SOME REMARKS ABOUT THE AREA-PRESERVING CONVEX CURVE FLOW IN THE PLANE

Using Picard‘s theorem and the l.eray-Schauder fixed point theorem to reinvestigate the area-preserving convex curve flow in the plane which is considered as a coupled system and thus different from the setting handled by Gage.     

Dynamical and structural properties of titanium-decorated fullerene: A computer simulation study

We have investigated a material made of C₆₀Ti₆H₁₂ molecules using the classical molecular dynamic simulation. The system was studied in a wide range of temperatures, from solid to fluid. Several physical characteristics of endohedral fullerene were calculated for various temperatures: the mean square displacement, the translational and angular velocity autocorrelation function, the translational diffusion coefficient and the Lindemann index. We have observed a reduction in the rotational freedom of fullerene decorated with TiH₂ functionality groups in comparison with the pure fullerene sample.     

我国首张“5.1声道DVD质量样板试机碟(第一版)”出版发行

我国是DVD播放机和家庭影院放大器、扬声器系统的生产和消费大国。据有关行业协会统计,我国国产DVD播放机一年的销量达到3000万台,各种大大小小的国产家庭影院放大器超过700万台,国产扬声器系统则达1000万套以上,加上在我国销售的外国产品,我国消费者购买的数量则更为可观。     

Influence of oxygen on the structure of Nd-rich phase in the sintered Nd15Fe77B8 magnet

The structures and compositions of the Nd-rich phases in the sintered Nd₁₅Fe₇₇B₈ magnets have been investigated. Two different Nd-rich phases of the fcc and dhcp (double hexagonal close packed) structures were present. Microstructural examinations revealed that oxygen played an important role in the structure of the Nd-rich phase. Wavelength Dispersive Spectrometry (WDS) and Auger Electron Spectroscopy (AES) analyses showed that the fcc Nd-rich phase contained a considerable amount of oxygen (about 20 at%), but the dhcp Nd-rich phase had a much lower amount of oxygen.     

The proton relaxation timesT 1 in binuclear copper complexes

Proton spin-lattice relaxation times as a function of temperature for two kinds of binuclear copper complexes with antiferromagnetic exchange interactionJS₁S₂ have been measured in order to understand the relaxation effects in exchange clusters. It is shown that the results reflect the coupling of the nuclear and electron subsystems; in the rangekT<J the coupling of the subsystems is modulated by temperature independent processes, in the rangekT≥J the temperature dependence of the dynamics of the electron subsystem is manifested. The response of the nuclear subsystem to the change in the nature of magnetic excitations is discovered.     

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Data on classification of spectra and energy levels of atoms of rare earth elements with unfilled 4f-shells have been collected, systematized and analyzed. A brief account is given of methods for determining transition probabilities and lifetimes of the excited states of atoms and ions. Oscillator strengths for spectral lines of Nd(I), Sm(I), Eu(I), Gd(I), Dy(I), Tm(I) and Yb(I) have been measured using Rojdestvensky's hook method. Lifetimes of some of the excited states of Eu(I), Yb(I) and Yb(II) have been determined by using simultaneously the methods of delayed coincidence, hooks, and total absorption. Our results have been compared with those of other investigators. Atoms with unfilled 4f-shells show some regularities.     

On the Enskog-Thorne theory for a binary mixture of dissimilar rigid spheres

Thorne's method for obtaining transport coefficients in a binary rigid-sphere mixture is reexamined. First, a close look is taken at the way in which the point where the Enskog functionsx _ij are evaluated is introduced. Second, the calculation of the fluxes in the system and the transport coefficients is given. Thorne's results are found to be correct and independent of the choice of the point where the transfer plane is located. This does not hold true for the diffusion flux. It is shown that a different diffusion force is obtained for each selection and that only those diffusional effects which are of first order in the density are consistent with irreversible thermodynamics.     

The Cluster Model: A Simulation of the Aerogel Structure as a Hierarchically-Ordered Arrangement of Randomly Packed Spheres

A new structural model based on the premises widely used for describing the structure of aerogels has been introduced. These structures have been described as an assemblage of randomly-packed spheres in several hierarchically-ordered levels. A new algorithm has been developed for constructing our models from these premises using computer simulation. Subsequently, several applications have been simulated to characterize real systems, obtaining textural parameters such as the specific surface area, specific porous volume or the apparent density of the systems, based on the Monte Carlo technique and on geometrical considerations. The object of these is to test the ability of the models to explain the structure of some real aerogels. This Cluster Model has also been applied as an initial approach to the study of the mechanical properties of aerogels. Results support the general conclusion that these models are useful for explaining the structure of aerogels.     

Stability of a Cubically Convergent Method for Generalized Equations

In Geoffroy et al, Acceleration of convergence in Dontchev's iterative method for solving variational inclusions Serdica Math. J. 29 (2003), pp. 45–54] we showed the convergence of a cubic method for solving generalized equations of the form 0 ∈ f(x) +- G(x) where f is a function and G stands for a set-valued map. We investigate here the stability of such a method with respect to some perturbations. More precisely, we consider the perturbed equation y ∈ f(x) +- G(x) and we show that the pseudo-Lipschitzness of the map (f +- G)⁻¹ is closely tied to the uniformity of our method in the sense that the attraction region does not depend on small perturbations of the parameter y. Finally, we provide an enhanced version of the convergence theorem established by Geoffroy, et al.     

UV photolysis of C4N2 in water ices: new possible route of synthesis of ammonium bicarbonate and ammonium formate

Laboratory experiments involving ultraviolet (UV) irradiation of dicyanoacetylene (C(4)N(2)) trapped in water ice at 10 K have been conducted and monitored by infrared spectroscopy (FTIR). By the support of isotopic experiments and theoretical calculations, the irradiation of a DCA/H(2)O ice mixture at lambda > 230 nm has been found to be a possible source of NH(4)(+)HCO(3)(-) (ammonium bicarbonate) and NH(4)(+)HCOO(-) (ammonium formate). These latter compounds can arise from a proton-transfer reaction between H(2)O and the CN radical, which is issued from photolyzed C(4)N(2).