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224 results on '"Norikane, Yasuo"'

1. Dynamic manipulation of friction in smart textile composites of liquid-crystal elastomers

Author

Ohzono, Takuya, Saed, Mohand O., Yue, Youfeng, Norikane, Yasuo, and Terentjev, Eugene M.

Subjects
Physics - Applied Physics, Condensed Matter - Materials Science, Condensed Matter - Soft Condensed Matter
Abstract

Smart surfaces that reversibly change the interfacial friction coefficients in response to external stimuli enable a wide range of applications, such as grips, seals, brake pads, packaging films, and fabrics. Here a new concept of such a smart frictional system is reported: a composite film of a plain-weave polyester textile sheet, and a thermo-responsive nematic liquid crystalline elastomer (LCE). The composite is deployed with retractable micro-undulations of the elastomer inside each weave mesh, enabling dramatic changes of the contact interface with the opposing surface on LCE actuation, which is induced e.g. by a change in temperature (T). At ambient T, the protruding viscoelastic parts of LCE in the nematic phase make contact with the opposing flat surface, resulting in a very high friction. At an elevated T (50C, isotropic phase), the undulations of LCE surface are retracted within the thickness of the textile, and the contacts are limited to small regions around overlapping textile fibers, lowering the friction dramatically. This effect is fully reversible on heating/cooling cycles. The surface undulations are spontaneous, i.e. fabricated without any lithographic or alignment techniques. The present composite opens a new way to practical uses of sheets/films with switchable friction enabled by stimuli-responsive LCEs.

Published
2019
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9. Visualization of the Dynamics of Photoinduced Crawling Motion of 4-(Methylamino)Azobenzene Crystals via Diffracted X-ray Tracking

Author

Saito, Koichiro, primary, Ichiyanagi, Kouhei, additional, Fukaya, Ryo, additional, Haruki, Rie, additional, Nozawa, Shunsuke, additional, Sasaki, Daisuke, additional, Arai, Tatsuya, additional, Sasaki, Yuji C., additional, McGehee, Keegan, additional, Saikawa, Makoto, additional, Gao, Minghao, additional, Wei, Zhichao, additional, Kwaria, Dennis, additional, and Norikane, Yasuo, additional

Published
2023
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13. Releasing a bound molecular spring with light: a visible light-triggered photosalient effect tied to polymorphism.

Author

McGehee, Keegan, Saito, Koichiro, Kwaria, Dennis, Minamikawa, Hiroyuki, and Norikane, Yasuo

Abstract

Here we present a study on the solid state properties of trans tetra-ortho-bromo azobenzene (4Br-Azo). Two distinct crystal polymorphs were identified: the α-phase and β-phase. Notably, only the β-phase exhibited an extraordinary photosalient effect (jumping/breaking) upon exposure to a wide range of visible light. Powder X-ray diffraction and Raman spectroscopy revealed that the β-phase is metastable and can transition to the α-phase when subjected to specific stimuli like heat and light. Furthermore, single crystal X-ray diffraction and density functional theory calculations highlighted the significance of a highly strained conformer in the β-phase, showing that the metastability of the phase potentially arises from relieving this strain. This metastability leads to a light induced phase transition, which appears to be the cause of the photosalient effect in these crystals. Interestingly the polymorphism at the core of 4Br-Azo's dynamic behavior is based on different arrangements of halogen based intermolecular interactions. It is possible that continued study on combining visible light capturing chromophores with halogen interaction-based polymorphism will lead to the discovery of even more visible light controlled dynamic crystal materials. [ABSTRACT FROM AUTHOR]

Published
2024
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28. Optical Control of Aggregation‐Induced Emission Shift by Photoisomerizable Precipitant in a Liquid Droplet Microresonator.

Author

Zhao, Shuai, Yamagishi, Hiroshi, Norikane, Yasuo, Hayashi, Shotaro, and Yamamoto, Yohei

Subjects
OPTICAL control, INTRAMOLECULAR charge transfer, EMISSION control, OPTICAL properties, MOLECULAR structure, IRRADIATION, DIARYLETHENE, INTRAMOLECULAR proton transfer reactions, SPIRO compounds
Abstract

