Transmission resolution

The determination of the overall resolution of some measuring equipment may require more efforts, as it involves the combination of the resolution of different measuring system components. For example, the optical resolution of optical measuring systems may be calculated by the combination of the resolution of different components (e.g., their MTF - modulation transfer functions), such as lens resolution, sensor resolution, data transmission resolution, and display resolution. 

Crewe A V, Wall J and Welter L M 1968 A high resolution scanning transmission electron microscope J. Appl. Phys. 39 5861-8... 

Blodgett films direct imaging by scanning tunneling microscopy and high-resolution transmission electron... 

The spatial arrangement of atoms in two-dimensional protein arrays can be detennined using high-resolution transmission electron microscopy [20]. The measurements have to be carried out in high vacuum, but since tire metliod is used above all for investigating membrane proteins, it may be supposed tliat tire presence of tire lipid bilayer ensures tliat tire protein remains essentially in its native configuration. 

In many ways the nanocrystal characterization problem is an ideal one for transmission electron microscopy (TEM). Here, an electron beam is used to image a thin sample in transmission mode [119]. The resolution is a sensitive fimction of the beam voltage and electron optics a low-resolution microscope operating at 100 kV might... 

Figure C2.17.4. Transmission electron micrograph of a field of Zr02 (tetragonal) nanocrystals. Lower-resolution electron microscopy is useful for characterizing tire size distribution of a collection of nanocrystals. This image is an example of a typical particle field used for sizing puriDoses. Here, tire nanocrystalline zirconia has an average diameter of 3.6 nm witli a polydispersity of only 5% 1801.

Figure C2.17.6. Transmission electron micrograph and its Fourier transfonn for a TiC nanocrystal. High-resolution images of nanocrystals can be used to identify crystal stmctures. In tliis case, tire image of a nanocrystal of titanium carbide (right) was Fourier transfonned to produce tire pattern on tire left. From an analysis of tire spot geometry and spacing, one can detennine that tire nanocrystal is oriented witli its 11001 zone axis parallel to tire viewing direction [217].

Although ion transmission guides and ion traps both use the same universal physical laws to achieve control over ion behavior, the ways in which the laws are used are different, as are the objectives. The guides do not retain ions to gain control over their velocities and are used simply to transmit both slow and fast ions over a very wide range of gas pressures. Ion traps retain ions over a relatively long period of time so as to adjust their kinetic energies and thereby improve mass resolution. The so-called bath gas is used at carefully controlled pressures. 

In aes, the resolution is largely independent of the characteristics of the analy2er or source and is dictated by the natural linewidth of the Auger line (usually several eV). Therefore, in using a CMA for aes, the analyst is more concerned with transmission (and hence, sensitivity) than with resolution. In contrast to xps, the optimhation of variables is achieved for aes in the CRR mode of operation. The large transmission of the CMA relative to the CHA make it the more desirable analy2er for aes. 

The hnearity between M and makes the concept of absorbance so usehil that measurements made by sampling methods other than transmission are usually converted to a scale proportional to absorbance. The linearity between M and i is maintained only if the resolution of the spectrometer is adequate to eliminate contributions from wavelengths not absorbed by the species being measured. In addition, the apparent value of a is very dependent on resolution because a is 2l strong function of wavelength (30,31). 

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