A Technique For The Rapid Determination of the Contrast Transfer Characteristics of an Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 278-279 ◽  
Author(s):  
William Krakow ◽  
Kenneth H. Downing ◽  
Benjamin M. Siegel
Keyword(s):  
Rapid Determination ◽  
Carbon Film ◽  
Large Angle ◽  
Objective Lens ◽  
Transfer Characteristics ◽  
Thin Carbon ◽  
Family Of Curves ◽  
Relative Contrast ◽  
Thin Carbon Film ◽  
The Fourier Transform

A focal series of a thin carbon film in bright-field phase contrast has been used by Thon to obtain a family of curves that represent the contrast transfer characteristics of a particular objective lens as a function of the defocus value. The thin carbon film is assumed to be a weak phase object, and the light optical diffractogram gives the Fourier transform of each micrograph from which the relative contrast at each spatial frequency can be obtained for the corresponding amount of defocus.We have obtained the equivalent information from a single electron micrograph of a thin carbon film specimen tilted at a large angle (65°), see Fig. 1.

Hydrated form of some clay minerals observed using a film sealed environmental cell

1978 ◽  
Vol 36 (1) ◽  
pp. 72-73
Author(s):  
N. Kohyama ◽  
K. Fukushima ◽  
A. Fukami
Keyword(s):  
Clay Minerals ◽  
Morphological Changes ◽  
Carbon Film ◽  
Electron Microscopic Observation ◽  
Adsorbed Water ◽  
Electron Microscopic ◽  
Hydrated Form ◽  
Thin Carbon ◽  
Environmental Cell ◽  
Thin Carbon Film

Since the interlayer or adsorbed water of some clay minerals are quite easily dehydrated in dried air, in vacuum, or at moderate temperatures even in the atmosphere, the hydrated forms have not been observed by a conventional electron microscope(TEM). Recently, specific specimen chambers, “environmental cells(E.C.),” have been developed and confirmed to be effective for electron microscopic observation of wet specimen without dehydration. we observed hydrated forms of some clay minerals and their morphological changes by dehydration using a TEM equipped with an E.C..The E.C., equipped with a single hole copper-microgrid sealed by thin carbon-film, attaches to a TEM(JEM 7A) with an accelerating voltage 100KV and both gas pressure (from 760 Torr to vacuum) and relative humidity can be controlled. The samples collected from various localities in Japan were; tubular halloysite (l0Å) from Gumma Prefecture, sperical halloysite (l0Å) from Tochigi Pref., and intermediate halloysite containing both tubular and spherical types from Fukushima Pref..

Alkaline Dissociation Products of Lumbricus Terrestris Hemoglobin Viewed with the STEM

1981 ◽  
Vol 39 ◽  
pp. 434-435
Author(s):  
O. H. Kapp ◽  
M. Ohtsuki ◽  
N. Robin ◽  
S. N. Vinogradov ◽  
A. V. Crewe
Keyword(s):  
Carbon Film ◽  
Lumbricus Terrestris ◽  
Uranyl Acetate ◽  
Acetate Solution ◽  
Oxygen Carriers ◽  
Complex Molecules ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
Multiple Copies ◽  
Hill Coefficients

Annelid extracellular hemoglobins are among the largest known proteins (M.W = 3.9 x 106), and together with the hemocyanins are the largest known oxygen carriers. They display oxygen affinities generally higher than those o vertebrate hemoglobins with Hill coefficients ranging from slightly higher than unity to values as high as 5-6. These complex molecules are composed of multiple copies of as many as six different polypeptides and posse: approximately 150 hemes per molecule.The samples were diluted to 100-200 μg/ml with distilled water just before application to a thin carbon film (∽15 Å thick). One percent (w/v) uranyl acetate solution was used for negative staining for 2 minutes and dried in air. The specimens were examined with the high resolution STEM. Their general appearance is that of a hexagonal bilayer (Fig. 1), each layer consisting of six spheroidal subunits. The corner to corner hexagonal dimensic is approximately 300 Å and the bilayer thickness approximately 200 Å.

