The first dedicated local electrode atom probes (LEAP [a trademark of Imago Scientific Instruments Corporation]) have been built and tested as commercial prototypes. Several key performance parameters have been markedly improved relative to conventional three-dimensional atom probe (3DAP) designs. The Imago LEAP can operate at a sustained data collection rate of 1 million atoms/minute. This is some 600 times faster than the next fastest atom probe and large images can be collected in less than 1 h that otherwise would take many days. The field of view of the Imago LEAP is about 40 times larger than conventional 3DAPs. This makes it possible to analyze regions that are about 100 nm diameter by 100 nm deep containing on the order of 50 to 100 million atoms with this instrument. Several example applications that illustrate the advantages of the LEAP for materials analysis are presented.
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http://dx.doi.org/10.1017/S1431927604040565 | DOI Listing |
J Chem Inf Model
December 2024
Dipartimento di Bioscienze, Università degli Studi di Milano, Milan 20133, Italy.
The computational study of ligand binding to a target protein provides mechanistic insight into the molecular determinants of this process and can improve the success rate of drug design. All-atom molecular dynamics (MD) simulations can be used to evaluate the binding free energy, typically by thermodynamic integration, and to probe binding mechanisms, including the description of protein conformational dynamics. The advantages of MD come at a high computational cost, which limits its use.
View Article and Find Full Text PDFTree Physiol
December 2024
Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå.
Isotopic pulse-labelling of photosynthate allows tracing of carbon (C) from tree canopies to belowground biota and calculations of its turnover in roots and recipient soil microorganisms. A high concentration of label is desirable, but is difficult to achieve in field studies of intact ecosystem patches with trees. Moreover, root systems of trees overlap considerably in most forests, which requires a large labelled area to minimize the impact of C allocated belowground by un-labelled trees.
View Article and Find Full Text PDFOrg Lett
December 2024
College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan 250014, China.
We herein report a photoredox N-S coupling reaction between dialkyl azodicarboxylates and thiols to access sulfenamide scaffolds. This reaction proceeds under mild, green, and operationally simple conditions, offering a broad scope of sulfenamides with high yields and excellent atom efficiency. Mechanistic investigations revealed this reaction followed a photoinitiated radical pathway in which iodide plays a crucial role as both a radical initiator and a single-electron reductant.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
State Key Laboratory of Photocatalysis On Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350108, PR China. Electronic address:
The development of durable and highly efficient visible-light-driven photocatalysts is essential for the photocatalytic ozonation process towards degrading organic pollutants. This study presents CN-MA, a novel photocatalyst synthesized by grafting carbon nitride (CN) with single-atom Mn and 2-hydroxy-4,6-dimethylpyrimidine (HDMP) via one-step thermal polymerization. Experimental characterization and theoretical calculation results reveal that incorporating single-atom Mn and HDMP into CN alters the charge density distribution on the heptazine rings.
View Article and Find Full Text PDFChemistry
December 2024
Lanzhou University, College of Chemistry and Chemical Engineering, Lanzhou Tianshui south street 222, 730000, Lanzhou, CHINA.
Dual single-atom catalysts have attracted considerable research interest due to their higher metal atom loading and more flexible active sites compared to single-atom catalysts (SACs). We pioneered the one-step synthesis of sheets copper-cobalt graphitic carbon nitride dual single-atom (S-Cu/Co-g-C3N4) using folding fan-shaped aluminum foil as a template, and used them as catalysts in the epoxidation of styrene respectively. Through XAFS(X-ray Absorption Fine Structure) and other characterizations, it is found that Cu and Co single atoms are stabilized separately on g-C3N4 via coordination with nitrogen (N), hindered the ordered growth of sheets, and formed more pore structures, which not only increased more catalytically active sites, but also effectively prevented the flakes re-aggregate during the catalytic process.
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