Transmission electron microtomography without the “missing wedge” for quantitative structural analysis

Kawase, Noboru; Kato, Mitsuro; Nishioka, Hideo; Jinnai, Hiroshi

doi:10.1016/j.ultramic.2006.04.007

Cited by 211 publications

(156 citation statements)

References 21 publications

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“…It should be mentioned that the present result may contain approximately 12% of error in z-direction parallel to optical axis due to the missing wedge, which is introduced by a limited maximum tilt angle. 12) Here, also note that a characteristic triangular shape can be seen at the edge of an LPSO band as marked by a circle. Although the detailed growth mechanism of the LPSO is not clear, it is presumed that such irregular or characteristic shapes are related to the lateral growth mechanism of the LPSO.…”

Section: Resultsmentioning

confidence: 85%

Three-Dimensional Shapes and Distributions of Long-Period Stacking Ordered Structures in Mg97Zn1Gd2 Cast Alloys Characterized by Electron Tomography

et al. 2015

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Three-dimensional (3D) configurations of 14H long-period stacking ordered (LPSO) structures formed in Mg 97 Zn 1 Gd 2 cast alloys at intermediate stages of the formation process have been studied by single tilt-axis electron tomography using high-angle annular dark-field scanning transmission electron microscopy. Lateral morphology of the 14H LPSO is clearly visualized by reconstructing 3D volumes. An existence of "dent-shaped" area was found in a 3D reconstructed volume for the first time. The edge of LPSO shows a characteristic triangular shape with an angle of 60°, which indicates that the growth front is parallel to f11 20g Mg . It is suggested that in-plane irregular or characteristic shapes are related to the lateral growth mechanism of LPSO. Electron tomography has proven to be an indispensable tool to characterize in-plane structural information of LPSO formed in ¡-Mg matrix.

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Section: Resultsmentioning

confidence: 85%

Three-Dimensional Shapes and Distributions of Long-Period Stacking Ordered Structures in Mg97Zn1Gd2 Cast Alloys Characterized by Electron Tomography

et al. 2015

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“…As mentioned earlier, this is caused by reconstructing from a limited angular range (the maximum possible is 180°) and occurs for several reasons-the sample holder may obstruct the field of view at high tilt angles; the microscope's goniometer may not be able to tilt through the full −90°-+90°range, or the sample is in the form of a plane (as opposed to an isolated particle or a fabricated cylindrical pillar [26]) and images taken at high tilt angles have too high an effective sample thickness for good quality imaging. Unless tilt series are taken of pillar samples or individual particles and using a sample holder which allows full rotation without obstructions, there will always be a missing wedge of information for which to account.…”

Section: Missing Wedgementioning

confidence: 99%

Machine learning as a tool for classifying electron tomographic reconstructions

Staniewicz

Midgley

2015

Adv Struct Chem Imag

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Electron tomographic reconstructions often contain artefacts from sources such as noise in the projections and a "missing wedge" of projection angles which can hamper quantitative analysis. We present a machine-learning approach using freely available software for analysing imperfect reconstructions to be used in place of the more traditional thresholding based on grey-level technique and show that a properly trained image classifier can achieve manual levels of accuracy even on heavily artefacted data, though if multiple reconstructions are being processed, a separate classifier will need to be trained on each reconstruction for maximum accuracy.

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“…More tilts and a larger tilt range adds information and results in a higher quality reconstruction. Specimens with a needle shape geometry may permit the full 180° tilt rage 14 . However, practical limitations, such as the sample or stage geometry, often prevent full specimen rotation in the microscope-±70° is a common upper limit.…”

Section: Introductionmentioning

confidence: 99%

Breaking the Crowther limit: Combining depth-sectioning and tilt tomography for high-resolution, wide-field 3D reconstructions

et al. 2014

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To date, high-resolution (< 1 nm) imaging of extended objects in three-dimensions (3D) has not been possible. A restriction known as the Crowther criterion forces a tradeoff between object size and resolution for 3D reconstructions by tomography. Further, the sub-Angstrom resolution of aberrationcorrected electron microscopes is accompanied by a greatly diminished depth of field, causing regions of larger specimens (> 6 nm) to appear blurred or missing. Here we demonstrate a three-dimensional imaging method that overcomes both these limits by combining through-focal depth sectioning and traditional tilt-series tomography to reconstruct extended objects, with high-resolution, in all three dimensions. The large convergence angle in aberration corrected instruments now becomes a benefit and not a hindrance to higher quality reconstructions. A through-focal reconstruction over a 390 nm 3D carbon support containing over one hundred dealloyed and nanoporous PtCu catalyst particles revealed with sub-nanometer detail the extensive and connected interior pore structure that is created by the dealloying instability. IntroductionWith electron beams smaller than the bond length of hydrogen, aberration-corrected scanning transmission electron microscopes (STEM) can image materials with resolutions below the shortest bond lengths in nature 1 . However, these atomic resolution images are only 2D projections of a specimen. In order to determine the full 3D structure, one must acquire a series of STEM images over a range of specimen tilts 2,3 . Unfortunately, the resolution of a 3D STEM tomogram is degraded by missing information that is a consequence of the restricted specimen tilt range and finite tilt increments. While reconstructions of small objects have been reported at atomic resolution 4,5 , resolution places fundamental limitations to object-size. For larger objects (> 20 nm), the Crowther condition 1,6 discussed below typically limits volumetric resolutions of electron tomography to roughly 1 nm-twenty times worse than the best resolution in 2D projections. In addition, high-resolution (< 1 nm) tomography of general extended objects, to date, has not been possible with aberration-corrected instruments because the depth-of-field (5 -10 nm) of aberration-corrected STEMs is smaller than most objects of interest today 7 . High-resolution 3D reconstruction of extended objects, i.e. those larger than the depth-of-field, requires collecting information beyond a traditional tilt series. Here we present through-focal tomography that combines depth sectioning and traditional tilt-tomography to reconstruct extended objects, with highresolution, in three-dimensions. This combined approach fills in missing 3D information by acquiring a through-focal image series at each specimen tilt (Fig. 1)-decoupling the limiting Crowther relationship between 3D resolution and object size.For traditional (S)TEM tomography the images at every tilt-angle must correspond to a perfect projection of the original object to fulfill the "projection requ...

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Transmission electron microtomography without the “missing wedge” for quantitative structural analysis

Cited by 211 publications

References 21 publications

Three-Dimensional Shapes and Distributions of Long-Period Stacking Ordered Structures in Mg<sub>97</sub>Zn<sub>1</sub>Gd<sub>2</sub> Cast Alloys Characterized by Electron Tomography

Three-Dimensional Shapes and Distributions of Long-Period Stacking Ordered Structures in Mg<sub>97</sub>Zn<sub>1</sub>Gd<sub>2</sub> Cast Alloys Characterized by Electron Tomography

Machine learning as a tool for classifying electron tomographic reconstructions

Breaking the Crowther limit: Combining depth-sectioning and tilt tomography for high-resolution, wide-field 3D reconstructions

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