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- Varea, A., et al.
(författare)
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Tuneable magnetic patterning of paramagnetic Fe60Al40 (at. %) by consecutive ion irradiation through pre-lithographed shadow masks
- 2011
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 109:9, s. 093918-
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Tidskriftsartikel (refereegranskat)abstract
- Arrays of ferromagnetic circular dots (with diameters ranging from 225 to 420 nm) have been prepared at the surface of atomically ordered paramagnetic Fe60Al40 (at. %) sheets by means of ion irradiation through prelithographed poly(methyl methacrylate) (PMMA) masks. The cumulative effects of consecutive ion irradiation (using Ar+ ions at 1.2 x 10(14) ions/cm(2) with 10, 13, 16, 19 and 22 keV incident energies) on the properties of the patterned dots have been investigated. A progressive increase in the overall magneto-optical Kerr signal is observed for increasingly larger irradiation energies, an effect which is ascribed to accumulation of atomic disorder. Conversely, the coercivity, H-C, shows a maximum after irradiating at 16-19 keV and it decreases for larger irradiation energies. Such a decrease in H-C is ascribed to the formation of vortex states during magnetization reversal, in agreement with results obtained from micromagnetic simulations. At the same time, the PMMA layer, with an initial thickness of 90 nm, becomes progressively thinned during the successive irradiation processes. After irradiation at 22 keV, the remaining PMMA layer is too thin to stop the incoming ions and, consequently, ferromagnetism starts to be generated underneath the nominally masked areas. These experimental results are in agreement with calculations using the Monte-Carlo simulation Stopping Range of Ions in Matter software, which show that for exceedingly thin PMMA layers Ar+ ions can reach the Fe60Al40 layer despite the presence of the mask.
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| 4. |
- Haynes, John E., et al.
(författare)
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Preservice generalist teachers enlightened approach to teaching Physical Education through Teacher Biography
- 2016
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Ingår i: Australian Journal of Teacher Education. - : Edith Cowan University. - 1835-517X. ; 41:3, s. 21-38
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a new learning experience, which was introduced following an examination of the literature regarding preservice primary school teachers' (PPST) notions of their past experience in Physical Education (PE) (Elliott 2013). PPSTs were given the opportunity to recognise, reflect, interrogate and reframe a critical incident from their schooling in PE or Sport. This exercise was designed to enlighten students about their own schooling and the potential impact this event may have on pre-conceived ideas and opinions about teaching PE. Students (N=214) enrolled in off and on campus mode, of a preservice teacher education program in a university located in regional NSW, were asked to provide information about, and to analyse, an incident, either positive or negative that occurred in PE or Sport during their primary or secondary school years. In addition, students were encouraged to reframe the incident and to seek out alternative actions that could have influenced the outcome. The aim was to encourage reflection about how preconceived notions pertaining to PE might be dealt within their present position as a preservice teacher. The PPSTs scripts were analysed using the Leximancer text mining software (Smith, 2000). Findings from the analysis provided themes and concepts, which suggest a similarity for both, off and on campus, males and females. However, there are some subtle differences between the cohorts that may be due to age or experience.
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| 5. |
- Tilly, Nina, et al.
(författare)
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Comparison of Monte Carlo calculated electron slowing-down spectra generated by 60Co gamma-rays, electrons, protons and light ions
- 2002
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 47:8, s. 1303-19
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Tidskriftsartikel (refereegranskat)abstract
- When analysing the factors affecting the relative biological effectiveness (RBE) of different radiation qualities, it is essential to consider particularly the low-energy slowing-down electrons (around 100 eV to 1 keV) since they have the potential of inflicting severe damage to the DNA. We present a modified and extended version of the Monte Carlo code PENELOPE that enables scoring of slowing-down spectra. mean local energy imparted spectra and average intra-track nearest-neighbour energy deposition distances of the secondary electrons generated by different radiation qualities, such as electrons, photons, protons and light ions in general. The resulting spectra show that the low-linear energy transfer (LET) beams, 60Co gamma-rays and electrons with initial energies of 0.1 MeV and higher, have as expected approximately the same electron slowing-down fluence per unit dose in the biologically important low-energy interval. Consistent with the general behaviour of the RBE of low-energy electrons, protons and light ions, the low-energy electron slowing-down fluence per unit dose is larger than for low-LET beams, and it increases with decreasing initial projectile energy.
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