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1.
Visintin RF Lapasin R Vignati E D'Antona P Lockhart TP 《Langmuir : the ACS journal of surfaces and colloids》2005,21(14):6240-6249
A waxy crude oil which gels below a threshold temperature has been investigated under static and dynamic conditions, using a combination of rheological methods, optical microscopy, and DSC. Particular attention is given in this work to the influence of the mechanical history on gel strength and to describing the time-dependent rheological behavior. The gels display a strong dependence of the yield stress and moduli on the shear history, cooling rate, and stress loading rate. Of particular interest is the partial recovery of the gel structure after application of small stress or strain (much smaller than the critical values needed for flow onset) during cooling, which can be used to reduce the ultimate strength of the crude oil gel formed below the pour point. A second focus of this study is to further develop the physical interpretation of the mechanism by which wax crystallization produces gelation. Gelation of the waxy crude oil studied is suggested to be the result of the association between wax crystals, which produces an extended network structure, and it is shown that the system displays features common to attractive colloidal gels, for one of which, fumed silica (Aerosil 200) in paraffin oil, rheological data are reported. The colloidal gel model provides a simple and economical basis for explaining the response of the gelled oil to various mechanical perturbations and constitutes a fruitful basis from which to develop technologies for controlling the gelation phenomenon, as suggested by the rheological results reported. 相似文献
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Anita Tabacco Vignati 《Annali di Matematica Pura ed Applicata》1994,166(1):145-153
Sia D il dominio di Siegel e Hn il gruppo di Heisenberg. Si considera il sistema ortogonale ottenuto dai monomi normalizzati delta palla unitaria di
n+1 tramite la trasformata di Cayley. La trasformata di Fourier di tali funzioni ristrette ad Hn viene esplicitamente calcolata. Rispetto alla base di Hermite di L2(
n
), si ottengono operatori di rango uno espressi in termini di funzioni di Laguerre. 相似文献
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Piazza R Pierno M Vignati E Venturoli G Francia F Mallardi A Palazzo G 《Physical review letters》2003,90(20):208101
Solubilization of membrane proteins requires surfactants, whose structural properties play a crucial role in determining the protein phase behavior. We show that ionization of a pH-sensitive surfactant, lauryldymethylamino-N-oxide, bound to the bacterial photosynthetic Reaction Center, induces protein phase segregation in micrometric "droplets." Liquid-liquid phase separation takes place in a narrow pH range, is promoted by increasing temperature, and vanishes by adding salt. After a fast initial droplet growth, the nearly arrested kinetics at a later stage leaves the system in a finely divided, long-lasting emulsified state. 相似文献
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A technique for measuring small signal gain and its uniformity across an optical aperture in e-beam controlled CO2 laser amplifiers is described. Results for a 100 J laser prototype, built in the Frascati laboratories, are reported. 相似文献
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S. Ciuchi L. Maiani A. D. Polosa V. Riquer G. Ruocco M. Vignati 《The European Physical Journal C - Particles and Fields》2012,72(10):1-3
It has recently been argued that inverse-?? nuclear transmutations might occur at an impressively high rate in a thin layer at a metallic hydride surface under specific conditions. In this note we present a calculation of the transmutation rate, which shows that there is little room for such a remarkable effect. 相似文献
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C. Arnaboldi C. Brofferio A. Bryant C. Bucci L. Canonica S. Capelli M. Carrettoni M. Clemenza I. Dafinei S. Di Domizio F. Ferroni E. Fiorini Z. Ge A. Giachero L. Gironi A. Giuliani P. Gorla E. Guardincerri R. Kadel K. Kazkaz L. Kogler Y. Kolomensky J. Larsen M. Laubenstein Y. Li C. Maiano M. Martinez R. Maruyama S. Nisi C. Nones Eric B. Norman A. Nucciotti F. Orio L. Pattavina M. Pavan G. Pessina S. Pirro E. Previtali C. Rusconi Nicholas D. Scielzo M. Sisti Alan R. Smith W. Tian M. Vignati H. Wang Y. Zhu 《Journal of Crystal Growth》2010,312(20):2999-3008
High purity TeO2 crystals are produced to be used for the search for the neutrinoless double beta decay of 130Te. Dedicated production lines for raw material synthesis, crystal growth, and surface processing were built compliant with radio-purity constraints specific to rare event physics experiments. High sensitivity measurements of radio-isotope concentrations in raw materials, reactants, consumables, ancillaries, and intermediary products used for TeO2 crystals production are reported. Indications are given on the crystals perfection and how it is achieved and maintained in a large scale production process. Production and certification protocols are presented and resulting ready-to-use TeO2 crystals are described. 相似文献
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O. Azzolini M. T. Barrera J. W. Beeman F. Bellini M. Beretta M. Biassoni E. Bossio C. Brofferio C. Bucci L. Canonica S. Capelli L. Cardani P. Carniti N. Casali L. Cassina M. Clemenza O. Cremonesi A. Cruciani A. D’Addabbo I. Dafinei S. Di Domizio F. Ferroni L. Gironi A. Giuliani P. Gorla C. Gotti G. Keppel M. Martinez S. Morganti S. Nagorny M. Nastasi S. Nisi C. Nones D. Orlandi L. Pagnanini M. Pallavicini V. Palmieri L. Pattavina M. Pavan G. Pessina V. Pettinacci S. Pirro S. Pozzi E. Previtali A. Puiu C. Rusconi K. Schäffner C. Tomei M. Vignati A. Zolotarova 《The European Physical Journal C - Particles and Fields》2018,78(11):888
The CUPID-0 experiment searches for double beta decay using cryogenic calorimeters with double (heat and light) read-out. The detector, consisting of 24 ZnSe crystals 95\(\%\) enriched in \(^{82}\)Se and two natural ZnSe crystals, started data-taking in 2017 at Laboratori Nazionali del Gran Sasso. We present the search for the neutrino-less double beta decay of \(^{82}\)Se into the 0\(_1^+\), 2\(_1^+\) and 2\(_2^+\) excited states of \(^{82}\)Kr with an exposure of 5.74 kg\(\cdot \)yr (2.24\(\times \)10\(^{25}\) emitters\(\cdot \)yr). We found no evidence of the decays and set the most stringent limits on the widths of these processes: \(\varGamma \)(\(^{82}\)Se \(\rightarrow ^{82}\)Kr\(_{0_1^+}\))8.55\(\times \)10\(^{-24}\) yr\(^{-1}\), \(\varGamma \) (\(^{82}\) Se \(\rightarrow ^{82}\) Kr \(_{2_1^+}\))\(\,{<}\,6.25 \,{\times }\,10^{-24}\) yr\(^{-1}\), \(\varGamma \)(\(^{82}\)Se \(\rightarrow ^{82}\)Kr\(_{2_2^+}\))8.25\(\times \)10\(^{-24}\) yr\(^{-1}\) (90\(\%\) credible interval). 相似文献