Yuki Yamamoto

University of Yamanashi

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Akiya Ogawa

Osaka Metropolitan University

Akihiro Nomoto

Osaka Prefecture University

Shintaro Kodama

Osaka Prefecture University

Kuniharu Takei

Hokkaido University

Takayuki Arie

Osaka Metropolitan University

Seiji Akita

Osaka Metropolitan University

Shinichi Kawaguchi

Saga University

Kenichiro Kanao

Osaka Prefecture University

Shingo Harada

Mazda Motor Corporation (Japan)

Heiji YASUI

Kumamoto University

Cooperative Institutions

Osaka Prefecture University

The University of Tokyo

Kyoto University

Osaka Metropolitan University

Osaka University

National Institute of Advanced Industrial Science and Technology

Osaka City University

Japan Science and Technology Agency

Kyushu University

Tohoku University

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Analysis of Ion-Irradiation Induced Lattice Expansion and Ferromagnetic State in CeO2 by Using Poisson Distribution Function

Quantum Beam Science (2020)

Yuki Yamamoto N. Ishikawa Fuminobu Hori A. Iwase

The lattice constant and the magnetic state of CeO2 are modified by the irradiation with 200 MeV Xe ions. Under the assumption that these modifications are induced in the narrow one-dimensional region (the ion track) along the ion beam path, the dependence of the lattice constant and the saturation magnetization of CeO2 on the Xe ion fluence was analyzed by using the Poisson distribution function. The analysis reveals that the lattice constant inside the ion track, which is larger than that outside the ion track, is not affected by the overlapping of the ion track. On the other hand, the ferromagnetic state is induced inside the ion track, but the analysis shows that this ferromagnetic state is gradually destroyed due to the overlapping of the ion track. The present result implies that the Poisson distribution function is useful for describing the effect of the ion track overlapping on the ion irradiation-induced ferromagnetic state in CeO2.

Lattice constant

Lattice (music)

10.3390/qubs4030026

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Citations (8)

Phosphorus-Recycling Wittig Reaction: Design and Facile Synthesis of a Fluorous Phosphine and Its Reusable Process in the Wittig Reaction

The Journal of Organic Chemistry (2020)

Yuki Yamamoto Shinichi Kawaguchi Misaki Nishimura Yuki Sato Yoshihisa Shimada

This study shows that phosphorus sources can be recycled using the appropriate fluorous phosphine in the Wittig reaction. The designed fluorous phosphine, which has an ethylene spacer between its phosphorus atom and the perfluoroalkyl group, was synthesized from air-stable phosphine reagents. The synthesized phosphine can be used for the Wittig reaction process to obtain various alkenes in adequate yields and stereoselectivity. The concomitantly formed fluorous phosphine oxide was extracted from the reaction mixture using a fluorous biphasic system. The fluorous phosphine was regenerated by reducing the fluorous phosphine oxide with diisobutylaluminum hydride. Finally, a series of gram scale phosphorus recycling processes were performed, which included the Wittig reaction, separation, reduction, and reuse.

Wittig reaction

Phosphine oxide

Deoxygenation

10.1021/acs.joc.0c01926

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Citations (12)

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

Beilstein Journal of Organic Chemistry (2024)

Akiya Ogawa Yuki Yamamoto

Isocyanide is a promising synthetic reagent not only as a one-carbon homologation reagent but also as a nitrogen source for nitrogen-containing molecules. Because of their isoelectronic structure with carbon monoxide, isocyanides also react with nucleophiles, electrophiles, carbon radicals, and transition metal reagents, and are widely used in organic synthesis. On the other hand, the use of isocyanides in reactions with heteroatom radicals is limited. However, the reaction of isocyanides with heteroatom radicals is a promising synthetic tool for the construction of nitrogen-containing organic molecules modified with a variety of heteroatoms. In this Perspective, we review the addition and cyclization reactions of heteroatom radicals with isocyanides and discuss the synthetic prospects of the reaction of isocyanides with heteroatom radicals.

Heteroatom

Organic Synthesis

10.3762/bjoc.20.182

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Mesh Moving Method for Improvement of Robustness of FSI analysis

Keisan Rikigaku Koenkai koen ronbunshu/Keisan Rikigaku Kouenkai kouen rombunshuu (2016)

Yuki Yamamoto Giwon Hong Tomonori Yamada Shinobu Yoshimura

Robustness

10.1299/jsmecmd.2016.29.4_192

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GS15 Tensile Properties and Effect for dispersed finely cementite of QT steel using Super Rapid Induction Tempering

The Proceedings of the Materials and Mechanics Conference (2012)

Ryosuke MIYAKODA Yuki Yamamoto Tadao FUKUTA Kiyotaka Obunai Koichi OZAKI

The purpose of this study is to investigate the tensile properties of super rapid tempering steel treated by high frequency induction heating method. In order to discuss the effect of tempering time on tensile properties, two types of specimens in which tempering time was different were prepared. Super rapid tempering specimen (IHT steel) was tempered for 0.35 sec by induction heating, and conventional tempering specimen (FT steel) was tempered for 3.6 Ksec by furnace tempering. While both of specimens were quenched by induction heating .These specimens were evaluated at room temperature. As a result, the both steel had almost same tensile strength. However the true stress of fracture of IHT steel was higher than that of FT steel. This result was explained by the reduction of area of IHT steel was higher than that of FT steel. The toughness of both specimens was also evaluated by the measuring area of nominal stress-nominal strain diagram. The toughness of IHT steel was 30% higher than that of FT steel. SEM observation suggested that the cementite particle of IHT steel was smaller and more finely dispersed compared to FT steel.

