A novel method to fabricate uniform epitaxial graphene on C-face SiC substrates was investigated. Graphene was grown on the C-face 6H-SiC substrates with a sputtered SiC film by annealing temperatures ranging from 1400 to 1900 °C under an Ar ambient. The fractional area of the graphene having the layer number of two was about 95% in a 75×75 μm square by a Raman mapping and a low energy electron microscopy. Graphene on the C-face SiC fabricated by this method is quite uniform compared to that made by a conventional method without the sputtered SiC films and is thus suitable for high frequency analog devices.

Low-cost, compact, and accurate systems for in-home rehabilitation are needed in aging, aged, and hyper-aged groups. In this study, we developed an in-home rehabilitation system for patients with balance disorders by providing visual feedback of postural information in real-time. Our system measures the user's whole body motion and the center of pressure (COP) using a Kinect and Wii Balance Board (WBB). The accuracy of body motion for estimating the anterior folding and lateral bending angles was validated experimentally by comparing the estimates with the angles given by an optical motion capture system. Additional experiments showed that the COP has a small correlation coefficient with the angles, suggesting that WBB is necessary for measuring the COP.

A 60 GHz tandem coupler using offset broadside coupled lines is proposed in a WLP (Wafer Level Packaging) technology. The fabricated coupler has a core chip area of 750 μm × 385 μm (0.288 mm2). The measured results show an insertion loss of 0.44 dB, an amplitude imbalance of 0.03 dB and a phase difference of 87.6° at 60 GHz. Also the measurement shows an insertion loss of less than 0.67 dB, an amplitude imbalance of less than 0.31 dB, a phase error of less than 3.7°, an isolation of more than 29.7 dB and a return loss of more than 27.9 dB at the input ant coupled ports and more than 14.3 dB at the direct and isolated ports over the frequency band of 57-66 GHz, covering 60 GHz band both in Japan and US. To the best of our knowledge the proposed coupler achieves the lowest ever reported insertion loss and amplitude imbalance for a 3-dB coupler on a silicon substrate. With its superior performance and lower cost compared to the CMOS counterparts, the proposed coupler is a suitable candidate for low-cost high-performance millimeter-wave systems.

A magnetic refrigeration test was performed using a test device filled with spherical GdN material synthesized by the hot isostatic pressing (HIP) method. Refrigeration with an active magnetic regenerator cycle was tested in the temperature range between 48 and 66 K, with the field changing from 1.2 to 3.7 T and 2.0 to 4.0 T at upper and lower sides of the regenerator bed filled with the GdN spheres, respectively. Temperature spans about of 2 K were obtained at both sides, and the total temperature span in each cycle attained about 5 K. The specific heat of the material was measured to calculate the magnetic entropy change ΔS and the adiabatic temperature change ΔT induced by the magnetic field change ΔH. It was suggested that for a given ΔH, larger ΔS and ΔT can be exploited when demagnetized to lower H, especially, to zero field.

In the recent development of the studies in iron-based superconductors, high-pressure experiments have been played an important role. Large enhancement of Tc with applying pressure and pressure-induced superconductivity were reported in LaFeAsO1-xFx. In this work, electrical, magnetic and structural measurements on 1111 type Ca(Fe1-xCox)AsF and 11 type Fe(Se1-xTex)0.92 under high pressure have been performed. For Ca(Fe1-xCox)AsF, the substitution of Co suppressed the magnetic and structural transitions and raised superconductivity. Pressure-induced superconductivity was observed for x = 0.0 and 0.05. The highest Tc was obtained in parent compound under high pressure, in contrast to LaFeAsO1-xFx. These results suggest that the substitution of Co increases carrier concentration and induces disorder in the FeAs superconducting layer. For FeTe0.92, pressure-induced superconductivity was not detected under high pressure up to 19 GPa, although the resistive anomaly due to the structural and magnetic phase transition was suppressed by applying pressure.

A series of novel ionic chromophores consisting of a carbazole moiety and pyridinium rings connected by a double bond have been designed and synthesized as nonlinear optical materials. Their linear and nonlinear optical properties were investigated by semiempirical calculation and experiment. The absorption maximum wavelengths (lmax) of these ionic chromophores showed shifting to longer wavelength region than their corresponding electrically neutral compounds. These ionic chromophores possess large first hyperpolarizabilities (b).

We propose a new structure of vertical a-Si FET with the intermediate layer between the source and drain consisting of the multi-layer structure. The mechanism of off-current in short-channel vertical-type a-Si FET is discussed. The multilayered structure is incorporated in an attempt to reduce the back gate effect. The preliminary experimental results are also presented.