New Insights into the Generation Mechanism of Quasicrystal by the Surface Reaction Between Ultrafine Particles and Deposited Clusters

2003 ◽  
Vol 10 (02n03) ◽  
pp. 461-466 ◽  
Author(s):  
O. Kido ◽  
C. Kaito ◽  
Y. Saito
Keyword(s):  
Thin Film ◽  
Electron Microscope ◽  
Ultrafine Particles ◽  
Surface Reaction ◽  
Generation Mechanism ◽  
Uniform Thickness ◽  
Microscope Images ◽  
Diffusion Rates ◽  
Al Thin Film ◽  
And Diffusion

On heating Mn-deposited Al particles (Mn–Al specimen) at 300°C, diffraction spots due to a Al86Mn14 quasicrystal appeared, in addition to those due to Al6Mn alloy. On heating a specimen of the Al-deposited Mn particles (Al–Mn specimen), Al50Mn50 alloy was formed. Neither the quasicrystal nor Al6Mn phases appeared. The electron microscope images of the Mn–Al specimen showed the existence of void clusters in the Al particles. This indicates that the alloys and the quasicrystals were produced by the diffusion of Al atoms to the Mn clusters. In the case of the Al–Mn specimen, the surface of Mn particles was covered with an Al thin film of uniform thickness. The surface Al layer changed to Al50Mn50 alloy. These results indicate that the diffusion direction of atoms and diffusion rates are different between Mn–Al and Al–Mn systems.

The surface reaction and diffusion of NO 2 in lead phthalocyanine thin film

1999 ◽  
Vol 342 (1-2) ◽  
pp. 238-243 ◽  
Author(s):  
Y.H. Ju ◽  
C. Hsieh ◽  
C.J. Liu
Keyword(s):  
Thin Film ◽  
Surface Reaction ◽  
And Diffusion ◽  
Reaction And Diffusion

Phase formation and diffusion in V/Al thin film couples prepared under varying deposition conditions

1984 ◽  
Vol 114 (3) ◽  
pp. 271-284 ◽  
Author(s):  
T.G. Finstad ◽  
G. Salomonsen ◽  
N. Norman ◽  
J.S. Johannessen
Keyword(s):  
Thin Film ◽  
Phase Formation ◽  
Al Thin Film ◽  
And Diffusion ◽  
Deposition Conditions

Clean Electron Microscope Substrate Films Used for Micrometeorite Collection and Study

1967 ◽  
Vol 25 ◽  
pp. 366-367
Author(s):  
D. M. Davies ◽  
R. Kemner ◽  
E. F. Fullam
Keyword(s):  
Thin Film ◽  
Electron Microscope ◽  
High Altitude ◽  
Amyl Acetate ◽  
Temperature Variations ◽  
Film Forming ◽  
Film Specimen ◽  
Particulate Contaminants

All serious electron microscopists at one time or another have been concerned with the cleanliness and freedom from artifacts of thin film specimen support substrates. This is particularly important where there are relatively few particles of a sample to be found for study, as in the case of micrometeorite collections. For the deposition of such celestial garbage through the use of balloons, rockets, and aircraft, the thin film substrates must have not only all the attributes necessary for use in the electron microscope, but also be able to withstand rather wide temperature variations at high altitude, vibration and shock inherent in the collection vehicle's operation and occasionally an unscheduled violent landing.Nitrocellulose has been selected as a film forming material that meets these requirements yet lends itself to a relatively simple clean-up procedure to remove particulate contaminants. A 1% nitrocellulose solution is prepared by dissolving “Parlodion” in redistilled amyl acetate from which all moisture has been removed.

Electron Microscope Observations of Magnetic and Electric Effects

1970 ◽  
Vol 28 ◽  
pp. 430-431
Author(s):  
John Silcox
Keyword(s):  
Electron Microscope ◽  
Electric Fields ◽  
Magnetic Image ◽  
Magnetic Effects ◽  
Ferromagnetic Films ◽  
Diffraction Contrast ◽  
Microscope Images ◽  
Electric Effects ◽  
Image Detail

Several aspects of magnetic and electric effects in electron microscope images are of interest and will be discussed here. Clearly electrons are deflected by magnetic and electric fields and can give rise to image detail. We will review situations in ferromagnetic films in which magnetic image effects are the predominant ones, others in which the magnetic effects give rise to rather subtle changes in diffraction contrast, cases of contrast at specimen edges due to leakage fields in both ferromagnets and superconductors and some effects due to electric fields in insulators.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Comparison of Techniques for EELS Mapping in Biology

1996 ◽  
Vol 54 ◽  
pp. 300-301
Author(s):  
R.D. Leapman ◽  
S.B. Andrews
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Image Data ◽  
Beam Current ◽  
Quantitative Information ◽  
Acquisition Time ◽  
Uniform Thickness ◽  
Electron Dose ◽  
Array Detectors ◽  
Transmission Electron

Elemental mapping of biological specimens by electron energy loss spectroscopy (EELS) can be carried out both in the scanning transmission electron microscope (STEM), and in the energy-filtering transmission electron microscope (EFTEM). Choosing between these two approaches is complicated by the variety of specimens that are encountered (e.g., cells or macromolecules; cryosections, plastic sections or thin films) and by the range of elemental concentrations that occur (from a few percent down to a few parts per million). Our aim here is to consider the strengths of each technique for determining elemental distributions in these different types of specimen.On one hand, it is desirable to collect a parallel EELS spectrum at each point in the specimen using the ‘spectrum-imaging’ technique in the STEM. This minimizes the electron dose and retains as much quantitative information as possible about the inelastic scattering processes in the specimen. On the other hand, collection times in the STEM are often limited by the detector read-out and by available probe current. For example, a 256 x 256 pixel image in the STEM takes at least 30 minutes to acquire with read-out time of 25 ms. The EFTEM is able to collect parallel image data using slow-scan CCD array detectors from as many as 1024 x 1024 pixels with integration times of a few seconds. Furthermore, the EFTEM has an available beam current in the µA range compared with just a few nA in the STEM. Indeed, for some applications this can result in a factor of ~100 shorter acquisition time for the EFTEM relative to the STEM. However, the EFTEM provides much less spectral information, so that the technique of choice ultimately depends on requirements for processing the spectrum at each pixel (viz., isolated edges vs. overlapping edges, uniform thickness vs. non-uniform thickness, molar vs. millimolar concentrations).

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