Kirchhoff's law of thermal radiation rarefied material such as air, or transparent material, through which observations can be made. The interface is not a material body and can neither emit nor absorb. It is a mathematical surface belonging jointly to the two media that touch it. It is the site of refraction of radiation that penetrates it and of reflection of radiation that does not. As such it obeys the Helmholtz reciprocity principle. The opaque body is considered to have a material interior that absorbs all and scatters or transmits none of the radiation that reaches it through refraction at the interface. In this sense
A Moving Sound York City – 2007 Ollin Kan Festival, Mexico City -2007 The Quebec City Festival, Canada -2007 Grassroots Festival, Ithaca NY – 2007 Chicago World Music Festival – 2007 WOMEX, Music Exposition Spain – 2006 MOFFOM Festival, Prague, CZ – 2006 The New York Public Theater – 2006 A Moving Sound A Moving Sound () or Sheng Dong is a Taiwanese music act consisting of vocalist/dancer Mia Hsieh, vocalist, bass guitarist and zhong ruan player Scott Prairie, erhu player I-Fang Chen, and zhong ruan player Chih-Ling Chen. In A Moving Sound’s music traditional Taiwanese music forms are reinterpreted to create new