Application of electron holography to material science studies on magnetic domain states of small particles

1993 ◽  
Vol 51 ◽  
pp. 1028-1029
Author(s):  
T. Hirayama ◽  
Q. Ru ◽  
T. Tanji ◽  
A. Tonomura
Keyword(s):  
Magnetic Field ◽  
Material Science ◽  
Science Studies ◽  
Phase Distribution ◽  
Carbon Film ◽  
Objective Lens ◽  
Electron Holography ◽  
Transform Method ◽  
Transmission Electron ◽  
Thin Carbon

The observation of small magnetic materials is one of the most important applications of electron holography to material science, because interferometry by means of electron holography can directly visualize magnetic flux lines in a very small area. To observe magnetic structures by transmission electron microscopy it is important to control the magnetic field applied to the specimen in order to prevent it from changing its magnetic state. The easiest method is tuming off the objective lens current and focusing with the first intermediate lens. The other method is using a low magnetic-field lens, where the specimen is set above the lens gap.Figure 1 shows an interference micrograph of an isolated particle of barium ferrite on a thin carbon film observed from approximately [111]. A hologram of this particle was recorded by the transmission electron microscope, Hitachi HF-2000, equipped with an electron biprism. The phase distribution of the object electron wave was reconstructed digitally by the Fourier transform method and converted to the interference micrograph Fig 1.

Thin carbon film deposition using energetic ions of a dense plasma focus

1997 ◽  
Vol 226 (3-4) ◽  
pp. 212-216 ◽  
Author(s):  
Chhaya R. Kant ◽  
M.P. Srivastava ◽  
R.S. Rawat
Keyword(s):  
Plasma Focus ◽  
Dense Plasma ◽  
Carbon Film ◽  
Film Deposition ◽  
Dense Plasma Focus ◽  
Energetic Ions ◽  
Thin Carbon ◽  
Thin Carbon Film

Effects of Amorphous Carbon Films on the Performance of Porous Silicon Electroluminescence

2002 ◽  
Vol 737 ◽  
Author(s):  
Bernard Gelloz ◽  
Nobuyoshi Koshida
Keyword(s):  
Porous Silicon ◽  
Amorphous Carbon ◽  
Chemical Stability ◽  
Indium Tin Oxide ◽  
Carbon Film ◽  
Carbon Films ◽  
Positive Effects ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
The Stability

ABSTRACTEfficient electroluminescence (EL) is obtained at low operating voltages (<3 V) from n+-type silicon- electrochemically oxidized thin nanocrystalline porous silicon (PS)-amorphous carbon-Indium tin oxide (ITO) junctions. The effects of a few nanometer thick amorphous carbon film between PS and ITO on the EL characteristics have been investigated. The carbon film enhances the stability. The EL efficiency is improved due to a reduction of current density and an increase in EL intensity. In addition, the reproducibility from device to device is very much improved by the carbon film. The enhancement in stability should originate from the capping of PS by the carbon film and the high chemical stability of carbon and Si-C bonds, which should prevent PS oxidation. The carbon film acts as an efficient buffer layer between PS and ITO, resulting in enhanced mechanical, electrical and chemical stability of the top contact and providing high reproducibility. The thin carbon film has only positive effects on all the EL characteristics. This is a very important step towards application.

A Study of Contamination Caused by a Very Narrow Election Beam

1974 ◽  
Vol 32 ◽  
pp. 560-561
Author(s):  
Warren A. Knox
Keyword(s):  
Carbon Film ◽  
Circular Cone ◽  
Scanning Beam ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
Better Than

Our study of contamination spots was done using the JEM-100B microscope in both the scanning and conventional modes. A very narrow scanning beam known to give a resolution of better than 35Å was focused, with scanning coils deactivated, onto the surface of a thin carbon film for various periods of time. The resulting contamination spots were then shadowed with gold at an angle of 30°, and imaged conventionally. The diameters of the spots were measured directly while the heights were calculated from the shadow lengths. The volumes were then calculated considering the spot to be the frustum of a right circular cone with minor diameter the known resolution of the beam, and major diameter the measured diameter.

