Chinese English

A point that is the start or end point of a line segment. In ASTRONOMY, one of the two points of intersection of the ORBIT of a PLANET, PLANETOID, or COMET with the ECLIPTIC, or of the ORBIT of a SATELLITE with the plane of the orbit of its primary. That point at which the body crosses to the north side of the reference plane is called the ascending node; the other, the descending node. The line connecting the nodes is called LINE OF NODES. Also called NODAL POINT. See REGRESSION OF THE NODES. In OCEANOGRAPHY, that part of a STANDING WAVE where the vertical motion is least and the horizontal VELOCITIES are greatest. See PARTIAL NODE. In optics, a NODAL POINT.

1. 指线段的起点或终点。 2. 在天文学中，指行星、小行星或慧星的轨道与黄道的两个交点之一，或卫星轨道与其主星轨道平面的两个交点之一。天体经过参考面北边时的点为升交点，另一个为降交点。两点连线被称为交点线。亦称Nodal point（交点）。参见regression of the nodes（交点退行）。 3. 在海洋学中，指垂直运动最小而水平速度最大的那部分驻波。参见partial node（不全节）。 4. 在光学中，指节点。 5. 在ECDIS中，指由一组坐标定位的零维空间对象。节点可以是孤立的或连接的。

月球相继两次通过其运行轨道上同一交点所经历的时间。交点月平均长为27.21222个平太阳日。亦称dracontic month（交点月）。

In OCEANOGRAPHY, concretionary lumps of manga­nese, cobalt, iron, and nickel found widely scattered on the ocean floor. ROCKS of various sizes and shapes often are encrusted with these metals.

在海洋学中，指广泛分散在海底的锰、钴、铁和镍的结核块。不同大小和形状的岩石常具有这些金属的外壳。

Any undesired SOUND. By extension, noise is any unwanted disturbance within a useful FREQUENCY BAND, such as undesired electric WAVES in a transmission channel or device.

A DIAGRAM showing, to SCALE, the relationship between several variables in such manner that the value of one which corresponds to known values of the others can be determined graphi­cally. See CONVERSION SCALE, CONVERSION TABLE.

表示或衡量几个变量之间的关系的图表，可用其确定对应于已知变量值的某一未知变量值。参见conversion scale（换算比例）和conversion table（换算表）。

Tidal or tidal current const­ants such as LUNITIDAL INTERVALS, ranges, and inequalities, which can be derived directly from OBSERVATION without regard to the HARMONIC CONSTITUENTS.

In TIDE PREDICTION, an approximate method based on the principle that 'the TIDE follows the MOON'. It makes use of the close relationship that exists between the TIME of TIDE at most places and the MOON's MERIDIAN TRANSIT.

在潮汐预报中，指一种利用多数地区的潮时与月亮中天的紧密关系，以“月亮引潮”原理为基础的近似方法。

In general, a straight line perpendicular to a surface or to another line. In GEODESY, a straight line perpendicular to the surface of the SPHEROID.

由观测方程、条件方程或相关方程导出的一组联立方程中的某一方程。在最小二乘法平差中，用法方程解得的值（直接求解或通过相关方程求解）代入观测方程或条件方程中以求得所需的改正值。

A standard SEA WATER preparation, the CHLORINITY of which lies between 19.30 and 19.50 per mille (0/00) and has been determined to within ± 0.001 per mille. Normal water is used as a convenient comparison standard for chlorin­ity measurements of sea water samples by TITRATION. It is prepared by the Hydrographi­cal Laboratories, Copenhagen, Denmark. Also called standard sea water.

由丹麦哥本哈根海道测量实验室配置的标准海水，其氯度为19.30～19.50‰，测定精度在±0.001‰以内。标准海水被用作滴定法测量海水水样氯度的简便比较标准。亦称为standard sea water（标准海水）。

An arbitrary REFERENCE DIRECTION used with GRID NAVIGATION. The northerly or zero direction indicated by the grid datum of directional reference.