1,948 research outputs found

    An Exploratory Study of Investigating the Creative Potential of Taiwanese Children

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    The question of whether creativity should be viewed as domain-general or domain-specific, and unidimensional or multidimensional, have led to a vibrant discussion among students of creativity. Following a reviewing of the relevant literature, it was decided that the present study would focus its investigation of the creative potential of Taiwanese students on verbal and visual creative abilities. Three major findings were found: first, that the relationship between verbal and visual creativity was moderate and significant, while the relationship between ideational behavior, on the one hand, and verbal creativity and visual creativity, on the other, was weak and non-significant. Second, as illustrated by our perceptual map, it appears that verbal and visual creativity are different constructs, which might tend to support the domain-specific theory of creativity. Finally, gender did not function as a moderator between verbal and visual creativity

    Asymptotics of a discrete-time particle system near a reflecting boundary

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    We examine a discrete-time Markovian particle system on the quarter-plane introduced by M. Defosseux. The vertical boundary acts as a reflecting wall. The particle system lies in the Anisotropic Kardar-Parisi-Zhang with a wall universality class. After projecting to a single horizontal level, we take the longtime asymptotics and obtain the discrete Jacobi and symmetric Pearcey kernels. This is achieved by showing that the particle system is identical to a Markov chain arising from representations of the infinite-dimensional orthogonal group. The fixed-time marginals of this Markov chain are known to be determinantal point processes, allowing us to take the limit of the correlation kernel. We also give a simple example which shows that in the multi-level case, the particle system and the Markov chain evolve differently.Comment: 16 pages, Version 2 improves the expositio

    Nonequilibrium Reweighting on the Driven Diffusive Lattice Gas

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    The nonequilibrium reweighting technique, which was recently developed by the present authors, is used for the study of the nonequilibrium steady states. The renewed formulation of the nonequlibrium reweighting enables us to use the very efficient multi-spin coding. We apply the nonequilibrium reweighting to the driven diffusive lattice gas model. Combining with the dynamical finite-size scaling theory, we estimate the critical temperature Tc and the dynamical exponent z. We also argue that this technique has an interesting feature that enables explicit calculation of derivatives of thermodynamic quantities without resorting to numerical differences.Comment: Accepted for publication in J. Phys. A (Lett.

    Angular position of nodes in the superconducting gap of YBCO

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    The thermal conductivity of a YBCO single crystal has been studied as a function of the relative orientation of the crystal axes and a magnetic field rotating in the Cu-O planes. Measurements were carried out at several temperatures below T_c and at a fixed field of 30 kOe. A four-fold symmetry characteristic of a superconducting gap with nodes at odd multiples of 45 degrees in k-space was resolved. Experiments were performed to exclude a possible macroscopic origin for such a four-fold symmetry such as sample shape or anisotropic pinning. Our results impose an upper limit of 10% on the weight of the s-wave component of the essentially d-wave superconducting order parameter of YBCO.Comment: 10 pages, 4 figure

    Growth of GaN films on porous SiC substrate by molecular-beam epitaxy

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    Porous SiC (PSiC) substrates were used for the growth of GaN by reactive molecular-beam epitaxy with ammonia as the nitrogen source. Improved quality of GaNfilms has been demonstrated for growth on PSiC substrates, as compared to that on standard 6H–SiC substrates. Cross-sectional transmission electron microscopy and electron diffraction showed a reduction in dislocation density and a higher degree of lattice and thermal relaxation in the GaNfilmsgrown on porous substrates. The submicron GaNfilms exhibit a rocking curve linewidth of 3.3 arcmin for (0002) diffraction and 13.7 arcmin for (101̄2) diffraction. Low-temperature photoluminescence showed an excitonic transition with a full width at half maximum of 9.5 meV at 15 K, as well as high quantum efficiency, on the GaN layer grown on PSiC when the thin skin layer on porous SiC was removed before growth

    Ethyl cyanide on Titan: Spectroscopic detection and mapping using ALMA

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    We report the first spectroscopic detection of ethyl cyanide (C2_2H5_5CN) in Titan's atmosphere, obtained using spectrally and spatially resolved observations of multiple emission lines with the Atacama Large Millimeter/submillimeter array (ALMA). The presence of C2_2H5_5CN in Titan's ionosphere was previously inferred from Cassini ion mass spectrometry measurements of C2_2H5_5CNH+^+. Here we report the detection of 27 rotational lines from C2_2H5_5CN (in 19 separate emission features detected at >3σ>3\sigma confidence), in the frequency range 222-241 GHz. Simultaneous detections of multiple emission lines from HC3_3N, CH3_3CN and CH3_3CCH were also obtained. In contrast to HC3_3N, CH3_3CN and CH3_3CCH, which peak in Titan's northern (spring) hemisphere, the emission from C2_2H5_5CN is found to be concentrated in the southern (autumn) hemisphere, suggesting a distinctly different chemistry for this species, consistent with a relatively short chemical lifetime for C2_2H5_5CN. Radiative transfer models show that most of the C2_2H5_5CN is concentrated at altitudes 300-600 km, suggesting production predominantly in the mesosphere and above. Vertical column densities are found to be in the range (2-5)×1014\times10^{14} cm2^{-2}.Comment: Published in 2015, ApJL, 800, L1

