東京大学 · 医学
Sachiko Ono教授の研究室は、酸化アルミナの自己組織化メカニズムに着目し、電流密度と形成電圧の関係がナノポーラス構造の秩序性に与える影響を解明しています。特に、焼け(burning)現象に伴う局所的高電流状態が高秩序なセル配列を誘導するメカニズムを、直接観察を用いて解明しています。また、酸化マグネシウムやα-アルミナ膜のナノ構造制御についても、成長機構と結晶化に伴う微細構造変化を解明しています。
Figures are computed from collected data and may differ slightly.
The controlling factor of self-ordering of anodic porous alumina was investigated by focusing on the current density during film growth. The homogeneity of cell size was improved with increasing formation voltage accompanied by the exponential increase in current density. The maximum anodizing voltage for proceeding uniform oxide growth while avoiding extremely high current accompanied by gas evolution was identical with the previously established self-ordering voltage. With the increase in form
The self-ordering behavior of porous anodic alumina induced by the burning phenomenon on the specimen where extremely high and local current concentrations occurred was studied. The domains of highly self-ordered cell arrangement were found at the locally thickened film formed by burning. At the center of the burnt area, the regularity of cell arrangement was higher and the barrier layer thickness as well as the cell size was remarkably lower. These results clearly suggest that the condition ind
Regulation of blood vessel permeability is essential for the homeostasis of peripheral tissues. This regulation controls the trafficking of plasma contents, including water, vitamins, ions, hormones, cytokines, amyloids, lipoproteins, carrier proteins, and immunoglobulins. The properties of blood vessels vary among tissues based on their structural differences: continuous, fenestrated, or sinusoidal. These three types of blood vessels have different charge and size barrier properties. The anioni
The cylindrical pore structure and barrier layer of anodic films formed on magnesium which are similar to the Keller's model of anodic alumina are determined by direct cross‐sectional observation. The ratios of cell diameter and barrier layer thickness to the forming voltage are notably smaller than those associated with anodic alumina. It is assumed that anodic film growth proceeds mainly by the formation of and (magnesium oxyhydroxide) at the metal/film interface and the dissolution of the fil
Nanoporous and single phase α-alumina membranes with pore diameters tunable over a wide range of approximately 60-350 nm were successfully fabricated by optimizing the conditions for anodizing, subsequent detachment, and heat treatment. The pore diameter increased and the cell diameter shrunk upon crystallization to α-alumina by approximately 20% and 3%, respectively, in accordance with the 23% volume shrinkage resulting from the change in density associated with the transformation from the amor
Thyroid storm is a life-threatening and emergent manifestation of thyrotoxicosis. However, predictive features associated with fatal outcomes in this crisis have not been clearly defined because of its rarity. The objective of this study was to investigate the associations of patient characteristics, treatments, and comorbidities with in-hospital mortality. We conducted a retrospective observational study of patients diagnosed with thyroid storm using a national inpatient database in Japan from
The morphology and the formation behavior of various types of defects in porous anodic films formed on high purity aluminum have been studied by electron microscopy. Circular voids were found within anion‐free layers at the triple polar junctions where three cells met. The voids contained oxide particles which appeared darker in contrast. Crystallization induced by electron beam irradiation initiated around the voids. Long and narrow holes (crack‐like voids) which passed through both anion‐free
The structure and the composition of surface films formed by chemical conversion coating in Dow7 on pure magnesium and magnesium die cast AZ91D have been studied by XRD, XPS, SEM and TEM combined with ultramicrotomy to clarify the growth mechanism. The films are amorphous containing no definite crystallites detectable by XRD . The major constituents of the films are MgF2 and MgOx(OH)y. The content of NaMgF3 increases very much with increasing finishing time. In addition, small amounts of Cr2O3 a
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