Publications by authors named "Katsuaki Nakazawa"

A simple method that improves the resolution of the phase measurement of differential phase-contrast (DPC) scanning transmission electron microscopy for closed-type environmental cell applications was developed and tested using a model sample simulating environmental cell observations. Because the top and bottom membranes of an environmental cell are typically far apart, the images from these membranes are shifted widely by tilt-series acquisition, and averaging the images after alignment can effectively eliminate undesired signals from the membranes while improving the signal from the object of interest. It was demonstrated that a phase precision of 2π/100 rad is well achievable using the proposed method for the sample in an environmental cell.

View Article and Find Full Text PDF

Diffraction patterns contain useful information about the materials. Recent developments in four-dimensional scanning transmission electron microscopy and the acquisition of the spatial distribution of diffraction patterns have produced significant results. The acquisition of a temporal series of diffractions is achieved for a stationary beam.

View Article and Find Full Text PDF
Article Synopsis
  • Direct observation of copper (Cu) within Cu-chabazite (CHA) zeolite has been successfully achieved through a method called electron ptychography, using Wigner distribution deconvolution for analysis.
  • The study assessed the imaging capabilities of the ptychography technique by comparing simulated images of zeolite columns with and without Cu, revealing that false contrasts can occur but the method can effectively differentiate between Cu-containing and Cu-free columns.
  • Experimental results indicated that images taken of samples containing Cu displayed significant contrast in the six-membered rings, whereas no such contrast was seen in those without Cu, highlighting ptychography's potential for studying sensitive materials at the atomic level.
View Article and Find Full Text PDF