Whereas the atom probe is regarded almost exclusively as a technique for 3D chemical microanalysis of solids with the highest chemical and spatial resolution, we demonstrate that the technique can be used for detailed crystallographic determinations. We present a new method for the quantitative determination of crystal structure (plane spacings and angles) using a Hough transformation of the reconstructed atom probe data. The resolving power is shown to be high enough to identify poorly established, discontinuous planes that are typical in semiconducting materials. We demonstrate the determination of crystal geometry around a grain boundary and the use of the technique for the optimisation of tomographic reconstruction. We propose that this method will enable automatic spatial analysis and, ultimately, automated tomographic reconstruction in atom probe microscopy.
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http://dx.doi.org/10.1016/j.ultramic.2010.11.018 | DOI Listing |
Microsc Microanal
January 2025
Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada.
Atom probe tomography (APT) enables three-dimensional chemical mapping with near-atomic scale resolution. However, this method requires precise sample preparation, which is typically achieved using a focused ion beam (FIB) microscope. As the ion beam induces some degree of damage to the sample, it is necessary to apply a protective layer over the region of interest (ROI).
View Article and Find Full Text PDFFood Chem
January 2025
Department of Chemistry, College of Science, University of Sulaimani, Qliasan St., 46002 Sulaymaniyah, Kurdistan region, Iraq. Electronic address:
Chemically-synthesized Nanozymes that are widely used as alternatives to enzymes face challenges such as high precursor costs, complex preparation processes, and limited catalytic efficiency. To overcome these drawbacks, we introduce naturally derived nanozymes, nanomineralzymes, as a promising alternative, offering benefits like affordability, cost-effectiveness, and scalability. Chalcopyrite (CP, CuFeS) was sourced from a mineral deposit, and CP nanoparticles were produced by milling.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States.
Two-dimensional infrared (2D IR) spectroscopy is a powerful technique for measuring molecular heterogeneity and dynamics with a high spatiotemporal resolution. The methods can be applied to characterize specific residues of proteins by incorporating frequency-resolved vibrational labels. However, the time scale of dynamics that 2D IR spectroscopy can measure is limited by the vibrational label's excited-state lifetime due to the decay of 2D IR absorption bands.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
Department of Materials Science, Montanuniversität Leoben, 8700 Leoben, Austria.
Nanoparticles are essential for energy storage, catalysis, and medical applications, emphasizing their accurate chemical characterization. However, atom probe tomography (APT) of nanoparticles sandwiched at the interface between an encapsulating film and a substrate poses difficulties. Poor adhesion at the film-substrate interface can cause specimen fracture during APT, while impurities may introduce additional peaks in the mass spectra.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Spectroscopy Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
The ion binding to the lipid/water interface can substantially influence the structural, functional, and dynamic properties of the cell membrane. Despite extensive research on ion-lipid interactions, the specific effects of ion binding on the polarity and hydration at the lipid/water interface remain poorly understood. This study explores the influence of three biologically relevant divalent cations─Mg, Ca, and Zn─on the depth-dependent interfacial polarity and hydration of zwitterionic DPPC lipid in its gel phase at room temperature.
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