800 research outputs found
Wavelet-function formation in the problem of music signal identification
Approach allowing forming wavelet-functions on the basis of periodic signals and signal fragments of musical instruments has been suggested. The required and sufficient conditions made to the formed wavelet-functions were considered. The experiment allowing identifying some harmonic components of a signal localized in time was described. The possibility of applying the developed approach in the tasks of identifying complex musical signals was show
Scalar field in a minimally coupled brane world: no-hair and other no-go theorems
In the brane-world framework, we consider static, spherically symmetric
configurations of a scalar field with the Lagrangian (\d\phi)^2/2 - V(\phi),
confined on the brane. We use the 4D Einstein equations on the brane obtained
by Shiromizu et al., containing the usual stress tensor T\mN, the tensor
\Pi\mN, quadratic in T\mN, and E\mN describing interaction with the bulk.
For models under study, the tensor \Pi\mN has zero divergence, so we can
consider a "minimally coupled" brane with E\mN = 0, whose 4D gravity is
decoupled from the bulk geometry. Assuming E\mN =0, we try to extend to brane
worlds some theorems valid for scalar fields in general relativity (GR). Thus,
the list of possible global causal structures in all models under consideration
is shown to be the same as is known for vacuum with a term in GR:
Minkowski, Schwarzschild, (A)dS and Schwarzschild-(A)dS. A no-hair theorem,
saying that, given a potential , asymptotically flat black holes
cannot have nontrivial external scalar fields, is proved under certain
restrictions. Some objects, forbidden in GR, are allowed on the brane, e.g,
traversable wormholes supported by a scalar field, but only at the expense of
enormous matter densities in the strong field region.Comment: 8 pages, Latex2e. Numerical estimates and a few references adde
Global Symmetries of Noncommutative Space-time
The global counterpart of infinitesimal symmetries of noncommutative
space-time is discussed.Comment: 7 pages, no figures; minor changes in the bibliography; final version
accepted for publication in Phys. Rev.
OPTIMIZATION OF BURNING PRODUCTION PROCESS OF CERAMSITE WITH SPECIFIED DENSITY
The paper goes into peculiarities of using developed mathematical models of ceramsite burning and computational models created on their basis. The work is done in the light of analysis and synthesis of multivariate control system of kiln angular velocity and kiln charge with volumetric thermal capacity burners. It is shown that computational models of burning as an object of control are problem-oriented on producing ceramsite with specified density. Mathematical model of ceramsite burning process as an object with distributed parameters is synthesized. The transition from model with distributed parameters to the mode with lumped parameters is performed. Then the authors used a model with three bearing cross-sections along Z-axis in Matlab software and created a computational model of multivariate object of control with inter-channel connections. The paper presents experimental computational set up methods and methods of ceramsite burning optimal curve identification on the criterion of minimizing energy consumption for burning. The developed method of staging computational experiments makes it possible to predict the strength of ceramsite if values of control actions are known. The results of modeling help create methodology of choosing optimal modes of ceramsite burning with the required mark of strength and with minimum energy consumption
Effective-Mass Dirac Equation for Woods-Saxon Potential: Scattering, Bound States and Resonances
Approximate scattering and bound state solutions of the one-dimensional
effective-mass Dirac equation with the Woods-Saxon potential are obtained in
terms of the hypergeometric-type functions. Transmission and reflection
coefficients are calculated by using behavior of the wave functions at
infinity. The same analysis is done for the constant mass case. It is also
pointed out that our results are in agreement with those obtained in
literature. Meanwhile, an analytic expression is obtained for the transmission
resonance and observed that the expressions for bound states and resonances are
equal for the energy values .Comment: 20 pages, 6 figure
Capillary-Wave Model for the Solidification of Dilute Binary Alloys
Starting from a phase-field description of the isothermal solidification of a
dilute binary alloy, we establish a model where capillary waves of the
solidification front interact with the diffusive concentration field of the
solute. The model does not rely on the sharp-interface assumption, and includes
non-equilibrium effects, relevant in the rapid-growth regime. In many
applications it can be evaluated analytically, culminating in the appearance of
an instability which, interfering with the Mullins-Sekerka instability, is
similar to that, found by Cahn in grain-boundary motion.Comment: 17 pages, 12 figure
Fluorescent visualization of NAD(P)H oxidoreductase activity in the outer mitochondrial membrane and in cytosol on acute tissue slices
Control for the parameters of a low-pressure glow discharge in argon by means of acoustic flows
© 2017, Pleiades Publishing, Ltd. The possibility to control the parameters of a low-pressure glow discharge in argon by means acoustic flows is demonstrated by numerical simulations. It is shown that such flows result in an increase in the densities of charged and excited particles in the axial region of the discharge and contraction of the positive column, while stability of the discharge is preserved
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