Synthesis and Reactions of a New Quinone Quinoline 7‐(Carboxymethoxy)‐3‐sulfoquinoline‐5,6‐dione

The new ortho‐quinone quinoline 7‐(carboxymethoxy)‐3‐sulfoquinoline‐5,6‐dione was synthesized. The reaction of this quinoline‐5,6‐dione with hydroxylamine, hydrazine, phenylhydrazine, ethanol, semicarbazide, thiosemicarbazide, ethylenediamine, and benzene‐1,2‐diamine were studied. Ten new azaheterocyclic compounds were isolated and characterized by elemental analyses, IR, 1D NMR, 2D NMR, and MS spectra. Antioxidant activities of some obtained compounds were tested.     

A free boundary problem for the Navier–Stokes equations with measure data

The existence of a weak solution of an initial boundary-value problem for the plane nonstationary Navier–Stokes equations with Radon measure data on the free boundary, is established. The problem may be considered as a model of the blood flow around the heart valves. An inverse problem is studied, it allows us to find the boundary forces acting on the valve from the observed values of the velocity of the fluid in a fixed subregion.     

On an exact control problem for a semilinear wave equation with an unknown source

The exact controllability of a semilinear wave equation, with Dirichlet boundary control on a part of the boundary and an unknown source, is shown. The nonlinear term has at most a linear growth, the initial and target spaces are L²(Ω)×H⁻¹(Ω).     

Affine Systems that Span Lebesgue Spaces

We establish rather weak conditions on under which the small scale affine system spans . The conditions are that the periodization of |ψ| be locally in L^p, that , and that the dilation matrices a_j are expanding, meaning . The periodization of ψ need not be constant; that is, the integer translates need not form a partition of unity. The proof involves explicitly approximating an arbitrary function f using a linear combination of the , with the coefficients in the linear combination being local average values of f .     

Short-period variation of cosmic-ray intensity observed in the stratosphere

Summary To investigate the variation of the cosmic-ray intensity in the Earth atmosphere, stratospheric balloon soundings are performed weekly at Campinas (Brazil). During the flight of May 20th, 1988 short-period variations were detected. Through Fourier analysis it was identified a period of ∼2.5 min, with a confidence level of 99.6% between 23 g/cm² and 173 g/cm². Apparently these oscillations are not correlated either with the earth magnetic field or solar activity, suggesting their atmospheric origin, nevertheless it is difficult to explain the production mechanisms of these disturbances.

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Riassunto Per studiare le variazioni dell'intensità dei raggi cosmici nell'atmosfera terrestre sono messi in funzione palloni sonda stratosferici settimanalmente a Campinas (Brasile). Durante il volo del 20 Maggio 1988 sono state registrate variazioni a breve periodo. Mediante l'analisi di Fourier è stato identificato un periodo di ≈2.5 min con un livello di confidenza di 99.6% tra 23 g/cm² e 173 g/cm². Apparentemente queste oscillazioni non sono correlate né con il campo magnetico terrestre né con l'attività solare, il che suggerisce la loro origine atmosferica, nonostante sia difficile spiegare i meccanismi di produzione di queste perturbazioni.

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Резюме для исследования изменения интенсивности комсических лучей в земной атмосфере еженелельно запускайтся стратосферные шарызонды в лаборатории Кампинас (Бразилия). Во время подыта 20 мая 1988 года, были зарегистрированы изменения с коротким периодом. С помощью фурье-анализа определен период 2.5 минуты, с уровнем достоверности 99.6%, в области между 23 г/см² и 173 г/см². По-видимому, эти осцилляции не связаны ни с магнитным полем Земли, ни с солнечной активностью. Предполагается их атмосферное происхождение, тем не менее трудно обБяснить механизм образования этих возмущений.

     

Ionic conductivity and tensile properties of hydroxyethyl and hydroxypropyl chitosan membranes

Hydroxyethyl chitosan and hydroxypropyl chitosan were prepared through the reaction of alkali‐chitosan with 2‐chloroethanol and propylene epoxide, respectively. Fourier transform infrared and ¹³C NMR measurements were made to examine the substitution on the chitosan unit. According to a comparison of the peak areas between the modified chitosan and unmodified chitosan and the integration of peak areas of ¹H NMR spectra, for both modified chitosans, the maximum degree of substitution was less than 25%. The ionic conductivity and mechanical properties of modified chitosan membranes were investigated. In comparison with the unmodified chitosan membrane, hydrated hydroxyethyl and hydroxypropyl chitosan membranes with a higher degree of substitution showed an increase in ionic conductivity of about one order of magnitude; moreover, the crystallinity of hydroxyethyl and hydroxypropyl chitosan membranes was remarkably reduced, and their swelling indices increased significantly. However, these modified membranes did not exhibit significant changes in their tensile strength and breaking elongation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1379–1397, 2004