Conducting nanowires in insulating ceramics.

Low-dimensional structures, such as microclusters, quantum dots and one- or two-dimensional (1D or 2D) quantum wires, are of scientific and technological interest due to their unusual physical properties, which are quite different from those in the bulk. Here we present a successful method for fabricating conducting nanowire bundles inside an insulating ceramic single crystal by using unidirectional dislocations. A high density of dislocations (10(9) cm(-2)) was introduced by activating a primary slip system in sapphire (alpha-Al2O3 single crystal) using a two-stage deformation technique. Plate specimens cut out from the deformed sapphire were then annealed to straighten the dislocations. Finally, the plates on which metallic Ti was evaporated were heat-treated to diffuse Ti atoms inside sapphire. As a result of this process, Ti atoms segregated along the unidirectional dislocations within about 5 nm diameter, forming unidirectional Ti-enriched nanowires, which exhibit excellent electrical conductivity. This simple technique could potentially to be applied to any crystal, and may give special properties to commonly used materials.

Damage and restoration of the electric power facilities in the 1995 Hyogo - Ken Nanbu earthquake

The greater Kobe region was struck by a devastating earthquake on January 17th, 1995. The Hyogo-ken Nanbu earthquake took the lives of over 5,500 people. The facilities operated by the Kansai Electric Power Company also suffered major damage from the tragic earthquake. Making use of the lessons they have learned from their long experience in responding to the extreme forces of nature, peoples of the utility were able to restore electricity to the disaster areas relatively quickly. This report summarizes the damage and restoration of the electric power facilities and some research works triggered by the earthquake.(AU)

Response caracteristics of thick sedimentary layers based on the deep vertical array observation

This paper describes the results of deep vertical array observation perfomed to understand responses of thick sedimentary horizontal layers. Acceleration responses are evaluated at 9 different levels from the bottom of the boring hole (about-500m) to the ground surface. Moderate nonlinear responses of the near surface layer are observed with the maximum surface acceleration of about 0.1G. Giving the deepest record, numerical simulations are carried out to validate a one-dimensional wave propagation analysis. Moreover, a comparison between an equivalent linear analysis and an effective stress analysis is made to observe the difference due to modelling of soil nonlinearity.(AU)