Convergence of bivariate cardinal interpolation

We give necessary and sufficient conditions for the convergence of cardinal interpolation with bivariate box splines as the degree tends to infinity.     

Positive definiteness and positive differences

A previous inequality [2] in certain context, which holds in the application to the monotonicity of correlations in classical discrete Heisenberg ferromagnets with 2-dimensional spin [3], is extended to positive definiteness of a function on a group.     

The thermal degradation of acrylic acid–ethylene polymers

A Study of the thermal degradation of a copolymer of ethylene and acrylic acid is presented. The degradation mechanism of the acrylic acid portion of the polymer was found to be dehydration of the acid, forming anhydride, and decarboxylation of the anhydride, forming unsaturation. The resultant unsaturation reduces the copolymer-s stability to both thermal and oxidative degradation.     

Dielektrische Eigenschaften von Benzin-in-Wasser-Mikroemulsionen im Frequenz-bereich 100 kHz bis 5 MHz

Ohne Zusammenfassung     

A general integrated process for synthesizing olefin oxides

Metal oxide solid reactants are shown to react with vicinal alkyl dibromides to selectively form olefin oxides and fully regenerable metal bromides.     

Sound attenuation study on the bose-Einstein condensation of magnons in TlCuCl3

We investigate experimentally and theoretically sound attenuation in the quantum spin system TlCuCl3 in magnetic fields at low temperatures. Near the point of Bose-Einstein condensation of magnons a sharp peak in the sound attenuation is observed. The peak demonstrates a hysteresis as a function of the magnetic field pointing to a first-order contribution to the transition. The sound damping has a Drude-like form arising as a result of hard-core magnon-magnon collisions. The strength of the coupling between lattice and magnons is estimated from the experimental data. The puzzling relationship between the transition temperature and the concentration of magnons is explained by their "relativistic" dispersion.     

Spin relaxation in nanowires by hyperfine coupling

Hyperfine interactions establish limits on spin dynamics and relaxation rates in ensembles of semiconductor quantum dots. It is the confinement of electrons which determines nonzero hyperfine coupling and leads to the spin relaxation. As a result, in nanowires one would expect the vanishing of this effect due to extended electron states. However, even for relatively clean wires, disorder plays a crucial role and makes electron localization sufficient to cause spin relaxation on the time scale of the order of 10 ns. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Atmospheric CO2 and destructivity of the land biota: Seasonal variations

Summary The seasonal variations of the carbon content in the ocean are shown to be small as compared to those taking place in the atmosphere. Atmospheric meridional mixing is not intense enough to compensate for the variations of the atmospheric CO₂. If we assume meridional mixing to be zero, then the seasonal variations of carbon in the atmospheric column should be equal to those of carbon in the continental bionass but opposite to them in sign. This latter value is essentially the difference between productivity and destructivity of the land biomass Productivity of humid areas at any latitude is proportional to the diurnal mean solar radiation flux at that latitude. In the present study the temporal variations of this flux are harmonically approximated. Further, an harmonic approximation is found for expressing the temporal course of biomass destructivity at various latitudes. Productivity/destructivity oscillations appear to be almost in couterphase but amplitudinally close to each other.

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Riassunto Le variazioni stagionali del contenuto di carbonio nell'oceano sono piccole rispetto a quelle che si verificano nell'atmosfera. Il mescolamento atmosferico meridionale non è abbastanza intenso da compensare le variazioni del CO₂ atmosferico. Se si ammette che il mescolamento sia zero, le variazioni stagionali del carbonio nella colonna atmo-sferica dovrebbero essere uguali a quelle del carbonio nella biomassa continentale ma opposte a queste ultime come segno. Quest'ultimo valore è essenzialmente la differenza tra la produttività e la distruttività nella biomassa terrestre. La produttività delle aree umide ad ogni latitudine è proporzionale al flusso di radiazione solare diurno medio a quella latitudine. In questo studio si approssimano armonicamente le variazioni temporali di questo flusso. Inoltre si trova un'approssimazione armonica per esprimere l'andamento temporale della distruttività della biomassa a varie latitudini. Le oscillazioni di producttività/distruttività sembrano quasi in controfase ma prossime l'una all'altra per quanto riguarda l'ampiezza.

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Резюме Показано, что сезонные изменения содержания углерода в океане малы по сравнению с изменениями в атмосфере. Меридионаляное перемешивание атмосферы не успевает выравнивать атмосферные колебания CO₂. В приближении нулевого меридионляного перемешиваиия сезонные колебания содержания углерода в атмосферном столбе равны по величине и противололожны по знаку изменению содерзания углерода в континентальной биомассе, иоторое равно разности продуктивности и деструктивности. Продуктивность гумидных областей на разных широтах пропорционаляна среднесуточному потоку солнечной радиации на зтих широтах. В работе найдено гармоническое привлижение для изменения во времени последних величин. С помощью зтих данных определено гармоническое приближение для поведения во времени деструктивности на ражных широтах. Колебание продуктивности и деструктивности оказались происходящими почти в противофазя с близкими по величине амплитудами.