The Experts below are selected from a list of 98520 Experts worldwide ranked by ideXlab platform
Dirk Bouwmeester - One of the best experts on this subject based on the ideXlab platform.
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ideal relaxation of the hopf fibration
Physics of Plasmas, 2017Co-Authors: C B Smiet, Simon Candelaresi, Dirk BouwmeesterAbstract:Ideal magnetohydrodynamics relaxation is the topology-conserving reconfiguration of a magnetic field into a Lower Energy State where the net force is zero. This is achieved by modeling the plasma as perfectly conducting viscous fluid. It is an important tool for investigating plasma equilibria and is often used to study the magnetic configurations in fusion devices and astrophysical plasmas. We study the equilibrium reached by a localized magnetic field through the topology conserving relaxation of a magnetic field based on the Hopf fibration in which magnetic field lines are closed circles that are all linked with one another. Magnetic fields with this topology have recently been shown to occur in non-ideal numerical simulations. Our results show that any localized field can only attain equilibrium if there is a finite external pressure, and that for such a field a Taylor State is unattainable. We find an equilibrium plasma configuration that is characterized by a Lowered pressure in a toroidal region, w...
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ideal relaxation of the hopf fibration
arXiv: Plasma Physics, 2016Co-Authors: C B Smiet, Simon Candelaresi, Dirk BouwmeesterAbstract:Ideal MHD relaxation is the topology-conserving reconfiguration of a magnetic field into a Lower Energy State where the net force is zero. This is achieved by modeling the plasma as perfectly conducting viscous fluid. It is an important tool for investigating plasma equilibria and is often used to study the magnetic configurations in fusion devices and astrophysical plasmas. We study the equilibrium reached by a localized magnetic field through the topology conserving relaxation of a magnetic field based on the Hopf fibration in which magnetic field lines are closed circles that are all linked with one another. Magnetic fields with this topology have recently been shown to occur in non-ideal numerical simulations. Our results show that any localized field can only attain equilibrium if there is a finite external pressure, and that for such a field a Taylor State is unattainable. We find an equilibrium plasma configuration that is characterized by a Lowered pressure in a toroidal region, with field lines lying on surfaces of constant pressure. Therefore, the field is in a Grad-Shafranov equilibrium. Localized helical magnetic fields are found when plasma is ejected from astrophysical bodies and subsequently relaxes against the background plasma, as well as on earth in plasmoids generated by e.g.\ a Marshall gun. This work shows under which conditions an equilibrium can be reached and identifies a toroidal depression as the characteristic feature of such a configuration.
Keiji Tanaka - One of the best experts on this subject based on the ideXlab platform.
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conformational relaxation of poly styrene co butadiene chains at substrate interface in spin coated and solvent cast films
Macromolecules, 2018Co-Authors: Biao Zuo, Manabu Inutsuka, Daisuke Kawaguchi, Xinping Wang, Keiji TanakaAbstract:The local conformation of poly(styrene-co-butadiene) rubber (SBR) chains in direct contact with a quartz substrate was examined by interface-sensitive sum-frequency generation (SFG) spectroscopy. SFG signals, which could be obtained from functional groups only oriented at the interface, were clearly observed for SBR in a film at room temperature which was much higher than the bulk glass transition temperature (Tg). When the film was thermally annealed, SBR chains at the quartz interface changed their conformation to one with a Lower Energy State, accompanied by the randomization of both the main and side chain parts. The characteristic temperature, at which interfacial chains started to lose their orientations, was much higher than the bulk Tg. Also, the extent found to be more remarkable for the spin-coated film than for the solvent-cast one. This implies that the stress accumulated at the interface, which resulted from the centrifugal force during the spin-coating process, accelerates the mobility of ch...
