Takeo Fujiwara

Domain boundary formation in helical multishell gold nanowire (2009)

Hoshi, Takeo, Fujiwara, Takeo

Helical multishell gold nanowire is studied theoretically for the formation mechanism of helical domain boundary. Nanowires with the wire length of more than 10 nm are relaxed by quantum mechanical...

Is education causally related to better health? A twin fixed-effect study in the USA (2009)

Fujiwara, Takeo, Kawachi, Ichiro

Background More years of schooling is generally associated with better health. However, this association may be confounded by unobserved common prior causes such as inherited ability, personality...

Electronic structure and effects of dynamical electron correlation in ferromagnetic bcc-Fe, fcc-Ni and antiferromagnetic NiO (2008)

Miura, Oki, Fujiwara, Takeo

LDA+DMFT method in the framework of the iterative perturbation theory (IPT) with full LDA Hamiltonian without mapping onto the effective Wannier orbitals. We then apply this LDA+DMFT method to...

Ill-Contact Effects of d-Orbital Channels in Nanometer-Scale Conductor (2008)

Shinaoka, Hiroshi, Hoshi, Takeo, Fujiwara, Takeo

Electronic current in a nanometer-size rod is theoretically investigated by an eigen-channel decomposition method in nonequilibrium Green's function formalism. Physical properties, such as the local...

Development of simulation package 'ELSES' for extra-large-scale electronic-structure calculation (2008)

Hoshi, Takeo, Fujiwara, Takeo

An early-stage version of simulation package ' ELSES' (Extra-Large-Scale Electronic-Structure calculation) is developed for electronic structure and dynamics of large systems, particularly, nm-scale...

Shifted COCG method and its application to double orbital extended Hubbard model (2008)

Yamamoto, Susumu, Sogabe, Tomohiro, Hoshi, Takeo, Zhang, Shao-Liang, Fujiwara, Takeo

We explains the shifted COCG method which can solve a series of the linear equations generated by numbers of scaler shifts, without time consuming matrix-vector operations, except at the only one...

Theory of large-scale matrix computation and applications to electronic structure calculation (2008)

Fujiwara, Takeo, Hoshi, Takeo, Yamamoto, Susumu

We review our recently developed methods for large-scale electronic structure calculations, both in one-electron theory and many-electron theory. The method are based on the density matrix...

Perinatal Factors Associated with Infant Maltreatment (2008)

Takeo Fujiwara, Makiko Okuyama, Haley Tsui, Karestan C. Koenen

Background: The association between birth outcomes and child maltreatment remains controversial. The purpose of this study is to test whether infants without congenital or chronic disease who are low...

Violence and Asthma: A Review (2008)

Takeo Fujiwara

Recent research shows that exposure to community violence is, directly and indirectly, associated with asthma. This article reviews the findings on the impact of violence on asthma, and the pathways...

Development of simulation package for atomic processes of ultra-large-scale system based on electronic structure theory (2007)

Nitta, Hitoshi, Watanabe, Naoki, Hoshi, Takeo, Fujiwara, Takeo

An early-stage version of simulation package is developed for electronic structure calculation and dynamics of atom process in large-scale systems, particularly, nm-scale or 10nm-scale systems. We...

Two-Stage Formation Model and Helicity of Gold Nanowires (2006)

Iguchi, Yusuke, Hoshi, Takeo, Fujiwara, Takeo

A model for formation of helical multishell gold nanowires is proposed and is confirmed with the quantum mechanical molecular dynamics simulations. The model can explain the magic number of the...

Large-scale electronic structure theory for simulating nanostructure process (2006)

Hoshi, Takeo, Fujiwara, Takeo

Fundamental theories and practical methods for large-scale electronic structure calculations are given, in which the computational cost is proportional to the system size. Accuracy controlling...

Draw out Carbon Nanotube from Liquid Carbon (2006)

Zhang, Shuang, Hoshi, Takeo, Fujiwara, Takeo

Carbon nanotube (CNT) is expected for much more important and broader applications in the future, because of its amazing electrical and mechanical properties. However, today, the prospect is detained...

Activities of Center for Innovation in Engineering Education at the University of Tokyo and Reconstruction Trial of Engineering Education (2006)

Takeo Fujiwara

Though the world-wide academic and industrial circumstances have been changing very rapidly in the last decade, the university system has not well been responding to the changes of external and...

The spread of drug abuse in rapidly urbanizing communities in Vientiane, Lao People's Democratic Republic (2005)

Fujiwara, Takeo, Takano, Takehito, Nakamura, Keiko

SUMMARY To determine the prevalence of drug abuse in city neighborhoods in a developing country undergoing rapid urbanization, we performed a household survey on the spread of drug abuse in...

The spread of drug abuse in rapidly urbanizing communities in Vientiane, Lao People's Democratic Republic (2005)

FUJIWARA, TAKEO, TAKANO, TAKEHITO, NAKAMURA, KEIKO

To determine the prevalence of drug abuse in city neighborhoods in a developing country undergoing rapid urbanization, we performed a household survey on the spread of drug abuse in Vientiane, Lao...

