... Physical Properties of Crystals . ... The course is an introduction into crystal physics and consists of two introductory parts devoted to the basics of crystallography and tensor analysis and six main chapters in which the physical phenomena in anisotropic medium are described by the example of the elastic, electrical and magnetic crystal properties. The effect of symmetry is also discussed. ... Effect of symmetry on crystal properties. ... Effect of symmetry on crystal optical properties. ...

The efficiency of interaction of radiation with a particle and hence its optical properties depend on the particle chemical composition, size, shape, structure, etc. ... Particle size expressed in units of the wavelength of incident radiation, together with chemical composition, most strongly affects the optical properties of a scatterer. ... There are many methods to solve the light-scattering problem for a homogeneous spheroid (our survey of the light-scattering methods see here ). ...

Next: EVOLUTION MODELS Up: EXTREME HELIUM STARS: PULSATION Previous: EXTREME HELIUM STARS . The characteristic surface properties, effective temperature , surface gravity and composition , of EHes have been summarized by Jeffery (1996). ... Helium: ( ) By definition, helium dominates the atmospheric abundances. ... This is supported by a correlation between N and Fe abundances in EHes. ... Next: EVOLUTION MODELS Up: EXTREME HELIUM STARS: PULSATION Previous: EXTREME HELIUM STARS Simon Jeffery . ...

... Unsafe act - a behavioral departure from an accepted, normal, or correct procedure or practice which, in the past, has produced injury or property damage or which has potential for doing so in the future; an unnecessary exposure to a hazard; conduct reducing the degree or safety normally present in an activity. ... Any hazardous unsafe condition, or act that presents a situation of imminent danger to life and/or property requires urgent action. ...

... The Science Operation Department is composed of Astronomers, Telescope Instruments Operators(TIOs) and Data Handling Administrators(DHAs). ... Astronomers have proposed several methods to quantitatively measure the amount of turbulence above the telescope, which the most common ones is Differential Image Motion Monitor (DIMM). In optical testing, the Hartmann test is the common method to test the quality of optical components. ... Hartmann mask consists of 48 lenses. ...