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71.
Let X be an algebraic K3 surface, and let L be a base point free and big line bundle on X. If X admits a map of degree 2 to the projective plane branched over a smooth sextic and L is the pullback of the line bundle
O\mathbbP2(3),{\mathcal{O}_{\mathbb{P}^{2}}(3),} then the gonality of the smooth curves of the complete linear system |L| is not constant. The polarized K3 surface (X, L) consisting of the K3 surface X and the line bundle L is called Donagi–Morrison’s example. In this paper, we give a necessary and sufficient condition for the polarized K3 surface
(X, L) consisting of a 2-elementary K3 surface X and an ample line bundle L to be Donagi–Morrison’s example. 相似文献
72.
Poly(lactic acid) (PLA) particles dispersed in water were transformed into nanofibers by simply heating above the glass transition temperatures of the hydrated PLAs. 相似文献
73.
Takuya Yokosaka Akinari Hamajima Tetsuhiro Nemoto Yasumasa Hamada 《Tetrahedron letters》2012,53(10):1245-1248
We developed a novel method for the asymmetric synthesis of highly functionalized γ-lactams through an organocatalytic aza-Michael–Michael reaction cascade using fumaric acid amide esters as multi-reactive substrates. Using chiral primary or secondary amine organocatalysts, we obtained two types of γ-lactams with three contiguous chiral centers in moderate to good yield with excellent enantioselectivity and diastereoselectivity. 相似文献
74.
In this article, we shall prove that every bipartite quadrangulation G on the torus admits a simple closed curve visiting each face and each vertex of G exactly once but crossing no edge. As an application, we conclude that the radial graph of any bipartite quadrangulation on the torus has a hamiltonian cycle. Copyright © 2011 Wiley Periodicals, Inc. J Graph Theory 69:143‐151, 2012 相似文献
75.
We report calculations of the ground state energy and binding curve of the chromium dimer using the variational and diffusion quantum Monte Carlo (VMC and DMC) methods. We examined various single‐determinant and multideterminant wavefunctions multiplied by a Jastrow factor as a trial/guiding wavefunction for VMC/DMC. The molecular orbitals in the single determinants were calculated using restricted or unrestricted Hartree–Fock or density functional theory (DFT) calculations where five commonly used local (SVWN5), semilocal (PW91 and BLYP), and hybrid (B1LYP and B3LYP) functionals were examined. The multideterminant expansions were obtained from the generalized valence bond and (truncated) unrestricted configuration interaction with single and double excitations (UCISD) methods. We also examined a UCISD wavefunction in which UCISD expansions were added to the UB3LYP single‐determinant reference, and their coefficients were optimized at the VMC level. In addition to the wavefunction dependence, the effects of pseudopotentials and backflow transformation were also investigated. The UB3LYP single‐determinant and multideterminant wavefunctions were found to give the variationally best DMC energies within the framework of single‐determinant and multideterminants, respectively, though both the DMC energies were higher than twice the DMC atomic energy. Some of the VMC binding curves show a flat or quite shallow well bottom, which gets recovered deeper by DMC. All the DMC binding curves have a minimum indicating a bound state, but the unrestricted ones overestimate the equilibrium bond length. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 相似文献
76.
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
77.
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
78.
Dr. Daichi Kawauchi Kenta Noda Dr. Yoshiyuki Komatsu Dr. Kei Yoshida Dr. Hirofumi Ueda Prof. Dr. Hidetoshi Tokuyama 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(68):15793-15798
An aerobic dehydrogenation of nitrogen-containing heterocycles catalyzed by Grubbs catalyst is developed. The reaction is applicable to various nitrogen-containing heterocycles. The exceptionally high functional group compatibility of this method was confirmed by the oxidation of an unprotected dihydroindolactam V to indolactam V. Furthermore, by taking advantage of the oxygen-mediated structural change of the Grubbs catalyst, we integrated ring-closing metathesis and subsequent aerobic dehydrogenation to develop the novel assisted-tandem catalysis using molecular oxygen as a chemical trigger. The utility of the assisted-tandem catalysis was demonstrated by the concise synthesis of N-containing fused heteroarenes including a natural antibiotic, pyocyanine. 相似文献
79.
Kenta Sato Dr. Masashi Hasegawa Yuki Nojima Nobuyuki Hara Dr. Tomohiko Nishiuchi Prof. Dr. Yoshitane Imai Prof. Dr. Yasuhiro Mazaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(4):1323-1329
A curved stereogenic [6]paraphenylene ([6]PP), anchoring a chiral binaphthyl scaffold at 7,7’-positions, was prepared and investigated for its properties as a solid-state circularly polarized luminescence (CPL) dye. X-ray analysis revealed a helically twisted structure of PP units induced by axial chirality of binaphthyl framework. The curved [6]PP exhibits fluorescence in powder and polymethyl methacrylate (PMMA) film as well as solution. A significant increase in quantum yield was observed for a non-fluid PMMA film owing the suppression of the molecular motion. The gCPL values of the dye in solution and as PMMA film were almost the same (4.3–4.4×10−3) and lager than that in powder. TD-DFT calculations in the excited state suggest that the exciton can be delocalized into a twisted PP unit to produce a larger magnetic transition dipole moment. 相似文献
80.
Nakamura M Takahashi K Fujioka T Kado S Sakamoto H Kimura K 《Journal of the American Society for Mass Spectrometry》2003,14(10):1110-1115
The photoinduced changes of metal-ion complexing ability of crowned spirobenzopyran derivatives were studied by using electrospray ionization mass spectrometry (ESI-MS). Stability constants for the complexation with various metal ions in methanol under visible-irradiation conditions were determined for the first time by ESI-MS. It was found that the stability constants of crowned bis(spirobenzopyran) derivatives with metal ions are decreased dramatically by visible irradiation due to the disappearance of powerful ionic interaction between phenolate anion(s) of the merocyanine form of their spirobenzopyran moiety and a metal ion bound to their crown ether moiety, and the decrease in the stability constants is more pronounced for the multivalent metal-ion complexes. A theoretical consideration was also made to attain reliable values of stability complexes for metal-ion complexes of crown compounds. 相似文献