Showing papers on "Electron tomography published in 1997"
TL;DR: After a general introduction to three-dimensional electron microscopy and particularly to electron tomography (ET), the perspectives of applying ET to native (frozen-hydrated) cellular structures are discussed and the question of whether it is a realistic long-term goal to visualize or identify macromolecules in cells frozen in toto or in frozen sections of cells is addressed.
403 citations
TL;DR: The application of this technique to the reconstruction of large, complex structures such as mitochondria is described in conjunction with several tools for segmentation, measurement, classification, and visualization.
125 citations
TL;DR: In spite of the missing-wedge effect that is especially obvious in the study of membrane-filament interaction, single-axis tilt tomography was found to be an appropriate (in fact the only available) method for this kind of investigation.
107 citations
TL;DR: An approach based on a multiscale transformation, e.g., the wavelet transformation, in conjunction with a nonlinear filtration of the transform coefficients, which turns out to be superior to conventional filter techniques, such as the median filter or the Wiener filter.
52 citations
TL;DR: In this paper, a refined atomic model of the Cu/Al2O3 interface is retrieved by iterative digital image matching and multiple scattering calculations based on this model are vital to explain the interface specific components in the EELS O-K edge.
51 citations
TL;DR: A method based on Fourier transforms for obtaining a 3-D reconstruction from a paracrystalline object with static disorder using all of the Fourier coefficients is described as well as prospects for extension of the method to radiation-sensitive specimens.
50 citations
TL;DR: Low-dose automated tomographic projection series of a triad junction of frog sartorius muscle was semiautomatically collected and a 3-D reconstruction of this organelle was made.
48 citations
TL;DR: A model for the packaging of nuclear pre-mRNAs in lnRNP particles where each substructure represents a functional unit is proposed which is compatible with the requirements for alternative splicing in multi-intronic pre- mRNAs, and with the fact that the splicing of multi- intronicPre-m RNAs does not occur in a sequential manner.
46 citations
TL;DR: In this paper, it was shown that a very fine beam of diameter less than 0.05 nm can be formed in the region within 1 or 2 nm of the atomic focuser when an electron beam of energy 100-400 keV passes through a single heavy atom, or a row of atoms parallel to the beam.
40 citations
Patent•
18 Dec 1997TL;DR: In this paper, a system for determining one or more critical dimensions(s) of a semiconductor structure comprising a scanning electron microscope and a parallel distributed process operationally connected to an output of a scanner is presented.
Abstract: A system for determining one or more critical dimension(s) of a semiconductor structure comprising a scanning electron microscope and a parallel distributed process operationally connected to an output of a scanning electron microscope. Said parallel distributed process containing coefficients that provide a multi dimensional mapping space for the output of said scanning electron microscope to map to an output value that provides information on the dimensions of the semiconductor structure.
35 citations
TL;DR: In this paper, the atomic process of epitaxial growth was observed cross sectionally in situ with time-resolved high-resolution transmission-electron microscopy, and various types of growth phenomena, such as nucleation center formation, structural fluctuations, shape modulation, secondary nucleation, and coalescence, were analyzed in real space at a spatial resolution of 0.2 nm and a time resolution of 1/60 s.
Abstract: Gold was vacuum deposited on a (001) surface of magnesium oxide inside a high-resolution electron microscope. The atomic process of epitaxial growth was observed cross sectionally in situ with time-resolved high-resolution transmission-electron microscopy. Various types of growth phenomena, such as nucleation center formation, structural fluctuations, shape modulation, secondary nucleation, and coalescence, were analyzed in real space at a spatial resolution of 0.2 nm and a time resolution of 1/60 s. It was found that a central corner of a cluster is truncated and constructed repeatedly during the growth.
TL;DR: The scanning electron microscope (SEM) now uses a wide range of operating conditions to target the desired sample volume, sophisticated modeling techniques to interpret the data, and novel imaging modes to derive new types of information.
Abstract: Current materials are usually complex in chemistry, three-dimensional in form, and of rapidly diminishing microstructural scale. To characterize such materials the scanning electron microscope (SEM) now uses a wide range of operating conditions to target the desired sample volume, sophisticated modeling techniques to interpret the data. It also uses novel imaging modes to derive new types of information. These include depth-resolved three-dimensional data, and spatially resolved crystallographic data.
01 Apr 1997
TL;DR: In this paper, the magnetic field distribution from the MFM tip was reconstructed by tomography using the Lorentz electron microscopy (LEM) technique, and the reconstructed field was consistent with the predicted form.
Abstract: Lorentz electron microscopy has been applied to the study of the magnetic field distribution from MFM tips. Data acquired by this technique has been used to reconstruct the field distribution from the MFM tip by tomography. Initial results have been obtained from commercial tips which have been magnetised along the tip axis. The reconstructed field is consistent with the predicted form.
TL;DR: Current efforts include combining electron microscopic tomography and video‐enhanced light microscopy to correlate ultrastructural variation with the direction of chromosome motion during mitosis.
