The Group Learning At Significant Scale (GLASS) approach is developed to increase the scalability and efficacy of student design teams during group sessions of a Flipped Classroom (FC), as well as conventional modalit...
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The Group Learning At Significant Scale (GLASS) approach is developed to increase the scalability and efficacy of student design teams during group sessions of a Flipped Classroom (FC), as well as conventional modality courses. GLASS utilizes freely-available collaboration tools to facilitate instructional delivery, assessment, and review of teams that leverage campus WiFi connectivity, along with a pedagogical approach using excerpts from actual data sheets and open Internet resources. This immersive collaborative design experience is interwoven on a weekly basis with the technical content provided via video during the preceding week. The instructor manages multiple design teams to conduct a weekly Challenge Problem during inclass time. First, students are randomized by the Learning Management System into small groups. Second, a challenge problem is provided, delivered via WiFi-enabled laptops, tablets, or smart phones, forming virtual design teams, regardless of where students are seated. Third, students utilize their WiFi enabled devices to discuss the challenge question via chatroom-style dialog channels alongside a solution whiteboard and/or figure drawing space, while utilizing open resources on the Internet to postulate a solution. Fourth, once the design team concurs that their results are complete, they submit their answers to the Learning Management System (LMS) for auto-grading and score-recording in the grade book. Credit is earned by correctly answering each designated question sub-part, which provides partial credit. Throughout the team design activity, the instructor monitors the assignment progress online in real-time, including windows for each design team showing a solution draft as it is constructed, and providing feedback via each group's designated chat channel. LMS statistics are available in real-time for the autograded answer of the first design team having a correct solution, dubbed the Pioneer Group, which receives a bonus after its group l
We propose a paradigm for the realization of nonreciprocal photonic devices based on time-modulated graphene capacitors coupled to photonic waveguides, without relying on magneto-optic effects. The resulting hybrid gr...
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We propose a paradigm for the realization of nonreciprocal photonic devices based on time-modulated graphene capacitors coupled to photonic waveguides, without relying on magneto-optic effects. The resulting hybrid graphene-dielectric platform is low loss, silicon compatible, robust against graphene imperfections, scalable from terahertz to near-infrared frequencies, and it exhibits large nonreciprocal responses using realistic biasing schemes. We introduce an analytical framework based on solving the eigenstates of the modulated structure and on spatial coupled mode theory, unveiling the physical mechanisms that enable nonreciprocity and enabling a quick analysis and design of optimal isolator geometries based on synthetic linear and angular momentum bias. Our results, validated through harmonic-balance full-wave simulations, confirm the feasibility of the introduced low-loss (<3 dB) platform to realize large photonic isolation through various mechanisms, such as narrow-band asymmetric band gaps and interband photonic transitions that allow multiple isolation frequencies and large bandwidths. We envision that this technology may pave the wave to magnetic-free, fully integrated, and CMOS–compatible nonreciprocal components with wide applications in photonic networks and thermal management.
作者：
Bobb, KamauProgram Officer
National Science Foundation Directorate of Computer and Information Science and Engineering 4201 Wilson Boulevard ArlingtonVA22230 United States
For many important network types (e.g., sensor networks in complex harsh environments and social networks) physical coordinate systems (e.g., Cartesian), and physical distances (e.g., Euclidean), are either difficult ...
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Having both avian-like receptors (?±2,3-linked sialic acid, SA2,3Gal) and human-like receptors (?±2,6-linked sialic acid, SA2,6Gal), swine are proposed as??úmixing vessel??ùfor generating influenza...
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Having both avian-like receptors (?±2,3-linked sialic acid, SA2,3Gal) and human-like receptors (?±2,6-linked sialic acid, SA2,6Gal), swine are proposed as??úmixing vessel??ùfor generating influenza pandemic strains. Laboratory experiments suggested all HA subtypes of influenza A virus (IAV) can infect swine. However, only sporadic cases of avian
We report the magnetic response of Pt/Au/GdFeCo trilayers to optical irradiation of the Pt surface. For trilayers with Au thickness greater than 50 nm, the great majority of energy is absorbed by the Pt layer, creatin...
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We report the magnetic response of Pt/Au/GdFeCo trilayers to optical irradiation of the Pt surface. For trilayers with Au thickness greater than 50 nm, the great majority of energy is absorbed by the Pt layer, creating an initial temperature differential of thousands of kelvin between the Pt/Au layers and the GdFeCo layer. The resulting electronic heat current across the metal multilayer lasts for several picoseconds with energy flux in excess of 2TWm−2 and provides sufficient heating to the GdFeCo electrons to induce deterministic reversal of the magnetic moment.
The human visual system employs a mechanism of visual attention, which selects only part of the incoming information for further processing. Through this mechanism, the brain avoids overloading its limited cognitive c...
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We report the magnetic response of Co/Pt multilayers to picosecond electrical heating. Using photoconductive Auston switches, we generate electrical pulses with 5.5 ps duration and hundreds of pico-Joules to pass thro...
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We report the magnetic response of Co/Pt multilayers to picosecond electrical heating. Using photoconductive Auston switches, we generate electrical pulses with 5.5 ps duration and hundreds of pico-Joules to pass through Co/Pt multilayers. The electrical pulse heats the electrons in the Co/Pt multilayers and causes an ultrafast reduction in the magnetic moment. A comparison between optical and electrically induced demagnetization of the Co/Pt multilayers reveals significantly different dynamics for optical vs electrical heating. We attribute the disparate dynamics to the dependence of the electron-phonon interaction on the average energy and the total number of initially excited electrons.
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