Showing papers in "Ultramicroscopy in 1989"

TL;DR: The use of a high-angle annular detector on a scanning transmission electron microscope (STEM) for imaging crystalline materials with strong chemical sensitivity is described in this paper, where the image can be used to form an elemental map with high efficiency which can be quantified directly in terms of atomic concentrations.

TL;DR: A new concept in EELS digital acquisition and processing is defined: the spectrum-image, a 3D array of nxnxs numbers, the first two axes of which correspond to the x − y position on the specimen as for any image, while the third is associated to a complete energy-loss spectrum.

TL;DR: The epitaxial growth of silicon on Si(111)-(7×7) and Si(001)-(2×2) substrates at temperatures between 300 and 700 K was studied using scanning tunneling microscopy as mentioned in this paper.

TL;DR: A generalized multislice theory is employed to simulate the annular dark field (ADF) images, in scanning transmission electron microscopy (STEM), taking into account the inelastic thermal diffuse scattering (TDS).

TL;DR: In this paper, the relationship between the thermodynamic stability of a particular surface orientation and the properties of the equilibrium crystal shape is discussed, and the formation of a sharp edge in the equilibrium surface shape when temperature or impurity pressure is changed manifests itself by reversible surface faceting.

TL;DR: In this paper, the basic principles of low energy electron microscopy combined with low-energy electron diffraction and photo-emission electron microscope are described, and applications to in-situ studies of clean surfaces, and surface processes involving foreign atoms are reviewed.

TL;DR: In this paper, a multi-resolution approach to the 3D-reconstruction problem from electron microscope tilt series is presented, which is designed for the reconstruction from a tilt series with a limited number of projections where the tilt angles are assumed to be known.

TL;DR: In this paper, the HPI layer was obtained at tunneling currents lower than 0.5 pA and tunneling voltages up to 10 V and at a humidity in the range between 30% and 45%.

TL;DR: Results indicate that the native morphology and dimensions of biological macromolecules are better preserved in frozen-hydrated samples when compared with more conventional electron microscopy techniques such as negative-staining, metal shadowing or thin-sectioning.

TL;DR: The present analysis shows that the resolution in the high-intensity plane is better than in the plane of least confusion, and the effects of aberrations in these two planes are quite different.

TL;DR: In this paper, a projection microscope was built by positioning an ultrasharp tip, prepared by field-ion microscopy techniques, in close proximity to a partly transparent carbon foil.

TL;DR: In this paper, the applicability of a proposed formula for estimating the required correction is tested on a variety of materials (with atomic number ranging from 14 to 69) and zone axes.

TL;DR: In this article, it was shown that in the limit of a thin specimen, it is possible to transform all the intensity information available in the microdiffraction plane of a scanning transmission electron microscope (STEM) to obtain the complex specimen function at wavelength-limited resolution.

TL;DR: In this article, a new dedicated ultra-high-vacuum scanning transmission electron microscope (UHV-STEM) has been developed for the NSF HREM facility at Arizona State University, in conjunction with VG Microscopes Ltd. This instrument is fitted with a specimen preparation chamber in which vacua of better than 5x10-10 mbar can be routinely achieved; the pressure inside the column is better than 10-10mbar.

TL;DR: In this paper, structural changes occurring at or near surfaces during irradiation in the electron microscope have been reported in a broad range of oxide systems, but only relatively recently have they been investigated primarily in terms of radiation damage.

TL;DR: A methodology for tip and specimen-support manufacturing is described which allows for scanning tunneling microscopy (STM) and transmission electron microscope (TEM) on identical areas of biological specimens, at comparable resolution, to investigate tip- specification interaction on native air-dried phage T4 polyheads.

TL;DR: In this paper, a dedicated FEG-STEM was used to perform chemical mapping on individual metal clusters in the nanometer range by processing sequences of energy-filtered images recorded at different energy losses before and after a characteristic edge.

TL;DR: In this paper, a new method is proposed to measure and correct defocus, astigmatism and beam tilt misalignment of a transmission electron microscope (TEM) automatically, which is applicable to low-dose, high-resolution electron microscopy if the specimen may be described as a weak-phase object.

TL;DR: In this article, high-resolution reflection electron microscopy (HR-REM) was used to resolve the 5-fold superlattice fringes of the 5×2 structure of Si(111)7×7 surface.

TL;DR: In the past few years, there has been considerable activity in adapting the theory of dielectric excitation by a moving classical point charge to provide quantitative interpretation of valence loss spectra obtained from localised regions in both STEM and REM modes as discussed by the authors.

TL;DR: In this paper, a reproducible and rapid preparation technique for high-quality TEM specimens of semiconducting materials is reported, where the required equipment is available in most laboratories working on TEM in the field of solid state materials.

TL;DR: In this paper, several Fourier filters enhancing the signal-to-noise ratio (S-NOR) were systematically examined in order to find an optimum between reduction of noise and preservation of relevant non-periodic image detail.

TL;DR: In this paper, a formula was proposed for rapidly calculating inner-shell ionization cross-sections, making use of X-ray absorption data, energy-loss measurements and atomic scattering theory.

TL;DR: In this article, a simple method based on the use of holey grids is described which overcomes the difficulty in retaining a sufficient amount of specimen on the support grids is sometimes a major obstacle in electron crystallography.

TL;DR: The software package that has been written can serve as a basis for applying artificial intelligence methodologies to analysis of electron micrographs and is demonstrated using electron micro graphs of ribosomes and ribosomal subunits.

TL;DR: This note describes a practical improvement in the computational efficiency of the spectral signal-to-noise ratio (SSNR) resolution criterion for correlation-averaged images, and it is shown that, for negatively stained data, a judicious compromise is achieved with 10 less than or equal to ng less than and equal to 20.

TL;DR: In this paper, secondary electron signals with 1 nm spatial resolution and 1 eV energy resolution obtained in a STEM are presented and discussed, where stopping power theory identifies inner shell excitations and well localised valence excitations as the dominant SE generation mechanisms and accounts for the spatial resolution obtained.

TL;DR: The analytical electron microscope (AEM) can be used to obtain quantitative elemental analysis with a spatial resolution of 1μm with accompanying composition changes of as mentioned in this paper, where the AEM is used for elemental analysis at the same time of day.

TL;DR: In this paper, a review of studies of the equilibrium forms of metallic crystals is given, where the facet boundary changes from a smooth to a sharp edge near the bulk melting points.

TL;DR: In this paper, a review of the kinetics of ordering at surfaces are briefly reviewed, including discussions of the growth law and diffusion in a nonequilibrium environment both for phase coexistence and for single stable phases.