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61.
In this article, we report the influence of the polyimide molecular weight (1.2 × 105, 2.6 × 105, and 4.1 × 105) on the structure and the gas permeation properties of asymmetric polyimide membranes made by the dry–wet phase‐inversion process. The apparent skin layer thickness of the asymmetric membrane increased with increasing molecular weight, and the thicknesses of the membranes prepared from the three polyimides with a casting polymer solution containing 8.0 wt % butanol were 132, 350, and 739 nm, respectively. That is, the gas permeance in the asymmetric membranes increased with decreasing molecular weight. In contrast, the gas selectivity of the asymmetric membranes did not depend on the skin layer thickness. The solvent evaporation in the dry phase‐inversion process and the nonsolvent diffusion in the dry process were important factors that determined the formation of the asymmetric membrane. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
62.
63.
Takashi Itoh Hitoe Habuchi Shoji Nitta Shuichi Nonomura 《Fullerenes, Nanotubes and Carbon Nanostructures》1994,2(2):181-187
Gas effusion spectra of fullerenes are studied. Three peaks of toluene are found in gas effusion spectra dp/dT-T. Two peaks of oxygen are found in gas effusion spectra dN/dt-T of samples kept in the air after annealing to avoid the toluene. These phenomena confirmed to be reversible are discussed by treating fullerenes as intercalated materials. 相似文献
64.
Kikuhito Kawasue Shoji Sakai Terufumi Wakiyama Shigeki Oyama Hisashi Senda 《Artificial Life and Robotics》2008,13(1):336-340
The 3D quantitative measurement system for a sewer pipe is introduced. Two parallel lasers are rotated by the motor and draw
the two annular streaks on the inside surface of the pipe. The circular laser streaks are recorded by the CCD camera. The
measurement of the cross-section is established by analyzing the recorded streaks. The tilt of the robot against the axis
of the pipe is detected by the deviation between two parallel lasers. It enables us to measure the vertical cross section
of the pipe regardless the tilt of the system to the pipe. Experimental result shows the feasibility of the system.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
65.
Shoji Nagaoka Masanori Nagata Kenji Arinaga Kiyoshi Shigemori Makoto Takafuji Hirotaka Ihara 《Coloration Technology》2007,123(6):344-350
In order to develop environmentally friendly coloured materials, cellulose composite spherical microbeads hybridised with titanium dioxide (TiO2 ) particles and inorganic pigment were prepared by a phase-separation method using viscose and an aqueous solution containing sodium polyacrylate. Findings regarding the relationships between cellulose xanthate and the electronic characteristics of TiO2 particles used in the cellulose/inorganic material composite sphering process are also reported. These findings suggest that the location of TiO2 particles in cellulose microbeads is related to electrical repulsion between the xanthate (CSS− ) group and TiO2 . The use of TiO2 powder as colour pigment is limited, as its colour is white. The cellulose composite spherical microbeads covered with TiO2 and Fe2 O3 particles were developed by addition of iron oxide (Fe2 O3 ). Their surfaces were viewed by laser microscope and using SEM images. These composite microbeads retained the photocatalytic property of TiO2 . Cellulose/TiO2 /Fe2 O3 composite spherical microbeads with both colour function and photocatalytic properties were successfully prepared. 相似文献
66.
Y Saitoh K Gu S Kin M Yamauchi T Sasaki S Nosaka M Hashimoto K Nakayama K Tamura 《Canadian Metallurgical Quarterly》1996,28(1):286-288
67.
Takayuki Kumada Shoji Mori Toshimitsu Nagasaka Jun Kumagai Tetsuo Miyazaki 《Journal of Low Temperature Physics》2001,122(3-4):265-277
The tunneling abstraction reaction: H+H2H2+H in -irradiated solid hydrogen has been studied using electron spin resonance (ESR) and electron-nuclear double resonance (ENDOR) spectroscopy and gas-chromatography. The rate constant for the tunneling reaction in solid hydrogen was found to decrease with the increase in the concentration of ortho-H2 molecules in solid hydrogen. We concluded that the decrease in the rate constant is due to the energy level mismatching between reactant species of H+H2 trapped and product species of H2+H trapped in the reverse induced by inhomogeneous intermolecular interactions between ortho-H2 molecules in solid hydrogen. This result indicates that resonance effects play an important role in tunneling reactions in solids. 相似文献
68.
Shigeru Ohshima Yasuto Fujimaki Minoru Takekawa Shoji Fujisawa 《Polycyclic Aromatic Compounds》2013,33(3-4):433-440
To identify nitrobenzanthrones (NBAs) such as 3-nitro-7 H -benz[ de ]anthracene-7-one (3-NBA) on the basis of their electronic spectral data, we have synthesized 1-, 2-, 3-, 9-, and 10-NBAs and measured their absorption and emission spectra. The first strong absorption band of the NBAs appeared in the region 350-440 nm; the band of 10-NBA was red-shifted by about 20 nm. The molar absorptivities of 3- and 9-NBA were about two times as large as those of the others. The fluorescence spectra of the NBAs varied more largely with the position of the nitro group compared to the absorption spectra. The quantum yields of fluorescence were very small, ranging from ~10 m 2 for 2- and 10-NBA to ~10 m 4 for 1- and 3-NBA. 3-NBA exhibited a characteristic spectrum with two broad bands at 450 and 530 nm. On excitation causing an n ~ * transition in the NBAs, their fluorescence intensities increased by a factor of 10. Phosphorescence was observed at 77 K for all compounds though that of 1-NBA was very weak. These results give the promise of characterizing individual isomers of NBAs on the basis of their spectroscopic data. 相似文献
69.
Suitable catalysts for the decomposition of methane into carbon and hydrogen and for the regeneration of methane by hydrogenation of the carbon have been looked for in a series of transition metals and precious metals supported on various carriers. The most active catalyst for both reactions was Ni/SiO2. The carbon formed on this catalyst was thermodynamically less stable than graphite. The different rate equations for the decomposition of methane obtained for the fresh and carbon deposited Ni/SiO2 suggest that the rate-determining steps are different for the two catalysts. The highest number of carbon atoms deposited per one Ni atom was 31 at 773 K. However, the number of methane molecules recovered easily at 773 K was limited to 1.5 per Ni atom.
A physical mixture of Ni/SiO2 and CaNi5, a hydrogen-absorbing alloy, enhanced the decomposition rate of methane, enabling the complete conversion of methane at 773 K beyond the thermodynamic limitation. The presence of CaNi5 at 273 K separated from the catalyst in a reaction system further enhanced the decomposition of methane due to an increased hydrogen-absorbing capacity of the CaNi5 at low temperatures. The carbon deposited on Ni/SiO2 in this case was reactive to be hydrogenated back to methane at 773 K, giving an average 7.5 CH4 molecules per one Ni atom. 相似文献
70.