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Conformational Relaxation of Poly(styrene-co-butadiene) Chains at Substrate Interface in Spin-Coated and Solvent-Cast Films
2018Co-Authors: Biao Zuo, Manabu Inutsuka, Daisuke Kawaguchi, Xinping Wang, Keiji TanakaAbstract:The local conformation of poly(styrene-co-butadiene) rubber (SBR) chains in direct contact with a quartz substrate was examined by interface-sensitive sum-frequency generation (SFG) spectroscopy. SFG signals, which could be obtained from functional groups only oriented at the interface, were clearly observed for SBR in a film at room temperature which was much higher than the bulk glass transition temperature (Tg). When the film was thermally annealed, SBR chains at the quartz interface changed their conformation to one with a Lower Energy State, accompanied by the randomization of both the main and side chain parts. The characteristic temperature, at which interfacial chains started to lose their orientations, was much higher than the bulk Tg. Also, the extent found to be more remarkable for the spin-coated film than for the solvent-cast one. This implies that the stress accumulated at the interface, which resulted from the centrifugal force during the spin-coating process, accelerates the mobility of chains there. Finally, the kinetics experiment well supports the sLower orientation relaxation at the interface
Biao Zuo - One of the best experts on this subject based on the ideXlab platform.
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conformational relaxation of poly styrene co butadiene chains at substrate interface in spin coated and solvent cast films
Macromolecules, 2018Co-Authors: Biao Zuo, Manabu Inutsuka, Daisuke Kawaguchi, Xinping Wang, Keiji TanakaAbstract:The local conformation of poly(styrene-co-butadiene) rubber (SBR) chains in direct contact with a quartz substrate was examined by interface-sensitive sum-frequency generation (SFG) spectroscopy. SFG signals, which could be obtained from functional groups only oriented at the interface, were clearly observed for SBR in a film at room temperature which was much higher than the bulk glass transition temperature (Tg). When the film was thermally annealed, SBR chains at the quartz interface changed their conformation to one with a Lower Energy State, accompanied by the randomization of both the main and side chain parts. The characteristic temperature, at which interfacial chains started to lose their orientations, was much higher than the bulk Tg. Also, the extent found to be more remarkable for the spin-coated film than for the solvent-cast one. This implies that the stress accumulated at the interface, which resulted from the centrifugal force during the spin-coating process, accelerates the mobility of ch...
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Conformational Relaxation of Poly(styrene-co-butadiene) Chains at Substrate Interface in Spin-Coated and Solvent-Cast Films
2018Co-Authors: Biao Zuo, Manabu Inutsuka, Daisuke Kawaguchi, Xinping Wang, Keiji TanakaAbstract:The local conformation of poly(styrene-co-butadiene) rubber (SBR) chains in direct contact with a quartz substrate was examined by interface-sensitive sum-frequency generation (SFG) spectroscopy. SFG signals, which could be obtained from functional groups only oriented at the interface, were clearly observed for SBR in a film at room temperature which was much higher than the bulk glass transition temperature (Tg). When the film was thermally annealed, SBR chains at the quartz interface changed their conformation to one with a Lower Energy State, accompanied by the randomization of both the main and side chain parts. The characteristic temperature, at which interfacial chains started to lose their orientations, was much higher than the bulk Tg. Also, the extent found to be more remarkable for the spin-coated film than for the solvent-cast one. This implies that the stress accumulated at the interface, which resulted from the centrifugal force during the spin-coating process, accelerates the mobility of chains there. Finally, the kinetics experiment well supports the sLower orientation relaxation at the interface
Manabu Inutsuka - One of the best experts on this subject based on the ideXlab platform.
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conformational relaxation of poly styrene co butadiene chains at substrate interface in spin coated and solvent cast films
Macromolecules, 2018Co-Authors: Biao Zuo, Manabu Inutsuka, Daisuke Kawaguchi, Xinping Wang, Keiji TanakaAbstract:The local conformation of poly(styrene-co-butadiene) rubber (SBR) chains in direct contact with a quartz substrate was examined by interface-sensitive sum-frequency generation (SFG) spectroscopy. SFG signals, which could be obtained from functional groups only oriented at the interface, were clearly observed for SBR in a film at room temperature which was much higher than the bulk glass transition temperature (Tg). When the film was thermally annealed, SBR chains at the quartz interface changed their conformation to one with a Lower Energy State, accompanied by the randomization of both the main and side chain parts. The characteristic temperature, at which interfacial chains started to lose their orientations, was much higher than the bulk Tg. Also, the extent found to be more remarkable for the spin-coated film than for the solvent-cast one. This implies that the stress accumulated at the interface, which resulted from the centrifugal force during the spin-coating process, accelerates the mobility of ch...
