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Conventional metal-tip-based laser-driven electron sources are normally constrained by a trade-off between energy spread and pulse width due to optical-field-induced free electron acceleration. This makes it challenging to surpass the current state-of-the-art, which exhibits energy spreads exceeding 1 eV and pulse durations of hundreds of femtoseconds. Here we report an unconventional delayed emission from a one-dimensional carbon-nanotube-based electron source. By utilizing a special pump-probe approach, we apply 7-fs laser pulses to the carbon-nanotube emitters and observe free electron emission tens of femtoseconds after the pulse. This delayed emission results in a substantially reduced energy spread of approximately 0.3 eV and an electron pulse width of about 13 fs. Through time-dependent density functional theory calculations, we find that the delayed emission is driven by the interplay of collective oscillations and electron-electron interactions. Our results may provide a promising technology for developing cutting-edge ultrafast electron sources.
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http://dx.doi.org/10.1038/s41563-025-02279-7 | DOI Listing |
Food Chem X
August 2025
Department of Toxicology, İstanbul Aydın University, P.O. Box 65, 00014 Istanbul, Turkey.
This study investigated the effect of refining time on the physicochemical and functional properties of anhydrous cream prepared from a palm-sunflower oil blend using a stirred ball mill. Refining was performed for 0-300 min, and its impact on particle size distribution, rheology, oxidative stability, and thermal behavior was assessed. The target particle fineness (D90 ≤ 30 μm) was achieved at approximately 180 min, with negligible reduction thereafter.
View Article and Find Full Text PDFIndoor Air
January 2025
National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Background/objectives: Respiratory viruses circulate year-round and can spread indoors via inhalation of airborne particles. Effective ventilation and filtration may reduce transmission, particularly in school settings where children and staff spend significant time. This study examines the impact of indoor air quality (IAQ) and ventilation in schools on respiratory virus detection.
View Article and Find Full Text PDFUnlabelled: Passive Acoustic Mapping (PAM) is rapidly emerging as a ubiquitous tool for real-time localization and monitoring of therapeutic ultrasound treatments involving cavitation in the context of safety or efficacy. The ability of PAM to spatially quantify and resolve cavitation activity offers a unique opportunity to correlate the energy of cavitation phenomena with locally observed bioeffects.
Objective: We aim to develop methods of measuring and reporting spatio-temporally varying cavitation energies that are energy-preserving, device-independent, and adequately normalized to the volume of tissue being affected by the reported cavitation activity.
Rapid Commun Mass Spectrom
September 2025
Département Médicaments et Technologies pour la Santé (DMTS), MetaboHUB, Université Paris-Saclay, CEA, INRAE, Gif sur Yvette, France.
Rationale: Electrospray (ESI), the most popular desorption/ionization technique used in mass spectrometry-based metabolomics, generates both protonated and deprotonated molecules, as well as adduct ions, sodium being the most frequent monoatomic cation entering their composition. With the spread and generalization of untargeted data-dependent and independent tandem mass spectrometry experiments, considering product ion spectra of sodium-containing entities appears relevant to complement fragmentation information of their protonated and deprotonated counterparts.
Methods: Solutions of pure standards, mainly amino and organic acids, were prepared at 1 μg/mL and injected either by direct infusion or by flow-injection prior to ESI-MS/MS analysis.
Langmuir
September 2025
SERB Sponsered Microfluidics Laboratory, Department of Mechanical Engineering, Jadavpur University, Kolkata, West Bengal 700032, India.
This study investigates the dynamic behavior of water droplets impacting a superhydrophobic surface (SHS) at low Weber numbers ( < 17). SHS is fabricated by a chemical coating process on magnesium AZ31 alloy. The surfaces exhibit a Cassie-Baxter wetting state, showing a contact angle of approximately 155°on the surfaces.
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