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101.
Yoshiyuki Sugahara Ken-Ichi Sugimoto Kazuyuki Kuroda Chuzo Kato 《Journal of the American Ceramic Society》1988,71(7):325-C
Both silicon carbide and aluminum silicon carbide have simultaneously been obtained directly from naturally occurring aluminosilicate by carbothermal reduction for the first time. A precursor of a montmorillonite–polyacrylonitrile (PAN) intercalation compound was heated at 1700°C in Ar. For comparison, montmorillonite–carbon mixtures were similarly heated. α-SiC, β-SiC, and Al4 Si2 C5 formed from the montmorillonite–PAN intercalation compound. Mainly α-Al4 SiC4 was obtained with ternary carbides from the montmorillonite–carbon mixtures in addition to a large amount of β-SiC. Hence, aluminum silicon carbide formation was affected by the mixing condition of the starting materials. 相似文献
102.
Seung-Min Oh Hyun-Ha Kim Atsushi Ogata Hisahiro Einaga Shigeru Futamura Dong-Wha Park 《Catalysis Letters》2005,99(1-2):101-104
Toluene was decomposed in a surface discharge plasma reactor packed with various zeolites. The positioning effect of the zeolite bed was also investigated Reactor-B, in which the zeolite bed was located upstream, performed much better than Reactor-A, in which the zeolite bed was located downstream. Furthermore, the decomposition efficiency in Reactor-B increased with the capacity for toluene adsorption on zeolite, while that in Reactor-A did not. The toluene adsorbed in micropores was not decomposed effectively by direct electron impact, but was decomposed by active oxygen species generated in the plasma zone on the zeolite surface. A good correlation was also observed between toluene decomposition and ozone consumption in the downward-type reactor. 相似文献
103.
Ichiro Kudo Toshiyuki Kato Hidetoshi Hayashi Ryohei Yanoshita Koichi Ikizawa Hiroko Uda Keizo Inoue 《Lipids》1991,26(12):1065-1070
We have previously reported that platelet-activating factor (PAF) induces proliferation and microbicidal activity of guinea
pig bone marrow cells. In the present study, we have found that the conditioned medium of PAF- or nonmetabolizable PAF agonist-treated
guinea pig bone marrow cells augmented DNA synthesis and induced microbicial activity of bone marrow cells. A PAF specific
antagonist, CV-6209, inhibited generation of the active conditioned medium by PAF. Addition of the PAF antagonist only partially
suppressed the augmentative effect of the active conditioned medium on DNA synthesis; this is consistent with the fact that,
because of the rapid breakdown, no appreciable amount of PAF remained in the conditioned medium of PAF-treated cells. Although
mouse bone marrow cells did not respond to PAF unlike guinea pig cells, their DNA synthesis was significantly enhanced by
the conditioned medium of PAF-treated guinea pig bone marrow cells. Thus, some newly generated factor(s) distinct from the
originally inoculated PAF seemed to modulate the bioactions of PAF on bone marrow cells. An appreciable amount of PAF was
produced by calcium ionophore-treated guinea pig bone marrow cells. These findings indicate that PAF synthesized in guinea
pig bone marrow cells induces generation in the cells of some factor(s) which affects proliferation or microbicidal activity.
Presented at The Third International Conference on Platelet-Activating Factor and Structurally Related Ether Lipids, Tokyo,
Japan, May 1989. 相似文献
104.
Monooctadecyl maleate, as a polymerizable surfactant, was synthesized by the mono-esterification of maleic anhydride and octadecanol,
and was utilized to surface-modify nano-Fe3O4 particles. A polymerizable magnetic fluid was obtained by directly dispersing modified nano-Fe3O4 particles into styrene monomer, and the polystyrene/nano-Fe3O4 composite was prepared through free radical polymerization of polymerizable magnetic fluid. The structure and dispersion
status in different dispersion phases of modified nano-Fe3O4 particles were studied by Fourier transform infrared (FTIR) spectrometry, X-ray diffraction (XRD) and transmission electron
microscopy (TEM), respectively. The experimental results show that the nano-Fe3O4 particles modified by monooctadecyl maleate with the size of about 7–10 nm can be uniformly dispersed into styrene and fixed
in the composite during the procedure of polymerization. Thermogravimetric analysis (TGA) and vibrating sample magnetometry
(VSM) indicate that the thermal stability of polystyrene/nano-Fe3O4 composite is improved compared to that of pure polystyrene, and the composite is a sort of superparamagnetic materials. 相似文献
105.
Atsushi Tanaka 《Carbon》2004,42(3):591-597
The present study confirmed that highly crystalline nanofibers with controlled structure may be prepared over Fe and Fe-Ni alloy catalysts. The degree of graphitization of various carbon nanofibers (CNFs) was analyzed by using C(0 0 2) peaks from the XRD profiles. The C(0 0 2) peaks of CNFs over Fe catalyst shifted to higher angle and became narrower as the preparation temperature increased from 560 to 620 °C. Tubular CNFs prepared at temperature higher than 630 °C showed lower 2θ angles compared to those of platelet fibers. CNFs prepared over Fe-Ni catalysts tended to resemble those prepared over Fe catalysts. The degree of graphitization of platelet CNFs resembled natural graphite, while d0 0 2 of the tubular CNFs showed values below the 3.39 Å reported as a theoretical minimum for a cylindrical alignment. Lc0 0 2 of platelet and tubular CNFs increased by heat treatment at 2000 and 2800 °C though d0 0 2 changed little. A transverse section of platelet and tubular CNFs had a hexagonal shape, not a round shape. The hexagonal column allows AB stacking of hexagonal planes that can give perfect hexagonal alignment. 相似文献
106.
