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921.
Bertram TH Perring AE Wooldridge PJ Crounse JD Kwan AJ Wennberg PO Scheuer E Dibb J Avery M Sachse G Vay SA Crawford JH McNaughton CS Clarke A Pickering KE Fuelberg H Huey G Blake DR Singh HB Hall SR Shetter RE Fried A Heikes BG Cohen RC 《Science (New York, N.Y.)》2007,315(5813):816-820
We present a statistical representation of the aggregate effects of deep convection on the chemistry and dynamics of the upper troposphere (UT) based on direct aircraft observations of the chemical composition of the UT over the eastern United States and Canada during summer. These measurements provide unique observational constraints on the chemistry occurring downwind of convection and the rate at which air in the UT is recycled. These results provide quantitative measures that can be used to evaluate global climate and chemistry models. 相似文献
922.
Wysession ME Langenhorst A Fouch MJ Fischer KM Al-Eqabi GI Shore PJ Clarke TJ 《Science (New York, N.Y.)》1999,284(5411):120-125
Observations of core-diffracted P (Pdiff) and SH (SHdiff) waves recorded by the Missouri-to-Massachusetts (MOMA) seismic array show that the ratio of compressional (P) seismic velocities to horizontal shear (SH) velocities at the base of the mantle changes abruptly from beneath the mid-Pacific (VP/VS = 1.88, also the value predicted by reference Earth models) to beneath Alaska (VP/VS = 1.83). This change signifies a sudden lateral variation in material properties that may have a mineralogical or textural origin. A textural change could be a result of shear stresses induced during the arrival at the core of ancient lithosphere from the northern Pacific paleotrench. 相似文献
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Two switchable, mesoscopically periodic materials were created by combining crystalline colloidal array (CCA) self-assembly with the temperature-induced volume phase transition of poly(N-isopropylacrylamide) (PNIPAM). Body-centered-cubic CCAs of hydrated, swollen PNIPAM particles Bragg-diffract infrared, visible, and ultraviolet light weakly, whereas arrays of compact shrunken particles diffract efficiently. A tunable diffracting array was also created by embedding a CCA of polystyrene spheres within a PNIPAM hydrogel that swells and contracts with temperature; thus the array lattice constant varies with temperature, and the diffracted wavelength was thermally tunable across the entire visible spectrum. These materials may find applications in many areas of optics and materials science. 相似文献
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Joyce A. Clarke Gurdip S. Brar J. Procopiou 《Plant foods for human nutrition (Dordrecht, Netherlands)》1976,25(3-4):219-225
The fatty acid, carbohydrate and amino acid composition of dried pistachio kernels was determined. On a dry weight basis they contained about 55% oil. The unsaturated fatty acids oleic and linoleic constituted about 80% of this oil. Carbohydrate analysis of a hydrolysed sample showed the predominant sugar to be glucose followed by galactose and mannose with traces of fucose, arabinose and xylose. The total amino acid content was about 25% by weight. Nine essential amino acids were present with only cystine in a limiting amount and with a high level of lysine. 相似文献