Area Lighting / Emission, optical properties of materials IEV ref 845-04-85 Symbol αn(λ) en Napierian spectral absorption coefficient (of a homogeneous non-diffusing layer) quotient of the Napierian logarithm of the reciprocal of the spectral internal transmittance τi(λ) of a layer of the medium by the length l of the path of a beam of radiation traversing that layer ${a}_{\text{n}}\left(\lambda \right)=-\frac{\text{ln}\text{\hspace{0.17em}}{\tau }_{\text{i}}\left(\lambda \right)}{l}=-\frac{{\text{log}}_{10}{\tau }_{i}\left(\lambda \right)}{l}\text{ln}\text{\hspace{0.17em}}10={A}_{\text{n}}\left(\lambda \right)/l$ [SOURCE: 845-04-84] fr d'absorption spectral népérien (d'un milieu homogène non diffusant) adj quotient du logarithme népérien de l'inverse du facteur de transmission interne spectral τi(λ) d'une couche du milieu par la longueur l du trajet d'un faisceau de rayonnement traversant cette couche ${a}_{\text{n}}\left(\lambda \right)=-\frac{\text{ln}\text{\hspace{0.17em}}{\tau }_{\text{i}}\left(\lambda \right)}{l}=-\frac{{\text{log}}_{10}{\tau }_{i}\left(\lambda \right)}{l}\text{ln}\text{\hspace{0.17em}}10={A}_{\text{n}}\left(\lambda \right)/l$ [SOURCE: 845-04-84] ar معامل الإمتصاص الطيفي النابسري (لطبقة متجانسة غير منتشرة) de spektraler natürlicher Absorptionskoeffizient (einer homogenen, nicht streuenden Schicht), m es coeficiente de absorción espectral neperiano fi spektrinen luonnollinen absorptiokerroin it coefficiente neperiano spettrale di assorbimento (di uno strato omogeneo non diffondente) ko 네이피어 분광 흡수계수, 동질 비확산 층자연대수 분광 흡수계수, 동질 비확산 층 ja 自然対数分光吸収係数, <均質な非拡散層の> no nb napieriansk spektral absorpsjonskoeffisient nn neperisk spektral absorpsjonskoeffisient pl wskaźnik pochłaniania naturalny widmowy (warstwy jednorodnej nierozpraszającej) pt coeficiente de absorção espectral neperiano (de um meio homogéneo não difusor)