44,140 research outputs found
Authentication of Chinese crude drug, Gecko, by allele-specific diagnostic PCR
Based on the sequences of the mitochondrial 12S rRNA gene fragment of 17 samples from Gekkonidae, Salamandridae, Agamidae and Hynobiidae, respectively, a pair of allele-specific primers was designed for differentiating the Chinese medicinal material Gecko from its adulterants by PCR. The results of amplification with the primers indicate that amplicons from the templates of Gekko gecko were clearly revealed by agarose gel electrophoresis, whereas no evident amplicons were found from other species. The primers were employed to identify crude drug samples from different sources, Among a total of 9 samples, 3 were diagnosed as genuine Gecko. This result is consistent with morphological identification and DNA sequence analyses
-to-Glueball form factor and Glueball production in decays
We investigate transition form factors of meson decays into a scalar
glueball in the light-cone formalism. Compared with form factors of to
ordinary scalar mesons, the -to-glueball form factors have the same power in
the expansion of . Taking into account the leading twist light-cone
distribution amplitude, we find that they are numerically smaller than those
form factors of to ordinary scalar mesons. Semileptonic ,
and decays are subsequently investigated. We
also analyze the production rates of scalar mesons in semileptonic decays
in the presence of mixing between scalar and glueball states. The
glueball production in meson decays is also investigated and the LHCb
experiment may discover this channel. The sizable branching fraction in , or could be a clear signal for a scalar glueball
state.Comment: 17 pages, 3 figure, revtex
Isospin Effect on the Process of Multifragmentation and Dissipation at Intermediate Energy Heavy Ion Collisions
In the simulation of intermediate energy heavy ion collisions by using the
isospin dependent quantum molecular dynamics, the isospin effect on the process
of multifragmentation and dissipation has been studied. It is found that the
multiplicity of intermediate mass fragments for the neutron-poor
colliding system is always larger than that for the neutron-rich system, while
the quadrupole of single particle momentum distribution for the
neutron-poor colliding system is smaller than that of the neutron-rich system
for all projectile-target combinations studied at the beam energies from about
50MeV/nucleon to 150MeV/nucleon. Since depends strongly on isospin
dependence of in-medium nucleon-nucleon cross section and weakly on symmetry
potential at the above beam energies, it may serve as a good probe to extract
the information on the in-medium nucleon-nucleon cross section. The correlation
between the multiplicity of intermediate mass fragments and the total
numer of charged particles has the behavior similar to , which
can be used as a complementary probe to the in-medium nucleon-nucleon cross
section.Comment: 18 pages, 9 figure
Reflection Symmetry and Quantized Hall Resistivity near Quantum Hall Transition
We present a direct numerical evidence for reflection symmetry of
longitudinal resistivity and quantized Hall resistivity
near the transition between quantum Hall state and insulator, in accord
with the recent experiments. Our results show that a universal scaling behavior
of conductances, and , in the transition regime
decide the reflection symmetry of and quantization of ,
independent of particle-hole symmetry. We also find that in insulating phase
away from the transition region deviates from the quantization and
diverges with .Comment: 3 pages, 4 figures; figure 4 is replace
Determination of InN/Diamond Heterojunction Band Offset by X-ray Photoelectron Spectroscopy
Diamond is not only a free standing highly transparent window but also a promising carrier confinement layer for InN based devices, yet little is known of the band offsets in InN/diamond system. X-ray photoelectron spectroscopy was used to measure the energy discontinuity in the valence band offset (VBO) of InN/diamond heterostructure. The value of VBO was determined to be 0.39 ± 0.08 eV and a type-I heterojunction with a conduction band offset (CBO) of 4.42 ± 0.08 eV was obtained. The accurate determination of VBO and CBO is important for the application of III-N alloys based electronic devices
The edge state network model and the global phase diagram
The effects of randomness are investigated in the fractional quantum Hall
systems. Based on the Chern-Simons Ginzburg-Landou theory and considering
relevant quasi-particle tunneling, the edge state network model for the
hierarchical state is introduced and the plateau-plateau transition and
liquid-insulator transition are discussed. This model has duality which
corresponds to the relation of the quantum Hall liquid phase and the Hall
insulating phase and reveals a mechanism in the weak coupling regime.Comment: 5 page RevTe
Scalar potential effect in an integrable Kondo model
To study the impurity potential effect to the Kondo problem in a Luttinger
liquid, we propose an integrable model of two interacting half-chains coupled
with a single magnetic impurity ferromagnetically. It is shown that the scalar
potential effectively reconciles the spin dynamics at low temperatures.
Generally, there is a competition between the Kondo coupling and the
impurity potential . When the ferromagnetic Kondo coupling dominates over
the impurity potential (), the Furusaki-Nagaosa many-body singlet can
be perfectly realized. However, when the impurity potential dominates over the
Kondo coupling (), the fixed point predicted by Furusaki and
Nagaosa is unstable and the system must flow to a weak coupling fixed point. It
is also found that the effective moment of the impurity measured from the
susceptibility is considerably enlarged by the impurity potential. In addition,
some quantum phase transitions driven by the impurity potential are found and
the anomaly residual entropy is discussed.Comment: volume enlarged, some new references are adde
- …