Period characteristics of radiated noise at high frequency is investigated by a method based on short time Fast Fourier Transformation, and propeller speed is estimated.

用短时傅立叶分析的方法研究了辐射噪声在高频段时频变化的周期性，估计了目标的螺旋桨转速。

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Adding course sites slowly with a goal of reaching the estimated number of course sites over a period of time is usually a good approach.

经过一段时间等到上课场所达到预期目标时再行增加乃不失为一项好方法。

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It is estimated that if the semantic search engine to achieve in a very short period of time scanning the entire network, is likely to take several years.

据估计，如果语义搜索引擎要实现在很短的时间内扫描整个网络，很有可能还要花费数年的时间。

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The new images -- taken over several years -- reveal the channels which were carved out by flooding over an estimated 500 million year period -- a time when Mars was thought to be cold and arid.

ENGADGET: Alt-week 3.9.13: Sunstones, knotted vortices and a zero-g robot

On Jan. 18 Nortel was trading at 58 times 2001 estimated earnings, while Lucent's multiple was 25 for the same time period.

FORBES: Time to buy Lucent