Yohei Yamamoto
University of Tsukuba
Publications 105
#1T. MoriH-Index: 19
Last.Seiji KojimaH-Index: 29
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Disordered systems exhibit universal excitation, referred to as the boson peak, in the terahertz region. Meanwhile, the so-called fracton is expected to appear in the nanoscale region owing to the self-similar structure of monomers in polymeric glasses. We demonstrate that such excitations can be detected using terahertz spectroscopy. For the interaction between terahertz light and the vibrational density of states of the fractal structure, we formulate an infrared light-vibration coupling coeff...
#1Ken Albrecht (TITech: Tokyo Institute of Technology)H-Index: 11
#2Ken Minagawa (TITech: Tokyo Institute of Technology)
Last.Kimihisa Yamamoto (TITech: Tokyo Institute of Technology)H-Index: 28
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Formation of nanospheres that consist of π-conjugated dendrimers (phenylazomethine and carbazole) is reported. The nanospheres can be prepared by spin-casting a solution of dendrimers in a proper g...
#1Amandeep Jindal (University of Tsukuba)H-Index: 4
#2Kentaro Tashiro (National Institute for Materials Science)H-Index: 22
Last.Yohei Yamamoto (University of Tsukuba)H-Index: 22
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The development of highly efficient catalysts for electrochemical oxygen reduction reactions (ORRs) is crucial for energy applications such as metal–air batteries and fuel cells. Here, we show an enhanced electrocatalytic activity of a new functional material composed of Pt nanoparticles (PtNPs) and self-assembled β-sheet peptides (βPs). The PtNP/βP hybrids, under an optimized assembly condition, display an ORR electrocatalytic activity that is higher than that of a commercially available benchm...
#1T. Mori (University of Tsukuba)H-Index: 19
#2Leona Motoji (University of Tsukuba)
Last.Seiji Kojima (University of Tsukuba)H-Index: 29
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Terahertz time-domain spectroscopy has been applied to protein myoglobin dried sample. The boson peak (BP) which is a universal excitation of disordered system has been detected around 0.5 THz. While, fracton will be a universal excitation in the self-similar structure, and it has been observed above the BP frequency. How the fracton appear in the infrared spectrum is explained using the fracton model and the linear response theory for amorphous materials.
#1Yen-Jen Lin (NTHU: National Tsing Hua University)H-Index: 4
#2Hsin-Yu Chiang (NTHU: National Tsing Hua University)H-Index: 1
Last.Masaki Horie (NTHU: National Tsing Hua University)H-Index: 22
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A series of copolymers of poly(arylenevinylene)s have been prepared by ring-opening metathesis polymerization (ROMP) of cyclic conjugated monomers composed of cyclopentadithiophene, bis(thienyl)benzothiadiazole, or bithiophene using a second-generation Grubbs catalyst and the sequential monomer addition technique. The spectroscopic, electrochemical, and morphological properties of these polymers are tailored by changing the chemical structures and fractions of the monomers. The polymers self-ass...
#1Zakarias Seba Ngara (University of Tsukuba)H-Index: 1
#2Yohei Yamamoto (University of Tsukuba)H-Index: 22
We demonstrate a modulation of whispering gallery mode (WGM) photoluminescence (PL) from self-assembled microspheres of fluorene-terpyridine alternating copolymer by protonation/deprotonation. Upon...
#1Yohei YamamotoH-Index: 22
#1Zakarias Seba Ngara (University of Tsukuba)H-Index: 1
#2Daichi Okada (University of Tsukuba)H-Index: 5
Last.Yohei Yamamoto (University of Tsukuba)H-Index: 22
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