ABSTRACT
Time-resolved electron holography was implemented in a transmission electron microscope by means of electron beam gating with a parallel-plate electrostatic deflector. Stroboscopic observations were performed by accumulating gated electron interference images while applying a periodic modulation voltage to a specimen. Electric polarization in an ionic liquid specimen was observed under applied fields. While a static electric field in the specimen was reduced by the polarization of the material, an applied field modulated at 10 kHz was not screened. This indicates that time-resolved electron holography is capable of determining the frequency limit of dynamic response of polarization in materials. Graphical Abstract.
ABSTRACT
The magnetic microstructure in a Co-CoO obliquely evaporated tape that was subjected to a recording bit length of 250 nm was studied using electron holography. The reconstructed phase image demonstrated a periodic pattern of magnetic flux loops that were inclined to the film normal due to a well-developed columnar structure. When a magnetic field was applied to the tape for observing the remanent state by holography, the periodic pattern of the flux loops gradually disappeared. Interestingly, on applying a large magnetic field, the contour lines in the reconstructed phase image became approximately parallel to the longitudinal axis of the sliced tape, i.e. the contour lines were made to virtually deviate from the easy magnetization axis. The observations were supported by a computer simulation in which the effect of the stray magnetic field was considered.
ABSTRACT
The microstructure and magnetic domain structure of a Co-CoO obliquely evaporated tape for magnetic recording are studied by analytical electron microscopy and electron holography, respectively. While the existence of Co and CoO crystallites is confirmed by energy-filtered electron diffraction, columnar structure of the Co crystallites surrounded by the densely packed CoO crystallites is visualized by an elemental mapping method with electron energy loss spectroscopy, and the crystal orientation relation among the Co crystallites is clarified by high-resolution electron microscopy. It is found that the neighboring Co crystallites have close crystal orientations. On the other hand, electron holography reveals the magnetic flux distribution in a thin section of the tape. Although there exists the background resulting from the effect of inner potential with thickness variation, the distribution of lines of magnetic flux is found to correspond well to the recorded pattern.
Subject(s)
Cobalt/chemistry , Holography/methods , Magnetics , Oxides/chemistry , Tape Recording , Microscopy, Electron/methodsABSTRACT
An alcohol abuser with hepatitis C developed multibacterial sepsis. His mean 100% alcohol intake reached 400 ml/day. In January 2001, he suddenly experienced fever (39 degrees C) with no other symptoms. One week later, he was admitted to our hospital and was subsequently diagnosed with sepsis associated with four species of bacteria (Streptococcus constellatus, Fusobacterium mortiferum, Bacteroides thetaiotaomicron, and non-spore-forming anaerobic gram-positive bacillus). A drip infusion of imipenem/cilastatin was administrated, resulting in a successful therapeutic outcome. No underlying disorder was found except for gastric ulcers and hepatic cirrhosis. Damaged gastric mucosa was assumed to be the possible cause and route for the bacterial invasion.