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The contact resistance of Au/Ni/p-GaN ohmic contacts for different annealing conditions was measured. This was then correlated with microstructure, including phase distribution, observed by high-resolution electron microscopy combined with energy-filtering imaging. A contact resistance of 2.22 x 10(-4) ohms cm2 for Au/Ni contacts to p-GaN after annealing at 500 degrees C for 5 min in air ambient was obtained. NiO layers were identified at the interface and upper area of annealed Ni/Au/p-GaN for air ambient. In addition, an Au layer was found at the interface of p-GaN due to a reversal reaction during annealing. Identification of the observed phases is discussed, along with possible formation mechanisms for the ohmic contacts in the Au/Ni/p-GaN system.

Beta-SiC nanorods have been synthesized by the reaction of SiO and carbon nano-capsules. For the synthesis of SiC nanorods, it was examined that the reaction temperature and the ratio of SiO to carbon nanocapsules are important and the most appropriate temperature and ratio are around 1380 degreesC and 5:2, respectively. The synthesized SiC nanorods were characterized by high-resolution electron microscopy. Most of the SiC nanorods are straight and have the diameter of 30-150 nm while the SiC tips of the SiC nanorods have the size 100-400 nm. The SiC nanorods have many stacking faults normal to the [111] direction. Each SiC nanorod has one kind of preferential axis direction, which is either parallel or normal to the [111] direction. Based on the microstructural analysis of the SiC nanorods, a possible growth mechanism of the SiC nanorods is proposed.

The direct crystal connection at the dentino-enamel junction was investigated using high resolution electron microscope. High resolution electron microscopy revealed that lattice fringes of dentine crystals entered into and directly contacted with those of enamel crystals. In such junction, intricate and irregular tilt boundaries were located in fusion levels. Dentine crystals were closely joined at the outermost dentine surface where fusions occurred. At the fusion level, dislocation appeared to form tilt boundaries. The tilt boundaries at the fusion levels in dentine crystals had more regular curvature than those at the dentino-enamel junction. These findings suggest that growth of dentine crystals brings direct connection with enamel crystals. Furthermore, it is suspected that dentino-enamel junction is weak in mechanical and/or chemical attacks.

Modulated structures in the Pb-doped Bi-Sr-Ca-Cu-O superconductiong oxides, Bi 2-x Pb x Sr 2 CaCu 2 O y (x=0∼0.8), were studied by means of high resolution electron microscopy and electron diffraction. Two types of modulated structure with different modulation modes and cell dimensions were found in the compound. The Pb content was closely related to the structure types and the periods of modulation