18,546 research outputs found
Inhomogeneous substructures hidden in random networks
We study the structure of the load-based spanning tree (LST) that carries the
maximum weight of the Erdos-Renyi (ER) random network. The weight of an edge is
given by the edge-betweenness centrality, the effective number of shortest
paths through the edge. We find that the LSTs present very inhomogeneous
structures in contrast to the homogeneous structures of the original networks.
Moreover, it turns out that the structure of the LST changes dramatically as
the edge density of an ER network increases, from scale free with a cutoff,
scale free, to a starlike topology. These would not be possible if the weights
are randomly distributed, which implies that topology of the shortest path is
correlated in spite of the homogeneous topology of the random network.Comment: 4 pages, 4 figure
Quantum super-cavity with atomic mirrors
We study single-photon transport in an array of coupled microcavities where
two two-level atomic systems are embedded in two separate cavities of the
array. We find that a single-photon can be totally reflected by a single
two-level system. However, two separate two-level systems can also create,
between them, single-photon quasi-bound states. Therefore, a single two-level
system in the cavity array can act as a mirror while a different type of cavity
can be formed by using two two-level systems, acting as tunable "mirrors",
inside two separate cavities in the array. In analogy with superlattices in
solid state, we call this new "cavity inside a coupled-cavity array" a
super-cavity. This supercavity is the quantum analog of Fabry-Perot
interferometers. Moreover, we show that the physical properties of this quantum
super-cavity can be adjusted by changing the frequencies of these two-level
systems.Comment: 13 pages, 9 figure
Research needs for planning and policy
노트 : Korean Agriculture Sector Study (KASS) Researcher Workshop (1973 : Seoul, KR
Kass development issues
노트 : Korean Agriculture Sector Study (KASS) Decision Maker Workshop (1973 : Seoul, KR
Low Pressure Ethenolysis of Renewable Methyl Oleate in a Microchemical System
A microchemical system for ethenolysis of renewable methyl oleate was developed, in which the dual-phase, microfluidic design enabled efficient diffusion of ethylene gas into liquid methyl oleate through an increased contact area. The increased mass transfer of ethylene favored the formation of desired commodity chemicals with significantly suppressed homometathesis when compared to the bulk system. In addition to higher selectivity and conversion, this system also provides the typical advantages of a microchemical system, including the possibility of convenient scale-up
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