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991.
Palladium acetate together with a newly synthesized silsesquioxane- pyridyl ligand showed excellent catalytic activity towards
the aerobic oxidation of benzyl alcohol to benzaldehyde. TEM measurements revealed the in situ formation of Pd nanoclusters during the reaction period. 相似文献
992.
Hong-Joo Lee Hiroyuki Suda Kenji Haraya Dong-Pyo Kim 《Korean Journal of Chemical Engineering》2006,23(3):435-440
Of thermosetting polymers, polyphenylene oxide (PPO) is considered as one of the promising alternative polymeric precursors
for carbon membrane preparation. In this study, the PPO derived carbon membranes were prepared by carbonization and followed
by air-oxidation as post-treatment method to modify the membrane pore structures. The characterization of the pore properties
showed that air-oxidation enlarged the pore structure for the postoxidized carbon materials. The permeation results for the
post-oxidized carbon membranes showed that the extent of the permeation modification was strongly dependent on the oxidation
temperature. In the binary mixture gas systems, the permeation performance of the adsorbing gas species increased due to the
surface diffusion mechanism. It is considered in the oxidation effect on the permeation modification that the post-oxidation
of the carbon membranes increased gas permeation and separation properties. 相似文献
993.
Masaaki Nagatsu Takaaki Yoshida Marcel Mesko Akihisa Ogino Takafumi Matsuda Takayuki Tanaka Hirokazu Tatsuoka Kenji Murakami 《Carbon》2006,44(15):3336-3341
The use of graphene layer encapsulated catalytic metal particles for the growth of narrower multi-walled carbon nanotubes (MWCNTs) has been studied using plasma-enhanced chemical vapor deposition and conventional thermal CVD. Ni–C or Fe–C composite nanoclusters were fabricated using the dc arc discharge technique with metal–graphite composite electrodes carrying a current of 100–200 A in a stainless-steel chamber filled with He and CH4 mixture gas at 27 kPa. Nano-sized grains with diameters less than 10 nm were fabricated and deposited on a Si substrate, and were used as a catalyst for MWCNT growth. Structural analyses of the composite nanoclusters and MWCNTs were carried out using transmission electron microscopy. The results show that the diameters of the MWCNTs were reduced from 50–100 nm for a conventional Ni thin film-evaporated Si substrate to a minimum of roughly 2–4 nm in the present study. 相似文献
994.
Masahiro Endo Yasuyuki Morishima Shinichi Yano Kenji Tadano Yukinobu Murata Kenji Tsunashima 《应用聚合物科学杂志》2006,101(6):3971-3978
Miscibility was studied for four polyamide blends of 6I/6T [copolymer consisting of 1,6‐hexamethylene diamine and isophthalic acid (6I) (70 wt %) and terephthalic acid (6T) (30 wt %)] with MXD6 (polyamide of m‐xylenediamine and adipic acid), BAC6 (polyamide of 1,3‐bis(aminomethyl)cyclohexane and adipic acid), TR55 (copolymer consisting of nylon 11 (30 wt %), and polyamide of bis(3‐methyl, 4‐aminocyclohexyl)methane (30 wt %) and isophthalic acid (70 wt %), and CX7323 (polyamide of bis(4‐aminocyclohexyl)methane and dodecanedicarboxylic acid), using differential scanning calorimetry, X‐ray diffraction method, and electronmicroscopic observation. In quenched MXD6/(6I/6T) and BAC6/(6I/6T) blends, MXD6 and BAC6 components were miscible to 6I/6T, but TR55 and CX7323 components were completely phase‐separated from 6I/6T. Interestingly on electronmicroscopic observations, TR55 and CX7323 components were seen as droplets in 6I/6T medium when the content is low, but when 50 wt %, a layered structure was constructed with 6I/6T, reminiscent of morphological structure in block copolymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3971–3978, 2006 相似文献
995.
Yutaka Shinoda Michiyuki Yoshida Takashi Akatsu Fumihiro Wakai 《Journal of the American Ceramic Society》2004,87(10):1919-1926
The deformation behavior of boron- and carbon-doped β-silicon carbide (B,C-SiC) with an average grain size of 260 ± 18 nm containing 1 wt% boron was investigated by compression testing at elevated temperatures. Extensive grain growth during deformation was observed. The stress–strain curves were compensated for grain growth by assuming power-law type of dependence on grain size and strain rate. The stress exponent n was ∼1.3 and the grain size exponent p was ∼2.7 at temperatures ranging from 1593° to 1758°C. The apparent activation energy of deformation Q d was ∼760 kJ/mol, which was lower than the activation energy for lattice diffusion of silicon and carbon in SiC and higher than that for grain-boundary diffusion of carbon in SiC. These results suggest that the deformation mechanism of the fine-grained B,C-SiC is grain-boundary sliding accommodated by the grain-boundary diffusion. 相似文献
996.
