Numerical analysis of scattering fields by a multiple plane grating using shadow theory.

In the shadow theory, a new description of electromagnetic fields using scattering factors has been employed. This paper presents a new numerical method based on scattering factors for the scattering problem of a composite dielectric grating embedded with conducting strips. The scattering factors for the primary fields, which are based on the assumption of conducting strips being removed completely and those for the secondary fields generated by the surface electric currents on conducting strips, are introduced.

Three-dimensional analysis of structural coloration by a slanted dielectric grating.

The stripe of the tropical freshwater fish "neon tetra" consists of many iridophores, in which tilted reflecting platelets are periodically arranged. The neon tetra has structural coloration and changes the color of a stripe in response to the surrounding conditions. The mechanism of the color change is thought to be controlling a slant angle of the platelets and changing the spacing between the platelets.

Reciprocity theorem and accuracy evaluation on scattering fields by dielectric gratings.

In the theory of gratings, a diffraction solution must satisfy the energy balance and the reciprocity. This paper examines the diffraction by multilayered dielectric gratings, including lossy layers of which the solutions do not satisfy the energy balance. Applying the shadow theory to the matrix eigenvalues method, the symmetry of scattering factors in the theory and that of diffraction efficiencies are shown in some formulae and then are validated numerically.

Numerical method of applying shadow theory to all regions of multilayered dielectric gratings in conical mounting.

Nakayama's shadow theory first discussed the diffraction by a perfectly conducting grating in a planar mounting. In the theory, a new formulation by use of a scattering factor was proposed. This paper focuses on the middle regions of a multilayered dielectric grating placed in conical mounting.

Imaging active topological defects in carbon nanotubes.

A single-walled carbon nanotube (SWNT) is a wrapped single graphene layer, and its plastic deformation should require active topological defects--non-hexagonal carbon rings that can migrate along the nanotube wall. Although in situ transmission electron microscopy (TEM) has been used to examine the deformation of SWNTs, these studies deal only with diameter changes and no atomistic mechanism has been elucidated experimentally. Theory predicts that some topological defects can form through the Stone-Wales transformation in SWNTs under tension at 2,000 K, and could act as a dislocation core.

Special purpose computer system for flow visualization using holography technology.

We have designed a special purpose computer system for visualizing fluid flow using digital holographic particle tracking velocimetry (DHPTV). This computer contains an Field Programmble Gate Array (FPGA) chip in which a pipeline for calculating the intensity of an object from a hologram by fast Fourier transform is installed. This system can produce 100 reconstructed images from a 1024 x 1024-grid hologram in 3.