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941.
Vancoillie S Hendrickx M Nguyen MT Pierloot K Ceulemans A Mack J Kobayashi N 《The journal of physical chemistry. A》2012,116(15):3960-3967
The MCD spectra of meso-triarylsubporphyrins show a sign anomaly which is correlated with the acceptor properties of the aryl substituent. From the spectra, magnetic moments of the excited states are determined. In the context of a simplified orbital model, the sign change is attributed to the quenching of the magnetic moment of the LUMO by acceptor orbitals of the substituent. The actual calculation of this moment presents a major challenge to computational methods. It is shown that wave function techniques based on CASSCF underestimate the covalency effects that are responsible for the quenching. In contrast, a CI method based on DFT orbitals yields excellent results, which fully support the orbital model. 相似文献
942.
Hiroshi Yabuno Hiroyuki Kaneko Masaharu Kuroda Takeshi Kobayashi 《Nonlinear dynamics》2008,52(1-2):137-149
A technique for dimensional reduction of nonlinear delay differential equations (DDEs) with time-periodic coefficients is
presented. The DDEs considered here have a canonical form with at most cubic nonlinearities and periodic coefficients. The
nonlinear terms are multiplied by a perturbation parameter. Perturbation expansion converts the nonlinear response problem
into solutions of a series of nonhomogeneous linear ordinary differential equations (ODEs) with time-periodic coefficients.
One set of linear nonhomogeneous ODEs is solved for each power of the perturbation parameter. Each ODE is solved by a Chebyshev
spectral collocation method. Thus we compute a finite approximation to the nonlinear infinite-dimensional map for the DDE.
The linear part of the map is the monodromy operator whose eigenvalues characterize stability. Dimensional reduction on the
map is then carried out. In the case of critical eigenvalues, this corresponds to center manifold reduction, while for the
noncritical case resonance conditions are derived. The accuracy of the nonlinear Chebyshev collocation map is demonstrated
by finding the solution of a nonlinear delayed Mathieu equation and then a milling model via the method of steps. Center manifold
reduction is illustrated via a single inverted pendulum including both a periodic retarded follower force and a nonlinear
restoring force. In this example, the amplitude of the limit cycle associated with a flip bifurcation is found analytically
and compared to that obtained from direct numerical simulation. The method of this paper is shown by example to be applicable
to systems with strong parametric excitations. 相似文献
943.
Prognosis of severe ischemic heart disease with no indication of percutaneous coronary intervention or coronary artery bypass
grafting still remains poor. Extracorporeal shock wave therapy was introduced for medical therapy more than 20 years ago to
break up kidney stones. We have demonstrated that extracorporeal cardiac shock wave therapy at a low level of ~10% of energy
density that used for urinary lithotripsy treatment, effectively induces coronary angiogenesis and improves myocardial ischemia
in a porcine model of chronic myocardial ischemia in vivo. On the basis of the promising results in animal studies, we have
recently developed a new, non-invasive angiogenic therapy with low-energy shock waves for ischemic heart disease. Our extracorporeal
cardiac shock wave therapy improved symptoms and myocardial ischemia in patients with severe coronary artery disease. These
beneficial effects of the shock wave therapy persisted for at least 12 months. Importantly, no procedural complications or
adverse effects were noted. These results indicate that our extracorporeal cardiac shock wave therapy is an effective and
non-invasive treatment for ischemic heart disease. To further confirm the usefulness and safety of our SW therapy, we are
currently conducting the second clinical trial in a randomized and placebo-controlled manner.
相似文献
944.
A dielectric constant measurement was carried out on perovskite-type ferroelectrics KNbO3 over a wide range of temperature under high pressure. The temperature- and pressure-dependence of the dielectric constant clarified that all temperatures of the transitions from the ferroelectric rhombohedral to orthorhombic, to tetragonal and then to the paraelectric cubic phase, decrease with increasing pressure. These results indicate that the orthorhombic–tetragonal transition takes place at 8.5 GPa and the tetragonal–cubic transition at 11 GPa, at room temperature. 相似文献
945.
Asahi K. Ogawa H. Ueno H. Kobayashi Y. Sato W. Yoshimi A. Watanabe H. Kameda D. Miyoshi H. Sakai K. Imai N. Yoneda K. Watanabe Y. X. Fukuda N. Aoi N. Yoshida A. Kubo T. Ishihara M. 《Hyperfine Interactions》2001,136(3-8):183-187
Magnetic dipole and electric quadrupole moments of nuclei in the light-mass neutron-rich region have been studied by taking
advantage of spin-polarized radioactive nuclear beams that have been obtained from the projectile fragmentation reaction.
