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991.
Production of natural and synthesized aluminum-based composite materials with the aid of ultrasonic (cavitation) treatment of the melt 总被引:4,自引:0,他引:4
The application of ultrasonic melt treatment to the production of natural and synthesized aluminum-based composite materials is considered in terms of underlying basic ideas and commercial implementations. It is shown that the ultrasonic cavitation treatment combined with microalloying of hypereutectic Al-Si natural composites (alloys) promotes the formation of structures suitable for further deformation. The use of highly impure starting materials becomes also possible. The combination of ultrasonic cavitation treatment with electromagnetic stirring allows one to considerably improve the size and spatial distribution of ceramic particles in metal-matrix composites. 相似文献
992.
The processes of substance evaporation and atom ionization under different conditions of spark discharge or laser radiation are considered. It is shown that the dependence of the relative sensitivity coefficients on the properties of an element can be presented as the product of two exponents with parameters proportional to the atomization energies and first ionization potentials of the element. Differences in matrix composition and conditions influencing a sample in the ion source are considered by means of introducing two fitting parameters-atomization and ionization "temperatures"-into these exponents. Experiments carried out with the help of mass-spectrometers with spark and laser ion sources have corroborated the validity of the suggested quasi-equilibrium model and shown the possibility of its application for the improvement of the accuracy of analysis without use of standards as well as for checking the stability of experimental conditions in the process of analysis with standard samples. 相似文献
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996.
This paper is devoted to the study of the global dynamical properties of a two-dimensional noninvertible map, with a denominator which can vanish, obtained by applying Bairstow's method to a cubic polynomial. It is shown that the complicated structure of the basins of attraction of the fixed points is due to the existence of singularities such as sets of nondefinition, focal points, and prefocal curves, which are specific to maps with a vanishing denominator, and have been recently introduced in the literature. Some global bifurcations that change the qualitative structure of the basin boundaries, are explained in terms of contacts among these singularities. The techniques used in this paper put in evidence some new dynamic behaviors and bifurcations, which are peculiar of maps with denominator; hence they can be applied to the analysis of other classes of maps coming from iterative algorithms (based on Newton's method, or others). (c) 1999 American Institute of Physics. 相似文献
997.
Barelko VV Pomogailo AD Dzhardimalieva GI Evstratova SI Rozenberg AS Uflyand IE 《Chaos (Woodbury, N.Y.)》1999,9(2):342-347
The phenomenon of autowave (frontal) solid phase polymerization of metal-containing monomers based on metal-acrylamide complexes is considered. The comparison of the features of autowave processes realized in both the single-component matrices of the monomer and the matrices filled by the fiberglass materials is performed. The unstable regimes of the polymerization wave as well as the conditions for the stabilization of the flat front in the filled matrices are described. The peculiarities of the frontal regimes in the three- and two-dimensional media are studied. Some possibilities for using of autowave polymerization in the fabrication of the polymer-fiberglass composites and composition prepregs are discussed. (c) 1999 American Institute of Physics. 相似文献
998.
The interaction between two one-dimensional quadratic solitons has been investigated experimentally in lithium niobate planar waveguides for both parallel- and crossing-launched solitons. 相似文献
999.
振荡反应中的反馈机制 总被引:1,自引:0,他引:1
发生持续的化学振荡反应的条件,除了敝开系统、远离平衡外,还必须具有非线性反馈机制。弄清楚振荡反应系统的反馈机制,对于弄清楚反应过程的热力学行为和动力学规律是 相似文献
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