Life Sciences Commons^™

Progress In Element Analysis On A High-Voltage Electron Microscope, W. F. Tivol, D. Barnard, T. Guha

Scanning Electron Microscopy

X-Ray microprobe (XMA) and electron energy-loss (EELS) spectrometers have been installed on the high-voltage electron microscope (HVEM). The probe size has been measured and background reduction is in progress for XMA and EELS as are improvements in electron optics for EELS and sensitivity measurements.

XMA is currently useful for qualitative analysis and has been used by several investigators from our laboratory and outside laboratories. However, EELS background levels are still too high for meaningful results to be obtained. Standards suitable for biological specimens are being measured, and a library for quantitative analysis is being compiled.

Mineral Migration In The Wheat Kernel During Mill Conditioning, A. Al Saleh, B. Bouchet, D. J. Gallant

Food Structure

The structure and histology of the kernel govern migration of water during conditioning or drying. Studies by the energy dispersive x-ray system under the SEM have shown that during an increase of water content from 11.5 to 16.5 per cent, soluble elements migrated from the peripheral bran, accumulated in the aleurone cells and passed through its walls to the endosperm of the kernel if the water content was above 14.5 per cent. Results of study were compared with analyses of milling fractions obtained under the same conditions.

Energy Selecting Electron Microscopy, F. P. Ottensmeyer

Scanning Electron Microscopy

One of the major improvements in transmission electron microscopy over the last years is the addition of the capability of producing images with electrons that have specific narrow energy bands out of the total spectrum of energies they possess after having passed through the specimen. Though the idea is not new, the power of this application is only beginning to be recognized. Most simply, selection of elastically scattered electrons permits increased contrast in high resolution i mages in bright field, dark field, and diffraction. The use of combined elastic and inelastic signals adds entirely new contrast mechanisms, partially independent of …