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Conformational Relaxation of Poly(styrene-co-butadiene) Chains at Substrate Interface in Spin-Coated and Solvent-Cast Films
2018Co-Authors: Biao Zuo, Manabu Inutsuka, Daisuke Kawaguchi, Xinping Wang, Keiji TanakaAbstract:The local conformation of poly(styrene-co-butadiene) rubber (SBR) chains in direct contact with a quartz substrate was examined by interface-sensitive sum-frequency generation (SFG) spectroscopy. SFG signals, which could be obtained from functional groups only oriented at the interface, were clearly observed for SBR in a film at room temperature which was much higher than the bulk glass transition temperature (Tg). When the film was thermally annealed, SBR chains at the quartz interface changed their conformation to one with a Lower Energy State, accompanied by the randomization of both the main and side chain parts. The characteristic temperature, at which interfacial chains started to lose their orientations, was much higher than the bulk Tg. Also, the extent found to be more remarkable for the spin-coated film than for the solvent-cast one. This implies that the stress accumulated at the interface, which resulted from the centrifugal force during the spin-coating process, accelerates the mobility of chains there. Finally, the kinetics experiment well supports the sLower orientation relaxation at the interface
Daisuke Kawaguchi - One of the best experts on this subject based on the ideXlab platform.
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conformational relaxation of poly styrene co butadiene chains at substrate interface in spin coated and solvent cast films
Macromolecules, 2018Co-Authors: Biao Zuo, Manabu Inutsuka, Daisuke Kawaguchi, Xinping Wang, Keiji TanakaAbstract:The local conformation of poly(styrene-co-butadiene) rubber (SBR) chains in direct contact with a quartz substrate was examined by interface-sensitive sum-frequency generation (SFG) spectroscopy. SFG signals, which could be obtained from functional groups only oriented at the interface, were clearly observed for SBR in a film at room temperature which was much higher than the bulk glass transition temperature (Tg). When the film was thermally annealed, SBR chains at the quartz interface changed their conformation to one with a Lower Energy State, accompanied by the randomization of both the main and side chain parts. The characteristic temperature, at which interfacial chains started to lose their orientations, was much higher than the bulk Tg. Also, the extent found to be more remarkable for the spin-coated film than for the solvent-cast one. This implies that the stress accumulated at the interface, which resulted from the centrifugal force during the spin-coating process, accelerates the mobility of ch...
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Conformational Relaxation of Poly(styrene-co-butadiene) Chains at Substrate Interface in Spin-Coated and Solvent-Cast Films
2018Co-Authors: Biao Zuo, Manabu Inutsuka, Daisuke Kawaguchi, Xinping Wang, Keiji TanakaAbstract:The local conformation of poly(styrene-co-butadiene) rubber (SBR) chains in direct contact with a quartz substrate was examined by interface-sensitive sum-frequency generation (SFG) spectroscopy. SFG signals, which could be obtained from functional groups only oriented at the interface, were clearly observed for SBR in a film at room temperature which was much higher than the bulk glass transition temperature (Tg). When the film was thermally annealed, SBR chains at the quartz interface changed their conformation to one with a Lower Energy State, accompanied by the randomization of both the main and side chain parts. The characteristic temperature, at which interfacial chains started to lose their orientations, was much higher than the bulk Tg. Also, the extent found to be more remarkable for the spin-coated film than for the solvent-cast one. This implies that the stress accumulated at the interface, which resulted from the centrifugal force during the spin-coating process, accelerates the mobility of chains there. Finally, the kinetics experiment well supports the sLower orientation relaxation at the interface
