In reply to Axil Axil's message of Wed, 28 May 2014 22:16:29 -0400: Hi, >"Heat based technologies have the added requirement to maximize temperature >rise, which implies minimizing radiation in the thermal infrared band. Thus >there are conflicting requirements of strong absorption in the visible, >with minimum emission in the far infrared range; the figure of merit >for this is termed selectivity. " > >The requirement called for here is for minimum emission in the far infrared >range. Minimum emission means refection.
Actually the called for requirement is for maximum absorption in the visible range *combined* with minimal emission in the far infrared. http://arxiv.org/ftp/arxiv/papers/1202/1202.6603.pdf appears to concentrate primarily on the properties in the visible range. I don't see any mention of the properties of Nickel in the far infrared. Perhaps you could point it out? > > >Nickel meets the requirement because it has minimum emission in the far >infrared range. > >"This paper has studied absorption in ultra-thin layers of nickel, gold and >silver. It is shown that nickel possesses optical properties that make it >ideal for use in solar thermal and solar thermionic applications and that >there is an optimum thickness for maximising absorption across the solar ^^^^^^^^^^ >spectrum of ~10-13nm." [snip] Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
