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Mary Beth Stearns 《Journal of magnetism and magnetic materials》1977,5(2):167-171
Values of the electron spin-polarization and their proportionality to bulk moments are easily explained by realizing that they are due to the itinerant d-like electrons. The proportionality of the tunneling current of superconductors and ferromagnets to the three-dimensional density-of-states is seen to occur naturally in the independent particle model. In contrast to tunneling, photoelectrons are dominated by localized electrons; these are also seen to be in agreement with calculated band structure. 相似文献
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Ohne Zusammenfassung 相似文献
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We use a simple example (the projective plane on seven points) to give an introductory survey on the problems and methods in finite geometries — an area of mathematics related to geometry, combinatorial theory, algebra, group theory and number theory as well as to applied mathematics (e.g., coding theory, information theory, statistical design of experiments, tomography, cryptography, etc.). As this list already indicates, finite geometries is — both from the point of view of pure mathematics and from that of applications related to computer science and communication engineering — one of the most interesting and active fields of mathematics. It is the aim of this paper to introduce the nonspecialist to some of these aspects.To Professor Günter Pickert on the occasion of his 65th birthday 相似文献
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Nielsen RD Hustedt EJ Beth AH Robinson BH 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2004,170(2):277-371
The Bloch equation containing a Zeeman modulation field is solved analytically by treating the Zeeman modulation frequency as a perturbation. The absorption and dispersion signals at both 0 degrees and 90 degrees modulation phase are obtained. The solutions are valid to first order in the modulation frequency, but are otherwise valid for any value of modulation amplitude or microwave amplitude. A first order treatment of modulation frequency is shown to be a valid approximation over a wide range of typical experimental EPR conditions. The solutions derived from the Bloch equation suggest that the effect of over-modulation on first and second harmonic EPR spectra can be formulated as a mathematical filter that smoothes and broadens the under-modulated signal. The only adjustable filter parameter is a width that is equivalent to the applied peak-to-peak modulation amplitude. The true spin-spin and spin-lattice relaxation rates are completely determined from the under-modulated spectrum. The filters derived from the analytic solutions of the Bloch equation in the linear limit of modulation frequency are tested against numerical solutions of the Bloch equation that are valid for any modulation frequency to show their applicability. The filters are further tested using experimental EPR spectra. Experimental under-modulated spectra are mathematically filtered and compared with the experimental over-modulated spectra. The application of modulation filters to STEPR spectra is explored and limitations are discussed. 相似文献
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Dr. Thomas Beth 《Journal of Geometry》1980,15(1):89-92
The dimension of the F-row spaces of the incidence matrices of all affine planes AG(2,n) is determined. The proof presented here gives a unified method for the cases when charF is or is not a divisor of n. 相似文献