Processing of STEM Images of Unstained Tropomyosin Magnesium Paracrystals

1977 ◽  
Vol 35 ◽  
pp. 82-83
Author(s):  
S.D. Golladay
Keyword(s):  
Magnetic Tape ◽  
Sampling Rate ◽  
Carbon Film ◽  
Region Of Interest ◽  
Dark Field ◽  
Bright Field ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
Annular Detector ◽  
Scan Data

The banding patterns of unstained tropomyosin magnesium paracrystals have been observed in a STEM at 30 kV. The microscope is interfaced to a computer so that both bright field and dark field (annular detector) signals can be stored on magnetic tape. The data acquisition system imposes constraints on the image sampling rate and on the maximum number of picture elements per frame, but has the substantial advantage of eliminating the need for careful film processing and densitometry for quantitative microscopy. The system is extremely helpful when first scan images of relatively thick objects on a thin carbon film are desired. In this situation, the operator cannot adjust the gain and bias of the video signal properly until he has already scanned the specimen. However, first scan data stored on magnetic tape can be replayed with bias and gain adjusted digitally to provide the best display of any specified region of interest in the image. Figure 1 shows such a replay of the bright field (IB) and dark field (1A) images of the paracrystal which was analyzed. The specimen was fixed and air dried but unstained.

A New Method for Single Atom Specimen Preparation

1975 ◽  
Vol 33 ◽  
pp. 224-225
Author(s):  
W. Chiu ◽  
R. M. Glaeser ◽  
S. Prussin
Keyword(s):  
Unit Area ◽  
Carbon Film ◽  
Gold Atom ◽  
High Resolution Electron Microscopy ◽  
Carbon Films ◽  
Single Atom ◽  
Specimen Preparation ◽  
Electron Microscopic ◽  
Thin Carbon ◽  
Thin Carbon Film

A reliable method of confirming that one is able to produce single atom images in high resolution electron microscopy is to make a comparison of the number of atoms per unit area that is seen by the electron microscopic observations and the number per unit area as determined by a separate experimental technique of high accuracy. This report presents a method of preparinga specimen composed of a low distribution of gold atoms (ca. 1 atom/104 Å2) sandwiched between two ultra-thin carbon films, and also a method of measuring the gold atom density in the specimen by neutron activation analysis.The specimen was prepared by evaporation onto a freshly cleaved mica substrate in a vacuum evaporator, as shown in Figure 1. One side of the vacuum chamber was used to prepare a thin carbon film according to the method of Williams and Glaeser (1972), and the other side was used to evaporate the gold atoms from a molybdenum strip, which had a micro-quantity of gold deposited on a 1 cm2 surface area from a previous evaporation.

Incoherent illumination method with conventional electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 174-175
Author(s):  
Fumio Nagata ◽  
Tsuyoshi Matsuda ◽  
Tsutomu Komoda ◽  
Kiyoshi Hama
Keyword(s):  
Electron Microscope ◽  
Contrast Effect ◽  
Phase Contrast ◽  
Carbon Film ◽  
Large Angle ◽  
Image Resolution ◽  
Experimental Investigations ◽  
Objective Lens ◽  
Glancing Angle ◽  
Strong Excitation

When fine details of thin films are observed, the image are generally composed of both amplitude and phase contrast. The image resolution is sometimes limited by the granular background noise of supporting film which is due to the phase contrast effect by fairly coherent illumination(CI).In the present work, incoherent illumination(ICI) method has been studied to avoid the phase contrast effect using a conventional electron microscope(Hitachi HU-12A).The ICI method was made by enlarging the illumination angle(β) to be equivalent to the glancing angle(α=1.4x10-2 radians) of objective aperture. The large angle illumination was achieved by the strong excitation of an objective lens.At first, the properties of phase contrast in ICI image were studied as functions of beam divergence angle and defocus using a carbon film. Both analytical and experimental investigations show that the granular noise in a phase contrast image decreases as β is increased from l×l0-4 to l×l0-2radians.

Sign in / Sign up

Export Citation Format

Share Document