کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10633607 | 993046 | 2005 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Nanoporosity as quantum positron traps
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Two-semiempirical positron stationary quantum models are developed for the study of nanoporosity in a wide range of solid porous materials. The cubic and conic well potentials are considered and their geometric parameters are related to the Positron Annihilation LifeTime Spectroscopy measurements (PALS). A new resonance lifetime phenomenon is found, which enables to propose a technique to trap positrons in such sites. The free volume equations of these new models were then compared to the well-known and widely utilized Spherical Free Volume Model (SFVM) and we found remarkable differences. A strong variation of the free volume size-positron lifetime relation with the geometry involved is observed and a remarkable dependence of the electron layer thickness parameter ÎR with the hole-shape under study and with the nature of the material considered. The mathematical functions appearing in the conic case are the superposition of Bessel functions of the first kind and trigonometric functions in the cubic case. Generalized free volume diagrams were drawn and a geometrical representation of the diverse cases considered was obtained.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Optical Materials - Volume 27, Issue 7, April 2005, Pages 1286-1290
Journal: Optical Materials - Volume 27, Issue 7, April 2005, Pages 1286-1290
نویسندگان
M.V. Félix, R.A. RodrÃguez-Rojas, J. Castañeda-Contreras, R. Morones, V.M. Castaño,