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991.
992.
993.
994.
E. Lippelt P. Birrer F. N. Gygax B. Hitti A. Schenck M. Weber 《Hyperfine Interactions》1991,64(1-4):477-487
The angular dependence of the muon Knight shift,K
μ, and the muon relaxation rate in Bi at 11 K were measured in external magnetic fields up to 1 T. BothK
μ and the second moment,M
2, are field dependent and involveP
4
0(cos θ) andP
4
3(cos θ) terms in the angular dependence. The Knight shift behaviour is discussed in terms of the dipole-dipole interaction
and the de Haas-van Alphen effect, a consistent interpretation was not achieved in either case. The field dependence ofM
2 is in complete contrast to the second moment calculations and points to a field dependent redistribution of the charge distribution
around the interstitial site. 相似文献
995.
A new class of Hamiltonian dynamical systems with two degrees of freedom and kinetic energy of the form T = c1|p1| + c2|p2| (called “pseudo-billiards”) is studied. For any kind of interaction, the canonical equations can always be integrated on sequential time intervals; i.e. in principle all the trajectories can be found explicitly.
Depending on the potential, a dynamical system of this class can either be completely integrable or behave just as a usual non-integrable Hamiltonian system with two degrees of freedom: in its phase space there exist invariant tori, stochastic layers, domains of global chaos, etc. Pseudo-billiard models of both the types are considered.
If a potential of a pseudo-billiard system has critical points (equilibria), then trajectories close to these points (“loops”) can exist; they can be treated as images of self-localized objects with finite duration. Such a model (with quartic potential) is also studied. 相似文献
996.
A demonstration is proposed of the nonstationary diffusion of sodium from a melt of its salt in two-electrode light indicators of a discharge in the cases of electric fields accelerating and damping the motion of ions.Mordovinian Pedagogical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 98–102, May, 1992. 相似文献
997.
Summary If hydrogen is diffused electrolytically in a metal, it subsequently escapes out if the metal is left to itself. However this
hydrogen-treated metal does not totally regain the original magnitudes of its various physical properties,e. g., thermo e.m.f., electrical resistivity, elastic modulii etc. This effect has also been observed in the second-order elastic
effect (the Poynting effect) in nickel and two varieties of steel. Measurements were carried out first before hydrogen diffusion.
The samples were electrolytically diffused with hydrogen and the left to themselves for a few days and the measurements were
repeated. The changed values of the coefficient of Poynting effect are discussed in terms of the dislocations created by in-and
out-going hydrogen.
Now retired 相似文献
998.
A. S. Il'inskii S. V. Trubnikov N. A. Fedoseeva 《Computational Mathematics and Modeling》1994,5(3):195-202
Translated from Matematicheskie Modeli i Optimizatsiya Vychislitel'nykh Algoritmov, pp. 131–143, 1993. 相似文献
999.
A. K. Shahani N. Korve K. P. Jones D. J. Paynton 《The Journal of the Operational Research Society》1994,45(8):916-926
Asthma is one of the major chronic diseases in many countries. At present there is no cure for asthma, but medical advances can help to reduce the chances of attacks of the condition. Efficient care for asthma involves complexity, uncertainty, variability and the use of scarce resources, and these are the same conditions that indicate a possible use for the modelling approach of operational research. This paper is concerned with a pilot model that was developed through joint work by medical professionals and operational researchers. The development of the model is explained and illustrative results indicate the potential value of the modelling approach for the care of asthma in the community. 相似文献
1000.
We investigate the possibility of approximating a function on a compact setK of the complex plane in such a way that the rate of approximation is almost optimal onK, and the rate inside the interior ofK is faster than on the whole ofK. We show that ifK has an external angle smaller than π at some point zo∈δK, then geometric convergence insideK is possible only for functions that are analytic at zo. We also consider the possibility of approximation rates of the form exp(?cn β), for approximation insideK, where β is related to the largest external angle ofK. It is also shown that no matter how slowly the sequence {γ n } tends to zero, there is aK and a Lip β, β<1, functionf such that approximation insideK cannot have order {γ n }. 相似文献