Characterizing landscape changes in central Rondonia using Landsat TM imagery

An analysis of landscape changes in a region of pioneer settlements in central Rondonia, western Brazilian Amazon, was derived from Landsat TM data. Total deforested area increased from 206 x 103 ha in 1977, to 565 x 103 ha in 1985 and to 1210 x 103 ha, or 35.5% of the region, in 1995. Eighty-one per cent of the total 1995 deforestation had occurred in regions within 12.5km from areas of pioneer colonization deforested by 1977. Deforested area exceeded 79% in regions within 12.5km from the region's first road.     

Electric double‐layer capacitor module with series‐parallel reconfigurable cell voltage equalizers

When electric double‐layer capacitors (EDLCs) are connected in series, a cell voltage imbalance occurs due to nonuniform cell properties. Cell voltage imbalance should be minimized to prolong cycle lives and maximize the available energy of cells. In this study, we propose a series‐parallel reconfigurable cell voltage equalizer that is considered suitable for energy storage systems using EDLCs instead of traditional secondary batteries as the main energy storage sources. The proposed equalizer requires only EDLCs and switches as its main circuit elements, and it utilizes EDLCs not only for energy storage but also for equalization. An equivalent circuit model using equivalent resistors that can be regarded as an index of equalization speed is developed. Current distribution and cell voltage imbalancing during operation are quantitatively generalized. Experimental charge–discharge tests were performed on the EDLC modules to demonstrate the performance of the cell voltage equalizer. All the cells in the modules could be charged/discharged uniformly even when a degradation‐mimicking cell was intentionally included in the module. The resultant cell voltage imbalances and current distributions were in good agreement with those predicted by mathematical analyses. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(4): 38–50, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21287     

Error grid analysis of noninvasive glucose monitoring via gingival crevicular fluid.

In order to realize a noninvasive blood glucose monitor, we monitored the gingival crevicular fluid (GCF). In this paper, the clinical evaluations were performed on not only normal subjects but also diabetic subjects using a GCF-glucose monitor to determine blood glucose levels. Meal load tests were carried out and the time-course changes in blood glucose level and GCF glucose level were measured continuously. A positive correlation of more than 0.9 was found between blood glucose level and GCF glucose level, necessitating the calibration of individual correlations for every subject. Finally, the performance of the GCF-glucose monitor was evaluated using Error Grid Analysis. As the results, significant information for the glucose level decision was obtained not only for normal subjects, but also for diabetic subjects.     

Assessing material qualities and efficiency limits of III–V on silicon solar cells using external radiative efficiency

The paper presents a quantitative approach to the investigation and comparison of the material qualities of III–V on silicon (III–V/Si) solar cells by using external radiative efficiencies. We use this analysis to predict the limiting efficiencies and evaluate the criteria of material quality in order to achieve high‐efficiency III–V/Si solar cells. This result yields several implications for the design of high‐efficiency III–V/Si solar cells. Copyright © 2016 John Wiley & Sons, Ltd.     

Sandwich-type ferromagnetic RF integrated inductor

The first demonstration of a sandwich-type ferromagnetic RF integrated spiral inductor for the 2-GHz range is reported. Two ferromagnetic CoNbZr films were set to sandwich the spiral in order to enhance the amount of magnetic flux linkage across the coil current. The stresses given from the insulator to the ferromagnetic film were studied. The inductance L of 7.9 nH and the qualify factor Q of 12.7 were obtained for a 200 μm×400 μm size four-turn rectangular spiral at f=2 GHz. The inductance was better than that of an air core of the same coil size by 19%, and the Q was better by 23%. Comparison with the on-top magnetic film type was also discussed     

Techniques for flexible image/video resolution conversion with heterogeneous terminals

Multimedia capturing and display devices of different resolutions and aspect ratios can be easily connected by networks and, thus, there is a great need to develop techniques that facilitate flexible image/video format conversion and content adaptation among these heterogeneous terminals. Quality degradation due to downsampling, up-sampling, coding/decoding, and some content adaptation mechanism (say, image mosaicking) in the transmission process is inevitable. It is desirable that multimedia contents can be easily captured, displayed, and seamlessly composed. Challenges and techniques to achieve this goal are reviewed first. Then, two specific topics, i.e., image/video mosaicking and super resolution (SR) conversion, are highlighted. As compared with previous work developed for these problems, the challenge under the current context is to strike a balance between low computational complexity and high quality of resultant image/video. Several new developments along this line are discussed     

Spot-size converter integrated semiconductor optical amplifiers foroptical gate applications

A spot-size converter integrated semiconductor optical amplifier (SSC-SOA) was developed as a gate element in an optical switch matrix for photonic switching applications. By a selective metal-organic vapor phase epitaxy technique, a bulk InGaAsP stripe, including an active region and thickness tapered SSCs, was grown. Wavelength composition of the stripe, strain on the stripe, and electrode coverage above the SSC region were optimized. As a result, gate operation for fiber-to-fiber gain of 0 dB was achieved at a low injection current of 30 mA, and the polarization dependence of the gain was eliminated as well     

Characterization of interfacial reaction and chemical bonding features of LaOx/HfO2 stack structure formed on thermally-grown SiO2/Si(1 0 0)

A stack structure consisting of ～1.5 nm-thick LaO_x and ～4.0 nm-thick HfO₂ was formed on thermally grown SiO₂ on Si(1 0 0) by MOCVD using dipivaloymethanato precursors, and the influence of N₂ annealing on interfacial reaction for this stack structure was examined by using X-ray photoelectron spectroscopy and Fourier transform infrared attenuated total reflection. We found that compositional mixing between LaO_x and HfO₂ becomes significant from 600 °C upwards and that interfacial reaction between HfLa_yO_z and SiO₂ proceeds consistently at 1000 °C in N₂ ambience.     

Wavelength-independent operation of EA-modulator integratedwavelengthselectable microarray light sources

In this letter, we have simultaneously fabricated five wavelength-selectable microarray light sources (WSLs), each having a different wavelength range integrated with an electroabsorption (EA) modulator on a single wafer. We also introduced a novel device configuration scheme for wavelength-independent modulation. The five EA-WSLs fully covered the entire C-band and had a low uniform threshold current of 6 ± 1 mA at 25°C. Wavelength-independent extinction characteristics were obtained over a tuning wavelength range of 8 nm, and 2.5-Gb/s transmission over 600 km was successfully achieved