1,721,014 research outputs found
Pyramidal metamaterial-based absorbers for mode damping inside resonating structures
No full textMany resonant structures in the microwave region need damping of parasitic or higher order modes in order to optimise their performance. In cavities or other systems operating in accelerating structures, for example, the mitigation of spurious resonance effects is indispensable to achieve high quality particle beams. We present here a parametric study on the absorption properties of a multilayered metamaterial having the shape of a truncated pyramid to be used as light, small volume damper in a microwave cavity. Full wave simulations have been performed for a single absorber varying its size and number of layers and for a linear array changing the distance between the single elements. A case study is proposed, where a single pyramid is inserted in a real pillbox cavity. Measurements of the cavity response without and with the metamaterial absorber are presented and compared with numerical results
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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