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github：https://github.com/MichaelBeechan
CSDN：https://blog.csdn.net/u011344545
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1. Year, month, day, hour, minute, second, turn to second within a cycle
2. Convert seconds in week to year, month, day, hour, minute and second
3. MJD converts year, month, day, hour, minute and second
4. Convert year, month, day, hour, minute and second to MJD
5. Other conversions