUB>/<I>P</I><SUB>0</SUB>∼ 0.593 05 and is similar to the double‐mode star V350 Lyr. Period change rates are derived from O − C diagrams spanning, in some cases, over 100 years; these are compared with high‐precision periods derived from the <I>Kepler</I> data alone. Extant Fourier correlations by Kovács, Jurcsik et al. (with minor transformations from the <I>V</I> to the <I>Kp</I> passband) have been used to derive underlying physical characteristics for all the stars. This procedure seems to be validated through comparisons of the <I>Kepler</I> variables with Galactic and Large Magellanic Cloud (LMC) RR Lyr stars. The most metal‐poor star in the sample is NR Lyr, with [Fe/H] =−2.3 dex; and the four most metal‐rich stars have [Fe/H] ranging from −0.6 to +0.1 dex. Pulsational luminosities and masses are found to be systematically smaller than <I>L</I> and <IMG src='/wiley-blackwell_img/equation/MNR_19317_mu1.gif' alt ='inline image'/> values derived from stellar evolution models, and are favoured over the evolutionary values when periods are computed with the Warsaw linear hydrodynamics code. Finally, the Fourier parameters are compared with theoretical values derived using the Warsaw non‐linear convective pulsation code.</P>