Application of conventional activated carbon loaded with dispersed Pt to PEFC catalyst layer

Improvement of the polymer electrolyte fuel cell (PEFC) requires development of highly active electrodes of low cost to facilitate its widespread use. In the present study, the possibility of applying conventional activated carbon particles loaded with Pt to the electrode catalyst layer was tested because the particles were promising in dispersion of Pt and preparation cost. The catalyst layer was formed from the particles and Nafion® and was supported as a thin film on a rotating glassy carbon disk electrode (GC RDE). Activity for oxygen reduction was evaluated by the hydrodynamic voltammetry in perchloric acid to give a current free of the influence of mass transfer in the solution. Compared with a conventional catalyst layer formed from carbon black loaded with Pt, the new catalyst layer exhibited a significant, approximately 6-fold increase in current in the high potential region corresponding to a 100 mV increase in electrode potential. Activity, however, was retarded in the low potential region. This disadvantage was overcome by mixing a conductive agent into the layer and covering it with another layer containing carbon black loaded with Pt. This double catalyst layer exhibited increased activity across all potential regions, indicating the availability of the activated carbon in the electrodes.     

Perspectives on the role of the lateral pterygoid muscle and the sphenomandibular ligament in temporomandibular joint function

This is a phase II study to evaluate the efficacy and toxicity of short-course carboplatin in advanced-stage nasopharyngeal carcinoma (NPC). Thirty-three previously untreated stage III-IV NPC patients were studied. Carboplatin was given as a rapid intravenous injection every 3 weeks. The dose of carboplatin was calculated according to the individual patient's creatinine clearance and desired platelet nadir of 75,000/microliter according to the Egorin formula. Response and toxicity were evaluated. Thirty-two patients were evaluated for response. The median age was 54 years, range 30-70 years. Twenty-four patients had local regional disease and 8 patients had metastatic disease. The median dose of carboplatin given was 415 mg/m2 (range 91-791 mg/m2). Fourteen (44%) patients had a partial response with a 95% confidence interval of 26-62%. Fifteen (47%) patients had stable disease and 3 (9%) progressive disease. The overall median survival rate was not reached at 43 months. Overall toxicity was tolerable. Grade III-IV myelosuppression occurred in 4 (12%) patients. There were no other major toxicity- or treatment-related deaths. We conclude that carboplatin has a significant anticancer effect in advanced NPC. Thus carboplatin combination chemotherapy for the treatment of NPC is worthy of future clinical investigations.     

Low-Thermal-Expansion Properties of Sodium- and Lithium-Substituted Cubic Cesium Leucite Compounds

Cubic cesium leucite-based compounds, namely cesium leucites, cesium sodium leucites, and cesium lithium leucites, were synthesized using a multistep solid-state reaction method. The thermal expansion properties, in the temperature range of 298-1273 K, for the synthesized cubic cesium leucite-based compounds were examined using high-temperature powder X-ray diffractometry data. The thermal expansions of the cubic cesium leucite-based compounds were found to vary with the chemical composition. For instance, the thermal expansions of Cs_0.7Na_0.2Al_0.9Si_2.1O₆ and Cs_0.7Li_0.2Al_0.9Si_2.1O₆ were 0.14% at 1273 K and 0.081% at 1073 K, values lower than those of Cs_0.9Al_0.9Si_2.1O₆, which were 0.16% at 1073 K and 0.2% at 1273 K. The results showed that the thermal expansions of the cubic cesium leucite-based compounds changed with ionic substitution at the Cs⁺ sites because of ionic size differences between Cs⁺ and the Na⁺ or Li⁺ substitutional ions.     

Phase equilibria in Fe-Cu-X (X: Co, Cr, Si, V) ternary systems

Phase equilibria on the Fe-Cu side in the Fe-Cu-X (X: Co, Cr, Si, V) system were experimentally determined over the temperature range of 1073–1273 K. Based on the present results and previous works, the thermodynamic assessments of the phase equilibria in the Fe-Cu-X system were evaluated using the Calculation of Phase Diagram (CALPHAD) method. The Gibbs energies (G) of the bcc, fcc, and liquid phases are described by the subregular solution model, and a set of thermodynamic parameters enable us to calculate various isothermal and vertical sections and the miscibility gaps of the solid and liquid phases.     

