Low Voltage Electron Microscopy of Silk Fibers and Films

The aromatic hydrocarbon pentacene is currently under investigation for use as the active layer in electronic devices such as thin film field effect transistors. We have used X-Ray Diffraction (XRD), Electron Diffraction (ED), Low Voltage Electron Microscopy (LVEM), High Resolution Electron Microscopy (HREM) and molecular modeling to investigate the thin film phase of pentacene. We will report the orthorhombic symmetry and lattice parameters of the thin film phase measured experimentally from these techniques. The structure of extended defects such as dislocations and grain boundaries will influence the electrical and mechanical characteristics of the films. Here we show a direct image of an edge dislocation in the thin film phase and discuss the way in which the lattice accommodates the defect.

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Diagnostic Electron Microscopy of Viruses With Low-voltage Electron Microscopes

Journal of Histochemistry & Cytochemistry ◽

10.1369/0022155420929438 ◽

2020 ◽

Vol 68 (6) ◽

pp. 389-402

Author(s):

Lars Möller ◽

Gudrun Holland ◽

Michael Laue

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

High Voltage ◽

Low Voltage ◽

Optical Resolution ◽

Plant Diseases ◽

Voltage Electron ◽

Transmission Electron ◽

High Voltage Transmission ◽

Electron Microscopes

Diagnostic electron microscopy is a useful technique for the identification of viruses associated with human, animal, or plant diseases. The size of virus structures requires a high optical resolution (i.e., about 1 nm), which, for a long time, was only provided by transmission electron microscopes operated at 60 kV and above. During the last decade, low-voltage electron microscopy has been improved and potentially provides an alternative to the use of high-voltage electron microscopy for diagnostic electron microscopy of viruses. Therefore, we have compared the imaging capabilities of three low-voltage electron microscopes, a scanning electron microscope equipped with a scanning transmission detector and two low-voltage transmission electron microscopes, operated at 25 kV, with the imaging capabilities of a high-voltage transmission electron microscope using different viruses in samples prepared by negative staining and ultrathin sectioning. All of the microscopes provided sufficient optical resolution for a recognition of the viruses tested. In ultrathin sections, ultrastructural details of virus genesis could be revealed. Speed of imaging was fast enough to allow rapid screening of diagnostic samples at a reasonable throughput. In summary, the results suggest that low-voltage microscopes are a suitable alternative to high-voltage transmission electron microscopes for diagnostic electron microscopy of viruses.

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Current and future aberration correctors for the improvement of resolution in electron microscopy

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2009.0121 ◽

2009 ◽

Vol 367 (1903) ◽

pp. 3665-3682 ◽

Cited By ~ 49

Author(s):

M. Haider ◽

P. Hartel ◽

H. Müller ◽

S. Uhlemann ◽

J. Zach

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Low Voltage ◽

Spherical Aberration ◽

Chromatic Aberration ◽

Objective Lens ◽

Voltage Electron ◽

System A ◽

Transmission Electron ◽

Correction System

The achievable resolution of a modern transmission electron microscope (TEM) is mainly limited by the inherent aberrations of the objective lens. Hence, one major goal over the past decade has been the development of aberration correctors to compensate the spherical aberration. Such a correction system is now available and it is possible to improve the resolution with this corrector. When high resolution in a TEM is required, one important parameter, the field of view, also has to be considered. In addition, especially for the large cameras now available, the compensation of off-axial aberrations is also an important task. A correction system to compensate the spherical aberration and the off-axial coma is under development. The next step to follow towards ultra-high resolution will be a correction system to compensate the chromatic aberration. With such a correction system, a new area will be opened for applications for which the chromatic aberration defines the achievable resolution, even if the spherical aberration is corrected. This is the case, for example, for low-voltage electron microscopy (EM) for the investigation of beam-sensitive materials, for dynamic EM or for in-situ EM.

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