The agronomic effectiveness of two natural phosphate rocks (PRs) from North Carolina (USA) and Togo and their 50% partially acidulated products (PAPRs) was evaluated in two greenhouse experiments using32P isotopic dilution techniques, namely L and AL values.In the first experiment rye grass was grown in a soil from Ghana. While the proportion of P in the plant derived from the P fertilizer (Pdff) ranged on. the average from about 10% for the PRs up to 80% for the PAPRs, the P fertilizer recovery was less than 1% for a 60-day growth period. In the second experiment, average values of P in the maize plants derived from the PAPRs ranged from 35% to 75% in 3 different soils. Both PRs were ineffective with the exception of North Carolina PR in the Seibersdorf soil. The P fertilizer recovery was 0.25% for the North Carolina PR in this soil whereas the recovery values ranged from 1.2% to 1.6% for the PAPRs.Mean values of the relative fertilizer efficiency estimated from the L values of each soil were less than 1% for the PRs whereas the values for the PAPRs which were dependent on soil type ranged from 20% up to 45%. The coefficient of relative effect of partial acidulation, that was calculated from the ratio of AL values for PR and PAPR in each soil indicated that partial acidulation increased the effectiveness of the natural PRs in all soils under study.This study showed that the use of32P isotope dilution techniques allows an accurate measurement of the P availability from natural and modified PR products to crops. Another advantage is that quantitative comparison of the P sources under study, PRs and PAPRs in this case, can be made even in soils where there is no response to the applied P sources. 相似文献
107.
H. Kominami J. Kato Y. Takada Y. Doushi B. Ohtani S. Nishimoto M. Inoue T. Inui Y. Kera 《Catalysis Letters》1997,46(3-4):235-240
Thermal decomposition of titanium(IV) tetra-tert-butoxide (TTB) in inert organic solvents at 573 K yielded microcrystalline
anatase (titanium(IV) oxide, TiO2) powders with a crystallite size of ca. 9 nm and a surface area of <100 m2 g-1. Primary and secondary alkoxides of titanium(IV), however, were not decomposed under similar conditions, indicating that
the thermal stability of C-O bonds in the alkoxides was a decisive factor for their decomposition. The TiO2 prepared from TTB by this manner was thermally stable upon calcination in air and retained high surface area of ca. 100 m2 g-1 even after calcination at 823 K. The as-prepared TiO2 powders, without calcination, exhibited much higher rate of carbon dioxide formation than any other active photocatalysts
such as Degussa P-25 and Ishihara ST-01 in the photocatalytic mineralization of acetic acid in aerated aqueous solutions.
The higher activity of the present TiO2 photocatalysts is attributed to both high crystallinity and large surface of the present product. The calcination of the
as-prepared TiO2 in air reduced the photocatalytic activity, but it was still higher than the other commercially available TiO2's.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
108.
α-Tocopherol was reacted with methyl linoleateperoxyl radicals at 37°C. The peroxyl radicals were generated by the reaction
of methyl linoleate with a free radical initiator, 2,2′-azobis(2,4-dimethylvaleronitrile). The primary products of α-tocopherol with methyl linoleate-peroxyl radicals were isolated by
reversephase and normal-phase high performance liquid chromatography (HPLC), and their structures were characterized by ultraviolet
(UV), infrared (IR),1H and13C nuclear magnetic resonance (NMR) and mass spectrometry (MS). There were four stereoisomers of methyl 13-(8a-peroxy-α-tocopherone)-9(Z),11(E)-octadecadienoate and four stereoisomers of methyl9-(8a-peroxy-α-tocopherone)-10(E),12(Z)-octadecadienoate. 相似文献
109.
Masahiro Kato Kazuaki Nakagawa Kenji Essaki Yukishige Maezawa Shin Takeda Ryosuke Kogo Yoshikazu Hagiwara 《International Journal of Applied Ceramic Technology》2005,2(6):467-475
We have discovered a series of lithium-containing oxides that immediately react with ambient carbon dioxide (CO2 ) up to 700°C. The products react and return reversibly to the oxides at a temperatures higher than about 700°C. The absorption capacity surpasses that of other CO2 absorbents by a factor of 10. Utilizing these absorbents, the possibility of a CO2 separation system that operates at around 500°C is proposed. It is generally believed that a CO2 separation process operable at temperatures higher than 500°C has the special benefit of a small energy penalty. Moreover, the absorption also proceeds at ambient temperature in the atmospheric environment. This property offers the possibility of many other applications, such as air cleaners or cartridges. Therefore, we think these materials have the potential to make a valuable contribution to the realization of CO2 emission control. 相似文献
110.
Silver-palladium alloy films were made by a thick-film technique using several metal powders prepared by the spray-pyrolysis method. Two types of powders were used: silver-palladium alloy powders (15 mol % Pd and 30 mol % Pd) and mixtures of silver and palladium powders. The fired films were about 2–3 m in thickness. The alloy particles sintered uniformly in firing, whereas, in the case of the powder mixtures, the alloying of silver and palladium particles caused uneven particle growth and large voids were formed in the fired films. For this reason the films made from the alloy powders had better conductive properties than those made from the powder mixtures. The resistivities of the films made from the alloy powders were close to the intrinsic value for silver-palladium alloys. Further, the oxidation of palladium during heating in air was significantly suppressed in the alloy powders when the palladium content was lower than 30 mol % in accordance with thermodynamic considerations. 相似文献