Comparative Studies of the Degradation of Several Zeolites Under Electron Irradiation

1987 ◽  
Vol 111 ◽  
Author(s):  
D. R. Acosta ◽  
O. Guzman ◽  
P. Del Angel ◽  
J. Dominguez
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Resolution ◽  
Electron Irradiation ◽  
Comparative Studies ◽  
Structural Characteristics ◽  
High Resolution Electron Microscopy ◽  
Degradation Process ◽  
Optical Parameters ◽  
Resolution Electron

High resolution electron microscopy has proven to be a powerful technique to determine structural characteristics of zeolites (l–2),symmetry variations and identification of several kind of defects.Together with ideal projected potential images, the microscopist usually finds in electron micrographs the influence of electro-optical parameters and alterations of the crystallinity of the material under electron irradiation. One of the purposes of this workis to contributetothe understanding of the degradation process of zeolites under electron irradiation in the electron microscope and in this way, discriminate when it is possible, what is reliable information recorded in the images obtained in high resolution conditions.

scholarly journals Vitrification of Y zeolite and its effects on HREM images

1986 ◽  
Vol 44 ◽  
pp. 774-775
Author(s):  
R. Csencsits
Keyword(s):  
Electron Microscopy ◽  
Computer Simulation ◽  
Electron Microscope ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Systematic Investigation ◽  
Y Zeolite ◽  
Y Zeolites ◽  
Transmission Electron ◽  
Resolution Electron

High resolution electron microscopy (HREM) is a valuable technique for studying catalytic zeolite systems because it gives direct information about the structure and defects present in the structure. The difficulty with doing an HREM study on zeolites is that they become amorphous under electron irradiation. This work is a systematic investigation of the damage of Y zeolites in the transmission electron microscope (TEM); the goals of this study are to determine the mechanism for electron damage and to access the effects of damage in Y zeolites on their HREM images using computer simulation.

A HREM study of V/Al2O3 interface

1992 ◽  
Vol 50 (1) ◽  
pp. 146-147
Author(s):  
Y. Ikuhara ◽  
P. Pirouz ◽  
A. H. Heuer ◽  
S. Yadavalli ◽  
C. P. Flynn
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Resolution ◽  
Substrate Temperature ◽  
Molecular Beam ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Cross Sectional ◽  
Plan View ◽  
Resolution Electron

The interface structure between vanadium and the R-plane of sapphire (α-Al2O3) was studied by conventional and cross-sectional high resolution electron microscopy (HREM) to clarify the atomic structure of the interface.A 57 nm thick vanadium film was deposited on the (1102) (R) plane of sapphire by molecular beam epitaxy (MBE) at a substrate temperature of 920 K in a vacuum of 10-10torr. The HREM observations of the interface were done from three directions: two cross-sectional views (parallel to [0221]Al2O3 and [1120]Al2O3) and a plan view (parallel to [2201]Al2O3) by a top-entry JEOL 4000EX electron microscope (400 kV).

Application of hollow-cone illumination to High-resolution electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 692-693
Author(s):  
R.A. Herring
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Objective Lens ◽  
Hollow Cone ◽  
Lattice Image ◽  
Resolution Electron ◽  
High Resolution Images ◽  
Z Contrast

TEM hollow cone illumination can produce high resolution images having atomic number (Z) contrast within a lattice image. Inorder to produce these images, the contribution of four sources of electrons should be considered. These are the main, inelastically scattered, elastically scattered, and diffracted beams. This abstract discusses these sources of electrons to the hollow cone (HC) image, and then goes further to propose a possible method of extending the resolution of the electron microscope by using diffracted HC beams to form holograms which should remove the limitation on resolution imposed by the objective lens and inelastically scattered electrons. A Philips EM 430T was used to take the electron micrographs.

Time-resolved high-resolution electron microscopy of nanometer-scale electron beam processing of PbTe films

1996 ◽  
Vol 54 ◽  
pp. 980-981
Author(s):  
T. Kizuka ◽  
N. Tanaka
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Electron Microscope ◽  
High Resolution ◽  
Room Temperature ◽  
High Resolution Electron Microscopy ◽  
Nanometer Scale ◽  
Time Resolved ◽  
Electron Beam Processing ◽  
Resolution Electron

Various kinds of nanometer scale processings are required to produce advanced materials, for example, nano-structured electric devices. Electron beam processing at nanometer scale using STEM and TEM, such as drilling and line-writing, is recently interested as a most useful method. Details of structural change during the processing should be elucidated at atomic resolution in order to establish the processing. In the present work we have processed lead telluride (PbTe) films with nanometer electron beam in a high-resolution transmission electron microscope and in-situ observed the variation of atomic arrangements during the processing.PbTe of 99.99% was vacuum-deposited on air-cleaved (001) surfaces of sodium chloride at room temperature. Time-resolved high-resolution electron microscopy was carried out at room temperature using a 200-kV electron microscope (JEOL, JEM2010) equipped with a high sensitive TV camera and a video tape recorder. The spatial resolution of thesystem was 0.2 nm at 200 kV and the time resolution was 1/60 s. Electron beam irradiation density was 120 A/cm2 at the processing and the observation.

High Resolution Electron Microscopy studies of the degradation process of the calcium A zeolite

1986 ◽  
Vol 44 ◽  
pp. 852-853
Author(s):  
D.R. Acosta N.
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Thermal Treatment ◽  
Amorphous State ◽  
High Resolution Electron Microscopy ◽  
Degradation Process ◽  
Auger Spectroscopy ◽  
Nitrogen Atmosphere ◽  
Vacuum Line ◽  
Resolution Electron

The change from the crystalline to the amorphous state of the sodium A zeolite, has been investigated by Bursill and by Thomas. From individual HREM pictures those authors suggest three different mechanisms responsible for the degradation process. In the present work the degradation of the calcium A zeolite, characterized also by Auger spectroscopy, was studied by HREM methods. The sample was under thermal treatment at 450°C during four hours in a vacuum line after which it was mounted in the microscope in a nitrogen atmosphere.

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