To simplified the designing, diagram presentation, construction and profile of helicoidal stair, the formation of helicoid is analyzed, and it's mathematical model is studied.

为简化旋转楼梯的设计、图示、施工及剖面形状，对螺旋面的形成进行了分析，建立了螺旋面的数学模型。

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The utility model discloses a rechargeable lamp, including a cylindrical lamp holder, a helicoidal socket, a holder motherboard, a conduction metal sheet and a storage battery.

本实用新型公开了一种能充电的电灯，由圆筒灯座、螺圈灯口、灯座底板、导电金属片和蓄电池组成。

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