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Article type: Cover
2015 Volume 70 Issue 10 Pages
Cover1-
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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Kazuo Ueda
Article type: Article
2015 Volume 70 Issue 10 Pages
737-
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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Article type: Index
2015 Volume 70 Issue 10 Pages
738-739
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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Satoshi Mihara
Article type: Article
2015 Volume 70 Issue 10 Pages
740-741
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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Takumi Noguchi
Article type: Article
2015 Volume 70 Issue 10 Pages
742-751
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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In photosynthesis performed by plants and cyanobacteria, light energy is converted into chemical energy by reduction of CO_2 to synthesize sugars. The key reaction in the photosynthetic process is oxidation of water, which functions as an ultimate electron donor. Molecular oxygen released as a byproduct of water oxidation, which started 〜2.5 billion years ago by cyanobacteria, produced oxygenic atmosphere and promoted the evolution of life. In this article, the basic mechanism of the light-energy conversion of photosynthesis is briefly explained and recent studies of the elaborate mechanism of photosynthetic water oxidation are introduced focusing on proton-coupled electron transfer reactions.
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Yoshiyuki Inoue
Article type: Article
2015 Volume 70 Issue 10 Pages
752-759
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space telescope has recently measured it at 0.1-820 GeV and revealed that the cosmic GeV gamma-ray background is composed of blazars, radio galaxies, and star-forming galaxies. However, Fermi still leaves the following questions. Those are dark matter contribution, origins of the cosmic MeV gamma-ray background, and the connection to the IceCube TeV-PeV neutrino events. In this article, I will review the current understandings of the cosmic gamma-ray background and discuss future prospects of cosmic gamma-ray background radiation studies.
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Koji Miyamoto, Akio Kimura, Taichi Okuda
Article type: Article
2015 Volume 70 Issue 10 Pages
760-764
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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We have uncovered that the d-electron-based surface state of W(110) shows a Dirac-cone-like feature with remarkable spin texture within a spin-orbit-induced symmetry gap. The C_<2v> symmetry of W(110) surface strongly influences this spin-polarized Dirac-cone-like surface state. Consequently, the Dirac-cone-like feature appears along <ΓH>^^^- and <ΓS>^^^-, while it is strongly deformed along <ΓN>^^^-. The observed results are well described by the model calculations based on an effective Hamiltonian with C_<2v>. The spin texture of the flattened Dirac cone obtained from model calculations is aligned along <ΓN>^^^- direction. This situation would substantially enhance the spin relaxation time. This finding opens a new avenue in the study of d-electron-based topological insulator with C_<2v> symmetry.
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Tomoki P. Terada
Article type: Article
2015 Volume 70 Issue 10 Pages
765-769
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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We have studied the differentiation of mouse embryonic stem cell (ES cell) into either trophectoderm or primitive endoderm by simulating the relevant gene regulation network in silico. Our results suggest that the slowness of the transcriptional apparatus formation/dissolution for Nanog gene is critical for the heterogeneity of Nanog protein expression, as well as the discreteness of the cell state, which discriminates ES cell, trophectoderm and primitive endoderm.
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Ikufumi Katayama, Jun Takeda, Masahiro Kitajima
Article type: Article
2015 Volume 70 Issue 10 Pages
770-775
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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Using ultrabroadband and ultrashort laser pulses, we investigated coherent phonons in graphene, carbon nanotubes, and graphite. By resolving spectrum of probe pulses, resonant properties due to the strong electron-phonon coupling were clearly observed. In graphene and defected graphite, the double resonant Raman scattering process dominates the coherent phonon generation and detection processes, leading to the excitation of nanoscale coherent optical-phonon wave-packet. In metallic carbon nanotubes, strong resonance appears at the energy below the van-Hove singularity by an amount of the phonon energy, indicating dominant contribution of Stokes stimulated Raman scattering process. The results demonstrate that wavelength-resolved coherent phonon spectroscopy is crucial for investigating the electron-phonon coupling dynamics in materials.
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Joji Nasu, Masafumi Udagawa, Yukitoshi Motome
Article type: Article
2015 Volume 70 Issue 10 Pages
776-781
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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The Kitaev model has recently attracted considerable attention in broad areas of research owing to the topological nature and quantum spin-liquid (QSL) ground states. This is defined on a honeycomb lattice, and is exactly solvable due to the Ising conserved quantities on each hexagon. In this study, we investigate the thermodynamics of a three-dimensional extension of the Kitaev model defined on a hyperhoneycomb lattice. This model can be rewritten as a free Majorana fermion system coupled with Ising variables. Using this representation, we have performed the Monte Carlo simulation and analyzed the thermodynamic properties. We find that the model exhibits a finite-temperature phase transition between the QSLs and paramagnet in the whole parameter range. This result indicates that the QSL phases at low temperatures are always distinguished from the high-temperature paramagnet by a phase transition. We also find that the difference between QSL and paramagnet comes from the topological nature of the excitations.
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[in Japanese]
Article type: Article
2015 Volume 70 Issue 10 Pages
782-784
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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[in Japanese]
Article type: Article
2015 Volume 70 Issue 10 Pages
785-788
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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[in Japanese]
Article type: Article
2015 Volume 70 Issue 10 Pages
789-791
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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[in Japanese]
Article type: Article
2015 Volume 70 Issue 10 Pages
792-
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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[in Japanese]
Article type: Article
2015 Volume 70 Issue 10 Pages
793-
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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[in Japanese]
Article type: Article
2015 Volume 70 Issue 10 Pages
793-794
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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Article type: Appendix
2015 Volume 70 Issue 10 Pages
795-799
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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Article type: Appendix
2015 Volume 70 Issue 10 Pages
799-800
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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[in Japanese]
Article type: Appendix
2015 Volume 70 Issue 10 Pages
800-801
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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Article type: Appendix
2015 Volume 70 Issue 10 Pages
802-806
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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Article type: Appendix
2015 Volume 70 Issue 10 Pages
807-808
Published: October 05, 2015
Released on J-STAGE: August 21, 2019
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