Direct Evidence of Surface Roughness in Small Metallic Particles

1994 ◽  
Vol 368 ◽  
Author(s):  
Miguel Jose Yacaman ◽  
Samuel Tehuacanero ◽  
Cristina Zorrilla ◽  
Gabriela Diaz
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Surface Roughness ◽  
Direct Evidence ◽  
High Resolution Electron Microscopy ◽  
Detailed Structure ◽  
Metallic Particles ◽  
New Information ◽  
Resolution Electron

ABSTRACTThe characterization of nanoparticles is of prime importance in catalysis. High Resolution Electron Microscopy coupled with image processing has produce a lot of new information on the detailed structure of the particles. In this paper we discuss the possibility of applying these techniques to the study of surface roughness.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

Interface structures in polycrystalline ceramic materials

1986 ◽  
Vol 44 ◽  
pp. 468-471
Author(s):  
K. J. Morrissey
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Physical And Mechanical Properties ◽  
High Resolution Electron Microscopy ◽  
Ceramic Materials ◽  
Polycrystalline Materials ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Interface Structures

Grain boundaries and interfaces play an important role in determining both physical and mechanical properties of polycrystalline materials. To understand how the structure of interfaces can be controlled to optimize properties, it is necessary to understand and be able to predict their crystal chemistry. Transmission electron microscopy (TEM), analytical electron microscopy (AEM,), and high resolution electron microscopy (HREM) are essential tools for the characterization of the different types of interfaces which exist in ceramic systems. The purpose of this paper is to illustrate some specific areas in which understanding interface structure is important. Interfaces in sintered bodies, materials produced through phase transformation and electronic packaging are discussed.

High-resolution electron microscopy of nanostructured materials

1995 ◽  
Vol 53 ◽  
pp. 172-173
Author(s):  
M. José-Yacamán
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Nanostructured Materials ◽  
High Resolution Electron Microscopy ◽  
Hrem Image ◽  
Small Particles ◽  
Resolution Electron ◽  
Nanophase Materials

Electron microscopy is a fundamental tool in materials characterization. In the case of nanostructured materials we are looking for features with a size in the nanometer range. Therefore often the conventional TEM techniques are not enough for characterization of nanophases. High Resolution Electron Microscopy (HREM), is a key technique in order to characterize those materials with a resolution of ~ 1.7A. High resolution studies of metallic nanostructured materials has been also reported in the literature. It is concluded that boundaries in nanophase materials are similar in structure to the regular grain boundaries. That work therefore did not confirm the early hipothesis on the field that grain boundaries in nanostructured materials have a special behavior. We will show in this paper that by a combination of HREM image processing, and image calculations, it is possible to prove that small particles and coalesced grains have a significant surface roughness, as well as large internal strain.

HRTEM simulation of interfacial structure in amorphous multilayers

1989 ◽  
Vol 47 ◽  
pp. 466-467
Author(s):  
Margaret L. Sattler ◽  
Michael A. O'Keefe
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Cross Section ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Multilayer Sample ◽  
Resolution Electron ◽  
Multilayered Materials ◽  
Simulated Images

Multilayered materials have been fabricated with such high perfection that individual layers having two atoms deep are possible. Characterization of the interfaces between these multilayers is achieved by high resolution electron microscopy and Figure 1a shows the cross-section of one type of multilayer. The production of such an image with atomically smooth interfaces depends upon certain factors which are not always reliable. For example, diffusion at the interface may produce complex interlayers which are important to the properties of the multilayers but which are difficult to observe. Similarly, anomalous conditions of imaging or of fabrication may occur which produce images having similar traits as the diffusion case above, e.g., imaging on a tilted/bent multilayer sample (Figure 1b) or deposition upon an unaligned substrate (Figure 1c). It is the purpose of this study to simulate the image of the perfect multilayer interface and to compare with simulated images having these anomalies.

Digital image processing for high resolution electron microscopy

1988 ◽  
Vol 107 (2) ◽  
pp. 521-530 ◽  
Author(s):  
W. Coene ◽  
A. F. de Jong ◽  
D. van Dyck ◽  
G. van Tendeloo ◽  
J. van Landuyt
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
High Resolution ◽  
Digital Image Processing ◽  
Digital Image ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron

Metallic Particles Supported in Several Synthetic Zeolitic Materials

1990 ◽  
Vol 183 ◽  
Author(s):  
Dwight R. Acosta ◽  
Miguel J. Yacaman
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Metallic Particles ◽  
Resolution Electron ◽  
Zeolitic Materials

AbstractHigh resolution electron microscopy observations were carried out in several zeolitic systems with different supported metallic phases in order to determine besides distributions of metallic particles, possible preferential orientations of metallic phases during impregnation processes and to detect some crystallographic relations between metallic particles and support.

Microstructural Studies of the WO3/TiO2 Monolayer Catalyst System Using High Resolution Electron Microscopy

1994 ◽  
Vol 344 ◽  
Author(s):  
A. Burrows ◽  
C. J. Kiely ◽  
R. W. Joyner ◽  
H. Knözinger ◽  
F. Lange
Keyword(s):  
Electron Microscopy ◽  
Surface Roughness ◽  
High Resolution ◽  
Structural Models ◽  
High Resolution Electron Microscopy ◽  
Catalyst System ◽  
Mechanical Mixing ◽  
Chemical Methods ◽  
Resolution Electron ◽  
Microstructural Studies

AbstractWe have characterised the WO3T'iO2 (anatase) catalyst system using High Resolution Electron Microscopy. We will show that the overlayer preserves the surface roughness of titania and consists of 2D-hexagonal clusters that have a definite orientation relationship with the support. The contrast observed from these clusters is discussed in terms of existing structural models. A comparison between traditional chemical methods of preparation and simple mechanical mixing is made to assess the effectiveness of the latter to disperse WO3.

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