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We studied on the anticorrosion effect by applying silane type surface penetrants on RC degraded by carbonation. Two types of carbonation residue and two types of environmental conditions after accelerated carbonation were prepared and investigation was made on the corrosion behaviour of reinforcing bars by applying surface penetrants. As a result, by blocking water penetration by applying surface penetrants, there was a difference in anticorrosive effect in the behaviour of half-cell potential, polarization resistance, and investigation of reinforcing bar corrosion after the end of exposure. From the above, this paper reports on the possibility of realizing anticorrosion effect by suppressing invasion of moisture from concrete surface to carbonated RC.

Ultrasonically assisted hydrothermal synthesis of PZT thin films was performed using an ultrasonic transducer integrated into the lid of an autoclave. Direct ultrasonic irradiation of 23 W at 53 kHz was carried out during the hydrothermal synthesis at a reaction temperature of 140 degrees C for 24 h. The resultant PZT thin film was characterized using scanning electron microscopy (SEM) and x-ray diffraction (XRD). The PZT thin film had fine nanoparticles of approximately 100 nm in diameter when the substrate was placed perpendicular to the plane of ultrasonic irradiation. The film exhibited predominantly (001) orientation when the substrate was placed parallel to the plane of ultrasonic irradiation.

Decreased maximal urinary concentrating ability after administration of vasopressin analogs is a sensitive indicator of some forms of nephrotoxicity. To evaluate the potential of subcutaneous injection of 1 -deamino-8-D-arginine vasopressin (desmopressin) as a provocative agent in testing maximal urinary concentrating ability, rats were administered desmopressin acetate subcutaneously and urine osmolality was measured. At all dosages used (3–300 ng/kg), urinary osmo-lality increased for the first 4 h after desmopressin administration. At dosages > 100 ng/kg, osmolality remained elevated for 8 h. The utility of desmopressin administration in detecting urinary concentrating defects was validated by pre-treating rats with sodium fluoride and measuring maximal urine concentrating ability after administration of 100 ng/kg desmopressin. Administration of 100 or 200 μmol sodium fluoride (NaF) intraperitoneally daily for 3 days, resulted in 55 and 60% decrease, respectively, in maximal urinary concentrating abili...

A temperature insensitive arrayed waveguide grating (TI-AWG) with an InGaAsP-InP material system is proposed. Less than 0.1 /spl Aring///spl deg/C temperature dependence for all eight channels was achieved for the first time even though we used the InGaAsP-InP material system. This novel characteristic is in good agreement with the design principle of the TI-AWG.

A temperature insensitive optical filter (TIOF) with InGaAsP-InP material system is proposed. Less than 0.1 /spl Aring///spl deg/C temperature dependence is achieved for the first time even though we used the InGaAsP-InP material system. By changing the optimum structure of the TIOF, blue-shift temperature characteristics are also obtained. These two novel phenomena are in good agreement with the TIOF design principle.

Multi-junction (MJ) solar cells on Si substrates are expected as low-cost and high-efficiency cells. Previously, the authors have demonstrated that GaAs-on-Si solar cells with novel structures have better radiation-resistance than GaAs and single-crystal Si space cells. In this paper, effectiveness; of novel structures such as super-lattice, strained super-lattice and Bragg reflectors upon initial performance and radiation-resistance of GaAs-on-Si cells has been studied. GaAs-on-Si cells with Bragg reflectors are found to have better radiation-resistance than those without Bragg reflectors. Insertion of super-lattice and strained super-lattice has also been found to be effective for improving initial cell performance as a result of effects of dislocation annihilation and back-surface field layer by insertion of such layers.

