stem bar

Position the valve stem threads are divided into clear and dark bar bar gate valve two.

按阀杆的螺纹位置划分,可分为明杆闸阀和暗杆闸阀两种.

Do not tighten packing nut enough to bind stem. restrained torsion of thin walled bar

不要过紧旋转填料螺母，以免粘接阀杆。薄壁杆件的约束扭转

This paper focuses on the optimization design of curved stem cranking bar mechanism used single variation parameter ( auxiliary angle) based on the optimum drive angle and maximum itinerary velocity variation coefficient. The method is practical, feasible and can help improve the quality of mechanism design.

利用单变参数（辅助角）按最佳传动角及最大行程速度变化系数对曲柄摇杆机构进行优化设计，提高了机构设计质量，方法实用可行。

The white ruling classes in South Africa try to stem the tide against the color bar, but their efforts are doomed to failure.

南非的白人统治集团企图阻止反对种族歧视的浪潮，但是他们的努力是注定要失败的。