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The photoyellowing progress of silk fibroin and its influence factors under ultraviolet irradiation have been studied, which was conducted by combining different ultraviolet wavelengths, different ultraviolet irradiancies, and different irradiation times. The blue-ray whiteness after ultraviolet irradiation was tested to characterize the course of photoyellowing of silk fibroin. The result shows that the photoyellowing degree of silk fibroin varies significantly under ultraviolet irradiation of different wavelengths and with the increasing in ultraviolet irradiancy at 313-nm wavelength, the photoyellowing degree aggravates correspondingly, while the ultraviolet irradiancy at 340-nm wavelength has little obvious impact. Additionally, the photoyellowing degree of silk fibroin is positively correlated to ultraviolet irradiancy and irradiation time. To quantitatively analyze the alteration of tyrosine content during the photoyellowing of the silk fibroin, l-tyrosine standard curve Y = 8.14666X − 0.88951 was e...

With the gradually increasing in the cognition of the light biological effects, the technological progress of LED is constantly meeting people's pursuit of light quality, but the technical indexes proposed in luminosity, chroma, light quality evaluation and standard of the traditional lighting theory are different from people's subjective visual effect. Furthermore, people's favorite chromaticity coordinates of light source are not in the Planck blackbody radiation curve. More and more experimental results show that the traditional lighting theory is in urgent need of innovation. Starting from human's following the natural law and rulet, the paper probes into the mechanism of action of light on human body (eyes, physiology and psychology) and analyzes the impact of different spectral intensity and combination on human endocrine hormone in different time based on light regulation of human biological rhythm. It conducts organic combination of illumination and the changes of human endocrine biological parameters to detect human “photo-biomarkers” through qualitative and quantitative analysis and gradually sheds light's regulation on human health, and then put forwards the definition, localization and further development of health lighting.