1,769 research outputs found
Alkaline phosphatase encapsulated in gellan-chitosan hybrid capsules
This is a preprint of an article published in [Fujii, T; Ogiwara, D; Ohkawa, K; Yamamoto, H.,Alkaline phosphatase encapsulated in gellan-chitosan hybrid capsules,MACROMOLECULAR BIOSCIENCE,Vol 5,394-400(2005)]ArticleMACROMOLECULAR BIOSCIENCE. 5(5): 394-400 (2005)journal articl
A novel human hair protein fiber prepared by watery hybridization spinning
This is a preprint of an article published in [Hirao, Y; Ohkawa, K; Yamamoto, H; Fujii, T.,A novel human hair protein fiber prepared by watery hybridization spinning,MACROMOLECULAR MATERIALS AND ENGINEERING,Vol 290,165-171(2005)]ArticleMACROMOLECULAR MATERIALS AND ENGINEERING. 290(3): 165-171 (2005)journal articl
Low Temperature Properties of Quantum Antiferromagnetic Chains with Alternating Spins S=1 and 1/2
We study the low-temperature properties of S=1 and 1/2 alternating spin
chains with antiferromagnetic nearest-neighbor exchange couplings using
analytical techniques as well as a quantum Monte Carlo method. The spin-wave
approach predicts two different low-lying excitations, which are gapped and
gapless, respectively. The structure of low-lying levels is also discussed by
perturbation theory in the strength of the Ising anisotropy. These analytical
findings are compared with the results of quantum Monte Carlo calculations and
it turns out that spin-wave theory well describes the present system. We
conclude that the quantum ferrimagnetic chain exhibits both ferromagnetic and
antiferromagnetic aspects.Comment: 13 pages, RevTeX, six figures, submitted to J. Phys. Cond. Ma
Elementary Excitations of Heisenberg Ferrimagnetic Spin Chains
We numerically investigate elementary excitations of the Heisenberg
alternating-spin chains with two kinds of spins 1 and 1/2 antiferromagnetically
coupled to each other. Employing a recently developed efficient Monte Carlo
technique as well as an exact diagonalization method, we verify the spin-wave
argument that the model exhibits two distinct excitations from the ground state
which are gapless and gapped. The gapless branch shows a quadratic dispersion
in the small-momentum region, which is of ferromagnetic type. With the
intention of elucidating the physical mechanism of both excitations, we make a
perturbation approach from the decoupled-dimer limit. The gapless branch is
directly related to spin 1's, while the gapped branch originates from
cooperation of the two kinds of spins.Comment: 7 pages, 7 Postscript figures, RevTe
Magnetization cusp singularities of frustrated Kondo necklace model
Magnetization processes of frustrated Kondo necklace model are studied by
means of a density matrix renormalization group (DMRG) method and an elementary
band theory based on a bond-operator formalism. The DMRG calculations clearly
show the cusp singularity in a low-magnetization region () besides
that in a high-magnetization region () which is expected from previous
studies on the magnetization curve of the Majumdar-Ghosh model. An appearance
mechanism of the low-magnetization cusp is interpreted in terms of a
double-well shape of a low-energy band arising from frustrations between
nearest- and next-nearest-neighbor interactions. We also discuss critical
behaviors of magnetization near the cusp and obtain a phase diagram showing
whether the cusp appears in the magnetization curve or not.Comment: 8 pages, 7 figures. to be published in J. Phys. Soc. Jp
- …