Numerical Simulation On Spatial Development Processes Of Roll Waves In A Steep Channel

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Microscopic Observation of Tensile Deformation Behavior of Polycrystalline Titanium with Scanning Probe Microscope

The change in the surface morphology of polycrystalline titanium during tensile plastic deformation is studied, using the scanning probe microscope as well as the laser scanning microscope. The observation shows that the slip occurs mainly near grain boundary at the strain range of ε < 0.05. The slip develops with the applied strain, and the slip on the second slip system or the crossing of slip lines appear. The surface roughness increases linearly with the applied strain. The height difference between the grain boundary area and the inner grain area also increases with the applied strain, though the increase rate becomes low after the applied strain of about 0.3. The nano-scale height difference of the surface step of slip lines increases with the applied strain, though it remains almost constant after the applied strain of 0.4. The averaged surface roughness measured with the scanning probe microscope is in good agreement with that measured with the laser scanning microscope

Real-space observation of short-period cubic lattice of skyrmions in MnGe

Emergent phenomena and functions arising from topological electron-spin textures in real space or momentum space are attracting growing interest for new concept of states of matter as well as for possible applications to spintronics. One such example is a magnetic skyrmion, a topologically stable nanoscale spin vortex structure characterized by a topological index. Real-space regular arrays of skyrmions are described by combination of multi-directional spin helixes. Nanoscale configurations and characteristics of the two-dimensional skyrmion hexagonal-lattice have been revealed extensively by real-space observations. Other three-dimensional forms of skyrmion lattices, such as a cubic-lattice of skyrmions, are also anticipated to exist, yet their direct observations remain elusive. Here we report real-space observations of spin configurations of the skyrmion cubic-lattice in MnGe with a very short period (~3 nm) and hence endowed with the largest skyrmion number density. The skyrmion lattices parallel to the {100} atomic lattices are directly observed using Lorentz transmission electron microscopes (Lorentz TEMs). It enables the first simultaneous observation of magnetic skyrmions and underlying atomic-lattice fringes. These results indicate the emergence of skyrmion-antiskyrmion lattice in MnGe, which is a source of emergent electromagnetic responses and will open a possibility of controlling few-nanometer scale skyrmion lattices through atomic lattice modulations

歴史なき人びとの歴史実践 : ホンジュラスの逃亡奴隷ガリフナ

学位の種別: 論文博士審査委員会委員 : （主査）東京大学教授 石橋 純, 東京大学教授 名和 克郎, 東京大学准教授 受田 宏之, 東京大学名誉教授 木村 秀雄, 東京外国語大学教授 鈴木 茂University of Tokyo(東京大学

B20型化合物における電子・スピン構造と電荷・熱輸送現象

学位の種別:課程博士University of Tokyo(東京大学

Giant geometry modulation on magnetic proximity effect observed in isomeric oxide heterostructures

Magnetic proximity effect (MPE) is generally considered to occur at the magnetic-nonmagnetic material interface within a short-range space domain, while the structural geometry modulation on such an interface effect has not been explored. Here, we fabricate isomeric paramagnetic metallic IrO2 with rutile and anatase structures, respectively, on a ferrimagnetic insulating CoFe2O4, and study the MPE-induced magnetism by anomalous Hall effect (AHE) measurements. The rutile phase with layered structure shows a conventional AHE and identical coercive-field with CoFe2O4, indicating a concomitant magnetic switching as a result of a strong magnetic coupling at the interface. In contrast, the anatase phase with tetrahedral structure exhibits an unconventional AHE with negative coercive-field at low temperatures. Further analyses indicate that in anatase, the contribution that strongly couples with CoFe2O4 is dramatically suppressed while a giant frustration-like response emerges. Our findings reveal that the MPE-induced spin orders can be pronouncedly modulated by structural geometry

The Protective Effects of Ultraviolet A1 Irradiation on Spontaneous Lupus Erythematosus-Like Skin Lesions in MRL/lpr Mice

We investigated the effects of ultraviolet A1 (UVA1) irradiation on spontaneous lupus erythematosus- (LE-) like skin lesions of MRL/lpr mice, using a disease prevention model. UVA1 irradiation significantly inhibited the development of LE-like skin lesions, without obvious changes of the disease including renal disease and serum antinuclear antibody levels. Besides the massive infiltration of mast cells in the LE-like skin lesions, in the nonlesional skins, more mast cells infiltrated in the UVA1-irradiated group compared with the nonirradiated group. Although apoptotic cells were remarkably seen in the dermis of UVA1-irradiated mice, those cells were hardly detectable in the dermis of the nonirradiated mice without skin lesions. Further analysis showed that some of those apoptotic cells were mast cells. Thus, UVA1 might exert its effects, at least in part, through the induction of the apoptosis of pathogenic mast cells. Our results supported the clinical efficacy of UVA1 irradiation for skin lesions of lupus patients