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91.
Sugawara S Yoshikawa T Takayanagi T Shiga M Tachikawa M 《The journal of physical chemistry. A》2011,115(42):11486-11494
We have carried out path-integral molecular dynamics simulations for hydrated sulfuric acid clusters to understand acid-dissociation and hydrogen-bonded structural rearrangement processes in these clusters from a quantum mechanical viewpoint. The simulations were performed using the PM6 semiempirical electronic structure level whose parameters were modified on the basis of the specific reaction parameters strategy so that relative energies of optimized structures, as well as water binding energies reproduce ab initio and density-functional theory calculations. We have found that the acid dissociation processes, first and second deprotonation, effectively occur in a hydrated cluster with a specific cluster size. The mechanisms of the proton-transfer processes were analyzed in detail and it was found that the distance between O in sulfuric acid and O in the proton-accepting water is playing an important role. We also found that the water coordination number of the poton-accepting water is important in the proton-transfer processes. 相似文献
92.
Yoshida H Ito Y Yoshikawa Y Ohshita J Takaki K 《Chemical communications (Cambridge, England)》2011,47(30):8664-8666
Trifluoromethyl ketones were found to be coupled with arynes in three modes depending upon their substitution patterns, namely C-C bond cleavage, [2+2] cycloaddition and O-arylation. 相似文献
93.
T. Ohshima A. Uedono K. Abe H. Itoh Y. Aoki M. Yoshikawa S. Tanigawa I. Nashiyama 《Applied Physics A: Materials Science & Processing》1998,67(4):407-412
Received: 18 February 1998/Accepted: 5 June 1998 相似文献
94.
Yoshiro Tatsu Soichiro Yamamura Hitoshi Yamamoto Susumu Yoshikawa 《Fresenius' Journal of Analytical Chemistry》1995,351(8):782-785
The fluorescence intensity of 5(6)-carboxyfluorescein (CF) was decreased by addition of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). The reaction inside a liposome containing CF and HRP on addition of H2O2 was measured fluorometrically after destruction of the liposome with Triton X-100. The reaction efficiency was higher than that without liposome because CF and HRP were concentrated inside the latter. The determination of H2O2 can be performed with a smaller amount of HRP by liposome encapsulation. 相似文献
95.
96.
H. Hamagaki X. X. Bai O. Hashimoto X. X. Bai S. Kadota K. Kimura Y. Miake S. Nagamiya K. Omata Y. Shida I. Tanihata N. Yoshikawa 《Physics letters. [Part B]》1985,150(6):416-420
The spectra of high-pT fragments have been measured at CM 90° in 800 A MeV C + C collisions for pT up to 1.8 GeV/c (proton), 2.5 GeV/c (deuteron) and 2.8 GeV/c (triton) at the Bevalac. Invariant cross sections were measured down to eight orders of magnitude lower than those for production of low momentum protons. The proton spectrum shows a significant deviation from the Boltzmann shape in the high-energy region. The spectra of deuterons and tritons are explained well by, respectively, squaring and cubing the observed proton spectra. 相似文献
97.
Masakazu Yoshikawa Hideto Yokoi Kohei Sanui Naoya Ogata 《Journal of polymer science. Part A, Polymer chemistry》1984,22(9):2159-2168
Separation of various alcohols and water through a membrane was carried out by means of a hydrogen-bonding interaction. A membrane obtained from poly(maleimide-co-acrylonitrile) was effective for a selective separation of water from aqueous alcohol solution by pervaporation technique. Spectroscopic analyses verified that this high selectivity was attributed to the hydrogen-bonding interaction between water and maleimide units in the membrane. 相似文献
98.
Shinichi Yano Kenji Tadano Koichiro Aoki Naokazu Koizumi 《Journal of Polymer Science.Polymer Physics》1974,12(9):1875-1887
Dielectric properties of poly(vinylidene fluoride) have been studied in the frequency range 20 Hz to 1 MHz and between 100 and 220°C, during heating and cooling. The dielectric constant and loss change abruptly at the temperature Tm corresponding to the melting point. At lower frequencies, two types of ionic conductin are observed. One appears below Tm and is attributed to interfacial polarization. The other occurs above Tm and is related to electrode polarization. These results suggest that a crystalline polymer is a heterogeneous medium for ionic transport, while the melt is a homogeneous medium. From these results, the nature of ac ionic conduction in crystalline polymers is discussed. At high frequency, the α relaxation is observed below Tm. It is due to the molecular motion in the crystalline region and disappears at Tm. 相似文献
99.
Low-lying levels in 188pt were studied using the 191Ir(p, 4nγ)188Pt reaction and higher spin members of the quasi-γ band were proposed. The results resemble a slightly perturbed phonon scheme, from comparisons with macroscopic calculations which would remove the degeneracy of the phonon multiplets. The importance of mass parameter renormalization is pointed out. 相似文献
100.
Masayuki Yoshikawa Yoshiharu Ikeda Hiroshi Kayakiri Kohei Takenaka Isao Kitagawa 《Tetrahedron letters》1982,23(45):4717-4720
By use of a decarboxylation reaction with lead tetraacetate and a deacetoxylation reaction with sodium borohydride as key-reactions, paromamine ( and tri-N-benzyloxycarbonylparomamine () were synthesized from D-glucosamine. 相似文献