Finite-element solution of Rayleigh-wave scattering from reflective gratings on a piezoelectric substrate

A numerical approach that combines the finite-element method (FEM) and the analytical method is discussed. To treat a large periodic structure in which a repetition of complicated components arises, the substructure method is introduced. As a result, the mutual interaction between surface waves and bulk waves is automatically taken into account over the entire discontinuity region. In addition, the FEM with Hermitian line elements is introduced to compute the propagation constants and field distributions of propagating modes in uniform piezoelectric waveguides that are needed for constructing analytical solutions. To show the validity and usefulness of this approach, examples for various metallic gratings on 128 degrees Y-X LiNbO(3) substrate are computed. The computed results are in approximate agreement with the earlier experimental results.     

Development of a large-capacity static var generator using self-cornmutated inverters for improving power transmission system stability

A Static Var Generator (SVG) based on a self-commutated inverter using GTO thyristors has been newly developed. The size of the SVG used for improving power system stability will be as large as approximately 100 MVA. The technical subjects to be solved for developing such a large SVG are summarized as follows:

• compact design;
• harmonic elimination by means of multiple transformers; and
• large inverter with series connection of GTO thyristors.

This paper describes the solutions to these subjects, especially the application of a large number of multipulse connection and series connection of GTO thyristors, including the analysis of the basic performance of SVG and the multiple transformer. The test results of a 12-pulse partial model (8 MVA) and a 48-pulse miniaturized model prove the solutions proposed in this paper to be effective and reasonable.     

Analysis of vibration and shock occurring in transport systems

The agreement between the practical data and theoretical values has been examined for almost all of the formulae used to determine the optimum function that can express the relationship between the shock-acceleration or vibration-acceleration and their number of occurrences. These formulae, however, are not always suitable for all analyses. In order to find the optimum formula for each condition, the following points have been considered:

• i agreement between the calculated value and measured data
• ii difficulty in the calculation procedure
• iii difficulty in comparison of the data obtained
• iv possibility of extrapolation.

The following results were obtained:

• i In general, hybrid function, irrational function and Weibull distribution can be used to express the relationship.
• ii For comparison of experimental data obtained in different transport conditions, irrational function and Weibull distribution have fewer parameters than other functions.
• iii In the case of the package test condition where an extrapolation is required, the hybrid function and irrational function are the most suitable.

     

Mobile Silk Fibroin Electrode for Manipulation and Electrical Stimulation of Adherent Cells

Microfabricated mobile electrodes, nanopallets, designed to provide adherent cells with electrical stimulation are reported. Nanopallets composed of a cross‐linked silk fibroin hydrogel matrix incorporated with poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) are used. The silk fibroin composite is characterized not only by mechanical and electrical conductive properties, but also by its optical transparency in both the visible and ultraviolet regions, and by its biocompatibility with adherent cells. It is demonstrated that the adherent cells, including normal cell‐lined cells and primary neuronal cells, loaded on the nanopallets can be manipulated while faithfully retaining their adhesive properties. By applying voltages via the nanopallets, the voltage‐dependent calcium channels expressed in the cells are selectively stimulated, and this is confirmed by using confocal fluorescent microscopy during manipulation and performing multiangle observations. These features are attributed to both the mobile operation of the transparent nanopallets, and the ability to simultaneously measure electrical signals and perform fluorescent observations.     

Luminescence properties of Pr<Subscript>6</Subscript>O<Subscript>11</Subscript>-doped and PrF<Subscript>3</Subscript>-doped germanate glasses for wideband NIR phosphor

We have synthesized 0.12Pr₆O₁₁–45Sb₂O₃–10ZnO–45GeO₂ glass and 0.72PrF₃–45Sb₂O₃–10ZnO–45GeO₂ as a wideband near-infrared phosphor for LED-based light-sources. We have achieved an ultra-wideband luminescence from 700 to 1100 nm from both samples. Luminescence intensity around 730 nm (³P₀ → ³F₄ transition) was lower than that around 1040 nm (¹D₂ → ³F₄ transition) in the Pr₆O₁₁-doped sample. On the other hand, luminescence intensity around 730 nm was higher than that around 1040 nm in PrF₃-doped sample. These results indicated that a phonon energy around Pr³⁺ ions should be decreased by substituting PrF₃ for Pr₆O₁₁. An output power of the PrF₃-doped sample was 1.5 times higher than that of the Pr₆O₁₁-doped sample. A measured fluorescence lifetime of ¹D₂ level in the PrF₃-doped sample was shorter than that in the Pr₆O₁₁-doped one. These results indicated that oxide glasses doped with rare-earth fluoride should be useful for our practical wideband NIR phosphor.     

Synthesis of a stroboscopic image from a hand-held camera sequence for a sports analysis

Computational Visual Media - This paper presents a method for synthesizing a stroboscopic image of a moving sports player from a hand-held camera sequence. This method has three steps: synthesis of...