scholarly journals Phase transitions in fullerene (C60) and the related microstructure: a study by electron diffraction and electron microscopy

1992 ◽  
Vol 96 (18) ◽  
pp. 7424-7430 ◽  
Author(s):  
G. Van Tendeloo ◽  
C. Van Heurck ◽  
J. Van Landuyt ◽  
S. Amelinckx ◽  
M. A. Verheijen ◽  
...  
1983 ◽  
Vol 21 ◽  
Author(s):  
D. Colaitis ◽  
Van Dyck ◽  
C. Conde-Amiano ◽  
S. Amelinckx

ABSTRACTSome systems show continuous and reversible phase transitions which are characterised by the appearance of irrational sunerlattice reflections with a position that shifts continuously and reversibly with temperature. This diffraction feature is not necessarily caused by a deformation modulation but can also originate from the reneated occurrence of planar defects with a variable “average” periodicity. The planar defects can be of different type (e.g. planes of different composition, antiphase boundaries, twin planes) as shown for the systems Ni3+xTe2, Cu3−xTe2, Cu2−S, mPbS-nBi2S3 ( > 2) and Cu 0.75VS2, using electron-microscopy and electron diffraction.


1975 ◽  
Vol 30 (1) ◽  
pp. 299-314 ◽  
Author(s):  
J. van Landuyt ◽  
G. van Tendeloo ◽  
S. Amelinckx

Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.


Author(s):  
G. G. Hembree ◽  
M. A. Otooni ◽  
J. M. Cowley

The formation of oxide structures on single crystal films of metals has been investigated using the REMEDIE system (for Reflection Electron Microscopy and Electron Diffraction at Intermediate Energies) (1). Using this instrument scanning images can be obtained with a 5 to 15keV incident electron beam by collecting either secondary or diffracted electrons from the crystal surface (2). It is particularly suited to studies of the present sort where the surface reactions are strongly related to surface morphology and crystal defects and the growth of reaction products is inhomogeneous and not adequately described in terms of a single parameter. Observation of the samples has also been made by reflection electron diffraction, reflection electron microscopy and replication techniques in a JEM-100B electron microscope.A thin single crystal film of copper, epitaxially grown on NaCl of (100) orientation, was repositioned on a large copper single crystal of (111) orientation.


Author(s):  
G. Timp ◽  
L. Salamanca-Riba ◽  
L.W. Hobbs ◽  
G. Dresselhaus ◽  
M.S. Dresselhaus

Electron microscopy can be used to study structures and phase transitions occurring in graphite intercalations compounds. The fundamental symmetry in graphite intercalation compounds is the staging periodicity whereby each intercalate layer is separated by n graphite layers, n denoting the stage index. The currently accepted model for intercalation proposed by Herold and Daumas assumes that the sample contains equal amounts of intercalant between any two graphite layers and staged regions are confined to domains. Specifically, in a stage 2 compound, the Herold-Daumas domain wall model predicts a pleated lattice plane structure.


Author(s):  
Robert M. Glaeser ◽  
Bing K. Jap

The dynamical scattering effect, which can be described as the failure of the first Born approximation, is perhaps the most important factor that has prevented the widespread use of electron diffraction intensities for crystallographic structure determination. It would seem to be quite certain that dynamical effects will also interfere with structure analysis based upon electron microscope image data, whenever the dynamical effect seriously perturbs the diffracted wave. While it is normally taken for granted that the dynamical effect must be taken into consideration in materials science applications of electron microscopy, very little attention has been given to this problem in the biological sciences.


Sign in / Sign up

Export Citation Format

Share Document