3 resultados para pulse-shaping

em Greenwich Academic Literature Archive - UK


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Methods for serial generation of droplets from a liquid jet are shortly reviewed. A method of liquid metal droplet generation based on AC high frequency magnetic field is considered in detail. Numerical model for direct simulation of the time dependent droplet generation process is presented. Computed examples demonstrate the liquid silicon droplet formation for the cases of 500-1500 μm diameter.

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This paper explores the significance of trails within local government cultural strategies by presenting the results of an audit of 1000 trails, content analysis of local cultural strategies and a series of interviews with local government cultural officers. It highlights the growing sophistication of trails as flexible and multi-faceted products promising an array of social, environmental, cultural and economic benefits. However, key issues emerge as challenges for local government cultural officers. These include the need for a realistic assessment of the relative importance of competing rationales, the design of methodologies to enable evidence-based policy making and more effective engagement with commercial organisations.

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Pulse design is investigated for time-reversal (TR) imaging as applied to ultrawideband (UWB) breast cancer detection. Earlier it has been shown that a suitably-designed UWB pulse may help to improve imaging performance for a single-tumor breast phantom with predetermined lesion properties. The current work considers the following more general and practical situations: presence of multiple malignancies with unknown tumor size and dielectric properties. Four pulse selection criteria are proposed with each focusing on one of the following aspects: eliminating signal clutter generated by tissue inhomogeneities, canceling mutual interference among tumors, improving image resolution, and suppressing artifacts created by sidelobe of the target response. By applying the proposed criteria, the shape parameters of UWB waveforms with desirable characteristics are identified through search of all the possible pulses. Simulation example using a numerical breast phantom, comprised of two tumors and structured clutter distribution, demonstrates the effectiveness of the proposed approach. Specifically, a tradeoff between the image resolution and signal-to-clutter contrast (SCC) is observed in terms of selection of the excitation waveforms.