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101.
Novel system of electro-catalysts was developed for methanol oxidation reaction (MOR) in direct methanol fuel cells. Mixture of platinum tetraammine complex with cobalt quinolyldiamine complex with various mixing ratio was supported on graphite powder, and heat treated at 400-1000 °C in argon atmosphere. Powder thus obtained was put on a graphite disk electrode, and tested for electrochemical MOR in acid media. Although the cobalt complex itself showed almost no catalytic ability for MOR, it enhanced the activity of Pt more than several 10-fold when it was mixed with Pt. MOR performance was best exploited at about equal mixing ratio of platinum and cobalt complexes. Compared with platinum-ruthenium alloy catalysts, the new catalysts exhibited promising catalytic ability. The present investigation revealed good potentiality of organic complex catalysts in combination with metal catalysts for MOR, which opens the way to synthesize and develop a new class of electro-catalysts of low cost through wide range of molecular designing. 相似文献
102.
The mechanical properties of styrene‐butadiene rubber (SBR) vulcanizates prepared using various plasticizers including liquid polybutadiene and styrene‐butadiene copolymers were investigated. The effect of the liquid polymers as the plasticizers on the mechanical properties of the polymers, such as the hardness, tensile storage modulus, tanδ, and the modulus at 100% elongation values, were determined before and after the thermal aging. As a result, it was revealed that the use of these liquid polymers gave less amount of change in the measurement values for the mechanical properties during the aging. The crosslinking density and the amount of free polymers were also determined on the basis of the swelling and extraction data, respectively, using several organic solvents. These results support the fact that the added liquid polymers are fixed to the SBR networks. We revealed the superiority of the liquid styrene‐butadiene copolymers as the plasticizer, which provides sufficient mechanical properties after vulcanization and the excellent maintenance of the properties during the thermal aging process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
103.
Novel chitosan‐based materials with a higher fatty acid glycidyl as the chemically modified agent were synthesized and the adsorption ability of the resulting polymers has been evaluated for typical anionic and cationic dyes. The successful modification was confirmed by the infrared spectroscopic measurements. As the degree of substitution was decreased, the adsorption ability of the chemically modified chitosans for anionic dyes at the higher dye concentration was increased, and the modified chitosans with a lower degree of substitution showed a higher adsorption ability than that of an activated carbon at the higher dye concentration. For cationic dyes, the chemically modified chitosan showed a good adsorption power, especially when the adsorption power was evaluated by the flow methods. The improved adsorption ability of a chemically modified chitosan material was also confirmed by comparing it with that of a crosslinked chitosan material. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2423–2428, 2005 相似文献
104.
The adsorption of metal ions (Mo6+, Cu2+, Fe2+, and Fe3+) was examined on chemically modified chitosans with a higher fatty acid glycidyl (CGCs), and the adsorption of Cu2+ was examined on ethylenediamine tetraacetic acid dianhydride modified CGCs (EDTA‐CGCs) synthesized by the reaction of the CGCs with ethylenediamine tetraacetic acid dianhydride. The adsorption of phosphate ions onto the resulting substrate/metal‐ion complex was measured. Mo6+ depicted remarkable adsorption toward the CGCs, although all the Mo6+ was desorbed under the adsorption conditions of the phosphate ions. The other metal ions were adsorbed to some extent on CGCs by chelating to the amino group in the substrate, except for CGC‐1, which had the highest degree of substitution (83.9%). Considerable amounts of Fe2+ were adsorbed onto CGCs; however, only a limited number of phosphate ions was adsorbed onto the substrate/metal‐ion complex. As a result, the following adsorbent/metal‐ion complexes gave higher adsorption ability toward phosphate ions: CGC‐4/Cu2+, CGC‐4/Fe3+, and EDTA‐CGC‐3/Fe3+. Where, CGC‐3 is a chemically modified chitosan with the degree of substitution of 26.5 percentage, and CGC‐4 is one with the degree of substitution of 16.0 percentage. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
105.
Keisuke Yoshida Kenji Mishiro Yoshihiro Ueda Takashi Shigeta Takumi Furuta Takeo Kawabata 《Advanced Synthesis u0026amp; Catalysis》2012,354(17):3291-3298
A highly geometry‐selective organocatalytic acylation of tri‐ and tetra‐substituted 2‐alkylidene‐1,3‐propanediols has been developed. The highly E‐selective acylation of various tetrasubstituted 2‐alkylidene‐1,3‐propanediols was achieved in 96 to >99% selectivity for the first time by a non‐enzymatic protocol. 相似文献
106.
We present a technique to determine the transition shape in digital magnetic recording. The method involves analyzing both temporal and spectral transition noise measurements. This combined method simultaneously determines the transition parameter and the cross-track correlation width along with the transition shape. 相似文献
107.
108.
109.
Takeo Uga 《Nuclear Engineering and Design》1974,26(2):326-335
A new test specimen for thermal-stress ratchetting is proposed and tested for standard AISI-304 stainless steel. Its purpose is to avoid the drawbacks of a tubular specimen. It is a special plate-shaped specimen with two symmetrical, straight air gaps in the center portion and load chucks at the ends. Since three surfaces out of four on the side bars are enveloped by sheathed trace heaters, the middle bar becomes a cold element and the rest side bars hot elements during thermal loading. Experiments on thermal-stress ratchetting are performed with this specimen. Interesting incremental strain growth behaviour of the specimen subjected to cyclic thermal stresses under a steady primary load is obtained with regard to an actual strain-hardening material. It was confirmed that incremental strain growth decreased with increase in the cumulative strain growth. There is expected to be an asymptotic cumulative strain growth for any test condition. It is also found that the tendency for theoretical strain growth is fairly similar to that found experimentally. However, the experimental data are considerably greater than the theoretical data. This can be explained qualitatively by a decrease in both yield strength and Young's modulus at high temperature for the hot elements. 相似文献
110.
Takeo Oku Atsushi Nishiwaki Ichihito Narita 《Science and Technology of Advanced Materials》2004,5(5-6):635
Boron nitride (BN) nanocage clusters of B12N12 were synthesized, and detected by laser desorption time-of-flight mass spectrometry. The B12N12 clusters consisted of 4- and 6-membered BN rings satisfying the isolated tetragonal rule, which was optimized by molecular orbital calculations. The electronic structure showed a bandgap energy of 5.1 eV, which is a little smaller than that of B36N36 cluster. 相似文献