Effect of green compact structure on the sintering of alumina

The effect of particle agglomeration on sintering has been studied by slipcasting suspensions with pH values ranging from 2 to 11. The rate of densification has been found to depend on the degree of agglomeration. Complete dispersion of alumina primary particles has not been attained through adjustment of pH of suspensions, and agglomerates also remained in the best-dispersed suspension. Elimination of the agglomerates by sedimentation lowered the densification temperature of slip-cast compacts. The grain size-density curve is a function of temperature. High-density and small-grained sintered bodies were obtained by low-temperature long-time firing.     

Microstructure Development and Dielectric Properties of Potassium Strontium Niobate Ceramics

Sintering of a KSr₂Nb₅O₁₅ powder compact at 1350°C resulted in a duplex structure. Prefiring of the compact between 1200° and 1300°C inhibited the abnormal grain growth responsible for the duplex structure. The Curie temperature and dielectric constant were dependent on the microstructure.     

Error grid analysis of noninvasive glucose monitoring via gingival cerevicular fluid

In order to realize a noninvasive blood glucose monitor, we monitored the gingival cerevicular 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.     

Observation of iron silicide formation by plan-view transmission electron microscopy

The formation and the phase transitions of iron silicide by solid-phase epitaxy have been investigated by means of plan-view transmission electron microscopy, which enables us to observe a clean interface between Fe and Si. Layers of Fe were deposited on Si (100) at room temperature in an ultrahigh vacuum chamber. The sample was annealed in the electron microscope at a temperature between 673 and 1073 K. After annealing at 673 K, FeSi crystallites were formed with various orientations. When the annealing temperature was increased to 973 K, we found that the crystallites suddenly started to coalesce into grains of several hundreds of nanometers in size and polycrystalline beta-FeSi2 was formed. These phase transitions were also confirmed with electron energy-loss spectroscopy.     

Modulator integrated DFB lasers with more than 600-km transmission capability at 2.5 Gb/s

The modulator integrated DFB laser diodes with more than 600-km transmission capability over normal fiber at 2.5 Gb/s, have been reproducibly achieved. The longest transmission length obtained in the experiment is as long as 800 km.     

Reduction of wave propagation loss by mesh in rectangular tunnels

The reduction of radio wave attenuation in rectangular tunnels is discussed. The attenuation of the dominant mode due to its field penetration into a lossy dielectric wall is reduced by means of the attachment of wire netting (mesh). First, a reflection coefficient from a mesh screen over a lossy surface is analytically evaluated. Then, based on a geometrical optical approach to the propagation model in tunnels, the attenuation of the dominant mode in a rectangular tunnel is derived using the reflection coefficient. The calculated attenuation constants are in good agreement with experimental ones obtained in a laboratory. Finally, the efficiency of attenuation reduction rate by the mesh shielding method is summarized as a function of spatial ratio of the mesh wire interval divided by the wavelength. It is shown that the efficiency of reduction rate by mesh is significant     

CAD-compatible high-speed CMOS/SIMOX gate array using field-shieldisolation

A specific 0.5 μm CMOS/SIMOX technology was developed for a gate array/sea of gate (SOG) using field-shield (FS) isolation to overcome a pending problem of source-to-drain breakdown voltage (BV_ds) lowering. FS isolation is capable of improving BV_ds because surplus holes generated by impact ionization at the drain region are collected through the body region under the FS gate. BV_ds was maintained at a level of junction breakdown before reaching the punchthrough limitation at a gate length of around 0.3 μm using the FS isolation. The FS isolation technique was successfully applied to an SOG gate array on a SIMOX substrate. The gate array has the same area as that on the bulk-Si and is compatible to a conventional bulk-Si CAD system because the layout is basically the same. A 53-stage ring oscillator fabricated on the FS isolated SOG gate array exhibited 1.7 times higher speed operation than that on a bulk-Si counterpart, keeping low power consumption characteristics up to a drain voltage of 3 V     

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.     

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