The University of Tokyo · 재료과학
이 교수의 연구실은 주로 금속 합금의 복잡한 구조, 특히 고체 상태에서의 원자 배열과 상전이를 연구합니다. 특히 마그네슘 기반 합금의 다형성과 긴 주기적 배열을 가진 구조, 그리고 퀀티크리스탈(비정질 구조)의 원자적 기초를 규명하는 데 초점을 맞추고 있습니다. 전자현미경 및 원자 해상도 이미징 기법을 활용해 원자 배열과 화학적 순서의 상호관계를 규명하며, 새로운 상 구조의 기원과 안정성에 대한 통찰을 제공합니다.
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A series of structural polytypes formed in an Mg–1 at.%Zn–2 at.%Y alloy has been identified, which are reasonably viewed as long-period stacking derivatives of the hexagonal-close-packed Mg structure with alternate AB stacking of the close-packed atomic layers. Atomic-resolution Z-contrast imaging clearly revealed that the structures are long-period chemical-ordered as well as stacking-ordered; unique chemical order along the stacking direction occurs as being synchronized with a local faulted s
We present new evidence supporting the quasi-unit-cell description of the Al72Ni20Co8 decagonal quasicrystal which shows that the solid is composed of repeating, overlapping decagonal cluster columns with broken tenfold symmetry. We propose an atomic model which gives a significantly improved fit to electron microscopy experiments compared to a previous proposal by us and to alternative proposals with tenfold symmetric clusters.
Study Design. The surface strain distribution on the thoracic and lumbar vertebrae during axial compressive loading was examined. Objectives. To examine the general mechanical behavior of the thoracic and lumbar vertebrae to evaluate their role in burst fractures. Summary of Background Data. Burst fractures are generally characterized by injury to the middle column and fracturing of the superior endplate. However, results in previous biomechanical investigations have not shown how these fracture
The records of 14 patients with malignant or aggressive benign vertebral tumors of the thoracolumbar spine who underwent total spondylectomy (TS) were evaluated retrospectively. Total spondylectomy was performed by bisecting the affected vertebra through the pedicle using fine threadwire saws and removing the vertebra en bloc through the posterior procedure alone or the one-stage anteroposterior combined procedure. Remarkable pain relief and ambulation after surgery were achieved in all 14 patie
Selective radiculography was the method of examination with the optimal diagnostic value for far-out foraminal stenosis. An anterior approach to the decompression of far-out foraminal stenosis below a lumbosacral transitional vertebra is a relatively simple and effective method.
We report a reversible phase transformation between the icosahedral Zn-Mg--rare-earth(RE) quasicrystal and the hexagonal crystal being not composed of any giant icosahedral atomic cluster. This clearly shows that the large atomic cluster is not an essential atomic configuration for quasicrystal formation. A structural unit of the Zn-Mg-RE icosahedral quasicrystal is suggested to be not an icosahedral atomic cluster such as the Mackay or Bergman type which have been successfully used for the stru
We have investigated thermodynamic behaviors of dilute Mg-Zn-Y ternary alloys to form a unique solute-enriched stacking-fault (SESF), which is an intrinsic-II type stacking-fault (I2-SF) enriched by the Zn and Y atoms and represents the structural-unit of the long-period stacking/order (LPSO) phase. SESF in the hexagonal-close-packed (hcp) Mg matrix forms a local face-centered-cubic (fcc) environment, and hence our thermodynamic analysis is based on the Gibbs energy comparison between hcp and fc
We have investigated short-range order (SRO) solute clusters in the long-period stacking/order (LPSO) phases with an intrinsic-I (I1) type stacking faults (SFs), which have been uniquely formed in Mg-Co-Y alloys, based on atomic-resolution scanning transmission electron microscopy (STEM) combined with first-principles calculations. The Co3Y5 SRO cluster model embedded across the I1-type SFs has been successfully constructed to satisfy the observed electron diffraction, STEM images and computed e