A5037383256- Electron and X-Ray Spectroscopy Techniques
- Advanced Electron Microscopy Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Materials Characterization Techniques
- Nuclear materials and radiation effects
- Advanced Condensed Matter Physics
- Ion-surface interactions and analysis
- Nuclear Materials and Properties
- Magnetic properties of thin films
- Advancements in Photolithography Techniques
- Scientific Computing and Data Management
- Integrated Circuits and Semiconductor Failure Analysis
- Machine Learning in Materials Science
- Nuclear Physics and Applications
- Geological and Geochemical Analysis
- Semiconductor materials and devices
- Surface and Thin Film Phenomena
- Physics of Superconductivity and Magnetism
- Advanced X-ray Imaging Techniques
- Distributed and Parallel Computing Systems
- Fusion materials and technologies
- Electronic and Structural Properties of Oxides
- Crystallography and Radiation Phenomena
- Hydrogen embrittlement and corrosion behaviors in metals
- Non-Destructive Testing Techniques
University of Chicago
2023-2025
Argonne National Laboratory
2015-2024
Thermo Fisher Scientific (Sweden)
2022
University of Manchester
2014-2017
Center for Nanoscale Materials
2016
Uppsala University
2015
IIT@MIT
2014
Brookhaven National Laboratory
2014
Microscopy Society of America
2011
Australian Nuclear Science and Technology Organisation
2008
We report the design and synthesis of multimetallic Au/Pt-bimetallic nanoparticles as a highly durable electrocatalyst for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. This system was first studied on well-defined Pt FePt thin films deposited Au(111) surface, which has guided development novel synthetic routes toward shape-controlled Au coated with Pt-bimetallic alloy. It been demonstrated that these Au/FePt3 possess both high catalytic activity alloys superior...
Measurements of the transport critical-current density (Jc), magnetization Jc, and magnetoresistance in a number bulk sintered samples Y1Ba2Cu3Ox from several different laboratories indicate that Jc is limited by weak-link regions between high regions. The has Josephson character, decreasing two orders magnitude as magnetic field increased 0.1 to 10 mT at 77 K. An examination grain-boundary region shows no observable impurities or second phases scale [001] lattice planes (∼12 Å). effect...
Process management is an extremely important concept in both business and scientific communities. Several workflow tools have been proposed recent years offering advanced functionality various domains. In the world, vendors offer commercial customized solutions targeting specific users. several open-source are freely available. However they directed toward service aggregation rather than distributed process management. Little consideration given to needs of client terms mapping flow client....
Lead-based chemistry was initiated in ancient Egypt for cosmetic preparation more than 4000 years ago. Here, we study a hair-dyeing recipe using lead salts described text since Greco-Roman times. We report direct evidence about the shape and distribution of PbS nanocrystals that form within hair during blackening. It is remarkable composition supramolecular organization keratins can control nanocrystal growth inside hair.
Understanding and controlling the three-dimensional structure of block copolymer (BCP) thin films is critical for utilizing these materials sub-20 nm nanopatterning in semiconductor devices, as well membranes solar cell applications. Combining an atomic layer deposition (ALD)-based technique enhancing contrast BCPs transmission electron microscopy (TEM) together with scanning TEM (STEM) tomography reveals characterizes structures poly(styrene-block-methyl methacrylate) (PS-b-PMMA) great...
Self-assembling biomolecules that form highly ordered structures have attracted interest as potential alternatives to conventional lithographic processes for patterning materials. Here, we introduce a general technique nanoparticle arrays using two-dimensional crystals of genetically modified hollow protein called chaperonins. Constrained chemical synthesis transition metal nanoparticles is initiated templates functionalized with polyhistidine sequences. These are into because the...
The excitation of surface plasmons in individual silver nanowires and gold nanorods is investigated by means high-resolution electron energy loss spectroscopy a transmission microscope. transverse longitudinal modes these nanostructures are resolved, the size variation plasmon peaks studied. effect electromagnetic coupling between closely spaced nanoparticles also observed. Finally, relation energy-loss measurements optical nanoparticle discussed.
This paper presents an investigation of the limitations and optimisation energy dispersive X-ray (EDX) tomography within scanning transmission electron microscope, focussing on application technique to characterising 3D elemental distribution bimetallic AgAu nanoparticles. The detector collection efficiency when using a standard holder is characterised tomographic data set from single nanoparticle compared low background double tilt holder. Optical depth profiling used investigate angles...
One challenge existing since the invention of electron-beam lithography (EBL) is understanding exposure mechanisms that limit resolution EBL. To overcome this challenge, we need to understand spatial distribution energy density deposited in resist, is, point-spread function (PSF). During EBL exposure, processes electron scattering, phonon, photon, plasmon, and emission resist are combined, which complicates analysis PSF. Here, show measurement delocalized transfer by using chromatic...
Abstract The use of analytical spectroscopies during scanning/transmission electron microscope (S/TEM) investigations micro- and nano-scale structures has become a routine technique in the arsenal tools available to today’s materials researchers. Essential implementation successful application spectroscopy characterization is integration numerous technologies, which include optics, specimen holders, associated detectors. While this combination been achieved many instrument configurations,...
An understanding of how complex nanoscale morphologies emerge from synthesis would offer powerful strategies to construct soft materials with designed structures and functions. However, these kinds have proven difficult characterize, therefore manipulate, because they are three-dimensional (3D), nanoscopic, often highly irregular. Here, we studied polyamide (PA) membranes used in wastewater reclamation as a prime example this challenge. Using electron tomography quantitative morphometry,...
Chaperonins are high molecular mass double-ring structures composed of 60-kDa protein subunits. In the hyperthermophilic archaeon Sulfolobus shibatae two chaperonin proteins represent approximately 4% its total and have a combined intracellular concentration >30 mg/ml. At concentrations >/= 0.5 mg/ml purified chaperonins form filaments in presence Mg2+ nucleotides. Filament formation requires nucleotide binding (not hydrolysis), occurs at physiological temperatures biologically relevant...
The magnetization reversal mechanism in an array of submicron elliptical Permalloy elements with aspect ratio 1.4:1 is investigated using the diffracted magneto-optic Kerr effect technique, Lorentz scanning transmission electron microscopy, and microscopy. experimental results are interpreted from a comparison micromagnetic simulations. found to be dependent on direction magnetic field occur via formation one or two vortices; vortex state nucleated when applied along short axis. For long...
Using electron correlograph analysis we show that coherent nanodiffraction patterns from sputtered amorphous silicon indicate there is more local crystallinity in unannealed than was previously suspected. By comparing with simulations for various models within a typical film substantial volume fraction (>50%) topologically crystalline correlation lengths up to 2 nm. Electron variant of the fluctuation microscopy technique and its sensitivity ordering derived four-body correlations.
A new design of <italic>in situ</italic> liquid cells is demonstrated, providing the first nanometer resolution elemental mapping nanostructures in solution.
A nanochannel liquid cell was used to quantify the electron inelastic mean free path (<italic>λ</italic><sub>IMFP</sub>) in water. The experimental values show large offsets from generally accepted models, and can be determine thickness a cell.
Restacked two-dimensional (2D) materials represent a new class of membranes for water-ion separations. Understanding the interplay between 2D membrane's structure and constituent material's surface chemistry to its ion sieving properties is crucial further membrane development. Here, we reveal, tune via covalent functionalization, MoS2-based membranes. We find features on both ∼1 nm (interlayer spacing) ∼100 (mesoporous voids layers) length scales that evolve with hydration level. The...