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91.
Kenji Yoshii Naoshi Ikeda Yusuke Yokota Yasuhiro Yoneda Yoichi Horibe 《Journal of solid state chemistry》2009,182(7):1611-1618
We have investigated the magnetic and dielectric properties of YbFe2−xMnxO4 (0?x?1), which is an Fe-site-substituted system of new multiferroic oxides RFe2O4 (R=Y, Ho-Lu). X-ray diffraction measurements show that a solid solution is formed between YbFe2O4 (x=0) and YbFeMnO4 (x=1) for 0?x?1, whereas only compounds with x=1 (i.e., RM1M2O4; M1 and M2=trivalent and divalent cations, respectively) have been known for the Fe-site substitution in RFe2O4. The valence of the Mn ion is determined to be ∼2+, consistently with the suppression of low-temperature magnetization by the Mn substitution. The magnetic transition temperature (TN) and the dielectric constant (ε′) decrease monotonically with increasing x. This result plausibly confirms that the magnetic and dielectric properties in oxides isostructural with RFe2O4 are governed by the electron transfer between Fe-site ions, unlike ordinary ferroelectrics and dielectrics, in which the ionic displacement plays a key role. The possibility for application is briefly discussed as well. 相似文献
92.
A highly efficient synthesis of a tetracyclic intermediate
to the antitumor antibiotics AX-2
, mitomycin A
, and C
is described. 相似文献
93.
In this paper we prove that a morphism between schemes or stacks naturally corresponds to a symmetric monoidal functor between stable $\infty $ -categories of quasi-coherent complexes. It can be viewed as a derived analogue of Tannaka duality. As a consequence, we deduce that an algebraic stack satisfying a certain condition can be recovered from the symmetric monoidal stable $\infty $ -category of quasi-coherent complexes with tensor operation. 相似文献
94.
Dr. Yoichi M. A. Yamada Toshihiro Watanabe Tomohiko Beppu Naoshi Fukuyama Kaoru Torii Prof. Dr. Yasuhiro Uozumi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(37):11311-11319
Instantaneous catalytic carbon–carbon bond‐forming reactions were achieved in catalytic membrane‐installed microchannel devices that have a polymeric palladium‐complex membrane. The catalytic membrane‐installed microchannel devices were provided inside the microchannels by means of coordinative and ionic molecular convolution at the interface between the organic and aqueous phases flowing laminarly, in which both non‐crosslinked linear polymer ligands and palladium species dissolved. The palladium‐catalyzed Suzuki–Miyaura reaction of aryl, heteroaryl, and alkenyl halides with arylboronic acids and sodium tetraarylborates was performed with the catalytic membrane‐installed microchannel devices to give quantitative yields of biaryls, heterobiaryls, and aryl alkenes within 5 s of residence time in the defined channel region. These microchannel devices were applied to the instantaneous allylic arylation reaction of allylic esters with arylboron reagents under microflow conditions to afford the corresponding coupling products within 1 s of residence time. 相似文献
95.
Revisiting the Bromination of CH Bonds with Molecular Bromine by Using a Photo‐Microflow System
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Dr. Yoshiyuki Manabe Yuriko Kitawaki Masahiro Nagasaki Prof. Koichi Fukase Prof. Hiroshi Matsubara Yoshiko Hino Prof. Takahide Fukuyama Prof. Ilhyong Ryu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12750-12753
The photobromination of C?H bonds by using molecular bromine was reinvestigated under microfluidic conditions. The continuous‐flow method suppressed the production of dibrominated compounds and effectively produced the desired monobrominated products with high selectivity. Rapid bromination of benzylic substrates containing a photoaffinity azide group was achieved without any decomposition. 相似文献
96.
97.
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99.
C. Funayama T. Furukawa T. Sato Y. Ichikawa Y. Ohtomo Y. Sakamoto S. Kojima T. Suzuki C. Hirao M. Chikamori E. Hikota M. Tsuchiya A. Yoshimi C. P. Bidinosti T. Ino H. Ueno Y. Matsuo T. Fukuyama K. Asahi 《Hyperfine Interactions》2015,232(1-3):59-66
We demonstrate spin-exchange optical pumping of 129Xe atoms with our newly made laser system. The new laser system was prepared to provide higher laser power required for the stable operation of spin maser oscillations in the 129Xe EDM experiment. We studied the optimum cell temperature and pumping laser power to improve the degree of 129Xe spin polarization. The best performance was achieved at the cell temperature of 100 °C with the presently available laser power of 1 W. The results show that a more intense laser is required for further improvement of the spin polarization at higher cell temperatures in our experiment. 相似文献
100.
Harada Y Takeuchi T Kino H Fukushima A Takakura K Hieda K Nakao A Shin S Fukuyama H 《The journal of physical chemistry. A》2006,110(49):13227-13231
The electronic structures of a series of DNA nucleobases and their dinucleotides were investigated by N 1s X-ray absorption, X-ray photoemission, and resonant X-ray emission spectroscopy. Resonant X-ray emission spectra of the guanine base and its dinucleotide indicate that it has a weak structure at the lowest binding energy; at this energy, it isolates from the main valence band and forms the HOMO state. This indicates that the HOMO state is localized in the guanine base, as claimed by valence and core photoemissions and expected from theoretical predictions. In addition, the XAS and XES profiles of the guanine dinucleotide indicate that disruption of the aromatic character of the six-membered ring results in the localization of the pi state at the imine (-N=) site of the guanine base; this may favor charge transfer among stacked guanine bases and further influence the conductivity of DNA. 相似文献