spherical indicatrix of binormal to a curve

例句：

1. 1. The planet Mercury is known for its spherical shape.
   水星以其球形而闻名。
2. 2. The sphere of influence of a company is the area within which it has influence.
   公司的势力范围是其有影响力的区域。
3. 3. The spherical indicatrix of binormal to a curve is the ratio of the lengths of the vectors formed by the binormal and the tangent at the curve's vertex.
   曲线上二向异性的球面指示子是二正弦和切线在曲线顶点处形成的向量长度之比。