Soft Volleyball in the Application of the Teaching of Passing the Ball Face(BF) to Face; Services include the backhand topspin and backspin serves, the forehand topspin and backspin serves, and the high toss service. 软式排球在正面上手传球教学中的应用发球方法包括,反手上旋球和下旋球,正手上旋球和下旋球。和高抛发球。
On methods of training feelings of face spike of volleyball; Washers with ball face 排球正面扣球技术教学的球感练习法GB/T849-1988球面(BF)垫圈
Influences on Ball Face(BF) NC Machining Accuracy of Transmission Clearance 传动间隙对球面(BF)数控加工精度的影响
This paper introduced a green process method of miniature electrical machinery axle, which breaked through the traditional process method : it changes the turning both ends half a ball face for cold-heading, and becomes the outer circle to grinding to cold-drawing. 介绍了一种微型电机轴的绿色加工方法,它突破了微型电机轴传统的加工方法,改车削两端半球面(BF)为冷镦,变外圆磨削为冷拉。
Introducing the structural characteristics of ball face sealing of disc in sealing effect, manufacturing process and material selection, and pointing out several improved sealing structures of ball face. 介绍了截止阀阀瓣球面(BF)密封在密封效果、制造工艺和材料选用方面较锥面和平面结构的特点。给出了改进后的几种球面(BF)密封结构。