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Your search keyword '"Koyama, Yuka"' showing total 29 results
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29 results on '"Koyama, Yuka"'

2. Fatigue strength improvement of aluminum alloy with surface defect by ball burnishing.

Author

Wakamatsu, Kohei, Takahashi, Koji, Koyama, Yuka, and Taniguchi, Masanori

Subjects
FATIGUE limit, ALUMINUM alloy fatigue, SURFACE defects, FRACTURE mechanics, RESIDUAL stresses
Abstract

Ball burnishing (BB) is a surface finishing process that involves moving the tool while pressing it against the workpiece under rolling contact. We investigated the effects of BB on the fatigue strength of an aluminum alloy with a semicircular slit simulating an initial surface defect. After performing BB under a typical condition, compressive residual stress was induced to a depth of 0.4 mm, with a reduction in surface roughness by 81%. Consequently, the fatigue strength increased by 22%. BB prevented the fatigue strength reduction caused by the 0.1 mm deep slit. The result indicated that BB could render the below 0.1 mm deep surface defect harmless in terms of fatigue strength. The maximum depth of surface defect that can be rendered harmless is 0.18 mm according to fracture mechanics, which is in agreement with the experimental results. Highlights: Ball burnishing (BB) can introduce large compressive residual stress along with smoothing.BB can render a 0.1 mm deep slit harmless in terms of fatigue strength.Defect size rendered harmless can be estimated based on fracture mechanics.Compressive residual stress is the main factor rendering the surface defect harmless. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Multivalent DNA and nucleosome acidic patch interactions specify VRK1 mitotic localization and activity

Author

Budziszewski, Gabrielle R, primary, Zhao, Yani, additional, Spangler, Cathy J, additional, Kedziora, Katarzyna M, additional, Williams, Michael R, additional, Azzam, Dalal N, additional, Skrajna, Aleksandra, additional, Koyama, Yuka, additional, Cesmat, Andrew P, additional, Simmons, Holly C, additional, Arteaga, Eyla C, additional, Strauss, Joshua D, additional, Kireev, Dmitri, additional, and McGinty, Robert K, additional

Published
2022
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9. Taxation on Qualitatively Divided Beneficial Interests in Monetary Claim Trust : Meaning of 'Beneficiary' under Article 12 of Corporation Tax Act

Author

Koyama, Yuka

Abstract

本論文は、資産の流動化取引のうち、特に信託を利用した金銭債権の流動化取引において、質的に分割された受益権に関する課税上の問題について考察を行ったものである。 信託に関する税務上の規律として、法人税法12条1項本文は、私法上は受託者が信託財産を有しているにもかかわらず、受益者が信託財産に属する資産及び負債を有するものとみなし、かつ、当該信託財産に帰せられる収益及び費用は当該受益者の収益及び費用とみなすことを定めているが、優先受益権や劣後受益権といった形で、異質かつ複数の受益権を複数の受益者が保有している場合、受益者がどのような割合で信託財産を保有しているとするのかについては判然とせず、法人税法12条1項本文を素直に適用することができない。これは法人税法12条1項本文の「受益者」の意義が判然としない点に起因するものといえる。 そこで、本論文では、当該「受益者」の意義及び同項本文の「受益者」に該当するか否かの判断基準を提示し、受益権が質的に分割された金銭債権信託に関する課税関係を明らかにする。

Published
2019

20. Impact of Hands-on Experience of a Cadaver Dissection on the Professional Identity Formation of Health Sciences Students

Author

Miyoshi, Masayuki, Mori, Tetsuji, Tanimura, Chika, Nakane, Hironobu, Mukuda, Takao, Okazaki, Kenji, Koyama, Yuka, Hanaki, Keiichi, Nakano, Toshiya, Kaidoh, Toshiyuki, Miyoshi, Masayuki, Mori, Tetsuji, Tanimura, Chika, Nakane, Hironobu, Mukuda, Takao, Okazaki, Kenji, Koyama, Yuka, Hanaki, Keiichi, Nakano, Toshiya, and Kaidoh, Toshiyuki

