fractions形态fractionn.小部分；少许；分数；片段fractions of carbohydrate碳水化合物组分fraction frequency offset小数倍频率偏移fractionated radiotherapy分次(割)放射治疗fractionated preciptation分级沉淀fraction of less polarity弱极性馏分Fraction Fourier transform分数傅里叶变换Fraction out of pore space含量fractionated precipitation分级沉淀fraction function sequence分式函数列Fractionation distribution形态分布