http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Strongly correlated electrons on frustrated lattices
Tsunetsugu, H,Hattori, K,Ohashi, T,Kawakami, N,Momoi, T Institute of Physics 2009 Journal of physics. Conference series Vol.145 No.1
<P>We review our two recent theoretical works on strongly correlated electrons on typical frustrated lattices. The first topic is about a Mott transition in the single-band Hubbard model on anisotropic triangular lattice, and we discuss a reentrant behaviour of metal-insulator transition, consistent with that in a κ-type BEDT-TTF salt. The second topic is about heavy fermion behaviour in the vanadium spinel LiV<SUB>2</SUB>O<SUB>4</SUB>. We study the 3-orbital t<SUB>2<I>g</I></SUB> Hubbard model on the pyrochlore lattice at quarter filling and derive its low-energy effective model. The correlations of spin and orbital degrees of freedom are discussed.</P>
HIGH TEMPERATURE STRENGTH OF HYDROGEN ANNEALED SILICON WAFER
Matsushita, J.,Xin, P.,Hayashi, K.,Fujii, O.,Kawamura, N.,Kawakami, T.,Numano, M.,Kubota, H.,Matsushita, Y. 한국재료학회 1995 Fabrication and Characterization of Advanced Mater Vol.1 No.1
High temperature strength of hydrogen annealed silicaon wafer was investiaged. Wafers were 150mm in diameter, Czochralski-grown(100) silicon crystal. Silicon wafers were annealed at $1200^{\circ}C$ for 1 hour in a hydrogen atmosphere with a heating rate of $10^{\circ}C/min$ and $20^{\circ}C/min$ in an hot-wall furnace. Oxygen precipitate density in slow heating rate sample and rapid heating rate sample were $2{\times}10^{9}/cm^3$ and $3{\times}10^{7}/cm^3$, respectively. Decreasing the heating rate increases the oxygen precipitate density. The strength was measured by the three-point bending test at $1000^{\circ}C$ using strip-shpaped samples cult from silicon wafer. The maximum resolved shear stress($T_{max}$) at the specimen surface converted from the maximum load was dependent on strain rate and oxygen precipitate density constained in the silicon wafer. The $T_{max}$, 20.5 MPa for as-received samples, was reduced to 17.9MPa in slow heating rate sample. On the other hand, the $T_{max}$ was almost the same as 20.3 MPa in rapid heating rate sample under a strain rate of $6.9{\times}10^{-6}/s$ at $1000^{\circ}C$.
System Design based on Benefit of Inconvenience and Emotion
H. Kawakami,M. Nishimura,O. Katai,T. Shiose 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
Although the tools of today are developed to be convenient, they do not always satisfy people. Tools sometimes evoke negative feelings in people such that they get tired of using them. In consideration of this fact, to create guidelines for designing tools to make human life richer, this paper focuses on the relationship between the “benefit of inconvenience” and “emotional design.” After referring to their outlines and backgrounds, the discussion about their relationship leads to a proposal of characteristics that are required to be installed to artifacts to enrich human life, and refers to a strategy and applying it to system design theory.
P. G. Gucciardi,R. Micheletto,M. Allegrini,T. Kotani,T. Hatada,Y. Kawakami 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.47 No.1
Distributed Bragg Reflectors (DBRs) have been found to be very effective in increasing the efficiency of light emitting diodes and semiconductor laser devices. By using polarization-modulated scanning near-field optical microscopy (PM-SNOM), we investigate the optical response to different illumination polarization states of a DBR structure that consists of a stack of quarter wavelength thick slabs of dielectrics with alternating high and low refractive index. The DBR has been optically characterized in the near-field at different wavelengths in illumination- and in collection- mode with light excitation orthogonal to the probe axis, for fixed as well as for modulated polarization. We have found that the optical signal does not follow the morphological structure of the slabs, as expected but it shows a different spatial periodicity related to the excitation properties and to the interplay of the different DBR planes.
Yamaguchi, Y.,Nakano, M.,Nagao, H.,Okumura, M.,Yamanaka, S.,Kawakami, T.,Yamaki, D.,Nishino, M.,Shigeta, Y.,Kitagawa, Y.,Takano, Y.,Takahata, M.,Takeda, R. Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.6
A unified picture for magnetism, superconductivity, quantum optics and other properties of molecule-based materials has been presented on the basis of effective model Hamiltonians, where necessary parameter values have been determined by the first principle calculations of cluster models and/or band models. These properties of the matetials are qualitatively discussed on the basis of the spin and pseudo-spin Hamiltonian models, where several quantum operators are expressed by spin variables under the two level approximation. As an example, ab initio broken-symmetry DFT calculations are performed for cyclic magnetic ring constructed of 34 hydrogen atoms in order to obtain effective exchange integrals in the spin Hamiltonian model. The natural orbital analysis of the DFT solution was performed to obtain symmetry-adapted molecular orbitals and their occupation numbers. Several chemical indices such as information entropy and unpaired electron density were calculated on the basis of the occupation numbers to elucidate the spin and pair correlations, and bonding characteristic (kinetic correlation) of this mesoscopic magnetic ring. Both classical and quantum effects for spin alignments and singlet spin-pair formations are discussed on the basis of the true spin Hamiltonian model in detail. Quantum effects are also discussed in the case of superconductivity, atom optics and quantum optics based on the pseudo spin Hamiltonian models. The coherent and squeezed states of spins, atoms and quantum field are discussed to obtain a unified picture for correlation, coherence and decoherence in future materials. Implications of theoretical results are examined in relation to recent experiments on molecule-based materials and molecular design of future molecular soft materials in the intersection area between molecular and biomolecular materials.