Abstract

[Background] In Japan, some nursing and health science universities that train nurses and/or clinical laboratory technicians have a curriculum in which students observe medical students performing a cadaver dissection. Observing a cadaver dissection is believed to affect the formation of a student’s professional identity. This study aimed to investigate the effects of observing a cadaver dissection on the professional identity of nursing and clinical laboratory science students to find an effective educational support system for developing professional identity. [Methods] Sophomores majoring in nursing science or clinical laboratory science were asked to complete a questionnaire with a professional identity scale before and after hands-on experience of a cadaver dissection performed by medical students. After their hands-on session was complete, they responded to a free-answer question about acquiring a professional identity. [Results] The professional identity score of nursing students significantly decreased after the hands-on experience of the cadaver dissection. No significant change in professional identity score was observed in the clinical laboratory science students. However, the effect size (r) was moderate. [Conclusion] Although professional identity formation fluctuates immediately after the experience of the hands-on experience of a cadaver dissection, the findings do suggest that these hands-on sessions will be effective for developing their professional identity if educational support is provided to help them utilize what they learned through reflection.

Published
2019

23. Microtropins Q–W, ent-Labdane Glucosides: Microtropiosides G–I, Ursane-Type Triterpene Diglucoside and Flavonol Glycoside from the Leaves of Microtropis japonica

Author

Terazawa, Saori, primary, Uemura, Yuka, additional, Koyama, Yuka, additional, Kawakami, Susumu, additional, Sugimoto, Sachiko, additional, Matsunami, Katsuyoshi, additional, Otsuka, Hideaki, additional, Shinzato, Takakazu, additional, Kawahata, Masatoshi, additional, and Yamaguchi, Kentaro, additional

Published
2017
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28. Doping-induced ferroelectric phase transition in strontium titanate: Observation of birefringence and coherent phonons under ultraviolet illumination

Author

Koyama, Yuka, Moriyasu, Takeshi, Okamura, E., オカムラ, E., Yamada, Y., ヤマダ, Y., Tanaka, Koichiro, and Kohmoto, Toshiro

Subjects
Phase transition, Birefringence, Materials science, Condensed matter physics, business.industry, Phonon, Soft modes, Condensed Matter Physics, Polarization (waves), Ferroelectricity, Electronic, Optical and Magnetic Materials, Condensed Matter::Materials Science, chemistry.chemical_compound, chemistry, Condensed Matter::Superconductivity, Strontium titanate, Optoelectronics, Condensed Matter::Strongly Correlated Electrons, business, Spectroscopy
Abstract

The doping-induced ferroelectric phase transition in Ca-doped ${\text{SrTiO}}_{3}$ is investigated by observing the birefringence and coherent phonons. The structural phase-transition temperature is determined by the birefringence measurement. Coherent phonons of the soft modes are studied by using ultrafast polarization spectroscopy. Two phonon modes are observed to be softened toward the ferroelectric phase-transition point at 28 K and other two phonon modes are observed to be softened toward the structural phase-transition point at 180 K. Another structural deformation at 25 K is found below the ferroelectric phase-transition temperature. From the temperature dependence of phonon frequencies under an ultraviolet (UV) illumination, a shift of the ferroelectric phase-transition point toward the lower temperature side is found. A decrease in phonon frequencies after the UV illumination is also found.

Published
2010

29. Photoinduced Dynamics in Pure and Ca-Doped SrTiO3 Studied by Transient Birefringence and Absorption Measurements

Author

Kohmoto, Toshiro, Koyama, Yuka, Moriyasu, Takeshi, Okamura, Hidekazu, Yamada, Yasuhiro, and Tanaka, Koichiro

Abstract

The photoinduced dynamics of the lattice deformation and the relaxed excited state in SrTiO3is studied by stationary- and transient-birefringence and pump--probe measurements in comparison with the doping-induced ferroelectric lattice deformation in Ca-doped SrTiO3. Ca-doped SrTiO3is found to exhibit first-order-like structural deformation with a small threshold UV intensity (${\sim}10^{-3}$ mW/mm2), and it is also found to exhibit a shift in the ferroelectric transition temperature under UV illumination. The photoinduced lattice deformation has the same order of magnitude as the ferroelectric lattice deformation, and it is not affected by the electric field. The occupation probability in the relaxed excited state is found to increase significantly at low temperatures. These experimental results suggest that the photoinduced giant dielectric response of SrTiO3is consistent with the conductive-region model rather than the ferroelectric cluster model. SrTiO3is a peculiar material in which dielectricity of the Maxwell--Wagner type appears in a stoichiometric material only under UV illumination.

Published
2011
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