Emission‐switchable fluorophores often include stimuli‐responsive units in their molecular structures. This strategy works well, but the applicable compounds are limited to the derivatives of several kinds of photochromic molecules such as diarylethene, azobenzene, and spiropyran. Here, this work presents a simple methodology based on a photoresponsive precipitant for achieving color‐switchable photoluminescence. A luminescent dye, cyano‐substituted oligo(phenylenevinylene) (COPV), features both twisted intramolecular charge transfer and aggregation‐induced emission shift properties, leading to the change in the luminescence color from green to red upon precipitation. The COPV, together with photoisomerizable precipitant azobenzene (C6), is doped into spherical droplets of epoxy resin (ER) in a liquid state. The photoisomerization of C6 induced by UV irradiation and heating alternatively precipitates out and dissolves COPV in ER and changes the photoluminescence color, while maintaining the optical microresonator properties. This study will open a promising way for assembling/disassembling novel emission color‐switchable systems. [ABSTRACT FROM AUTHOR]

Published
2023
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39. Photoinduced hinge-like molecular motion: studies on xanthene-based cyclic azobenzene dimers

Author

Nagamani, S. Anitha, Norikane, Yasuo, and Tamaoki, Nobuyuki

Subjects
Azo compounds -- Atomic properties, Azo compounds -- Chemical properties, Benzene -- Atomic properties, Benzene -- Chemical properties, Biological sciences, Chemistry
Abstract

The synthesis, X-ray crystal analysis, photochemical and thermal studies of a xanthene based cyclic azobenzene dimer and its precursor is described. The X-ray crystal structures of the trans-trans isomer (open) and the cis-cis isomer (closed) provide unambiguous proof for the hinge-like molecular motion in the class of molecules.

Published
2005

47. High Efficiency Microwave Flow Chemistry Towards Synthesis of Functional Materials and Pharmaceutical Cores

Author

New Energy and Industrial Technology Development Organization, Japón, Japan Society for the Promotion of Science, Barham, Joshua, Koyama, Emiko, Sugiyama, Jun-ichi, Norikane, Yasuo, Egami, Hiromichi, Hamashima, Yoshitaka, New Energy and Industrial Technology Development Organization, Japón, Japan Society for the Promotion of Science, Barham, Joshua, Koyama, Emiko, Sugiyama, Jun-ichi, Norikane, Yasuo, Egami, Hiromichi, and Hamashima, Yoshitaka

Abstract

[EN] Microwave (MW) heating benefits organic synthesis by affording higher product yields in shorter time periods than conventional heating, yet it suffers from poor scalability and is limited to polar solvents in typical batch mode reactors. Herein, we report a microwave flow reactor using a solid-state semiconductor MW generator. The tunable, single-mode MW heating allows high efficiency, scalable organic synthesis, rapid reaction optimization and is applicable to non-polar solvents (o-Xylene and CPME can be rapidly heated to ca. 260 oC). Auto-frequency tuning compensates for changes in the microwave absorption properties (permittivity, epsilon) with increasing temperature, affording excellent temperature and process control. This technology unlocked unprecedented g/h productivity of C60/fullerene-indene monoadduct (IC60MA) and facilitated a novel, transition metal-free amide-styrene coupling reaction for synthesis of amide-containing pharmaceutical cores in up to 65 g/h (Figure 1). An ortho-Claisen rearrangement reaction was rapidly optimised.

Published
2019

48. High Efficiency Microwave Flow Chemistry Towards Synthesis of Functional Materials and Pharmaceutical Cores

Author

New Energy and Industrial Technology Development Organization, Japan Society for the Promotion of Science, Barham, Joshua, Koyama, Emiko, Sugiyama, Jun-ichi, Norikane, Yasuo, Egami, Hiromichi, Hamashima, Yoshitaka, New Energy and Industrial Technology Development Organization, Japan Society for the Promotion of Science, Barham, Joshua, Koyama, Emiko, Sugiyama, Jun-ichi, Norikane, Yasuo, Egami, Hiromichi, and Hamashima, Yoshitaka

Abstract

[EN] Microwave (MW) heating benefits organic synthesis by affording higher product yields in shorter time periods than conventional heating, yet it suffers from poor scalability and is limited to polar solvents in typical batch mode reactors. Herein, we report a microwave flow reactor using a solid-state semiconductor MW generator. The tunable, single-mode MW heating allows high efficiency, scalable organic synthesis, rapid reaction optimization and is applicable to non-polar solvents (o-Xylene and CPME can be rapidly heated to ca. 260 oC). Auto-frequency tuning compensates for changes in the microwave absorption properties (permittivity, epsilon) with increasing temperature, affording excellent temperature and process control. This technology unlocked unprecedented g/h productivity of C60/fullerene-indene monoadduct (IC60MA) and facilitated a novel, transition metal-free amide-styrene coupling reaction for synthesis of amide-containing pharmaceutical cores in up to 65 g/h (Figure 1). An ortho-Claisen rearrangement reaction was rapidly optimised.

Published
2019

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