An overview of the research conducted in the area of linear and nonlinear vibrations in the turning-point frequency range of loudspeakers and revolution shells is given in chapter 1.

第1章回顾了扬声器和旋转薄壳在转点频段的线性和非线性振动，发现旋转薄壳转点问题中尚有若干问题有待进一步研究。

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Once mounted, the closer focusing range is attained by turning the lens to it's closest normal focusing point.

一旦装上它后，只要将镜头转到普通的最近对焦距离处，就可获得更近的对焦。

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Cipriani went well wide with a long-range penalty attempt, but the resulting 22m drop-out proved a turning-point.

BBC: Wasps 35-29 Northampton