31,201 research outputs found
X(3915) and X(4350) as new members in P-wave charmonium family
The analysis of the mass spectrum and the calculation of the strong decay of
P-wave charmonium states strongly support to explain the newly observed X(3915)
and X(4350) as new members in P-wave charmonium family, i.e.,
for X(3915) and for X(4350).
Under the P-wave charmonium assignment to X(3915) and X(4350), the
quantum numbers of X(3915) and X(4350) must be and
respectively, which provide the important criterion to test P-wave charmonium
explanation for X(3915) and X(4350) proposed by this letter. The decay behavior
of the remaining two P-wave charmonium states with the second radial excitation
is predicted, and experimental search for them is suggested.Comment: 4 pages, 2 figures, 2 tables. More references and discussions added,
typos corrected. Accepted for publication in Phys. Rev. Lett
Community Detection from Location-Tagged Networks
Many real world systems or web services can be represented as a network such
as social networks and transportation networks. In the past decade, many
algorithms have been developed to detect the communities in a network using
connections between nodes. However in many real world networks, the locations
of nodes have great influence on the community structure. For example, in a
social network, more connections are established between geographically
proximate users. The impact of locations on community has not been fully
investigated by the research literature. In this paper, we propose a community
detection method which takes locations of nodes into consideration. The goal is
to detect communities with both geographic proximity and network closeness. We
analyze the distribution of the distances between connected and unconnected
nodes to measure the influence of location on the network structure on two real
location-tagged social networks. We propose a method to determine if a
location-based community detection method is suitable for a given network. We
propose a new community detection algorithm that pushes the location
information into the community detection. We test our proposed method on both
synthetic data and real world network datasets. The results show that the
communities detected by our method distribute in a smaller area compared with
the traditional methods and have the similar or higher tightness on network
connections
Microstructural Characterization of Shrouded Plasma-Sprayed Titanium Coatings
Titanium and its alloys are often used for corrosion protection because they are able to
offer high chemical resistance against various corrosive media. In this paper, shrouded plasma spray
technology was applied to produce titanium coatings. A solid shroud with an external shrouding
gas was used to plasma spray titanium powder feedstock with aim of reducing the oxide content
in the as-sprayed coatings. The titanium coatings were assessed by optical microscope, scanning
electron microscopy, X-ray diffraction, LECO combustion method and Vickers microhardness testing.
The results showed that the presence of the shroud and the external shrouding gas led to a dense
microstructure with a low porosity in the plasma-sprayed titanium coatings. The oxygen and nitrogen
contents in the titanium coating were kept at a low level due to the shielding effect of the shroud
attachment and the external shrouding gas. The dominant phase in the shrouded titanium coatings
was mainly composed of α-Ti phase, which was very similar to the titanium feedstock powders.
The shrouded plasma-sprayed titanium coatings had a Vickers microhardness of 404.2 ± 103.2 HV
Genetic incorporation of D-Lysine into diketoreductase in Escherichia coli cells
D-Lysine has been genetically introduced into diketoreductase in E. coli cells by utilization of an orthogonal Ph tRNA /Lysyl-tRNA synthetase pair. This is the first report on the genetic incoporation of D-amino acids into proteins, which may be generally applicable to a wide variety of applications
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