A novel method based on time-resolved spectra of multiple scattering has been developed to distinguish between skim milk and whole milk. Three-dimensional fluorescence spectra of milk show that the main fluorescence is located around 350 nm, and there is nearly no fluorescence when excited at the wavelengths longer than 500 nm. However, when excited at 500 nm or longer, the time-resolved spectra of milk are wavelength-dependent and have a long lifetime process signal when detected at long wavelengths. The power experiments exclude the possibility that the long lifetime process is caused by the excitation power, and the SiO₂ experiments suggest that the process is attributed to the multiple scattering in milk. The average lifetimes extracted from the time-resolved spectra at 680 nm have a great difference between skim milk and whole milk, which indicates that the fat globules prefer to trap the photons around 680 nm. The experiments between brands were also designed, and the results prove the reliability of the distinguishing method. Although more mechanism details require further exploring, the method has already shown a great potential for applications.

中文翻译：

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利用多次散射的时间分辨光谱快速区分脱脂牛奶和全脂牛奶

已开发出一种基于时间分辨多重散射光谱的新方法，以区分脱脂牛奶和全脂牛奶。牛奶的三维荧光光谱显示，主荧光位于350 nm左右，而在大于500 nm的波长处激发时几乎没有荧光。但是，当以500 nm或更长的波长激发时，牛奶的时间分辨光谱与波长相关，并且在长波长下检测时具有较长的寿命过程信号。功率实验排除了长寿命过程是由激发功率和SiO ₂引起的可能性实验表明，这一过程归因于牛奶中的多重散射。从脱脂牛奶和全脂牛奶在680 nm的时间分辨光谱中提取的平均寿命存在很大差异，这表明脂肪小球更喜欢将光子捕获在680 nm左右。还设计了品牌之间的实验，结果证明了该识别方法的可靠性。尽管更多的机制细节需要进一步探索，但是该方法已经显示出巨大的应用潜力。