Structural variations and transformation behavior of the Al68Cu11Co21 decagonal phase

1994 ◽  
Vol 9 (11) ◽  
pp. 2899-2906 ◽  
Author(s):  
B. Grushko ◽  
R. Wittmann ◽  
K. Urban
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transformation Kinetics ◽  
Transformation Behavior ◽  
Structural Variations ◽  
Ordered Structures ◽  
Decagonal Phase ◽  
Prolonged Annealing ◽  
Electron Diffractograms ◽  
Scanning Electron

The Al68Cu11Co21 decagonal phase was studied after annealing at 1000 °C for 24-760 h by transmission and scanning electron microscopy. The strong superstructure odd-n reflections in the [1,-2, 1, 0, 0] electron diffractograms were stable under annealing up to about 40 h. As a possible origin of the increased intensities of the odd-n reflections the formation of vacancy-ordered structures is discussed. The structure was modified by prolonged annealing. In several annealed samples a dense net of extra reflections overlapping the quasiperiodic reflections was observed. This observation was explained as an indication of the formation of metastable states during cooling. Differently ordered decagonal structures exhibited different transformation kinetics during cooling from high temperatures.

A study of the high-Cu Al–Cu–Co decagonal phase

1993 ◽  
Vol 8 (7) ◽  
pp. 1473-1476 ◽  
Author(s):  
B. Grushko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Diffraction ◽  
Diffuse Scattering ◽  
Nonequilibrium State ◽  
Zone Axis ◽  
Decagonal Phase ◽  
Diffraction Patterns ◽  
Scanning Electron

The decagonal phase was studied by transmission and scanning electron microscopy in an Al62Cu24Co14 alloy annealed at 550–850 °C. The electron diffraction patterns of the decagonal phase exhibited weak quasiperiodic odd-n reflections in the [1-2100] zone axis corresponding to the equilibrated structure. The relative intensities of these reflections were significantly lower in the Al62Cu24Co14 than in the Al68Cu11Co21 decagonal phase. Diffuse scattering observed previously at the same positions can be related to a nonequilibrium state of the decagonal phase.

An Al13Co4 phase in the Al–Cu–Co alloy system

1992 ◽  
Vol 7 (5) ◽  
pp. 1100-1103 ◽  
Author(s):  
B. Grushko ◽  
Ch. Freiburg
Keyword(s):  
Electron Microscopy ◽  
Phase Diagram ◽  
Scanning Electron Microscopy ◽  
Liquid Phase ◽  
Alloy System ◽  
Homogeneity Region ◽  
X Ray ◽  
Decagonal Phase ◽  
Scanning Electron

A part of the Al–Cu–Co phase diagram adjacent to the Al13Co4 composition was studied at 800 °C by scanning electron microscopy and x-ray diffractometry. The homogeneity region of the Al13Co4 phase was found to extend up to 6 at. % Cu. At 800 °C this phase is in equilibrium with Al(Co, Cu), Al5Co2, Al9Co2, the decagonal phase, and a liquid phase. The existence of the Y-phase and Al3Co was not confirmed at this temperature.

scholarly journals Morphological differentiation and distribution of non-glandular and glandular trichomes on Dracocephalum moldavicum L. shoots

2012 ◽  
Vol 63 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Elżbieta Weryszko-Chmielewska ◽  
Marta Dmitruk
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Glandular Trichomes ◽  
Morphological Differentiation ◽  
Structural Variations ◽  
Abaxial Surface ◽  
The Rich ◽  
Trichome Types ◽  
Scanning Electron

The structure, micromorphology and distribution of trichomes on <i>Dracocephalum moldavicum</i> L. shots were investigated using light and scanning electron microscopy (SEM). There were distinguished 3 types of non-glandular trichomes, 3 types of glandular trichomes and papillae of the osmophore in the epidermis of the corolla. The highest density of non-glandular and glandular trichomes was found on the abaxial surface of the calyx, on bracts and in the upper part of the stem. Structural variations in the head and stalk of long glandular trichomes were demonstrated. The dimensions of particular types of trichomes are given in the present paper. Differences in the structure of the trichomes of this species are presented, compared to literature data. The micromorphology of particular trichome types is documented in numerous photographs showing the rich ornamentation of the cuticle of non-glandular trichomes.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Spontaneous Cataract in Nude Athymic Mice

1977 ◽  
Vol 35 ◽  
pp. 512-513
Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nude Mouse ◽  
Cellular Immunity ◽  
Phosphate Buffer ◽  
Osmium Tetroxide ◽  
Athymic Mice ◽  
Transmission Microscopy ◽  
Mouse Lens ◽  
Scanning Electron

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.

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