qū / lǜ / xiàng / liàng / miáo / shù / le / qū / xiàn / zài / yì / diǎn / chù / de / wān / qū / fāng / xiàng曲率向量描述了曲线在一点处的弯曲方向。The curvature vector describes the direction in which a curve bends at a point.