The studying results show that the classical elastic wave equation of spherical wave is only true for fixed amplitude phase and described only kinematic equation of phase velocity.

研究揭示经典的球面波波动方程只对固定振幅相成立，即只描述了相的运动方程，其波速为相速度。

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To deal with filter value calculation instability, people put forward and carry out lots of methods in practice such as self-adaptive filter, fixed amplitude filter and square root filter, etc.

为了解决滤波器数值计算不稳定问题，实践中提出并应用了许多方法，如自适应滤波、固定增益滤波、平方根滤波等。

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For fixed damping and fixed excited frequency the motion of the beam under small amplitude of force is periodic, but becomes chaotic through period doubling bifurcation with increase of the force.

对固定的参数激励频率和阻尼，当参数激励幅值较小时梁的运动是周期的，但大幅值激励会使运动通过倍周期分岔变为混沌。

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