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1
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Memory Properties of Non-Fully Interconnected Neural Network

100%
Kosiński R. A., Zagórski A.
Acta Physica Polonica A
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1994
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vol. 86
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issue 3
427-433
EN
A model of a neural network consisting of two states neurons with the number N of (symmetric) synaptic connections per neuron treated as a variable was investigated numerically. Hebb's rule was used for storing uncorrelated patterns in the network. A maximal number of such patterns, which can be effectively retrieved by the network and the process of deterioration of the memory, is examined as a function of the number of synaptic connections per neuron. The influence of the number of neurons in the network as well as boundary conditions for the storage capacity of the network are discussed.
2
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On Efficient Field Energy Conversion in Non-Phase-Matched Frequency Doubling Process

100%
Jęda W., Zagórski A.
Acta Physica Polonica A
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2000
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vol. 98
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issue 1-2
47-53
EN
In the paper the efficiency of the light energy conversion from the fundamental wave into its second harmonics is analysed. A standard model of three waves mixing in media without centre of symmetry was applied. It was shown that the full conversion of energy is possible if an appropriate phase difference exists and provided that at least a minimal energy of the second wave is present on the input. The results are expressed both by analytical formulas and a phase space reconstruction. A simple experimental setup to enhance the second harmonics is proposed.
3
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Optical Polarisation Bistability in χ^2 Media at Large Desynchronisation Regime

100%
Jęda W., Zagórski A.
Acta Physica Polonica A
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2004
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vol. 105
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issue 4
357-363
EN
In this work we present results of calculations concerning bistability of optical polarisation in birefringent media. Second-order optical nonlinearity is assumed to be dominant and represented by one parameter. In our model the second-harmonic generation regime is assumed. Light transmission is analysed in terms of standard Fabry-Perot model of feedback. We derived formulas for the Stokes parameters describing the polarisation state. Numerical results showed that three parameters may exhibit bistable behaviour. This creates new possibilities for optical switching.
4
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Intensity and Polarisation Bistability in Two Primary-Wave Mixing in Media with Second-Order Nonlinearity

100%
Seroczyńska M., Zagórski A.
Acta Physica Polonica A
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2001
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vol. 99
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issue 6
655-663
EN
In this paper we analyse theoretically the transmission of two strong laser beams through a medium exhibiting optical nonlinearity of the second order combined with a linear anisotropy. A standard model of two wave mixing was applied and closed formulas for intensity and polarisation state were obtained. Numerical calculations show that outgoing beams are very sensitive to the state of incoming beams and to the material characteristics. Under some realistic conditions we were able to obtain bistability of both intensity and polarisation state. The results also show how to modulate the intensity and polarisation state of one wave by another one.
5
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A Model of Optical Bistability and Polarisation Evolution in Birefringent χ^{(2)} Nonlinear Media

100%
Jęda W., Zagórski A.
|
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vol. 96
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issue 3-4
373-381
EN
We present a model calculation of optical bistability and polarisation evolution in optically birefringent media based on the interaction of three waves. Second-order optical nonlinearity (described by the third rank susceptibility tensor) is assumed to be dominant. A bistable light transmission is analysed in terms of standard Fabry-Perot model of feedback, and is a direct consequence of the results obtained for a semi-infinite medium. A second effect considered in the paper is evolution of polarisation state of the waves involved in these processes. We derived a closed formula for intensity-dependent refractive index, which corresponds to that used in the case of third-order nonlinear media. As a result, we calculated both intensity and Stokes parameters of transmitted light.
6
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Nonlinear Inelastic Light Scattering in a Smectic Liquid Crystal

81%
Pura B., Jęda W., Zagórski A.
Acta Physica Polonica A
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1998
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vol. 93
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issue 3
465-470
EN
Results of measurements of the intensity of light scattered by a smectic liquid crystal are reported for three phases of the specimen. A strong dependence of the scattered intensity on the relative directions of polarization vector and molecular orientation is observed. A mechanism of light interaction with material is proposed, it is attributed to brillouin - like scattering of light on director - system excitations.
7
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On the Thermodynamics of the Hopfield Neural Network with External Field

81%
Ulaczyk J., Kosiński R., Zagórski A.
Acta Physica Polonica A
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2003
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vol. 104
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issue 5
479-486
EN
In the paper thermodynamic properties of an artificial neural network are analyzed in a way analogous to spin glasses theory. Synaptic connections are calculated numerically according to the Hebb rule and their distribution is obtained for different characteristics of stored patterns. The phase diagrams and magnetization are established in dependence on the temperature of the network and the external field (threshold). It was showed that changing control parameters typical of artificial neural network (i.e. number of stored patterns and pattern bias level) one obtains the results similar to the Sherrington-Kirkpatrick model of spin glass.
8
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Tightness and Material Aspects of Bolted Flange Connections With Gaskets of Nonlinear Properties Exposed to Variable Loads

81%
Walczak R., Pawlicki J., Zagórski A.
Archives of Metallurgy and Materials
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2016
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issue 3
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