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81.
Naonobu Tanaka Yuyu Jia Kanji Niwa Kiyoshi Imabayashi Yutaka Tatano Hideki Yagi Yoshiki Kashiwada 《Tetrahedron》2018,74(1):117-123
Seven new phloroglucinol derivatives, myrtucommunins A–D (1–4), 6-methylisomyrtucommulone B (5), 4-methylmyrtucommulone B (6), and 2-isobutyryl-4-methylphloroglucinol 1-O-β-d-glucopyranoside (7), and one new chromone derivative, undulatoside A 6′-O-gallate (8), were isolated from the leaves of Myrtus communis (Myrtaceae). Myrtucommunins A–D (1–4) were conjugates of polymethylated acylphloroglucinol and flavonol rhamnoside. The absolute configurations of the rhamnosyl moieties for 1–4 were confirmed to be l in each case by HPLC analyses, while those of the aglycones were assigned by comparisons of the experimental and TDDFT calculated ECD spectra. 6-Methylisomyrtucommulone B (5) and 4-methylmyrtucommulone B (6) were assigned as 6/6/6 tricyclic acylphloroglucinol derivatives with a racemic nature. Antimicrobial activities of 1–8 and related known compounds were evaluated. 相似文献
82.
A. A. Kaminskii M. Sh. Akchurin R. V. Gainutdinov K. Takaichi A. Shirakava H. Yagi T. Yanagitani K. Ueda 《Crystallography Reports》2005,50(5):869-873
The microhardness and fracture toughness of laser nanocrystalline ceramics based on the cubic oxides Y2O3 and Y3Al5O12 are determined experimentally. It is shown by comparative measurements that the fracture toughness and microhardness of Y2O3 ceramics exceed the corresponding parameters of Y2O3 single crystals by factors of 2.5 and 1.3, respectively. The fine morphology of grains and grain boundaries in fractures is investigated. It is ascertained that changes in the mechanical properties of the nanocrystalline ceramics under study are related to both the sizes and structure of grains and the structure of grain boundaries. It is suggested that twinning processes determine the mechanisms of formation of nanocrystalline ceramics. 相似文献
83.
A. A. Kaminskii K. Ueda A. F. Konstantinova H. Yagi T. Yanagitani A. V. Butashin V. P. Orekhova J. Lu K. Takaichi T. Uematsu M. Musha A. Shirokava 《Crystallography Reports》2003,48(5):868-871
Refractive indices of the nanocrystalline Y3Al5O12 ceramic and a garnet single crystal of the same composition have been measured. In the visible and near IR range (0.4–1.064 μm), the prism method was used; in the medium IR range (2–6.2 μm), the interference method with the use of thin plates was applied. The refractive indices of these crystalline materials are practically the same over the entire spectral range studied and are described by the approximate formula proposed earlier for a single crystal. The parameters of the continuos-wave lasing in the nanocrystalline Y3Al5O12 ceramic doped with Nd3+ and Yb3+ ions measured recently are presented. 相似文献
84.
A quasi-degenerate perturbation method with vibrational self-consistent field (VSCF) reference wavefunction is developed. It simultaneously accounts for strong anharmonic mode-mode coupling among a few states (static correlation) by a configuration interaction theory and for weak coupling with a vast number of the other states (dynamic correlation) by a perturbation theory. A general formula is derived based on the van Vleck perturbation theory. An algorithm that selects a compact set of the most important VSCF configurations which contribute to the static correlation is proposed and a scheme to limit the number of configurations considered for dynamic correlation is also implemented. This method reproduces the vibrational frequencies of CO2 and H2CO that are subject to the strongest anharmonic mode-mode coupling within 10 cm(-1) of vibrational configuration interaction results in a computational expense reduced by a factor of one to two orders of magnitude. The method also reproduces the infrared absorption of C6H6 in the CH stretching (nu12) frequency region, in which combination tones nu13nu16 and nu2nu13nu18 appear on account of an intensity borrowing from nu12via the anharmonic coupling. 相似文献
85.
Kanaoka S Yagi N Fukuyama Y Aoshima S Tsunoyama H Tsukuda T Sakurai H 《Journal of the American Chemical Society》2007,129(40):12060-12061
86.
A fast algorithm of vibrational second-order Moller-Plesset perturbation theory is proposed, enabling a substantial reduction in the number of vibrational self-consistent-field (VSCF) configurations that need to be summed in the calculations. Important configurations are identified a priori by assuming that a reference VSCF wave function is approximated well by harmonic oscillator wave functions and that fifth- and higher-order anharmonicities are negligible. The proposed scheme has reduced the number of VSCF configurations by more than 100 times for formaldehyde, ethylene, and furazan with an error in computed frequencies being not more than a few cm(-1). 相似文献
87.
