Zobrazeno 1 - 10
of 190
pro vyhledávání: '"H.M. Fretwell"'
Publikováno v:
Acta Physica Polonica A. 95:521-526
Different definitions of the free volumes are discussed and related to the total specific volume and to the local free (hole) volume. Positron lifetime measurements are reported for polyethylene, polytetrafluoroethylene, and CR39-copolymers. Two long
Publikováno v:
Journal of Physics: Condensed Matter. 10:10507-10515
A novel method for reconstructing the Fermi surface from experimental two-dimensional angular correlation of positron annihilation radiation (2D-ACAR) projections is proposed. In this algorithm, the 3D electron momentum-density distribution is expand
Publikováno v:
Journal of Physics: Condensed Matter. 9:10293-10299
Two-dimensional angular correlation of positron annihilation radiation (2D-ACAR) experiments provide a means of determining the electron - positron momentum density in metals and alloys over a wide range of temperatures. A difficult task regarding th
Autor:
Stephen B Dugdale, H.M. Fretwell, N. Sato, Yasunori Kubo, M A Alam, H. Harima, Maurizio Biasini
Publikováno v:
Physical Review B. 56:10192-10199
We measured the two-dimensional angular correlation of the positron annihilation radiation (2D-ACAR) on a single crystal of ${\mathrm{LaB}}_{6}$ for two projections. The anisotropies of the 2D electron-positron momentum density were very similar to t
Publikováno v:
Materials Science Forum. :161-165
Publikováno v:
Scopus-Elsevier
The first measurement of both the size and shape of the region of the Fermi surface of yttrium known as the {open_quotes}webbing{close_quotes} is reported. This particular Fermi surface feature is of considerable interest because it is very similar t
Autor:
H.M. Fretwell, Noriyuki Sato, H. Harima, M A Alam, Yasunori Kubo, Maurizio Biasini, Stephen B Dugdale
Publikováno v:
Applied Surface Science. 116:335-339
We measured the two-dimensional angular correlation of the positron annihilation radiation (2D-ACAR) on a single crystal of LaB6 for two projections. The anisotropies of the 2D electron-positron momentum density were very similar to those previously
Publikováno v:
Journal of Radioanalytical and Nuclear Chemistry Articles. 210:575-582
In this paper we present our recent positron annihilation study of the liquid»solid phase boundary for CO2 confined in nanometer pores of VYCOR glass. We find that CO2 remains liquid in the pores far below the bulk freezing temperature and there is
Publikováno v:
Journal of Radioanalytical and Nuclear Chemistry Articles. 211:173-179
The phase behaviour of carbon dioxide confined in VYCOR glass at pressures below that of the bulk triple point (∼0.51 MPa) has been investigated. The temperature at which freezing occurs appears to be pressure dependent below 0.3 MPa. As experiment
Publikováno v:
Journal of Radioanalytical and Nuclear Chemistry Articles. 211:165-171
In confined (nanometer-scale) geometry, the effects of substrate forces and finite size produce a shift of the gas ⇔ liquid phase boundary from that found in corresponding bulk. The pore transitions also show marked hysteresis. The phase behaviour