Optical breakdown on a target surface under a simultaneous laser pulse action at the wavelength of 248 and 532 nm

It is found that under, a double-pulse optical breakdown, the energy of the main pulse with a wavelength of 532 nm is diminished by up to two times, provided that the preionization of the target surface is performed by a laser pulse with a wavelength of 248 nm. It is shown that the pulse of a shorter wavelength can act as the managing one to specify the optical-breakdown onset and coordinates.     

Developing Methods for Producing Hydrophobized Platinum Catalysts of Different Types

Theoretical Foundations of Chemical Engineering - The development of a thermostable hydrophobic platinum catalyst is an important scientific and practical problem. The purpose of this work is to...     

Fiber optic fluorometer with dipping module

A fiber optic fluorometer with dipping module intended for use in studying the contents of phytoplankton in sea water at different depths is described. Using the device, it is possible to carry out continuous measurements under the conditions of the strongly variable illuminance of the sea. Results of measurements of the fluorescence of sea water by means of the newly developed fluorometer are presented. __________ Translated from Izmeritel’naya Tekhnika, No. 1, pp. 27–29, January, 2008.     

Excitation of polyharmonic vibrations in single-body vibration machine with inertia drive and elastic clutch

The authors analyze excitability of polyharmonic vibrations in a single-body vibration machine. The developed mathematical model of the vibration system accounts for an elastic component element included in the design of the unbalance vibration exciter drive. The operating limits, frequency content and effect of the main design factors on the flow data of the vibration machine are examined. It is found that superharmonic vibration largely contributes to the polyharmonic spectrum at certain frequencies, depending on the stiffness of the elastic component element of the clutch connecting the vibration exciter and the rotary drive.     

Angular diagram of broadband emission of millimeter-sized water droplets exposed to gigawatt femtosecond laser pulses

We report on the experiments on the interaction of gigawatt femtosecond laser pulses with suspended millimeter-sized water droplets. The transparent droplets experienced laser-induced breakdown and explosive boiling up and emitted a broadband radiation. This radiation covers the spectral range from 450 to 1100?nm and consists of the spectrum of laser pulse scattered and transformed by the droplet due to self-phase modulation and plasma emission produced in water during photoionization. The droplet emission spectrum showed remarkable broadening at all viewing angles and is maximal in the direction of the laser exit from the droplet. The enlargement of the droplet results in additional spectral spreading of the emitted radiation. The depth and amount of laser pulse spectral self-transformations upon propagation through the water droplet are simulated by means of numerical calculations.     

Sintering quartz ceramics in vacuum

Conclusions During sintering in vacuum the porosity and gas permeability of the material sharply diminishes, and the strength is increased. Firing at 1250°C in vacuum produces high-density specimens with a porosity of about 2%, and with a compressive strength of 60 kg/mm².Translated from Ogneupory, No. 8, pp. 62–65, August, 1971.