BaTiO3 crystals, grown by Remeika method, were studied by means of acoustic emission and dielectric response. It is established, that the phase transition in the surface layer occurs on 13 °C below in comparing with the crystals bulk. It is observed, that the imaginary dielectric response of a crystal surface layer exhibits an essential smearing and slight frequency shift to higher temperatures. Reasons of such properties are discussed from a viewpoint of diffusive phase transition, taking place in the surface layer, enriched by K+ ions from KF flux.

Electromagnetic and thermal characteristics of coaxial monopole antennas of 2.45 GHz and 24.125 GHz for microwave ablation of malignant tumors are investigated. Microwave heating processes in an interaction domain (biological tissue) are described by the coupled electromagnetic and heat transfer problem, which was solved numerically in the present study. Proposed applicators provide reducing of reflected power and localized distribution of temperature in the near-field zone. Different mathematical models are used to optimize the antennas sizes and simulate heating patterns.