In the last part , the differential pas technique , which combines the pas technique with the differential spectrum , overcomes the defect from the two techniques , making it has the both advantage of the pas technique , which is suitable for the measurement of the heavy diffusion > opacity sample , and the advantage of the differential spectrum which is capable of differentiating the overlap spectrum and shoulder peak , is present 第三部分提出導(dǎo)數(shù)光聲光譜技術(shù),將光聲光譜技術(shù)和導(dǎo)數(shù)光譜結(jié)合起來(lái),使導(dǎo)數(shù)光聲光譜技術(shù)同時(shí)具有光聲光譜技術(shù)的可適用于強(qiáng)散射,非透明的樣品測(cè)量和導(dǎo)數(shù)光譜可分辨重疊光譜,分辨肩峰的優(yōu)點(diǎn),又克服各自的缺點(diǎn)。