A high-energy resolution post-column spectrometer for the purpose of electron energy loss spectroscopy (EELS) and energy-filtered TEM in combination with a monochromated (S)TEM is presented. The prism aberrations were corrected up to fourth order using multipole elements improving the electron optical energy resolution and increasing the acceptance of the spectrometer for a combination of object area and collection angles. Electronics supplying the prism, drift tube, high-tension reference and critical lenses have been newly designed such that, in combination with the new electron optics, a sub-50 meV energy resolution has been realized, a 10-fold improvement over past post-column spectrometer designs. The first system has been installed on a 200 kV monochromated TEM at the Delft University of Technology. Total system energy resolution of sub-100 meV has been demonstrated. For a 1s exposure the resolution degraded to 110 meV as a result of noise. No further degradation in energy resolution was measured for exposures up to 1 min at 120 kV. Spectral resolution measurements, performed on the pi* peak of the BN K-edge, demonstrated a 350 meV (FWHM) peak width at 200 kV. This measure is predominantly determined by the natural line width of the BN K-edge.
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http://dx.doi.org/10.1016/S0304-3991(03)00102-5 | DOI Listing |
Chem Commun (Camb)
January 2025
Institute of Inorganic Chemistry, Czech Academy of Sciences, 250 68 Husinec-Řež, Czech Republic.
Co-pyrolysis reactions of BBr with SBr at 350 °C yielded the brominated thiaboranes -SBBr (1), -1-SBBr (2) and -SBBr (3), confirmed by high-resolution mass spectrometry, experimental and computational B NMR spectroscopy. The strong Br(σ-hole)⋯Br(ring) attraction has been the decisive energy contribution in the crystal of 1.
View Article and Find Full Text PDFSmall Methods
January 2025
College of Physics and Energy, Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fujian Normal University, Fuzhou, 350117, China.
The Solid Electrolyte Interphase (SEI) is a nanoscale thickness passivation layer that forms as a product of electrolyte decomposition through a combination of chemical and electrochemical reactions in the cell and evolves over time with charge/discharge cycling. The formation and stability of SEI directly determine the fundamental properties of the battery such as first coulombic efficiency (FCE), energy/power density, storage life, cycle life, and safety. The dynamic nature of SEI along with the presence of spatially inhomogeneous organic and inorganic components in SEI encompassing crystalline, amorphous, and polymeric nature distributed across the electrolyte to the electrolyte-electrode interface, highlights the need for advanced in situ/operando techniques to understand the formation and structure of these materials in creating a stable interface in real-world operating conditions.
View Article and Find Full Text PDFAnn Bot
January 2025
Research Centre for Ecosystem Resilience, Botanic Gardens of Sydney, Sydney, NSW, 2000, Australia.
The importance of conserving plant genetic diversity has been recognised since the 1980's, but genetic research tools for improving conservation remain largely absent from standard planning. Using an Australian case study framework of the New South Wales Government's Saving our Species program, we outline the costs and benefits associated with conducting genomic analysis within a conservation strategy to inform for example, taxonomic resolution, targeted monitoring, translocations and ex situ collections. Despite a reported sentiment that costs are prohibitive, our study identified that where genetics reports have been provided (32 to date), the cost of genetic sampling, analysis and advice is less than 10% of the total Government investment (SoS program) and will continue decreasing proportionally throughout the years as other management occurs.
View Article and Find Full Text PDFJ Agric Food Chem
January 2025
Guangdong Key Laboratory of Environmental Resources Utilization and Protection, State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
Poly- and perfluoroalkyl substances (PFASs) are a large class of fluorinated chemicals used in various industrial and agrochemical products such as fluorinated benzoylurea (FBU) pesticides. Initiated from an incidental and preliminary finding of three high-abundance FBUs in fish, this study implemented nontarget analysis and characterization for FBUs together with their analogues and transformation products (TPs) in fish using liquid chromatography, high-resolution mass spectrometry, and chemical species-specific algorithms. A total of 23 FBU-relevant compounds were found and tentatively/accurately elucidated with structures, including 18 PFASs and 5 non-PFAS compounds, of which 4 were original FBUs, 8 were FBU analogues, and 11 were FBU-TPs.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Quantum-Si, Guilford, CT, USA.
Single-molecule fluorescence resonance energy transfer (smFRET) is a powerful technique for studying the structural dynamics of protein molecules or detecting interactions between protein molecules in real time. Due to the high sensitivity in spatial and temporal resolution, smFRET can decipher sub-populations within heterogeneous native state conformations, which are generally lost in traditional measurements due to ensemble averaging. In addition, the single-molecule reconstitution allows protein molecules to be observed for an extensive period of time and can recapitulate the geometry of the cellular environment to retain biological function.
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