RESUMO
It is shown that the impedance spectroscopy allows identification of the resistive switching mechanisms in complex composite structures. This statement was demonstrated on an example of organic based sandwich structures with a modified polymer matrix as an active element. The impedance spectroscopy scanning was performed for a series of intermediate states formed within the switching process. Analysis of the experimentally obtained impedance spectra shows that the electron transport is provided by delocalized charge carriers and proceeds via conducting filaments formed in a highly resistive matrix. The filament configuration changes during the switching. With the shift from isolating to conducting states, single isolated filaments are reorganized into a branched network.
RESUMO
Use of organic dyes for improvement of the efficiency and targeting accuracy of laser treatment of biological tissues is considered. It is shown that some organic materials provide effective protection of adjacent tissues by reducing the intensity of optical radiation outside the laser surgery site. They also can eliminate the detrimental effect of random reflections of intense laser radiation upon its passage through semitransparent cartilaginous tissue. Advantages of diphthalocyanine dyes (broad spectral region of radiation absorption, high resistance to heat and light, solubility in low-toxic organic dyes) are described.
