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CNY ¥ 20 |
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Scientific research shows that natural light is a mixture of red, yellow and blue light. Blue light is considered relatively dangerous because of their short wavelength, relatively high energy and penetrating power. But not all blue light is dangerous. Only blue light wi... |
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CNY ¥ 20 |
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Scientific research shows that natural light is a mixture of red, yellow and blue light. Blue light is considered relatively dangerous because of their short wavelength, relatively high energy and penetrating power. But not all blue light is dangerous. Only blue light wi... |
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