3,286 research outputs found
Duality in Complex sine-Gordon Theory
New aspects of the complex sine-Gordon theory are addressed through the
reformulation of the theory in terms of the gauged Wess-Zumino-Witten action. A
dual transformation between the theory for the coupling constant \b > 0 and
the theory for \b < 0 is given which agrees with the Krammers-Wannier duality
in the context of perturbed conformal field theory. The B\"{a}cklund transform
and the nonlinear superposition rule for the complex sine-Gordon theory are
presented and from which, exact solutions, solitons and breathers with U(1)
charge, are derived. We clarify topological and nontopological nature of
neutral and charged solitons respectively, and discuss about the duality
between the vector and the axial U(1) charges.Comment: 10 pages, LaTe
Deformed Minimal Models and Generalized Toda Theory
We introduce a generalization of -type Toda theory based on a
non-abelian group G, which we call the -Toda theory, and its affine
extensions in terms of gauged Wess-Zumino-Witten actions with deformation
terms. In particular, the affine -Toda theory describes the
integrable deformation of the minimal conformal theory for the critical Ising
model by the operator . We derive infinite conserved charges and
soliton solutions from the Lax pair of the affine -Toda theory.
Another type of integrable deformation which accounts for the
-deformation of the minimal model is also found in the gauged
Wess-Zumino-Witten context and its infinite conserved charges are given.Comment: 11pages, SNUCTP 94-83 (One reference has been added.
Analytic study of the urn model for separation of sand
We present an analytic study of the urn model for separation of sand recently
introduced by Lipowski and Droz (Phys. Rev. E 65, 031307 (2002)). We solve
analytically the master equation and the first-passage problem. The analytic
results confirm the numerical results obtained by Lipowski and Droz. We find
that the stationary probability distribution and the shortest one among the
characteristic times are governed by the same free energy. We also analytically
derive the form of the critical probability distribution on the critical line,
which supports their results obtained by numerically calculating Binder
cumulants (cond-mat/0201472).Comment: 6 pages including 3 figures, RevTe
Path Integral Bosonization of Massive GNO Fermions
We show the quantum equivalence between certain symmetric space sine-Gordon
models and the massive free fermions. In the massless limit, these fermions
reduce to the free fermions introduced by Goddard, Nahm and Olive (GNO) in
association with symmetric spaces . A path integral formulation is given
in terms of the Wess-Zumino-Witten action where the field variable takes
value in the orthogonal, unitary, and symplectic representations of the group
in the basis of the symmetric space. We show that, for example, such a path
integral bosonization is possible when the symmetric spaces are or . We also address the
relation between massive GNO fermions and the nonabelian solitons, and explain
the restriction imposed on the fermion mass matrix due to the integrability of
the bosonic model.Comment: 11 page
Vortex String Dynamics in an External Antisymmetric Tensor Field
We study the Lund-Regge equation that governs the motion of strings in a
constant background antisymmetric tensor field by using the duality between the
Lund-Regge equation and the complex sine-Gordon equation. Similar to the cases
of vortex filament configurations in fluid dynamics, we find various exact
solitonic string configurations which are the analogue of the Kelvin wave, the
Hasimoto soliton and the smoke ring. In particular, using the duality relation,
we obtain a completely new type of configuration which corresponds to the
breather of the complex sine-Gordon equation.Comment: 20 pages, 9 figure
Classical Matrix sine-Gordon Theory
The matrix sine-Gordon theory, a matrix generalization of the well-known
sine-Gordon theory, is studied. In particular, the -generalization where
fields take value in describes integrable deformations of conformal
field theory corresponding to the coset . Various
classical aspects of the matrix sine-Gordon theory are addressed. We find exact
solutions, solitons and breathers which generalize those of the sine-Gordon
theory with internal degrees of freedom, by applying the Zakharov-Shabat
dressing method and explain their physical properties. Infinite current
conservation laws and the B\"{a}cklund transformation of the theory are
obtained from the zero curvature formalism of the equation of motion. From the
B\"{a}cklund transformation, we also derive exact solutions as well as a
