Effects of heated seats in vehicles on thermal comfort during the initial warm-up period

Eight subjects participated in a subjective experiment of eight conditions to investigate the effects of heated seats in vehicles on skin temperature, thermal sensation and thermal comfort during the initial warm-up period. The experimental conditions were designed as a combination of air temperature in the test room (5, 10, 15, or 20 °C) and heated seat (on/off). The heated seat was effective for improving thermal comfort during the initial warm-up period when air temperature was lower than 15 °C. Use of heated seats prevented decreases in or increased toe skin temperature. Heated seats also increased foot thermal sensation at 15 and 20 °C. Optimal thermal sensation in contact with the seat was higher when air temperature was lower. Optimal skin temperature in contact with the seat back was higher than that with the seat cushion. Moreover, these optimal skin temperatures were higher when air temperature was lower.     

A coaxial pulsed plasma thruster using chemical propellants

Pulsed plasma thrusters (PPTs) have the advantages of mechanical simplicity and robustness compared to other electric propulsion systems. However the thrust power ratio of PPTs is lower than that of other electric propulsion systems. To enhance the thrust performance of the PPT, we propose to use several combustible solid chemicals as coaxial PPT propellants to replace Teflon^® (Polytetrafluoroethylene: PTFE). With the design, the force obtained thermodynamically is expected to augment the PPT thrust power ratio with the help of the chemical energy contained in the propellants. As a result, the thrust power ratio is increased using hydroxyl-terminated polybutadiene-ammonium perchlorate (HTPB-AP)-based propellants compared to the case of ordinary Teflon. The discharge current and voltage waveform does not change even when the propellant is changed. These findings could indicate that the impulse bits by gasdynamic contribution are lager in the case of chemical solid propellants than in the case of Teflon.     

Integrable multimode interference distributed Bragg reflector laser all-optical flip-flops

A novel fully integrable all-optical flip-flop has been created using distributed Bragg reflector multimode interference bistable laser diodes. The single metal-organic vapor phase epitaxy regrowth offset quantum well structure active/passive integrated flip-flop lases in single mode at 1554 nm and is compatible with standard fabrication methods of InP photonic integrated circuits (PICs). All-optical reset switching through cross-gain saturation was demonstrated over a 52-nm range, at 1522-1574 nm. An optical set has been achieved with -3 dBm and optical reset with less than -5-dBm external light injection. The flip-flop will be useful for integration in PICs of future photonic systems for self-routing and optical memories or buffers.     

A 63-mW H.264/MPEG-4 audio/visual codec LSI with module-wise dynamic Voltage/frequency scaling

A single-chip H.264 and MPEG-4 audio-visual LSI for mobile applications including terrestrial digital broadcasting system (ISDB-T / DVB-H) with a module-wise, dynamic voltage/frequency scaling architecture is presented for the first time. This LSI can keep operating even during the voltage/frequency transition, so there is no performance overhead. It is realized through a dynamic deskewing system and an on-chip voltage regulator with slew rate control. By the combination with traditional low power techniques such as embedded DRAM and clock gating, it consumes only 63 mW in decoding QVGA H.264 video at 15 frames/sec and MPEG-4 AAC LC audio simultaneously.     

高性能粉末冶金材料与其制造工艺的开发

随着常规粉末冶金产业发展，像锻轧粉末冶金铝合金、超塑性高温合金、机械合金化氧化物弥散强化（ODS）合金之类的先进粉末冶金工艺，引起了人们的注意。受先进粉末冶金工艺启发，开发了适应日本汽车与家电产业的新材料与生产工艺，开发了适合于钢铁结构的粉末冶金Al-Si-X合金。为了改进经济性与近终形（NNS）成形性，开发了无包套粉末挤压工艺与精压式粉末锻造工艺。基于这些工艺，还开发了比单一结构材料具有较多功能的新材料，诸如轻量散热器（heat sink）与高性能发动机气缸内衬。     

Magnetization Reversal by Electrical Spin Injection in Ferromagnetic (Ga,Mn)As-Based Magnetic Tunnel Junctions

We report current-induced magnetization reversal in a ferromagnetic semiconductor-based magnetic tunnel junction (Ga,Mn)As/AlAs/(Ga,Mn)As prepared by molecular beam epitaxy on a p-GaAs(001) substrate. A change in magneto-resistance that is asymmetric with respect to the current direction is found with the excitation current of 10⁶ A/cm². Contributions of both unpolarized and spin-polarized components are examined, and we conclude that the partial magnetization reversal occurs in the (Ga,Mn)As layer having smaller magnetization with the spin-polarized tunneling current of 10⁵ A/cm².     

Development of smart composite structures with small-diameter fiber Bragg grating sensors for damage detection: Quantitative evaluation of delamination length in CFRP laminates using Lamb wave sensing

The authors and Hitachi Cable, Ltd. have recently developed small-diameter optical fiber and its fiber Bragg grating (FBG) sensor for embedment inside a lamina of composite laminates without strength reduction. The outside diameters of the cladding and polyimide coating are 40 and 52 μm, respectively. First, a brief summary is presented for applications of small-diameter FBG sensors to damage monitoring in composite structures. Then, we propose a new damage detection system for quantitative evaluation of delamination length in CFRP laminates using Lamb wave sensing. In this system, a piezo-ceramic actuator generates Lamb waves in a CFRP laminate. After the waves propagate in the laminate, transmitted waves are received by an FBG sensor attached on or embedded in the laminate using a newly developed high-speed optical wavelength interrogation system. This system was applied to detect interlaminar delamination in CFRP cross-ply laminates. When the Lamb waves passed through the delamination, the amplitude decreased and a new wave mode appeared. These phenomena could be well simulated using a finite element analysis. From the changes in the amplitude ratio and the arrival time of the new mode depending on the delamination length, it was found that this system could evaluate the delamination length quantitatively. Furthermore, small-diameter FBG sensors were embedded in a double-lap type coupon specimen, and the debonding progress could be evaluated using the wavelet transform.     

Plan for first phase of safety demonstration tests of the High Temperature Engineering Test Reactor (HTTR)

Safety demonstration tests using the High Temperature Engineering Test Reactor (HTTR) will be conducted for the purpose of demonstrating inherent safety features of High Temperature Gas-cooled Reactors (HTGRs) as well as providing the core and plant transient data for validation of HTGR safety analysis codes. The first phase safety demonstration test items include the reactivity insertion test and the coolant flow reduction test. In the reactivity insertion test, which is the control rod withdrawal test, one pair out of 16 pairs of control rods is withdrawn, simulating a reactivity insertion event. The coolant flow reduction test consists of the partial loss of coolant flow test and the gas circulators trip test. In the partial loss of coolant flow test, primary coolant flow rate is slightly reduced by control system. In the gas circulators trip test one and two out of three gas circulators are run down, simulating coolant flow reduction events. The gas circulators trip tests, in which position of control rods are kept unchanged, are simulation tests of anticipated transients without scram (ATWS).     

Interior permanent magnet linear synchronous motor forhigh-performance drives

Permanent magnet linear synchronous motors have been developed for factory automation, transportation applications, and so on. In the rotary-type permanent magnet synchronous machines, the wide speed and constant power operation are realized by using the reluctance torque due to the saliency and the flux-weakening control. In this paper, we examine the effect of the interior permanent magnet arrangement for wide speed operation and the end effect in the linear structure