Analyses of the results reveal a few interesting phenomena characteristic of nuclear structures in this region. In particular,
we report in some detail the latest result on the magnetic moment of the 17C ground state. The distinctly small value of the g-factor obtained, |g(17C)|=0.5054±0.0025, clearly excludes a I
π=1/2+ candidate for the spin-parity assignment of this marginally bound nucleus, providing a reasonable account of the non-halo
nature reported in recent breakup reaction experiments. Finally, future plans at the upcoming radioactive beam facility presently
under construction at RIKEN are briefly mentioned.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
946.
Kenta Tanaka Bunichiro Yamada Christopher M. Fellows Robert G. Gilbert Thomas P. Davis Lachlan H. Yee Gregory B. Smith Mark T. L. Rees Gregory T. Russell 《Journal of polymer science. Part A, Polymer chemistry》2001,39(22):3902-3915
The methyl acrylate dimer (MAD) is a sterically hindered macromonomer, and the propagating radical can fragment to an unsaturated end group. The propagation‐rate coefficient (kp) for MAD was obtained by pulsed‐laser polymerization (PLP). The Mark–Houwink–Sakaruda parameters required for the analysis of the molecular weight distributions (MWDs) were obtained by multiple‐detector gel permeation chromatography (GPC) with on‐line viscometry. The small radical created by the fragmentation results in a short‐chain polymer that means the MWD may no longer be given by that expected for “ideal” PLP conditions; simulations suggest that the degree of polymerization required for “ideal” PLP conditions can be obtained from the primary point of inflection provided the GPC traces also show a clear secondary inflection point (radicals terminated by the second, rather than the first, pulse subsequent to initiation). Over the temperature range of 40–75 °C, the data can be best fitted by kp/dm3 mol?1 s?1 = 106.1 exp(?29.5 kJ mol?1), with a moderately large joint confidence interval for the Arrhenius parameters. The data are consistent with an increased activation energy and reduced frequency factor as compared with acrylate or methacrylate; both of these changes can be ascribed to hindrance. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3902–3915, 2001 相似文献
947.
Reiko Saito Yoshiki Okuno Hiroaki Kobayashi 《Journal of polymer science. Part A, Polymer chemistry》2001,39(20):3539-3546
A novel template monomer with multiple methacryloyl groups was synthesized with β‐cyclodextrin by the acetylation of primary hydroxyl groups and the esterification of secondary hydroxyl groups with methacrylic acid anhydride. The average number of methacryloyl groups in the monomer was 11. The radical polymerization of the monomer was carried out with the following initiators: α,α′‐azobisisobutylonitrile, H2O2? Fe2+ redox initiator, p‐xylyl‐N,N‐dimethyldithiocarbamate (XDC), and α‐bromo‐p‐xylyl‐N,N‐dimethyldithiocarbamate (BXDC). When the concentration of the monomer was less than 4.12 × 10?3 M, polymerization was limited inside the molecule, and gelation of the system was hindered. For controlled radical photopolymerization with XDC and BXDC, the methacryloyl groups of the monomer were homogeneously polymerized, and poly(methacrylic acid) with a narrow molecular weight distribution was obtained by the hydrolysis of the polymerized products. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3539–3546, 2001 相似文献
948.
J I Kobayashi Y Inaba M Shiro N Yoshida H Morita 《Journal of the American Chemical Society》2001,123(46):11402-11408
Eight highly modified Daphniphyllum alkaloids with unprecedented fused hexa- or pentacyclic skeletons, daphnicyclidins A-H (1-8), have been isolated from the stems of Daphniphyllum humile and D.teijsmanni, and their structures were elucidated on the basis of spectroscopic data and chemical means. The stereochemistry was elucidated by combination of NOESY correlations, X-ray crystallographic data, and CD analyses. 相似文献
949.
Structural conversion and spin separation in Bis(ferrocenylethynyl)anthraquinones triggered by proton-coupled intramolecular electron transfer. 总被引:1,自引:0,他引:1
M Murata M Yamada T Fujita K Kojima M Kurihara K Kubo Y Kobayashi H Nishihara 《Journal of the American Chemical Society》2001,123(51):12903-12904
950.
An electrochemical response of glucose and lactate biosensors which were prepared by coating a platinum electrode with a thin film composed of concanavalin A and mannose-labeled glucose oxidase (GOx) or lactate oxidase (LOx) was evaluated in the presence of ferrocene derivatives as electron mediator. Both glucose and lactate biosensors showed catalytic current to glucose and lactate, respectively, in cyclic voltammetry, suggesting that the ferrocene derivatives can mediate electron transport smoothly from the reduced forms of GOx and LOx in the thin films to the electrode. Among the three kinds of ferrocene derivatives used, ferrocenylmethanol was found to be the most suitable electron mediator because of its low oxidation potential. The glucose and lactate sensors gave useful calibration graphs, in which higher detection limits were reached as compared with those observed when the sensors were operated in the absence of electron mediator. 相似文献