Alien Registration- Drouin, Rev. Cerve Francois M. (Lewiston, Androscoggin County)

https://digitalmaine.com/alien_docs/22213/thumbnail.jp

Probing carrier behaviour at the nanoscale in gallium nitride using low voltage cathodoluminescence

The increasing application of GaN in blue and UV light emitting diodes and lasers has generated considerable interest in its optical and electrical properties. These optical devices exhibit extremely high emission efficiencies despite the presence of a very high concentration of threading dislocations (108 1010 cm-2) that act as non-radiative recombination channels. This perceived contradiction can be been explained by small (< 100 nm) carrier diffusion lengths which effectively negate the effect of the threading dislocations on the radiative recombination efficiency. These short exciton and minority carrier diffusion lengths in GaN can be explored by cathodoluminescence (CL) microscopy and spectroscopy using a SEM equipped with a Schottky field emission gun operating at 1 kV

Depletion layer imaging using a gaseous secondary electron detector in an environmental scanning electron microscope

Abstract : We present a method for imaging depletion layers using the gaseous secondary electron detector (GSED) employed in environmental scanning electron microscopes. GSED images of a p-np-n junction were obtained from a Si P+PNP+PN power diode. Behavior of the junction contrast as a function of imaging conditions is unrelated to reported GSED contrast formation mechanisms [ A. L. Fletcher, B. L. Thiel, and A. M. Donald, J. Phys. D 30, 2249 (1997)]. Optimum imaging conditions are presented, and the contrast behavior is interpreted in terms of a previously unreported induced current component in GSED images. The presented technique is unique as it will enable imaging of depletion layers in uncoated semiconductor/oxide devices in controlled gaseous environments at elevated specimen temperatures

Probing Carrier Behavior at the Nanoscale in Gallium Nitride using Low Voltage Cathodoluminescence

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Response to "Comment on 'Carrier recombination near threading dislocations in GaN epilayers by low voltage cathodoluminescence'" [Appl. Phys. Lett. 97, 166101 (2010)]

Abstract : The authors are aware that there are number of theoretical models available to simulate cathodoluminescence (CL) contrast as a function of the distance, r, from a nonradiative defect. In our letter1 a simple expression, C(r)=C0 exp(−r/L)C(r)=C0 exp(−r/L), was chosen to compare the diffusion length, L, from GaN samples with different n-doping levels over a range of low electron beam energies. This approach is widely used in other studies of CL dislocation contrast as pointed out in the comment on the letter and it was found to provide an acceptable fit to the experimental CL contrast data

A Learner-Centered Technique and Clinical Reasoning, Reflection, and Case Presentation Attributes in Athletic Training Students

CONTEXT: Providing opportunities to develop clinical decision-making skills, including clinical reasoning, is an important aspect of clinical education. The learner-centered technique of summarizing the history and findings, narrowing the differential, analyzing the differential, probing the instructor about uncertainties, plan management, and selecting an issue for self-directed study (SNAPPS) is used in medicine to express clinical reasoning. OBJECTIVE: To investigate the effects of SNAPPS on the clinical reasoning, reflection, and 4 case presentation attributes (length, conciseness, case summary, and expression of clinical reasoning) in athletic training students. DESIGN: Randomized controlled clinical trial. SETTING: Three undergraduate programs accredited by the Commission on Accreditation of Athletic Training Education. PATIENTS OR OTHER PARTICIPANTS: We randomly assigned 38 athletic training students (17 men, 21 women; age = 21.53 ± 1.18 years, grade point average = 3.25 ± 0.31) who had completed at least 1 year of clinical education and all orthopaedic evaluation coursework to the SNAPPS group or the usual and customary group using a stratification scheme. INTERVENTION(S): The SNAPPS group completed four 45-minute clinical reasoning and case presentation learning modules led by an investigator to learn the SNAPPS technique, whereas the usual and customary group received no formal instruction. Both groups audio recorded all injury evaluations performed over a 2-week period. MAIN OUTCOME MEASURES: Participants completed the Diagnostic Thinking Inventory and Reflection in Learning Scale twice. Case presentations were analyzed for 4 attributes: length, conciseness, case summary, and expression of clinical reasoning. RESULTS: Case presentations were longer (t(18.806) = −5.862, P < .001) but were more concise (t(32) = 11.297, P < .001) for the SNAPPS group than for the usual and customary group. The SNAPPS group performed better on both the case summary subscale (t(32) = 2.857, P = .007) and the clinical reasoning subscale (t(25.773) = −14.162, P < .001) than the other group. We found a time effect for Diagnostic Thinking Inventory scores (F(1,34) = 6.230, P = .02) but observed no group effects (F(1,34) = 0.698, P = .41) or time-by-group interaction (F(1,34) = 1.050, P = .31). The Reflection in Learning Scale scores analysis revealed no group-by-time interaction (F(1,34) = 1.470, P = .23) and no group (F(1,34) = 3.751, P = .06) or time (F(1,34) = 0.835, P = .37) effects. CONCLUSIONS: The SNAPPS is an effective and feasible clinical education technique for case presentations. This learner-centered technique provides the opportunity for the expression of clinical reasoning skills

Le modèle en questions

Derrière la multiplicité des emplois du terme de modèle, peut-on supposer que se cache un concept unique, ou doit-on en rester à un constat d'hétérogénéité ? Cette question a été débattue au cours d'un séminaire dont le texte qui suit se fait l'écho. Sans vouloir aboutir à une définition unique et fermée, cette réflexion tente de trouver des cohérences au milieu des contradictions. L'analyse d'un modèle en biologie illustre un certain nombre de caractères mis à jour dans cette étud