J. Lu M. Prabhu J. Song C. Li J. Xu K. Ueda A.A. Kaminskii H. Yagi T. Yanagitani 《Applied physics. B, Lasers and optics》2000,71(4):469-473
Optical absorption, emission spectra have been measured for polycrystalline Nd-doped Y3Al5O12 ceramics. Fluorescence lifetimes of 257.6 μs, 237.6 μs, 184.2 μs and 95.6 μs have been obtained for 0.6%, 1%, 2% and 4% neodymium-doped
YAG ceramics, respectively. For the first time, highly efficient laser oscillation at 1064 nm has been obtained with this
kind of ceramics. Slope efficiency of 53% has been achieved on a uncoated 4.8-mm thick 1% Nd:YAG ceramics sample. Optical
to optical conversion efficiency is 47.6%. Laser oscillation has also been obtained with a 2% Nd:YAG ceramics. The optical
properties and laser output results have been compared with that of Nd:YAG single crystal grown by the Czochralski method.
Almost identical results have been achieved including laser experiments results. But fabrication of Nd:YAG ceramics is much
easier compared to the single-crystal growth method. And also large size (now of about 400 mm diameter×5 mm is available)
and high-concentration (>1%) Nd:YAG ceramics can be fabricated. The results show that this kind of Nd:YAG ceramics is a very
good alternative to Nd:YAG single crystal.
Received: 20 April 2000 / Published online: 16 August 2000 相似文献
88.
Takayuki Muro Yukako Kato Toyohiko Kinoshita Yoshio Watanabe 《Journal of synchrotron radiation》2009,16(4):595-596
A video camera system for observing a sample from the direction of an incident soft X‐ray beam has been developed. The sample is seen via two reflecting mirrors. The first mirror, which has a hole to allow the soft X‐ray beam to pass through, is set on the beam axis in a vacuum. The second mirror is used to cancel out the mirror inversion of the image. This camera system is used for efficient positioning of samples in a soft X‐ray beam. 相似文献
89.
A [Ru(bpy)(3)](2+) (bpy=2,2'-bipyridine)-doped WO(3) film was prepared as a base layer on a substrate by cathodic electrodeposition from a colloidal triad solution containing peroxotungstic acid (PTA), [Ru(bpy)(3)](2+), and poly(sodium 4-styrenesulfonate) (PSS). A Prussian blue (PB; Fe(II)-Fe(III)) film was cathodically electrodeposited on the [Ru(bpy)(3)](2+)-doped WO(3) film or neat WO(3) film from an aqueous Berlin brown (BB; Fe(III)-Fe(III)) colloid solution to yield a [Ru(bpy)(3)](2+)-doped WO(3)/PB bilayer film or WO(3)/PB bilayer film. For the spectrocyclic voltammogram (SCV) of the WO(3)/PB film, a redox response of Prussian white (PW; Fe(II)-Fe(II))/PB was observed at 0.11 V, however, further oxidation of PB to BB was not allowed by the interfacial n-type Schottky barrier between the WO(3) and PB layers. For the [Ru(bpy)(3)](2+)-doped WO(3)/PB film, any electrochemical response assigned to the redox of PB was not observed in the cyclic voltammogram, however, the in situ absorption spectral change recorded simultaneously showed the significant redox reactions based on PB. The SCV revealed that PW on the [Ru(bpy)(3)](2+)-doped WO(3) film is completely oxidized to PB by a geared reaction of Ru(II)/Ru(III) at 1.05 V, and that 32 % of PB formed is further oxidized to BB by the same geared reaction in the potential scan to 1.5 V. PB was completely re-reduced to PW by a geared reaction of H(x)WO(3)/WO(3) at -0.5 V in the reductive potential scan. These geared electrochemical reactions produced an electrochromic hysteresis performance of the PB film layered on the [Ru(bpy)(3)](2+)-doped WO(3) film. 相似文献
90.
A flow-based enzyme-linked immunosorbent assay (ELISA) on a polydimethylsiloxane (PDMS) microchip has been developed for the rapid determination of immunoglobulin A (IgA). The analytical principle of this integrated method is the same as the conventional sandwich-type ELISA. A primary antibody (anti-IgA) was adsorbed on the surface of a PDMS microchannel, and then an antigen (IgA) and a secondary antibody (anti-IgA HRP labeled) were reacted successively. The resulting antigen-antibody complex, fixed on the surface of the microchannel, was detected using Amplex® Red and a fluorescent imaging system. The calibration curve of the IgA standard solution was linear in the range of 0-50 ng/mL at the flow rate of 10 μL/min. This flow rate corresponds to the reaction time of 4.8 s. Compared to the conventional assay on a 96-well microtiter plate, the present assay on the microchip dramatically shortened the reaction time necessary for the enzyme-substrate reaction from 30 min to 4.8 s, i.e., to 1/375. The amounts of the reagent and sample were also reduced to 1/100 compared to the 96-well microtiter plate. 相似文献