Direct profile imaging

This technique of direct profile imaging is powerful for the determination of the 3D shape of very small particles (2-8 nm) and the structural characterization of the interface at the atomic level, as for example the Pd/MgO and Pd/ZnO interfaces. ... 

Figure 3. TEM surface profile images of MCM-41 specimens overheated at 165 °C for (a) 96 h and (b) 48 h. The view directions are along (a) the [100] direction and (b) the pore axis.

The knowledge of the structure and the morphology of the metal clusters is necessary if we want to understand the reaction kinetics at the atomic level. The more versatile technique to study the structure and the morphology of supported metal cluster is TEM. It can provide directly the structure and the epitaxial relationships on a collection of clusters in the diffraction mode. By High Resolution TEM it is possible to get this information at the level of one cluster [83]. By using high-resolution profile imaging it is possible to measure the lattice distortion at the interface [84], These capabilities are very unique for TEM. Such structural information can be obtained in situ by diffraction techniques but only on a collection of clusters [14, 29]. To illustrate the structural characterization by TEM we present the case of Pd clusters on MgO(l 0 0), which will be discussed in the next sections. 

Chaueand, P., Capeioli, R. M. (2002). Direct profiling and imaging of peptides and proteins from mammalian cells and tissue sections by mass spectrometry. Electrophoresis 23, 3125-3135. 

When HRTEM is used for examining nanoparticles of oxides, in which the proportion of surface area greatly increases, most structural information concerns the surface. For example, HRTEM images of core-shell quantum dots can show the shell structure and its thickness directly. HRTEM images of metal oxide nanotubes can also be regarded as surface profile images. The appHcation of TEM in nanomaterials will be further discussed below. 

Zhang, H., Cha, S., Yeung, E.S., (2007) Colloidal graphite-assisted laser desorption/ionization MS and MS(n) of small molecules. 2. Direct profiling and MS imaging of small metabolites from fruits. Analytical Chemistry, 79, 6575-6584. 

Caprioli, R.M., Farmer, T.B. and GUe, J., Molecular imaging of biological samples localization of peptides and proteins using MALDI-TOF MS. Anal. Chem., 69, 4751-4760 (1997). Chaurand, P., Stoeckh, M. and Caprioli, R.M., Direct profiling of proteins in biological tissue sections by MALDI mass spectrometry. Anal. Chem., 71, 5263-5270 (1999). 

Some discontinuities may be identified by a conventional two-dimensional ultrasonic technique, from which the well-known C-scan image is the most popular. The C-scan technique is relatively easy to implement and the results from several NDE studies have been very encouraging [1]. In the case of cylindrical specimens, a circular C-scan image is convenient to show discontinuity information. The circular C-scan image shows the peak amplitude of a back-scattered pulse received in the circular array. The axial scan direction is shown as a function of transducer position in the circular array. The circular C-scan image serves also as an initial step for choosing circular B-scan profiles. The latter provides a mapping between distance to the discontinuity and transducer position in the circular array. 

The magnetization profile in the y-direction is recovered by Fourier transfonnation with respect to G. B1.14.2.4 2D SPIN-ECHO FT IMAGING AND K-SPACE... 

Today dynamic SIMS is a standard technique for measurement of trace elements in semiconductors, high performance materials, coatings, and minerals. The main advantages of the method are excellent sensitivity (detection limit below 1 pmol mol ) for all elements, the isotopic sensitivity, the inherent possibility of measuring depth profiles, and the capability of fast direct imaging and 3D species distribution. 

In Fig. 4 we show an atomic resolution image of a carbon tube. The structure imaged at the upper right corner of the picture comes from another tube. Both of them were —1000 A long. A perfect honeycomb surface structure is observed. By taking into account the curvature of the tube surface and the STM imaging profile, we find the same lattice parameter as that of. graphite (1.42 A). This directly proves that the tubu-... 

---