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We present an experimental demonstration of ultrafast electron diffraction (UED) with THz-driven electron bunch compression and time-stamping that enables UED probes with improved temporal resolution. Through THz-driven longitudinal bunch compression, a compression factor of approximately four is achieved. Moreover, the time-of-arrival jitter between the compressed electron bunch and a pump laser pulse is suppressed by a factor of three. Simultaneously, the THz interaction imparts a transverse spatiotemporal correlation on the electron distribution, which we utilize to further enhance the precision of time-resolved UED measurements. We use this technique to probe single-crystal gold nanofilms and reveal transient oscillations in the THz near fields with a temporal resolution down to 50 fs. These oscillations were previously beyond reach in the absence of THz compression and time-stamping.
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http://dx.doi.org/10.1063/4.0000230 | DOI Listing |
IEEE Trans Pattern Anal Mach Intell
September 2025
Transformers have been successfully applied in the field of video-based 3D human pose estimation. However, the high computational costs of these video pose transformers (VPTs) make them impractical on resource-constrained devices. In this paper, we present a hierarchical plug-and-play pruning-and-recovering framework, called Hierarchical Hourglass Tokenizer (HOT), for efficient transformer-based 3D human pose estimation from videos.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States.
Coherent electron spin states within paramagnetic molecules hold significant potential for microscopic quantum sensing. However, all-optical coherence measurements amenable to high spatial and temporal resolution under ambient conditions remain a significant challenge. Here we conduct room-temperature, picosecond time-resolved Faraday ellipticity/rotation (TRFE/R) measurements of the electron spin decoherence time in [IrBr].
View Article and Find Full Text PDFEnviron Monit Assess
September 2025
Department of Water Resources Study and Research, Water Research Institute, Tehran, Iran.
Small glaciers situated in high mountainous areas are experiencing notable declines, characterized by unprecedented rates of ice loss in recent years. This study investigates the recent changes in surface elevation and mass loss occurring between 2010 and 2023 within the Alamkouh Glacier over three subperiods, one of the biggest glaciers in Iran and the Middle East. These assessments are derived from a combination of high-resolution LiDAR data in 2010 (with a spatial resolution of 20 cm) and multi-temporal surveys conducted using unmanned aerial vehicles (UAVs) in 2018, 2020, and 2023 (with spatial resolutions varied from 10 to 20 cm).
View Article and Find Full Text PDFJ Synchrotron Radiat
November 2025
Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA.
Nano-laminography combines the penetrating power of hard X-rays with a tilted rotational geometry to deliver high-resolution, three-dimensional images of laterally extended, flat specimens that are otherwise incompatible with, or difficult to image using, conventional nano-tomography. In this work, we demonstrate a full-field, X-ray nano-laminography system implemented with the transmission X-ray microscope at beamline 32-ID of the upgraded Advanced Photon Source at Argonne National Laboratory, USA. By rotating the sample around an axis inclined by 20° to the incident beam, the technique minimizes the long optical path lengths that would otherwise generate excessive artifacts when planar samples are imaged edge-on.
View Article and Find Full Text PDFJ Anal At Spectrom
September 2025
Department of Environmental Systems Science, ETH Zurich Universitätstrasse 16 8092 Zurich Switzerland.
Plastic pollution in marine environments poses ecological risks, in part because plastic debris can release hazardous substances, such as metal-based additives. While microplastics have received considerable attention as vectors of contaminants, less is known about larger macroplastics and their role in the spatial and temporal redistribution of substances. In this study, pristine, store-bought plastic items and macroplastics recovered from the North Pacific Subtropical Gyre (NPSG) were analysed using Fourier-Transform Infrared Spectroscopy (FTIR) to identify polymer types, and bulk acid digestion followed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for total metal quantification.
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