No abstract

We propose a subwavelength imaging system without a lens or a mirror but with an array of metallic nanorods. The near-field components of dipole sources were plasmonically transferred through the rod array to reproduce the source distribution in the other side. We calculated the field distribution at the different planes of imaging process using the finite-difference time-domain algorithm and found that the spatial resolution was 40 nm given by the rod size and spacing. A typical configuration is a hexagonal arrangement of silver rods of 50 nm height and 20 nm diameter. We also show that the image formation highly depends on the coherence and the polarization of the source distribution and the source-array distance.

A series of structural polytypes formed in an Mg-1at.%Zn-2at.%Y alloy has been identified, which are reasonably viewed as long-period stacking derivatives of the hcp Mg structure with alternate AB stacking of the close-packed atomic layers. Atomic-resolution Z-contrast imaging clearly revealed that the structures are long-period chemical-ordered as well as stacking-ordered; unique chemical order along the stacking direction occurs as being synchronized with a local faulted stacking of AB'C'A, where B' and C' layers are commonly enriched by Zn/Y atoms.

The National Metrology Institute of Japan (NMIJ) has improved the laser flash technique to reduce uncertainty in thermal diffusivity measurements of solid materials above room temperature. An advanced laser flash apparatus was constructed after the following technical improvements had been made. (i) Uniform pulse heating of a specimen was achieved with an improved laser beam using an optical fibre (decreasing the error due to nonuniform heating). (ii) A fast infrared radiation thermometer with an absolute temperature scale was developed (decreasing the error due to nonlinear temperature detection). (iii) A new data analysis algorithm employing curve-fitting method whereby the entire region of the temperature history curve is fitted by the theoretical solution under the real boundary condition was introduced (decreasing the heat loss error). The precision and accuracy of the apparatus were demonstrated by measuring specimens of glassy carbon which is a candidate reference material for a thermal diffusivity standard to be supplied by the NMIJ.