Coupled Vortex Dynamics in Permalloy Submicron Disk Pairs

Satoshi Sugimoto,Yasuhiro Fukuma,Shinya Kasai,Yoshi Chika Otani 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12

Coexistence between Zostera marina and Zostera japonica in seagrass beds of the Seto Inland Sea, Japan

Sugimoto, Kenji,Nakano, Yoichi,Okuda, Tetsuji,Nakai, Satoshi,Nishijima, Wataru,Okada, Mitsumasa The Ecological Society of Korea 2017 Journal of Ecology and Environment Vol.41 No.3

Background: There have been many studies on the growth conditions of Zostera marina and Zostera japonica, but few studies have examined how spatial and temporal factors affect growth in established seagrass beds or the distribution range and shoot density. This study aims to clarify the factors that determine the temporal and spatial distribution of Zostera marina and Zostera japonica in the Seto Inland Sea east of Yamaguchi Prefecture. Methods: The study site is in Hiroshima Bay of the Seto Inland Sea, along the east coast of Yamaguchi Prefecture, Japan. We monitored by diving observation to confirm shoot density, presence or absence of both species and observed water temperature, salinity by sensor in study sites. Results: The frequency of occurrence of Zostera marina was high in all seasons, even in water depths of D.L. + 1 to -5 m ($80{\pm}34%$ to $89{\pm}19%$; mean ${\pm}$ standard deviation), but lower (as low as $43{\pm}34%$) near the breakwall, where datum level was 1 to 2 m, and it was further reduced in datum level -5 m and deeper. The frequency of occurrence of Zostera japonica was highest in water with a datum level of +1 to 0 m. However, in datum level of 0 m or deeper, it became lower as the water depth became deeper. Datum level +1 m to 0 m was an optimal water depth for both species. The frequency of occurrence and the shoot density of both species showed no negative correlation. In 2011, the daily mean water temperature was $10^{\circ}C$ or less on more days than in other years and the feeding damage by S. fuscescens in the study sites caused damage at the tips. Conclusions: We considered that the relationship between these species at the optimal water depth was not competitive, but due to differences in spatial distribution, Zostera marina and Zostera japonica do not influence each other due to temperature conditions and feeding damage and other environmental conditions. Zostera japonica required light intensity than Zostera marina, and the water depth played an important role in the distribution of both species.

SiC nanowires formed by high energy ion beam irradiation to polymer films and heating

Satoshi Tsukuda,Shu Seki,Masaki Sugimoto,Seiichi Tagawa,Shun-Ichiro Tanaka 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.5

Ion bombardment can release densely active intermediates within a cylindrical area along the passage of a single ion. The cylindrical area, in which high-energy is deposited from projectile ion, is sometimes called an “ion track”. The high energy charged particle irradiation of a polycarbosilane (PCS) film causes cross-linking reactions, leading to the formation of a polymer gel containing cylindrical nanostructures (nanowires). The diameter and length of the nanowires were completely controlled by changing several parameters. PCS is also a well-known a precursor of silicon carbide (SiC), and the PCS nanowires formed by the present techniques were heated at 1,000 oC in Ar gas. A SiC ceramic wire, which has a higher heat resistance than polymers, was obtained on a Si substrate by conversion from the PCS nanowires. In this paper, the crystal structure and phase of the SiC nanowires obtained are discussed. Ion bombardment can release densely active intermediates within a cylindrical area along the passage of a single ion. The cylindrical area, in which high-energy is deposited from projectile ion, is sometimes called an “ion track”. The high energy charged particle irradiation of a polycarbosilane (PCS) film causes cross-linking reactions, leading to the formation of a polymer gel containing cylindrical nanostructures (nanowires). The diameter and length of the nanowires were completely controlled by changing several parameters. PCS is also a well-known a precursor of silicon carbide (SiC), and the PCS nanowires formed by the present techniques were heated at 1,000 oC in Ar gas. A SiC ceramic wire, which has a higher heat resistance than polymers, was obtained on a Si substrate by conversion from the PCS nanowires. In this paper, the crystal structure and phase of the SiC nanowires obtained are discussed.

