Nakahara_et_al_PCCP_(2011).pdf (2.18 MB)
Defocus image contrast in hexagonally-ordered mesoporous material
journal contribution
posted on 2022-12-02, 14:56 authored by Shohei Nakahara, DAVID TANNERDAVID TANNER, D.A Hudson, S Magner, E Redington, Benjamin K. HodnettA transmission electron microscope was used to characterize a powder form of hexagonally-ordered mesoporous silica material. The structural symmetry built into this amorphous material allowed one to obtain three characteristic images, i.e. a hexagonal honey-comb structure and wide/narrow parallel lines. These images were found to originate primarily from phase contrast, which changed sensitively with defocusing. To further understand the contrast behaviour of these images, an analytical form of the defocus contrast theory was developed and applied to the simulation of the characteristic wide/narrow parallel line images. The simulation was found to be in good qualitative agreement with experiments, where changes in focus conditions and specimen thickness were predicted to alter the contrast in the resulting parallel-line type images.
History
Publication
Royal Chemistry Chemical Physics;Jan, 21, 13(3), pp. 1189-1200Publisher
Royal Society of ChemistryNote
peer-reviewedLanguage
EnglishAlso affiliated with
- Bernal Institute
Department or School
- Physics
- Chemical Sciences