Real Surface Radiation 目 Emissivity E(,T) Spectral E(T) emissivity Eō(2，T月 E(T total emissivity E=」E(,T)dM 广cE(,IdM c,Eu(,T)）d几 ￡= OT4 E(T)=OT4 e=1 BlackbodyReal Surface Radiation  Emissivity λ λ λ ε λ λ = ( , ) ( , ) E , T E T b = ε ( ) ( ) E T E T b   ∞ ∞ = = 0 , 0 ( , ) ( ) ( , ) ε λ λ λ λ λ λ λ E T d E T E T d b 4 Eb ( T ) = σT 4 0 , ( , ) T E T d b σ ε λ λ ε  λ λ ∞ = ε = 1 Blackbody total emissivity Spectral emissivity