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1.
Pierluigi Contucci Sandro Graffi Stefano Isola 《Journal of statistical physics》2002,106(5-6):895-914
For the long-range deterministic spin models with glassy behaviour of Marinari, Parisi and Ritort we prove weighted factorization properties of the correlation functions which represent the natural generalization of the factorization rules valid for the Curie–Weiss case. 相似文献
2.
We use boundary value methods to compute consistent initial values for fully implicit nonlinear differential-algebraic equations.
The obtained algorithm uses variable order formulae and a deferred correction technique to evaluate the error. A rigorous
theory is stated for nonlinear index 1, 2 and 3 DAEs of Hessenberg form. Numerical tests on classical index 1, 2 and 3 DAE
problems are reported.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
Pierluigi Contucci 《Journal of statistical physics》1996,82(5-6):1647-1657
We study the coexistence phase in the two-dimensional Ising model. Optimizing the cluster expansion technique, we are able to prove the phase separation phenomenon, with the Onsager value for the surface tension, in a range
, where
estimates from above the critical within 19% and essentially coincides with the entropic bound. 相似文献
4.
Bruno Crociani Umberto Belluco Pierluigi Sandrini 《Journal of organometallic chemistry》1979,177(2):385-401
The reactions of the organometallic 1,4-diazabutadienes, RN=C(R′)C(Me)=NR″ [R = R″ = p-C6H4OMe, R′ = trans-PdCl(PPh3)2 (DAB); R = p-C6H4OMe, R″ = Me, R′ = trans-PdCl(PPh3)2 (DABI; R = R″ = p-C6H4OMe, R′ = Pd(dmtc)-(PPh3), dmtc = dimethyldithiocarbamate (DABII); R = R″ = p-C6H4OMe, R′ = PdCl(diphos), diphos = 1,2-bis(diphenylphosphino)ethane (DABIII)] with [RhCl(COD)]2 (COD = 1,5-cyclooctadiene, Pd/Rh ratio = ) depend on the nature of the ancillary ligands at the Pd atom in group R′. In the reactions with DAB and DABI transfer of one PPh3 ligand from Pd to Rh occurs yielding [RhCl(COD)(PPh3)] and the new binuclear complexes [Rh(COD) {RN=C(R?)-C(Me)=NR″}], in which the diazabutadiene moiety acts as a chelating bidentate ligand. Exchange of ligands between the two different metallic centers also occurs in the reaction with DABII. In this case, the migration of the bidentate dmtc anion yields [Rh(COD)Pdmtc] and [Rh(COD) {RN=C(R?)C(Me)=NR″}]. In contrast, the reaction with DABIII leads to the ionic product [Rh(COD)- (DABIII)][RhCl2(COD)], with no transfer of ligands. The cationic complex [Rh(COD)(DABIII)]+ can be isolated as the perchlorate salt from the same reaction (Pd/Rh ratio = 1/1) in the presence of an excess of NaClO4. In all the binuclear complexes the coordinated 1,5-cyclooctadiene can be readily displaced by carbon monoxide to give the corresponding dicarbonyl derivatives. The reaction of [RhCl(CO)2]2 with DAB and/or DABI yields trinuclear complexes of the type [RhCl(CO)2]2(DAB), in which the diazabutadiene group acts as a bridging bidentate ligand. Some reactions of the organic diazabutadiene RN=C(Me)C(Me)=NR (R = p-C6H4OMe) are also reported for comparison. 相似文献
5.
Density functional theory calculations at the B3LYP/6-31G* level on the dimerization reactions of acetonitrile oxide and para-chlorobenzonitrile oxide to form furoxans indicate that these processes are stepwise involving dinitrosoalkene intermediates that have considerable diradical character. The rate-determining steps for these two reactions correspond to C-C bond formation. The retardation of dimerization in aromatic nitrile oxides arises from the interruption of conjugation between the nitrile oxide and aryl groups in the C-C bond formation step. The present study also suggests that the isomerization of single-ring furoxans occurs via a diradical intermediate mechanism. 相似文献
6.
Birendra Kumar Deepti Tikariha M. L. Satnami Nadia Barbero Pierluigi Quagliotto Kallol K. Ghosh 《Journal of Physical Organic Chemistry》2014,27(7):613-621
The catalytic hydrolysis of bis(4‐nitrophenyl)phosphate (BNPP) and bis(2,4‐dinitrophenyl)phosphate (BDNPP) catalyzed by α‐nucleophiles in gemini micellar media was investigated at 27 °C. The cationic gemini surfactants, i.e., alkanediyl‐α‐ω‐bis(hydroxyethylmethylhexadecylammonium bromide) (16‐s‐16 MEA 2Br?, where s = 4 and 6) were used. Nucleophilic reactivity of α‐nucleophiles such as hydroperoxide (HOO?), acetohydroxamate (AHA?), and butane 2,3‐dione monoximate ions (BDMO?) were compared. The kinetic rate data were treated by applying the pseudophase model. The cationic gemini surfactants show unusual rate acceleration toward the cleavage of phosphodiesters with nucleophiles. These studies reveal that the hydroperoxide ion shows the highest catalytic activity reported so far with an unprecedented acceleration rate, 107 times faster than that of the uncatalyzed reaction. The possible mechanism for the BNPP and BDNPP cleavage promoted by α‐nucleophiles is proposed on the basis of kinetic analysis. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
7.
8.
In this research, we develop and introduce a theoretical and mathematical forecasting framework of immigrant integration using immigrant density as a single driver. First, we introduce the integration concepts we aim at forecasting. Thereafter, we introduce a theoretical and mathematical model of the relationship between integration and immigrant density. Based on this model, we develop a methodological forecasting framework. We test the framework using immigrant integration data from Spain. We produce the forecasts, and conduct the proper evaluation of them. Finally, we conclude with a brief discussion of the wider implications of our results. 相似文献
9.
We introduce symmetric Boundary Value Methods for the solution of second order initial and boundary value problems (in particular
Hamiltonian problems). We study the conditioning of the methods and link it to the boundary loci of the roots of the associated
characteristic polynomial. Some numerical tests are provided to assess their reliability.
Dedicated to the memory of Professor Aldo Cossu 相似文献
10.
Nadaniela Egidi Romina Gobbi Pierluigi Maponi 《Journal of Computational and Applied Mathematics》2007,210(1-2):175-182
We consider an electromagnetic scattering problem for inhomogeneous media. In particular, we focus on the numerical computation of the electromagnetic scattered wave generated by the interaction of an electromagnetic plane wave and an inhomogeneity in the corresponding propagation medium. This problem is studied in the VV polarization case, where some special symmetry requirements for the incident wave and for the inhomogeneity are assumed. This problem is reformulated as a Fredholm integral equation of second kind, which is discretized by a linear system having a special form. This allows to compute efficiently an approximate solution of the scattering problem by using iterative techniques for linear systems. Some numerical examples are reported. 相似文献