17,454 research outputs found
Thermal activation energy of 3D vortex matter in NaFe1-xCoxAs (x=0.01, 0.03 and 0.07) single crystals
We report on the thermally activated flux flow dependency on the doping
dependent mixed state in NaFe1-xCoxAs (x=0.01, 0.03, and 0.07) crystals using
the magnetoresistivity in the case of B//c-axis and B//ab-plane. It was found
clearly that irrespective of the doping ratio, magnetoresistivity showed a
distinct tail just above the Tc, offset associated with the thermally activated
flux flow (TAFF) in our crystals. Furthermore, in TAFF region the temperature
dependence of the activation energy follows the relation U(T, B)=U_0 (B)
(1-T/T_c )^q with q=1.5 in all studied crystals. The magnetic field dependence
of the activation energy follows a power law of U_0 (B)~B^(-{\alpha}) where the
exponent {\alpha} is changed from a low value to a high value at a crossover
field of B=~2T, indicating the transition from collective to plastic pinning in
the crystals. Finally, it is suggested that the 3D vortex phase is the dominant
phase in the low-temperature region as compared to the TAFF region in our
series samples
The Dropping of In-Medium Hadron Mass in Holographic QCD
We study the baryon density dependence of the vector meson spectrum using the
D4/D6 system together with the compact D4 baryon vertex. We find that the
vector meson mass decreases almost linearly in density at low density for small
quark mass, but saturates to a finite non-zero value for large density. We also
compute the density dependence of the mass and the
velocity. We find that in medium, our model is consistent with the GMOR
relation up to a few times the normal nuclear density. We compare our hQCD
predictions with predictions made based on hidden local gauge theory that is
constructed to model QCD.Comment: 20 pages, 7 figure
The Estimation of Minimum Efficient Scale of the Port Industry
publisher: Elsevier articletitle: The estimation of minimum efficient scale of the port industry journaltitle: Transport Policy articlelink: http://dx.doi.org/10.1016/j.tranpol.2016.04.012 content_type: article copyright: © 2016 Elsevier Ltd. All rights reserved
The impact of seaports on the regional economies in South Korea: Panel evidence from the augmented Solow model
Inverted polymer fullerene solar cells exceeding 10% efficiency with poly(2-ethyl-2-oxazoline) nanodots on electron-collecting buffer layers
Polymer solar cells have been spotlighted due to their potential for low-cost manufacturing but their efficiency is still less than required for commercial application as lightweight/flexible modules. Forming a dipole layer at the electron-collecting interface has been suggested as one of the more attractive approaches for efficiency enhancement. However, only a few dipole layer material types have been reported so far, including only one non-ionic (charge neutral) polymer. Here we show that a further neutral polymer, namely poly(2-ethyl-2-oxazoline) (PEOz) can be successfully used as a dipole layer. Inclusion of a PEOz layer, in particular with a nanodot morphology, increases the effective work function at the electron-collecting interface within inverted solar cells and thermal annealing of PEOz layer leads to a state-of-the-art 10.74% efficiency for single-stack bulk heterojunction blend structures comprising poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-alt-3-fluorothieno[3,4-b]thiophene-2-carboxylate] as donor and [6,6]-phenyl-C71-butyric acid methyl ester as acceptor
The impact of innovativeness on supply chain performance: is supply chain integration a missing link?
© Emerald Group Publishing Limited. Purpose - This purpose of this paper is to study the impact of innovativeness on supply chain integration (SCI) and supply chain performance (SCP) and the role of SCI in mediating between innovativeness in the supply chain and SCP. Innovativeness is an accepted driver to leverage firm performance. SCI and SCP require innovativeness in the supply chain, but their interrelationships have rarely been researched empirically.P Design/methodology/approach - A questionnaire survey and structural equation modelling were used in this work. After a structural and measurement model was devised from existing supply chain literature, the main data were collected in a web-based questionnaire survey of South Korean manufacturers. Structural equation modelling was applied to test proposed hypotheses on the associations between variables, following a hierarchical analysis process.P Findings - Innovativeness in the supply chain had a positive impact on both SCI and SCP. However, the direct impact of innovativeness on SCP disappeared when the model included SCI as a mediator. In specific, internal and supplier integration fully mediated innovativeness-SCP relationships, whereas customer integration had no mediating role on those relationships. The findings suggest that innovativeness can influence SCP only when the manufacturer’s level of SCI is sufficiently effective in developing necessary supply chain practices.P Research limitations/implications - In this work, innovativeness in the supply chain effectively influenced SCP through the mediation of SCI. However, cross-sectional analysis in one nation using one response per organisation invites validation embracing other geographical areas and longitudinal studies.P Practical implications - Design of an innovative culture within a firm and along a supply chain can enhance SCI practices by stimulating innovativeness. A high level of SCI should be pursued to effectively transform innovativeness into performance.P Originality/value - This work seminally examines the effect of innovativeness in the supply chain on SCI and SCP as well as the mediating role of SCI in the relationships between innovativeness and SCP
Acute Response of Different High - intensity Interval Training Protocols on Cardiac Auto - regulation.
