Intermediate temperature solid oxide fuel cells using LaGaO3 based oxide film deposited by PLD method

Dense La_0.9Sr_0.1Ga_0.8Mg_0.2O_3-δ (LSGM, 5 μm in thickness)/Ce_0.8Sm_0.2O_2-δ (SDC, 400 nm in thickness) bilayer films were deposited on a dense NiO (Fe₃O₄)-SDC anode substrate by a pulsed laser deposition (PLD) method. After in-situ reduction, the substrate turned to be porous and it can be used as a porous anode substrate. The power density was strongly affected by the oxide ion conductor combined with LSGM and it was found that SDC is the most useful for achieving the high power density. Preparation of Sm_0.5Sr_0.5CoO₃ cathode film by PLD method is also studied for decreasing the contact resistance of cathode. Preparation of SSC film by PLD is effective for decreasing cathodic overpotential and 400 nm thick film is the most effective for achieving the high power density. At 773 K, the maximum power density of the cell becomes higher than 500 mW/cm².     

Electrostatic Cleaning System for Removing Lunar Dust Adhering to Space Suits

Removing lunar dust adhering to astronaut space suits is critically important for long-term lunar exploration. We are developing an automatic cleaning system that uses electrostatic force. It employs an alternating electrostatic field that forms a barrier on the surface of fabrics. In this study, we applied single-phase rectangular voltage to parallel wire electrodes stitched into the insulating fabric of space suits. By applying mechanical vibration and operating the system in a vacuum, we realized high performance: the cleaning rate exceeded 80%. Flicking out particles smaller than 10?μm in diameter that were trapped between fibers was difficult, but this system can perform preliminary space suit cleaning and save precious time for astronauts on the moon.     

Intravenous Administration of Cilostazol Nanoparticles Ameliorates Acute Ischemic Stroke in a Cerebral Ischemia/Reperfusion-Induced Injury Model

It was reported that cilostazol (CLZ) suppressed disruption of the microvasculature in ischemic areas. In this study, we have designed novel injection formulations containing CLZ nanoparticles using 0.5% methylcellulose, 0.2% docusate sodium salt, and mill methods (CLZ_nano dispersion; particle size 81 ± 59 nm, mean ± S.D.), and investigated their toxicity and usefulness in a cerebral ischemia/reperfusion-induced injury model (MCAO/reperfusion mice). The pharmacokinetics of injections of CLZ_nano dispersions is similar to that of CLZ solutions prepared with 2-hydroxypropyl-β-cyclodextrin, and no changes in the rate of hemolysis of rabbit red blood cells, a model of cell injury, were observed with CLZ_nano dispersions. In addition, the intravenous injection of 0.6 mg/kg CLZ_nano dispersions does not affect the blood pressure and blood flow, and the 0.6 mg/kg CLZ_nano dispersions ameliorate neurological deficits and ischemic stroke in MCAO/reperfusion mice. It is possible that the CLZ_nano dispersions will provide effective therapy for ischemic stroke patients, and that injection preparations of lipophilic drugs containing drug nanoparticles expand their therapeutic usage.     

Output current ripple reduction of LED driver using ceramic‐capacitor‐input circuit and buck‐boost converter

This article proposes an LED driver that consists of a ceramic‐capacitor‐input rectifier and a buck‐boost converter. The LED driver has an advantage of long life because it does not contain any electrolytic capacitors. However, the issue with electrolytic capacitor‐less LED driver is that the ripple of the smoothed voltage becomes large due to insufficient capacitance of the smoothing capacitor. The proposed method, which uses the discontinuous current mode of a buck‐boost converter, reduces the output current ripple under such conditions. Experimental results using a 5.7 W LED driver prototype demonstrate that the proposed method reduces the output current ripple and that the percent flicker becomes 4.4%, which is smaller than the recommended upper limit of 8%.     

Improved performance of mixed single layer top-emission organic light emitting devices using capping layer

The performance of top-emission organic light emitting devices (TEOLEDs) can be improved by using a thin capping layer on top of the semitransparent metal electrode. We investigated the emission properties of inverted mixed single layer TEOLEDs with the same device structure but different capping materials. The thickness of capping layer was optimized by calculation. The power efficiency of device was 2.5 times enhanced when 45 nm TPD capping layer was added. The enhancement is not simply dependent on the transmittance and reflectance of the top contact, but also on other complex phenomena such as the interference effects in the device. The results of properties and dependence of EL spectra on viewing angle for all devices indicated that the large enhancement factor may be related to the complex interference phenomenon in our mixed single layer devices due to the emitter center and recombination region is different from conventional heterojunction devices.     

Measurements of strain and humidity within massive concrete cylinders related to the formation of ASR surface cracks

This study aims at proving the validity of a notion that the formation of non-expansive near-surface layer is responsible for surface cracking in ASR-affected concretes by a laboratory experiment. Relationship between the progress rate of the front of non-expansive layer toward inner portions and the formation of the first surface cracks was scrutinized by measuring relative humidity (R.H.) values and strains within a massive concrete cylinder (?450 mm × 900 mm) with reactive aggregates under a dry environment. It was presumed from the measurements that a non-expansive layer of about 40 mm had been formed at the first cracking. Thereafter, the environmental humidity was raised to > 95% R.H. Pursuit of the growth of surface cracks and subsequent measurements of strains and R.H. values within the concrete cylinder under the moist environment suggested that the re-saturation continuously gave rise to the generation of tensile stresses in near-surface regions leading to active extension of surface cracks.     

GPU-acceleration for Moving Particle Semi-Implicit method

The MPS (Moving Particle Semi-implicit) method has been proven useful in computation free-surface hydrodynamic flows. Despite its applicability, one of its drawbacks in practical application is the high computational load. On the other hand, Graphics Processing Unit (GPU), which was originally developed for acceleration of computer graphics, now provides unprecedented capability for scientific computations.The main objective of this study is to develop a GPU-accelerated MPS code using CUDA (Compute Unified Device Architecture) language. Several techniques have been shown to optimize calculations in CUDA. In order to promote the acceleration by GPU, particular attentions are given to both the search of neighboring particles and the iterative solution of simultaneous linear equations in the Poisson Pressure Equation.In this paper, 2-dimensional calculations of elliptical drop evolution and dam break flow have been carried out by the GPU-accelerated MPS method, and the accuracy and performance of GPU-based code are investigated by comparing the results with those by CPU. It is shown that results of GPU-based calculations can be obtained much faster with the same reliability as the CPU-based ones.     

Dynamics in Linear Cournot Duopolies with Two Time Delays

Linear differential duopolies are constructed with continuous time scales, constant coefficients and two types of information delays: fixed and continuously distributed time delays. System dynamics are considered with delays in the diagonal terms. By analyzing the associated characteristic equations, it is found that the stability is lost when the lengths of delays cross some critical values. Then it is shown that the destabilizing effect caused by the fixed delays is stronger than the destabilizing effect of the distributed delays having exponentially-declining weighting function. It is further demonstrated that the strength of the destabilizing effect is reversed if the distributed delay has a bell-shaped weighting function.