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121.
Micropacked columns are constructed using graphitized carbon black as a support for gas-liquid-solid chromatography. Their effectiveness is evaluated in terms of Van Deemter plots, flow-rates, inlet pressure and column capacity. It is shown that such columns, by choosing an appropriate liquid phase, can be used for a wide range of temperatures and types of compound. Analytical applications connected with the analysis of complex organic mixtures in water are discussed. The problems of the analysis of air pollutants are also considered. 相似文献
122.
Gian Fabrizio De Angelis Diego de Falco Francesco Guerra 《Communications in Mathematical Physics》1977,57(3):201-212
Wilson's lattice approximation allows us to apply classical statistical mechanics ideas to the study of Scalar Quantum Electrodynamics. Our main tools are Griffiths-Kelly-Sherman inequalities, the transfer matrix formalism and exponential bounds. Our main result is the existence of the infinite volume limit for every value of the coupling parameters. 相似文献
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Ruggieri F Fanelli M Di Pasquale D Burri E Petitta M Mazzeo P 《Annali di chimica》2005,95(9-10):607-616
In the present work are reported the results of a monitoring on a vast scale, carried out through evaluation of opportune chemical parameters, of the pollution state of the agricultural-industrial settlement of the Fucino Plain. The parameters took into consideration have been the presence of wide consumption pesticides and of ionic species as Cl-, NO2-, NO3-, NH4+, the quantification of the dissolved oxygen, of the temperature, of the conductivity, of pH and eH. Collected data are used for chemometric elaboration. The water systems examined, by means of drawing campaigns carried out at regular intervals in winter, spring, summer, and autumnal seasons, are represented by superficial waters constituting a network of irrigation canals fed by stratum and meteoric waters. In this work are reported the results relative to the drawing campaigns. 相似文献
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In this note we supply an elementary proof of the following well-known theorem of R. Stanley: the -vectors of Gorenstein algebras of codimension 3 are SI-sequences, i.e. are symmetric and the first difference of their first half is an -sequence.
129.
We performed density functional theory calculations of the atomic and electronic structure of a dense monolayer of phenyl-terminated alkyl chains chemisorbed onto the (100) Si surface. Different adsorption sites were characterized for both the pristine and (2 x 1) reconstructed surface. A strong effect on the ordering and alignment of the molecular energy levels with respect to the Fermi level of silicon is observed, consequent to intermolecular screening in the monolayer and of the appearance of surface localized states, as a function of the different bonding arrangements. Some possible consequences of these findings are discussed in the framework of the experimental synthesis of such monolayers as molecular current rectifiers in silicon-integrated nanoscale electronics. 相似文献
130.
Guerrieri F Maccone L Wong FN Shapiro JH Tisa S Zappa F 《Physical review letters》2010,105(16):163602
The Rayleigh diffraction bound sets the minimum separation for two point objects to be distinguishable in a conventional imaging system. We demonstrate sub-Rayleigh resolution by scanning a focused beam--in an arbitrary, object-covering pattern that is unknown to the imager--and using N-photon photodetection implemented with a single-photon avalanche detector array. Experiments show resolution improvement by a factor ~(N-N(max))(?) beyond the Rayleigh bound, where N(max) is the maximum average detected photon number in the image, in good agreement with theory. 相似文献