Geodesic Flow on the Normal Congruence of a Minimal Surface

We study the geodesic flow on the normal line congruence of a minimal surface in ${\Bbb{R}}^3$ induced by the neutral K\"ahler metric on the space of oriented lines. The metric is lorentz with isolated degenerate points and the flow is shown to be completely integrable. In addition, we give a new holomorphic description of minimal surfaces in ${\Bbb{R}}^3$ and relate it to the classical Weierstrass representation.Comment: AMS-LATEX 8 pages 2, figure

On the Cooling of Electrons in a Silicon Inversion Layer

The cooling of two-dimensional electrons in silicon-metal-oxide semiconductor field effect transistors is studied experimentally. Cooling to the lattice is found to be more effective than expected from the bulk electron-phonon coupling in silicon. Unexpectedly, the extracted heat transfer rate to phonons at low temperatures depends cubically on electron temperature, suggesting that piezoelectric coupling (absent in bulk silicon) dominates over deformation potential. According to our findings, at 100 mK, electrons farther than 0.1 mm from the contacts are mostly cooled by phonons. Using long devices and low excitation voltage we measure electron resistivity down to 100 mK and find that some of the "metallic" curves, reported earlier, turn insulating below about 300 mK. This finding renders the definition of the claimed 2D metal-insulator transition questionable. Previous low temperature measurements in silicon devices are analyzed and thumb rules for evaluating their electron temperatures are provided.Comment: 5 pages, 4 figures. Discussion corrected and a few references adde

Students professional orientation to the teaching profession in educational environment

© 2016 by iSER, International Society of Educational Research.Properly organized pedagogical career guidance for young people can be considered as a means of younger generation’s educational culture increasing, and hence the humanization of the entire society. The purpose of the paper is to reveal the two directions’ contents of the pupils’ pedagogical orientation: pre-professional teacher training in the school and the organization of students’ professional orientation at the University. A leading approach to the study of this problem is a systematic approach involving the relationship of the content, forms and methods of students’ pedagogical orientation as well as interaction of this process’s entities. The paper reveals the content of the developed curriculum for students’ pre-professional pedagogical training, and analyzes the possibilities of interaction between school and University as a factor in the students’ determination in the teaching profession. The paper can be useful for educators who are engaged in students’ professional orientation to the teaching profession