Synthesis of β-MoO3 whiskers by the thermal evaporation method with flowing oxygen gas

β-MoO₃ is a monoclinic phase of MoO₃; it has been shown to be a promising material that can replace α-MoO₃ in chemical, optical, electronic, and electrochromic applications. However, the difficulty in synthesizing β-MoO₃ with a one-dimensional (1D) morphology has limited its use in applications requiring a large specific surface area. In the present work, β-MoO₃ whiskers were prepared by thermally evaporating α-MoO₃ powder in a tube furnace at temperatures (T_f) from 750 to 1000°C and under flowing O₂ gas. The collected samples were identified as mainly β-MoO₃ by X-ray diffraction measurements, and the highest purity β-MoO₃ was obtained at T_f = 1000°C. Scanning and transmission electron microscopy observations showed that whiskers with a width of 10 nm were successfully synthesized by this method. The whiskers were confirmed to be β-MoO₃ via lattice image analysis. Measurements of the temperature distribution in the tube furnace and comparisons with the Mo–O phase diagram led to the conclusion that the whiskers formed via a vapor–solid route. Prepared β-MoO₃ whiskers were compared with α-MoO₃ powder via the X-ray photoelectron spectroscopy characterization method. By elucidating the β-MoO₃ whisker synthesis mechanism, this research provides guidance for the large-scale production of β-MoO₃ whiskers.     

Two-Dimensional Simulation of Cake Growth in Slip Casting

A two-dimensional computer simulation of cake growth was studied for the slip casting of alumina with a gypsum mold. Based on the Adcock and McDowall model, the method of finite differences was applied to the simulation, and numerical calculations were performed for the cake growth on the inside wall of a rectangular, box-type mold by using the cake-growth controlling parameters that were obtained experimentally. Good agreement was observed between the experimental and calculated cake growth in the vicinity of the boundary between the gypsum mold and the silicon rubber and at the rectangular corner of the gypsum mold. The present simulation method is expected to be useful for estimating cake growth on molds with complicated shapes in slip casting.     

Laser Beam Machining of Porous Woodceramics

Laser beam machining was tested as a practical method for machining porous woodceramics (WCS). A black carbonized layer is generally formed on the processed surface when woody materials are processed with laser beam machining. This problem does not occur on the WCS because they are burned. The processed surface temperature during laser beam machining can be estimated from the relationship between the burning temperature and C and O₂ component concentrations. Burning (scorching) on the processed surface decreases slightly as the feed speed of the workpiece increases. WCS are more easily processed with laser machining after being burned, using pulse oscillation to reduce the thermal influence.     

Optimization of preparation conditions and improvement of stability of Cu/ZnO-based multicomponent catalysts for methanol synthesis from CO2 and H2

The operation conditions for preparing a Cu/ZnO-based multicomponent catalyst by a coprecipitation method were optimized. The temperature during coprecipitation should be less than 313 K, and the removal of Na from the catalyst by washing the precipitates is most important. Furthermore, a small amount of silica added to the catalyst greatly improved its long-term stability in methanol synthesis from CO₂ and H₂.     

Public perception on hydrogen infrastructure in Japan: Influence of rollout of commercial fuel cell vehicles

A public survey was conducted in March 2015 in Japan asking public awareness, knowledge, perception and acceptance regarding hydrogen, hydrogen infrastructure and fuel cell vehicle. Changes in answers were found by comparing results of current survey to those of the two previous surveys that were conducted six and seven years ago. We found a large increase in the awareness and relatively a small improvement on knowledge on hydrogen energy, hydrogen infrastructure and fuel cell vehicle from the previous surveys. In contrast we did not find much changes in perception of risk and benefit on hydrogen society and hydrogen station and public acceptance of hydrogen infrastructure. Through the regression analyses we found the small influence of time background as well as the influence of risk and benefit perception of hydrogen infrastructure on the acceptance. In conclusion, we find people have become a little more positive about hydrogen infrastructure in the baseline but more cautious about the risk and benefits. This can be interpreted as a change in the quality of perception and acceptance, that is, the favorable prejudice to hydrogen energy and fuel cell technologies has changed towards a slightly more rational support.     

One‐step Synthesis of Water‐soluble Fullerenols Bearing Nitrogen‐containing Substituents

We found a facile one‐step synthetic method for water‐soluble fullerenols bearing 8–16 nitrogen‐containing substituents as well as more than 16 hydroxyl groups from commercially available C₆₀ as a starting material. The water solubility of one of the products showed the same as the highest one reported (>200 mg/mL). Other fullerenols bearing hydrogen or diethylamino group on the same fullerene cage were also synthesized by the modified method using hydrogen peroxide as a simple hydroxylation reagent.     

Thalidomide increases both REM and stage 3-4 sleep in human adults: a preliminary study

OBJECTIVE: Methotrexate has been documented to accumulate in pleural effusions and ascitic fluid, resulting in severe local and systemic toxicity. In the following case report, we publish results of intraoperative measurements of methotrexate levels in serum and an ovarian cyst and attempt to determine if ovarian cysts similarly act as a depot for methotrexate. METHODS: After determining intraoperative measurements of serum and ovarian cystic levels of methotrexate, we compared demonstrated pharmacokinetics to those expected by using pharmacokinetic systems analysis software. RESULTS: Intraoperative measurement of methotrexate levels on day 3 of a 5-day methotrexate regimen revealed a serum methotrexate concentration of 1.6 x 10(-7) M and a concentration of 3.1 x 10(-7) M within the 166.4 ml ovarian cyst. CONCLUSIONS: The measured levels demonstrate that methotrexate is sequestered within an ovarian cyst resulting in higher local drug levels. Our pharmacokinetic analysis suggests that methotrexate doses less than 100 mg/m2 can be safely administered to patients with small ovarian cysts. However, computed simulations support the possibility of local and systemic toxicity arising from large ovarian cysts when using high doses of methotrexate.     

Parameters influencing breakdown characteristics of vacuum gapsduring spark conditioning

Experiments have been made to identify the key parameters in the increase of the breakdown strength of a vacuum gap through repetitive breakdowns. The current-voltage waveforms were observed, the residual stress in electrodes was measured, and the chemical composition of the electrode surfaces and the energy of the valence-band electrons were analyzed. These experiments revealed that prebreakdown currents (field emission currents) were sometimes observed and sometimes not. The residual stress before and after 500 breakdowns changed significantly. X-ray photoelectron spectroscopy analysis before and after 500 breakdowns showed that the spectral lines of oxygen and carbon due to contaminants on the electrode surface were completely removed and the copper ones appeared clearly after 500 breakdowns. The valence-band electron energy spectrum of the anode after 500 breakdowns shifted towards the lower binding energy to almost coincide with the theoretical spectrum, while the energy spectrum for the cathode shifted towards sometimes higher and sometimes lower binding energy     

Saturation and Polarization Characteristics of 1.56 μm Optical Probe Pulses in a LTG-GaAs Photoconductive Antenna Terahertz Detector

The characteristics of low temperature-grown GaAs photoconductive antenna (PCA) terahertz detectors probed by 1.56 μm laser pulses are investigated. The influence of TM and TE polarized probe, as well as the saturation characteristics are studied for 2 μm- and 5 μm-gap PCA’s. Different polarization characteristics at low probe powers and at the saturation regimes were observed. Results are explained in terms of the polarization-dependent photocarrier distribution at the PCA gap arising from tight focusing. This work also demonstrates using a 1.56 μm probe for a GaAs PCA to achieve ~60 dB SNR; matching its performance characteristics for above-bandgap probes.