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61.
Oxidation of SiC compositionally graded (SCGed) graphite coated with HfO2 derived from HfCl4 by a sol–gel process was performed at 1500° and 1600°C in a flowing gas mixture of Ar and O2 (80/20 kPa). SCGed graphite was produced by reaction of graphite with either molten Si or SiO gas at 1450°C. The sol–gel-derived HfO2 precursor was deposited on SCGed graphite by a dip-coating method. Isothermal and cyclic oxidation of uncoated- and HfO2 -coated SCGed graphite was studied by monitoring overall weight change using an electro-microbalance. Scanning electron microscopy with energy-dispersive X-ray analysis was used to observe the surfaces and cross-sections of the oxidized HfO2 -coated SCGed graphite. The formation of HfSiO4 was confirmed on the outer layer of the oxidized sample, beneath which a thin silica layer was formed. The improved oxidation resistance of SCGed graphite by coating with HfO2 is discussed on the basis of the formation of these two layers. 相似文献
62.
Abnormalities in the Metabolism of Fatty Acids and Triacylglycerols in the Liver of the Goto-Kakizaki Rat: A Model for Non-Obese Type 2 Diabetes 下载免费PDF全文
63.
Detecting when the process has changed is a classical problem in sequential analysis and is an important practical issue in statistical process control. This article is concerned about the binomial cumulative sum (CUSUM) control chart, which is extensively applied to industrial process control, health care, public health surveillance, and other fields. For the binomial CUSUM, a maximum likelihood estimator has been proposed to estimate the change point. In our article, following a decision theoretic approach, we develop a new estimator that aims to improve the existing methods. For interval estimation, we propose a parametric bootstrap procedure to construct the confidence set of the change point. We compare our proposed method with the maximum likelihood estimator and Page's last zero estimator in terms of mean squared error by simulations. We find that the proposed method gives more unbiased and robust results than the existing procedures under various parameter designs. We analyze jewelry manufacturing data for illustration. 相似文献
64.
Inside Cover: Onocerin Biosynthesis Requires Two Highly Dedicated Triterpene Cyclases in a Fern Lycopodium clavatum (ChemBioChem 4/2016) 下载免费PDF全文
65.
A heat-induced O/W emulsion gel that undergoes a phase transition from sol to gel on heating was formed from the addition of aqueous HCl to a toluene solution of a long-chain amidoamine derivative (C18AA). The heat induced O/W emulsions are highly sensitive to temperature, and the sol-gel transition temperature could be simply controlled by adjusting the C18AA concentration. Interestingly, the sol-gel transition of the O/W emulsions was also very sensitive to pH. Thus, we have successfully prepared a novel double-stimuli responsive gel based on O/W emulsions consisting of C18AA and HCl. 相似文献
66.
Azobisisobutyronitlite (AIBN)-induced free radical polymerization of a methacrylate-based ionic liquid monomer, 1-(2-methacryloxyethyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (Met-IL) was carried out in a common organic solvent, N,N-dimethylformamide (DMF), and an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMImTFSI). The molecular weight of the obtained poly(Met-IL) was evaluated by transforming it to non-ionic poly(methyl methacrylate) with hydrolysis of the imidazolium-salt-substituted pendant ester groups and methyl esterification. Radical copolymerization with methyl methacrylate (MMA) was also carried out in both DMF and EMImTFSI. Analysis of copolymer composition revealed that the reactivity of Met-IL was lower than that of MMA in both DMF and EMImTFSI solutions. 相似文献
67.
Removal of hydrogen sulfide from methane using commercial polyphenylene oxide and Cardo-type polyimide hollow fiber membranes 总被引:1,自引:0,他引:1
Mahdi Pourafshari Chenar Houman Savoji Mohammad Soltanieh Takeshi Matsuura Shahram Tabe 《Korean Journal of Chemical Engineering》2011,28(3):902-913
The performance of commercially available poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) and Cardotype polyimide (PI) hollow fiber membranes was investigated in removing hydrogen sulfide from methane in a series of bench-scale experiments. It was observed that in the concentration range of hydrogen sulfide in methane from 101 to 401 ppm, the methane permeability decreased in the presence of hydrogen sulfide for Cardo-type polyimide hollow fiber membranes, whereas the PPO membrane performance was not affected. The separation coefficients of hydrogen sulfide/methane were 6 and 4 for PI and PPO membranes, respectively. Effects of temperature on the performance of PI and PPO membranes were investigated. It was observed that the permeabilities of both components of the mixture increased by increasing temperature, whereas the selectivities remained constant. 相似文献
68.
69.
Yoriko Tanaka Masahiro Furuta Koichi Kuriyama Ryosuke Kuwabara Yukiko Katsuki Takeshi Kondo Akira Fujishima Kensuke Honda 《Electrochimica acta》2011,(3):1172
Nitrogen-doped hydrogenated amorphous carbon thin films (a-C:N:H, N-doped DLC) were synthesized with microwave-assisted plasma-enhanced chemical vapor deposition widely used for DLC coating such as the inner surface of PET bottles. The electrochemical properties of N-doped DLC surfaces that can be useful in the application as an electrochemical sensor were investigated. N-doped DLC was easily fabricated using the vapor of nitrogen contained hydrocarbon as carbon and nitrogen source. A N/C ratio of resulting N-doped DLC films was 0.08 and atomic ratio of sp3/sp2-bonded carbons was 25/75. The electrical resistivity and optical gap were 0.695 Ω cm and 0.38 eV, respectively. N-doped DLC thin film was found to be an ideal polarizable electrode material with physical stability and chemical inertness. The film has a wide working potential range over 3 V, low double-layer capacitance, and high resistance to electrochemically induced corrosion in strong acid media, which were the same level as those for boron-doped diamond (BDD). The charge transfer rates for the inorganic redox species, Fe2+/3+ and Fe(CN)64−/3− at N-doped DLC were sufficiently high. The redox reaction of Ce2+/3+ with standard potential higher than H2O/O2 were observed due to the wider potential window. At N-doped DLC, the change of the kinetics of Fe(CN)63−/4− by surface oxidation is different from that at BDD. The rate of Fe(CN)63−/4− was not varied before and after oxidative treatment on N-doped DLC includes sp2 carbons, which indicates high durability of the electrochemical activity against surface oxidation. 相似文献
70.
The mechanical properties and morphological changes of poly(lactic acid) (PLA), polycarbonate (PC), and poly(butylene adipate‐co‐terephthalate) (PBAT) polymer blends were investigated. Several types of blend samples were prepared by reactive processing (RP) with a twin‐screw extruder using dicumyl peroxide (DCP) as a radical initiator. Dynamic mechanical analyses (DMA) of binary polymer blends of PC/PBAT indicated that each component was miscible over a wide range of PC/PBAT mixing ratios. DMA of PLA/PBAT/PC ternary blends revealed that PBAT is miscible with PC even in the case of ternary blend system and the miscibility of PLA and PBAT can also be modified through RP. As a result, the tensile strain and impact strength of the ternary blends was increased considerably through RP, especially for PLA/PBAT/PC = 42/18/40 (wt/wt/wt) with DCP (0.3 phr). Scanning electron microscopy (SEM) analysis of the PLA/PBAT/PC blends revealed many small spherical island phases with a domain size of approximately 0.05–1 μm for RP, whereas it was approximately 10 μm without RP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献