Electron Microscopic Study of Long Period Modulated Structures with Continuously Variable Periodicity

1983 ◽  
Vol 21 ◽  
Author(s):  
D. Colaitis ◽  
Van Dyck ◽  
C. Conde-Amiano ◽  
S. Amelinckx
Keyword(s):  
Electron Microscopy ◽  
Phase Transitions ◽  
Electron Diffraction ◽  
Microscopic Study ◽  
Electron Microscopic ◽  
Antiphase Boundaries ◽  
Planar Defects ◽  
Long Period ◽  
Modulated Structures ◽  
Reversible Phase

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.

Structure refinements in M7C3 (M=Cr,Fe) carbide

1990 ◽  
Vol 48 (4) ◽  
pp. 484-485
Author(s):  
A.Q. He ◽  
H.Q. Ye ◽  
G. van Tendeloo ◽  
K.H. Kuo
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Crystal Defects ◽  
Hrem Image ◽  
Beam Direction ◽  
Electron Microscopic ◽  
Antiphase Boundaries ◽  
Planar Defects ◽  
Contrast Method ◽  
Diffraction Patterns

The crystal defects in M7C3 (M=Cr,Fe) have been investigated by electron microscopy. The results show that there exist a lot of planar defects such as antiphase boundaries, and twin boundaries in it. According to Rouault et al., the structure of Cr7C3 is orthorhombic but based on a hexagnoal sublattice with a=0.701, b=1.214, c=0.452nm, i. e b/a=. For a perfect hexagonal sublattice the defects in {110} would be invisible both in electron diffraction patterns and in electron microscopic images when detected exactly along [001], So, these defects in M7C3 were observed by diffracted contrast method in which electron beam tilts a little from c axis or by HREM image with special beam direction but not [001] zone.e have found however in our sample the strcture of the M7C3 is probably orthorhombic but b/a≠3, such that no hexagnoal sublattice. A structure based on a non-hexagnoal lattice which produces twining is no longer invisble along [001] by HREM.Powder of M7C3 carbide was extracted by electricity chemistry from a cast-iron superalloy. The composition (wt) is: Cr-24.94%, Ni-20%, Mn-0.43%, Si-1.42%, S-0.017%, P-0.017%, C-0.41%. It was collected by carbon grid, and examined in JEOL 200CX.

Vesicular system associated with spermiogenesis of bullfrog

1987 ◽  
Vol 45 ◽  
pp. 818-819
Author(s):  
K. C. Liu ◽  
S. F. Tsay
Keyword(s):  
Electron Microscopy ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Reproductive System ◽  
Seminiferous Tubule ◽  
Rana Catesbeiana ◽  
Routine Procedure ◽  
Electron Microscopic ◽  
Twisted Tubules ◽  
Electron Lucent

In the histologic and electron microscopic study of the male reproductive system of bullfrog, Rana catesbeiana, a vesicular system associated with spermiogenesis was observed. It appeared in the lumenal space of the seminiferous tubule (Fig. 1), in the heads of spermatids (Fig. 2), associated with the chromatins of the spermatid (Fig. 4). As deduced from sections, this vesicular system consisted of vesicles of various size or a large group of waving and twisted tubules (Fig. 3), After routine procedure of treatment for electron microscopy, the lumens of both of the vesicles and tubules were electron lucent.In human, vesicles and vesicular system associated with reproductive cell and tissue were reported. In abnormal spermiogenesis, flower-like body, actually vesicles, and giant vesicle associated with the head of spermatid were observed. In both cases the number of vesicle was limited from a single one to a few.

scholarly journals Probing planar defects in nanoparticle superlattices by 3D small-angle electron diffraction tomography and real space imaging

Nanoscale ◽  
2014 ◽  
Vol 6 (22) ◽  
pp. 13803-13808 ◽  
Author(s):  
Arnaud Mayence ◽  
Dong Wang ◽  
German Salazar-Alvarez ◽  
Peter Oleynikov ◽  
Lennart Bergström
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Real Space ◽  
Diffraction Tomography ◽  
Planar Defects ◽  
Pd Nanoparticle ◽  
Transmission Electron ◽  
Nanoparticle Superlattices ◽  
Microscopy Techniques

Planar defects in Pd nanoparticle superlattices were revealed by a combination of real and reciprocal space transmission electron microscopy techniques. 3D electron diffraction tomography was extended to characterize mesoscale imperfections.

scholarly journals Electron-microscopic study of measles virus in lymphocytes of affected children

1973 ◽  
Vol 71 (3) ◽  
pp. 447-451 ◽  
Author(s):  
H. K. Narang
Keyword(s):  
Electron Microscopy ◽  
Incubation Period ◽  
Microscopic Study ◽  
Cell Lines ◽  
Electron Microscopic Study ◽  
Inclusion Bodies ◽  
Measles Virus ◽  
Internal Diameter ◽  
Electron Microscopic ◽  
Different Types

SUMMARYTwo different types of inclusion bodies have been found by electron-microscopy in the cytoplasm of sectioned lymphocytes from children infected with measles.The first is tubular, 18 nm. internal diameter, embedded in osmiophilic material, and is found during the incubation period. It is not thought to be specific for measles, and is probably identical with structures recently reported in HEp-2 cell lines and tumour tissue.The second type is less obviously tubular and morphologically resembles measles nucleocapsid. This was found only after the rash had appeared.

Characterization Of APB's In GaP

1996 ◽  
Vol 442 ◽  
Author(s):  
Dov Cohen ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Convergent Beam Electron Diffraction ◽  
Antiphase Boundaries ◽  
Beam Electron ◽  
Transmission Electron ◽  
Convergent Beam ◽  
Crystallographic Orientations

AbstractAntiphase boundaries in GaP crystals epitactically grown on Si (001) have been characterized using transmission electron microscopy. Convergent-beam electron diffraction was used to identify the antiphase-related grains. The antiphase boundaries were observed to adopt facets parallel to specific crystallographic orientations. Furthermore, stacking-fault-like contrast was observed along the interface suggesting that the domains may be offset from one another by a rigid-body lattice translation.

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