8,138 research outputs found
Self-consistent solutions to the intersubband rate equations in quantum cascade lasers: Analysis of a GaAs/AlxGa1-xAs device
The carrier transition rates and subband populations for a GaAs/AlGaAs quantum cascade laser
operating in the mid-infrared frequency range are calculated by solving the rate equations describing
the electron densities in each subband self-consistently. These calculations are repeated for a range
of temperatures from 20 to 300 K. The lifetime of the upper laser level found by this self-consistent
method is then used to calculate the gain for this range of temperatures. At a temperature of 77 K,
the gain of the laser is found to be 34 cm(-1)/(kA/cm(-2)), when only electron–longitudinal-optical
phonon transitions are considered in the calculation. The calculated gain decreases to 19.6
cm(-1)/(kA/cm(-2)) when electron–electron transition rates are included, thus showing their
importance in physical models of these devices. Further analysis shows that thermionic emission
could be occurring in real devices. © 2001 American Institute of Physics
Artificial gravity spin deployment system Patent
Development of method for producing artificial gravity in manned spacecraf
Characterization of silicon dioxide for a capacitance-type meteoroid penetration detector
Fabrication and testing of large area metal oxide silicon capacitors for micrometeoroid counting in spac
Stark ladders as tunable far-infrared emitters
A superlattice of GaAs/Ga(1 – x)Al(x)As quantum wells forms a Stark ladder under the influence of a perpendicular electric field. A two level incoherent emitter system, formed by radiative intersubband transitions between adjacent wells, is investigated as a tunable far-infrared radiation source. Intersubband transition rates are calculated at 4, 77, and 300 K for applied fields from 0 to 40 kV cm(–1). It is shown that the quantum efficiency of the radiative emission reaches a maximum at low temperatures for a field of 32 kV cm(–1). Under these conditions the emission wavelength is 38 µm with an estimated power output of 1.1 mW. © 1998 American Institute of Physics
The development of radiation resistant insulating layers for planar silicon technology, 29 May 1968 - 28 June 1969
Ion implantation method for improving radiation resistance of thermal oxides on silico
Research based co-teaching practices and their realization in the New Jersey high school classroom
This qualitative research study reviews co-teaching practices suggested to high school educators by their professional literature. Through a systematic analysis of published studies on the topic, a comprehensive list of suggested co-teaching practices from the past ten years was created. The study then explored the realization of these practices in the high school co-teaching classroom through surveys of 61 high school co-teachers in New Jersey. Both phases of this study assisted with the identification of opportunities for improving co-teaching practices, professional development on co-teaching, and instructional pedagogy
Isocrinid crinoids from the late Cenozoic of Jamaica
Eight species of isocrinines have been documented from the Lower Cretaceous to Pleistocene of Jamaica. New finds include a second specimen of a Miocene species from central north Jamaica, previously regarded as Diplocrinus sp. but reclassified as Teliocrmus? sp. herein. Extant Teliocrinus is limited to the Indian Ocean, although Miocene specimens have been recorded from Japan, indicating a wider distribution during the Neogene. One locality in the early Pleistocene Manchioncal Formation of eastern Jamaica has yielded three species of isocrinine, Cenocrinus asterius (Linné), Diplocrinus maclearanus (Thomson) and Neocrinus decorus Thomson. These occur in association with the bourgueticrinine Democrinus sp. or Monachocrinus sp. These taxa are all extant and suggest a minimum depositional depth for the Manchioneal Formation at this locality of about 180 m. This early Pleistocene fauna represents the most diverse assemblage of fossil crinoids documented from the Antillean region.
RÉSUMÉ
Huit espèces d'isocrinines de la période du Cretacé infeérieur au Pleéstocene de la Jamatque ont été documentés. Les nouvelles découvertes comprennent un deuxième spécimen d'unc espèce du Miocène du nord central de la Jamaique, auparevant considered comme l'espèce Diplocrinus, mais reclassified en tant que Teliocrinus? aux présentes. Le Teliocrinus existant est limité à l'océan Indien, même si on a relevé des spécimens du Miocene au Japon, ce qui est reVilateur d'une distribution plus répandue au cours du Néogène. Un emplacement de la formation de Manchioneal du Pleéstocene inférieur dans L'est de la Jamalque a livré trois espèces d'isocrinines : le Cenocrinus asterius (Linné), le Diplocrinus maclearanus (Thomson) et le Neocrinus decorus (Thomson). Ceux-ci sont présents en association avec les bourgueticrinines Democrinus ou Monachocrinus. Ces taxons sont tous existants et ils permettent de supposer que la formation de Manchioneal aurait une profondeur minimale de sedimentation d'environ 180 m à cet endroit. Cette faunc du Pleéstocene inférieur représente l'assemblage le plus diversifé de crinoides fossiles documentés dans la région des Antilles.
[Traduit par la rédaction
A Synthesis of Coral Reef Community Structure in Hawai‘i and the Caribbean.
Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017
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