poste
20 K superconductivity in heavily electron doped surface layer of FeSe bulk crystal
A superconducting transition temperature Tc as high as 100 K was recently
discovered in 1 monolayer (1ML) FeSe grown on SrTiO3 (STO). The discovery
immediately ignited efforts to identify the mechanism for the dramatically
enhanced Tc from its bulk value of 7 K. Currently, there are two main views on
the origin of the enhanced Tc; in the first view, the enhancement comes from an
interfacial effect while in the other it is from excess electrons with strong
correlation strength. The issue is controversial and there are evidences that
support each view. Finding the origin of the Tc enhancement could be the key to
achieving even higher Tc and to identifying the microscopic mechanism for the
superconductivity in iron-based materials. Here, we report the observation of
20 K superconductivity in the electron doped surface layer of FeSe. The
electronic state of the surface layer possesses all the key spectroscopic
aspects of the 1ML FeSe on STO. Without any interface effect, the surface layer
state is found to have a moderate Tc of 20 K with a smaller gap opening of 4
meV. Our results clearly show that excess electrons with strong correlation
strength alone cannot induce the maximum Tc, which in turn strongly suggests
need for an interfacial effect to reach the enhanced Tc found in 1ML FeSe/STO.Comment: 5 pages, 4 figure
Extensive spatiotemporal analyses of surface ozone and related meteorological variables in South Korea for the period 1999–2010
Spatiotemporal characteristics of surface ozone (O<sub>3</sub>) variations over
South Korea are investigated with consideration of meteorological factors
and timescales based on the Kolmogorov–Zurbenko filter (KZ filter), using
measurement data at 124 air quality monitoring sites and 72 weather stations
for the 12 yr period of 1999–2010. In general, O<sub>3</sub> levels at coastal
cities are high due to dynamic effects of the sea breeze while those at the
inland and Seoul Metropolitan Area (SMA) cities are low due to the NO<sub>x</sub>
titration by local precursor emissions. We examine the meteorological
influences on O<sub>3</sub> using a combined analysis of the KZ filter and linear
regressions between O<sub>3</sub> and meteorological variables. We decomposed
O<sub>3</sub> time series at each site into short-term, seasonal, and long-term
components by the KZ filter and regressed on meteorological variables.
Impact of temperature on the O<sub>3</sub> levels is significantly high in the
highly populated SMA and inland region, but low in the coastal region. In
particular, the probability of high O<sub>3</sub> occurrence doubles with
4 °C of temperature increase in the SMA during high O<sub>3</sub> months
(May–October). This implies that those regions will experience frequent
high O<sub>3</sub> events in a future warming climate. In terms of short-term
variation, the distribution of high O<sub>3</sub> probability classified by wind
direction shows the effect of both local precursor emissions and long-range
transport from China. In terms of long-term variation, the O<sub>3</sub>
concentrations have increased by +0.26 ppbv yr<sup>−1</sup> (parts per billion by volume) on nationwide
average, but their trends show large spatial variability. Singular value
decomposition analyses further reveal that the long-term temporal evolution
of O<sub>3</sub> is similar to that of nitrogen dioxide, although the spatial
distribution of their trends is different. This study will be helpful as a
reference for diagnostics and evaluation of regional- and local-scale
O<sub>3</sub> and climate simulations, and as a guide to appropriate O<sub>3</sub>
control policy in South Korea
- …