Image Contrasts in Thin Carbon Films Observed by Shadow Electron Microscopy

1964 ◽  
Vol 35 (5) ◽  
pp. 1652-1653 ◽  
Author(s):  
D. B. Dove
Keyword(s):  
Electron Microscopy ◽  
Carbon Films ◽  
Thin Carbon

Scanning Secondary Electron Microscopy of Myofibrils Using Transmission Techniques

1975 ◽  
Vol 33 ◽  
pp. 556-557
Author(s):  
M. K. Lamvik
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Carbon Films ◽  
Photographic Recording ◽  
Transmission Electron ◽  
Thin Carbon ◽  
The Common ◽  
Scanning Electron ◽  
Better Than ◽  
Cellular Organelles

When observing small objects such as cellular organelles by scanning electron microscopy, it is often valuable to use the techniques of transmission electron microscopy. The common practice of mounting and coating for SEM may not always be necessary. These possibilities are illustrated using vertebrate skeletal muscle myofibrils.Micrographs for this study were made using a Hitachi HFS-2 scanning electron microscope, with photographic recording usually done at 60 seconds per frame. The instrument was operated at 25 kV, with a specimen chamber vacuum usually better than 10-7 torr. Myofibrils were obtained from rabbit back muscle using the method of Zak et al. To show the component filaments of this contractile organelle, the myofibrils were partially disrupted by agitation in a relaxing medium. A brief centrifugation was done to clear the solution of most of the undisrupted myofibrils before a drop was placed on the grid. Standard 3 mm transmission electron microscope grids covered with thin carbon films were used in this study.

Heavy Atom Clusters as Specific Labels

1988 ◽  
Vol 46 ◽  
pp. 238-239
Author(s):  
James F. Hainfeid
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Active Site ◽  
Heavy Atom ◽  
Carbon Films ◽  
Heavy Atoms ◽  
Single Atoms ◽  
Atom Clusters ◽  
Thin Carbon ◽  
Important Milestone

An important milestone in electron microscopy was the first visualization of single atoms in 1970 with the STEM designed by Albert Crewe. This achievement inspired thoughts that single heavy atoms could be used as super high resolution labels of biological structures by, for example, covalently reacting a heavy atom reagent at the active site of an enzyme. Further investigation of heavy atoms on thin carbon films revealed that they hopped about and that this was not solely thermal motion, but beam induced, since cooling the specimen had little effect. Attempts were made to try various heavy atom compounds but alas, these all behaved similarly, with about 10% of the atoms moving 3-10 Å on successive scans. A gallant effort by M. Beer to sequence DNA using heavy atom base specific labels befell similar problems where the motion of the label prevented high resolution coordinates from being measured.

Surface analysis of thin carbon films used as supports for electron microscopy

1988 ◽  
Vol 12 (6) ◽  
pp. 359-360
Author(s):  
R. Schlögl ◽  
B. Tesche ◽  
G. Weinberg
Keyword(s):  
Electron Microscopy ◽  
Surface Analysis ◽  
Carbon Films ◽  
Thin Carbon

Electron microscopy of vapor phase deposited diamond

1990 ◽  
Vol 5 (4) ◽  
pp. 801-810 ◽  
Author(s):  
B.E. Williams ◽  
H.S. Kong ◽  
J.T. Glass
Keyword(s):  
Electron Microscopy ◽  
Twin Boundary ◽  
Microwave Plasma ◽  
Defect Density ◽  
Diamond Films ◽  
Carbon Films ◽  
Hydrogen Gas ◽  
Twin Boundaries ◽  
Lattice Image ◽  
Thin Carbon

Thin carbon films grown from a low pressure methane-hydrogen gas mixture by microwave plasma enhanced CVD have been examined by electron microscopy. Previously reported transmission electron microscopy (TEM) of the diamond films has shown that the majority of diamond crystals have a very high defect density comprised of {111} twins, {111} stacking faults, and dislocations. In this study, high resolution electron microscopy (HREM) has been utilized to lattice image individual defects in these polycrystalline diamond films. Interpretation of the images from these defects is not trivial and reported image simulations have been utilized to understand further these defects. Fivefold multiply twinned particles have also been examined and it was found that the 7.5° misfit present in such particles has been accommodated at the twin boundaries rather than by elastic deformation. This creates a twin boundary coincident with a low angle grain boundary which has been termed a “tilted twin boundary”. The density of defects in these particles is generally high; however, a dramatic reduction in the defect density near the twin boundaries was observed. This defect reduction is significant because if its origin can be determined, this information may be useful in producing higher quality diamond films.

Thin Carbon Film Areas Produced under Controlled Conditions

1973 ◽  
Vol 31 ◽  
pp. 78-79
Author(s):  
Nabil Rizk ◽  
Irwin Bendet
Keyword(s):  
Electron Microscopy ◽  
Carbon Film ◽  
High Resolution Electron Microscopy ◽  
Carbon Films ◽  
The Other ◽  
Biological Macromolecules ◽  
Resolution Electron ◽  
Thin Carbon ◽  
Carbon Substrates ◽  
Thin Carbon Film

The need for increasingly thin films to attain the ultimate in high resolution electron microscopy has seen the development of carbon substrates for the support of biological macromolecules. To date, the procedures employed for producing such substrates have involved either the floating off of carbon films from mica onto water and picking them up on EM grids or the deposition of carbon upon plastic covered grids, the plastic of which is subsequently dissolved away. We have now developed an efficient technique, unencumbered by the difficulties associated with the other procedures, for producing well delineated areas of thin carbon film of measurable thickness. In this procedure we utilize silk threads, about 15 microns in diameter, stretched across an adjustable frame having a 1” square opening (Fig. 1).

Object Wave Determination by Single-Sideband Methods

1973 ◽  
Vol 31 ◽  
pp. 266-267
Author(s):  
Kenneth H. Downing ◽  
Benjamin M. Siegel
Keyword(s):  
Phase Shift ◽  
Carbon Films ◽  
Object Wave ◽  
Electron Wave ◽  
Phase Object ◽  
Heavy Atoms ◽  
Single Sideband ◽  
Thin Carbon ◽  
Additional Phase Shift ◽  
Additional Phase

Under the “weak phase object” approximation, the component of the electron wave scattered by an object is phase shifted by π/2 with respect to the unscattered component. This phase shift has been confirmed for thin carbon films by many experiments dealing with image contrast and the contrast transfer theory. There is also an additional phase shift which is a function of the atomic number of the scattering atom. This shift is negligible for light atoms such as carbon, but becomes significant for heavy atoms as used for stains for biological specimens. The light elements are imaged as phase objects, while those atoms scattering with a larger phase shift may be imaged as amplitude objects. There is a great deal of interest in determining the complete object wave, i.e., both the phase and amplitude components of the electron wave leaving the object.

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

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