Temperature and humidity dependence of the electrode polarization in intermediate-temperature fuel cells employing CsH2PO4/SiP2O7-based composite electrolytes

The polarization behaviors of platinum electrode were investigated with a single cell employing CsH₂PO₄/SiP₂O₇-based composite electrolyte. The electrochemical measurements were conducted in the temperature range of 180–240 °C under various humidity conditions. The cell performance was enhanced during several discharge cycles, and then the steady state was attained. The active triple phase boundary (TPB) appears to be spontaneously formed. The polarization behaviors for both anode and cathode were strongly affected by the electrolyte conductivity due to its humidity dependence. In accordance with this tendency, the maximum performance was achieved at 220 °C in 30% humidified condition whereas the deterioration was observed at 240 °C. Throughout the analysis, however, the performance limitation was mainly due to cathodic polarization at every condition. The cathodic overpotential showed a linear dependence against the log of current density at each temperature, which can be expressed as a Tafel equation. Then, the influence of steam concentration and temperature on the electrochemical kinetics was also discussed.     

Applied analysis and identification of ancient lacquer based on pyrolysis‐gas chromatography/mass spectrometry

Three lacquer samples taken from a “four‐eared” pottery container, which was designated an important National Cultural Property of Japan excavated in 16–17th century ruins of Kyoto City, were analyzed by pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS) and infrared (IR) spectroscopy to determine the source of the lacquer. It is an unexpected result that the lacquer in this pottery container is actually used by Melanorrhoea usitata. Alkylbenzene and alkenylbenzene as cleavage pieces of undecylbenzene (MW = 232 g/mol) and undecenylbenzene (MW = 230 g/mol), which are products of the pyrolysis of thitsiol, were detected in all three samples. Moreover, ω‐phenylalkylcatechols and ω‐phenylalkylphenols, which are the specific components of M. usitata, were also detected by Py‐GC/MS, suggesting that lacquer sap of M. usitata was used by the Japanese people in the 16–17th centuries. In addition, Japanese lacquer culture and the advantages of the Py‐GC/MS method for lacquer analysis are discussed in detail. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Nickel-aluminides/steel clad pipe fabricated by reactive centrifugal casting method from liquid aluminum and solid nickel

A novel method to produce an aluminide/steel clad pipe has been proposed. The method is based on a combination of the self-propagating high-temperature synthesis (SHS) reaction and centrifugal casting, and is named the reactive centrifugal casting method. Nickel powder was placed on a rotating steel pipe, and aluminum liquid was poured into the steel pipe. The aluminum liquid and nickel powder exothermically reacted and produced a composite layer consisting of nickel aluminides on the inner surface of the steel pipe. The heat generated by the exothermic reaction melted the inner surface of the steel pipe and bonded the composite layer to the steel. It was found that increases in centrifugal force generated by rotating the steel pipe, the pouring temperature of the aluminum, and the preheating temperature of the nickel and steel remarkably promote the reaction between nickel and aluminum. In addition, the amounts of initial aluminum and nickel were found to play an important role in controlling the microstructure of the composite layer. Thus, the aluminide/steel clad pipe can be successfully fabricated by the proposed reactive centrifugal casting method.     

A Genotoxic Stress-Responsive miRNA,miR-574-3p,Delays Cell Growth by Suppressing the Enhancer of Rudimentary Homolog Gene in Vitro

MicroRNA (miRNA) is a type of non-coding RNA that regulates the expression of its target genes by interacting with the complementary sequence of the target mRNA molecules. Recent evidence has shown that genotoxic stress induces miRNA expression, but the target genes involved and role in cellular responses remain unclear. We examined the role of miRNA in the cellular response to X-ray irradiation by studying the expression profiles of radio-responsive miRNAs and their target genes in cultured human cell lines. We found that expression of miR-574-3p was induced in the lung cancer cell line A549 by X-ray irradiation. Overexpression of miR-574-3p caused delayed growth in A549 cells. A predicted target site was detected in the 3′-untranslated region of the enhancer of the rudimentary homolog (ERH) gene, and transfected cells showed an interaction between the luciferase reporter containing the target sequences and miR-574-3p. Overexpression of miR-574-3p suppressed ERH protein production and delayed cell growth. This delay was confirmed by knockdown of ERH expression. Our study suggests that miR-574-3p may contribute to the regulation of the cell cycle in response to X-ray irradiation via suppression of ERH protein production.     

