然后，进一步研究不同时间尺度下上证国债指数的波动性。
The volatility of SSE T-Bond Index is also researched on various time scales in this paper .
上证国债指数存在一个易变性变动的平均周期，约为20天。
An average cycle which is about 20 days was discovered in the time series of SSE T-Bond Index .
上证国债指数