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81.
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
82.
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
83.
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85.
Rendiconti del Circolo Matematico di Palermo Series 1 - 相似文献
86.
87.
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
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89.
Pietro Lura Frank Winnefeld Stefanie Klemm 《Journal of Thermal Analysis and Calorimetry》2010,101(3):925-932
Isothermal calorimetry and chemical shrinkage measurements are two independent techniques used to study the development of
hydration in cementitious systems. In this study, calorimetry and chemical shrinkage measurements were combined and simultaneously
performed on hydrating cement paste samples. Portland cement pastes with different water to cement ratios and a cement paste
containing calcium sulfoaluminate clinker and anhydrite were studied. The combined calorimetry/chemical shrinkage test showed
good reproducibility and revealed the different hydration behavior of sealed samples and open samples, i.e., samples exposed
to external water during hydration. Large differences between sealed and open samples were observed in a Portland cement paste
with low water to cement ratio and in the calcium sulfoaluminate paste; these effects are attributed to self-desiccation of
the sealed pastes. Once the setup is fully automatized, it is expected that combined calorimetry/chemical shrinkage measurements
can be routinely used for investigating cement hydration. 相似文献
90.