The body gets most of its vitamin D not from diet but from skin exposed to the ultraviolet B radiation in sunlight.
身体获取的大部分维他命D不是从饮食而是靠皮肤曝露在阳光中的紫外线B射线取得的。
As skin pigmentation increases, so does the period of exposure to ultraviolet B radiation from sunlight needed to synthesise adequate amounts of vitamin d.
当皮肤色素沉着增多，所以需要暴露于阳光下紫外线B辐射的足够时间以合成足够数量的维生素d。
The estimated ultraviolet radiation attenuation coefficient and DOC concentration all existed markedly positive relationship; but UV-B wave band was higher than UV-A wave band.
估算得到的紫外辐射衰减系数与DOC浓度均存在显著性正相关，但UV - B波段要高于UV - A波段。
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