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941.
Ab initio cluster quantum chemical calculations at the Hartree–Fock (HF/Lanl2dz) and correlated second-order Moller–Plesset perturbation theory (MP2/Lanl2dz) levels were performed for NO and N2O interactions with Ag+ and Cu+ ion-exchanged zeolites. The interaction energies were estimated in a conventional way and also corrected for basis set superposition errors. It was shown that the highly dispersed Ag+ counterions establish twofold coordination to the lattice oxygens on the zeolite surface, similar to the case of Cu+ ions. However, both NO and N2O bind relatively strongly to the Cu active sites of Cu+ ion-exchanged zeolites than those of the Ag+ site of the Ag+ ion-exchanged zeolites. Based on the results of these calculations, the two different forms of adsorption for these molecules on the catalyst surface, the nature of their binding and characteristics of the adsorption properties have been discussed. Finally, some comparisons with the results obtained by a variety of density functional theory calculations on target systems have been presented. 相似文献
942.
Ion-exchange absorptiometry combined with flow analysis has been applied to the determination of trace amounts of molybdenum(VI) in natural water and rock. By using a pretreatment column packed with Sephadex G-25 gel, molybdenum(VI) in a sample solution can be sorbed selectively on the gel at pH 3.5. The molybdenum(VI) in the column was desorbed with EDTA as the molybdenum(VI)-EDTA complex, and the solution was introduced into a Tiron solution stream. The yellow complex formed between molybdenum(VI) and Tiron in the flow system was then concentrated on a QAE-Sephadex A-25 anion exchanger packed in a flow-through silica micro-cell. The attenuation of incident light by the molybdenum(VI)-Tiron complex on the anion exchanger in the cell was continuously recorded with a spectrophotometer at 410 nm. The complex on the anion exchanger was easily desorbed with sodium nitrate, so the flow-through cell could be used repeatedly. The minimum amount that could be detected corresponded to 15 ng of molybdenum(VI). Molybdenum(VI) in three or four sample solutions could be determined within 1 h. 相似文献
943.
We present numrical results on the velocity autocorrelation function (VACF)C(t)=<ν(t)·ν(0)> for the periodic Lorentz gas on a two-dimensional triangular lattice as a function of the radiusR of the hard disk scatterers on the lattice. Our results for the unbounded horizon case
confirm 1/t decay of the VACF for long times (out to 100 times the mean free time between collisions) and provide strong support for
the conjecture by Friedman and Martin that the 1/t decay is due to long free paths along which a moving particle does not scatter up to timet. Even after new sets of long free paths become available forR<1/4, we continue to find good agreement between numerical results and an analytically estimated 1/t decay. For the bounded horizon case
, our numerical VACFs decay exponentially, although it is difficult to discriminate among pure exponential decay, exponential
decay with prefactor, and stretched exponential decay. 相似文献
944.
T. Morikawa H. Inoue Y. Iwata T. Matsuoka Y. Yoshizawa T. Kato S. Mitarai J. Mukai D. Jerrestam 《Zeitschrift für Physik A Hadrons and Nuclei》1992,343(3):373-374
The deformed nucleus154Sm was studied by Coulomb excitation with NORDBALL by using a58Ni beam. The ground-state band, the beta band, the gamma band and the octupole band (K=0-) were excited up to the 16+ state, the 6+ state, the 6+ state and the 13-state, respectively. A new band was established from 6+ to 14+ on the basis of the gamma-gamma coincidence spectra. The excitation probability of the new band is larger than that of the beta band.We would like to thank Dr. G. Sletten, Mr. J. Westergaard and the members of TAL, Niels Bohr Institute for their kind support. A part of this research is supported by Monbusho International Scientific Research Program (Joint Research No.01044037). 相似文献
945.
Hideyuki Kaneko Junji Saito Nobuo Kawahara Shingo Matsuo Tomoaki Matsugi Norio Kashiwa 《Journal of polymer science. Part A, Polymer chemistry》2009,47(3):812-823
A new method to prepare the polypropylene (PP) macroinitiator for controlled radical polymerization was described. Bromination of terminally-unsaturated PP was carried out by using N-bromosuccinimide and 2,2′-azobis(isobutyronitrile) to give a brominated PP (PP-Br), that has allylic bromide moieties at or near the chain ends. Thus, the obtained PP-Br was successfully used as a macroinitiator for radical polymerization of styrene, methyl methacrylate, and n-butyl acrylate using a copper catalyst system. From 1H NMR analysis, it was confirmed that the chain extension polymerization was certainly initiated from allylic bromide moieties with high efficiency, leading to the PP-based block copolymers linking the polar segment. From differential scanning calorimetry, it was observed that peak melting temperature of block copolymers was higher than that of PP-Br and the obtained PP-PS block copolymers with different compositions of each segment demonstrated the unique morphological features due to the microphase separation between both segments. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 812–823, 2009 相似文献
946.
947.
Manabu Tanaka Shingo Imai Takashi Tanii Yoshiteru Numao Naonobu Shimamoto Iwao Ohdomari Hiroyuki Nishide 《Journal of polymer science. Part A, Polymer chemistry》2007,45(3):521-530
A magnetically active, purely organic dot array was formed by the selective deposition of polyradical nanoparticles on array‐like‐formed pits on a silicon substrate. The nanometer‐sized polyradical particles, poly(4‐methacryoyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl), were prepared by the emulsion polymerization of 4‐methacryloyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐acetoxyl followed by a deprotection reaction and oxidation in air. The size (diameter) and radical spin concentration of the polyradical nanoparticles were tunable between the polymerization and oxidation conditions. Electrochemical studies revealed the redox property of the polyradical nanoparticles. The magnetic response image of the polyradical nanoparticles was obtained by magnetic force microscopy, reflecting their radical spin concentrations. These results suggested a possible approach for the use of organic polyradical nanoparticles as organic magnetic dot arrays. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 521–530, 2007 相似文献
948.
949.
M. Matsuoka S. Higashimoto H. Yamashita M. Anpo 《Research on Chemical Intermediates》2000,26(1):85-92
The in-situ characterization of the vanadium silicalite-1 catalyst (VS-1) by means of photoluminescence, ESR and XAFS investigative techniques revealed that this catalyst includes highly dispersed V-O moieties having a tetrahedral coordination in C3v symmetry with one short V=O bond (1.63Å) and three long V-O bonds (1.73Å). The photocatalytic decomposition reaction of NO into N2 was found to proceed much more efficiently in the presence of propane than without. A dynamic quenching study of the photoluminescence spectrum of the VS-1 catalyst by the addition of NO and propane indicates that the excited state of the V-O moieties plays a significant role in this photocatalytic reaction. 相似文献
950.