Abstract: Tomography is a powerful tool for obtaining three-dirotation geometry. Although single-axis data collection is stanmensional information from transmission electron microscopy, but its dard in biomedical imaging (e.g., CAT scan, scanning via compuapplication faces unique challenges. A single-axis tilt geometry for terized axial tomography), other data collection geometries are data collection results in anisotropic resolution because full angular also routinely used. coverage is not feasible for most specimen preparations. This effect In the last 10 years, electron tomography has proved to be an can be minimized by combining two single-axis tilt series that have effective tool for 3D structure–function determination in cellular been collected orthogonal to each other. Rapid freezing has been and molecular biology (reviewed in [6–8]) . Recent successful successfully used to preserve the native structure of biological speciapplications include determining the location of microtubule initimens in a form that can be visualized in the high-vacuum environment ation sites in centrosomes isolated from fruit fly embryos [9] , required for electron microscopy; however, these preparations are extremely labile to electron exposure. As a result, application of todemonstrating dynamic changes that occur in muscle Z bands mography to frozen-hydrated specimens has only recently become with contraction [10], characterizing the arrangement and morfeasible with the development of automatic data collection, and with phology of crystals formed during the initial events of bone fora renewed appreciation for the principle of dose fractionation. Even mation [11,12], and providing new insight into the folding of with the limitations of traditional specimen preparations and convenDNA into chromosomes [13,14]. Here we briefly review the tional methods of data collection, electron microscopic tomography methodology, including recent efforts to overcome radiation damhas been successfully employed to probe the structure and function age and an unfavorable specimen geometry, and present a new of several important cellular components. Current efforts include comapplication where electron tomography is combined with videobining electron microscopic tomography and video-enhanced light enhanced light microscopy to correlate structural determination microscopy to correlate ultrastructural variation with the direction of with motion. chromosome motion during mitosis. q 1997 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 8, 175–187, 1997
Patent•
31 Oct 1997
TL;DR: In this paper, an inspection method and device using an electron beam that can solve various problems caused by obliquely applying the electron beam is provided, where the primary and/or secondary original image of a secondary electron and a reflection electron are generated corresponding to change in the shape, the quality of a material and the potential of the surface of the sample.
Abstract: PROBLEM TO BE SOLVED: To provide inspection method and device using an electron beam that can solve various problems caused by obliquely applying the electron beam. SOLUTION: A device is provided with electron beam application parts 1-10 for applying an electron beam 31 to a sample 11, mapping projection optics parts 16-21 for forming the primary and/or secondary original image of a secondary electron and a reflection electron 32 being generated corresponding to change in the shape, the quality of a material, and the potential of the surface of the sample, electron beam detection parts 22-27 for outputting a detection signal based on the primary and/or secondary original image, an image display part 30 for displaying the primary and/or secondary original image of the surface of the sample by receiving the detection signal, and electron beam deviation parts 27 and 43-44 for changing an incident angle to the sample of the electron beam being applied from the electron beam application parts and a drawing angle to the mapping projection optics parts of the secondary electron and the reflection electron.
TL;DR: In this article, a self-assembled decanethiol monolayer is damaged by primary beam electrons and the damaged portion is exchanged with another thiol-containing molecule by immersion in solution.
Abstract: A method for demonstrating the scattering of the primary electron beam in the presence of a gas has been developed. A self-assembled decanethiol monolayer is damaged by primary beam electrons. The damaged portion of the mono-layer is exchanged with another thiol-containing molecule by immersion in solution. The resulting film is imaged using a secondary ion mass spectrometer. Three-dimensional reconstruction of the data yields a representation of scattered electrons in the gaseous environment of the environmental scanning electron microscope.
Patent•
18 Dec 1997
TL;DR: In this paper, a dicing saw machining is used to cut a sample and then a reaction product is deposited on the sample, which is covered with a plasma polymerization film.
Abstract: PROBLEM TO BE SOLVED: To easily prepare a sample for a transmission electron microscope at a specific position. SOLUTION: A sample 1 is sliced by dicing saw machining. An electron beam is radiated near a specific observation position of the sample 1, and a reaction product 3 is deposited. The sample 1 is covered with a plasma polymerization film 4. A focused ion beam is scanned on the sample 1, and the specific observation position is spatter-etched to the thickness of 0.1 μm. COPYRIGHT: (C)1999,JPO
TL;DR: In this paper, the authors compared the resolution and contrast of plasmon energy-loss electrons in an energy-filtered transmission electron microscope with a LaB 6 gun and showed that with an energy slit 3 eV in width, the image showed the same resolution as that recorded using the zero loss electrons in a 300 kV transmission electron microscopy.
TL;DR: In this paper, an energy-filtering transmission electron microscope (EFTEM) was used for mass determination of biomolecular assemblies with an accuracy and reproducibility comparable to that achieved by scanning transmission electron microscopy (STEM).
TL;DR: In this article, the structure of Bi4(Sr0.75La0.25)8Cu5Oy was studied by a image-processing technique based on the combination of high-resolution electron microscopy and electron diffraction.
TL;DR: It is deduced that scanning tunnelling microscopy images are the result of a transmission of electrons through the gap between the scanning tip and the conductive support across the biological specimen.