Efforts to grow high-quality GaAs films on Si substrates and improvements in the efficiency of GaAs-on-Si solar cells are reported. The epitaxial growth of GaAs on Si was studied using metalorganic chemical vapor deposition (MOCVD). The dislocation density in the active layer of the GaAs solar cell is significantly reduced by combining cyclic thermal annealing and the insertion of buffers such as InGaAs/GaAs and AlGaAs/GaA. This minimal dislocation density allowed a large-size and high conversion efficiency GaAs-on-Si solar cell to be fabricated with a total area of 2 cm/sup 2/ and an efficiency of 18.3% under AM0 and one-sun illumination. After 1 MeV electron beam irradiation at 1*10/sup 15/ cm/sup -2/, the GaAs-on-Si cells show a normalized efficiency of 0.83, which is larger than the 0.71 of a GaAs-on-GaAs cell. The use of GaAs-on-Si solar cells as the power source for satellites now looks feasible because this material is highly efficient, lightweight, inexpensive, and highly radiation resistant. >

8-channel WDM channel selectors were fabricated on InP substrates. A compact device size of 5.2 mm/spl times/3.6 mm is achieved with a combination of deep-ridge waveguides and buried waveguides. The device can select an arbitrary signal from WDM signals with a low crosstalk of less than -40 dB.

ACE (ammonium sulfide combined etching) is a new treatment designed for use in hydrocarbon gas RIE based fabrication of InP-based buried-heterostructure (BH) laser diodes (LD). ACE involves dipping a sample in ammonium sulfide (NH/sub 4/S/sub x/) solution at room temperature for 10 minutes and then treating it again with sulfuric acid prior to regrowth. We found that ACE improves regrowth interface quality and LD characteristics due to its ability to remove impurities incorporated during the process.

The GaAs thin-film solar cells on Si substrates (GaAs-on-Si cells) are found to show higher end-of-life efficiency than the conventional GaAs cells fabricated on GaAs substrates (GaAs-on-GaAs cells) under high fluence 1 MeV electron irradiation of more than 1/spl times/10/sup 15/ cm/sup -2/. The first space flight of them has been carried out. 48 2 cm/spl times/2 cm GaAs-on-Si cells with an average AM0 total-area efficiency of 16.9% have been evaluated using the Engineering Test Satellite (ETS-VI). The GaAs-on-Si cells have been demonstrated to be more radiation-resistant in space than GaAs-on-GaAs cells and 50 /spl mu/m thick Si cells. These results show that the GaAs-on-Si single-junction and InGaP/GaAs-on-Si multi-junction cells have great potential for space applications.

We demonstrate low‐threshold lasing at 4 K in optically pumped hemispherical In0.2Ga0.8As single‐quantum‐well microcavities. The incident threshold pump power density is 11 kW/cm2 corresponding to an absorbed power density of about 320 W/cm2, and the measured spontaneous emission factor β is about 0.01.

InGaAs quantum-well vertical-cavity surface-emitting lasers with low-Al-content p-type mirrors grown by metalorganic chemical vapor deposition (MOCVD) have have been characterized. Series resistance in p-type Al/sub x/Ga/sub 1-x/As/GaAs mirrors decreases drastically as the Al content in Al/sub x/Ga/sub 1-x/As decreases from AlAs. Air-post devices with a p-type Al/sub 0.06/Ga/sub 0.4/As/GaAs top mirror exhibit a room temperature CW threshold current of 1.8 mA at an operating voltage of 2.0 V (with a threshold power consumption at 3.6 mW). >

A new structure for a compact optical branching circuit is proposed. An asymmetric Y-branching circuit using total reflection is fabricated on an AlGaAs/GaAs wafer. Good branching operation is observed in a single-mode branching circuit with a branching angle of 45 degrees . The exact origins of loss in the branching circuit are also clarified. >

A shape memory piezoelectric actuator can maintain a piezoelectric displacement without an operating voltage. It has two stable strain states at zero voltage: a poled state and a depoled state. The driving principle of the shape memory piezoelectric actuator is based on reorientation of the non-180??domains in the ferroelectric materials. In this study, a unimorph shape memory piezoelectric actuator with a soft lead zirconate titanate was fabricated. The fatigue and retention properties of this shape memory piezoelectric actuator were investigated. The fatigue behavior of the actuator in the early stages is considered to be closely related to the domain stabilization process. Continuous cycle fatigue tests revealed that the shape memory piezoelectric actuator continues to operate even after 106 cycles. Retention measurements revealed that the depoled state of the actuator was more stable than the poled state. The drift in the actuator displacement over one year was estimated to be less than 10% of the initial shape memory displacement.

