A vibration period tends to decrease or remain constant as energy is lost, as is the case for a pendulum . 在损失能量时，振动周期倾向于减小或保持不变，如同单摆那样。
A study of motion periods of two nonlinear elastic springs 两类非线性弹簧振动周期的研究
Non - linear circuit vibrate - periodie bifurcation and chaos phenomenon 非线性电路振动周期的分岔与混沌现象
Approximate analytical periods to oscillations of a spherical gas bubble in an ideal incompressible fluid 理想不可压流体中气泡非线性振动周期的解析逼近
So it is the next work to search the variances periodicity and its response to global climate change in order to forecast future 寻找方差的振动周期和对全球气候变化的响应，对未来进行预测，是需要进一步研究的内容。
