2,618 research outputs found

    준금속의 위상학적 초전도성

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    학위논문(박사) - 한국과학기술원 : 물리학과, 2020.8,[vii, 67 p. :]In this dissertation, we investigate topological superconducting states in semimetals. Unlike many of previous literatures which focused on Dirac/Weyl semimetals, we investigated physical properties of spin-orbit coupled multi-band systems where the electrons with higher-pseudospin can be realized near the Fermi level. We found new kind of topological superconducting phases which have gapless Bogoliubov quasiparticles and furthermore have topological invariants for each nodal line or Bogoliubov Fermi surface. Adopting the Ginzburg–Landau theory, we also investigate the stability of each phase within one-loop calculations.한국과학기술원 :물리학과

    Efficient Jacobian-Based Inverse Kinematics With Sim-to-Real Transfer of Soft Robots by Learning

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    This article presents an efficient learning-based method to solve the <italic>inverse kinematic</italic> (IK) problem on soft robots with highly nonlinear deformation. The major challenge of efficiently computing IK for such robots is due to the lack of analytical formulation for either forward or inverse kinematics. To address this challenge, we employ neural networks to learn both the mapping function of forward kinematics and also the Jacobian of this function. As a result, Jacobian-based iteration can be applied to solve the IK problem. A sim-to-real training transfer strategy is conducted to make this approach more practical. We first generate a large number of samples in a simulation environment for learning both the kinematic and the Jacobian networks of a soft robot design. Thereafter, a sim-to-real layer of differentiable neurons is employed to map the results of simulation to the physical hardware, where this sim-to-real layer can be learned from a very limited number of training samples generated on the hardware.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and ManufacturingMechatronic Desig

    Pair Density Waves and Supercurrent Diode Effect in Altermagnets

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    Metallic altermagnets are unusual collinear magnets that feature zero net magnetization with momentum-dependent spin splitting. Here, we show that this spin splitting can induce pair density wave states even in the absence of external magnetic fields. Focusing on BCS-type attractive interactions, we find the stabilization of symmetrically distinct pair density wave states depending on the chemical potential. These states include Fulde-Ferrell and Fulde-Ferrell* states, both of which break inversion symmetry. We investigate the supercurrent properties and discover non-reciprocal supercurrents for both the Fulde-Ferrell and Fulde-Ferrell* states with distinct spatial dependencies. We propose that the supercurrent diode effect can serve as an experimental tool for distinguishing between different pair density waves in metallic altermagnets and discuss the relation to material candidates.Comment: 9 pages, 5 figure

    Alpha particle spectroscopy using FNTD and SIM super-resolution microscopy

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    Structured illumination microscopy (SIM) for the imaging of alpha particle tracks in fluorescent nuclear track detectors (FNTD) was evaluated and compared to confocal laser scanning microscopy (CLSM). FNTDs were irradiated with an external alpha source and imaged using both methodologies. SIM imaging resulted in improved resolution, without increase in scan time. Alpha particle energy estimation based on the track length, direction and intensity produced results in good agreement with the expected alpha particle energy distribution. A pronounced difference was seen in the spatial scattering of alpha particles in the detectors, where SIM showed an almost 50% reduction compared to CLSM. The improved resolution of SIM allows for more detailed studies of the tracks induced by ionising particles. The combination of SIM and FNTDs for alpha radiation paves the way for affordable and fast alpha spectroscopy and dosimetry. Journal compilatio

    A simple disc wind model for broad absorption line quasars

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    Approximately 20 per cent of quasi-stellar objects (QSOs) exhibit broad, blue-shifted absorption lines in their ultraviolet spectra. Such features provide clear evidence for significant outflows from these systems, most likely in the form of accretion disc winds. These winds may represent the ‘quasar’ mode of feedback that is often invoked in galaxy formation/evolution models, and they are also key to unification scenarios for active galactic nuclei (AGN) and QSOs. To test these ideas, we construct a simple benchmark model of an equatorial, biconical accretion disc wind in a QSO and use a Monte Carlo ionization/radiative transfer code to calculate the ultraviolet spectra as a function of viewing angle. We find that for plausible outflow parameters, sightlines looking directly into the wind cone do produce broad, blue-shifted absorption features in the transitions typically seen in broad absorption line (BAL) QSOs. However, our benchmark model is intrinsically X-ray weak in order to prevent overionization of the outflow, and the wind does not yet produce collisionally excited line emission at the level observed in non-BAL QSOs. As a first step towards addressing these shortcomings, we discuss the sensitivity of our results to changes in the assumed X-ray luminosity and mass-loss rate, Ṁwind. In the context of our adopted geometry, Ṁwind ∼ Ṁacc is required in order to produce significant BAL features. The kinetic luminosity and momentum carried by such outflows would be sufficient to provide significant feedback

    Connecticut State Innovation Model (SIM); Proposed framework--revised 4/30/19

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    1 online resource (32 pages) : color illustrationsFinal version; "This report was prepared by Health Management Associates (HMA), a leading independent national research and consulting firm"--Page 3; "The project described was supported by Funding Opportunity Number CMS-1G1CMS331630-02-00 from the U.S. Department of Health & Human Services, Centers for Medicare & Medicaid Services."; "Approved June 2019."; Includes bibliographical reference

    Old Brisbane Botanic Gardens: Conservation Plan Review 2005, Report of Stage 1 Heritage Significance and Conservation Policies

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    Report for City Design, for Environment and Parks, within the Brisbane City Council.\ud \ud Context of this Project\ud \ud A Conservation Study for the Old Brisbane Botanic Gardens,\ud formerly called the Brisbane City Botanic Gardens, was finalised in\ud 1995 and prepared by Jeannie Sim for the Landscape Section of\ud Brisbane City Council, the same author of the present report. This\ud unpublished report was the first conservation plan prepared for the\ud place and it was recommended that it be reviewed in five years\ud time. That time has arrived finally with the preparation of the 2005\ud Review. The present project was commissioned by City Design on\ud behalf of Environment and Parks Section of Brisbane City Council.\ud \ud The author has purposely chosen to call the study site the 'Old\ud Brisbane Botanic Gardens' (OBBG) to differentiate it from the\ud Brisbane Botanic Gardens, Mt. Coot-tha (BBG-MC), and to\ud maintain the claim for this original garden to remain as a botanic\ud garden for Brisbane. This name immediately brings to mind an\ud association with history, as in the precedent set by the naming of\ud the nearby 'Old Government House' at Gardens Point

    Post-disaster school relocation : a case study of Chinese students’ adjustment after the Wenchuan earthquake

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    Author name used in this publication: Ng, Guat Tin.Author name used in this publication: Sim, Timothy.Accepted ManuscriptPublishedGreen (AAM
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