nonlinear superposition principle by making use of the Bianchi's permutability
theorem.Comment: 25 pages, 6 Postscript figure
Conformal Turbulence with Boundary
Based upon the formalism of conformal field theory with a boundary, we give a
description of the boundary effect on fully developed two dimensional
turbulence. Exact one and two point velocity correlation functions and energy
power spectrum confined in the upper half plane are obtained using the image
method. This result enables us to address the infrared problem of the theory of
conformal turbulence.Comment: 10pages, KHTP-93-01, SNUCTP-93-0
Analysis on dynamic tensile extrusion behavior of UFG OFHC Cu
Dynamic tensile extrusion (DTE) tests with the strain rate order of similar to 10(5) s(-1) were conducted on coarse grained (CG) Cu and ultrafine grained (UFG) Cu. ECAP of 16 passes with route B-c was employed to fabricate UFG Cu. DTE tests were carried out by launching the sphere samples to the conical extrusion die at a speed of similar to 475 m/sec in a vacuumed gas gun system. UFG Cu was fragmented into 3 pieces and showed a DTE elongation of similar to 340%. CG Cu exhibited a larger DTE elongation of similar to 490% with fragmentation of 4 pieces. During DTE tests, dynamic recrystallization occurred in UFG Cu, but not in CG Cu. In order to examine the DTE behavior of CG Cu and UFG Cu under very high strain rates, a numerical analysis was undertaken by using a commercial finite element code (LS-DYNA 2D axis-symmetric model) with the Johnson - Cook model. The numerical analysis correctly predicted fragmentation and DTE elongation of CG Cu. But, the experimental DTE elongation of UFG Cu was much smaller than that predicted by the numerical analysis. This difference is discussed in terms of microstructural evolution of UFG Cu during DTE tests.111Ysciescopu
JAK2V617F promotes replication fork stalling with disease-restricted impairment of the intra-S checkpoint response
Cancers result from the accumulation of genetic lesions, but the cellular consequences of driver mutations remain unclear, especially during the earliest stages of malignancy. The V617F mutation in the JAK2 non-receptor tyrosine kinase (JAK2V617F) is present as an early somatic event in most patients with myeloproliferative neoplasms (MPNs), and the study of these chronic myeloid malignancies provides an experimentally tractable approach to understanding early tumorigenesis. Introduction of exogenous JAK2V617F impairs replication fork progression and is associated with activation of the intra-S checkpoint, with both effects mediated by phosphatidylinositide 3-kinase (PI3K) signaling. Analysis of clonally derived JAK2V617F-positive erythroblasts from MPN patients also demonstrated impaired replication fork progression accompanied by increased levels of replication protein A (RPA)-containing foci. However, the associated intra-S checkpoint response was impaired in erythroblasts from polycythemia vera (PV) patients, but not in those from essential thrombocythemia (ET) patients. Moreover, inhibition of p53 in PV erythroblasts resulted in more gamma-H2Ax (Îł-H2Ax)âmarked double-stranded breaks compared with in like-treated ET erythroblasts, suggesting the defective intra-S checkpoint function seen in PV increases DNA damage in the context of attenuated p53 signaling. These results demonstrate oncogene-induced impairment of replication fork progression in primary cells from MPN patients, reveal unexpected disease-restricted differences in activation of the intra-S checkpoint, and have potential implications for the clonal evolution of malignancies
Luminescence Property of Rare-Earth Doped Bismuth-Borate Glasses
AbstractWe fabricated rare-earth doped bismuth borate glasses by using melt-quench technique. Two different types glass samples of xBi2O3: (100-x)B2O3 (x=30 and 50) were made to compare the luminescence properties. We measured x-ray luminescence of Bi-glass by using a x-ray tube. Several dopants were doped into the Bi-glass to measure the x-ray luminescence such as CeO2, Nd2O3, Er2O3, Dy2O3, Pr2O3, Sm2O3, Ho2O3, Gd2O3 and CeF3. Among them, Dy2O3, Nd2O3 and Sm2O3 doped Bi-glass emitted luminescence. We measured emission spectrum of each samples. Dy2O3 doped bi-glass has emission band at 482nm, 575nm, 662nm and 765nm. Nd2O3 doped bi-glass have emission band at 895nm and Sm2O3 doped Bi-glass has emission band at 569nm, 598nm, 641nm and 705nm. Moreover, Bi-glass scintillators with high light yield with good radiation hardness and low cost can be applied in high energy and nuclear physics, medical imaging, homeland security and radiation detection
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