A five-channel microwave interferometer with high temporal resolution and high phase resolution has been developed for measuring electron density profiles and fluctuations on the Sino-UNIted Spherical Tokamak. A correction algorithm, based on the low signal amplitude detection, is proposed to eliminate the fringe jump errors. The correction algorithm achieves an accuracy of 92%. The density profile is reconstructed through the Park-matrix method, with the geometry of magnetic surfaces calculated by the equilibrium fitting. The reconstructed density profiles for discharges with supersonic molecular beam injection are in good agreement with the results of another 94 GHz single-channel horizontal interferometer and the Langmuir probes. The temporal resolution of the system is 0.5 µs and the line-integrated electron density resolution is 1 × 10 m, which benefits from the single sideband modulation technique. Therefore, the multichannel interferometer system is capable of studying the details of the high-frequency (up to 200 kHz) density fluctuation such as that in the minor disruption event.
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http://dx.doi.org/10.1063/5.0043667 | DOI Listing |
J Phys Chem Lett
January 2025
Robinson Research Institute, Faculty of Engineering, Victoria University of Wellington, Wellington 6012, New Zealand.
We demonstrate a high-performance ultrafast broadband time-resolved photoluminescence (TRPL) system based on the transient grating photoluminescence spectroscopy (TGPLS) technique. The core of the system is a Kerr effect-induced transient grating (TG) optical gate driven by high repetition rate ultrashort laser pulses at 1030 nm with micro-Joule pulse energy. Satisfying the demands of spectroscopy applications, the setup achieves high sensitivity, rapid data acquisition, ultrafast time resolution, and a wide spectral window from ultraviolet to near-infrared.
View Article and Find Full Text PDFSci Rep
January 2025
Nagoya University, Furo, Chikusa, Nagoya, Aichi, 464-8601, Japan.
Alkali antimonide semiconductor photocathodes are promising candidates for high-brightness electron sources for advanced accelerators, including free-electron lasers (FEL), due to their high quantum efficiency (QE), low emittance, and high temporal resolution. Two challenges with these photocathodes are (1) the lack of a universal deposition recipe to achieve crystal stoichiometries and (2) their high susceptibility to vacuum contamination, which restricts their operation pressure to ultrahigh vacuums and leads to a short lifetime and low extraction charge. To resolve these issues, it is essential to understand the elemental compositions of deposited photocathodes and correlate them to robustness.
View Article and Find Full Text PDFSci Data
January 2025
Zhejiang Academy of Surveying and Mapping, Hangzhou, 310001, China.
Solar-induced chlorophyll fluorescence (SIF) is an indicator of vegetation photosynthesis, and multiple satellite SIF products have been generated in recent years. However, current SIF products are limited for applications toward vegetation photosynthesis monitoring because of low spatial resolution or spatial discontinuity. This study uses a spatial downscaling method to obtain a redistribution of the original TROPOspheric Monitoring Instrument (TROPOMI) SIF (OSIF).
View Article and Find Full Text PDFSci Total Environ
January 2025
Department of Forest Sciences, Faculty of Agricultural and Environmental Sciences, Universidad de La Frontera, Temuco, Chile.
Peatlands are key ecosystems for global climate regulation because they provide the most efficient carbon sink on the planet. Despite this, they have been widely degraded by various anthropogenic disturbances, causing imbalances in their ecological functioning. A more recent type of disturbance corresponds to the commercial extraction of Sphagnum mosses, which has been carried out in temperate peatlands distributed in Australasia and Patagonia.
View Article and Find Full Text PDFSci Prog
January 2025
Department of Otolaryngology, Fengdu County People's Hospital, Fengdu County, Chongqing, China.
Objective: This study aims to analyze anatomical parameters of the transmission route of sigmoid sinus tinnitus (SST) to explore its mechanism and speculate on possible responsible anatomical abnormalities.
Methods: Clinical data were retrospectively collected from SST and sigmoid sinus wall dehiscence (SSWD) patients suggested by temporal bone high resolution computed tomography (HRCT), with and without tinnitus, at the First Affiliated Hospital of Chongqing Medical University from January 2015 to August 2022. Patients were divided into SSWD tinnitus ( = 61), and non-tinnitus ( = 60) groups based on HRCT features.
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