The structure of hydroxyapatite (HA) nanopowder has been determined by theta-scan precession electron diffraction (TS-PED) and Rietveld analysis. To evaluate the usefulness of the TS-PED technique, this result was compared with that of the Rietveld analysis using conventional electron diffraction (ED) and normal precession electron diffraction (PED). The intensity ratios of the (002) to (121) reflections (I002/I121) obtained by both PED data were in better agreement with the reference X-ray diffraction (XRD) data than that obtained by the conventional ED data. Although the lattice parameters of HA determined by the TS-PED data were slightly deviated from the reference XRD data, the a/c-axis ratio had the best agreement with the reference XRD data. The reliability factors (Rp, Rwp and 2) of TS-PED refinement results were substantially improved, when compared with the values obtained by the conventional ED data. These results demonstrate that TS-PED technique could be a useful analytical method for structure determination of nanopowder.
Song, Kyung; Kim, Youn-Joong; Kim, Yong-Il; Kim, Jin-Gyu
The aim of the study was to investigate age-related changes in electrogustometry (EGM) thresholds, in morphology and density of the fungiform papillae (fPap) and in vessels’ shape and density at the tip of the human tongue.In 156 nonsmokers (74 males, 82 females; age range: 10–80 years), d ... more
AbstractPrevious studies indicate that the most common result of mixing two odors is the decreased olfactory perception of one or both components in the mixture. An excellent example of this phenomenon is provided by the masking of an unpleasant odor by a pleasant odor. This study hypothes ... more
Electro-olfactogram (EOG) represents the sum of generator potentials of olfactory receptor neurons in response to an olfactory stimulus. Although this measurement technique has been used extensively in animal research, its use in human olfaction research has been relatively limited. To un ... more