Midinfrared optical breakdown in transparent dielectrics

Optical breakdown measurements for transparent dielectrics are reported for 1 ps laser pulses as a function of mid-IR wavelength from 4.7 to 7.8 microm. For wide-gap dielectrics seed electrons are generated by tunnel ionization with subsequent avalanche ionization and laser absorption by dense plasma. For narrow-gap dielectrics tunnel ionization alone leads to dense plasma formation.     

Onset of thermocapillary convection in a two-layer system with the release of heat at the interface

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 1, pp. 69–73, January–February, 1990.     

Baryon pairs production ine + e − annihilation at\sqrt s = 2.4 GeV

Search for baryon pairs production ine ⁺ e ^? annihilation at \(\sqrt s = 2386 MeV\) is reported. The data relate to a luminosity of 161 nb^?1 collected by the DM2 experiment at DCI, the Orsay colliding ring. First measurements of directe ⁺ e ^? annihilation into \(\Lambda \bar \Lambda \) and ofe ⁺ e ^?→ \(p\bar p\) at this energy are presented. First observation of a goode ⁺ e ^?→ \(n\bar n\) candidate is reported and upper limits are given fore ⁺ e ^?→ \(n\bar n, \Lambda \bar \sum ^0 + c.c.\) and \(\Sigma ^0 \bar \Sigma ^0 \) .     

Nonlinear convective oscillations in multilayer systems

The joint action of buoyancy and the thermocapillary effect in two- and three-layer systems, is studied. Two types of boundary conditions, periodic boundary conditions and rigid heat–insulated lateral walls, are considered. In the case of periodic boundary conditions, regimes of traveling waves have been found. In the case of rigid heat-insulated lateral walls, symmetric and asymmetric standing waves are observed. Transitions between different types of oscillatory motions are studied. The competition between buoyancy and the thermocapillary effect in a three-layer system may lead to the complex dynamics and different unexpected effects. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spiral thermocapillary flows in two-layer systems

Parallel thermocapillary flows in infinite layers can be calculated easily. However, in reality thermocapillary flows occur in channels or closed cavities, and they are three-dimensional. In the present paper, a two-layer fluid system filling a channel with a rectangular cross section is considered. A numerical investigation of three-dimensional spiral thermocapillary flows generated by a temperature gradient imposed along the channel has been performed. Both the case of a zero longitudinal pressure gradient (a through flow in the channel) and that of a zero longitudinal fluid flux (a flow in the closed cavity) are investigated. Steady and oscillatory thermocapillary motions, and transitions between them are studied.     

Occurrence of thermocapillary convection in a two-layer system in the presence of a soluble surfactant

The present study considers the effect of the solubility of a surfactant on monotonic oscillatory thermocapillary instability of equilibrium in a two-layer system. It is established that with increase in the parameter which characterizes the solubility of the surfactant a reduction takes place in the threshold of the monotonic instability; finally the monotonic perturbations become most dangerous.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 171–175, March–April, 1988.     

Onset of convection due to heating from above and heat release at an interface

A specific non-Rayleigh mechanism of convective instability in systems with an interface, developing in the presence of heating from above (anticonvection), was identified in [1, 2]. The onset of this type of instability requires a sharp difference in the physical parameters of the fluids. The effect of heat release and heat absorption on the onset of convection in systems for which this instability mechanism is possible is examined. In the presence of surface heat sources the directions of the temperature gradients in the two media may be different. The interaction of Rayleigh and non-Rayleigh types of instability is investigated. It is shown that for the water-mercury system on a certain interval of the parameters the oscillatory mode of instability is the most dangerous.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 16–20, May–June, 1990.