The aim of the present study was to compare the effects of a low-fat diet enriched with oleic acid to those of a low-fat diet
enriched with linoleic acid on fasting lipids, postprandial lipemia, and oxidative susceptibility of low-density lipoprotein
(LDL) in patients with type 2 diabetes mellitus (DM). In a 3-wk randomized crossover study, eight patients with type 2 DM
were given an experimental low-fat diet enriched with either oleic acid or linoleic acid. The oleic-acid-enriched diet contained
5, 15, and 5% energy from saturated, monounsaturated, and polyunsaturated fatty acids, and the linoleic-acid-enriched diet
contained 5, 5, and 15% energy from saturated, monounsaturated, and polyunsaturated fatty acids, respectively. In addition
to evaluating the fasting lipids and oxidative susceptibility of LDL, we evaluated postprandial lipemia using an oral fat
load at the end of each 3-wk dietary phase. There were no significant differences in fasting lipid profile or lag time of
LDL oxidation between the two experimental dietary phases. The average and maximal increments of remnant-like particle (RLP)
cholesterol levels during oral fat load were significantly higher after the oleic-acid-enriched dietary phase than after the
linoleic-acid-enriched dietary phase. The area under the curve of RLP cholesterol was also significantly larger after the
oleicacid-enriched dietary phase than after the linoleic-acid-enriched dietary phase. These results suggest that the oleic-acidenriched
diet was associated with increased formation of postprandial chylomicron remnants compared with the linoleicacid-enriched
diet. 相似文献
997.
Kenji Tsuchihara Toshio Masuda Toshinobu Higashimura Masakazu Nishida Hiroshige Maramatsu 《Polymer Bulletin》1990,23(5):505-511
Summary [2,5-Bis(trifluoromethyl)phenyl]acetylene [BTFPA; HCCC6H3-2, 5-(CF3)2]polymerized with W, Mo, and Nb catalysts to produce methanol-insoluble polymers in high yields. The poly(BTFPA) produced by the W(CO)6-based catalyst at 30 °C was soluble in p-(CF3)2C6H4, and had relatively high molecular weight ([]=0.352 dL/g in p-(CF3)2C6H4). The main chain of the polymer was composed of alternating double bonds, and the polymer was a dark brown solid. The temperature at which the weight loss of the polymer started was higher than 300 °C. The polymerization behavior and polymer properties for BTFPA are compared with those for phenylacetylene and [o-(trifluoromethyl)phenyl]acetylene. 相似文献
998.
Dense carbon films of about 20 μm in thickness were prepared from a commercially available cellulose film of 40 μm thick by heat treatment up to 900°C. Carbon films thus obtained were heat treated at temperatures between 1800 and 3000°C for 30–60 min. The heat-treated carbon films were investigated by the measurements of resistivity, Hall coefficient and magnetoresistance at liquid nitrogen temperature. Reflected and transmitted X-ray diffraction experiments and observations by a high-resolution scanning electron microscope (SEM) were also carried out. The results of the resistivity and Hall coefficient for high-temperature-treated specimens indicated that the carbonized film was more graphitizable than bulk glass-like carbons. The magnetoresistance and X-ray diffraction profiles for the high-temperature-treated specimens suggested that each of these specimens substantially consisted of the matrix of granular microtexture and the graphite layer skin. The skin was clearly observed by SEM for the specimens heat-treated at 2800 and 3000°C and their thickness was 100–300 nm. 相似文献
999.
Rolling contact fatigue of alumina ceramics sprayed on steel roller under pure rolling contact condition 总被引:4,自引:1,他引:4
Masahiro Fujii Akira Yoshida Jiabin Ma Sadato Shigemura Kazumi Tani 《Tribology International》2006,39(9):856-862
The rolling contact fatigue of sprayed alumina ceramics with a nominal composition of Al2O3–2.3 mass% TiO2 was studied with a two-roller test machine under a pure rolling contact condition with oil lubricant. The influence of undercoating of sprayed Ni-based alloy on the rolling contact fatigue was investigated. The failure mode of all sprayed rollers was spalling caused by subsurface cracking. The undercoating did not contribute to the improvement of the rolling contact fatigue life. The elastic modulus of the alumina sprayed layer evaluated with the nano-indentation method was around 85 GPa. The depths of the observed subsurface cracks corresponded approximately to the depths where the orthogonal shear stress or the maximum shear stress calculated with two-dimensional FEM became maximum. 相似文献
1000.
Nakamori H Matsuyama S Imai S Kimura T Sano Y Kohmura Y Tamasaku K Yabashi M Ishikawa T Yamauchi K 《The Review of scientific instruments》2012,83(5):053701
To construct adaptive x-ray focusing optics whose optical parameters can be varied while performing wavefront correction, ultraprecise piezoelectric deformable mirrors have been developed. We computationally and experimentally investigated undesirable short-period deformation caused by piezoelectric actuators adhered to the substrate during mirror deformation. Based on the results of finite element method analysis, shape measurements, and the observation of x-ray reflection images, a guideline is developed for designing deformable mirrors that do not have short-period deformation errors. 相似文献