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11.
12.
Kenji Okada Yuichiro Takamatsu Yasuaki Tokudome Atsushi Nakahira Masahide Takahashi 《Journal of Sol-Gel Science and Technology》2013,65(1):36-40
Synthesis of titanate nanotubes (TNTs) from sol–gel derived amorphous TiO2 thin films under moderate hydrothermal condition has been reported. TNTs from film possess a tubular morphology that is the same crystalline phase as one synthesized from TiO2 powder so far. TNTs obtained in this study are not entangled one another but oriented and isolated on the substrate. Growth of highly oriented TNTs is observed in micro grooves of amorphous TiO2 thin film. Their orientation is also maintained with the growth of TNTs. 相似文献
13.
We study the temperature evolution of aluminum nanoparticles generated by femtosecond laser ablation with spatiotemporally resolved x-ray-absorption fine-structure spectroscopy. We successfully identify the nanoparticles based on the L-edge absorption fine structure of the ablation plume in combination with the dependence of the edge structure on the irradiation intensity and the expansion velocity of the plume. In particular, we show that the lattice temperature of the nanoparticles is estimated from the L-edge slope, and that its spatial dependence reflects the cooling of the nanoparticles during plume expansion. The results reveal that the emitted nanoparticles travel in a vacuum as a condensed liquid phase with a lattice temperature of about 2500 to 4200 K in the early stage of plume expansion. 相似文献
14.
Synergistic Spin Transition between Spin Crossover and Spin‐Peierls‐like Singlet Formation in the Halogen‐Bonded Molecular Hybrid System: [Fe(Iqsal)2][Ni(dmit)2]⋅CH3CN⋅H2O
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Kappei Fukuroi Prof. Dr. Kazuyuki Takahashi Prof. Dr. Tomoyuki Mochida Dr. Takahiro Sakurai Prof. Dr. Hitoshi Ohta Dr. Takashi Yamamoto Prof. Dr. Yasuaki Einaga Prof. Dr. Hatsumi Mori 《Angewandte Chemie (International ed. in English)》2014,53(7):1983-1986
To introduce halogen‐bond interactions between a cation and an anion, a novel FeIII complex from iodine‐substituted ligands involving a paramagnetic nickel dithiolene anion was prepared and characterized. The compound exhibited the synergy between a spin‐crossover transition and a spin‐Peierls‐like singlet formation. The halogen‐bond interactions between the iodine and the sulfur atoms stabilized the paramagnetic state of π‐spins and played a crucial role in the synergistic magnetic transition between d‐ and π‐spins. In addition, the compound showed the light‐induced excited spin state trapping effect. 相似文献
15.
Inukai J Wakisaka M Yamagishi M Itaya K 《Langmuir : the ACS journal of surfaces and colloids》2004,20(18):7507-7511
Hydroquinone (HQ) adlayers were formed on Pt(111) in HF solution and in a vacuum. By using scanning tunneling microscopy (STM) in solution, it was revealed that HQ formed an ordered structure on Pt(111) with a strong attractive interaction between two adjacent hydroxyl groups in neighboring HQ molecules. After the sample was transferred into a vacuum, low-energy electron diffraction (LEED) measurement was performed, which showed that the (2.56 x 2.56)R16 degrees incommensurate structure of the HQ adlayer was formed in solution. The HQ adlayer on Pt(111) was formed also by vapor deposition, and the identical (2.56 x 2.56)R16 degrees adlayer structure was found by LEED and STM in a vacuum. 相似文献
16.
The observation of slow-wave sustained (SW) discharge in a whistler- or helicon-wave range of frequency is made using high-frequency and very-high-frequency bands of rf. The SW discharge occurs at an extremely low rf power and plasma density, which are lower than a capacitive-coupling discharge region. 相似文献
17.
Treatment of sulfur-substituted aromatic lactams with carbonyl compounds in the presence of samarium(II) diiodide was found to undergo novel tandem desulfurization and reductive coupling reactions to generate -hydroxyalkylated lactams in high yield. Stereochemistry of the coupling products was researched and the results that decreasing the steric bulkiness of the N-substituents as well as raising the reaction temperature leads to an increase of the erythro-selectivity were observed. The mechanistic origins of this stereoselectivity are also briefly documented. 相似文献
18.
Yasuaki Tokudome Kazuki Nakanishi Kazuyoshi Kanamori Koji Fujita Hirofumi Akamatsu Teiichi Hanada 《Journal of colloid and interface science》2009,338(2):506-513
Detailed nanostructures have been investigated for hierarchically porous alumina aerogels and xerogels prepared from ionic precursors via sol–gel reaction. Starting from AlCl3·6H2O and poly(ethylene oxide) (PEO) dissolved in a H2O/EtOH mixed solvent, monolithic wet gels were synthesized using propylene oxide (PO) as a gelation initiator. Hierarchically porous alumina xerogels and aerogels were obtained after evaporative drying and supercritical drying, respectively. Macroporous structures are formed as a result of phase separation, while interstices between the secondary particles in the micrometer-sized gel skeletons work as mesoporous structures. Alumina xerogels exhibit considerable shrinkage during the evaporative drying process, resulting in relatively small mesopores (from 5.4 to 6.2 nm) regardless of the starting composition. For shrinkage-free alumina aerogels, on the other hand, the median mesopore size changes from 13.9 to 33.1 nm depending on the starting composition; the increases in PEO content and H2O/EtOH volume ratio both contribute to producing smaller mesopores. Small-angle X-ray scattering (SAXS) analysis reveals that variation of median mesopore size can be ascribed to the change in agglomeration state of primary particles. As PEO content and H2O/EtOH ratio increase, secondary particles become small, which results in relatively small mesopores. The results indicate that the agglomeration state of alumina primary particles is influenced by the presence of weakly interacting phase separation inducers such as PEO. 相似文献
19.
20.
Yasuaki KohamaDaiki Motegi 《Experimental Thermal and Fluid Science》1994,8(4):273-278
Boundary layers that develop over a body in fluid flow are in most cases three-dimensional owing to the spin, yaw, or surface curvature of the body. Therefore, the study of three-dimensional (3D) boundary-layer transition is essential to work in practical aerodynamics. The present investigation is concerned with the problem of 3D boundary layers over a yawed body. A yawed cylinder model that represents the leading edge portion of a swept wing and the mechanism of crossflow instability are investigated in detail using hot-wire velocimetry and a flow visualization technique. As a result, traveling disturbances having frequencies f1 and f2, which differ by about one order of magnitude, are detected in the transition region. The phase velocities and directions of travel of those disturbances are measured. Results for the low-frequency disturbance f1 show qualitative coincidence with results numerically predicted for a crossflow unsteady disturbance. Nameley, F1 travels nearly spanwise to the yawed cylinder and very close to the cylinder wall. The results for the high-frequency disturbance f2 good agreement with the existing experimental results. The 2 disturbance is found to be the high-frequency inflectional secondary instability that appears in 3D boundary layer transition in general. A two-stage transition process, where stationary crossflow vortices appear as the primary instability and a traveling inflectional disturbance is generated as a secondary instability, was observed. Secondary instability seems to play a major role in turbulent transition. 相似文献