Guide for Preparation of Flat Composite Panels with Processing Guidelines for Specimen Preparation

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

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Enhancement of Contrast in the CEM and STEM Using Bumpy Specimens and Employing the “Dappled Field” Mode of Operation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052778 ◽

1974 ◽

Vol 32 ◽

pp. 552-553 ◽

Cited By ~ 1

Author(s):

L. Gandolfi ◽

J. Reiffel

Keyword(s):

Operating Mode ◽

Scanning Transmission Electron Microscope ◽

Dark Field ◽

Specimen Preparation ◽

Field Mode ◽

Preparation Methods ◽

Scanning Transmission Electron ◽

Transmission Electron ◽

Mode Of Operation ◽

Scanning Transmission

Calculations have been performed on the contrast obtainable, using the Scanning Transmission Electron Microscope, in the observation of thick specimens. Recent research indicates a revival of an earlier interest in the observation of thin specimens with the view of comparing the attainable contrast using both types of specimens.Potential for biological applications of scanning transmission electron microscopy has led to a proliferation of the literature concerning specimen preparation methods and the controversy over “to stain or not to stain” in combination with the use of the dark field operating mode and the same choice of technique using bright field mode of operation has not yet been resolved.

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Contrast from epitaxially sandwiched macromolecules

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081991 ◽

1978 ◽

Vol 36 (2) ◽

pp. 226-227

Author(s):

M. Talianker ◽

D.G. Brandon

Keyword(s):

Gold Film ◽

Lattice Defect ◽

Gold Foil ◽

Specimen Preparation ◽

Preparation Technique ◽

Resolution Limit ◽

Transmission Electron ◽

Crystal Lattice Defect ◽

Void Effect ◽

Lattice Resolution

A new specimen preparation technique for visualizing macromolecules by conventional transmission electron microscopy has been developed. In this technique the biopolymer-molecule is embedded in a thin monocrystalline gold foil. Such embedding can be performed in the following way: the biopolymer is deposited on an epitaxially-grown thin single-crystal gold film. The molecule is then occluded by further epitaxial growth. In such an epitaxial sandwich an occluded molecule is expected to behave as a crystal-lattice defect and give rise to contrast in the electron microscope.The resolution of the method should be limited only by the precision with which the epitaxially grown gold reflects the details of the molecular structure and, in favorable cases, can approach the lattice resolution limit.In order to estimate the strength of the contrast due to the void-effect arising from occlusion of the DNA-molecule in a gold crystal some calculations were performed.

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The ionic strength dependence of chromatin folding

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081966 ◽

1978 ◽

Vol 36 (2) ◽

pp. 220-221

Author(s):

F. Thoma ◽

TH. Koller

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Ionic Strength ◽

Specimen Preparation ◽

Preparation Technique ◽

Carbon Supports ◽

Ionic Strength Dependence ◽

Chromatin Folding ◽

Strength Dependence ◽

Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

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