W H Hardy | PubMed Health

PubMed2002

Evidence for static magnetism in the vortex cores of ortho-II YBa2Cu3O6.50.

Evidence for static alternating magnetic fields in the vortex cores of underdoped YBa2Cu3O6+x is reported. Muon spin rotation measurements of the internal magnetic field distribution of the vortex state of YBa2Cu3O6.50 in applied fields of H = 1 T and H = 4 T reveal a feature in the high-field tail of the field distribution which is not present in optimally doped YBa2Cu3O6.95 and which fits well to a model with static magnetic fields in the vortex cores. The magnitude of the fields is estimated to be 18(2) G and decreases above T = 10 K. We discuss possible origins of the additional vortex core magnetism within the context of existing theories.

Journal Article↗

PubMed1982

Digital image processing: a path to better pictures.

Digital image processing can be used to provide enhanced performance in scanning electron column instruments. Improved visualization, reduced specimen damage, and quantization can be achieved. The system described here provides hardware for digitization and storage of multiple images simultaneously, and multimode scan generation. System software provides easy scan control, image digitization, automatic prescale adjust on acquisition, grey scale histogram generation, grey scale compression or expansion, image filtering, smoothing, and random color assignment to grey levels. Image digitization and processing was done using the EG&G ORTEC Image Master Microanalyzer in conjunction with a JEOL 100CX TEMSCAN and a JEOL JSM 35. Examples of image processing of bright and dark field STEM images of biological specimens are shown. An example of X-ray image processing using a two-dimensional filter function to reduce image noise is also shown.

Computers↗