A leap second is added to keep uniform timekeeping within 0 . 9 second of the earth ' s rotational time , which can speed up or slow down because of many factors , including ocean tides 增加这一闰秒是为了保证协调世界时原子时和地球自转时间天文时之间的差距控制在0 . 9秒以内，地球自转速度的加快或减慢受到很多因素的影响，潮汐就是其中之一。
A leap second is added to keep uniform timekeeping within 0 . 9 second of the earth ' s rotational time , which can speed up or slow down because of many factors , including ocean tides 增加这一闰秒是为了保证协调世界时（原子时）和地球自转时间（天文时）之间的差距控制在0 . 9秒以内，地球自转速度的加快或减慢受到很多因素的影响，潮汐就是其中之一。
Besides , by reason of its long distance from jupiter , the earth can maintain a rather circular orbit . also the gravitation of the moon can stabilize the tilt of the rotational axis of the earth , thus restricting climatic fluctuation within a narrow range 另外，地球因与木星保持距离，能维持著一个几近圆形的轨道，加上月球的引力稳定了地球自转轴倾斜的角度
Based on classical dynamical equation on elastic oarth rotation , an associated dynamical equation containing both nutation and wooble of earth rotation has been deduced through introducing motion of nutation frame with respect to inertial spatial frame 基于经典的弹性地球自转动力学理论，通过引入章动参考系相对惯性空间的运动，建立了弹性地球极移和章动的联合动力学方程。
2 ） this paper research mainly the influence of the cluster satellite circumnavigation 、 earth - rotation 、 satellite attitude to the baseline variation and the speed measurement accuracy , and give the correcting mathematical formula and the relative curvature 2 ） 、着重分析分布式卫星sar系统中卫星环绕、地球自转、卫星姿态对基线、测速精度的影响，并绘出了相应的数学模型及关系曲线。
Abstract : this paper analyzes the astronomical backgrounds , such as the positons of celestial objects , variation in the earth rotation and solar activities , etc . , for the recent three moderate and strong earthquakes from chengjiang earthquake to qiubei earthquake in yunnan province 文摘:分析了澄江地震至丘北地震期间云南发生的3次中强震时的天体位置、地球自转与太阳活动等天文背景。
The variation of regional stress field can be genetically interpreted by the rotation speed variation of the earth and its impact on the movement of lithosphere plate and deep processes of the earth , it is also related to the earlier structural feature and boundary of the basin 区域应力场变化可以用地球自转速度变化引起的岩石圈板块活动及触发的深部过程来解释，亦与先期构造形迹和盆地边界条件有关。
Since the elliptical orbits of the moon and the earth and the tilt of the earth s rotation axis also affect the forces exerted by the moon and the sun on the earth , the highest and lowest sea levels associated with spring tide are different from month to month 此外，由于月球运行及地球公转的轨道呈椭圆形，及地球自转轴倾斜的影响，令月球和太阳的引力出现变化，因此，每月的大潮所引致的水位变化亦有所不同。
The north border of the basement , extended from west to east along the north latitude 38 , this latitude structure zone is part of the zone in the middle of ordos basin along the north latitude 38 , this is caused by the rate of earth rotation , according with the condition of global harmonic function 压陷北界沿北纬38带东西向展布，该纬向构造是沿鄂尔多斯盆地中部38带分布的纬向构造带的一部分，是由地球自转速率变化引起，符合全球协和函数的条件。
Jt91 - 200 artillety gyro altazimuth is a fix instument which can research the grid north automatically and determine grid north azimuth at any direction . it works by making use of the physical features of gyro and influences of earth rotation . the equipment of this instument will play a important role in topographic clement Jt91 - 200型炮兵陀螺经纬仪是利用陀螺本身的物理特性和地球自转的影响，实现自动寻找其北方向和测定任一方向线的真北方位角的定向仪器。该型炮兵陀螺经纬仪的装备使用，对我军炮兵测地分队的测地保障发展将产生重大影响。
