Involvement of the supramammillary nucleus in aversive conditioning.

Mechanisms for the retention and retrieval of conditioned taste aversions (CTAs) have yet to be fully defined. The authors explored relevant subcortical forebrain regions by tracking the expression of immediate early genes, c-fos and zif268. The supramammillary nucleus (SuM) was activated following both viscerally based CTA and somatically based inhibitory avoidance (IA). Excitotoxic lesions of the SuM before conditioning caused no disruption of acquisition but accelerated the extinction of both the CTA and IA. In contrast, lesions after CTA conditioning did not impair retention or retrieval. The present study indicates that the SuM is activated by memory-elicited discomfort during retrieval, suggesting that it plays a role in resisting the extinction of a long-term aversive memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of laser-induced plume on penetration in laser welding

The influence of a laser-induced plume on penetration is discussed in remote laser welding. Melt-runs accompanying plumes of various lengths were carried out in order to investigate the influence of plume on penetration using a 4.5 kW YAG laser and air knife. Penetration depth obviously reduced in conditions with a long plume. It is considered that the decrease of penetration depth comes from attenuation of laser power in the plume, through the decrease in weld metal cross-sectional area. Attenuation of laser power was estimated at about 7% and focus shift was estimated to be about 0.7 mm in the experimental conditions with a plume of 90-mm length, compared with the conditions with a plume of 11-mm length.     

Characteristic and mechanism of pressure fluctuation caused by self-induced oscillation of supersonic impinging jet

When the underexpanded supersonic jet impinges on the obstacle, it is well known that the self-induced flow oscillation occurs. This oscillation depends on the pressure ratio in the flowfield, the position of an obstacle and is related with the noise problems of aeronautical and other industrial engineering. The characteristic and the mechanism of self-induced flow oscillation, have to be clarified to control various noise problems. But, it seems that the characteristics of the oscillated flowfield and the mechanism of an oscillation have to be more cleared to control the oscillation. This paper aims to clarify the effect of the pressure ratio and the obstacle position and the mechanism of self-induced flow oscillation by numerical analysis and experiment, when the underexpanded supersonic jet impinges on the cylindrical body. From the result of this study, it is clear that occurrence of the self-induced flow oscillation depends on the pressure balance in the flowfield.     

Development of a voltage sag detection method for nonutility generation systems

This paper deals with a new detection method based on three‐phase vector operation for voltage sag. The detection method is applicable to a protection system using a high‐speed interruption system which protects distributed generators and critical loads in a customer's facility. The algorithm and merits of this method are explained in detail. The detection characteristics are then analyzed using the ATP (Alternative Transients Program) and are confirmed using a real‐time digital simulator, and it is shown that the method is useful for detecting voltage sag. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(4): 34–41, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20117     

Protection of Lactobacillus acidophilus from the low pH of a model gastric juice by incorporation in a W/O/W emulsion

The protective effect of a W/O/W emulsion for Lactobacillus acidophilus from a model gastric juice was investigated in order to develop a method for utilizing the advantages of the probiotics. The bacteria were included in the inner-phase solution of the W/O/W emulsion, and a method for counting the viable-bacteria included in the W/O/W emulsion was developed. The relative viability of the bacteria included in the W/O/W emulsion was 49% at 2 h in the model gastric juice, whereas the viability of the bacteria directly dispersed in the juice declined to 1.3% even at 0.67 h. The relative viabilities of the encapsulated bacteria in the model gastric juice at 2 h were 0.12 and 1.10 for the emulsions having the median diameters of 11.9 and 25.4 μm, prepared with inner-phase volume ratios at 0.03 and 0.45, respectively. The relative viabilities of the bacteria in the W/O/W emulsions with the median diameters of 11 and 27 μm, prepared at the homogenization speed of 2.2×10⁴ and 9.8×10³ rpm, were 0.4 and 0.8, respectively. These results suggested that both the inner-phase volume ratio and the median diameter of oil droplet affected the relative viability of the included bacteria.     

