Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Physics
Coursenetworking And Community: Linking Online Discussion Networks And Course Success, Adrienne L. Traxler, Andrew Gavrin, Rebecca Lindell
Coursenetworking And Community: Linking Online Discussion Networks And Course Success, Adrienne L. Traxler, Andrew Gavrin, Rebecca Lindell
Physics Faculty Publications
Large introductory science courses are isolating for many students, and reducing this isolation is an important factor for student retention in college. Active learning courses often build community among students as an explicit goal, but many commuter or non-traditional students have limited on-campus time. Online discussion forums provide one tool for engaging students with each other outside of class time. This study uses social network analysis with forum data from an introductory physics course to examine students' positions in the class discussion network and link it to their final course grades. We find that, contrary to expectations, there is no …
Non-Traditional Students' Conceptual Scores And Network Centrality In Scale-Up Classrooms, Emily N. Sandt, Adrienne L. Traxler
Non-Traditional Students' Conceptual Scores And Network Centrality In Scale-Up Classrooms, Emily N. Sandt, Adrienne L. Traxler
Physics Faculty Publications
As classrooms transition from traditional to cooperative learning environments, questions about the details of these environments effectiveness are posed. Does this model equally benefit all students? How do nontraditional (NT) students' gains in conceptual knowledge compare to those of traditional (Trad) students in these classrooms? Do NT students' social differences (i.e. age, employment status, family life, etc.) affect the amount of learning they do in the course or their tendency to form collaborative ties with other students? In three sections of SCALE-UP introductory calculus-based physics, we collected social network survey data about student connections and used the Force Concept Inventory …
Photoexcited Carrier Trapping And Recombination At Fe Centers In Gan, T. K. Uždavinys, S. Marcinkevičius, J. H. Leach, K. R. Evans, David C. Look
Photoexcited Carrier Trapping And Recombination At Fe Centers In Gan, T. K. Uždavinys, S. Marcinkevičius, J. H. Leach, K. R. Evans, David C. Look
Physics Faculty Publications
Fe doped GaN was studied by time- resolved photoluminescence (PL) spectroscopy. The shape of PLtransients at different temperatures and excitation powers allowed discrimination between electron and hole capture to Fe3+ and Fe2+ centers, respectively. Analysis of the internal structure of Fe ions and intra-ion relaxation rates suggests that for high repetition rates of photoexciting laser pulses the electron and hole trapping takes place in the excited state rather than the ground state of Fe ions. Hence, the estimated electron and hole capture coefficients of 5.5 × 10−8 cm3/s and 1.8 × 10−8 cm3/s should be attributed to excited Fe3+ and …
Ultrafast Saturation Of Electronic-Resonance-Enhanced Coherent Anti-Stokes Raman Scattering And Comparison For Pulse Durations In The Nanosecond To Femtosecond Regime, Anil K. Patnaik, Sukesh Roy, James R. Gord
Ultrafast Saturation Of Electronic-Resonance-Enhanced Coherent Anti-Stokes Raman Scattering And Comparison For Pulse Durations In The Nanosecond To Femtosecond Regime, Anil K. Patnaik, Sukesh Roy, James R. Gord
Physics Faculty Publications
The saturation threshold of a probe pulse in an ultrafast electronic-resonance-enhanced (ERE) coherent anti-Stokes Raman spectroscopy (CARS) configuration is calculated. We demonstrate that while the underdamping condition is a sufficient condition for saturation of ERE-CARS with the long-pulse excitations, a transient gain must be achieved to saturate the ERE-CARS signal for the ultrafast probe regime. We identify that the area under the probe pulse can be used as a definitive parameter to determine the criterion for a saturation threshold for ultrafast ERE-CARS. From a simplified analytical solution and a detailed numerical calculation based on density-matrix equations, the saturation threshold of …
Improved Sensitivity Mems Cantilever Sensor For Terahertz Photoacoustic Spectroscopy, Ronald A. Coutu Jr., Ivan Medvedev, Douglas T. Petkie
Improved Sensitivity Mems Cantilever Sensor For Terahertz Photoacoustic Spectroscopy, Ronald A. Coutu Jr., Ivan Medvedev, Douglas T. Petkie
Physics Faculty Publications
In this paper, a microelectromechanical system (MEMS) cantilever sensor was designed, modeled and fabricated to measure the terahertz (THz) radiation induced photoacoustic (PA) response of gases under low vacuum conditions. This work vastly improves cantilever sensitivity over previous efforts, by reducing internal beam stresses, minimizing out of plane beam curvature and optimizing beam damping. In addition, fabrication yield was improved by approximately 50% by filleting the cantilever’s anchor and free end to help reduce high stress areas that occurred during device fabrication and processing. All of the cantilever sensors were fabricated using silicon-on-insulator (SOI) wafers and tested in a custom …