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51.
Rinaldo?M.?ColomboEmail author Andrea?Corli 《NoDEA : Nonlinear Differential Equations and Applications》2003,10(3):255-268
We deal with a strictly hyperbolic system of two conservation laws in one spatial dimension.
One of the eigenvalues of the system is of Temple type (rarefaction and shock curves coincide), the
other eigenvalue is only required to be genuinely nonlinear.We consider the initial value problem
for data of the following kind: the total variation of the Temple component is bounded, possibly
large, while the total variation of the other component is small. For such data we prove global
existence, uniqueness and L⊃-Lipschitz
continuous dependence of solutions.AMS Subject Classification: Primary 35L65; Secondary 35D05, 35L45. 相似文献
52.
This paper develops the basic analytical theory related to some recently introduced crowd dynamics models.Where well posedness was known only locally in time,it is here extended to all of R+.The result... 相似文献
53.
Giovanna Bruni Vittorio Berbenni Franco Sartor Chiara Milanese Alessandro Girella Dionigio Franchi Amedeo Marini 《Journal of Thermal Analysis and Calorimetry》2012,108(1):235-241
In this work, thermoanalytical, diffractometry, and microscopy measurements have been performed in order to characterize the
effect of high energy milling on a drug active in the migraine prophylaxis and smoke cessation. We can assert that the mechanical
treatment induces only a partial amorphisation of the solid phase, in particular it reduces the crystal order by producing
lattice defects which propagate from the surface to the bulk crystal. For this reason, the DSC is able to detect the presence
of ordered solid, while the powder X-ray diffractometry, because of its low penetration depth, does not reach the crystalline
core of the particles. 相似文献
54.
Rinaldo M. Colombo Massimiliano D. Rosini 《Mathematical Methods in the Applied Sciences》2005,28(13):1553-1567
We present a model for the flow of pedestrians that describes features typical of this flow, such as the fall due to panic in the outflow of people through a door. The mathematical techniques essentially depend on the use of non‐classical shocks in scalar conservation laws. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Abbandonato G Catalano D Marini A 《Langmuir : the ACS journal of surfaces and colloids》2010,26(22):16762-16770
The aggregation of perfluoroctanoate salts in H(2)O is studied by (19)F NMR on solutions of LiPFO, NaPFO, and CsPFO, without and with the addition of two poly(ethylene glycol) (PEG) oligomers of molecular weight 1500 and 3400 Da, respectively, and with the addition of suitable crown ethers. The (19)F chemical shift (cs) trends are monitored, at 25 °C, in a concentration range including the critical micellar concentration (cmc) or, in the presence of PEG, the critical aggregation concentration (cac). The cac values in the samples with PEG are lower than the cmc values of the corresponding samples without PEG; moreover, the (19)F cs trends above the cac and above the polymer saturation concentration reveal and help to explain some peculiarities of the aggregation process of PEG on PFO micelles, which, in the first step, seems to occur while the surfactant concentration in water is still increasing. Also in LiPFO/H(2)O or NaPFO/H(2)O solutions containing 12-crown-4 or 15-crown-5 ethers, suitable to complex Li(+) or Na(+) ions, respectively, the cmc decreases. On the other hand, the micellization process in the presence of crown ethers does not show other peculiarities. The prevailing conformations of the PFO chain are discussed on the basis of quantum-mechanical calculations. The theoretical chemical shifts were computed at the DFT level of theory, taking into account the effects of the environment by means of the IEF-PCM method. The helical structure is the most stable one, but anti conformations are easily accessible, in both the aqueous and fluorinated environment. The comparison between computed and experimental chemical shifts indicates that anti conformations are more important in the micelles than in water and in CsPFO micelles than in LiPFO or NaPFO ones. 相似文献
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Classic Briggs-Rauscher oscillators use malonic acid (MA) as a substrate. The first organic product is iodomalonic acid. Iodomalonic acid (IMA) can serve as a substrate also; thus, the first product in that case is diiodomalonic acid (I(2)MA). Nonoscillating iodination kinetics can be followed by absorbance at 462 nm in acidic KIO(3) so long as IMA is in substantial excess over [I(2)]. At 25 °C, simulations lead to the two most important rate laws, and related rate constant estimates are reported. I(2)MA eventually decomposes by unknown processes, but I(2), O(2), H(2)O(2), and Mn(2+) speed up that decomposition, liberating most of the iodine back to the solution. Resorcinol is an effective inhibitor of oscillations both in MA oscillators and in IMA oscillators. Response of an IMA oscillator to varying amounts of resorcinol is shown herein and is similar to that for MA-based oscillators. The inhibitory effect of resorcinol is diminished by addition of IMA to a MA-based oscillator. The iodination reaction between IMA and resorcinol is too slow (0.043 M(-1) s(-1)) to account for the decreased inhibitory effectiveness of resorcinol. Rather, the decomposition of I(2)MA is responsible for the inhibition decrease. 相似文献
60.
We study the second order Emden–Fowler type differential equation in the super-linear case α<β. Using a Hölder-type inequality, we resolve the open problem on the possible coexistence on three possible types of nononscillatory solutions (subdominant, intermediate, and dominant solutions). Jointly with this, sufficient conditions for the existence of globally positive intermediate solutions are established. Some of our results are new also for the Emden–Fowler equation. 相似文献
(a(t)|x′|αsgnx′)′+b(t)|x|βsgnx=0