名古屋大学 · 工学
石川賢治教授の研究室は、酸化物半導体やペロブスカイト系材料を対象に、ナノスケールにおける相転移や表面状態の制御を原子レベルで解明する研究を行っています。特に、PbTiO₃やBaTiO₃の微粒子におけるサイズ効果や表面格子緩和がフェロエレクトリック性に与える影響を、X線回折やラマン分光を用いて精密に分析しています。また、がん幹細胞の起源やがん関連タンパク質の機能解明にも関心を持ち、臨床的意義のある材料科学とバイオメディスンの融合的研究を推進しています。
Figures are computed from collected data and may differ slightly.
We report a size effect on the ferroelectric phase transition in ${\mathrm{PbTiO}}_{3}$ ultrafine particles. The samples were synthesized by an alkoxide method. The size was determined by x-ray analysis with the aid of Scherrer's equation. When the particle size is less than 50 nm, the transition temperature ${T}_{c}$, determined by Raman scattering, decreases from its bulk value (500 \ifmmode^\circ\else\textdegree\fi{}C) as the size decreases. The temperature ${T}_{c}$ is described by an empiri
Lattice relaxation on the surface of ${\mathrm{PbTiO}}_{3}$ and ${\mathrm{BaTiO}}_{3}$ is investigated under the assumption that the spurious lattice expansion in perovskite nanocrystals is caused by the surface relaxation. By comparing the observed peak position and full width at half maximum with those of the calculated x-ray diffraction patterns from a cubic lattice containing surface relaxation, the maximum relaxation on the surface of ${\mathrm{PbTiO}}_{3}$ is found to be 0.035 nm, and 0.01
In this review, we discuss the progress of emerging dry processes for nanoscale fabrication of high-aspect-ratio features, including emerging design technology for manufacturability. Experts in the fields of plasma processing have contributed to addressing the increasingly challenging demands of nanoscale deposition and etching technologies for high-aspect-ratio features. The discussion of our atomic-scale understanding of physicochemical reactions involving ion bombardment and neutral transport
Mitotic centromere-associated kinesin (MCAK) is a microtubule depolymerase that is essential for proper kinetochore-microtubule attachment during spindle formation. Overexpression of MCAK has been correlated with aggressive forms of carcinoma, resulting in poor prognosis of colorectal cancer. The purpose of this study was to quantify MCAK expression in malignant and benign colorectal tissues and to determine if MCAK expression levels correlate with clinicopathologic factors and prognosis in colo
The finite size effect on the phase transition in PbTiO 3 fine particles is described. Very small crystals with an average diameter of 14.2 nm were obtained by lowering the calcination temperature to 400° C. Raman scattering measurements of such fine particles were carried out to study the dependence of the phase transition temperature on the particle size. The X-ray diffraction pattern was also measured to study the tetragonality, c / a ratio. The results strongly suggest the presence of a crit
Recent evidence suggests that some cancers may originate from cancer stem cells, which may derive from carcinogenesis of normal stem cells. A hepatic progenitor cell population, which gives rise to hepatocytes and cholangiocytes, has been suggested in humans, though whether these cells can give rise to malignant tumors has not been confirmed. We report here a case of an alpha-fetoprotein (AFP)-producing intrahepatic cholangiocarcinoma (ICC) in an 81-year-old woman with chronic hepatitis C viral
In this review, we discuss the progress of emerging dry processes for nanoscale fabrication. Experts in the fields of plasma processing have contributed to addressing the increasingly challenging demands in achieving atomic-level control of material selectivity and physicochemical reactions involving ion bombardment. The discussion encompasses major challenges shared across the plasma science and technology community. Focus is placed on advances in the development of fabrication technologies for
Open papers in the app to read, cite, and organize with AI.