Harmonic generation enhancement due to interaction of few-cycle light pulses in nonlinear dielectric coating on a mirror

We theoretically investigate reflection of a few-cycle light pulse from a mirror with nonlinear dielectric coating. We employ a nonlinear equation that describes spatiotemporal evolution of a few-cycle light pulse with a broad spectrum that lies in the transparency range of nonlinear dielectric media. This model is formulated directly for the electric field without slowly varying amplitude approximation. Analytical and numerical analysis shows that counter-propagating wave interactions in thin films can strongly enhance or suppress third harmonic generation of the central frequency, whereas this effect is neglected in the framework of slowly varying amplitude approximation

Bag-breakup fragmentation as the dominant mechanism of sea-spray production in high winds

Peer reviewe

Event-driven simulation of the state institution activity for the service provision based on business processes

The paper presents an approach, based on business processes, assessment and control of the state of the state institution, the social insurance Fund. The paper describes the application of business processes, such as items with clear measurable parameters that need to be determined, controlled and changed for management. The example of one of the business processes of the state institutions, which shows the ability to solve management tasks, is given. The authors of the paper demonstrate the possibility of applying the mathematical apparatus of imitative simulation for solving management tasks

Flat liquid jet as a highly efficient source of terahertz radiation

Polar liquids are strong absorbers of electromagnetic waves in the terahertz range, therefore, historically such liquids have not been considered as good candidates for terahertz sources. However, flowing liquid medium has explicit advantages, such as a higher damage threshold compared to solid-state sources and more efficient ionization process compared to gases. Here we report systematic study of efficient generation of terahertz radiation in flat liquid jets under sub-picosecond single-color optical excitation. We demonstrate how medium parameters such as molecular density, ionization energy and linear absorption contribute to the terahertz emission from the flat liquid jets. Our simulation and experimental measurements reveal that the terahertz energy has quasi-quadratic dependence on the optical excitation pulse energy. Moreover, the optimal pump pulse duration, which depends on the thickness of the jet is theoretically predicted and experimentally confirmed. The obtained optical-to-terahertz energy conversion efficiency is more than 0.05%. It is comparable to the commonly used optical rectification in most of electro-optical crystals and two-color air filamentation. These results, significantly advancing prior research, can be successfully applied to create a new alternative source of terahertz radiation

Synthesis, recyclization under the action of methanol and analgetic activity of N'-(5-aryl-2-oxofuran-3(2H)-ylidene)furan-2-carbohydrazides

New methyl 5-aryl-1-(furan-2-carbonyl)-1H-pyrazole-3-carboxylates were obtained via decyclization reaction of N'-(5-aryl-2-oxofuran-3(2H)-ylidene)furan-2-carbohydrazides under the action of methanol. Starting N'-(5-aryl-2-oxofuran-3(2H)-ylidene)furan-2-carbohydrazides were obtained by intramolecular cyclization of substituted 4-aryl-2-[2-(furan-2-ylcarbonyl)hydrazinylidene]-4-oxobutanoic acids in propionic anhydride. The structure of the compounds obtained was confirmed by the 1H NMR spectroscopy, IR spectrometry and elemental analysis methods. Analgesic activity of some obtained compounds was studied by the “hot plate” method on outbred white mice of both sexes with intraperitoneal injection

Sensitivity to a possible variation of the proton-to-electron mass ratio torsion-wagging-rotation transitions in methylamine CH3NH2

9 x 10(-6) is deduced

Three Dimensional Relativistic Electromagnetic Sub-cycle Solitons

Three dimensional (3D) relativistic electromagnetic sub-cycle solitons were observed in 3D Particle-in-Cell simulations of an intense short laser pulse propagation in an underdense plasma. Their structure resembles that of an oscillating electric dipole with a poloidal electric field and a toroidal magnetic field that oscillate in-phase with the electron density with frequency below the Langmuir frequency. On the ion time scale the soliton undergoes a Coulomb explosion of its core, resulting in ion acceleration, and then evolves into a slowly expanding quasi-neutral cavity.Comment: 5 pages, 6 figures; http://www.ile.osaka-u.ac.jp/research/TSI/Timur/soliton/index.htm

Wearable laser Doppler sensors for evaluating the nutritive and shunt blood flow

This study is devoted to the trials of wearable diagnostic system that implements the laser Doppler flowmetry technique to analyse the blood microcirculation. We do preliminary test with involvement of limited group of healthy volunteers of different age and in patients with type 2 diabetes. During the series of measurements, the microcirculation parameters was measured for 10 minutes in the palmar surfaces of the big toes and in the inner sides of the upper thirds of the shins. A statistically significant differences was found in bypass index, nutritive and shunt blood ow in shins between older group of volunteers and patients' group as well as in shunt blood flow in fingers between younger and older groups of volunteers