Term 术语 Definition 定义
velocity
速度
A vector quantity equal to SPEED in a given direction.
在给定方向上,等于速率的矢量。
velocity of sound
声速
See SOUND VELOCITY.
声能通过媒质传送的运动速率。海水中声速受影响的因素是:温度、盐度以及随深度变化而改变的压力。这些因素中任一因素的增强都会引起速度的增加。
veneer
薄层,表层
A thin LAYER of SEDIMENT covering a rocky surface.
覆盖在岩石表面的一种薄沉淀层。
vent
火山孔道
The orifice through which molten LAVA reaches the CRATER of a volcano. Eventually it may become choked as the LAVA solidifies to form a plug... more
The orifice through which molten LAVA reaches the CRATER of a volcano. Eventually it may become choked as the LAVA solidifies to form a plug or neck.
熔岩到达火山出口所经通道。最终可能会由于熔岩固化形成岩颈而堵塞。
Venturi tube
文丘里管
The trade name for a short tube of smal­ler diameter in the middle than at the ends. When a fluid flows through such a tube, the pressure de... more
The trade name for a short tube of smal­ler diameter in the middle than at the ends. When a fluid flows through such a tube, the pressure decr­eases as the diameter becomes smaller, the amount of the decrease being proportional to the SPEED of FLOW and the amount of restriction.
指一种中间比两端直径小的短管。当流体流经该管随着直径变小压力也减小,减少量与流速和流量成比例。
vernal equinox
春分点
See EQUINOX.
黄道与天球赤道的两交点之一。也就是太阳赤纬为零时所在的位置点。每年3月21日前后,太阳的赤纬由南转为北时所在的那一点称为春分点;每年9月23日前后,太阳的赤纬由北转为南时所在的那一点称为秋分点。亦称equinoctial point(二分点)。
vernier
游标
A short, auxiliary SCALE situated alongside the graduated SCALE of an instrument, by means of which fractional parts of the smallest divisio... more
A short, auxiliary SCALE situated alongside the graduated SCALE of an instrument, by means of which fractional parts of the smallest division of the prima­ry SCALE can be measured accurately.
位于仪器刻度尺旁的辅助短尺,利用它可以将基本尺的最小刻度划之小数部分精确地测定出来。
vertex
顶点
(pl. vertices). The highest point; the vertices of a GREAT CIRCLE are the points nearest the POLE. See APEX.
最高点;大圆的顶点是离极最近的点。
vertical
垂线,垂面
(adj.). In the DIRECTION OF GRAVITY; perpendicular to the plane of the HORIZON.
重力的力线方向。如垂线,垂面等。
vertical
垂线,垂面
(n.). The direction in which the force of GRAVITY acts. A vertical line, plane, etc.
重力的力线方向。如垂线,垂面等。
vertical axis
竖轴,纵轴
See AXIS.
在经纬仪或子午仪中通过仪器中心的线,仪器的照准部绕该线旋转。
vertical circle
垂直度盘,垂直圈,地平经圈
See CIRCLE.
天球上过天顶和天顶的大圈。它垂直于真地平。
vertical clearance
垂直间隙,竖向净空
The minimum vertical space availa­ble for passage.
可通过的最小垂直空隙。
vertical collimator
垂直准直仪,垂准器
See COLLIMATOR.
一种用特殊形式安装的望远镜,它能使其视准轴与垂直线(铅垂线方向)重合。能利用它直接在仪器下设置地面标志或直接在地面标志上使仪器对中。
vertical control
高程控制
See CONTROL.
相对于基准面建立的高程控制。
vertical control datum
高程控制基准
See DATUM.
作为高程起算面的基准面(例如:平均海水面)。亦称datum level、reference level、reference plane、levelling datum、datum for heights 。亦可参见datum plane(基准面)。
vertical deflection
垂线偏差
See DEFLECTION OF THE VERTICAL.
地球(大地水准面)上一点的垂线(沿垂线方向)与在参考椭球面上对应点的法线方向之间的夹角,亦称 deflection of the plumb line、deviation of the vertical、station error。
vertical dilution of precision
高程误差放大因子
See DILUTION OF PRECI­SION.
一种表示定位系统所提供的位置(或未知的辅助位置)精度与由系统直接测得的“观测量”的精度之间的关系参数。DOP是几何图形影响定位精度的一种量度。DOP通常与一些术语连用,如几何的、平面的、高程的等。这表明DOP与所有的未知量或某些未知量有关。
vertical intensity of the earth's magnetic field
地磁场垂直强度
The strength of the vertical component of the EARTH's MAGNETIC FIELD.
地磁场垂直分量的强度。
vertical light(s)
直列灯
See LIGHT.
两个以上灯作垂直排列(或水平,或呈几何图形)给出不同灯质或显示。