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991.
Kohei Saito Yuya Watabe Takashi Fujihara Toshiyuki Takayanagi Jun-ya Hasegawa 《Journal of computational chemistry》2020,41(11):1130-1138
Spin-inversion mechanisms in O2 binding to a model heme complex, consisting of Fe(II)-porphyrin and imidazole, were investigated using density-functional theory calculations. First, we applied the recently proposed mixed-spin Hamiltonian method to locate spin-inversion structures between different total spin multiplicities. Nine spin-inversion structures were successfully optimized for the singlet–triplet, singlet–quintet, triplet–quintet, and quintet–septet spin-inversion processes. We found that the singlet–triplet spin-inversion points are located around the potential energy surface region at short Fe–O distances, whereas the singlet–quintet and quintet–septet spin-inversion points are located at longer Fe–O distances. This suggests that both narrow and broad crossing models play roles in O2 binding to the Fe-porphyrin complex. To further understand spin-inversion mechanisms, we performed on-the-fly Born-Oppenheimer molecular dynamics calculations. The reaction coordinates, which are correlated to the spin-inversion dynamics between different spin multiplicities, are also discussed. 相似文献
992.
Yutaro Sugiura Toshiyuki Takayanagi Masanori Tachikawa 《International journal of quantum chemistry》2020,120(22):e26376
The positron-electron correlation-polarization potential model is used to calculate annihilation spectra of carbon disulfide and benzene. We assume that the positron is captured in the vibrationally excited states of the target molecule through vibrational Feshbach resonances. Using the standard normal mode representation, we calculated the resonance energies and widths for each vibrational mode. The resonance widths were calculated with Fermi's Golden Rule approximation, where the time-dependent wave packet approach has been applied. We found that vibrational resonances of infrared-active modes play a dominant role in resonant annihilation; however, infrared-inactive modes also contribute to the annihilation spectrum through polarizability changes along normal mode coordinates. 相似文献
993.
Masakazu Koga Koichi Tamai Mitsunori Ueda Toshinori Uchida Toshiyuki Yamamuro Masahiro Shigeta 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8-9):2099-2100
We have synthesized carbocyclic 5'-nor oligodeoxynucleotides with a shortened overall chain length lacking the 5'-methylene. Their hybridization properties with DNA and RNA were investigated by UV and CD melting curves. These oligomers formed unstable duplexes with DNA, but formed stable duplexes with RNA selectively. In addition, these oligomers were very stable against nucleases. 相似文献
994.
Toshiyuki Akazawa Takafumi Nomura Masayoshi Kobayashi Keiichiro Matsushima Hironori Minoshima Tohru Kanno 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6-7):1893-1897
Microcrystals of cattle bone-originated apatites (r-HAp) were prepared by the dissolution-precipitation and freeze-drying processes. The r-HAp particles obtained gave 128 m 2 ;g m 1 specific surface area and 0.376 cm 3 ;g m 1 total pore volume and strong basic surface with mesopores. All the adsorption isotherms of water vapor at 288-308 K for the r-HAp powders obeyed IV-type in a classification of the BDDT. In the repeated adsorption-desorption operations, an adsorption hysteresis resulting from mesopores was recognized. The amounts of water vapor adsorbed obtained in the first adsorption operation were larger than those in the second adsorption operation, indicating that some portion of water vapor adsorbed to be irreversible adsorption. The water vapor-adsorption heats for the r-HAp were 45-60 kJ;mol m 1 , whose values were higher than natural diatomite. The amounts of water vapor adsorbed for the r-HAp were larger than those for the adsorbents, such as natural diatomite, aerosol silica, and activated carbon, at the relative partial pressures of 0-0.7. 相似文献
995.
Hajime Yasuda Eiji Ihara Toshiyuki Hayakawa Takamaro Kakehi 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1929-1944
Abstract Organolanthanide(III) initiated polymerization of methyl methacryate gave both syndiotactic and isotactic living polymers of high molecular weight. Organolanthanide(III) initiated polymerization of alkyl acrylates also gave high molecular weight poly(alkyl acrylate)s with very narrow molecular weight distribuion in high yield. Molecular weights of the resulting polymers increased linearly with the conversion. Random and block copolymerizations of alkyl acrylates with methyl methacrylate were realized successfully. For the sake of development of the olefin polymerization catalyst, bulky substituents were introduced into Me2Si bridged Cp rings and they were used as ligands for the lanthanide complexes. Tri- and divalent lanthanide complexes with such ligands showed high activity for olefin polymerization and gave high molecular weight polyolefins. 相似文献
996.
