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101.
SiO2 nanoparticles (NPs) surface modified with polyethyleneimine-oleic acid complex (PEI-OA) has successfully prepared in a simple manner as a stabilizer of metal (Ni) fine particles (FPs) as well as a component of Ni/SiO2 composite particles. Starting from SiO2 NPs which were collected through centrifugation of commercial SiO2 colloids, it was found that PEI-OA can effectively adsorbed on collected SiO2 NPs surface during their redispersion process in toluene with the assistance of ultrasonication. The aggregated particle size (Z-average size) in toluene could be successfully reduced to c.a. 100 nm under saturated adsorption of PEI-OA. It was also found that PEI-OA-modified SiO2 NPs can effectively attach to the Ni FPs by a simple mixing process in toluene. The FE-SEM observation confirmed the adsorption of the PEI-OA-modified SiO2 NPs on the Ni FPs without forming severe NP aggregates. Owing to the attachment of the PEI-OA-modified SiO2 NPs with surfaces that are compatible to toluene and α-terpineol, the suspension stability of the Ni/SiO2 composite particles in these solvents drastically improved. The result was confirmed by the effective reduction of the sedimentation velocity of diluted suspensions as well as by the reduction of the viscosity of dense suspensions. 相似文献
102.
Wave conversion materials with high thermal conductivity are necessary for high-power semiconductor lighting. Ceramics have higher thermal conductivity than existing matrices such as resin or glass in which phosphor particles are dispersed. However, the high densification of ceramics generally requires high-temperature sintering, which degrades and alters the phosphor particles. In this study, we aimed to achieve the high densification of MgO ceramics at room temperature. Applying high hydrostatic pressure with water addition improved the sample packing ratio and promoted the formation of Mg(OH)2. As a result, the relative density was ≥95%. Additionally, various nitride phosphor particles (CaAlSiN3:Eu2+, β-SiAlON:Eu2+, and α-SiAlON:Eu2+) were dispersed in the MgO matrix at room temperature without degrading the luminescence property. The thermal conductivity of the obtained sample was about 8 W m?1K?1, 40 times higher than that of the epoxy matrix. 相似文献
103.
Shape-selective properties of octadecyltrichlorosilane-treated H-ZSM-5, abbreviated as H-ZSM-5-C18, have been observed in the hydrolysis of esters having some rings and lactones in toluene-water solvent system. The shape-selectivity for the reaction has been evaluated by the ratio
of the relative rate constants in comparison with the rate constant of methyl acetate. The selectivity became higher with increase in bulkiness of the substrate. Substrates having the minimum diameter larger than 6.5 Å, significantly larger in size than the pore openings of ZSM-5, could not react in this system. 相似文献
104.
Kazuki Yanome Takayuki Kiba Midori Kawamura Yoshio Abe Kyung Ho Kim Junichi Takayama Akihiro Murayama 《Journal of Electronic Materials》2017,46(7):3873-3879
We report the ellipsometric and photoluminescence (PL) properties of Indium zinc oxide (IZO) films, which were grown by radio frequency sputtering under Ar and O2 atmospheres. IZO films grown under an O2 atmosphere (IZO (O2)) showed enhanced PL properties when compared to the films grown under an Ar atmosphere (IZO (Ar)), particularly with respect to the band-edge emission. The enhancement of band-edge emission can be attributed to the reduction in the non-emissive defect states related to oxygen vacancies, which were repaired by sputtering under O2 atmosphere, whereas the PL enhancement in green region is probably due to the formation of the different types of defects under the excess oxygen environment. This was also supported by the results of time-resolved PL measurements, where the band-edge emission of IZO (Ar) showed rapid decay with a 50 ps lifetime, which indicates the dominance of the relaxation pathway to underlying defect states. In contrast, the PL decay profiles of IZO (O2) for band-edge and emissive defect states showed moderate decay with time-constants of 2.3 ns and 5.7 ns, respectively. The exciton relaxation dynamics were sensitive to the presence and its kinds of defect states, which were controlled by the growth conditions. 相似文献
105.
