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-sound success in brief time. Lead Vocalist : Temuulen .TS (Ц. Тэмvvлэн) Born : 1983 29th Oct., 33 years old Has a bachelor's degree from Health Science University In Mongolia, Pianist : Purevsukh .T (Т. Пvрэвсvх) Finished Mongolian University Of Art & Culture, Bassist : Munkhbold .N (Н. Мөнхболд), Drummer :Batpurev (Батпvрэв), Lead Guitarist : Altangerel (Алтангэрэл) They chose "A-sound " as a name, as the meaning the best sound. Everything in A is the best, even at the school A mark is the highest point, that's why they preferred letter " A ", and "Sound". " A-Sound " ( The