TL;DR: In this paper, the dependence of electron microscopic contrast on atomic number has been separated experimentally from that on mass thickness in a Philips CM20 transmission electron microscope at 200kV, and a procedure for specimen thickness determination is proposed in conjunction with composition determination by energy dispersive X-ray spectrometry.
TL;DR: It is demonstrated that only four optimal focus levels are required to effectively restore the coherent component of the exit wave, and a new interpretation of the restored amplitude and phase components where the specimen mass-density is proportional to the logarithm of the amplitude component and linearly related to the phase component is proposed.
03 Feb 1997
TL;DR: In this article, a method is described to measure the coherence of the electron beam within a scanning transmission electron microscope (STEM) using a cold field emission gun, after acceleration to 100 keV, the emitted electrons are focused to a crossover at a crystalline specimen.
Abstract: A method is described to measure the coherence of the electron beam within a scanning transmission electron microscope (STEM). The microscope employs a cold field emission gun. After acceleration to 100 keV, the emitted electrons are focused to a cross-over at a crystalline specimen. The visibility of interference features between diffracted discs at the image plane are a measure of the “effective source coherence function” at the specimen plane. Experimental results are shown comparing two designs of gun. It is seen that ambient stray fields in the immediate area dominate our microscope's performance. It is intended to utilise this measurement technique to characterise modified electron guns installed in the future.
TL;DR: In this article, the authors used a CM200 FEG operating at 200 kV with a 1 rm probe, and the carbon mass was formed during a 300 second probe exposure at a β-tilt of −200°.
Abstract: The issue of specimen contamination becomes more important at a rate proportional to the use of high-brightness electron source Transmission Electron Microscopes (TMM). The trend in the transmission electron microscopy of materials science specimens is to use higher-voltage microscopes incorporating field emission gun technology [1]. These FEG TEMs combine smaller electron probes with increased beam current, allowing high resolution specimen imaging and enhanced analytical data collection. This is of particular importance for semiconductor specimens which demand fine-probe microanalyis. Small, high current electron probes tend to increase the migration rates of hydrocarbon contamination on the specimen’s surface to the impingement point of the electron probe as shown in Figure 1. This image was generated using a CM200 FEG operating at 200 kV with a 1 rm probe. The carbon mass was formed during a 300 second probe exposure at a β-tilt of −200°. Imaging was conducted at a β-tilt of +400°. These types of carbon deposits often times obstrnct imaging and precludes acceptable analytical results. By plasma cleaning the specimen, contamination is removed and the results obtained by high resolution electron microscopy (HREM), scanning uanmission electron microscopy (STEM) and analytical electron microscopy (AEM) 20pm using EDS or electron energy loss spectroscopy (EELS) are greatly enhanced [2-6].
Recent instrumentation developments have resulted in the application of a high fiequency, low energy, reactive gas plasma that chemically removes hydrocarbon contamination from both the TEM specimen holder and the specimen without altering its properties. Critical aspects of the plasma generation, ion energy, electrode location, process gas, and vacuum technology are discussed. The effect of plasma processing parameters on various materials research specimens will be presented.
TL;DR: It is shown that image contrast can be dramatically improved with the use of an energy filter, and the spatial resolution of energy-selected ionization edge electron images is dominated by the signal-to-noise ratio.
Abstract: Energy-filtered (or selected) electron imaging is one of the future directions of highresolution electron microscopy (HREM). In this paper, the characteristics and applications of energy-selected electron imaging at high-resolution for structure determinations are illustrated. It is shown that image contrast can be dramatically improved with the use of an energy filter. High-resolution chemical-sensitive imaging using ionization-loss electrons is demonstrated in studies of Ni/Ti and Al/Ti multilayer thin films. It is also shown that the spatial resolution of energy-selected ionization edge electron images is dominated by the signal-to-noise ratio. Experimental parameters which may be selected to improve the signal-to-noise ratio are discussed.
TL;DR: In this article, two new forms of electron holography involving a transmission electron microscopy (STEM) instrument and suitable for the study of surface structure have been proposed for surface structure.
Abstract: Scanning transmission electron microscopy (STEM) instruments have some particular advantages as compared with the more common transmission electron microscopes for some applications to surface research. Imaging of surfaces and mapping of the elemental distributions on surfaces with spatial resolutions approaching 1 nm are possible in an ultrahigh-vacuum STEM instrument when the low-energy secondary electrons or the Auger-emitted electrons are collected with high efficiency. In the imaging of surface layers on thin-film substrates, viewed in transmission, the use of a thin annular detector in STEM may greatly enhance the contrast, as illustrated by the case of the imaging of very thin nanocrystalline carbon layers on much thicker amorphous SiO2 films. The scanning reflection mode in a STEM instrument can provide some useful forms of contrast in images of surface structure. Standing wave fields can be formed on the surfaces of crystals with electrons, as with X-rays, one advantage of the electron case being that the standing wave fields may be imaged. Two new forms of electron holography, involving a STEM instrument and suitable for the study of surface structure, are proposed.
TL;DR: In this article, the authors proposed a method to improve the quality of the data collected by the data collection system of the Internet.Abstracts are not published in this journal. But
Abstract: Abstracts are not published in this journal