Ag deposition-based multicolor electrochromic (EC) device we reported can switch various optical states among transparent, black, silver, cyan, magenta, and yellow by only using electrochemical deposition of Ag. However, the EC device had poor color retention property under open-circuit state because of dissolution of deposited Ag metal by Cu2+ ions, which is essential because it acts as redox material at counter electrode. Here, we introduced an anion exchange membrane to separate Cu2+ from the Ag deposit. The improved device achieved longer retention time of colored state. It is effective to maintain the coloring state without electric power for practical application.

To improve the understanding of the mechanism driving recent changes in outlet glaciers in East Antarctica, we measured changes in the terminus position, ice flow velocity and surface elevation of the Langhovde Glacier located on the Sôya Coast. From satellite images from 2000–12 and field measurements taken in 2012 the glacier terminus position and flow velocity showed little change between 2003 and 2007. After this quiescent period, the glacier progressively advanced by 380 m and the flow velocity increased near the calving front by 10 m a-1 from 2007–10. No significant change was observed in surface elevation during the study period. The changes in the terminus position and flow velocity imply a reduction in the calving rate from 93 m a-1 (2003–07) to 16 m a-1 (2007–10). This suggests that calving was inhibited by stable sea ice conditions in the ocean. Theses results indicate that the Langhovde Glacier was in a relatively stable condition during the study period, and its terminus position was controlled by the rate of calving under the influence of sea ice conditions.

We demonstrated electrical characteristics of operational amplifier (OPAMP) circuits fabricated by GaN/AlGaN/GaN HEMTs operating over 100 oC. GaN/AlGaN/GaN HEMTs, with the extremely low source resistance were fabricated by multiple ion implantation, precisely controlled ion-implanted (I/I) resistors and Schottky barrier diodes were integrated on the silicon substrate. The GaN cap layer on the AlGaN was grown to decrease the gate leakage current and current collapse for AlGaN/GaN HEMTs.

Multiple ion-implanted GaN/AlGaN/GaN high electron-mobility transistors (HEMTs) and preciously controlled ion-implanted resistors integrated on silicon substrate are reported. Using ion implantation into source/drain (S/D) regions, the performances were significantly improved. On-resistance reduced from 10.3 to 3.5 Ω•mm. Saturation drain current and maximum transconductance increased from 390 to 650 mA/mm and from 130 to 230 mS/mm. Measured transfer curve shows that I/O gain of 4.5 can be obtained at Vdd = 10 V.

We demonstrate the realization of compatibility of extremely low gate leakage current and low source resistance with Si ion-implanted (I/I) GaN/AlGaN/GaN surface-stabilized high-electron mobility transistor (HEMT) without any recess etching process. The source/drain regions were formed using Si ion implantation into undoped GaN/AlGaN/GaN on sapphire substrate. Using ion implantation into source/drain (S/D) regions with energy of 80 keV, the performances were significantly improved. On-resistance (Ron) reduced from 105 to 9.2 Ω·mm. Saturation drain current (Idss) and maximum transconductance (gmMAX) increased from 49 to 527 mA/mm and from 13 to 84 mS/mm (Vg=+1V).

We investigated the feasibility of using multi-polarization Synthetic aperture radar (SAR) data to estimate the thickness of undeformed first-year ice. Analysis of the radar Signatures for the C- and L-bands Showed that the correlation between the ice thickness and VV-to-HH backscattering ratio is larger than the correlation between the ice thicknesses and the backscattering coefficients. This is in part because the ice Surface Salinity and hence the Surface reflection coefficient decreases as the ice thickens. The backscattering ratio had low Sensitivity to the Small-scale ice Surface roughness for the C-band and is almost independent of roughness at L-band. Given that the ratio is most Sensitive to ice Surface dielectric constants, which depend on Salinity, we developed an algorithm for retrieving the ice thickness that is based on the backscattering ratio and on the integral-equation-method (IEM) Surface Scattering model. Comparison of the observed and estimated ice thicknesses Showed that the correlation was much better when the thicknesses were estimated using the backscattering ratio than when the backscattering coefficient was used directly. The algorithm also performed better than previous retrievals using an empirical technique.

Incorporation of Si ion implantation to GaN metal semiconductor field effect transistor (MESFET) processing has been demonstrated. The channel and source/drain regions formed using Si ion implantation into undoped GaN on sapphire substrate. In comparison with the conventional devices without ion implanted source/drain structures, the ion implanted devices showed excellent device performance. On-state resistance reduces from 210 Ω-mm to 105 Ω-mm. Saturation drain current and maximum transconductance increase from 36 mA/mm to 78 mA/mm and from 3.8 mS/mm to 10 mS/mm, respectively.

Ti/Al ohmic contact with an extremely low specific contact resistance has been formed by the deposition of Ti and Al films on Si+ lanted GaN. The ohmic contact formed by annealing at 600 o C of Ti film with a thickness of 50 nm and Al film with a thickness of 200 nm reveals the good smooth surface and uniform structure as compare to those of contacts formed above 700 °C, which is correlated to whether the Al-Ti alloy is melted during the annealing of ohmic contact or not. The specific contact resistance of 2 × 10-6Ω-cm2 is obtained for Si+ implanted GaN with a dose of 5 × 1013 cm-2. As Si ion dose increases to 5 × 1014 /cm2, the specific contact resistance is reduced to 2 × 10-8 Ω-cm2. It is revealed that the selective doping at high impurity concentration in the surface region by Si+ implantation is useful to reduce the contact resistance for Ti/Al contact to GaN.

Multi-frequency, multi-polarization airborne synthetic aperture radar (SAR) observations of sea ice in the southern Sea of Okhotsk were carried out in February 1999 in conjunction with RADARSAT SAR observations. The final goal of this study is to clarify the backscattering characteristics and to understand the scattering mechanisms of sea ice in the Sea of Okhotsk by using microwave multiparametric SAR. The airborne SAR (Pi-SAR) has two frequencies (X- and L-band) and multi-polarization (HH, VV, HV, VH) with 1.5 m (X-band) and 3.0 m (L-band) resolution. It was developed by the Communications Research Laboratory (X-band) and the National Space Development Agency of Japan (L-band). We show the frequency dependence and polarization properties of radar backscattering from sea ice. We find that it is possible to distinguish ice types by comparing backscattering from sea ice in the X- and L-bands. Investigation of the polarization characteristics at X-band was very useful for detecting the thin-ice area (e.g. nilas and gray ice).

We have acquired ground-truth data at Lake Saroma, northeast Hokkaido, Japan, and the surrounding area since 1993 in order to collect data on regional sea ice in the Sea of Okhotsk. The data were acquired in 1999 by polarimetric and interferometric SAR (Pi-SAR), the dual-frequency, fully polarimetric airborne SAR system jointly developed by the National Space Development Agency of Japan (NASDA) and the Communications Research Laboratory (CRL), simultaneously with ground experiments. This paper describes the results of polarimetric data analysis of typical sea ice observed in the offshore region near Lake Saroma. The polarimetric parameters used were correlation coefficient and phase difference. Based on the analysis of these parameters, we found that the correlation coefficient between RR and LL polarizations can discriminate four categories including three types of ice and open water.