7,577 research outputs found
The effect of gluon condensate on holographic heavy quark potential
The gluon condensate is very sensitive to the QCD deconfinement transition
since its value changes drastically with the deconfinement transition. We
calculate the gluon condensate dependence of the heavy quark potential in
AdS/CFT to study how the property of the heavy quarkonium is affected by a
relic of the deconfinement transition. We observe that the heavy quark
potential becomes deeper as the value of the gluon condensate decreases. We
interpret this as a dropping of the heavy quarkonium mass just above the
deconfinement transition, which is similar to the results obtained from QCD sum
rule and from a bottom-up AdS/QCD model.Comment: 16 pages, 6 figures, typos corrected, references adde
Automatic Mobile Translation System for Web Accessibility based on Smart-Phone
As mobile devices like smart phone prospers, the necessity of mobile web pages is ever increasing while the traditional web services are performed with the existing web pages. To satisfy the those requirement, this paper introduces an automatic mobile translation system that can examine the legacy web pages and produce new mobile web pages in accord to the web accessibility. For this purpose, the regulation for the web accessibility should be built first and the recommendation for a new web page would be performed based on the regulation by the system
Non-Einstein Viscosity Phenomenon of AcrylonitrileâButadieneâStyrene Composites Containing LigninâPolycaprolactone Particulates Highly Dispersed by High-Shear Stress
Lignin powder was modified via ring-opening polymerization of caprolactone to form a ligninâpolycaprolactone (LPCL) particulate. The LPCL particulates were mixed with an acrylonitrileâbutadieneâstyrene (ABS) matrix at an extremely high rotational speed of up to 3000 rpm, which was achieved by a closed-loop screw mixer and in-line melt extruder. Using this high-shear extruding mixer, the LPCL particulate size was controlled in the range of 3395 nm (conventional twin-screw extrusion) down to 638 nm (high-shear mixer of 3000 rpm) by altering the mixing speed and time. The resulting LPCL/ABS composites clearly showed non-Einstein viscosity phenomena, exhibiting reduced viscosity (2130 Pa·s) compared to the general extruded composite one (4270 Pa·s) at 1 sâ1 and 210 °C. This is due to the conformational rearrangement and the increased free volume of ABS molecular chains in the vicinity of LPCL particulates. This was supported by the decreased glass transition temperature (Tg, 83.7 °C) of the LPCL/ABS composite specimens, for example, giving a 21.8% decrement compared to that (107 °C) of the neat ABS by the incorporation of 10 wt % LPCL particulates in ABS. The LPCL particulate morphology, damping characteristics, and light transmittance of the developed composites were thoroughly investigated at various levels of applied shear rates and mixing conditions. The non-Einstein rheological phenomena stemming from the incorporation of LPCL particulates suggest an interesting plasticization methodology: to improve the processability of high-loading filler/polymer composites and ultra-high molecular weight polymers that are difficult to process because of their high viscosity
Generalized gravity model for human migration
The gravity model (GM) analogous to Newton's law of universal gravitation has
successfully described the flow between different spatial regions, such as
human migration, traffic flows, international economic trades, etc. This simple
but powerful approach relies only on the 'mass' factor represented by the scale
of the regions and the 'geometrical' factor represented by the geographical
distance. However, when the population has a subpopulation structure
distinguished by different attributes, the estimation of the flow solely from
the coarse-grained geographical factors in the GM causes the loss of
differential geographical information for each attribute. To exploit the full
information contained in the geographical information of subpopulation
structure, we generalize the GM for population flow by explicitly harnessing
the subpopulation properties characterized by both attributes and geography. As
a concrete example, we examine the marriage patterns between the bride and the
groom clans of Korea in the past. By exploiting more refined geographical and
clan information, our generalized GM properly describes the real data, a part
of which could not be explained by the conventional GM. Therefore, we would
like to emphasize the necessity of using our generalized version of the GM,
when the information on such nongeographical subpopulation structures is
available.Comment: 14 pages, 6 figures, 2 table
Theory of magnetic field-induced metaelectric critical end point in BiMnO
A recent experiment on the multiferroic BiMnO compound under a strong
applied magnetic field revealed a rich phase diagram driven by the coupling of
magnetic and charge (dipolar) degrees of freedom. Based on the
exchange-striction mechanism, we propose here a theoretical model with the
intent to capture the interplay of the spin and dipolar moments in the presence
of a magnetic field in BiMnO. Experimentally observed behavior of the
dielectric constants, magnetic susceptibility, and the polarization is, for the
most part, reproduced by our model. The critical behavior observed near the
polarization reversal point in the phase diagram is interpreted as
arising from the proximity to the critical end point.Comment: Theory; relevant experiment uploaded as arXiv:0810.190
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