The spread of drug abuse in rapidly urbanizing communities in Vientiane, Lao People's Democratic Republic (2005)

Fujiwara, Takeo, Takano, Takehito, Nakamura, Keiko

SUMMARY To determine the prevalence of drug abuse in city neighborhoods in a developing country undergoing rapid urbanization, we performed a household survey on the spread of drug abuse in...

k-dependent spectrum and optical conductivity near metal-insulator transition in multi-orbital Hubbard bands (2004)

Miura, Oki, Fujiwara, Takeo

We apply the dynamical mean field theory (DMFT) in the iterative perturbation theory(IPT) to doubly degenerate eg bands and triply degenerate tg bands on a simple cubic lattice and calculate the...

Nanoscale structures formed in silicon cleavage studied with large-scale electronic structure alculations; surface reconstruction, step and bending (2004)

Hoshi, Takeo, Iguchi, Yusuke, Fujiwara, Takeo

The 10-nm-scale structure in silicon cleavage is studied by the quantum mechanical calculations for large-scale electronic structure. The cleavage process on the order of 10 ps shows surface...

The electronic structure around As antisite near (110) surface of GaAs (2004)

Iguchi, Yusuke, Fujiwara, Takeo, Hida, Akira, Maeda, Koji

The electronic structure around a single As antisite in GaAs is investigated in bulk and near the surface both in the stable and the metastable atomic configurations. The most characteristic...

Krylov Subspace Method for Molecular Dynamics Simulation based on Large-Scale Electronic Structure Theory (2004)

Takayama, Ryu, Hoshi, Takeo, Fujiwara, Takeo

For large scale electronic structure calculation, the Krylov subspace method is introduced to calculate the one-body density matrix instead of the eigenstates of given Hamiltonian. This method...

Million-atom molecular dynamics simulation by order-N electronic structure theory and parallel computation (2003)

Geshi, Masaaki, Hoshi, Takeo, Fujiwara, Takeo

Parallelism of tight-binding molecular dynamics simulations is presented by means of the order-N electronic structure theory with the Wannier states, recently developed (J. Phys. Soc. Jpn. 69,3773...

Electronic Structure of Transition Metals Fe, Ni and Cu in the GW Approximation (2002)

Yamasaki, Atsushi, Fujiwara, Takeo

The quasiparticle band structures of 3d transition metals, ferromagnetic Fe, Ni and paramagnetic Cu, are calculated by the GW approximation. The width of occupied 3d valence band, which is...

Generalization of the iterative perturbation theory and metal-insulator transition in multi-orbital Hubbard bands (2002)

Fujiwara, Takeo, Yamamoto, Susumu, Ishii, Yasushi

The iterative perturbation theory of the dynamical mean field theory is generalized to arbitrary electron occupation in case of multi-orbital Hubbard bands. We present numerical results of doubly...

Dynamical brittle fractures of nanocrystalline silicon using large-scale electronic structure calculations (2002)

Hoshi, Takeo, Fujiwara, Takeo

A hybrid scheme between large-scale electronic structure calculations is developed and applied to nanocrystalline silicon with more than 10$^5$ atoms. Dynamical fracture processes are simulated under...

Symmetry consideration and eg bands in NdNiO3 and YNiO3 (2001)

Yamamoto, Susumu, Fujiwara, Takeo

Group theoretical analyses are applied to the magnetic and electronic structures of NdNiO3 and YNiO3, whose electronic structures have been studied very recently by the LSDA+U method. The Jahn-Teller...

Electronic structure of the MO oxides (M=Mg, Ca, Ti, V) in the GW approximation (2001)

Yamasaki, Atsushi, Fujiwara, Takeo

The quasiparticle band structures of nonmagnetic monoxides, MO (M=Mg, Ca, Ti, and V), are calculated by the GW approximation. The band gap and the width of occupied oxygen 2p states in insulating MgO...

Charge and orbital order in RNiO3 (R=Nd,Y) by LSDA+U method (2001)

Yamamoto, Susumu, Fujiwara, Takeo

Electronic structure of NdNiO3 and YNiO3 are calculated by using LSDA+U method with rotational invariance. No orbital order on Ni sites is observed in both systems but different charge orderings. In...

Hybridization Mechanism for Cohesion of Cd-based Quasicrystals (2000)

Ishii, Yasushi, Fujiwara, Takeo

Cohesion mechanism of cubic approximant crystals of newly discovered binary quasicrystals, Cd$_6$M (M=Yb and Ca), are studied theoretically. It is found that stabilization due to alloying is obtained...

La 7/8 Sr 1/8 MnO3: long period orbital order with hole stripes (1999)

Korotin, Michael, Fujiwara, Takeo, Anisimov, Vladimir

The electronic structure of La 7/8 Sr 1/8 MnO 3 was studied by using the rotation-invariant LSDA (Local Spin Density Approximation)+U formalism. We found the specific kind of charge and orbital order...

Theory of composite-band Wannier states and order-N electronic-structure calculations (1999)

Hoshi, Takeo, Fujiwara, Takeo

From the order-N electronic-structure formulation, a Hamiltonian is derived, of which lowest eigen state is the generalized or composite-band Wannier state. This Hamiltonian maps the locality of the...

The political and military policies of the Tokugawa Shogunate ... (1934)

Fujiwara, Takeo.

Thesis (M.A.)--Brigham Young University, Dept. of History.