Introduction to Positron Annihilation

Hautojärvi, P.; Vehanen, A.

doi:10.1007/978-3-642-81316-0_1

Cited by 128 publications

(142 citation statements)

References 44 publications

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“…However, in terms of the detailed variation of 7 m, the present result is different from that observed in simple metals and alloys. It is known (Hautojarvi 1979) that in simple metals and alloys, with increasing deformation t, the mean positron lifetime 7 m and the Doppler broadening parameters H or S increase rapidly under low deformation, change very slowly in the deformation range 5-10%, and reach saturation above 10-20%; for example, the variation of 7 m in the deformed a-Fe (Brabander et aZ. 1982) (see Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Positron annihilation lifetime spectroscopy (PALS) has been used successfully to investigate defects in many metals and alloys (Hautojarvi 1979;Brandt and Dupasquier 1983). Perhaps due to complexity, the earlier positron annihilation studies on deformation defects were limited mainly to simple metals and alloys and did not look at complex polycrystalline materials.…”

Section: Introductionmentioning

confidence: 99%

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Positron Annihilation Study of Deformation in a Two-phase (α+β) Cu - Zn Alloy

Tang¹,

Li²

1996

Aust. J. Phys.

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Positron lifetimes have been measured as a function of the degree of deformation E in a two-phase (0+11) Cu-Zn alloy. In this alloy the increase of the mean positron lifetime Tm with E is slower and the saturation effect occurs at a larger deformation than that in most simple metals and alloys. With increasing E the positron lifetime parameters T1 II and 12 exhibit a rise or fall near E ~ 4% and 35%, and they change slowly for 4% < E < 35%. These results are explained by the special structure of the a and 11 phases and the particular deformation mechanism in this alloy.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Positron Annihilation Study of Deformation in a Two-phase (α+β) Cu - Zn Alloy

Tang¹,

Li²

1996

Aust. J. Phys.

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“…Two states are known: parapositronium (life of about 125E-12 s), and orthopositronium (life 142E-9 s). Positronium has been relatively well studied [26] and production channels modelled mathematically [18] [27]. Positronium has the known behaviour of producing two photons when the electron and positron have antiparallel spins (parapositronium), and three photons for parallel spins (orthopositronium).…”

Section: 3mentioning

confidence: 99%

Annihilation Mechanisms

Pons¹,

Pons²,

Pons³

2014

APR

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This paper develops an ontologically rich explanation of the inner mechanics of the annihilation process, starting from a non-local hidden-variable (NLHV) design. This explains the process in terms of the handedness of matter and antimatter, the interaction of the electron and antielectron as they approach, the collapse of their discrete force structures and their reformation into photon structures. The process is more one of remanufacture than destruction. The resulting Cordus theory successfully explains para-and ortho-positronium annihilation. It explains the different photons output, the relative difference in lifetimes, and why Bhabha scattering sometimes happens instead. The theory exposes a deeper common mechanism for annihilation, pair-creation, and bonding.

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“…The carbides of transition metal of groups IV and V group have very high hardness and relatively high superconducting transition temperature. These properties make them attractive for both theoretical investigations and technological applications [3][4][5][6][7][8][9]. Many of their desirable characteristics are critically influenced by the presence of vacancies, which occur on the non-metal sublattice.…”

Section: Introductionmentioning

confidence: 99%

“…up to 60% of the nonmetal sublattice). Thus presence of vacancies in refractory metal carbides and nitrides seem to be intrinsic properties of these compounds [4][5][6][7][8][9]. Transition metal carbides and nitrides are chemically stable and exhibit high corrosion resistance.…”

Section: Introductionmentioning

confidence: 99%

Phase transition and high pressure behavior of Zirconium and Niobium carbides

Singh¹,

Aynyas²,

Sanyal

2009

Open Physics

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Abstract:We have predicted the phase transition pressure (P T ) and high pressure behavior of Zirconium and Niobium carbide (ZrC, NbC). The high pressure structural phase transitions in ZrC and NbC has been studied by using a two body inter-ionic potential model, which includes the Coulomb screening effect, due to the semimetallic nature of these compounds. These transition metal carbides have been found to undergo NaCl (B1) to CsCl (B2)-type structural phase transition, at high pressure like other binary systems. We predict such structural transformation in ZrC and NbC at a pressure of 98GPa and 85GPa respectively. We have also predicted second order elastic constant and bulk modulus. The present theoretical work has been compared with the corresponding experimental data and prediction of LAPW and GGA and LDA theories. PACS

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Introduction to Positron Annihilation

Cited by 128 publications

References 44 publications

Positron Annihilation Study of Deformation in a Two-phase (α+β) Cu - Zn Alloy

Positron Annihilation Study of Deformation in a Two-phase (α+β) Cu - Zn Alloy

Annihilation Mechanisms

Phase transition and high pressure behavior of Zirconium and Niobium carbides

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