5,230 research outputs found
Hall effect study of electron irradiated Si(Li)
Measurement of the Hall coefficient as a function of temperature between 15 and 300 K allows the separate determination of donor and acceptor concentrations in silicon samples which were irradiated at 240 K by 1-MeV electrons and then thermally annealed at 300 K. In both lithium- and phosphorus-doped silicon irradiation increased the acceptor concentration and decreased the donor concentration due to the formation of vacancy donor pairs. Annealing did not change either concentration in phosphorus-doped silicon and caused both concentrations to decrease in silicon doped with moderate amounts of lithium. In addition to this, in both lithium- and phosphorus-doped silicon the concentration and energy level of the A center were measured at each point in the sample's history. This experiment was limited to float-zoned silicon doped with less than 6 x 10 to the 14th power donors per cu cm
Crossovers: Digitalization and literature in foreign language education
Digitalization produces increasingly multimodal and interactive literary forms. A major challenge for foreign language education in adopting such forms lies in deconstructing discursive borders between literary education and digital education (romance of the book vs. euphoric media heavens), thereby crossing over into a perspective in which digital and literary education are intertwined. In engaging with digital literary texts, it is additionally important to consider how different competencies and literary/literacy practices interact and inform each other, including: (1) a receptive perspective: reading digital narratives and digital literature can become a space for literary aesthetic experience, and (2) a productive perspective: learners can become “produsers” (Bruns, 2008) of their own digital narratives by drawing on existing genre conventions and redesigning “available designs” (New London Group, 1996). Consequently, we propose a typology of digital literatures, incorporating functional, interactive and narrative aspects, as applied to a diverse range of digital texts. To further support our discussion, we draw on a range of international studies in the fields of literacies education and 21st century literatures (e.g., Beavis, 2010; Hammond, 2016; Kalantzis & Cope, 2012; Ryan, 2015) and, in turn, explore trajectories for using concrete digital literary texts in the foreign language classroom
Book review: copyright and E-learning: a guide for practitioners, 2nd ed. by Jane Secker with Chris Morrison
In Copyright and E-Learning, A Guide for Practitioners, Jane Secker and Chris Morrison provide guidance to educational practitioners working with copyright content. While the book is particularly of use to those in the HE sector, this guide offers a holistic, timely and useful overview of the most pertinent copyright issues affecting education today, writes Emily Stannard
Additional extensions to the NASCAP computer code, volume 1
Extensions and revisions to a computer code that comprehensively analyzes problems of spacecraft charging (NASCAP) are documented. Using a fully three dimensional approach, it can accurately predict spacecraft potentials under a variety of conditions. Among the extensions are a multiple electron/ion gun test tank capability, and the ability to model anisotropic and time dependent space environments. Also documented are a greatly extended MATCHG program and the preliminary version of NASCAP/LEO. The interactive MATCHG code was developed into an extremely powerful tool for the study of material-environment interactions. The NASCAP/LEO, a three dimensional code to study current collection under conditions of high voltages and short Debye lengths, was distributed for preliminary testing
Additional extensions to the NASCAP computer code, volume 2
Particular attention is given to comparison of the actural response of the SCATHA (Spacecraft Charging AT High Altitudes) P78-2 satellite with theoretical (NASCAP) predictions. Extensive comparisons for a variety of environmental conditions confirm the validity of the NASCAP model. A summary of the capabilities and range of validity of NASCAP is presented, with extensive reference to previously published applications. It is shown that NASCAP is capable of providing quantitatively accurate results when the object and environment are adequately represented and fall within the range of conditions for which NASCAP was intended. Three dimensional electric field affects play an important role in determining the potential of dielectric surfaces and electrically isolated conducting surfaces, particularly in the presence of artificially imposed high voltages. A theory for such phenomena is presented and applied to the active control experiments carried out in SCATHA, as well as other space and laboratory experiments. Finally, some preliminary work toward modeling large spacecraft in polar Earth orbit is presented. An initial physical model is presented including charge emission. A simple code based upon the model is described along with code test results
Effect of high and low glycaemic index recovery diets on intramuscular lipid oxidation during aerobic exercise
Intramyocellular lipid (IMCL) and plasma NEFA are important skeletal muscle fuel sources. By raising blood insulin concentrations, carbohydrate ingestion inhibits lypolysis and reduces circulating NEFA. We hypothesised that differences in the postprandial glycaemic and insulin response to carbohydrates (i.e. glycaemic index; GI) could alter NEFA availability and IMCL use during subsequent exercise. Endurance-trained individuals (n 7) cycled for 90 min at 70 % V?O2peak and then consumed either high GI (HGI) or low GI (LGI) meals over the following 12 h. The following day after an overnight fast, the 90 min cycle was repeated. IMCL content of the vastus lateralis was quantified using magnetic resonance spectroscopy before and after exercise. Blood samples were collected at 15 min intervals throughout exercise and analysed for NEFA, glycerol, glucose, insulin, and lactate. Substrate oxidation was calculated from expired air samples. The 90 min cycle resulted in >2-fold greater reduction in IMCL in the HGI trial (3·5 (sem 1·0) mm/kg wet weight) than the LGI trial (1·6 (sem 0·3) mm/kg wet weight, P < 0·05). During exercise, NEFA availability was reduced in the HGI trial compared to the LGI trial (area under curve 2·36 (sem 0·14) mEq/l per h v. 3·14 (sem 0·28) mEq/l per h, P < 0·05 respectively). No other differences were significant. The findings suggest that HGI carbohydrates reduce NEFA availability during exercise and increase reliance on IMCL as a substrate source during moderate intensity exercise
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