昴星团(离地球)大约有440 光年 远,而毕星团则大约是此距离的 三分之一: 150 光年. Pleiades are approximately 440 light - years away and the Hyades are about one - third that distance: 150 light - years .
中心力是由球对称的势能函数而来的力.A central force is one derived from a potential - energy function that is spherically symmetric.有心力是一种径向力,它的大小只取于离原点的距离.A central force is a radial force which depends only on the distance from the orig...
The utility model relates to a new honeycomb briquet moulding machine.本实用新型是一种新型的蜂窝煤成型机.a cell of a honeycomb蜂房But now the honeycomb board manufacturers often control bad quality problems often.但现在蜂窝纸板生产厂家往往因控制不好经常出现质量问题...