Coexistence between Zostera marina and Zostera japonica in seagrass beds of the Seto Inland Sea, Japan

Kenji Sugimoto,Yoichi Nakano,Tetsuji Okuda,Satoshi Nakai,Wataru Nishijima,Mitsumasa Okada 한국생태학회 2017 Journal of Ecology and Environment Vol.41 No.3

Background: There have been many studies on the growth conditions of Zostera marina and Zostera japonica, but few studies have examined how spatial and temporal factors affect growth in established seagrass beds or the distribution range and shoot density. This study aims to clarify the factors that determine the temporal and spatial distribution of Zostera marina and Zostera japonica in the Seto Inland Sea east of Yamaguchi Prefecture. Methods: The study site is in Hiroshima Bay of the Seto Inland Sea, along the east coast of Yamaguchi Prefecture, Japan. We monitored by diving observation to confirm shoot density, presence or absence of both species and observed water temperature, salinity by sensor in study sites. Results: The frequency of occurrence of Zostera marinawas high in all seasons, even in water depths of D.L. + 1 to −5 m (80 ± 34% to 89 ± 19%; mean ± standard deviation), but lower (as low as 43 ± 34%) near the breakwall, where datum level was 1 to 2 m, and it was further reduced in datum level −5 m and deeper. The frequency of occurrence of Zostera japonica was highest in water with a datum level of +1 to 0 m. However, in datum level of 0 m or deeper, it became lower as the water depth became deeper. Datum level +1 m to 0 m was an optimal water depth for both species. The frequency of occurrence and the shoot density of both species showed no negative correlation. In 2011, the daily mean water temperature was 10 °C or less on more days than in other years and the feeding damage by S. fuscescens in the study sites caused damage at the tips. Conclusions: We considered that the relationship between these species at the optimal water depth was not competitive, but due to differences in spatial distribution, Zostera marina and Zostera japonica do not influence each other due to temperature conditions and feeding damage and other environmental conditions. Zostera japonica required light intensity than Zostera marina, and the water depth played an important role in the distribution of both species.

Microwave Absorption Properties of Polymer Composites with Amorphous Fe-B and Ni-Zn-Co Ferrite Nanoparticles

Kazuaki Shimba,Shozo Yuki,Nobuki Tezuka,Satoshi Sugimoto 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12

Nowadays, many communication devices use GHz-range microwaves, which cause serious issues,such as electromagnetic interference. For the prevention of these problems, microwave absorbersconsisting of polymer composites with magnetic particles have received attention. With the currenttrend being to miniaturize devices, thin microwave absorber are now required. This paperreports that polymer composites with amorphous Fe-B submicrometer particles and Ni-Zn-Co ferritenanoparticles showed a permeability of µ0r = 8.0-9.0 at 1.0 GHz and a resonant frequency of fr= 1.8 - 2.4 GHz. They also exhibited good microwave absorption properties at 0.7 - 1.4 GHz forthicknesses of 2.5 - 3.9 mm.

Development of Powdered Soft Magnetic Material Suitable for Electric Devices Operating at High Frequencies

Ishimine Tomoyuki,Maeda Toru,Toyoda Haruhisa,Mimura Kouji,Nishioka Takao,Sugimoto Satoshi 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Recently, there has been a growing demand for soft magnetic materials with high conversion characteristics, due to the trend of electric devices to higher-frequency range. For ruduceing core loss in the high-frequency range, using finely grained and high-resistivity Fe-based alloy powder is most efficient methods. But, conventionally, there's been a compressibility problem for such powder. In this work, Fe-based alloy powder that offers both high resistivity and high compressibility was developed by studyuing composition of the powder, and reduction of core loss of P/M soft magnetic materials in the high frequency range was achieved.

