Chemical Analysis and Structural Investigations of Sodium- and Lanthanide Ion-Exchanged Beta-Aluminas

1978 ◽

Vol 36 (2) ◽

pp. 170-171

Author(s):

Mitsuo Ohtsuki ◽

Michael Sogard

Keyword(s):

Electron Microscope ◽

Phase Contrast ◽

Image Interpretation ◽

Density Lipoprotein ◽

Biological Macromolecules ◽

Contrast Effects ◽

Biological Structure ◽

Electron Microscopic ◽

Structural Investigations ◽

Staining Techniques

Structural investigations of biological macromolecules commonly employ CTEM with negative staining techniques. Difficulties in valid image interpretation arise, however, due to problems such as variability in thickness and degree of penetration of the staining agent, noise from the supporting film, and artifacts from defocus phase contrast effects. In order to determine the effects of these variables on biological structure, as seen by the electron microscope, negative stained macromolecules of high density lipoprotein-3 (HDL3) from human serum were analyzed with both CTEM and STEM, and results were then compared with CTEM micrographs of freeze-etched HDL3. In addition, we altered the structure of this molecule by digesting away its phospholipid component with phospholipase A2 and look for consistent changes in structure.

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Aspects of microanalysis in a transmission electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109690 ◽

1978 ◽

Vol 36 (1) ◽

pp. 510-511

Author(s):

R. Sinclair ◽

B.E. Jacobson

Keyword(s):

Grain Size ◽

Electron Beam ◽

Electron Microscope ◽

Chemical Analysis ◽

Transmission Electron Microscope ◽

Vapor Deposition ◽

Critical Currents ◽

X Ray ◽

Fine Grain ◽

Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

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A tilting high temperature gas reaction chamber for the JEM 7A T.E.M.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107496 ◽

1978 ◽

Vol 36 (1) ◽

pp. 70-71

Author(s):

Brian L. Rhoades

Keyword(s):

Cross Section ◽

Reaction Chamber ◽

Objective Lens ◽

Reduced Cross Section ◽

Cross Sectional ◽

Structural Investigations ◽

Transmission Electron ◽

Dynamic Experiments ◽

Successful Design ◽

Thermocouple Junction

A gas reaction chamber has been designed and constructed for the JEM 7A transmission electron microscope which is based on a notably successful design by Hashimoto et. al. but which provides specimen tilting facilities of ± 15° aboutany axis in the plane of the specimen.It has been difficult to provide tilting facilities on environmental chambers for 100 kV microscopes owing to the fundamental lack of available space within the objective lens and the scope of structural investigations possible during dynamic experiments has been limited with previous specimen chambers not possessing this facility.A cross sectional diagram of the specimen chamber is shown in figure 1. The specimen is placed on a platinum ribbon which is mounted on a mica ring of the type shown in figure 2. The ribbon is heated by direct current, and a thermocouple junction spot welded to the section of the ribbon of reduced cross section enables temperature measurement at the point where localised heating occurs.

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Integrated morphometrical and electron energy loss image analysis in cytochemistry

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153981 ◽

1989 ◽

Vol 47 ◽

pp. 402-403

Author(s):

W.C. de Bruijn ◽

A.A.W. de Jong ◽

C.W.J. Sorber

Keyword(s):

Image Analysis ◽

Acid Phosphatase ◽

Chemical Analysis ◽

Active Form ◽

List Type ◽

Type Number ◽

Enzyme Cytochemistry ◽

Related Data ◽

Endogenous Peroxidase ◽

Electron Energy Loss

One aspect of enzyme cytochemistry is, whether all macrophage lysosomal hydrolytical enzymes are present in an active form, or are activated upon stimulation. Integrated morphometrical and chemical analysis has been chosen as a tool to illucidate that cytochemical problem. Mouse peritoneal resident macrophages have been used as a model for this complicated integration of morphometrical and element-related data. Only aldehyde-fixed cells were treated with three cytochemical reactions to detect different enzyme activities within one cell (for details see [1,2]). The enzyme-related precipitates anticipated to be differentiated, were:(1).lysosomal barium and sulphur from aryl sulphatase activity,(2).lysosomal cerium and phosphate from acid phosphatase activity and(3).platinum/di-amino-benzidine( D A B) complex from endogenous peroxidase activity.

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Microdomains in BaFeO3-y (0.35 < y < 0.50)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177039 ◽

1990 ◽

Vol 48 (4) ◽

pp. 780-781

Author(s):

M. Vallet-Regí ◽

M. Parras ◽

J.M. González-Calbet ◽

J.C. Grenier

Keyword(s):

Electron Diffraction ◽

Chemical Analysis ◽

Monoclinic Phase ◽

Orthorhombic Phase ◽

Total Iron ◽

Zone Axis ◽

Electron Micrograph ◽

X Ray Diffraction ◽

X Ray ◽

Compositional Variations

BaFeO3-y compositions (0.35<y<0.50) have been investigated by means of electron diffraction and microscopy to resolve contradictory results from powder X-ray diffraction data.The samples were obtained by annealing BaFeO2.56 for 48 h. in the temperature range from 980°C to 1050°C . Total iron and barium in the samples were determined using chemical analysis and gravimetric methods, respectively.In the BaFeO3-y system, according to the electron diffraction and microscopy results, the nonstoichiometry is accommodated in different ways as a function of the composition (y):In the domain between BaFeO2.5+δBaFeO2.54, compositional variations are accommodated through the formation of microdomains. Fig. la shows the ED pattern of the BaFeO2.52 material along thezone axis. The corresponding electron micrograph is seen in Fig. 1b. Several domains corresponding to the monoclinic BaFeO2.50 phase, intergrow with domains of the orthorhombic phase. According to that, the ED pattern of Fig. 1a, can be interpreted as formed by the superposition of three types of diffraction maxima : Very strong spots corresponding to a cubic perovskite, a set of maxima due to the superposition of three domains of the monoclinic phase along [100]m and a series of maxima corresponding to three domains corresponding to the orthorhombic phase along the [100]o.

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