Optimizing the Structure of a Production System for Activated Carbon

Russian Engineering Research - A system for the production of activated carbon is considered. The thermal deformation of its components in operation is of interest. A frame design is developed,...     

RF spectroscopy of polymer-clad silica optical fibers

Radio-frequency (RF) impedance spectroscopy has been used to measure the dielectric permittivity of a polymer coating on optical fibers. It is established that the temperature dependences of permittivity in the RF range in polymers and fused silica significantly differ. The principal possibility of independent measurements of the temperature of a polymer cladding and silica core of an optical fiber is confirmed.     

The light reflection from semiconductor heterostructures modulated by a double polarized radiofrequency field

An rf modulation optical spectroscopy method for the study of semiconductor heterostructures is suggested which employs the effect of the light reflection coefficient modulation under the action of two rf fields with different configurations. The dependence of the rf-modulated light reflection spectra at the fundamental absorption edge of a semiconductor on the rf field polarization allows various layers of the heterostructure to be selectively studied. A model is proposed that explains the features observed in the reflection spectra of the light modulated by longitudinal and transverse rf electric fields in a GaAs/AlGaAs heterostructure.     

A radio-frequency impedance spectroscope for studying interaction of high-power laser radiation with crystals

A radio-frequency impedance spectroscope for studying the interaction of high-power laser radiation with nonlinear optical crystals has been developed. It has been revealed that the shape of the piezoelectric resonance line of a crystal heated with laser radiation is identical under both uniform heating in the absence of laser radiation and nonuniform heating resulting from the action of laser radiation. This allows introduction of the notion of the equivalent crystal temperature characterizing the nonuniform temperature distribution in a crystal exposed to laser radiation.     

Identification of eigenmodes of volume piezoelectric resonators in resonant ultrasound spectroscopy

Eigenmodes of volume piezoelectric resonators used in resonant ultrasound spectroscopy (RUS) are considered. A novel method for the identification of these modes is proposed, which is based on the measurement of a temperature shift of the resonance frequency. A good coincidence of the measured and calculated eigenmode spectra is demonstrated for a quartz crystal. In comparison to the other methods of identification, the proposed approach is simple to implement and provides reliable results in solving RUS problems.