Nondestructive determination of composition depth profiles on subnanometer scales using angle resolved Auger spectroscopy

1992 ◽  
Vol 10 (4) ◽  
pp. 2826-2831 ◽  
Author(s):  
G. N. Derry ◽  
W. E. Vanderlinde
Author(s):  
John Silcox

Determination of the microstructure and microchemistry of small features often provides the insight needed for the understanding of processes in real materials. In many cases, it is not adequate to use microscopy alone. Microdiffraction and microspectroscopic information such as EELS, X-ray microprobe analysis and Auger spectroscopy can all contribute vital parts of the picture. For a number of reasons, dedicated STEM offers considerable promise as a quantitative instrument. In this paper, we review progress towards effective quantitative use of STEM with illustrations drawn from studies of high Tc superconductors, compound semiconductors and metallization of H-terminated silicon.Intrinsically, STEM is a quantitative instrument. Images are acquired directly by detectors in serial mode which is particularly convenient for digital image acquisition, control and display. The VG HB501A at Cornell has been installed in a particularly stable electromagnetic, vibration and acoustic environment. Care has been paid to achieving UHV conditions (i.e., 10-10 Torr). Finally, it has been interfaced with a VAX 3200 work station by Kirkland. This permits, for example, the acquisition of bright field (or energy loss) images and dark field images simultaneously as quantitative arrays in perfect registration.


2020 ◽  
Vol 11 (1) ◽  
pp. 101
Author(s):  
Carlo Boursier Niutta

A new approach for the nondestructive determination of the elastic properties of composite laminates is presented. The approach represents an improvement of a recently published experimental methodology based on the Impulse Excitation Technique, which allows nondestructively assessing local elastic properties of composite laminates by isolating a region of interest through a proper clamping system. Different measures of the first resonant frequency are obtained by rotating the clamping system with respect to the material orientation. Here, in order to increase the robustness of the inverse problem, which determines the elastic properties from the measured resonant frequencies, information related to the modal shape is retained by considering the effect of an additional concentrated mass on the first resonant frequency. According to the modal shape and the position of the mass, different values of the first resonant frequency are obtained. Here, two positions of the additional mass, i.e., two values of the resonant frequency in addition to the unloaded frequency value, are considered for each material orientation. A Rayleigh–Ritz formulation based on higher order theory is adopted to compute the first resonant frequency of the clamped plate with concentrated mass. The elastic properties are finally determined through an optimization problem that minimizes the discrepancy on the frequency reference values. The proposed approach is validated on several materials taken from the literature. Finally, advantages and possible limitations are discussed.


2016 ◽  
Vol 82 (5) ◽  
pp. 743-752 ◽  
Author(s):  
KUMIKO KUBO ◽  
YOSHIHIRO MATSUMOTO ◽  
KOICHI KUWAHARA ◽  
SYUUICHI OKABE ◽  
SHIGETO TANIYAMA ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document