Papers by Author: Stanislovas Marcinkevičius

Abstract: Purpose of the work is to analyze tight band coiling machine dynamics for processing wire, thread, texture, paper, leatherette or other elastic bands with a steady-state tension force. Band coiling block diagram and mathematical models for cases with one and two regulators has been made for research of elastic band coiling processing using software MATLAB-SIMULINK. Transient response curves of linear speeds in the band feed section and in a coiling machine, of band tension force and of relative elongation are presented. The digital model was used for obtaining parameters of controllers when parameters of feedback and regulators have been changing.

Abstract: We present the results of time-resolved photoluminescence (TRPL) and optically detected microwave resonance (ODMR) spectroscopy investigations of semiconductor quantum dots and quantum wells. The ODMR spectra of InAs/GaAs QDs were detected via modulation of the total intensity of the QDs emission induced by 95 GHz microwave excitation and exciton fine structure was studied. Very long life times (up to 10 ns) of photoexcited carriers were observed in this system using TRPL at low temperatures and excitation intensities promising higher responsitivity of such QDs for quantum dot infrared photodetector development. The effects of proton and alpha particles irradiation on carrier dynamics were investigated on different InGaAs/GaAs, InAlAs/AlGaAs and GaAs/AlGaAs QD and QW systems. The obtained results demonstrated that carrier lifetimes in the QDs are much less affected by proton irradiation than that in QWs. A strong influence of irradiation on the PL intensity was observed in multiple QWs after high-energy alpha particles irradiation.