On the Phononic Bandgap of Carbon Nanotubes

On the phononic bandgap of carbon nanotubes (CNTs), we show in what chirality CNTs have phononic bandgaps and its dependence on the diameters of CNTs. We find that, though the rule where CNTs have phononic bandgaps is the same as in the electronic structure case, the diameter dependence is different. The phononic bandgaps of the zigzag-CNTs reveal “three” kinds of diameter dependence due to the anisotropy of graphene phonon band around the K point in k-space. We also show the crossover from one- to two-dimensional characteristics in phononic bandgaps

Electoronic structure of twofold-coordinated atoms in silicon-based amorphous semiconductors

Electronic states of the twofold-coordinated N atom in a-SixNi1-x:H and twofold-coordinated P atom in P-doped a-Si:H have been calculated using the density-functional theory with a local-spin-density approximation. The calculated 14N hyperfine parameters agree fairly well with those observed in N-rich a-SixN1-x:H by electron-spin-resonance (ESR) experiments, confirming the ESR center to be a twofold-coordinated N atom. On the other hand, the calculated 31P hyperfine parameters are largely different from the observed values for the ESR center with a 250-G splitting in P-doped a-Si:H. Therefore the ESR center should not be identified as a twofold-coordinated P atom

Origin of the ESR signal with g=2.0055 in amorphous silicon

Defect-state wave functions for threefold- and fivefold-coordinated Si atoms in amorphous silicon clusters have been calculated with use of a first-principles linear combination of the atomic orbitals method in order to clarify the origin of the ESR signal with g=2.0055 in amorphous silicon. The wave function of the defect state originating from the threefold-coordinated Si atom is strongly localized on this atom. On the other hand, that for the fivefold-coordinated Si atom is extended on this atom and its nearest neighbors. By comparing these results with the observed hyperfine structure of the ESR signal, we conclude that the origin of this ESR signal is the threefold-coordinated Si atoms

An initio calculations for defects in silicon-based amorphous semiconductors

We have calclulated the ESR hyperfine parameters of threefold-coordinated Si atoms and twofold-coordinated P and N atoms in Si-based amorphous semiconductors using the density functional theory with a local-spin-density approximation. These calculated results have been compared with the observed ESR results

<ORIGINAL ARTICLE>The effects of sagittal ramus osteotomy for mandibular prognathism on maximum mouth opening and condylar movement

Maximum mouth opening and condylar movement before and more than 6 months after surgery were analyzed in 23 cases of sagittal ramus osteotomy of the mandible for correction of mandibular prognathism. Condylar movement (translation and rotation) did not show postoperatively a significant difference pre-and postoperatively, and then was a tendency to a reduction of maximum mouth opening was found

Charge transport calculations by a wave-packet dynamical approach using maximally localized Wannier functions based on density functional theory: Application to high-mobility organic semiconductors

We present a wave-packet dynamical approach to charge transport using maximally localized Wannier functions based on density functional theory including van der Waals interactions. We apply it to the transport properties of pentacene and rubrene single crystals and show the temperature-dependent natures from bandlike to thermally activated behaviors as a function of the magnitude of external static disorder. We compare the results with those obtained by the conventional band and hopping models and experiments

Complications of mandibular sagittal split osteotomy for correction of mandibular prognathism

Sagittal split ramus osteotomy is most frequently performed to correct mandibular prognathism. In this study, intra- and postoperative complications were evaluated in 92 patients treated with this technique. Intraoperative complications occurred in 6 cases (6.5%) of the cases. In addition to experience and skill, complications appeared related to the design of the osteotomy and to attention to detail during the operation. Neurological damage following the sagittal split ramus osteotomy is a common complication after the surgery. Here, sensory disturbance was observed in 63 cases (68.5%) several days after the operation, and in 21 cases (22.8%) at 6 months, 8 cases (8.7%) at one year, 5 cases (5.4%) at 2 years, and 3 cases (3.3%) at 3 years. It was suggested that nerve damage is closely related to the degree of strain and compression of the inferior alveolar nerve