It has shown that less 1, 2-unit content corresponds to lower potential barrier of internal rotation and hence to lower energy of rotational isomerization.

进一步的研究表明，低1，2-链节含量对应着较低的分子链内旋转势垒和内旋转异构化能。

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Turret punching unit with four-mode vertical position, the whole barrier-free turntable, good view, use without the frequent replacement of mold, improve work efficiency.

冲孔单元采用立式转塔四模位，无障碍整体转盘，视线好，使用时不用频繁的更换模具，提高了工作效率。

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We observed the structural change of nerve unit and blood-brain barrier by the electron microscope.

观察具有最佳镇静催眠作用的酸枣仁汤对大鼠神经元及血脑屏障超微结构的影响；

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The back four defended well as a unit, operating close together, covering each other and forming a barrier which was rarely pierced.

BBC: Battle of the continents