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111.
Jiye Jin Toshiya Hiroi Kiyohito Sato Tomoo Miwa Toyohide Takeuchi 《Analytical sciences》2002,18(5):549-554
In this study, a wall-jet flow cell with a GRC (graphite reinforced by carbon) electrode was designed for the amperometric detection of phenol and chlorophenols in liquid chromatography. The voltammetric responses of these analytes at the GRC electrodes are very similar to those at conventional glassy carbon electrodes. As the GRC electrodes were made of the same materials as commercially available mechanical pencil leads, they exhibit the advantages of low cost, simple surface renewability, lower residual current, and good electrode-to-electrode reproducibility, and thus can be used as disposable-type electrodes. Chromatographic separations of phenol, o-chlorophenol (o-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) were achieved with an ODS column using a mobile phase containing a mixture of CH3CN and H20 (40:60) containing 25 mM L-(+)tartaric acid (pH = 4.5). Amperometric detections were based on the electrochemical oxidation of these compounds around +0.9 V vs. Ag/AgCl. Under the optimized conditions, linear calibrations were obtained in a range up to 100 microM for phenol, o-CP, 2,4-DCP, 2,4,6-TCP, and 200 microM for PCP, with the correlation coefficients r2 of 0.9992, 0.9997, 0.9986, 0.9992, and 0.9968, respectively. The chromatographic detection limits for the tested analytes were obtained at pmol levels. 相似文献
112.
Noujima A Mitsudome T Mizugaki T Jitsukawa K Kaneda K 《Molecules (Basel, Switzerland)》2011,16(10):8209-8227
We have developed a highly efficient and green catalytic deoxygenation of epoxides to alkenes using gold nanoparticles (NPs) supported on hydrotalcite [HT: Mg(6)Al(2)CO(3)(OH)(16)] (Au/HT) with alcohols, CO/H(2)O or H(2) as the reducing reagent. Various epoxides were selectively converted to the corresponding alkenes. Among the novel metal NPs on HT, Au/HT was found to exhibit outstanding catalytic activity for the deoxygenation reaction. Moreover, Au/HT can be separated from the reaction mixture and reused with retention of its catalytic activity and selectivity. The high catalytic performance of Au/HT was attributed to the selective formation of Au-hydride species by the cooperative effect between Au NPs and HT. 相似文献
114.
115.
Annals of Combinatorics - In this article, we prove a tableau formula for the double Grothendieck polynomials associated to 321-avoiding permutations. The proof is based on the compatibility of the... 相似文献
116.
Tomoo Yokoyama 《Topology and its Applications》2009,156(13):2224-2225
We prove that there is a topology τ that does not arise as a de Groot dual topology such that τd=τddd≠τdd?τ (i.e. the answer for Question 3.9 [M.M. Kovár, At most 4 topologies can arise from iterating the de Groot dual, Topology Appl. 130 (2003) 175-182] is negative). 相似文献
117.
Motokura K Fujita N Mori K Mizugaki T Ebitani K Jitsukawa K Kaneda K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(32):8228-8239
A ruthenium-grafted hydrotalcite (Ru/HT) and hydrotalcite-supported palladium nanoparticles (Pd(nano)/HT) are easily prepared by treating basic layered double hydroxide, hydrotalcite (HT, Mg(6)Al(2)(OH)(16)CO(3)) with aqueous RuCl(3)n H(2)O and K(2)[PdCl(4)] solutions, respectively, using surface impregnation methods. Analysis by means of X-ray diffraction, and energy-dispersive X-ray, electron paramagnetic resonance, and X-ray absorption fine structure spectroscopies proves that a monomeric Ru(IV) species is grafted onto the surface of the HT. Meanwhile, after reduction of a surface-isolated Pd(II) species, highly dispersed Pd nanoclusters with a mean diameter of about 70 A is observed on the Pd(nano)/HT surface by transmission electron microscopy analysis. These hydrotalcite-supported metal catalysts can effectively promote alpha-alkylation reactions of various nitriles with primary alcohols or carbonyl compounds through tandem reactions consisting of metal-catalyzed oxidation and reduction, and an aldol reaction promoted by the base sites of the HT. In these catalytic alpha-alkylations, homogeneous bases are unnecessary and the only by-product is water. Additionally, these catalyst systems are applicable to one-pot syntheses of glutaronitrile derivatives. 相似文献
118.
Hiroshi Fukui Tomoo Katsura Takahiro Kuribayashi Takuya Matsuzaki Akira Yoneda Eiji Ito Yasuhiro Kudoh Satoshi Tsutsui Alfred Q. R. Baron 《Journal of synchrotron radiation》2008,15(6):618-623
Inelastic X‐ray scattering (IXS) measurements have been performed on an MgO single crystal in order to evaluate IXS as a methodology for accurate and precise determination of elastic constants and sound velocities. By performing the IXS experiment using a 12‐analyzer array, the complete set of single‐crystal elastic constants of MgO were determined to a precision better than 0.8% (sound velocities to better than 0.2%). The results are consistent with values in the literature. The precision and accuracy of this work, which is significantly better than other published work to date, demonstrates the potential of IXS in determining elastic properties. 相似文献
119.
Moshe Kuznietz Tomoo YamamuraDexin Li Yoshinobu Shiokawa 《Journal of magnetism and magnetic materials》2008
Rather old preparation of the compounds ThCo2Ge2 and ThCo2Si2 and their magnetic study in the temperature range 100–570 K, published by Omejec and Ban [Z. Anorg. Allg. Chem. 380 (1971) 111], indicated that both compounds ordered ferrromagnetically below 100 K. In order to verify the old data, polycrystalline samples of ThCo2Ge2 and ThCo2Si2 have been prepared by arc melting and subsequent annealing, and studied by X-ray diffraction at room temperature (RT), by superconducting quantum interference device (SQUID)-magnetization and AC-susceptibility measurements at 2–320 K, and by dc-magnetization measurements in variable magnetic fields up to 120 kOe at 5, 80, and 283 K. The magnetic measurements confirm the ferromagnetic ordering in both compounds, but with totally different Curie temperatures: ≈120(20) K for ThCo2Ge2 and above 320 K for ThCo2Si2. The paramagnetic values of ThCo2Ge2 and the ordering of both compounds are discussed and compared with the old results of Omejec and Ban. 相似文献
120.
Photochemical formation of colloidal silver, colloidal gold and silver-gold (Ag-Au) composite colloids under mild conditions has been studied. Irradiation of either aqueous AgCIO4 or HAuCI4 solution in the presence of sodium alginate (SA) with 253.7 nm light yielded colloidal silver or gold, whose particle diamter was 10-30 nm or 40-60 nm, respectively. The Ag-Au composite colloids consisting of mixtures of silver and gold domains (particle diameter 30-150 nm) have been prepared and their extinction spectra have been examined on the basis of a conventional Mie theory in combination with an effective medium theory to estimate the optical constants of these colloids. It has been shown that the extinction spectra of the Ag-Au composite colloids are completely different from those of Ag-Au alloy colloids, in that the former have two extinction maxima close to the colloidal extinction bands of pure silver and gold, in contrast to a single extinction maximum of the latter. The importance of natural, high-molecular carboxylic acids such as alginic acid in the photochemical formation of metal colloids and thin films has been stressed. 相似文献