Experimental demonstration of guiding and bending of electromagnetic waves in a photonic crystal   总被引：3，自引：0，他引：3  

SY Lin  E Chow  V Hietala  PR Villeneuve  JD Joannopoulos 《Science (New York, N.Y.)》1998,282(5387):274-276

The routing and interconnection of optical signals through narrow channels and around sharp corners are important for large-scale all-optical circuit applications. A recent computational result suggests that photonic crystals may offer a novel way of achieving this goal by providing a mechanism for guiding light that is fundamentally different from traditional index guiding. Waveguiding in a photonic crystal and near 100 percent transmission of electromagnetic waves around sharp 90 degree corners were observed experimentally. Bending radii were made smaller than one wavelength.  相似文献   

Evidence for extreme climatic warmth from late cretaceous arctic vertebrates   总被引：1，自引：0，他引：1  

JA Tarduno  DB Brinkman  PR Renne  RD Cottrell  H Scher  P Castillo 《Science (New York, N.Y.)》1998,282(5397):2241-2244

A Late Cretaceous (92 to 86 million years ago) vertebrate assemblage from the high Canadian Arctic (Axel Heiberg Island) implies that polar climates were warm (mean annual temperature exceeding 14 degreesC) rather than near freezing. The assemblage includes large (2.4 meters long) champsosaurs, which are extinct crocodilelike reptiles. Magmatism at six large igneous provinces at this time suggests that volcanic carbon dioxide emissions helped cause the global warmth.  相似文献