Frictional Anisotropy of Oblique Nanocolumn Arrays Grown by Glancing Angle Deposition

Frictional anisotropy of oblique Ti nanocolumns grown by glancing angle deposition (GLAD) was investigated by ramp-scratch experiments in forward (in the direction of the column tilt) and reverse (against the column tilt) directions using rectangular and conical loading tips. Strong anisotropy in friction was generally observed, wherein the resistance or friction coefficient in reverse scratching was higher than that in forward scratching, and the reverse resistance was sensitive to the tip shape. In forward scratching, the nanocolumns bend with the column tilt direction, designated as the W-mode deformation. On the other hand, in reverse scratching, the nanocolumns deflect against the column tilt in high normal force, designated as the A-mode deformation. The deformation mode changes from the W-mode to the A-mode as the normal force increases in reverse scratching. The mechanism of the frictional anisotropy was discussed on the basis of a simple deformation model of column by finite element method. The anisotropy can be explained by the difference in the deformation mode. That is, compressive deformation in the longitudinal direction and large deflection against the column tilt induce higher friction resistance in reverse scratching than in forward scratching brought about by compliant bending deformation with the column tilt.     

Novel screening system for protein-protein interactions by bimolecular fluorescence complementation in Saccharomyces cerevisiae

For high-throughput screening of protein-protein interactions, we have developed a novel yeast screening system using Bimolecular fluorescence complementation (BiFC). Two yeast plasmids, in which genes of heterodimerized peptides LZA and LZB were each fused with those of non-fluorescent half fragments of Kusabira-Green mutant (mKG2), were transformed into a- and α-type yeast, respectively. Mating of them gave a library, which was screened by following green fluorescence resulted from LZA-LZB interaction. The method showed potential ability to detect the positive clones from a model library, in which green-fluorescent and non-fluorescent yeast was mixed in a ratio of 1:675.     

Geotechnical Aspects of the Sumatra Earthquake of September 30, 2009, Indonesia

This paper reports and discusses the results of a field survey conducted by a joint scientific group from Japan and Indonesia to assess the geotechnical aspects of the Sumatra earthquake (M_w=7.6) of September 30, 2009. The studied area included the Padang and Pariaman cities, where a number of buildings collapsed as a result of strong shaking, and a mountainous part of the Pariaman district, a place where massive landslides buried several villages, claiming more than 400 human lives. The main objective of the survey was to investigate the causes and mechanisms of catastrophic landslides; however, other geotechnical problems such as lateral spread and liquefaction were also addressed. Field observations indicated that the catastrophic landslides occurred on relatively gentle slopes, then mobilized into debris flows, and traveled several hundred meters from their points of origin. The failure surfaces developed along the boundary of highly weathered pumice tuff with more intact and less weathered bedrock. Data from a portable cone penetration test showed that the sliding material was rather weak, having SPT N-values in the range of 5-10. The results of the field survey suggested that the main cause of slope instability was high pore-water pressures that generated in the soil mass during the earthquake.     

Fracture observation of polycrystalline diamond film under indentation test

Indentation tests using Vicker's pyramidal and Rockwell spherical diamond indenters were performed for polycrystalline diamond film deposited by chemical vapour deposition (CVD) on SiC substrate. Two types of film with different crystal sizes were tested. One is a film with grain size of 5 to 10 μm, denoted as MCD. Another one is a film with grain size of less than 100 nm, denoted as NCD.In the Vicker's test, we observed clear indentation and radial cracks for the NCD film, suggesting that micro-cracks tend to generate along the weak grain boundaries. Young's modulus, estimated from unloading curve of both films, agrees well with the value (928 GPa) estimated by the laser ultrasonic method.Rockwell indentation test predicts that the adhesion of the NCD film is lower than that of the MCD, and compressive residual stress of the MCD is much larger than that of the NCD. We observed ring cracks and detected acoustic emission (AE) signals from the ring cracks.     

Discharge behaviour of electrodeposited PbO2 and Pb electrodes

The discharge behaviour of electrodeposited lead dioxide and lead electrodes was investigated under various conditions; the surfaces of the discharged electrodes were observed with a scanning electron microscope. Both the positive and negative electrodes were passivated by a covering of deposited lead sulphate crystals. The amount of lead sulphate required for passivation depended on the size of the crystals.