indemonstrable

Based on conventional discrete element method, the idea and calculating method of dynamic discrete element (DDEM) is proposed in the paper and a relevant program is deve.

在常规离散无法的基础上提出了动力离散元法的思想及计算方法，并编制了计算程序ＤＤＥＭ，最后给出了该方法在岩体动力学中的应用实例。

The flangeless and threadless valves and fittings developed by a German company -HAWLE are widely used in European countries now.

德国HAWLE公司开发的无法兰、无螺纹的闸门和管道配件,目前在欧洲各国饮用水管道中逐步推广应用,其连接方式称为BAIO-SYSTEM(卡口式连接系统),其优点是安装简单,具有抗拉锁定接口,重量轻,储备费用低,可广泛适用于铸铁、钢、PE和PVC管,代表了未来管道附件的发展趋势。