33,207 research outputs found

    Evidence of Skyrmion excitations about ν=1\nu =1 in n-Modulation Doped Single Quantum Wells by Inter-band Optical Transmission

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    We observe a dramatic reduction in the degree of spin-polarization of a two-dimensional electron gas in a magnetic field when the Fermi energy moves off the mid-point of the spin-gap of the lowest Landau level, ν=1\nu=1. This rapid decay of spin alignment to an unpolarized state occurs over small changes to both higher and lower magnetic field. The degree of electron spin polarization as a function of ν\nu is measured through the magneto-absorption spectra which distinguish the occupancy of the two electron spin states. The data provide experimental evidence for the presence of Skyrmion excitations where exchange energy dominates Zeeman energy in the integer quantum Hall regime at ν=1\nu=1

    A Hands-On, Active Learning Approach to Increasing Manufacturing Knowledge in Engineering Students

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    This paper describes a new learning module implemented as part of the senior capstone design course at Marquette University to teach engineering students about basic manufacturing processes, lean manufacturing principles, and design for manufacturability. The module includes several examples of active and student centered learning as part of an in-class assembly line simulation exercise. Students reflected on this experience, and suggested process improvements to save time, reduce cost and waste, and improve the assembly line process. They learned of the importance of manufacturing documentation, process design, and design for assembly. At the end of the module, students understood the importance of designing a product not only for the end user, but also for the assemblers and inspectors. Details of the module design and implementation will be presented along with comments from students

    Dielectric cure monitoring: Preliminary studies

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    Preliminary studies have been conducted on two types of dielectric cure monitoring systems employing both epoxy resins and phenolic composites. An Audrey System was used for 23 cure monitoring runs with very limited success. Nine complete cure monitoring runs have been investigated using a Micromet System. Two additional measurements were performed to investigate the Micromet's sensitivity to water absorption in a post-cure carbon-phenolic material. While further work is needed to determine data significance, the Micromet system appears to show promise as a feedback control device during processing

    A modeling analysis program for the JPL table mountain Io sodium cloud

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    A data quality review for the entire set of the 1981 Region B/C images has been completed and is presented. The review indicates that almost all images are of sufficient quality to be valuable in our analysis of this data set. Five data-correlation studies for the same data set have also been completed and are useful in classifying and studying the sodium cloud morphology and its interactions with solar radiation pressure and the plasma torus. Additional progress in developing new image processing techniques and in improving the Io sodium cloud model is also discussed

    Foreign and domestic bank participation in emerging markets: lessons from Mexico and Argentina

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    It is generally agreed that strong domestic financial systems play an important role in attaining overall economic development and stabilization. The role played by foreign banks in achieving this goal, however, is still controversial. This article brings new evidence to the debate over foreign participation by examining the lending patterns of domestic and foreign banks in Argentina and Mexico during the 1990s. The authors conclude that foreign banks in both countries typically have stronger and less volatile loan growth than their domestic counterparts. The corollary to this finding, however, is that bank health—not ownership per se—is the critical element in the growth, volatility, and cyclicality of bank credit. Still, diversity of ownership is found to contribute to greater credit stability in times of financial system turmoil and weakness.Bank loans - Argentina ; Bank loans - Mexico ; Banks and banking, Foreign ; Argentina ; Mexico

    Using giant scarlet runner bean embryos to uncover regulatory networks controlling suspensor gene activity.

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    One of the major unsolved issues in plant development is understanding the regulatory networks that control the differential gene activity that is required for the specification and development of the two major embryonic regions, the embryo proper and suspensor. Historically, the giant embryo of scarlet runner bean (SRB), Phaseolus coccineus, has been used as a model system to investigate the physiological events that occur early in embryogenesis-focusing on the question of what role the suspensor region plays. A major feature distinguishing SRB embryos from those of other plants is a highly enlarged suspensor containing at least 200 cells that synthesize growth regulators required for subsequent embryonic development. Recent studies have exploited the giant size of the SRB embryo to micro-dissect the embryo proper and suspensor regions in order to use genomics-based approaches to identify regulatory genes that may be involved in controlling suspensor and embryo proper differentiation, as well as the cellular processes that may be unique to each embryonic region. Here we review the current genomics resources that make SRB embryos a compelling model system for studying the early events required to program embryo development

    An Anderson-Fano Resonance and Shake-Up Processes in the Magneto-Photoluminescence of a Two-Dimensional Electron System

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    We report an anomalous doublet structure and low-energy satellite in the magneto-photoluminescence spectra of a two-dimensional electron system. The doublet structure moves to higher energy with increasing magnetic field and is most prominent at odd filling factors 5 and 3. The lower-energy satellite peak tunes to lower energy for increasing magnetic field between filling factor 6 and 2. These features occur at energies below the fundamental band of recombination originating from the lowest Landau level and display striking magnetic field and temperature dependence that indicates a many-body origin. Drawing on a recent theoretical description of Hawrylak and Potemski, we show that distinct mechanisms are responsible for each feature.Comment: 14 pages including 5 figures. To appear in the April 15th edition of Phy. Rev. B. rapid com
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