Published in Journal of bone and mineral metabolism
The goal is to propose a material scientific hypothesis for the atomic arrangement of calcium phosphates during the mineralization of bones. It was reached by the analysis of bones of healthy and osteoporotic rats using analytical transmission electron microscopic methods. Electron diffraction patterns show hydroxyapatite (HAP) as dominant phase wi...
Published in Ultramicroscopy
We present progress toward the quantitative interpretation of phase contrast images obtained using a hole-free phase plate (HFPP) in a transmission electron microscope (TEM). We consider a sinusoidal phase grating test object composed of ~5 nm deep groves in a ~13 nm thick amorphous silicon membrane. The periodic grating splits the beam current int...
Nanoscale strain mapping by four-dimensional scanning transmission electron microscopy (4D-STEM) relies on determining the precise locations of Bragg-scattered electrons in a sequence of diffraction patterns, a task which is complicated by dynamical scattering, inelastic scattering, and shot noise. These features hinder accurate automated computati...
Smectite interlayer water plays a key role on the mobility of elements and molecules, but also in a variety of geological processes. In contrast to saponite and hectorite, whose layer charge originates from isomorphic substitutions, stevensite layer charge originates from the presence of octahedral vacancies. Despite its common occurrence in lacust...
Published in Ultramicroscopy
The cryoEM method Microcrystal Electron Diffraction (MicroED) involves transmission electron microscope (TEM) and electron detector working in synchrony to collect electron diffraction data by continuous rotation. We previously reported several protein, peptide, and small molecule structures by MicroED using manual control of the microscope and det...
Published in Micron (Oxford, England : 1993)
A new computer program, TEMUC3, has been developed for unit-cell determination of crystal phases using electron diffraction data. A graphic user-friendly interface was designed for the following operations, (i) a reciprocal lattice is reconstructed from a tilt series of electron diffraction patterns; (ii) a Niggli cell is generated from the two ele...
Published in Ultramicroscopy
We investigate imaging of moiré structures in free-standing twisted bilayer graphene (TBG) carried out by transmission electron microscopy (TEM) in diffraction and in-line Gabor holography modes. Electron diffraction patterns of TBG acquired at typical TEM electron energies of 80-300 keV exhibit the diffraction peaks caused by diffraction on indivi...
Published in Cellulose
AbstractFollowing the first electron micrographs of cotton in 1940, the development of transmission electron microscopy applied to native cellulose has been evolving in a series of successive advances. At first, faced with the weak contrast of the early images, the operators had to use specific electron-dense contrasting agents to reveal the ultras...
Published in Cellulose
AbstractTransmission electron microscopy (TEM) has played a significant role in the characterization of cellulosic materials, especially the so-called “nanocelluloses” (nanofibers and nanocrystals), from visualizing nanoscale morphologies to identifying crystal structures. With scientific and industrial interest in nanocelluloses rapidly increasing...
Continuing progress in laser technology has enabled dramatic advances in laser wakefield acceleration (LWFA), a technique that permits driving particles by electric fields three orders of magnitude higher than in conventional radio-frequency accelerators. Due to significantly reduced space charge and velocity dispersion effects, the resultant relat...
