3,629 research outputs found
Scaling Behavior of the Activated Conductivity in a Quantum Hall Liquid
We propose a scaling model for the universal longitudinal conductivity near
the mobility edge for the integer quantum Hall liquid. We fit our model with
available experimental data on exponentially activated conductance near the
Landau level tails in the integer quantum Hall regime. We obtain quantitative
agreement between our scaling model and the experimental data over a wide
temperature and magnetic field range.Comment: 9 pages, Latex, 2 figures (available upon request), #phd0
Comment on the power law in rheological equations
In conformity with the principle of shear reversal, it is proposed that the power law index in the Cross equation relating steady state viscosity to shear rate in semisolid alloy slurries should have a value of 4/3, which is independent of alloy system and the fraction solid
Robust fault detection for networked systems with communication delay and data missing
n this paper, the robust fault detection problem is investigated for a class of discrete-time networked systems with unknown input and multiple state delays. A novel measurement model is utilized to represent both the random measurement delays and the stochastic data missing phenomenon, which typically result from the limited capacity of the communication networks. The network status is assumed to vary in a Markovian fashion and its transition probability matrix is uncertain but resides in a known convex set of a polytopic type. The main purpose of this paper is to design a robust fault detection filter such that, for all unknown inputs, possible parameter uncertainties and incomplete measurements, the error between the residual signal and the fault signal is made as small as possible. By casting the addressed robust fault detection problem into an auxiliary robust H∞ filtering problem of a certain Markovian jumping system, a sufficient condition for the existence of the desired robust fault detection filter is established in terms of linear matrix inequalities. A numerical example is provided to illustrate the effectiveness and applicability of the proposed technique
The directed flow maximum near c_s=0
We investigate the excitation function of quark-gluon plasma formation and of
directed in-plane flow of nucleons in the energy range of the BNL-AGS and for
the E(Lab)=40AGeV Pb+Pb collisions performed recently at the CERN-SPS. We
employ the three-fluid model with dynamical unification of kinetically
equilibrated fluid elements. Within our model with first-order phase transition
at high density, droplets of QGP coexisting with hadronic matter are produced
already at BNL-AGS energies, E(Lab)=10AGeV. A substantial decrease of the
isentropic velocity of sound, however, requires higher energies, E(Lab)=40AGeV.
We show the effect on the flow of nucleons in the reaction plane. According to
our model calculations, kinematic requirements and EoS effects work
hand-in-hand at E(Lab)=40AGeV to allow the observation of the dropping velocity
of sound via an increase of the directed flow around midrapidity as compared to
top BNL-AGS energy.Comment: 10 pages, 4 figures; plot of p(e) at various specific entropies shows
why mixed phase is not soft at AGS energ
Experimental investigation of high temperature thermal contact resistance with interface material
Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Thermal contact resistance plays a very important role in
heat transfer efficiency and thermomechanical coupling
response between two materials, and a common method to
reduce the thermal contact resistance is to fill a soft interface
material between these two materials. A testing system of high
temperature thermal contact resistance based on INSTRON
8874 is established in the present paper, which can achieve 600
Celsius degree at the interface. Based on this system, the
thermal contact resistance between superalloy GH600 material
and three-dimensional braid C/C composite material are
experimentally investigated, under different interface pressures,
interface roughness and temperatures, respectively. At the same
time, the mechanism of reducing the thermal contact resistance
with carbon fiber sheet as interface material is experimentally
investigated. Results show that the present testing system is
feasible in the experimental research of high temperature
thermal contact resistancedc201
Cellular levels and molecular dynamics simulations of estragole DNA adducts point at inefficient repair resulting from limited distortion of the double-stranded DNA helix
Estragole, naturally occurring in a variety of herbs and spices, can form DNA adducts after bioactivation. Estragole DNA adduct formation and repair was studied in in vitro liver cell models, and a molecular dynamics simulation was used to investigate the conformation dependent (in)efficiency of N2-(trans-isoestragol-3′-yl)-2′-deoxyguanosine (E-3′-N2-dG) DNA adduct repair. HepG2, HepaRG cells, primary rat hepatocytes and CHO cells (including CHO wild-type and three NER-deficient mutants) were exposed to 50 μM estragole or 1′-hydroxyestragole and DNA adduct formation was quantified by LC–MS immediately following exposure and after a period of repair. Results obtained from CHO cell lines indicated that NER plays a role in repair of E-3′-N2-dG adducts, however, with limited efficiency since in the CHO wt cells 80% DNA adducts remained upon 24 h repair. Inefficiency of DNA repair was also found in HepaRG cells and primary rat hepatocytes. Changes in DNA structure resulting from E-3′-N2-dG adduct formation were investigated by molecular dynamics simulations. Results from molecular dynamics simulations revealed that conformational changes in double-stranded DNA by E-3′-N2-dG adduct formation are small, providing a possible explanation for the restrained repair, which may require larger distortions in the DNA structure. NER-mediated enzymatic repair of E-3′-N2-dG DNA adducts upon exposure to estragole will be limited, providing opportunities for accumulation of damage upon repeated daily exposure. The inability of this enzymatic repair is likely due to a limited distortion of the DNA double-stranded helix resulting in inefficient activation of nucleotide excision repair.</p
Magnetization and Level Statistics at Quantum Hall Liquid-Insulator Transition in the Lattice Model
Statistics of level spacing and magnetization are studied for the phase
diagram of the integer quantum Hall effect in a 2D finite lattice model with
Anderson disorder.Comment: 4 pages, 6 figure
Isoscalar Giant Dipole Resonance and Nuclear Matter Incompressibility Coefficient
We present results of microscopic calculations of the strength function,
S(E), and alpha-particle excitation cross sections sigma(E) for the isoscalar
giant dipole resonance (ISGDR). An accurate and a general method to eliminate
the contributions of spurious state mixing is presented and used in the
calculations. Our results provide a resolution to the long standing problem
that the nuclear matter incompressibility coefficient, K, deduced from sigma(E)
data for the ISGDR is significantly smaller than that deduced from data for the
isoscalar giant monopole resonance (ISGMR).Comment: 4 pages using revtex 3.0, 3 postscript figures created by Mathematica
4.
Antiflow of Nucleons at the Softest Point of the EoS
We investigate flow in semi-peripheral nuclear collisions at AGS and SPS
energies within macroscopic as well as microscopic transport models. The hot
and dense zone assumes the shape of an ellipsoid which is tilted by an angle
Theta with respect to the beam axis. If matter is close to the softest point of
the equation of state, this ellipsoid expands predominantly orthogonal to the
direction given by Theta. This antiflow component is responsible for the
previously predicted reduction of the directed transverse momentum around the
softest point of the equation of state.Comment: 13 pages LaTeX, 8 PS figures. Higher-quality PS versions of figures 3
and 4 available at
http://www.th.physik.uni-frankfurt.de/~brachman/afl3f/afl3f.htm
Water wave propagation and scattering over topographical bottoms
Here I present a general formulation of water wave propagation and scattering
over topographical bottoms. A simple equation is found and is compared with
existing theories. As an application, the theory is extended to the case of
water waves in a column with many cylindrical steps
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