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991.
Seiichi Sato Takatoshi Ikeda Kengo Hamada Keisaku Kimura 《Solid State Communications》2009,149(21-22):862-865
A germanium (Ge) nanoparticle surface was etched in an aqueous solution under monochromatic light irradiation in the infrared-to-ultraviolet region. Since the bandgap widened up to the photon energy of the irradiating light, the average size of the nanoparticles was controlled and the size distribution narrowed. The quantum size effect explained the correlation between the resulting bandgap energy and the final size. The etched nanoparticles showed blue-green or red-infrared photoluminescence (PL) after the surfaces were terminated with organic molecules or hydrogen atoms. The PL peak energy was independent of size, indicating PL was due to radiative recombination via localized states at the Ge core surface. 相似文献
992.
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
993.
Tomoko Matsuda Kazuro Ikawa Kayo Ikeda Norifumi Morikawa Ryu Tsumura Masaaki Shibukawa Koji Iida Kaoru Kurisu 《Chromatographia》2009,69(9-10):1031-1034
A simple, rapid and accurate liquid chromatography method using ultrafiltration to pretreat cerebrospinal fluid (CSF) samples was developed to determine meropenem concentrations in human CSF in clinical settings. Meropenem in CSF samples was stabilized by mixing with 1 mol L?1 3-morpholinopropanesulfonic acid buffer (pH 7.0) (1:1). The mixture was transferred to a Nanosep 10 K centrifugal filter device; after centrifugation, the filtrate was subjected to reversed-phase LC and the eluate was monitored at 300 nm. The retention time for meropenem was 5.8 min. The calibration curve of meropenem in human CSF was linear over 0.05–50 μg mL?1. The intra-day and inter-day precision was 0.27–5.66 % and accuracy was 99.0–109.5 %. The limit of detection was 0.01 μg mL?1. This method was successfully applied to neurosurgical patients, showing that it is applicable for therapeutic drug monitoring in patients receiving meropenem. 相似文献
994.
Reaction efficiencies of two organic alkalis, tetramethylammonium hydroxide (TMAH) and trimethylsulfonium hydroxide (TMSH), with lipids during thermally assisted hydrolysis and methylation (THM) were examined focusing on (1) the types of lipids and (2) degree of unsaturation of fatty acid moieties. Different types of lipids such as triglycerides, phospholipids, free fatty acids and cholesteryl esters containing saturated, monounsaturated or polyunsaturated fatty acid (PUFA) residues were subjected to THM-gas chromatography (GC) in the presence of TMAH or TMSH. The obtained results revealed that the THM reaction using TMAH allowed almost quantitative methylation of saturated and monounsaturated fatty acid components independently of the classes of lipids. However, strong alkalinity of TMAH brought about isomerization and/or degradation of PUFA components. In contrast, the use of TMSH was effective to highly sensitive detection of PUFA as well as saturated and monounsaturated fatty acid components contained in triglycerides, phospholipids (phosphatidylcholines) and free fatty acids. On the other hand, TMSH was proved to react hardly with any kind of fatty acid residues in cholesteryl esters due to their steric hindrance. 相似文献
995.
Ishaq A. Zaafarany Khalid S. Khairou Refat M. Hassan Yasuhisa Ikeda 《Arabian Journal of Chemistry》2009,2(1):1-6
The electrical conductivity of cross-linked thorium(IV)–alginate complex in the form of circular disc has been investigated as a function of temperature. The Arrhenius plot of log σ vs. 1/T showed a simple parabolic shape at the early stages, followed by a sharply increase in o values with raising the temperature at the final stages. This behaviour was interpreted by the formation of free-radicals at the initial stages, followed by the degradation of the complex at elevated temperatures to give rise to thorium oxide product. The heterogeneous chemical equilibrium for exchange of Th4+ counter ions in the complex by H+ ions has been investigated by titrimetric and complexometric techniques. The thermodynamic equilibrium constant was found to be 26 ± 0.25 dm9 mol?3 at 25 °C. The X-ray diffraction pattern indicated that thorium(IV)–alginate complex is amorphous in nature. Infrared absorption spectra indicated that Th4+ is chelated to alginate macromolecular chains and displayed υs OCO? and υas OCO? in the ranges of 1419 and 1635 cm?1, respectively. A geometrical structure for chelation of thorium(IV) to the functional groups of alginate macromolecule is suggested and discussed in terms of complex stability. 相似文献
996.
Shin Aoki Prof. Yumiko Tomiyama Yoshiyuki Kageyama Dr. Yasuyuki Yamada Dr. Motoo Shiro Dr. Eiichi Kimura Prof. 《化学:亚洲杂志》2009,4(4):561-573
Conditional cleavage : Photochemical S? N bond cleavage of the Zn2+ complex of N‐dansylcyclen (ZnL2) in aqueous solution was investigated. Moreover, photolysis of ZnL2 (see scheme) facilitated photoreversion of cis,syn‐thymine photodimer (T[c,s]T).
997.
Yusuke Ohba Mayuko Takatsuji Kenji Nakahara Hiromichi Fujioka Dr. Yasuyuki Kita Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(14):3526-3537
Facile and efficient macrolactonization of hydroxycarboxylic acid via ethoxyvinyl esters (EVEs), which can give 9‐ to 14‐membered macrolactones in good yields, has been developed (see scheme; DCE = 1,2‐dichloroethane). The method is useful for acid‐/base‐sensitive substrates and applicable to the compound with many functional groups.
998.
Taichi Ikeda Dr. Masayoshi Higuchi Dr. Dirk G. Kurth Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(19):4906-4913
Towards polythiophene polyrotaxanes : The β‐substituted terthiophene [2]rotaxanes have been synthesized (see figure). Basic optical and electrochemical properties of the synthesized [2]rotaxanes are also reported.
999.
We study the behavior of the quarter-filled Kondo-lattice model on a triangular lattice by combining a zero-temperature variational approach and finite-temperature Monte Carlo simulations. For intermediate coupling between itinerant electrons and classical moments S(j), we find a thermodynamic phase transition into an exotic spin ordering with uniform scalar spin chirality and (S(j))=0. The state exhibits a spontaneous quantum Hall effect. We also study how its properties are affected by the application of an external magnetic field. 相似文献
1000.
Using Hilbert phase microscopy for extracting quantitative phase images, we measured the average refractive index associated with live cells in culture. To decouple the contributions to the phase signal from the cell refractive index and thickness, we confined the cells in microchannels. The results are confirmed by comparison with measurements of spherical cells in suspension. 相似文献