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A method to determine the strain tensor and local lattice rotation with dark-field X-ray microscopy is presented. Using a set of at least three non-coplanar symmetry-equivalent Bragg reflections, the illuminated volume of the sample can be kept constant for all reflections, facilitating easy registration of the measured lattice variations. This requires an oblique diffraction geometry, the diffraction plane is neither horizontal nor vertical. We derive a closed analytical expression that allows determination of the strain and lattice rotation from the deviation of experimental observables ( goniometer angles) from their nominal values for an unstrained lattice.
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http://dx.doi.org/10.1107/S1600576725005862 | DOI Listing |
J Acoust Soc Am
August 2025
Mechanical Engineering, Indian Institute of Science, Bengaluru, Karnataka 560012, India.
This study investigates the sound transmission characteristics of an unbaffled simply supported plate excited by a plane wave incident at an arbitrary angle. The pressure jump across the unbaffled plate results from the combined effects of pure diffraction and pure radiation. In pure diffraction, the plane wave interacts with a rigid unbaffled plate, while in pure radiation, the pressure jump arises from the flexural vibrations of the plate.
View Article and Find Full Text PDFIt is known that the oblique helicoidal cholesteric structure ( ), which is formed in an alternating electrical field applied to the chiral nematic phase ( ) at temperatures above the chiral twist-bend nematic phase ( ∗), can show selective Bragg reflection in the visible range of the spectrum. In this work, we study the effects of alternating electric field at different frequencies, as well as UV irradiation on the Bragg reflection of the structure of the ∗-forming mixture containing a light-sensitive chiral azo-compound. It has been found that the structure shows two sequential states in the tuning of selective Bragg reflection at high and low electrical fields.
View Article and Find Full Text PDFA method to determine the strain tensor and local lattice rotation with dark-field X-ray microscopy is presented. Using a set of at least three non-coplanar symmetry-equivalent Bragg reflections, the illuminated volume of the sample can be kept constant for all reflections, facilitating easy registration of the measured lattice variations. This requires an oblique diffraction geometry, the diffraction plane is neither horizontal nor vertical.
View Article and Find Full Text PDFSensors (Basel)
July 2025
Key Laboratory for Micro and Nanophotonic Structures (Ministry of Education, China), Department of Optical Science and Engineering, School of Information Science and Engineering, Fudan University, Shanghai 200433, China.
This paper reports on the high performance of a thick-waveguide guided mode resonance (GMR) sensor. Theoretical calculations revealed that when light incidents on the grating and excites the negative first-order diffraction order, by increasing the waveguide thickness, both a high sensitivity and high figure of merit (FOM) can be obtained. Experimentally, we achieved a sensitivity of 1255.
View Article and Find Full Text PDFPurpose: To evaluate tolerance to simulated astigmatism on distance visual acuity in pseudophakic eyes implanted with an extended depth of focus (EDOF) diffractive intraocular lens (IOL) with violet light filter.
Methods: This prospective observational study enrolled consecutive patients who underwent cataract surgery with violet light-filtering diffractive EDOF IOL implantation. Cylinder defocus was induced with plus cylinder lenses from +0.