Keywords: geometric nonlinearity, sag effect, equivalent modulus of elasticity, vehicle - bridge interaction.关键词: 几何非线性 、 中垂效应 、 等效弹性系数 、 车桥互制.The eigenfrequency of oscillation cavity is the function of cavity's geo...
一只鸽子从塔里钻出来，扑扑地拍打着翅膀。A pigeon emerges, wings flapping noisily, from the tower.耗时五年才钻到了基岩。It took five years to drill down to bedrock.窗户对他来说实在太小，他钻不过去。The window was far too small for him to get through....