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91.
Pietro Pellogio 《Fresenius' Journal of Analytical Chemistry》1867,6(1):396-398
Ohne ZusammenfassungVon dem Verf. in französischer Sprache mitgetheilt. 相似文献
92.
Characterization of a Marshall-Olkin type class of distributions 总被引:1,自引:0,他引:1
Pietro Muliere Marco Scarsini 《Annals of the Institute of Statistical Mathematics》1987,39(1):429-441
Summary A class of bivariate distributions that generalize Marshall-Olkin's one is characterized through a functional equation which
involves two associative operations. The obtained distributions concentrate positive mass on the linex=y when the two associative operations coincide; otherwise a positive mass is concentrated on a continuous monotone function.
Work performed while the authors were members of CNR-GNAFA. 相似文献
93.
Pietro Burgatti 《Annali di Matematica Pura ed Applicata》1931,9(1):121-142
Sunto Si studiano le varietà a due dimensioni immerse in unS
4
euclideo. Definite certe due normali principali, si esaminano le proprietà delle superficie nell'intorno di un punto, le
curvature, e le sue linee più caratteristiche. Infine si dà sotto forma esplicita ed espressiva un gruppo di formule fondamentali
relative all'impiego delle tre forme differenziali quadratiche atte a definire la varietà considerata. 相似文献
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High-dielectric constant oxides are the focus of intense current research. As a contribution to the rationalization of the search for candidate materials, we compare the dielectric properties obtained from first-principles linear-response calculations for two phases—the ground state bixbyite and the competing hexagonal structures—of the crystalline oxide Lu2O3. The dielectric constants of bixbyite is about 12 and that of hexagonal is about 19 (the electronic constant being about 4.5 in both cases). This difference is due almost exclusively to the vibrational properties, with minor or no influence of charge anomaly differences; as these are related mainly to oxygen vibrations, we argue that the dielectric properties of sesquioxides will be determined mostly by their preferred structure, i.e. they will be poorer for bixbyite (e.g. Y2O3) than for hexagonal (e.g. La2O3) sesquioxides. 相似文献
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97.
Rendiconti del Circolo Matematico di Palermo Series 1 - 相似文献
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99.
Loris Tonidandel Eugenio Ragazzi Pietro Traldi 《Rapid communications in mass spectrometry : RCM》2009,23(3):403-408
Baltic amber contains high levels of succinic acid, most of which is part of the polymer framework, and only recently has the presence of microcrystals of free succinic acid been documented by scanning electron microscopy and X‐ray diffraction analysis. The determination of succinic acid can be used for an easy identification of Baltic amber among other fossil resins and to distinguish it from imitations, widely diffused on the market, produced with natural or modified recent or sub‐fossil resins, such as copals. We report here a simple method, based on negative ion electrospray ionization mass spectrometry, for evaluating the free succinic acid content in water/methanol extracts of ambers from different origin, using a sample of about 20 mg. The limit of quantification is better than 1 ppm and, when applied to a set of amber samples of different origin, it was able to distinguish those of Baltic origin (showing free succinic acid levels in the range 50–400 ppm) from the others (for which succinic acid was undetectable, i.e. at levels lower than 1 ppm). Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
100.