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Lu AKA, Lin J, Futamura Y, Sakurai T, Tamura R, Miyazaki T. Extraction of local structure differences in silica based on unsupervised learning. Phys Chem Chem Phys 2024; 26:11657-11666. [PMID: 38563149 DOI: 10.1039/d3cp06298h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Silica exhibits a rich phase diagram with numerous stable structures existing at different temperature and pressure conditions, including its glassy form. In large-scale atomistic simulations, due to the small energy difference, several phases may coexist. While, in terms of long-range order, there are clear differences between these phases, their short- or medium-range structural properties are similar for many phases, thus making it difficult to detect the structural differences. In this study, a methodology based on unsupervised learning is proposed to detect the differences in local structures between eight phases of silica, using atomic models prepared by molecular dynamics (MD) simulations. A combination of two-step locality preserving projections (TS-LPP) and locally averaged atomic fingerprints (LAAF) descriptor was employed to find a low-dimensional space in which the differences among all the phases can be detected. From the distance between each structure in the found low-dimensional space, the similarity between the structures can be discussed and subtle local changes in the structures can be detected. Using the obtained low-dimensional space, the β-α transition in quartz at a low temperature was analyzed, as well as the structural evolution during the melt-quench process starting from α-quartz. The proper differentiation and ease of visualization make the present methodology promising for improving the analysis of the structure and properties of glasses, where subtle differences in structure appear due to differences in the temperature and pressure conditions at which they were synthesized.
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Affiliation(s)
- Anh Khoa Augustin Lu
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-8568, Japan.
- Mathematics for Advances Materials Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Sendai 980-8577, Japan
| | - Jianbo Lin
- Center for Basic Research on Materials, National Institute for Materials Science, Tsukuba 305-0047, Japan
| | - Yasunori Futamura
- Department of Computer Science, University of Tsukuba, Tsukuba 305-8573, Japan
- Center for Artificial Intelligence, University of Tsukuba, Tsukuba 305-8573, Japan
- Master's/Doctoral Program in Life Science Innovation, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Tetsuya Sakurai
- Department of Computer Science, University of Tsukuba, Tsukuba 305-8573, Japan
- Center for Artificial Intelligence, University of Tsukuba, Tsukuba 305-8573, Japan
- Master's/Doctoral Program in Life Science Innovation, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Ryo Tamura
- Center for Basic Research on Materials, National Institute for Materials Science, Tsukuba 305-0047, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8568, Japan
| | - Tsuyoshi Miyazaki
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-8568, Japan.
- Master's/Doctoral Program in Life Science Innovation, University of Tsukuba, Tsukuba 305-8577, Japan
- Graduate School of Engineering, Nagoya university, Nagoya 464-8603, Japan
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Louzguine-Luzgin DV. Structural Changes in Metallic Glass-Forming Liquids on Cooling and Subsequent Vitrification in Relationship with Their Properties. MATERIALS (BASEL, SWITZERLAND) 2022; 15:7285. [PMID: 36295350 PMCID: PMC9610435 DOI: 10.3390/ma15207285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 09/30/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
The present review is related to the studies of structural changes observed in metallic glass-forming liquids on cooling and subsequent vitrification in terms of radial distribution function and its analogues. These structural changes are discussed in relationship with liquid's properties, especially the relaxation time and viscosity. These changes are found to be directly responsible for liquid fragility: deviation of the temperature dependence of viscosity of a supercooled liquid from the Arrhenius equation through modification of the activation energy for viscous flow. Further studies of this phenomenon are necessary to provide direct mathematical correlation between the atomic structure and properties.
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Affiliation(s)
- D. V. Louzguine-Luzgin
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Aoba-Ku, Sendai 980-8577, Japan;
- MathAM-OIL, National Institute of Advanced Industrial Science and Technology (AIST), Sendai 980-8577, Japan
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