ac magnetic instability in non-ideal type-II superconductors

The theoretical approach is carried out with the combined thermal and magnetic equations which are based on the critical state model for non-ideal type-II superconductors and include controllable physical parameters. Also, the behaviour of flux jumps is studied on Nb-Ti-Zr ternary alloy wires in the temperature region 1.8–9.0 K under various heat transfer conditions. The ac field method applied here has the advantage of determining flux jump fields more exactly than the linear sweep method.     

PWM technique for power MOSFET inverter

A sinusoidal PWM (pulsewidth-modulated) inverter suitable for use with power MOSFETs is described. The output waveforms in the proposed PWM inverter are investigated both theoretically and experimentally. A modulating signal for the three-phase PWM inverter is obtained by adding the harmonic components of integer multiples of three to the three-phase sine waves. By using the proposed modulating signal, the amplitude of the fundamental component is increased about 15% more than that of a conventional sine-wave inverter and the commutation number of the inverter is decreased to two-thirds of a conventional one     

Bow-tie-tree in EPR cables are accelerated water treeing test

The authors describe the results of an accelerated water treeing test after a period of approximately one year with two recently manufactured (1988) varieties of commercial EPR (ethylene-propylene rubber) cables, produced by different manufacturers and possessing different cable structures, as well as water impervious XLPE cable for comparison. In the test, bow-tie trees were found in the EPR insulation, which had previously been thought to develop no or few bow-tie trees. The analysis results of bow-tie in EPR cables are described     

APC-AB codec modules operating at 16 and 8 kbit/s

High-quality speech codec modules operating at 16 and 8 kb/s have been developed using an adaptive predictive coding with adaptive bit allocation (APC-AB) scheme. An optimized APC-AB algorithm is studied that reduces processing complexity while maintaining speech quality. The coding algorithm is implemented in two digital signal processors (DSPs). The DSP chips, a framing LSI circuit, a PCM codec, and some peripheral ICs are integrated in each of two compact packages, i.e. codec modules, operating at 16 or 8 kb/s. The codec module size is as small as 80 mm×50 mm×12 mm, and its typical power consumption is 500 mW using 2-μm CMOS LSI technology. At 16 kb/s this APC-AB codec achieves high speech quality, close to that of a 7-bit μ-law PCM. The codec modules are expected to be used for various applications such as customer premises multiplexers for digital leased lines, digital mobile radio, and stored-and-forward-message systems (voice-mail systems)     

Emission spectroscopy of laser ablation plasma with time gating by acousto-optic modulator

The capability of acousto-optic modulator (AOM) to perform time-gated measurements for laser ablation plasma spectroscopy has been examined. Especially, we focused on the capability of the "AOM gating" to exclude the continuum and extremely broadened spectra usually observed immediately after the laser ablation. Final goal of the use of the AOM is to achieve considerable downsizing of the system for in situ and on-site analyses. In the present paper, it is shown that narrow and clear spectral lines can be obtained with the AOM gating even if the target is submerged in water. Also, application of this technique to the targets in air is demonstrated. It has been revealed that the AOM gating is fast enough to exclude the continuum and broadened lines, while effectively acquiring sufficiently narrow atomic lines lasting slightly longer than the continuum.     

Rapid method for determining water-holding capacity in meat using video image analysis and simple formulae

To accelerate measurement of the water-holding capacity (WHC) of meat by the press method, video image analysis (VIA) and formulae were investigated. The areas of meat and meat liquid on filter paper were little affected by changes in the operating conditions of the VIA system. VIA is associated with greater repeatability, less variation due to operators and was less time consuming than planimetry. When VIA was applied to a variety of fresh meats (beef, pork, chicken and duck meat), it was possible to measure the areas of meat and liquid on filter paper under a translucent plastic plate, immediately after pressing, without drawing an outline of the meat area. VIA was also able to measure cooked meat. Drying on filter paper decreased the areas of meat and liquid slightly but hardly changed the meat/liquid area ratio. The meat/liquid area ratio was correlated (P < 0.01, r = 0.92) with the WHC measurements obtained by conventional formulae including sample moisture. VIA combined with mmeat/liquid ratio is a rapid stable and efficient technique for measuring WHC by the press method.     

Photochemically Switchable Interconnected Microcavities for All-Organic Optical Logic Gate

Optical microcavities confine molecular luminescence and transfer it to a far longer distance than the conventional Förster resonant energy transfer process. Such cavity-mediated energy transfer is advantageous for use in optical circuitry. However, to realize all-organic optical circuits, optical gate operation with organic materials is indispensable. Here, all-organic optical gates consisting of polymer whispering gallery mode (WGM) resonators that work as the optical source, drain, and gate, which are interconnected with polymer microfiber, are demonstrated. Photoirradiation of the source sphere, as an optical input, triggers the blue fluorescence that transmits to the gate sphere through the fiber. The fiber interconnection enhances both the light confinement efficiency in the individual spheres and the light transmission efficiency between distant spheres. The gate sphere contains photoisomerizable fluorescent dye that converts, in its closed state, the blue emission into green light, which is again transmitted to the drain sphere through the fiber and lets the sphere emit red light as an output. This optical cascade is switched on and off upon photoisomerization of the dye in the gate sphere. Furthermore, an energy cascade equipped with two gate spheres works as an OR-type logic gate, demonstrating potential utility for the future all-organic and all-optical integrated devices.