6,006 research outputs found

    A study on the turbulent transport of an advective nature in the fluid plasma

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    Advective nature of the electrostatic turbulent flux of plasma energy is studied numerically in a nearly adiabatic state. Such a state is represented by the Hasegawa-Mima equation that is driven by a noise that may model the destabilization due to the phase mismatch of the plasma density and the electric potential. The noise is assumed to be Gaussian and not to be invariant under reflection along a direction s^\hat s. It is found that the flux density induced by such noise is anisotropic: While it is random along s^\hat s, it is not along the perpendicular direction s^{\hat s}_\perp and the flux is not diffusive. The renormalized response may be approximated as advective with the velocity being proportional to (kρs)2(k\rho_s)^2 in the Fourier space k\vec k

    Correlated Electronic Structures and the Phase Diagram of Hydrocarbon-based Superconductors

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    We have investigated correlated electronic structures and the phase diagram of electron-doped hydrocarbon molecular solids, based on the dynamical mean-field theory. We have found that the ground state of hydrocarbon-based superconductors such as electron-doped picene and coronene is a multi-band Fermi liquid, while that of non-superconducting electron-doped pentacene is a single-band Fermi liquid in the proximity of the metal-insulator transition. The size of the molecular orbital energy level splitting plays a key role in producing the superconductivity of electron-doped hydrocarbon solids. The multi-band nature of hydrocarbon solids would boost the superconductivity through the enhanced density of states at the Fermi level.X11910sciescopu

    Topological Structure of Dense Hadronic Matter

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    We present a summary of work done on dense hadronic matter, based on the Skyrme model, which provides a unified approach to high density, valid in the large NcN_c limit. In our picture, dense hadronic matter is described by the {\em classical} soliton configuration with minimum energy for the given baryon number density. By incorporating the meson fluctuations on such ground state we obtain an effective Lagrangian for meson dynamics in a dense medium. Our starting point has been the Skyrme model defined in terms of pions, thereafter we have extended and improved the model by incorporating other degrees of freedom such as dilaton, kaons and vector mesons.Comment: 13 pages, 8 figures, Talk given at the KIAS-APCTP Symposium in Astro-Hadron Physics "Compact Stars: Quest for New States of Dense Matter", November 10-14, 2003, Seoul, Korea, published by World Scientific. Based on talk by B.-Y. Par

    Experimental Study on Effects of Lubricant Oil in a Domestic Refrigerator-Freezer

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    Lubricant oil is essential for lubricating moving parts and cooling the components in a refrigerant compressor. However, the oil deteriorates heat transfer performance in the heat exchangers, and increases pressure drop in a refrigeration circuit. In this study, investigation of the effects of lubricant oil circulating in heat exchangers on the performance of the domestic refrigerator-freezer was carried out by performing some experiments. The experiments were conducted for conventional and oil-less systems with using a linear compressor in an environmental chamber to compare the cooling capacity, power consumption, and operating characteristics such as temperatures and pressures at inlets and outlets of each component, mass flow rate, and cooling time. The cooling capacity and power consumption of two systems were measured during the on-off cyclic tests. Comparing the experimental data for the conventional and the oil-less systems, the discharge temperature of the oil-less system is higher than that of the conventional system more than 20℃. However, due to the oil removal, the heat transfer performance was improved and the condenser outlet temperature was measured lower than the conventional about 1℃. The power consumption of the oil-less system was reduced by about 4.0% compared to the system with the lubricant oil

    The Effect of Ad Exposure on Consumer Visual Attentions Depending on Time Lapse in the Context of eSports

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    PURPOSE This study examined how consumers' visual attention to ads during eSports media consumption varies over time. METHODS An experimental study with a single factor, three-level within subject experimental design was conducted, utilizing an eye-tracker to measure visual attentions, including fixation count and duration. Seventy-eight students from a national university in city B participated in the experiment. A repeated measures ANOVA was conducted using the open-source statistical program R to test the research hypothesis. RESULTS Both the fixation count and duration were highest for the first ad and then gradually decreased for the second and third ad. CONCLUSIONS It is recommended that eSports sponsors should consider differentiating ad pricing based on the order of exposure, then expose the first ad presented more frequently and for extended periods, and consider different shapes, colors, and movements to prevent adaptation to the initial allocation of attention

    Temperature-dependent evolutions of excitonic superfluid plasma frequency in a srong excitonic insulator candidate, Ta2_2NiSe5_5

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    We investigate an interesting anisotropic van der Waals material, Ta2_{2}NiSe5_{5}, using optical spectroscopy. Ta2_{2}NiSe5_{5} has been known as one of the few excitonic insulators proposed over 50 years ago. Ta2_{2}NiSe5_{5} has quasi-one dimensional chains along the aa-axis. We have obtained anisotropic optical properties of a single crystal Ta2_{2}NiSe5_{5} along the aa- and cc-axes. The measured aa- and cc-axis optical conductivities exhibit large anisotropic electronic and phononic properties. With regard to the aa-axis optical conductivity, a sharp peak near 3050 cm1^{-1} at 9 K, with a well-defined optical gap (ΔEI\Delta^{EI} \simeq 1800 cm1^{-1}) and a strong temperature-dependence, is observed. With an increase in temperature, this peak broadens and the optical energy gap closes around \sim325 K(TcEIT_c^{EI}). The spectral weight redistribution with respect to the frequency and temperature indicates that the normalized optical energy gap (ΔEI(T)/ΔEI(0)\Delta^{EI}(T)/\Delta^{EI}(0)) is 1(T/TcEI)21-(T/T_c^{EI})^2. The temperature-dependent superfluid plasma frequency of the excitonic condensation in Ta2_{2}NiSe5_{5} has been determined from measured optical data. Our findings may be useful for future research on excitonic insulators.Comment: 17 pages, 5 figure
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