Open cell aluminum foams were prepared by traditional powder metallurgy process, with spherical carbamide particles as the space-holder.

以球形尿素颗粒为造孔剂，采用传统的粉末冶金工艺制备开孔泡沫铝并研究了其性能。

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Open cell aluminum foams were prepared by traditional powder metallurgy process, with spherical carbamide particles as the space-holder. The properties of open cell aluminum foams were studied.

以球形尿素颗粒为造孔剂，采用传统的粉末冶金工艺制备开孔泡沫铝并研究了其性能。

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American astronaut Jeff Williams became the U. s. record-holder for most time spent in orbit after this mission brought him up to 534 days spent in space across four separate missions.

美国宇航员杰夫·威廉姆斯成了美国在轨道内最长时间纪录的保持者——算上这次任务，他一共参加了四次不同的任务，在太空中待了534天。

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The current Chair-holder of the UNESCO Chair in Astronomy, Astrophysics and Space Sciences, Dr Suleiman Baraka, is a well-known scientist with an international profile.

UNESCO: NATURAL SCIENCES