106.
107.
We examined production levels of dye-decolorizing peroxidase (rDyP) by recombinant Aspergillus oryzae using wheat bran and rice bran powders in repeated-batch and fed-batch cultures. Similar average rDyP productivities were observed in repeated-batch cultures using wheat bran powder and rice bran powder. Average rDyP productivities in fed-batch cultures were slightly lower than those in repeated-batch cultures. The rDyP production was affected by the addition of K(2)HPO(4) in the repeated-batch and fed-batch cultures using wheat bran powder. All average rDyP productivities in this study were significantly higher than those for any other peroxidases previously reported. 相似文献
108.
Toshiaki Momose Yoshiya Yamaguchi Takashi Iida Junichi Goto Toshio Nambara 《Lipids》1998,33(1):101-108
The structure-retention correlation of various C24 bile acid isomers was studied by the addition of methyl β-cyclodextrin (Me-β-CD) to mobile phases in reversed-phase high-performance
liquid chromatography (HPLC). The compounds examined include a series of monosubstituted bile acids related to cholanoic acids
differing from one another in the position and configuration of an oxygen-containing function (hydroxyl or oxo group) at the
position C-3, C-6, C-7, or C-12 and the stereochemistry of the A/B-ring fusion (trans 5α-H and cis 5β-H) in the steroid nucleus. The inclusion HPLC with Me-β-CD was also applied to biologically important 4β- and 6-hydroxylated
bile acids substituted by three to four hydroxyl groups in the 5β-steroid nucleus. These bile acid samples were converted
into their fluorescence prelabeled 24-pyrenacyl ester derivatives and chromatographed on a Capcell Pak C18 column eluted with methanol-water mixtures in the presence or absence of 5 mM Me-β-CD. The effects of Me-β-CD on the retentions
of each compound were correlated quantitatively to the decreasing rate of capacity factors and the relative strength of host-guest
inter-actions. On the basis of the retention data, specific and nonspecific hydrogen-bonding interactions between the bile
acids and the Me-β-CD were discussed. 相似文献
109.
The sorption behavior of CO2 gas in photocrosslinked poly(vinyl cinnamate) film was examined under atmospheric pressure. The sorption isotherm was well described by the Langmuir equation, suggesting that sorption of CO2 is mainly governed by adsorption in the microvoids. The amount of sorbed CO2 was significantly affected by the degree of crosslinking. The CO2 sorption was enhanced at a lower degree of crosslinking but was decreased at a higher degree of crosslinking. The unexpected increase in the amount of adsorbed CO2 correlated with the increase in the number of microvoids that occurred as a result of the crosslinking reaction. However, further crosslinking led to a decrease in the mean size of the microvoids. The smaller microvoids, in comparison to CO2 molecules, did not act as adsorption sites, so that the amount of sorbed CO2 decreased. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1744–1750, 2000 相似文献
110.
Makoto Yamaguchi Shoichi Shichimiya Shinji Ishibe Naomi Furuse Masahiro Kobayashi Toshihiro Suzuki Junichi Shimizu Susumu Nishiki 《Electrical Engineering in Japan》2000,131(3):34-42
New zinc oxide elements with a varistor voltage about twice that of conventional ones have been developed by reducing the ZnO grain size with a new additive, making it possible to halve the series number of elements in metal oxide surge arresters. The advanced arresters with these elements for GIS are smaller in volume by 40 to 60% compared with conventional ones. These advanced MOAs increase the flexibility in positioning MOAs and optimizing the GIS layout. This paper describes the performance of the new elements, the specification and construction of the advanced MOAs, and the results of typical evaluation tests. © 2000 Scripta Technica, Electr Eng Jpn, 131(3): 34–42, 2000 相似文献