Tatsuro Ouchi Toshiyuki Emura Takashi Taniguchi Itsuo Maeda 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1527-1542
Abstract The polymer of 1- 3-O [(R)1-(L-alanyl-D-isoglutamyl carbonyl)ethyl] α-D-glucopyranos-6-O-carbonyl ethylene was synthesized as a acryloyl type polymer by fixing the D-glucose analog (GADP) of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP), which is the minimum required structure responsible for the immunoadjuvant activity of bacterial cell-wall peptidoglycan. N- [2-(1,2-O-Isopropylidene-6-O-acryloyl-α-D-glucofuranos-3-Oyl)-(R)-propionyl] -L-alanyl-D-isoglutamine benzyl ester (6) was prepared as a key monomer in the synthesis. The homopolymerization of 6 and the copolymerization of 6 with hydrophobic acryloyl monomers were carried out in benzene at 60°C by using 2,2′-azobisisobutyronitrile as a radical initiator to give homopolymer 7 and copolymer 10, respectively. Removal of isopropylidene and benzyl protecting groups from 7, 10 and 8, 11 was carried out by acid treatment with trifluoroacetic acid/water (6:1 v/v) and by catalytic hydrogenolysis with palladium carbon, respectively, to afford the homopolymer 9 and the copolymer 12. 相似文献
997.
p-Chloromethylstyrene, a useful monomer for a starting material in preparation of functional polymers, is conveniently synthesized by the chloromethylation of 2-phenyl-ethyl bromide followed by dehydrobromination. This procedure is simpler and the yield is higher than those of methods previously described. Radical copolymerizations of this compound with styrene and methyl methacrylate were studied at 60°C. From the copolymerization with styrene, Q and e values for p-chloromethylstyrene were calculated as Q = 1.13 and e = ?0.58. Similarly, the copolymerization parameters with methyl methacrylate were obtained as Q = 1.16 and e = ?0.69. 相似文献
998.
Shin-ichi Miyashita Kazumi Inagaki Shigehiro Naito Kumiko Shindoh Tomohiro Narukawa Yanbei Zhu Takayoshi Kuroiwa Akiharu Hioki Toshiyuki Fujimoto Koichi Chiba 《Analytical and bioanalytical chemistry》2013,405(25):8347-8362
To support skill upgrading in analysis of inorganic constituents of environmental and food samples, the National Metrology Institute of Japan (NMIJ) and the National Food Research Institute (NFRI) have organized a proficiency test (PT) of determination of Mn, Fe, Cu, Zn, As, and Cd in brown-rice flour based on the international standard (ISO/IEC 17043:2010). One hundred and thirty-three sets of reports were assessed by use of the E n -number and z-score approaches in accordance with ISO/IEC 17043 and the international harmonized protocol for PT. The PT results and analytical procedures, reported in detail, were reviewed, and possible technical reasons for questionable or unsatisfactory results are discussed.
Distribution of reported values for cadmium in the test material according to the measurement methods used. The mean values reported with standard deviations (error bars) are given in the order of lower to higher values. Solid lines indicate the expanded uncertainty (coverage factor k = 2) of assigned value. 相似文献
999.
Daisuke Kosumi Toshiyuki Kusumoto Mitsuru Sugisaki Yoshiro Iinuma Yuki Takaesu Masahiko Iha Hideki Hashimoto 《Journal of luminescence》2011,131(3):515-10770
Ultrafast relaxation kinetics of fucoxanthin in polar and non-polar solvents have been studied by femtosecond pump-probe spectroscopy. Transient absorption associated with S1 or intramolecular charge transfer (ICT) excited state has been observed following either one-photon excitation to the optically allowed S2 state or two-photon excitation to the symmetry-forbidden S1 state. The results suggest that the ICT state formed after excitation of fucoxanthin in a polar solvent is a distinct excited state from S1. 相似文献
1000.
We derive relations between the Aharonov invariants and Tamanoi’s Schwarzian derivatives of higher order and give a recursive
formula for Tamanoi’s Schwarzians. Then we propose a definition of invariant Schwarzian derivatives of a nonconstant holomorphic
map between Riemann surfaces with conformal metrics. We show a recursive formula also for our invariant Schwarzians. 相似文献