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131.
Clustering in nuclei is discussed putting emphasis on the investigation of the role of nuclear clustering in neutron-rich nuclei. The subjects we discuss include clustering in neutron-rich Be, B and C isotopes, clustering in the island of inversion around N = 20, and clustering in the region with A ≈ 40. Be isotopes present us typical examples of clustering in neutron-rich nuclei not only in their ground band states but also in their excited band states, for which we show the analyses based on antisymmetrized molecular dynamics (AMD). Clustering in Be isotopes near neutron dripline is intimately related to the breaking of the neutron magic number N = 8. In this connection we report our study about the possible relation of the clustering with the breaking of the neutron magic number N = 20 in the island of inversion including 32Mg and 30Ne. Our discussion is not only about the positive parity states but also about negative parity states. Recently in the latter half of sd shell and in the pf shell many excited rotational bands with large deformation have been found to exist. Since the first excited K π = 0+ and K π = 0- bands in 40Ca have been regarded as constituting inversion doublet bands having the 36Ar + α structure, and since the first excited K π = 0- band in 44Ti has been concluded to have 40Ca + α structure through the α transfer reaction and by using the unique α optical potential on 40Ca, it is important to investigate the role of α clustering in these newly-found rotational bands with large deformation. We will report the AMD study about this problem. 相似文献
132.
The magnetic field effects (MFEs) on the electron transfer reactions from indole derivatives to flavin derivatives in micellar solutions are studied. The MFEs on the free radical yields observed by transient absorption (TA) reflect effectively the association of the donor and acceptor molecules with the micelles. In the system of riboflavin and indole, the MFE increases rapidly with increasing concentration of sodium dodecyl sulfate (SDS) higher than the critical micellar concentration. In contrast, in the system of flavin mononucleotide and indole, the increase of MFE is very slow even at higher concentrations of SDS. This result shows that riboflavin is well associated with the SDS micelle and the diffusion process of the radical pair is restricted by the micellar cages. The MFE in the system of riboflavin and indole is twice as large as that of riboflavin and tryptophan. This result shows the difference of the dynamics of radicals in micelles. The escape rate of the cation radical generated from tryptophan is much faster than that generated from indole. The dependence of the MFEs on the type of surfactant is studied. The effect of the Coulomb force between the ionic reactant molecules and the charged head group of the surfactant and the effect of the molecular size are discussed by comparison of the MFE intensities. 相似文献
133.
Afshin Ebrahimi Masaaki Kitano Kazushi Iyatani Yu Horiuchi Masato Takeuchi Masaya Matsuoka Masakazu Anpo 《Research on Chemical Intermediates》2013,39(4):1593-1602
Visible light-responsive TiO2 (Vis-TiO2) thin films were successfully developed by applying a radio-frequency magnetron sputtering deposition method by controlling various sputtering parameters such as the substrate temperature, Ar gas pressure, and the target-to-substrate distance. UV–Vis, XRD and SEM investigations revealed that optical property, the crystal structure, and photocatalytic activity of Vis-TiO2 are strongly affected by the sputtering parameters during the deposition step. Vis-TiO2 was found to act as an efficient photocatalyst for the H2 and O2 evolution from water under visible light irradiation (λ ≥ 420 nm). SIMS investigations have revealed that a slight decrease in the O/Ti ratio of the TiO2 thin films plays an important role in the modification of the electronic properties of Vis-TiO2 thin films, enabling them to absorb visible light. 相似文献
134.
135.
Variation of the ferroelectric phase transition has been investigated for a series of isomorphous donor (D)-acceptor (A) charge-transfer complexes composed of 4,4'-dimethyltetrathiafulvalene (DMTTF) and tetrahalo-p-benzoquinones by measurements of dielectric susceptibility, X-ray diffraction, and infrared molecular vibrational spectra. The neutral-ionic phase transition of DMTTF-p-chloranil at 65 K accompanies a dielectric peak anomaly associated with the DA stack dimerization. Successive halogen replacement by bromine in the component tetrahalo-p-benzoquinone molecule expands the lattice along the DA stack of the DMTTF complex, and reduces the critical temperature steeply toward zero temperature in an analogous way to the critical behavior of quantum ferroelectrics. The 2,6-dibromo-substituted compound showing the behavior of the quantum paraelectricity is located in the immediate vicinity of the quantum critical point of this phase diagram as signified also by enhancement of the ionicity, the dielectric susceptibility, and the dynamical dimeric distortion at the lowest temperature. 相似文献
136.
Kuniko Kimura Kei Kobayashi Toshihisa Horiuchi Kazumi Matsushige 《Applied Surface Science》2006,252(15):5489-5494
We have developed a molecular orientation control technique for polymers utilizing contact-mode atomic force microscopy (AFM). In this paper, we studied the molecular alignment mechanism of this technique by applying it to poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)). The resultant alignment and formed crystal size were strongly dependent on the temperature during the modification. They also depended on the scan line spacing of the modification. These results made the alignment mechanism clear. The obtained molecular alignment was stable against the heat treatment even at the temperatures just below Tm. 相似文献
137.
An orthorhombic YBa2Cu3O6.9 crystal with Tc=91 K, in which synthetic twins are inevitably contained, is so sensitive to electron irradiation that a structural change easily occurs at the twin boundary, causing the phase transformation from orthorhombic to tetragonal system. We have succeeded in taking images, in which lattice fringes sharply bend at the boundary, using an ultra-high-resolution high-voltage electron microscopy (UHR-HVEM) and the intrinsic structure of the twin boundary could be analyzed to be of oxygen-centered type. The diffraction streak, which is excited only from the boundary region, is explained with help of optical diffraction for a model structure of tilted anti-phase boundary. Atomic knock-on displacements start to occur also in the matrix, being a little apart from the boundary, even at very early stage of electron beam irradiation.Presented at the workshop on High-Voltage and High Resolution Electron Microscopy, February 21–24, 1994, Stuttgart, Germany. 相似文献
138.
139.
Tohru Kanno Jun-ichi Horiuchi Masayoshi Kobayashi 《Reaction Kinetics and Catalysis Letters》2000,70(1):73-80
Two functional lattice oxygens on the surface of a Mn-mixed Mg oxide were distinguished in the oxidative coupling of methane: the oxygen of MgO, which was active for methyl radical formation, and that of a Mn-Mg oxide solid solution, which was active for the dehydrogenation of ethane. 相似文献
140.
Shin Horiuchi Takeshi Hanada Noriya Izu Ichiro Matsubara 《Journal of nanoparticle research》2012,14(3):734
The microstructures and the organization mechanism of cerium oxide (ceria) nanospheres were investigated by transmission electron
microscopy. The ceria nanospheres with the diameter of 50–150 nm were produced by the polyol synthesis method with cerium
nitrate precursor and with polyvinylpyrrolidone (PVP) used as a protecting agent. Dose-limited observations performed by energy-filtering
transmission electron microscopy revealed that the ceria nanospheres were the aggregated products consisting of ceria nanocrystallites
~3 nm in size and PVP-derived polymer products. It was found that the ceria nanocrystallites were oriented within the nanospheres
by high-resolution transmission electron microscopy and selected-area electron diffraction. Selective adsorption of PVP on
the crystal facets of the ceria nanocrystallites was suggested, and the aggregation of the PVP-adsorbed ceria through cross-linking
reaction of PVP causes the crystal orientation. 相似文献