Narrow Results

Competitive ability of helical and two-dimensional models of generation of large-scale atmospheric hazardous events is discussed, and the conclusion is made that the helical model deserves more attention than it currently has in the world literature. A number of mechanisms of nonlinear stabilization of helical vortex instability are considered which are possible under different conditions. Intermittent nature of large-scale velocity field generated by such instability, and possibility of development of helical wave-turbulent instability are analyzed. The example of application of helical vortex instability for explanation of some phenomena observed after collision of Shoemaker-Levy 9 comet fragments with Jupiter in July 1994 is presented.

Single-walled carbon nanotubes (SWNTs) synthesized by catalytic decomposition of an alcohol were purified by extraction. The purified SWNTs were characterized on the basis of visible-near infrared (vis-NIR) absorption, photoluminescence and Raman spectroscopic analyses, scanning electron microscopy (SEM) observation, and thermal analysis. Selective extraction of metallic nanotubes was also achieved by the extraction condition.