    Cosmological Scaling Solutions of Multiple Tachyon Fields with Inverse Square Potentials

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    We investigate cosmological dynamics of multiple tachyon fields with inverse square potentials. A phase-space analysis of the spatially flat FRW models shows that there exists power-law cosmological scaling solutions. We study the stability of the solutions and find that the potential-kinetic-scaling solution is a global attractor. However, in the presence of a barotropic fluid the solution is an attractor only in one region of the parameter space and the tracking solution is an attractor in the other region. We briefly discuss the physical consequences of these results.Comment: 10 pages, 1 figure, LaTeX2

    Elimination Of Waste Through Value Add/Non Value Add Process Analysis To Improve Cost Productivity In Manufacturing - A Case Study

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    Value Stream Mapping (VSM) is a very comprehensive tool to that allows an organization to identify sources of waste and implements process improvements. This paper describes the adoption of VSM in a semiconductor manufacturing company to improve personnel efficiency and optimize headcount in the production lines. Based on the future state of the value stream mapping a new production process flow was implemented. Non value added activities were reduced or removed by assigning butterfly operators to perform these tasks. The new system successfully resulted in the reduction of six headcounts in the taping process. This is equivalent to a saving of approximately eighty seven thousand Malaysian ringgits per annum. This systematic approach can be similarly employed by the lean practitioners to conduct lean activities in other manufacturing sectors

    Efficacy of single and double SiNx interlayers on defect reduction in GaN overlayers grown by organometallic vapor-phase epitaxy

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    We report on the growth of and evolution of defects in GaN epilayers having single- and double-layer SiNx nanoporous insertion layers. The SiNx was formed in situ in the growth chamber of an organometallic vapor-phase epitaxy system by simultaneous flow of diluted silane and ammonia. The GaN epilayers and SiNx interlayers were grown on 6H-SiC substrates using three different nucleation layers, namely, low-temperature GaN, high-temperature GaN, and high-temperature AlN nucleation layers. X-ray-diffraction rocking curves and cross-sectional and plan-view transmission electron microscope analyses indicated that a nanoporous SiNx layer can reduce the dislocations density in the GaN overgrown layer to ∼3×108cm−2 range; below this level the defect blocking effect of SiNx would saturate. Therefore the insertion of a second SiNx layer becomes much less effective in reducing dislocations, although it continues to reduce the point defects, as suggested by time-resolved photoluminescence measurements. The insertion of SiNx interlayers was found to improve significantly the mechanical strength of the GaN epilayers resulting in a much lower crack line density

    Association of low arousal threshold obstructive sleep apnea manifestations with body fat and water distribution

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    Obstructive sleep apnea (OSA) with a low arousal threshold (low-ArTH) phenotype can cause minor respiratory events that exacerbate sleep fragmentation. Although anthropometric features may affect the risk of low-ArTH OSA, the associations and underlying mechanisms require further investigation. This study investigated the relationships of body fat and water distribution with polysomnography parameters by using data from a sleep center database. The derived data were classified as those for low-ArTH in accordance with criteria that considered oximetry and the frequency and type fraction of respiratory events and analyzed using mean comparison and regression approaches. The low-ArTH group members (n = 1850) were significantly older and had a higher visceral fat level, body fat percentage, trunk-to-limb fat ratio, and extracellular-to-intracellular (E-I) water ratio compared with the non-OSA group members (n = 368). Significant associations of body fat percentage (odds ratio [OR]: 1.58, 95% confident interval [CI]: 1.08 to 2.3, p < 0.05), trunk-to-limb fat ratio (OR: 1.22, 95% CI: 1.04 to 1.43, p < 0.05), and E-I water ratio (OR: 1.32, 95% CI: 1.08 to 1.62, p < 0.01) with the risk of low-ArTH OSA were noted after adjustments for sex, age, and body mass index. These observations suggest that increased truncal adiposity and extracellular water are associated with a higher risk of low-ArTH OSA
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