The outbursts of cometary brightness háve been attracting the astronomers attention for more than a hundred of years. They play a significant role in the study of physical nature and evolution of comets. An outstanding Soviet astronomer S.K. Vsekhsvyatsky (i)
pointed out the corpuscular fluxes as a plausible factor being responsible for the variation of cometary brightness. He was the
first to suggest that the effect of fragmentation of solar corpuscular fluxes on cometary ices is one of the causes generating the
brightness outbursts.
Effects of excess Cd and Cu on the contents of total glutathione and phytochelatin (PC) were measured in roots and leaves of intact spinách piants. The total glutathione levels declined with the PCs synthesis. The kinetic data indicated that the shorter PCs were substrates for the longer PCs. PCs appear much earlier in roots than in leaves of intact spinách piants. The PC formation was stimulated most effectively by Cd, less so by Cu.
Processes development for production of the Metis coronagraph lightweight mirrors represented with respect to high shape accuracy and surface micro-roughness requirements challenging engineering tasks. One of many serious problems, which we need to solve, was a low optical surface shape stability manifesting by unmanageable shape deformations. As we found, the reason was in chosen cementing process. With using of FEM simulations for the cementing process analysing and the mirror holder redesign the residual stress generated by temperature changes was suppressed and the shape deformation of the optical surface was reduced below the critical limit of about 100 nm. and Výroba odlehčených letových kusů zrcadel koronografu Metis s vysokými nároky na tvarovou přesnost a mikrodrsnost optické plochy představovala náročný inženýrský úkol. Jedním z úskalí, s kterým se musel řešitelský tým Centra Toptec vyrovnat, byla problematická tvarová stabilita optické plochy projevující se nekontrolovatelnými deformacemi v průběhu broušení a leštění. Jak bylo zjištěno, příčinou byl zvolený způsob tmelení. S využitím FEM simulací, na jejichž základě byl předělán design tmelky, se podařilo minimalizovat teplotními změnami generovanou zbytkovou napjatost a potlačit tak deformace pod kritickou hranici 100 nm PV, kdy z pohledu splnění specifikované tvarové přesnosti nepředstavovala zásadní problém.