High Electrical Conductivity and High Fracture Strength of Sc2O3-Doped Zirconia Ceramics with Submicrometer Grains

The microstructure, crystal phase, electrical conductivity, and mechanical strength of less than 7-mol%-Sc₂O₃-doped zirconia ceramics fabricated by comparatively low-temperature sintering at 1200–1300°C for 1 h were investigated. Zirconia ceramics having a uniform microstructure (grain size < 0.5 μm) stabilized with 6 mol% Sc₂O₃ showed high electrical conductivity (0.15 S/cm at 1000°C) and high fracture strength (660 MPa). With the increase of Sc₂O₃ content from 3.5 to 7 mol%, the grain size, fracture strength, and electrical conductivity at 1000°C changed from 0.2 to 0.5 μm, 970 to 440 MPa, and 0.07 to >0.2 S/cm, respectively. Sc₂O₃-doped zirconia polycrystals with high fracture strength and high electrical conductivity are promising candidates for the electrolyte material of solid oxide fuel cells.     

Design guidelines of a flux‐lock superconducting fault current limiter with ac magnetic field coil for a 6.6‐kV distribution system

We have proposed a new type of fault current limiter, which consists of a flux‐lock reactor with high‐Tc superconducting (HTS) elements and an ac magnetic field coil (Flux‐Lock‐Type Fault Current Limiter: FLT‐FCL). The FLT‐FCL can increase both the current capacity and the limiting impedance by means of a transformer action and an ac magnetic field application mechanism. This paper reports the conceptual design of an FLT‐FCL for application to a 6.6‐kV/200‐A distribution system. Theoretical expressions for the current limiting behavior are derived and the new concept of “quench power” is proposed in order to estimate the required number of HTS elements for two types of FLT‐FCL and for a basic FCL type consisting only of HTS elements. Design guidelines for the FLT‐FCL are derived from the calculation results. © 2001 Scripta Technica, Electr Eng Jpn, 135(4): 17–25, 2001     

Characteristics of Compression Wave Caused by Reflection of Expansion Wave at Open End of Tube

When an expansion wave propagated along a constant area straight tube reaches at the open end, the negative impulsive wave and the compression wave are formed by the emission and reflection of expansion wave. The negative impulsive wave is emitted toward the surrounding area and causes an impulsive noise like the sonic boom. The compression wave propagates in the tube toward the upstream and may cause the impulsive noise at the surrounding area of tube portal. With the advance of industrial engineering, it seems that the discharging of the expansion wave will become important problems. In this study, the experimental and numerical investigations are carried out using the shock tube and the TVD numerical method. The formation process of compression wave near the open end, the relationship with the compression wave and the expansion wave and the characteristics of compression wave are discussed.     

First trial of the electric power transmission of 3.8 kV–460 kVA through the prospective power transmission model system integrated under superconducting environment (PROMISE)

Superconducting technology is regarded as a breakthrough to future electric power transmission because of its highly densified and large transmission capability. This paper proposes a concept of the future power system composed of various superconducting apparatuses. A prototype model system called “PROMISE (PROspective power transmission Model system Integrated under Superconducting Environment)” is constructed to prove the realization of the above concept. PROMISE is composed of a superconducting transformer (60 Hz, 6/3 kV, 1000 kVA class), superconducting fault current limiter (6 kV, 200 A class), and superconducting power cable (5 m, 6 kV, 650 A class). This paper also shows that PROMISE realized the transmission of the electric power of 3.8 kV–460 kVA (50 Hz). This is the first achievement in the world. The voltage-current synthetic test verified that PROMISE can withstand ac voltage of 6 kV while carrying ac current of 170 A (60 Hz). The ac loss of superconducting cables, the heat leak of cryostat and the core loss of the superconducting transformer are measured to estimate the transmission loss of PROMISE. These fundamental performances of PROMISE may indicate the feasibility of the future introduction of superconducting technology for electric power systems.     

Coupling stimuli-responsive magnetic nanoparticles with antibody-antigen detection in immunoassays

Because current homogeneous immunoassays show some limitations, particularly low sensitivity, we developed a new immunoassay to overcome these limitations. The approach was based on magnetic nanoparticles with a thermoresponsive polymer layer, a negatively charged polymer, and streptavidin-biotin-based antibody-antigen detection and yielded higher sensitivity than commonly used heterogeneous immunoassays. Because no special equipment is needed, it can be applied to currently available absorbance-based systems for high-throughput assays.