Silicon Science and Advanced Micro-Device Engineering II

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Authors: Masahisa Ito, Ryota Nagayasu, Tatsuki Tadenuma, Kosuke Suzuki, Ayako Sato, Hiromichi Adachi, Yoshiharu Sakurai, Yoshichika Ōnuki
Abstract: An experimental method of X-ray magnetic diffraction was applied to the ferromagnetic rare-earth compound CeRh3B2, and its spin and orbital magnetic form factors were measured independently for the first time. Our curve-fitting analysis shows that the orbital magnetic form factor is reproduced by the calculated atomic-model form factor of Ce-4f electrons under the dipole approximation. The comparison of the sum of form factors and the total magnetic form factor measured by the polarized neutron diffraction reveals anisotropic distribution of the magnetic moment in real space.
Authors: Kosuke Suzuki, Naoto Go, Shun Emoto, Ryutaro Yamaki, Masayoshi Itou, Yoshiharu Sakurai, Hiroshi Sakurai
Abstract: We compare two Co/Pd multilayers with correspondingly smooth and rough interfaces. The first is a Co (1.5 nm)/Pd (2.6 nm) multilayer with a smooth interface deposited by the MBE technique, and the second is a Co (1.6 nm)/Pd (4.0 nm) multilayer with a rough interface deposited by the sputter technique. Both multilayers have almost the same perpendicular magnetic anisotropy energy, 1.15 Merg/cc for the Co (1.5 nm)/Pd (2.6 nm) multilayer and 1.20 Merg/cc for the Co (1.6 nm)/Pd (4.0 nm) multilayer, respectively. The symmetry of the wave function, which is measured using the magnetic Compton profile, is almost the same for both multilayers. This suggests that the smooth interface controls the wave function and enhances the PMA energy even if the Co/Pd multilayer has a thinner Pd layer.
Authors: Kohjiro Kobayashi, Hiroshi Sakurai
Abstract: Compton profiles related to the electron momentum distribution are calculated using the DV-Xα method for a series of rare gases from He to Rn. To verify the criteria of the DV-Xα-derived Compton profiles, our results are compared with those obtained from the Hartree-Fock method. The trend of Compton profiles obtained from the DV-Xα method is discussed.
Authors: Kohjiro Kobayashi, Hiroshi Sakurai
Abstract: Isotropic and directional Compton profiles are calculated for 14 electron diatomic molecules, N2, CO, and BF, using the DV-Xα method. In order to investigate the effect of chemical bonding for Compton profiles, parallel and perpendicular directional Compton profiles to the molecules are calculated and compared with the results from Hartree-Fock and configuration interaction methods. The DV-Xα method could describe the more detailed character of covalent bonding than that of ionic bonding.
Authors: Shinichi Furusawa, Hiroshi Ochiai, Khoji Murayama
Abstract: Single crystals of lithium zinc titanate (Li2ZnTi3O8) were grown in a double-mirror type optical floating-zone furnace for the first time. Single crystals were characterized by X-ray powder diffraction and Laue measurements. The ionic conductivity of the single crystals was measured in the temperature range of 400–700 K. Below 600 K, the ionic conductivity of the single crystal is one to two orders of magnitude higher than that of polycrystalline Li2ZnTi3O8. In the temperature range of 550–600 K, the temperature dependence of the ionic conductivity shows non-Arrhenius behaviour.
Authors: Toru Kyomen, Ryuta Motani, Minoru Hanaya
Abstract: Powder of Pr-doped CaTiO3 red phosphor was prepared at 1473 K by a conventional solid-state reaction method with addition of B2O3 or SiO2 as a flux. Primary particle sizes of the prepared samples were increased by using B2O3 flux but decreased by using SiO2 flux. Clear planes, edges, or steps were observed on surfaces of the primary particles. The intensity of photoluminescence induced by irradiation of light with a wavelength longer than ∼350 nm was enhanced about three times by using B2O3 flux. The intensity of photoluminescence induced by irradiation of light with a wavelength shorter than ∼350 nm was enhanced about twice by using either B2O3 or SiO2 fluxes. The origin for the flux effects is discussed.
Authors: Kenji Kubota, Kaori Wakamatsu, Nobukazu Nameki, Yoshiharu Toyama
Abstract: Fibrin polymerization proceeds in a stepwise manner. In the first step, fibrinogen-to-fibrin conversion is triggered by the enzymatic fibrinopeptide release and protofibril formation/growth proceeds. In the following second step, lateral aggregation of the protofibrils occurs resulting in the network formation. Switchover from the first step to the second one can regulate the resultant network structure, and the lateral aggregation is considered to be induced by the interaction between the αC regions of two adjacent protofibrils. In order to clarify the characteristics of this interaction, we examined the cross-sectional diameter DC in addition to the hydrodynamic diameter (Stoke diameter) of fibrinogen molecule in various solution conditions. Cross-sectional diameter of intact fibrinogen was 4.7 nm in agreement with the molecular structure. On the other hand, fragment-X, in which the αC regions are deleted, had smaller DC of 4.2 nm. This means that the αC regions snuggle up to the molecular backbone, which is consistent with the model that the termini of the αC regions are tethered to the central E-region in the intact fibrinogen. On the other hand, fibrinogen at pH 3 had a cross-sectional diameter of 4.0 nm, which is further smaller than that of fragment-X. This is accounted for by the scheme that the αC regions are released from the central region, because side chains of Asp and Glu residues have neutral charge at pH 3. With the increase of ionic strength up to 150 mM at pH 3, fibrinogen molecules become to aggregate resulting in huge aggregated particles. Our results suggest that the released αC regions can interact attractively with each other through the hydrophobic interaction, which supports the proposed scheme of fibrin polymerization.
Authors: M. Gias Uddin, Tomohisa Moriguchi, Mayumi Ichimura, Kazuo Shinozuka
Abstract: A novel stem-loop structured fluorescent oligoDNA probe (molecular beacon probe) bearing a silylated pyrene derivative at C-5 position of deoxyuridine has been synthesized. The fluorescently labeled modified nucleoside has been incorporated into two consecutive positions in the stem segment of the DNA using an automated DNA synthesizer. The resulting modified DNA exhibited an excimer fluorescent signal upon binding to the fully matched complementary DNA strand. The excimer emission was, however, effectively quenched while it stays alone or it hybridizes to a single base mismatched complementary target.
Authors: Yasunobu Egawa, Masafumi Unno
Abstract: Recently we have been investigating solvent-free synthesis of siloxanes. Using no solvent gives less load to environment, and decreases cost in chemical industry. On the other hand, acidic or basic condition may not be applied to siloxanes bearing functional substituents. Therefore, the development of synthetic methods in neutral condition is desired. In this paper, we report the solvent-free thermal condensation of siloxane from silanol bearing vinyl group and strong electron-withdrawing 4-trifluoromethylphenyl group. Furthermore, we examined thermal properties of obtained vinyl-substituted silanol by TG-DTA measurement. With these results, we could determine the temperature of thermal condensation. We also elucidated the reaction pathway by tracing the reaction with GC-MS. Finally, we propose the possible reaction pathway from silanediol to cyclotrisiloxane (D3) and cyclotetrasilxane (D4).

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