Painted on yellow cotton cloth,this Tibetan calendar chart of the Qing Dynasty shows the calculation process of the traditional Tibetan calendar.According to the record,Xizang had the calendar as early as 1,000 years ...Painted on yellow cotton cloth,this Tibetan calendar chart of the Qing Dynasty shows the calculation process of the traditional Tibetan calendar.According to the record,Xizang had the calendar as early as 1,000 years BC.At that time,the month was calculated with the change of the moon.In the 7th century AD,Princess Wencheng entered Xizang and brought the calendar of the Central Plains to Xizang.After that,the Time-wheel calendar of India was also introduced to the Qinghai-Tibet Plateau.展开更多
激光时间传递技术是通过激光脉冲在空间的传播来实现地面与卫星时钟或地球上远距离两地时钟的同步,它具有很高的准确度和稳定度。一些国家已经成功进行了激光时间传递的试验,结果证明利用激光进行时钟之间的同步是有效可行的。介绍国内...激光时间传递技术是通过激光脉冲在空间的传播来实现地面与卫星时钟或地球上远距离两地时钟的同步,它具有很高的准确度和稳定度。一些国家已经成功进行了激光时间传递的试验,结果证明利用激光进行时钟之间的同步是有效可行的。介绍国内外已有的激光时间传递试验的情况和结果,重点介绍美国地面与机载原子钟之间的激光时间比对,以及法国的LASSO(LAser Syn-chronization from Stationary Orbit)和T2L2(Time Transfer by Laser Link)计划。展开更多
文摘Painted on yellow cotton cloth,this Tibetan calendar chart of the Qing Dynasty shows the calculation process of the traditional Tibetan calendar.According to the record,Xizang had the calendar as early as 1,000 years BC.At that time,the month was calculated with the change of the moon.In the 7th century AD,Princess Wencheng entered Xizang and brought the calendar of the Central Plains to Xizang.After that,the Time-wheel calendar of India was also introduced to the Qinghai-Tibet Plateau.
文摘激光时间传递技术是通过激光脉冲在空间的传播来实现地面与卫星时钟或地球上远距离两地时钟的同步,它具有很高的准确度和稳定度。一些国家已经成功进行了激光时间传递的试验,结果证明利用激光进行时钟之间的同步是有效可行的。介绍国内外已有的激光时间传递试验的情况和结果,重点介绍美国地面与机载原子钟之间的激光时间比对,以及法国的LASSO(LAser Syn-chronization from Stationary Orbit)和T2L2(Time Transfer by Laser Link)计划。
