Satellite records show the minimum Arctic sea ice extents(SIEs) were observed in the Septembers of 2007 and2012, but the spatial distributions of sea ice concen
Millimeter-wave communication has received considerable attention for use in new-generation broadband wireless communication because of the scarcity of microwav
当理查德·奥康纳博士“出于好奇”在实验室里分析中国香烟的成分时,他恐怕想不到会找到一道新配方。这位美国罗斯韦尔帕克癌症学会(Roswell Park Cancer Institute)的研究人员发现,中国13个品牌的香烟中重金属含量是加拿大香烟的2—3倍。 重金属包括砷、镉和铅。它们无一例外是冷血杀手:砷是砒霜的主要成分;镉被归类为“头等致癌物”,可能引发肺纤维化和肾脏病变;铅可能造成顽固的便秘
A fiber-based, star-shaped joint time and frequency dissemination scheme is demonstrated. By working in cooperation with the existing commercial telecommunicati