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- Tanvir, N. R., et al.
(författare)
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A γ-ray burst at a redshift of z~8.2
- 2009
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 461, s. 1254-1257
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Tidskriftsartikel (refereegranskat)abstract
- Long-duration γ-ray bursts (GRBs) are thought to result from the explosions of certain massive stars, and some are bright enough that they should be observable out to redshifts of z>20 using current technology. Hitherto, the highest redshift measured for any object was z = 6.96, for a Lyman-α emitting galaxy. Here we report that GRB090423 lies at a redshift of z~8.2, implying that massive stars were being produced and dying as GRBs ~630Myr after the Big Bang. The burst also pinpoints the location of its host galaxy.
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- Kulkarni, Shrinivas R., et al.
(författare)
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Study of Ti2SC under compression up to 47 GPa
- 2008
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 448:1-2, s. L1-L4
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Tidskriftsartikel (refereegranskat)abstract
- The pressure dependence of the lattice parameters of the ternary layered carbide, Ti2SC, was measured by using synchrotron radiation X-ray diffraction and a diamond anvil cell setup. The experiment was conducted at room temperature and no phase transformation was observed up to the maximum pressure of 47 GPa. The a and c lattice parameters at room condition are 3.216 (A) over circle and 11.22 (A) over circle, respectively. The bulk modulus, calculated using the Birch-Murnaghan equation of state, is 191 +/- 3 GPa, with a pressure derivative of 4.0 +/- 0.3 and that obtained by our ab initio calculations is 183 GPa, with a pressure derivative of 4.1. L Like the majority of the ternary layered carbides (MAX phases), compressibility along the c-axis was higher than that along the a-axis.
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- Phatak, Nishad A., et al.
(författare)
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Synthesis and compressive behavior of Cr2GeC up to 48 GPa
- 2008
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 463:1-2, s. 220-225
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Tidskriftsartikel (refereegranskat)abstract
- M(n+1)AX(n) compounds have gathered huge momentum because of its exciting properties. In this paper we report the synthesis of ternary layered ceramic Cr2GeC, a 211 M(n+1)AX(n) compound by hot-pressing. Scanning electron microscopy and X-ray diffraction have been employed to characterize the new synthesized phase. High-pressure compressibility of Cr2GeC were measured using diamond anvil cell and synchrotron C radiation at room temperature up to 48 GPa. No phase transformation was observed in the experimental pressure range. The bulk modulus of Cr2GeC calculated using the Birch-Murnaghan equation of state is 169 +/- 3 GPa, with K' = 3.05 +/- 0.15.
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