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91.
Luisa Zanghirati 《Annali dell'Universita di Ferrara》1970,15(1):145-152
Riassunto In questa nota si indica il tipo della singolarità nell'origine della trasformata di Fourier di certe funzioni; mediante,
tale risultato si possono rapidamente ritrovare alcune maggiorazioni circa i nuclei di integrazione frazionaria anisotropa
già stabiliti daP. I. Lizorkin.
Summary In this paper the form of the singularity near the origine of the Fourier trasform of certain functions is shown; with the aid of this result some estimates for the kernel of non-isotropic fractional integration previously proved byP. I. Lizorkin are established in a very simple way.相似文献
92.
Franco Cristiani Francesco A. Devillanova Angelo Diaz Gaetano Verani 《Transition Metal Chemistry》1982,7(2):69-71
Summary OsO4 reacts with imidazolidine-2-thione and itsN-methyl andN-ethyl derivatives in acidified 11 vol. H2O:EtOH to give [OsL6]3+. Complexes obtained in the presence of HClO4 or HBF4 have been isolated as crystals and characterized by elemental analysis, i.r. spectroscopy and magnetic measurements.All the ligands bind the metal through the sulphur atom and the magnetic measurements are consistent with low spin osmium(III). The kinetics of [OsL6]3+ formation has been followed spectrophotometrically. Thepseudo-first order rate constants are linear both with respect to the acid and the ligand concentrations, indicating that the kinetically significant process involves one proton and one molecule of the ligand. A comparison of these results with those obtained for the analogous reaction with thiourea is reported. 相似文献
93.
Gaetano Villari 《Annali di Matematica Pura ed Applicata》1960,51(1):301-328
Sunto è contenuto nel n. 1 della Memoria.
A Giovanni Sansone nel suo 70mo compleanno. 相似文献
94.
Ultrathin ordered titanium oxide films on a Pt(111) surface have been prepared by reactive deposition and characterized by low-energy electron diffraction and scanning tunneling microscopy (STM). According to the postdeposition annealing condition, three different phases have been prepared which show a wagon-wheel-like (hereafter ww) morphological pattern. Two of them can be prepared as single phases (w- and w'-TiO(x)) and one (w(int)-TiO(x)) as a mixed phase which always coexists with at least one of the other two phases. All of them are formed by a Ti-O bilayer, where the Ti atoms are located at the interface with the substrate, but they show a rather distinct STM ww pattern. The experimental STM contrast has been discussed on the basis of a Moiré-like model, i.e., as deriving from a modulation of the Ti occupancy of the different substrate sites (i.e., hollow, bridge and on-top sites). The major part of the STM data can be easily interpreted on the basis of this simplified model. 相似文献
95.
We propose a model in which a recently reported modulation in the decay of the hydrogenlike ions 140Pr58+, 142Pm60+ and 122I52+ arises from the coupling of rotation to the spin of electron and nucleus. The model shows that the spin–spin coupling of electron and nucleus does not contribute to the modulation and predicts that the anomaly cannot be observed if the motion of the ions is rectilinear, or if the ions are stopped in a target. It also supports the notion that the modulation frequency is proportional to the inverse of the atomic mass and that no modulation is expected for the β+-decay. The model predicts that for He-like ions the modulation is still present. 相似文献
96.
The formation of a line of equally spaced particles at the centerline of a microchannel, referred as “particle ordering,” is desired in several microfluidic applications. Recent experiments and simulations highlighted the capability of viscoelastic fluids to form a row of particles characterized by a preferential spacing. When dealing with non-Newtonian fluids in microfluidics, the adherence condition of the liquid at the channel wall may be violated and the liquid can slip over the surface, possibly affecting the ordering efficiency. In this work, we investigate the effect of wall slip on the ordering of particles suspended in a viscoelastic liquid by numerical simulations. The dynamics of a triplet of particles in an infinite cylindrical channel is first addressed by solving the fluid and particle governing equations. The relative velocities computed for the three-particle system are used to predict the dynamics of a train of particles flowing in a long microchannel. The distributions of the interparticle spacing evaluated at different slip coefficients, linear particle concentrations, and distances from the channel inlet show that wall slip slows down the self-assembly mechanism. For strong slipping surfaces, no significant change of the initial microstructure is observed at low particle concentrations, whereas strings of particles in contact form at higher concentrations. The detrimental effect of wall slip on viscoelastic ordering suggests care when designing microdevices, especially in case of hydrophobic surfaces that may enhance the slipping phenomenon. 相似文献
97.
98.
99.
Several experimental techniques are used to study the short range order, the dynamics and the glass transition in AgIAg2B2O3 compounds. Addition of Ag2O to B2O3, up to [Ag2O]/[B2O3] ?0.5 modifies the borate network by creating a BO4 unit for each silver added. Addition of AgI decreases the glass transition temperature (Tg) but has only minor effects on the short range structure of the borate network. Silver iodide is partially accomodated in the interstices of the glass network. The relationship among a tentative structural picture, the ion transport phenomena and the low temperature dynamics are discussed.An investigation of the dynamics in the AgI·Ag2O·2B2O3 glass near and above Tg is presented. With NMR techniques, we monitor the onset of tumbling of the borate units and the dynamical effects of crystallization and/or aging of the glass. Hysteresis effects in the ionic conductivity (σ) temperature dependence and the non-Arrhenian behavior of σT near Tg are interpreted in terms of structural modifications occurring at elevated temperatures in the glass. 相似文献
100.
Zotti M Schiavone S Tricarico F Colaianna M D'Apolito O Paglia G Corso G Trabace L 《Journal of separation science》2008,31(13):2511-2515
Nitric oxide (NO) is one of the most important mediators and neurotransmitters and its levels change under pathological conditions. NO production may be regulated by endogenous nitric oxide synthase (NOS) inhibitors, in particular asymmetric dimethylarginine (ADMA). Most of the interest is focused on ADMA, since this compound is present in plasma and urine and accumulation of ADMA has been described in many disease states but little is known about cerebrospinal fluid (CSF) concentrations of this compound and of its structural isomer symmetric dimethylarginine (SDMA). To determine the levels of methylarginines, we here present a new hydrophilic interaction chromatography (HILIC)-MS/MS method for the precise determination of these substances in CSF from microdialysis samples of rat prefrontal cortex (PFC). The method requires only minimal sample preparation and features isotope-labelled internal standards. 相似文献