Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Mitsuhiro Murayama Last modified date:2021.08.02

Professor / Department of Integrated Materials / Institute for Materials Chemistry and Engineering


Papers
1. M.F. Hochella, D.W Mogk, J. Ranville, I.C Allen, G.W. Luther, L.C. Marr, B. Peter McGrail, Mitsu Murayama, Nikolla P Qafoku, Kevin M Rosso, Nita Sahai, P.A. Schroeder, Peter Vikesland, Paul Westerhoff, Yi Yang, Natural, incidental, and engineered nanomaterials and their impacts on the Earth system, Science, 10.1126/science.aau8299, 363, 6434, eaau8299, 2019.03.
2. Toshiki Shimizu, Dominik Lungerich, Joshua Stuckner, Mitsuhiro Murayama, Koji Harano, Eiichi Nakamura, Real-time Video Imaging of Mechanical Motions of a Single Molecular Shuttle, ChemRxiv, 2019.10, [URL].
3. SHIMIZU, T., LUNGERICH, D., STUCKNER, J., MURAYAMA, M., HARANO, K. & NAKAMURA, E., Real-time Video Imaging of Mechanical Motions of a Single Molecular Shuttle with Sub-millisecond Sub-angstrom Precision, Bulletin of the Chemical Society of Japan , 10.1246/bcsj.20200134, 2020.05.
4. Toshiki Shimizu, Dominik Lungerich, Joshua Stuckner, Mitsuhiro Murayama, Koji Harano, Eiichi Nakamura, Real-Time Video Imaging of Mechanical Motions of a Single Molecular Shuttle with Sub-Millisecond Sub-Angstrom Precision, Bulletin of the Chemical Society of Japan , https://doi.org/10.1246/bcsj.20200134, 93, 9, 1079-1085, 2020.06, Miniaturized machines have open up a new dimension of chemistry, studied usually as an average over numerous molecules or for a single molecule bound on a robust substrate. Mechanical motions at a single molecule level, however, are under quantum control, strongly coupled with fluctuations of its environment — a system rarely addressed because an efficient way of observing the nanomechanical motions in real time is lacking. Here, we report sub-millisecond sub-Å precision in situ video imaging of a single fullerene molecule shuttling, rotating, and interacting with a vibrating carbon nanotube at 0.625 milliseconds(ms)/frame or 1600 fps, using an electron microscope, a fast camera, and a denoising algorithm. We have achieved in situ observation of the mechanical motions of a molecule coupled with vibration of a carbon nanotube with standard error as small as 0.9 millisecond in time and 0.01 nm in space. We have revealed rich molecular dynamics, where motions are non-linear, stochastic and often non-repeatable, and a work and energy relationship at a molecular level previously undetected by time-averaged measurements or microscopy. The molecular video recording at a 1600-fps rate exceeds by 100 times the previous records of continuous recording of molecular motions..
5. Joshua Stuckner, Toshiki Shimizu, Koji Harano, Eiichi Nakamura, Mitsuhiro Murayama, Ultra-Fast Electron Microscopic Imaging of Single Molecules With a Direct Electron Detection Camera and Noise Reduction, Microscopy and Microanalysis, https://doi.org/10.1017/S1431927620001750[Opens in a new window], 26, 4, 667-675, 2020.07, Time-resolved imaging of molecules and materials made of light elements is an emerging field of transmission electron microscopy (TEM), and the recent development of direct electron detection cameras, capable of taking as many as 1,600 fps, has potentially broadened the scope of the time-resolved TEM imaging in chemistry and nanotechnology. However, such a high frame rate reduces electron dose per frame, lowers the signal-to-noise ratio (SNR), and renders the molecular images practically invisible. Here, we examined image noise reduction to take the best advantage of fast cameras and concluded that the Chambolle total variation denoising algorithm is the method of choice, as illustrated for imaging of a molecule in the 1D hollow space of a carbon nanotube with ~1 ms time resolution. Through the systematic comparison of the performance of multiple denoising algorithms, we found that the Chambolle algorithm improves the SNR by more than an order of magnitude when applied to TEM images taken at a low electron dose as required for imaging at around 1,000 fps..
6. CY Hung, Y Bai, T Shimokawa, N Tsuji, M Murayama, A correlation between grain boundary character and deformation twin nucleation mechanism in coarse-grained high-Mn austenitic steel., Scientific reports, https://doi.org/10.1038/s41598-021-87811-w, 11, 8468, 2021.04.
7. CY Hung, Y Bai, N Tsuji, M Murayama, Grain size altering yielding mechanisms in ultrafine grained high-Mn austenitic steel: advanced TEM investigations, Journal of Materials Science & Technology, https://doi.org/10.1016/j.jmst.2021.01.031, 86, 192-203, 2021.09.