1,235 research outputs found
Complex conductivity in strongly fluctuating layered superconductors
The time-dependent Ginzburg-Landau approach is used to calculate the complex
fluctuation conductivity in layered type-II superconductor under magnetic
field. Layered structure of the superconductor is accounted for by means of the
Lawrence-Doniach model, while the nonlinear interaction term in dynamics is
treated within self-consistent Gaussian approximation. In high-
materials, large portion of the diagram belongs to vortex liquid phase.
The expressions summing contributions of all the Landau levels are presented in
explicit form which are applicable essentially to the whole phase and are
compared to experimental data on high- superconductor
YBaCuO. Above the crossover to the "normal phase",
our results agree with the previously obtained.Comment: 8 pages, 1 figur
The weak Lefschetz property of artinian algebras associated to paths and cycles
Given a base field of characteristic zero, for each graph , we
associate the artinian algebra defined by the edge ideal of and the
squares of the variables. We study the weak Lefschetz property of . We
classify some classes of graphs with relatively few edges, including paths and
cycles, such that its associated artinian ring has the weak Lefschetz property.Comment: 21 pages. Comments are welcome
Effects of foundation mass on dynamic responses of beams subjected to moving oscillators
This paper aims at the effects of foundation mass on the dynamic responses of beams subjected to moving oscillators. To achieve this aim, experiments were performed for a beam resting on the foundation considering effects of the foundation model including linear elastic spring, shear layer, viscous damping. In addition, special effects of mass density of foundation during vibration were established to obtain the characteristic parameter of the influence of foundation mass based on natural circular frequency of the structure system determined from FFT plots of the time history of acceleration data. Furthermore, the experimental parameters were used to analyze the influence of the foundation mass on the dynamic response of the beam subjected to moving oscillator. Comparisons between experimental and simulated results showed that the foundation mass showed significant effects on the dynamic characteristic response of the beam system. It increased the general vibrating mass of the structure system. Hence, it decreased of the natural frequency of the structural system and caused a significant increase on the dynamic response of the beam when compared with the case without considering the foundation mass. Finally, the relationships between the foundation properties and the parameters of foundation mass were derived and discussed
The influence of foundation mass on dynamic response of track-vehicle interaction
The influence of foundation mass on the dynamic response of track-vehicle interaction is studied in this paper. The moving vehicle is modeled as a two-axle mass-spring-damper four-degrees-of-freedom system. A new dynamic foundation model, called "Dynamic foundation model" including linear elastic spring, shear layer, viscous damping and foundation mass parameter, is used to analyze the dynamic response of the track-vehicle interaction. The railway track on the new dynamic foundation model subjected to a moving vehicle is regarded as an integrated system. By means of the finite element method and dynamic balance principle, the governing equation of motion for railway track-vehicle-foundation interaction is derived and solved by the step-by-step integration method. The accuracy of the algorithm is verified by comparing the numerical results with the other numerical results in the literature. The influence of foundation mass parameter on the dynamic response of railway track-vehicle interaction is investigated. The numerical results show that with the new dynamic foundation model the foundation mass effects more significantly on the dynamic response of track-vehicle interaction. The study shows that the new dynamic foundation model describes the true behavior of soil in the analysis of dynamic response of structures on the foundation
Critical Crossover Between Yosida-Kondo Dominant Regime and Magnetic Frustration Dominant Regime in the System of a Magnetic Trimer on a Metal Surface
Quantum Monte Carlo simulations were carried out for the system of a magnetic
trimer on a metal surface. The magnetic trimer is arranged in two geometric
configurations, viz., isosceles and equilateral triangles. The calculated
spectral density and magnetic susceptibility show the existence of two phases:
Yosida-Kondo dominant phase and magnetic frustration dominant phase.
Furthermore, a critical transition between these two phases can be induced by
changing the configuration of the magnetic trimers from isosceles to
equilateral triangle.Comment: 8 pages, 4 figures; accepted for publication in J. Phys. Soc. Jp
Adversarial Patch Generation for Automatic Program Repair
Automatic program repair (APR) has seen a growing interest in recent years
with numerous techniques proposed. One notable line of research work in APR is
search-based techniques which generate repair candidates via syntactic analyses
and search for valid repairs in the generated search space. In this work, we
explore an alternative approach which is inspired by the adversarial notion of
bugs and repairs. Our approach leverages the deep learning Generative
Adversarial Networks (GANs) architecture to suggest repairs that are as close
as possible to human generated repairs. Preliminary evaluations demonstrate
promising results of our approach (generating repairs exactly the same as human
fixes for 21.2% of 500 bugs).Comment: Submitted to IEEE Software's special issue on Automatic Program
Repair. Added reference
Weighted monotonicity inequalities for traces on operator algebras
We study inequalities of the form, where τ is a trace on a von Neumann algebra or a C*-algebra, A and B are self-adjoint elements of the algebra in question, f and w are real-valued functions, and the "weight" function w is nonnegative. © 2010 Pleiades Publishing, Ltd
To the theory of operator monotone and operator convex functions
We prove that a real function is operator monotone (operator convex) if the corresponding monotonicity (convexity) inequalities are valid for some normal state on the algebra of all bounded operators in an infinite-dimensional Hilbert space. We describe the class of convex operator functions with respect to a given von Neumann algebra in dependence of types of direct summands in this algebra. We prove that if a function from ℝ+ into ℝ+ is monotone with respect to a von Neumann algebra, then it is also operator monotone in the sense of the natural order on the set of positive self-adjoint operators affiliated with this algebra. © 2010 Allerton Press, Inc
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