Dr Hess envisages a ray of light travelling down an optical fibre made from two materials: a core with a negative refractive index and an outer sheath with a positive one.

赫斯博士构想出一个画面，即一道光正穿越于一个由两种材料制作的光导纤维，一种是具有正折射指数的纤维核，另一种则是具有正折射指数的外围。

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Processing the aluminum weld image from the scanning of the X ray negative can derive the binary image of the weld defects.

利用X射线底片扫描成像法得到铝合金焊缝图像，再通过图像处理方法即可得到焊接缺陷二值图象。

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Conclusion There are varied clinical manifestations in pneumothorax patients with thoracic X-ray negative. CT was the best diagnosis way of the disease.

结论胸片阴性的气胸患者，临床表现多种多样，CT是诊断该病的最佳方法。

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Man Ray in the 1920s used solarisation, which gives photographs negative and positive characteristics, a perfect technique for a surrealist.

ECONOMIST: Snapping up the past

In the past week, 18% of the time that Ray Lewis is mentioned on social media, it is a negative reference, and of that negative conversation, approximately half of the mentions reference his involvement in the aforementioned Atlanta nightclub murder.

FORBES: Baltimore Ravens' Ray Lewis Still Questioned In The Court Of Public Opinion