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Nonlinear Optical Experiments on Liquid Crystal Chiral Structures
No full textabstractEN: Abstract Up to now there are only few reports in the literature on experimental examination of nonlinear effects in chiral liquid crystals. The presented data are sometimes confusing. We proposed a simple experiment in a probe+pump laser technics for studying periodic liquid crystalline structures. The paper presents initial results of examination of a cholesteric material in the region of selective light reflection. We have been interested if any nonlinear effect of the collective nature appeared by usually accessible light intensities, i.e. non-thermal but of optical reorientation origin. The investigation was oriented toward potential application in all-optical light modulators.score: 0collation: 139-14
Numerical simulation of beam propagation in a layer filled with chiral nematic liquid crystals
No full textabstractEN: Numerical simulation of beam propagation in a layer filled with chiral nematic liquid crystalsscore: 7collation: 163-16
Coupled solitons in waveguides with second- and third-order nonlinearities
No full textabstractEN: The analytical form of coupled temporal solitons in waveguides with second- and third-order nonlinearities is presented. The solutions are obtained for group-velocity dispersions of the same sign for both fundamental and second-harmonic frequencies. In particular, three types of coupled soliton are found: bright solitons, which can exist in materials with second- or third-order nonlinearities; semidark (twin-hole) solitons, which require materials with second-order nonlinearity; and gray coupled solitons existing only in materials with both nonvanishing nonlinearities.score: 40collation: 1677-167
The Time Domain Spectroscopygoniometric setup characterization by the utilization of the plastic diffraction grating
No full textabstractEN: The Time Domain Spectroscopygoniometric setup characterization by the utilization of the plastic diffraction gratingscore: 7collation: 121-12
Evolution of supergaussian pulses in nonlinear Kerr media
No full textabstractEN: Evolution of supergaussian pulses in nonlinear Kerr mediascore: 7collation: 178-18
The Lehman Brothers effect and bankruptcy cascades
No full textabstractEN: Inspired by the bankruptcy of Lehman Brothers and its consequences on the global financial system, we develop a simple model in which the Lehman default event is quantified as having an almost immediate effect in worsening the credit worthiness of all financial institutions in the economic network. In our stylized description, all properties of a given firm are captured by its effective credit rating, which follows a simple dynamics of co-evolution with the credit ratings of the other firms in our economic network. The dynamics resembles the evolution of Potts spin-glass with external global field corresponding to a panic effect in the economy. The existence of a global phase transition, between paramagnetic and ferromagnetic phases, explains the large susceptibility of the system to negative shocks. We show that bailing out the first few defaulting firms does not solve the problem, but does have the effect of alleviating considerably the global shock, as measured by the fraction of firms that are not defaulting as a consequence. This beneficial effect is the counterpart of the large vulnerability of the system of coupled firms, which are both the direct consequences of the collective self-organized endogenous behaviors of the credit ratings of the firms in our economic network.score: 25collation: 257-26
Damping of Vibrations in a SystemWith Two Beams by Structural Friction
No full textabstractEN: This paper presents the results of tests on free and forced harmonic vibrations in a system with two beams with structural friction taken into account. The beams are clamped together with uniform unitary pressure. The hysteresis loop describing the frictional-elastic properties of the system has a form of a parallelogram. The autor created a mathematical model of the vibrating system with two beams. During free vibrations of the system, its damping characteristics were tested by a digital simulation method. The vibration damping decrement as a function of amplitude displacement was determined. When vibrations were harmonically forced, the amplitude - frequency characteristics of the system were determined numerically. The system was used as a nonlinear vibration damper in a linear system with a harmonic force. The equations of motion of the nonlinear two-degree of freedom system were solved by means of a digital simulation method. (© 2005 WILEY-VCH Verlag GmbH \& Co. KGaA, Weinheim)score: 0collation: 99–10
An Effective 2D Linear Elasticity Vibrational Model for Layered and Sandwich Clamped-Clamped Unidirectional Strips
No full textabstractEN: An effective new model for vibration analysis of the layered, and in particular sandwich, one-span, clamped-clamped (C-C) strips and beams is presented in the paper. The model is derived directly from the local linear elasticity model (solution) for the corresponding simply supported (S-S) structures after replacing the Fourier sinus series eigenfunctions with the Bernoulli-Euler eigenfunctions. The approach is verified by comparisons of numerical results obtained with the data available in the literature. Number of layers is unlimited but the model was elaborated for the structures composed of five layers.score: 3collation: 577-58
Animated visualization of the maximum material requirement
No full textabstractEN: The usage of animation technique applied as a powerful tool to explain the complex concept of the maximum material requirement (MMR) is shown. The concepts of datum system and the maximum material virtual condition envelope, that is located by theoretically exact dimensions are highlighted. The maximum material virtual condition state, that limits the collective effect of the feature maximum material size and the maximum acceptable geometrical deviation for that size is examined. The tolerances of perpendicularity and position with the maximum material modifiers applied in the tolerance frames for the toleranced features or respectively for the datum features are explored. The simplicity of the verification of the conformance with the specification employing the MMR by the gauge that represents the matting counter part is emphasized.score: 25collation: 2283-228
