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排序方式: 共有431条查询结果,搜索用时 0 毫秒
91.
Tessui Nakagawa Takayuki Ichikawa Keiji Shimoda Masami Tsubota Hiroki Miyaoka Shigehito Isobe Tetsuo Honma Shinji Michimura Fumitoshi Iga Somei Ohnuki Yoshitsugu Kojima 《International Journal of Hydrogen Energy》2013
The mixtures of scandium hydride ScH2 and metal boride MBn, which is MgB2 or CaB6, were hydrogenated by mechanical milling under hydrogen pressure at room temperature. ScH2–MgB2 and ScH2–CaB6 desorbed 3.4 and 2.3 mass% of H2, respectively, with peaks below 300 °C. The results of synchrotron radiation X-ray powder diffraction and X-ray absorption spectroscopy at the Sc K-edge indicated that ScB2 was produced by milling. Fourier-transform infrared spectroscopy suggested that hydrogen was stored as B–H bonds in the as-milled samples. Nuclear magnetic resonance spectroscopy clarified the presence of metal borohydrides M(BH4)2 (M = Mg and Ca) in the as-milled ScH2–MBn mixtures. These results indicate that M(BH4)2 is synthesized by milling the ScH2–MBn mixtures under hydrogen pressure at room temperature, and hydrogen was desorbed from M(BH4)2. The by-products of M(BH4)2 are MgH2 in the M = Mg case, which was observed by transmission electron microscopy, and ScB2 in both cases. 相似文献
92.
Rakan Matsui Masaaki Hasegawa Masami Ishida Toshiya Ebata Noriyuki Namiki Kenji Sugibayashi 《Drug development and industrial pharmacy》2013,39(8):729-738
ABSTRACTIn vitro permeation of lidocaine (lidocaine base, LID) through excised rat skin was investigated using several LID-suspended oily formulations. The first skin permeation of LID from an LID-suspended oily solution such as liquid paraffin (LP), isopropyl myristate (IPM), polyoxyethylene (2) oleylether (BO-2), and diethyl sebacate (DES) was evaluated and compared with that from polyethylene glycol 400 (PEG400) solution, a hydrophilic base. The obtained permeation rate of LID, Japp, from PEG400, LP, IPM, BO-2, and DES was in the order of DES>BO-2 = IPM>LP>PEG400, and increased with LID solubility in the oily solvents, although LID crystals were dispersed in all solvents. Subsequently, oily formulations that consisted of different ratios of the first oily solvent (IPM, BO-2, or DES) (each 0–20%), the second oily solvent (LP) and an oily mixture of microcrystalline wax/white petrolatum/paraffin (1/5/4) were evaluated. BO-2 groups at a concentration of 5% and 10% had the highest Japp among the oily formulations, although a higher BO-2 resulted in lower skin permeation. In addition, pretreatment with BO-2 increased the skin permeation of LID. These results suggest that the penetration enhancing effect by the system may be related to the skin penetration of BO-2 itself. Finally, mathematical analysis was done to evaluate the effect of BO-2, and it was shown that BO-2 improved the LID solubility in stratum corneum lipids to efficiently enhance the LID permeation through skin. 相似文献
93.
The distribution behavior of n-alcohols, ketones and nitroalkanes in aqueous liquid chromatography with a column packed with polyethylene glycol (PEG) gel, TSKgel Ether-250, was compared with that in aqueous two-phase systems (ATPSs) formed from PEG and Na2SO4 or (NH4)2SO4. The plots of the distribution data obtained for the PEG gel system against those for the ATPS reveal that the separation selectivities exerted by the PEG gel system and the PEG-based ATPS are approximately the same. Differential scanning calorimetry studies on aqueous PEG solutions suggest that PEG polymer forms a hydration structure of which the composition is 50% (w/w) PEG or the hydration number per ethylene oxide is 2.4 and the separation selectivity of the PEG-water systems can be attributed to partition of solute compounds into the hydrated PEG polymer structure. 相似文献
94.
