251 research outputs found
Phenomenological Scaling of Rapidity Dependence for Anisotropic Flows in 25 MeV/nucleon Ca + Ca by Quantum Molecular Dynamics Model
Anisotropic flows (, , and ) of light fragments up till
the mass number 4 as a function of rapidity have been studied for 25
MeV/nucleon Ca + Ca at large impact parameters by Quantum
Molecular Dynamics model. A phenomenological scaling behavior of rapidity
dependent flow parameters (n = 1, 2, 3 and 4) has been found as a
function of mass number plus a constant term, which may arise from the
interplay of collective and random motions. In addition, keeps
almost independent of rapidity and remains a rough constant of 1/2 for all
light fragments.Comment: 4 pages, 5 figure
Edge states and topological orders in the spin liquid phases of star lattice
A group of novel materials can be mapped to the star lattice, which exhibits
some novel physical properties. We give the bulk-edge correspondence theory of
the star lattice and study the edge states and their topological orders in
different spin liquid phases. The bulk and edge-state energy structures and
Chern number depend on the spin liquid phases and hopping parameters because
the local spontaneous magnetic flux in the spin liquid phase breaks the time
reversal and space inversion symmetries. We give the characteristics of bulk
and edge energy structures and their corresponding Chern numbers in the
uniform, nematic and chiral spin liquids. In particular, we obtain analytically
the phase diagram of the topological orders for the chiral spin liquid states
SL[\phi,\phi,-2\phi], where \phi is the magnetic flux in two triangles and a
dodecagon in the unit cell. Moreover, we find the topological invariance for
the spin liquid phases, SL[\phi_{1},\phi_{2},-(\phi_{1}+\phi_{2})] and
SL[\phi_{2},\phi_{1},-(\phi_{1}+\phi_{2})]. The results reveal the relationship
between the energy-band and edge-state structures and their topological orders
of the star lattice.Comment: 7 pages, 8 figures, 1 tabl
Strong quantum fluctuation of vortices in the new superconductor
By using transport and magnetic measurement, the upper critical field
and the irreversibility line has been determined. A
big separation between and has been found showing the
existence of a quantum vortex liquid state induced by quantum fluctuation of
vortices in the new superconductor . Further investigation on the
magnetic relaxation shows that both the quantum tunneling and the thermally
activated flux creep weakly depends on temperature. But when the melting field
is approached, a drastic rising of the relaxation rate is observed.
This may imply that the melting of the vortex matter at a finite temperature is
also induced by the quantum fluctuation of vortices.Comment: 4 pages, 4 figure
Common Features in Electronic Structure of the Fe-Based Layered Superconductors from Photoemission Spectroscopy
High resolution photoemission measurements have been carried out on
non-superconducting LaOFeAs parent compound and various superconducting
R(O1-xFx)FeAs (R=La, Ce and Pr) compounds. We found that the parent LaOFeAs
compound shows a metallic character. Through extensive measurements, we have
identified several common features in the electronic structure of these
Fe-based compounds: (1). 0.2 eV feature in the valence band; (2). A universal
13~16 meV feature; (3). A clear Fermi cutoff showing zero leading-edge shift in
the superconducting state;(4). Lack of superconducting coherence peak(s); (5).
Near EF spectral weight suppression with decreasing temperature. These
universal features can provide important information about band structure,
superconducting gap and pseudogap in these Fe-based materials.Comment: 5 pages,4 figure
A Two-Step Hydrothermal Synthesis Approach to Monodispersed Colloidal Carbon Spheres
This work reports a newly developed two-step hydrothermal method for the synthesis of monodispersed colloidal carbon spheres (CCS) under mild conditions. Using this approach, monodispersed CCS with diameters ranging from 160 to 400 nm were synthesized with a standard deviation around 8%. The monomer concentration ranging from 0.1 to 0.4 M is in favor of generation of narrower size distribution of CCS. The particle characteristics (e.g., shape, size, and distribution) and chemical stability were then characterized by using various techniques, including scanning electron microscopy (SEM), FT-IR spectrum analysis, and thermalgravity analysis (TGA). The possible nucleation and growth mechanism of colloidal carbon spheres were also discussed. The findings would be useful for the synthesis of more monodispersed nanoparticles and for the functional assembly
Overexpression and Small Molecule-Triggered Downregulation of CIP2A in Lung Cancer
Lung cancer is the leading cause of cancer deaths worldwide, with a five-year overall survival rate of only 15%. Cancerous inhibitor of PP2A (CIP2A) is a human oncoprotein inhibiting PP2A in many human malignancies. However, whether CIP2A can be a new drug target for lung cancer is largely unclear.Normal and malignant lung tissues were derived from 60 lung cancer patients from southern China. RT-PCR, Western blotting and immunohistochemistry were used to evaluate the expression of CIP2A. We found that among the 60 patients, CIP2A was undetectable or very low in paratumor normal tissues, but was dramatically elevated in tumor samples in 38 (63.3%) patients. CIP2A overexpression was associated with cigarette smoking. Silencing CIP2A by siRNA inhibited the proliferation and clonogenic activity of lung cancer cells. Intriguingly, we found a natural compound, rabdocoetsin B which is extracted from a Traditional Chinese Medicinal herb Rabdosia coetsa, could induce down-regulation of CIP2A and inactivation of Akt pathway, and inhibit proliferation and induce apoptosis in a variety of lung cancer cells.Our findings strongly indicate that CIP2A could be an effective target for lung cancer drug development, and the therapeutic potentials of CIP2A-targeting agents warrant further investigation
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