The effect of endotoxin on fluidity and lipid composition of the erythrocyte membrane was studied in rats following the intraperitoneal administration of endotoxin (30 mg.kg(-1) body weight). Erythrocyte membrane fluidity measured with 16-stearic acid spin label (16-SAL) was significantly decreased in the endotoxin-treated rats as compared with control. A decrease of lysophosphatidylcholine in the membrane lipid was evident in the endotoxin-treated rats. The cholesterol to phospholipid molar ratios and other phospholipid fractions did not differ significantly in the two groups. The levels of plasma Beta-glucuronidase activity and lipoperoxide were significantly increased in the endotoxin-treated rats when compared to controls. There were significant correlations between the parameter of 16-SAL in erythrocytes and plasma Beta-glucuronidase activities or lipoperoxide from both endotoxin-treated and control groups, P0.005 or P0.02 respectively. In conclusion endotoxin decreased rat erythrocyte membrane fluidity in vivo. Since membrane fluidity is closely related to the vital functions of the membranes, the change described could be related to the abnormality of cell membrane functions in endotoxin shock state.

This paper examines the growth of InP epilayers on Si substrates that have GaAs intermediate layers. To improve InP crystalline quality, the GaAs intermediate layer thickness is optimized and four-thermal-cycle annealing is performed after GaAs and/or InP growth. The InP epilayers have a higher crystalline quality than InP epilayers grown directly on Si. When the InP epilayer thickness is 6{mu}m, the x-ray full width at half-maximum is 250 arcseconds and the etch pit density is 3 {times} 10{sup 7}cm{sup {minus} 2}.

A 1.55 μm multiple quantum well laser heteroepitaxially grown on Si substrate operates under the severe aging condition of the light output of 5 mW/facet at 50 °C. The laser has been operating for more than 7000 h. The threshold current and the slope efficiency of the laser on Si at 20 °C are 32 mA and 0.19 W/A, respectively. The maximum operation temperature is above 80 °C.

The electrical properties of a (100) InP surface were studied based on the fabrication process of a buried heterostructure (BH) laser diode (LD). The current–voltage (I–V) and capacitance–voltage (C–V) characteristics were measured for Schottky barriers on the surface at each step of the process—reactive ion etching (RIE) with a mixture of methane (CH4) or ethane (C2H6) and hydrogen (H2), oxygen plasma treatment, chemical etching, and annealing—under conditions which produce almost the same surface as that immediately before the BH regrowth. From the characteristics, it was found that CH4/H2 and C2H6/H2 RIEs caused the appearance of almost the same damage layers as a result of phosphorus desorption and hydrogen passivation in the near-surface region. Furthermore, it was found that only annealing can remove the hydrogen passivation. These results suggest that to obtain a high-quality regrowth interface it is essential to chemically etch the damage layers resulting from phosphorus desorption prior to BH reg...

This paper examines the growth of InP epilayers on Si substrates that have GaAs intermediate layers. To improve InP crystalline quality, the GaAs intermediate layer thickness is optimized and four-thermal-cycle annealing is performed after GaAs and/or InP growth. The InP epilayers have a higher crystalline quality than InP epilayers grown directly on Si. When the InP epilayer thickness is 6{mu}m, the x-ray full width at half-maximum is 250 arcseconds and the etch pit density is 3 {times} 10{sup 7}cm{sup {minus} 2}.

A total area conversion efficiency of 18.3% (one sun, AM0) was achieved with 10*10 mm/sup 2/ GaAs-on-Si cells by dislocation reduction in the cell active layers using in situ thermal cycles, a strained-layer superlattice, and a multilayered AlGaAs buffer. The efficiency is comparable to that of conventional homoepitaxial liquid-phase epitaxy cells. The radiation resistance of the GaAs-on-Si cells was confirmed by 1 MeV electron irradiation tests. >