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Hydrothermal formation of tobermorite studied by in situ X‐ray diffraction under autoclave condition
Jun Kikuma Masamichi Tsunashima Tetsuji Ishikawa Shin‐ya Matsuno Akihiro Ogawa Kunio Matsui Masugu Sato 《Journal of synchrotron radiation》2009,16(5):683-686
Hydrothermal formation of tobermorite from a pre‐cured cake has been investigated by transmission X‐ray diffraction (XRD) using high‐energy X‐rays from a synchrotron radiation source in combination with a newly designed autoclave cell. The autoclave cell has a large and thin beryllium window for wide‐angle X‐ray diffraction; nevertheless, it withstands a steam pressure of more than 1.2 MPa, which enables in situ XRD measurements in a temperature range of 373 to 463 K under a saturated steam pressure. Formation and/or decomposition of several components has been successfully observed during 7.5 h of reaction time. From the intensity changes of the intermediate materials, namely non‐crystalline C–S–H and hydroxylellestadite, two pathways for tobermorite formation have been confirmed. Thus, the newly developed autoclave cell can be used for the analyses of reaction mechanisms under specific atmospheres and temperatures. 相似文献
74.
9,10‐Diaminoanthracenes Revisited: The Influence of N‐Substituents on Their Electronic States
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Masashi Uebe Prof. Dr. Tatsuhisa Kato Prof. Dr. Kazuyoshi Tanaka Dr. Akihiro Ito 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(52):18923-18931
The electronic and molecular structures of 9,10‐diamino‐substituted anthracenes with different N‐substituents have been re‐examined. In particular, different N‐substituents influence both the electronic and molecular structures of the oxidized species of 9,10‐diaminoanthracenes. The anthrylene moiety of 9,10‐bis(N,N‐di(p‐anisyl)amino)anthracene retains its planarity during the course of two successive one‐electron oxidations, whereas 9,10‐bis(N,N‐dimethylamino)anthracene and 9,10‐bis(N‐p‐anisyl‐N‐methylamino)anthracene undergo a substantial structural change to a butterfly‐like structure through a two‐electron oxidation process. The structural changes observed for the oxidized states are ascribed to significant differences in the frontier molecular orbitals of the above‐mentioned three kinds of 9,10‐diaminoanthracenes due to different extents of mixing between the amine‐localized and anthrylene‐localized orbitals. 相似文献
75.
Porphyrin accumulation onto a self-assembled monolayer (SAM) of imidazole-substituted porphyrins by a supramolecular method to form a chain structure leads to significant increase of light absorption in the visible light region and therefore photocurrents. 相似文献
76.
In view of recent developments in the investigation on cuprate high- T(c) superconductors and the spin-Peierls compound CuGeO3, we study the effect of dilute impurity doping on the spin-Peierls state in quasi-one-dimensional systems. We identify a common origin for the emergence of antiferromagnetic order upon the introduction of static vacancies and superconductivity for mobile holes. 相似文献
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Hiroshi Tanaka Takeo Yoshioka Yasutaka Shimauchi Akihiro Yoshimoto Tomoyuki Ishikura Hiroshi Naganawa Tomio Takeuchi Hamao Umezawa 《Tetrahedron letters》1984,25(31):3351-3354
The tricyclic quinone 8 was successfully synthesized from naphthazalin, and the total synthesis of (±)-2-hydroxyaklavinone via 8 was accomplished in an overall yield of about 18% through the regio-controlled route. 相似文献
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Mayumi Tsutsui Tokuhiro Watanabe Akihiro Ohta Kayoko Takizawa 《Journal of heterocyclic chemistry》1980,17(4):809-812
1 H-Nmr spectra of cis and trans isomers of 2,3-, 2,5-, and 2,6-dimethylpiperazines were taken at various temperatures. The spectra of geometrical isomers bearing the ae or ea dimethyl groups showed broadening at lower temperatures. It was clarified that the measurement of the spectra at lower temperatures is useful for the discrimination of the geometrical isomers of dimethylpiperazines. 相似文献