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排序方式: 共有167条查询结果,搜索用时 31 毫秒
1.
Li-Ngee Ho Tasuku Ikegawa Hiroyasu Nishiguchi Katsutoshi Nagaoka Yusaku Takita 《Applied Surface Science》2006,252(18):6260-6268
A synthesis of molybdenum incorporated mesoporous aluminophosphate with long-chain n-alkylamine as template material had been prepared under non-aqueous condition. These materials were extensively characterized by using X-ray diffraction (XRD), nitrogen sorption isotherms, nuclear magnetic resonance of 27Al and 31P (NMR), inductive coupled plasma (ICP), electron spin resonance (ESR), Fourier transform infrared (FTIR) and thermogravimetric-differential thermal analysis (TG-DTA). Morphology of the materials had been observed by using transmission electron microscope (TEM) that revealed the mesoporous materials possessed wormhole-like structures. Alkaline solvent extraction using n-butylamine/ethanol had been efficiently removed the n-alkylamine from the mesoporous samples which yielded BET surface areas around 550-730 m2/g. BJH analysis showed a narrow pore size distribution which increased with increasing of the carbon chain length of alkylamine (template). Valence state and coordination of the molybdenum in the obtained samples were investigated by using ESR and FTIR where it was found that Mo4+ and Mo6+ molybdenum species existed in the molybdenum incorporated mesoporous aluminophosphate in tetrahedral coordination. 相似文献
2.
Hiroyasu Nishiguchi Hiroshi Yamada Masaru Ogura Tatsumi Ishihara Yusaku Takita 《Research on Chemical Intermediates》2003,29(7-9):755-760
The oxygen storage capacity of CeO2, Ce0.9Pr0.1O2, Pt?Rh/CeO2 and Pt?Rh/Ce0.9Pr0.1O2 was investigated by conventional GC pulse method and transient pulse techniques. It is shown that incorporation of PrOy into CeO2 matrix strongly promotes oxygen storage capacity (OSC) measured using the transient pulse technique. The improvement of OSC at low temperature is observed in Pt?Rh loaded onto CeO2 and Ce?Pr catalysts. 相似文献
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Light emission and scattering are analyzed for the plume of vapor produced by laser excitation of the solid target of Group II, III and IV elements. Spectroscopic evidences suggest that the plume consists of microclusters of target elements. The size of microclusters is estimated to be 0.6 nm in diameter. 相似文献
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Dr. Yusaku Nomura Dr. Frédéric Thuaud Dr. Daisuke Sekine Prof. Dr. Akihiro Ito Satoko Maeda Dr. Hiroyuki Koshino Dr. Daisuke Hashizume Dr. Atsuya Muranaka Dr. Thomas Cruchter Prof. Dr. Masanobu Uchiyama Prof. Dr. Satoshi Ichikawa Prof. Dr. Akira Matsuda Prof. Dr. Minoru Yoshida Prof. Dr. Go Hirai Prof. Dr. Mikiko Sodeoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(35):8387-8392
A synthetic methodology to access all possible stereoisomers of spectomycin A1 (SMA1) and A2 (SMA2) has been established through late-stage diversification. The key reaction for the construction of all four diastereomers is an intramolecular cyclization based on the umpolung of π-allyl palladium species with bis(pinacolato)diborane (B2(pin)2). Silyl group assisted direct benzylic oxidation of each isomer enabled construction of the fragile β-hydroxytetralone skeleton to provide the SMAs. The relative and absolute stereochemistry of SMA2 was also determined, and the absolute stereochemistry of SMA1 was extrapolated based on the optical rotation of SMA2. The axial chirality of SMAs is discussed based on circular dichroism spectra and DFT calculations, and it is concluded that the M isomer is predominant in solution. Biochemical assessment of all isomers in vitro revealed that the C9 hydroxyl group and dimeric structure were both important for protein SUMOylation-inhibitory activity. 相似文献
7.
Tomohiro Sakata Shingo Ogawa Keiko Inoue Yumiko Shimizu Yusaku Tanahashi 《Surface and interface analysis : SIA》2022,54(6):661-666
To systematically evaluate the quality of SiNx films in multi-stacked structures, we investigated the effects of post-deposition annealing (PDA) on the film properties of SiNx within the SiO2/SiNx/SiO2/Si stacked structure by performing X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), Fourier transform infrared (FT-IR) spectroscopy, and scanning transmission electron microscope–electron energy loss spectroscopy (STEM-EELS) analyses. The XPS results showed that PDA induces the oxidation of the SiNx layer. In particular, new finding is that Si-rich SiNx in the SiNx layer is preferentially oxidized by PDA even in multi-stacked structure. The XRR results showed that the SiNx layer becomes thinner, whereas the interface layer between the SiNx layer and Si becomes thicker. It is concluded by STEM-EELS and XPS that this interface layer is SiON layer. The density of N–H and Si–H bonding within the stacked structure strongly depends on the PDA temperature. Our study helps elucidate the properties of SiNx films in stacked structures from various perspectives. 相似文献
8.
The resonant Raman scattering of polar optical phonons has been measured in trigonal γ-InSe at the E'1 exciton edge. The two-phonon scattering spectrum widely spreads over the frequency range of 50 cm-1 with an extremely asymmetric lineshape. This spectrum has been interpreted in terms of the directional dispersion of extraordinary LO and TO phonons. 相似文献
9.
Yusaku Iwasawa Tetsuroh Shirasawa Takehiro Nojima Toshio Takahashi Masuaki Matsumoto Koichi Akimoto Hiroshi Sugiyama 《Applied Surface Science》2008,254(23):7803-7806
The structure of buried Si(1 1 1)-5 × 2-Au capped with amorphous Si was investigated using surface X-ray diffraction. It was found that the 5 × 2 structural periodicity is kept under the amorphous Si from the in-plane measurement. Furthermore, the intensity variation along the fractional-order rod indicates that Au atoms are located almost on the same plane. 相似文献
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