Radiography of low-contrast features in high-density materials evolving on a nanosecond timescale requires a bright photon source in the tens of keV range with high temporal and spatial resolution. One application for sources in this category is the study of dynamic material strength in samples compressed to Mbar pressures at the National Ignition Facility, high-resolution measurements of plastic deformation under conditions relevant to meteor impacts, geophysics, armor development, and inertial confinement fusion. We present radiographic data and the modulation transfer function (MTF) analysis of a multi-component test object probed at ∼100 keV effective backlighter energy using a 5 μm-thin dysprosium foil driven by the NIF Advanced Radiographic Capability (ARC) short-pulse laser (∼2 kJ, 10 ps). The thin edge of the foil acts as a bright line-projection source of hard x rays, which images the test object at 13.2× magnification into a filtered and shielded image plate detector stack. The system demonstrates a superior contrast of shallow (5 μm amplitude) sinusoidal ripples on gold samples up to 90 μm thick as well as enhanced spatial and temporal resolution using only a small fraction of the laser energy compared to an existing long-pulse-driven backlighter used routinely at the NIF for dynamic strength experiments.
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http://dx.doi.org/10.1063/5.0043783 | DOI Listing |
Sci Rep
December 2024
Department of Civil Engineering, Tianjin University, Tianjin, 300072, China.
Taking the conducted model test by authors as the research object, this paper first carries out detailed numerical analysis and verifies the reliability of the established model. Furthermore, the test phenomenon is explained based on numerical analysis, while parameter analysis is carried out, which mainly includes soil deformation between piles and soil deformation inside and outside excavation. The research results show that when the inclination angle of the piles is small (such as 10°), all or most of the soil (the range of the pile top to 0.
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December 2024
College of Energy Engineering, Xi'an University of Science and Technology, Xi'an, 710054, China.
Affected by weakening effect of water in the goaf, the bearing capacity of coal pillar reduced, and coal pillar rock burst is prone to occur, which is a serious threat to mine safety in production. In order to study the equivalent width and stability of coal pillar in water-rich coal seam, taking the section coal pillar of a working face as the research object, combined with laboratory test, theoretical analysis, simulation and engineering practice, the stress, elastic core area width, damage degree and energy accumulation of 36 m water-immersed coal pillar and 26 m, 28 m, 30 m, 32 m, 36 m unimmersed coal pillars are analyzed. The research results show that: (1) The reasonable width of coal pillar under flooded and unflooded conditions is 36.
View Article and Find Full Text PDFPsychol Res
December 2024
Brain and Cognition, KU Leuven, Leuven, Belgium.
Researchers in numerical cognition have extensively studied the number sense-the innate human ability to extract numerical information from the environment quickly and effortlessly. Much of this research, however, uses abstract stimuli (e.g.
View Article and Find Full Text PDFEur Eat Disord Rev
December 2024
Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
Objective: We aimed to examine the cognitive profile in adolescents with anorexia nervosa (AN) and its association with traits of autism spectrum disorder (ASD) and ADHD. In addition, resemblance in the cognitive profile between youths with AN and their parents was explored.
Methods: Adolescent females with acute AN (n = 20) and a healthy comparison group (n = 28) completed neuropsychological tasks of set-shifting (Trail making test, Wisconsin Card Sorting Test) and central coherence (Rey Complex Figures Task, Group Embedded Figures Test, object assembly subtest).
Adv Sci (Weinh)
December 2024
Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore.
Spatially selective imaging (SSI) involves sampling a group of pixels from different positions on an encoded object to display a decoded image. Here, SSI is achieved by using off-axis cylindrical Fresnel lens arrays to decode multiple images from an encoded print of structural color pixels. Each image is optically retrieved by separately placing different "keys" (arrays of lenses in different pseudorandom configurations) over the same encoded print, and then each image is digitally reconstructed for visualization.
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