Visualized experimental investigation on the hydraulic characteristics of two-phase flow in a single smooth and single rough rock fractures

Chen Wang,Yujing Jiang,Jiankang Liu,Changsheng Wang,Satoshi Sugimoto 한국지질과학협의회 2021 Geosciences Journal Vol.25 No.3

In present engineering applications, calculations of hydraulic properties in two-phase flow are still highly dependent on empirical or semi-empirical equations obtained from experiments. However, the empirical equations that can reproduce the experiment data on a certain fracture specimen may have errors on other specimens. Researchers have obtained results that show quite different evolution forms of hydraulic characteristics of two-phase flow, which is induced by the variety of the influencing factors in two-phase flow. This paper aims at expanding the experimental results on the hydraulic characteristics of two-phase flow in rock fractures. With a newly developed experiment system, visualized two-phase flow experiments were introduced. The difference in the surface morphology of the fractures leads to totally different flow structures, which indicates the role of capillary pressure differs due to different fracture surfaces. The relative permeability in the rough specimen approximately follows the Corey model, which confirmed that the pressure drop is in this rough fracture is dominated by the capillary pressure, but the relative permeability is not only the function of saturation, but also the function of water flow velocities. However, the relative permeability is not perfect for evaluating the difference of two-phase hydraulic characteristics induced by the fracture surface morphology. On the contrary, the Lockhart-Martinelli model is appropriate for evaluating the difference in the two-phase hydraulic characteristics between the smooth fracture and the rough fracture, which indicates that the two-phase flow turbulence is obviously increased by the fracture roughness.

Mechanism of shear deformation, failure and energy dissipation of artificial rock joint in terms of physical and numerical consideration

Xuepeng Zhang,Yujing Jiang,Gang Wang,Jiankang Liu,Dong Wang,Changsheng Wang,Satoshi Sugimoto 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.3

The physical and mechanical change processes of rock are closely related to energy transformation, and its deformation and failure is an instability phenomena driven by energy exchange. This study investigated mechanism of shear deformation, failure and energy dissipation of joint using both physical and numerical direct shear tests under constant normal load (CNL) condition. Three kinds of joint surface were artificially prepared. An acoustic emission system was employed to monitor acoustic emission in physical test, and rupture frequency was recorded in numerical test to represent micro-crack development. By research of numerical micro-crack development accompanied with physical acoustic emission results, mechanism of shear deformation and failure of joints were illustrated schematically. By definition of dissipation energy, captured using the particle flow code (PFC2D), energy releasing and dissipation were discussed with microscopic damage evolution of joints. Results showed that joints under shearing present a dissipation trend of four stages including a slow rise stage, a rapid rise stage, a shock rise stage and a rapid decline stage.

Long-Term Survival after Stroke in 1.4 Million Japanese Population: Shiga Stroke and Heart Attack Registry

Naoyuki Takashima,Hisatomi Arima,Yoshikuni Kita,Takako Fujii,Sachiko Tanaka-Mizuno,Satoshi Shitara,Akihiro Kitamura,Yoshihisa Sugimoto,Makoto Urushitani,Katsuyuki Miura,Kazuhiko Nozaki 대한뇌졸중학회 2020 Journal of stroke Vol.22 No.3

Background and Purpose Although numerous measures for stroke exist, stroke remains one of the leading causes of death in Japan. In this study, we aimed to determine the long-term survival rate after first-ever stroke using data from a large-scale population-based stroke registry study in Japan. Methods Part of the Shiga Stroke and Heart Attack Registry, the Shiga Stroke Registry is an ongoing population-based registry study of stroke, which covers approximately 1.4 million residents of Shiga Prefecture in Japan. A total 1,880 patients with non-fatal first-ever stroke (among 29-day survivors after stroke onset) registered in 2011 were followed up until December 2016. Five-year cumulative survival rates were estimated using the Kaplan-Meier method, according to subtype of the index stroke. Cox proportional hazards models were used to assess predictors of subsequent allcause death. Results During an average 4.3-year follow-up period, 677 patients died. The 5-year cumulative survival rate after non-fatal first-ever stroke was 65.9%. Heterogeneity was present in 5-year cumulative survival according to stroke subtype: lacunar infarction, 75.1%; large-artery infarction, 61.5%; cardioembolic infarction, 44.9%; intracerebral hemorrhage, 69.1%; and subarachnoid hemorrhage, 77.9%. Age, male sex, Japan Coma Scale score on admission, and modified Rankin Scale score before stroke onset were associated with increased mortality during the chronic phase of ischemic and hemorrhagic stroke. Conclusions In this study conducted in a real-world setting of Japan, the 5-year survival rate after non-fatal first-ever stroke remained low, particularly among patients with cardioembolic infarction and large-artery infarction in the present population-based stroke registry.