Microscopic surface structure of C/SiC composite mirrors for space cryogenic telescopes

We report on the microscopic surface structure of carbon-fiber-reinforced silicon carbide (C/SiC) composite mirrors that have been improved for the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) and other cooled telescopes. The C/SiC composite consists of carbon fiber, silicon carbide, and residual silicon. Specific microscopic structures are found on the surface of the bare C/SiC mirrors after polishing. These structures are considered to be caused by the different hardness of those materials. The roughness obtained for the bare mirrors is 20 nm rms for flat surfaces and 100 nm rms for curved surfaces. It was confirmed that a SiSiC slurry coating is effective in reducing the roughness to 2 nm rms. The scattering properties of the mirrors were measured at room temperature and also at 95 K. No significant change was found in the scattering properties through cooling, which suggests that the microscopic surface structure is stable with changes in temperature down to cryogenic values. The C/SiC mirror with the SiSiC slurry coating is a promising candidate for the SPICA telescope.Comment: 25 pages, 6 figure

Warranted Skepticism: A Dynamic Model of Infant Industry Protection

The neo-classical model of infant industry protection is limited in that agents have static expectations. This paper incorporates a fundamental behavioral assumption, that agents base their decisions on future expectations. An analysis of the global perfect foresight dynamics exposes the rich relationship between protection and outcome, and new policy implications. If an industry is to be protected until its good is competitive in the world market, its success is as likely as its failure, explaining the unreliability of protection programs in practice. The industry's decline after an initial take-off can also be an equilibrium. For the industry's growth to be an equilibrium, protection can be removed before the industry achieves international competitiveness. For the industry's growth to be the unique equilibrium, protection has to continue even after international competitiveness.