Tempering

Induction Heating

10.1299/jsmemm.2012._gs15-1_

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Ammonium and nitrate contamination source and dynamics in groundwater of Kathmandu Valley, Nepal

Japan Geoscience Union (2016)

Takashi Nakamura Kei Nishida Suresh Das Shrestha Yuki Yamamoto Kazuki Akahane

Groundwater Contamination

Ammonium nitrate

Source

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Transition-metal-free synthesis of arylboronates via thermal generation of aryl radicals from triarylbismuthines in air

Beilstein Journal of Organic Chemistry (2024)

Yuki Yamamoto Yuki Konakazawa Kohsuke Fujiwara Akiya Ogawa

A simple and versatile synthesis of arylboronates has been achieved by using triarylbismuthines as aryl radical sources under transition-metal-free and open-air conditions. Conventional methods required photoirradiation or electrolysis to generate aryl radicals from triarylbismuthines. In this study, it was found that simply heating the solution of triarylbismuthines in benzotrifluoride (BTF) in air successfully led to the generation of aryl radicals, and the subsequent reaction with bis(pinacolato)diboron afforded a variety of arylboronates in moderate to good yields.

Open air

10.3762/bjoc.20.216

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Fully Printed Flexible Fingerprint-like Three-Axis Tactile and Slip Force and Temperature Sensors for Artificial Skin

ACS Nano (2014)

Shingo Harada Kenichiro Kanao Yuki Yamamoto Takayuki Arie Seiji Akita

A three-axis tactile force sensor that determines the touch and slip/friction force may advance artificial skin and robotic applications by fully imitating human skin. The ability to detect slip/friction and tactile forces simultaneously allows unknown objects to be held in robotic applications. However, the functionalities of flexible devices have been limited to a tactile force in one direction due to difficulties fabricating devices on flexible substrates. Here we demonstrate a fully printed fingerprint-like three-axis tactile force and temperature sensor for artificial skin applications. To achieve economic macroscale devices, these sensors are fabricated and integrated using only printing methods. Strain engineering enables the strain distribution to be detected upon applying a slip/friction force. By reading the strain difference at four integrated force sensors for a pixel, both the tactile and slip/friction forces can be analyzed simultaneously. As a proof of concept, the high sensitivity and selectivity for both force and temperature are demonstrated using a 3 × 3 array artificial skin that senses tactile, slip/friction, and temperature. Multifunctional sensing components for a flexible device are important advances for both practical applications and basic research in flexible electronics.

Tactile sensor

Normal force

Contact force

Artificial skin

10.1021/nn506293y

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Citations (317)

Transition‐Metal‐Catalyzed Addition of Organosulfur Compounds to Alkynes and Alkenes: Catalysis and Catalyst Poisons

Chemistry - A European Journal (2023)

Yuki Yamamoto Akiya Ogawa

The addition of heteroatom compounds to alkynes and alkenes is an atom-efficient method of carbon-heteroatom bond formation and is widely used as a fundamental synthetic method for the construction of functional molecules. Nevertheless, examples of transition-metal-catalyzed addition reactions of group 16 heteroatom compounds to carbon-carbon unsaturated bonds have been limited due to the widespread belief that organic sulfur and selenium compounds are representative catalyst poisons. In recent decades, however, several seminal catalytic reactions of sulfur compounds have been developed, providing important insights into catalysis and poisons. Therefore, this paper focuses on the transition-metal-catalyzed addition of organosulfur compounds to alkynes and alkenes, gains comprehensive insights into the catalysis and catalyst poisons, and proposes concepts for the development of transition-metal-catalyzed reactions of group 16 heteroatom compounds.

Organosulfur compounds

10.1002/chem.202302432

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Citations (4)

Sport support system using realtime audio feedback

Yuki Yamamoto Daisuke Takafuji Yasuaki Ito Koji Nakano Tomoko Kashima

In recent years, a smart phone which has highly efficient processor and a large number of sensors is gaining popularity. Since the smart phone is so small, it is convenient to carry, and many sport supporting systems have been developed using smartphone sensors. However, they are so simple that for example, a running support system calculates mileage, pace and records a route, and a pedometer records the number of steps. In this research, we propose sport support system using an Apple iPhone which analyzes movement data from accelerator, and gives with real time audio feedback.

Pace

Pedometer

Popularity

Carry (investment)

Mobile phone

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