Results 71 to 80 of about 99,715 (244)
Fresnel zone plate forms images at wavelengths below 1000 angstroms [PDF]
, 1965 Fresnel zone plate with openings replacing the usual transparent rings produces images in a vacuum ultraviolet.
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Technologies for Near-Field Focused Microwave Antennas
International Journal of Antennas and Propagation, 2017 This paper provides a review spanning different technologies used to implement near-field focused antennas at the microwave frequency band up to a few tens of GHz: arrays of microstrip patches and printed dipoles, arrays of dielectric resonator antennas,
Paolo Nepa +3 more
doaj +1 more source
Advanced Science, EarlyView.Cell‐sized high‐frequency ultrasound using a lithium niobate transducer, previously ignored in reactive oxygen species (ROS) production, generated intracellular ROS at frequencies higher than conventionally used. The intracellular generation of ROS by cell‐sized high‐frequency ultrasound revealed in this study is expected to be applied to innovative ...
Kotaro Fujishiro +4 more
wiley +1 more source
High efficiency and low absorption Fresnel compound zone plates for hard X-ray focusing
, 2005 Circular and linear zone plates have been fabricated on the surface of silicon crystals for the energy of 8 keV by electron beam lithography and deep ion plasma etching methods.
Aristov, V. +11 more
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Optimization of modified volume Fresnel zone plates
Journal of the Optical Society of America A, 2009 Modified volume Fresnel zone plates (MVFZPs) fabricated with laser direct writing were optimized for higher diffraction efficiencies. The Fresnel radii in each layer of a volume zone plate were iteratively adjusted by a simulation-based direct search optimization.
Srisungsitthisunti, Pornsak +2 more
openaire +5 more sources
Advanced Science, EarlyView.A programmable 2048‐element circular ultrasound array combined with a compact acoustic lens produces a thin “sound sheet” over a large field of view, and records echoes with wide angular diversity across the ring aperture. Coherence‐enhanced beamforming converts full‐matrix data into high‐contrast tomographic slices, delivering near‐diffraction‐limited
Qiu‐De Zhang +11 more
wiley +1 more source
The self-focusing Fresnel-Dammann grating and the Fresnel binary CGH for compact 2-D light spot array generation [PDF]
, 1993 The authors have described the design and demonstrated the performance of two types of lensless array generator. The Self-focusing Fresnel-Dammann grating (SFD), and the Fresnel hologram.
Carey, C.D. +3 more
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BeSense: Leveraging WiFi Channel Data and Computational Intelligence for Behavior Analysis
, 2020 The ever evolving informatics technology has gradually bounded human and computer in a compact way. Understanding user behavior becomes a key enabler in many fields such as sedentary-related healthcare, human-computer interaction (HCI) and affective ...
Gu, Yu +3 more
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Analysis of 3D-printed metal for rapid-prototyped reflective terahertz optics [PDF]
, 2016 We explore the potential of 3D metal printing to realize complex conductive terahertz devices. Factors impacting performance such as printing resolution, surface roughness, oxidation, and material loss are investigated via analytical, numerical, and ...
Abbott, Derek +5 more
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M-Bonacci Zone Plates for Ultrasound Focusing
Sensors, 2019 In this work, we present a thorough analysis on M-bonacci zone plates for ultrasound focusing applications. These planar lenses are capable of providing bifocal focusing profiles with equal intensity in both foci and become very appealing for a wide ...
Sergio Pérez-López +2 more
doaj +1 more source