Biomedical subjects

Shunsuke Muto

Publications and source records attributed to Shunsuke Muto.

5 recordsLinked to original sources

PubMed2006

Spectral restoration and energy resolution improvement of electron energy-loss spectra by Pixon reconstruction: II. Application to practical ELNES analysis of low SNR.

We applied Pixon deconvolution as introduced in Part I to several practical, examples of low signal-to-noise ratio (SNR), electron energy-loss spectra with a goal toward restoring their fine spectral features and/or improving the energy resolution. We demonstrate that by directly fitting the two-dimensional spectral data recorded on the CCD; the method enables us to reveal fine spectral structures. Consequently, Pixon reconstruction extends the ability to probe electronic states in very spatially localized areas, a capability currently unique to our method.

Algorithms↗

PubMed2006

Spectral restoration and energy resolution improvement of electron energy-loss spectra by Pixon reconstruction: I. Principle and test examples.

We explore the use of the Pixon method, one of the highest performance image reconstruction methods available today, for the analysis of electron energy loss spectra (EELS). The method takes particular advantage of two-dimensional (2-D) CCD data, in which the data are blurred by a PRF (point-response-function as measured by the low-loss spectrum) both in the direction of energy dispersion and in the cross-dispersion direction. The Pixon method is used to simultaneously (i) deconvolve the PRF, increasing the spectral resolution, and (ii) fit the data in the cross-dispersion direction which efficiently combines the signal into a single parent spectrum. Relative to 1-D methods, we demonstrate that our 2-D treatment (i) more effectively detects weak features and (ii) allows EELS methods to be applied to much lower signal-to-noise ratio data. Both of these advantages are critical to the future development of EELS analysis.

Algorithms↗

PubMed2006

Site-specific electronic structure analysis by channeling EELS and first-principles calculations.

Site-specific electronic structures were investigated by electron energy loss spectroscopy (EELS) under electron channeling conditions. The Al-K and Mn-L(2,3) electron energy loss near-edge structure (ELNES) of, respectively, NiAl2O4 and Mn3O4 were measured. Deconvolution of the raw spectra with the instrumental resolution function restored the blunt and hidden fine features, which allowed us to interpret the experimental spectral features by comparing with theoretical spectra obtained by first-principles calculations. The present method successfully revealed the electronic structures specific to the differently coordinated cationic sites.

Journal Article↗

PubMed2003

Reverse Monte Carlo analysis of extended energy-loss fine structure for disordered structures of tetrahedrally coordinated materials: its applicability.

Capabilities of the reverse Monte Carlo method for characterizing the short-range structural correlations of solids were examined in the analysis of extended energy-loss fine structure (EXELFS). Since this method gives a three-dimensional atomic configuration consistent with the experimental EXELFS spectra, one can extract the statistical distributions of bond lengths, coordination numbers and bond angles of atom species of interest, which have been hard to achieve by conventional EXELFS analysis. The method was applied for the determination of amorphous Si structures and the damaged structure of an electron-irradiated SiC crystal. Advantages and disadvantages of the present method over the precise diffraction intensity measurement are discussed.

Carbon↗

PubMed2002

Development of new TEM specimen holder for cathodoluminescence detection.

A simple, new TEM specimen holder to detect cathodoluminescence (CL) in a transmission electron microscope has been developed. This holder accommodates a flat light-collecting reflector below the specimen and CL signals are guided to an optical spectrometer outside of the microscope through a quartz optical fibre. The compact system requires no modification of the microscope itself and allows large-angle specimen tilting and easy combination with other associate analytical tools. Test data are presented to aid the future application of the holder.

Journal Article↗