Osservazioni su alcuni operatori ibridi iperbolico-ipoellittici

Riassunto Viene dimostrata l'equivalenza di alcune condizioni sul polinomio a coefficienti costantiP(ζ). La prima (si vedaH?rmander [3]), garantisce l'esistenza di una soluzione fondamentale diP(D) con supporto singolare in un cono convesso; l'ultima esprime il carattere ibrido diP(ζ). Viene infine costruita una soluzione fondamentale ultradistribuzione per un operatore 1/β-iperbolico-1/α-ipoellittico estendendo un precedente risultato [5] dell'autore.

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Summary The equivalence of some conditions on the polynomialP(ζ) with constant coefficients is proved. The first one (seeH?rmander [3]), implies the existence of a fundamental solution forP(D) with singular support contained in a convex cone; the last one shows thatP(ζ) is an hyperbolic-hypoelliptic polynomial. Finally an ultradistribution fundamental solution for a 1/β-hyperbolic-1/α-hypoelliptic operator is constructed, so extending a previous result [5] of the author.

     

不用外接电阻器时增益为2的仪表放大器

仪表放大器不用反馈电阻器就能提供精确的增益,并且,在任何增益值下,它的非反相和反相输入端都有高输入阻抗.在一个典型的IC仪表放大器中,连接两个增益调整脚的单只电阻器就能确定电路的总增益.     

Violacein/β-Cyclodextrin Inclusion Complex Formation Studied by Measurements of Diffusion Coefficient and Circular Dichroism

The formation of inclusion compounds between violacein and-cyclodextrin was studied by diffusion and circulardichroism measurements. The present work was undertaken to explore the feasibilityof the -cyclodextrin in reducing the toxicity and enhancing the antitumoral efficacy ofviolacein by forming an inclusion complex. The results of the two experimentsare in good agreement, suggesting the formation of 1 : 1 and 1 : 2 complexes.The diffusion coefficient measurements enabled estimates of the sizes of the complexesinvolved. From the circular dichroism and computational calculations it was possibleto view a preference for inclusion of the most polar part of the molecule to form a1 : 2 inclusion complex. We expect that this work proves the potential of thesetechniques to determining complex stoichiometry.     

Electrical and electrochemical behaviour of several LiFe<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Co<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>PO<Subscript>4</Subscript> solid solutions as cathode materials for lithium ion batteries

Several olivine phosphates were investigated in the last years as cathode materials for secondary lithium ion batteries. Among these compounds, LiFe _x Co_1 − x PO₄ solid solutions might be interesting candidates because they should combine the high potential value of Co³⁺/Co²⁺ (higher than 4.5 V vs Li⁺/Li) with the relatively high charge–discharge rate of LiFePO₄. Solid solutions were prepared by solid-state route and characterised by X-ray powder diffraction, cyclic voltammetry, impedance spectroscopy and the Hebb–Wagner method. The results show that also low amount of iron induces high electronic conductivity in the solid solutions.     

On fractional powers of a pair of matrices and a plate-beam problem

In this paper we consider the transversal deflections of a dynamically-coupled Von Kármán system consisting of a plate which has a beam attached to its one edge. The problem is considered in the form of a non-linear evolution problem in a product space. We show the existence of a unique local solution by following a fractional powers approach to first construct a “weak” solution in a larger space. Regularity properties for this solution yield a unique local strong solution for the original boundary-value problem. This approach entails the introduction of fractional powers of a pair of matrices.     

A note on Robinson–Ursescu and Lyusternik–Graves theorem

The aim of this note is twofold. First, we prove an analogue of the well-known Robinson–Ursescu Theorem on the relative openness with a linear rate (restrictive metric regularity) of a multivalued mapping. Second, we prove a generalization of Graves Open Mapping Theorem for a class of mappings which can be approximated at a reference point by a bunch of linear mappings. The approximated non-linear mapping is restricted to a closed convex subset of a Banach space.     

Reproducing Subgroups of Sp(2,\mathbb{R}). Part I: Algebraic Classification

We classify the connected Lie subgroups of the symplectic group $Sp(2,{\mathbb{R}})$ whose elements are matrices in block lower triangular form. The classification is up to conjugation within $Sp(2,{\mathbb{R}})$ . Their study is motivated by the need of a unified approach to continuous 2D signal analyses, as those provided by wavelets and shearlets.     

Preparation of 3-(4-chlorophenyl)-2-(2-aminothiazol-4-yl)-5-methoxybenzo[b]furan derivatives and their leukotriene B(4) inhibitory activity

A series of 3-(4-chlorophenyl)-2-(2-aminothiazol-4-yl)benzo[b]furan derivatives 6-10 were prepared and their leukotriene B(4) inhibitory activity was evaluated. We found that several compounds showed strong inhibition of calcium mobilization in CHO cells overexpressing human BLT(1) and BLT(2) receptors. Among them, 3-(4-chlorophenyl)-2-[5-formyl-2-[(dimethylamino)methyleneamino]thiazol-4-yl]-5-methoxybenzo[b]furan 9b showed the most potent and selective inhibition for the human BLT(2) receptor, and its IC(50) value was smaller than that of the selected positive control compound, ZK-158252.     

Determination of ammonium in wastewaters by capillary electrophoresis on a column-coupling chip with conductivity detection

Analytical potentialities of a chip-based CE in determination of ammonium in wastewaters were investigated. CZE with the electric field and/or ITP sample stacking was performed on a column-coupling (CC) chip with integrated conductivity detectors. Acetate background electrolytes (pH ～3) including 18-crown-6-ether (18-crown-6) and tartaric acid were developed to reach rapid (in 7-8 min) CZE and ITP-CZE resolutions of ammonium from other cations (sodium, potassium, calcium and magnesium) present in wastewater samples. Under preferred working conditions (suppressed hydrodynamic flow (HDF) and EOF on the column-coupling chip), both the employed methods did provide very good repeatabilities of the migration (RSD of 0.2-0.8% for the migration time) and quantitative (RSD of 0.3-4.9% for the peak area) parameters in the model and wastewater samples. Using a 900-nL sample injection volume, LOD for ammonium were obtained at 20 and 40 μg/L concentrations in CZE and ITP-CZE separations, respectively. Very good agreements of the CZE and ITP-CZE determinations of ammonium in six untreated wastewater samples (only filtration and dilution) with the results obtained by a reference spectrometric method indicate a very good accuracy of both the CE methods presented.