Cryogenic optical measurements of 12-segment-bonded carbon-fiber-reinforced silicon carbide composite mirror with support mechanism 总被引:1,自引:0,他引:1
Kaneda H Nakagawa T Onaka T Enya K Makiuti S Takaki J Haruna M Kume M Ozaki T 《Applied optics》2008,47(8):1122-1128
A 720 mm diameter 12-segment-bonded carbon-fiber-reinforced silicon carbide (C/SiC) composite mirror has been fabricated and tested at cryogenic temperatures. Interferometric measurements show significant cryogenic deformation of the C/SiC composite mirror, which is well reproduced by a model analysis with measured properties of the bonded segments. It is concluded that the deformation is due mostly to variation in coefficients of thermal expansion among segments. In parallel, a 4-degree-of-freedom ball-bearing support mechanism has been developed for cryogenic applications. The C/SiC composite mirror was mounted on an aluminum base plate with the support mechanism and tested again. Cryogenic deformation of the mirror attributed to thermal contraction of the aluminum base plate via the support mechanism is highly reduced by the support, confirming that the newly developed support mechanism is promising for its future application to large-aperture cooled space telescopes. 相似文献
95.
96.
To understand the effect of the percolated clay network structure formed by the exfoliated clay layers in nanocomposites, the clay network structure in nylon‐6‐based nanocomposites is characterized using TEM and FFT analyses. A MMT volume fraction between 0.013 and 0.014 is the percolation threshold for strong network formation. The volume spanning MMT network leads to a very high flow activation energy as compared with that of neat nylon 6, resulting in the pseudo‐solid like response under molten state in N6CNs. A canonical NVT‐MD simulation was conducted in the system made up by nylon 6 molecules/Si(OH)4 molecules. The formation of the strong interfacial interaction between nylon 6 molecules and Si(OH)4 molecules induced by OH groups is suggested.
97.
98.
Tsuyoshi Nishi Akinori Itoh Masahide Takano Masami Numata Mitsuo Akabori Yasuo Arai Kazuo Minato 《Journal of Nuclear Materials》2008,376(1):78-82
The thermal diffusivity of neptunium dioxide was measured in the temperature range from 473 to 1473 K by using a laser flash method. The thermal diffusivity slightly decreased with increasing temperature in the temperature range investigated. The heat capacity of NpO2 was measured in the temperature range from 334 to 1071 K by using a drop calorimetry method. The heat capacity of NpO2 determined in this study was slightly larger than that of UO2 and about 7% smaller than that of PuO2. The thermal conductivity of NpO2 was determined from the thermal diffusivity, the heat capacity and the bulk density. It was found that the thermal conductivity of NpO2 from 873 to 1473 K lay between those of UO2 and PuO2. 相似文献
99.
Masami Kudo Evgueni Jak Peter Hayes Katsunori Yamaguchi Yoichi Takeda 《Metallurgical and Materials Transactions B》2000,31(1):15-24
Experiments have been carried out to determine the equilibria between FeO
x
-CaO-SiO2 slag and lead metal in iron crucibles at temperatures ranging from 1473 to 1573 K. It has been found that the highest lead
solubilities are observed in the silica-saturated iron silicate slags, while the lowest solubilities are observed in the CaO-saturated
calcium ferrite slags. The activity coefficient of PbO varies from 0.15 to 3, depending on the slag composition. Changes in
temperature do not have a significant impact on the activity coefficient. The activity of FeO and pct Fe3+/pct Fe2+ ratios have been determined as a function of slag composition. These new experimental data have been incorporated into an
optimized thermodynamic slag model using the computer package FACT. 相似文献
100.
Tatsumi Ishihara Toshiaki Takagi Masami Ito Hiroyasu Nishiguchi Yusaku Takita 《Journal of Electroceramics》2000,4(1):207-214
Preparation of CuO-BaTiO3 mixed oxide thin film by the decomposition of a self-assembled multibilayer film as a molecular template was investigated in this study. Furthermore, CO2 sensing property of the resultant thin film was investigated as a capacitive type sensor. The self-assembled bilayer film of few 1000 layers thickness can be obtained easily by casting an aqueous suspension consisting of dimethyldihexadecylammoiun bromide (DC1-16), Cu(ClO4)2, Ba(TiO(C2H4)2), 2,6-dimetyle-3,5heptadione (DHP), and polyvinyl alcohol. Divalent copper ion (Cu2+)) which is associated with 2 DHP molecules was incorporated into the molecular bilayer film and BaTiO3 precursor exists at the interspace of molecular bilayer film by coordinating with polyvinyl alcohol. Upquenching the organic-inorganic film at 1173 K leads to the uniform film of CuO-BaTiO3 oxide mixture. Although operating temperature shifted to higher temperature, the resultant film exhibits the capacitance change upon exposure to CO2. Consequently, it is concluded that the mixed oxide film of CuO-BaTiO3 prepared by the decomposition of multibilayer film was also an appropriate capacitive type CO2 sensor. 相似文献