Languages Eng1i sh. Country of Origin: United States. Country of Publication: United States Document Type: JOURNAL ART ICLE Most documents available from AIAA Technical Library Journa1 Announcement: IA A8420 The efficiency of the mth-harmonic electron-cyclotron- maser interaction for a TE(mnl) gyrotron oscillator is compared with the r(m - 1) th harmonic peniotronlike interaction. Identical cavities and electron beams are used. Start oscillation conditions from weak-field linear theory are given, as well as optimized nonlinear efficiencies. The peniotronlike interaction leads to optimized efficiencies of 65 percent or less, while those for the electron-cyclotron-maser interaction are limited to 25 percent or less in the cases studied. (Author) Source of Abstract (Subfile): AIAA/TIS Descriptors: *CYCLOTRON RESONANCE DEVICES; *ENERGY CONVERSION EFFICIENCY; *FIELD MODE THEORY; *FREQUENCY STABILITY; *MASER OUTPUTS; *MICROWAVE OSCILLATORS; CAVITY RESONATORS; MODAL RESPONSE; POWER CONDITIONING; SYSTEMS STABILITY Subject Classifications 7536 Lasers & Masers (1975-) Limitations of the cubical block model of man in calculating SAR distributions. (Specific Absorption Rate). MASSOUDI, H.; DURNEY, C. H.; ISKANDER, M. F. (Utah, University, Salt Lake City, LJT) IEEE Transactions on Microwave Theory and Techniques (ISSN 0018-9480), vol. MTT-32, Aug. 1984, p. 746-752. 12 Refs. Contract No.: F33615-79-C-0614 Lan guage: English. Country of Origin: United States. Country of Publication: Un ited States Document Type: JOURNAL ARTICLE Most documents available from AIAA Technical Library Journal Announcement: IAA8420 Block models of man which consist of a limited number of cubical cells are commonly used to predict the internal electromagnetic (EM) fields and specific absorption rate (SAR) distributions inside the human body. Numerical results, for these models, are obtained based on momentmethod solutions of the electric-field integral equation (EFIE) with a pulse function being used as the basis for expanding the unknown internal field. In this paper, the adequacy of the moment—method procedure, with pulse basis functions, is examined to determine SAR distributions in homogeneous models. Calculated results for the SAR distributions in some block models are presented, and the stability of the solutions is discussed. It is shown that, while the moment-method, using pulse basis functions, gives good values for whole—body average SAR, the convergence of the solutions for SAR distributions is questionable. A new technique for improving the spatial resolution of SAR distribution calculations using a different EFIE and Galerkin's method with linear basis functions and polyhedral mathematical cells is also described. (Author)
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