This is a multi-barrel heavy machine gun on an anti-aircraft mount.

图中为设置在高射机枪架的多管重机枪。

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Mathematical model of multi-layer composite artillery barrel with ceramic liner was built by using axisymmetric elastic theory, and stress computer program of the composite barrel was developed.

应用轴对称弹性理论建立了陶瓷内衬多层复合身管的数学模型，编写了其应力计算程序。

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Considering the elastic deformation of the barrel, the AA gun is simplified into a multi-rigid body dynamic model.

同时考虑身管弹性变形，建立了火炮发射时的多刚体动力学模型。

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Evidence we have seen suggests that Syrian government forces delivered the 122mm cluster munition rockets containing submunitions using a BM-21 Grad multi-barrel rocket launcher, a truck-mounted system capable of firing 40 rockets nearly simultaneously with a range of 4 to 40 kilometers (2.5 to 25 miles).

CNN: The gruesome toll of deadly cluster bombs in Syria