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121.
Davide Baccherini 《Discrete Mathematics》2008,308(18):4165-4176
We study some combinatorial properties of Tetris-like games by using Schützenberger methodology and probability generating functions. We prove that every Tetris-like game is equivalent to a finite state automaton and propose a straight foward algorithm to transform a Tetris-like game into its corresponding automaton. In this way, we can study the average number of pieces inserted during a game and the average score as a function of the player's ability and the pieces extrusion. 相似文献
122.
In this paper, using the exit-time statistic, we study the structure of the price variations for the high-frequency data set of the bid–ask Deutschemark/US dollar exchange rate quotes registered by the inter-bank Reuters network over the period October 1, 1992 to September 30, 1993. Having rejected random-walk models for the returns, we propose a Markovian model which reproduce the available information of the financial series. Besides the usual correlation analysis we have verified the validity of this model by means of other tools all inspired by information theory. These techniques are not only severe tests of the approximation but also evidence of some aspects of the data series which have a clear financial relevance. 相似文献
123.
Pietro Franceschi Roland Thissen Odile Dutuit Christian Alcaraz Heloise Soldi-Lose Davide Bassi Daniela Ascenzi Paolo Tosi Jan Zabka Zdenek Herman Marcello Coreno Monica de Simone 《International journal of mass spectrometry》2009,280(1-3):119
The long-lived excited states of doubly charged rare gases can markedly affect their reactivity. In this paper we demonstrate the presence of strong state-specific effects in the charge exchange of Ar2+ (3P, 1D and 1S) with several neutral targets (He, Ne, Kr, Xe, D2, and CH4). State sensitive measurements have been performed by producing the different Ar2+ electronic states via tunable synchrotron radiation (Elettra-Trieste, Italy and SuperACO-Orsay, France). From the product ion yield data of charge transfer, state-selected total cross-sections have been deduced. Using the state-specific reactivity of Ar2+ towards different neutral targets, it has been possible to extract the photon-energy-dependent production branching of the three doubly charged states and to investigate the autoionization dynamics of neutral or singly charged Ar in the vicinity of the double ionization threshold. 相似文献
124.
Andrea Piccolroaz Davide Bigoni 《International Journal of Solids and Structures》2009,46(20):3587-3596
Convexity of a yield function (or phase-transformation function) and its relations to convexity of the corresponding yield surface (or phase-transformation surface) is essential to the invention, definition and comparison with experiments of new yield (or phase-transformation) criteria. This issue was previously addressed only under the hypothesis of smoothness of the surface, but yield surfaces with corners (for instance, the Hill, Tresca or Coulomb–Mohr yield criteria) are known to be of fundamental importance in plasticity theory. The generalization of a proposition relating convexity of the function and the corresponding surface to nonsmooth yield and phase-transformation surfaces is provided in this paper, together with the (necessary to the proof) extension of a theorem on nonsmooth elastic potential functions. While the former of these generalizations is crucial for yield and phase-transformation functions, the latter may find applications for potential energy functions describing phase-transforming materials, or materials with discontinuous locking in tension, or contact of a body with a discrete elastic/frictional support. 相似文献
125.
Alessandro Sorrenti Marco Diociaiuti Valentina Corvaglia Pietro Chistolini Giovanna Mancini 《Tetrahedron: Asymmetry》2009,20(23):2737-2741
The recognition of the enantiomeric couples of ditryptophan in Langmuir films of N-hexadecanoyl-l-proline was investigated by surface pressure–area (π–A) isotherm measurements and Brewster angle microscopy experiments. The π–A isotherms relative to the films including the enantiomeric dipeptides show small differences whereas an evident enantiodiscrimination is observed by Brewster angle microscopy images. 相似文献
126.
Pietro Bollinger Philip Cooper Hans U. Gubler Albert Leutwiler Trevor Payne 《Helvetica chimica acta》1990,73(5):1197-1204
Compound (Z)- 8a has been found to display interesting antiinflammatory activity. In order to prepare derivatives with a wide variety of substituents in the aromatic part of the molecule, a new synthesis of the key intermediates 9a-g was developed starting from thiophene-3-carboxylic acid ( 11 ) and substituted benzyl bromides. The conversion of 9a-g to 10a-g follows a known procedure. Ketones 10a-g , on reaction with alkyl (dialkoxy-phosphoryl)acetate, followed by isomer separation and alkaline ester hydrolysis, yielded the desired derivatives (Z)- 8a-g and (E)- 8a-g . The biologically most interesting compound (Z)- 8a is currently undergoing clinical trials. 相似文献
127.
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
128.
129.
Rendiconti del Circolo Matematico di Palermo Series 1 - 相似文献
130.
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