Numerical computation for solving algebraic Riccati equations of weakly coupled systems

In this paper, an algorithm for solving the algebraic Riccati equation (ARE) that has an indefinite sign quadratic term related to weakly coupled large‐scale systems is investigated. A novel contribution is that a new iterative algorithm is derived by combining Newton's method and the fixed point algorithm. As a result, for sufficiently small ε, we can obtain an ARE solution with a quadratic convergence rate. Moreover, it is possible to calculate the ARE solution for the same dimension of each subsystem. As another important feature, an algorithm for solving the filter ARE is also discussed. Finally, in order to demonstrate the efficiency of the proposed algorithm, a numerical example is given. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(1): 39–48, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20370     

3D Object Recognition in Cluttered Environments by Segment-Based Stereo Vision

We propose a new method for 3D object recognition which uses segment-based stereo vision. An object is identified in a cluttered environment and its position and orientation (6 dof) are determined accurately enabling a robot to pick up the object and manipulate it. The object can be of any shape (planar figures, polyhedra, free-form objects) and partially occluded by other objects. Segment-based stereo vision is employed for 3D sensing. Both CAD-based and sensor-based object modeling subsystems are available. Matching is performed by calculating candidates for the object position and orientation using local features, verifying each candidate, and improving the accuracy of the position and orientation by an iteration method. Several experimental results are presented to demonstrate the usefulness of the proposed method.     

A high efficiency thin film silicon solar cell and module

A photoelectric conversion efficiency of over 10% has been achieved in thin-film microcrystalline silicon solar cells which consist of a 2 μm thick layer of polycrystalline silicon. It was found that an adequate current can be extracted even from a thin film due to the very effective light trapping effect of silicon with a low absorption coefficient. As a result, this technology may eventually lead to the development of low-cost solar cells. Also, an initial aperture efficiency as high as 13.5% has been achieved with a large area (91 cm × 45 cm) tandem solar cell module of microcrystalline silicon and amorphous silicon (thin film Si hybrid solar cell). An even greater initial efficiency of 14.7% has been achieved in devices with a small size (area of 1 cm²), and further increases of efficiency can be expected.     

降低R32压缩机排气温度的方法

作为下一代制冷剂替代物,R32 由于其GWP值较低、热工性能好,正在受到瞩目.但是正因为其容积制冷量大、热工效率高,R32 与其他制冷剂相比具有压缩机排气温度高的特点.解决这个问题成为一项将 R32 实际应用到环境负荷小、高能效而且成本比较低的空调系统,并推广到世界市场的重要技术课题.本文将阐述利用膨胀阀控制压缩机吸气干度,同时使用 R32 专用的润滑油来降低排气温度,以解决这个问题的方法.     

Mechanical Properties,Morphologies, and Microstructures of Novel Electrospun Metallized Nanofibers

We report that the metal‐deposited single nanofibers can be successfully prepared by electrospinning and metallization. The tensile strength of the metal‐deposited single nanofibers as well as various non‐metallized polymeric nanofibers was investigated by recently developed tensile test machine. The tensile strength of 50 nm metal‐deposited single nanofibers was dramatically improved, which was much higher than that of pure polymer single nanofiber. The result is attributed to the formation of metallic hard‐coating layers onto the surface of single nanofibers. The tensile strength of the metal‐deposited single nanofibers was also depended on the types of metals (for instance, Cu, Ni, Sn, and Al) used for metallization. In addition, we investigated various annealing conditions, such as annealing temperature and time, and composition ratio of two metals (Cu and Ni), in order to find out optimum annealing process for the formation of metal alloy nanofibers. The characterization of the metallized nanofibers was conducted by field emission scanning electron microscope (FE‐SEM) and X‐ray diffraction (XRD).     

Preparation of adsorbent for phosphate recovery from aqueous solutions based on condensed tannin gel

We have synthesized an iron-loaded tannin gel as an adsorbent for phosphate recovery in aqueous solutions. The use of the tannin gel prepared from condensed tannin, which is a ubiquitous and inexpensive natural polymer, is not only cost effective and environment-friendly, but interesting because the phosphate-adsorbed gel can be expected to use directly as a fertilizer. The amount of iron loaded into the tannin gel oxidized by nitric acid was much larger than that into the non-oxidized tannin gel. This increase in the amount of the loaded iron resulted in the significant increase in the adsorption amount of phosphate onto the gel. Mössbauer spectroscopy indicated that the morphology of iron in the gel is a mono-type complex, which is formed as a result of the reaction between Fe(III) and the oxidized tannin gel with carbonyl groups. The iron-loaded tannin gel showed the adsorption selectivity for phosphate over other anions and the pH independence of phosphate adsorption in the wide range of initial pH 3-12. The phosphate adsorption isotherm for the iron-loaded tannin gel followed the Freundlich equation with constants of K_F = 2.66 and 1/n = 0.31, rather than the Langmuir equation. The adsorption amount of phosphate on iron weight basis for the iron-loaded tannin gel is 31.3 mg-P/g-Fe, which indicates that iron in the gel was efficiently used for the phosphate adsorption compared with other phosphate adsorbents, such as iron hydroxides.