Shin Nakamura

Silicone gel is widely used to encapsulate power electronic modules. The weakness of the electrical insulation is surface discharges initiated at the gel-substrate-electrode triple junction and the subsequent formation of cavities; so called electrical trees. The propagation characteristics of cavities under high frequency and fast rise time voltages, which are typical waveforms formed in power electronic modules, have not been fully understood. Thus, in this research, the influence of frequency

These results suggest that SK is a benign neoplasm where keratinocytes in a senescent condition and G1 arrest are accumulated.

The authors present a case of Lemierre's syndrome that is an uncommon septic thrombophlebitis of the internal jugular vein. A 31-year-old man developed pharyngeal pain one month before hospital admission when he suffered from a severe headache and painful swelling of the left side of his neck. He was diagnosed with tonsillitis. Contrast-enhanced computed tomography and magnetic resonance imaging of the neck revealed the presence of an occlusive thrombosis of the left internal jugular vein and an

Tonsil, extraocular muscle, and sublingual gland showed relatively high FDG accumulation, which was sometimes similar to tumor accumulation. The right-to-left ratio of SUVmax was considered useful in differentiating tumor from physiological accumulation, and the presence of tumor might be highly suspected in cases with a ratio of 1.5 or more.

This article reports the effect of temperature on tree propagation and phase resolved partial discharge (PRPD) pattern in epoxy/silica nanocomposite. The results show that tree shapes in 0-wt% and 5-wt% samples change from branch-like to bush-like as temperature rises. The tensile stress tends to decrease when the temperature is high, and a tree can select numerous paths to propagate; however, tree shapes in 10-wt% samples keep bush-like regardless of the temperature. It is suggested that nano-p

Thermal conductivities of InSb and GaSb in solid and liquid states were measured with a ceramic probe. Thermal conductivities at melting points were about 17.7 (W/mK) at 803 K for molten InSb and 21.7 (W/mK) at 993 K for molten GaSb. Thermal conductivities were slightly increased with increasing temperature in liquid state. Lorenz numbers in liquid state were 2.34×10−8 (WΩ/K2) at 803 K for InSb and 2.07×10−8 (WΩ/K2) at 993 K for GaSb.

A parallel multiplier design based on the five-counter cell is discussed. A design optimization for the performance in speed is proposed at the logic design level which is developed into an MOS circuit design. The comparison of the five-counter cell design and the full adder cell design reveals that the proposed design is most useful with pass gate logic and results in high-speed multiplication (approximately twice as fast as that of the full adder design) with a moderate increase in hardware co

A new ceramic probe has been developed for measuring the thermal conductivity of an electrically conductive liquid by using the transient hot wire method. A wire was fabricated on a 10-mm-thick alumina substrate using a co-firing technique. To avoid leakage of the current to the liquid, the metallized wire was insulated with a 60-μm-thick alumina layer. Also developed for this probe is a method of compensating for the measurement error caused by increases in the resistance of metallized electrod

We investigated the performance of electric-field-induced second-harmonic generation (E-FISHG) by spectroscopic measurement using high-intensity femtosecond laser pulses. The second-harmonic intensity increased quadratically versus the applied electric field, as expected from the theory, up to 15 kV/cm with the laser energy up to 2.5 mJ, which is ∼5 times higher than the observable optical breakdown threshold. In addition, when the laser energy was 2.8 mJ, ∼80 times signal intensity at 0.23 mJ w