| 1. |
- Hadjiev, V. G., et al.
(författare)
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Symmetry of phonon, magnetic, and spin-phonon excitations in GdSr2RuCu2O8 single crystals
- 2001
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 64
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Tidskriftsartikel (refereegranskat)abstract
- We present a polarized Raman scattering study of GdSr2RuCu2O8 single crystals. In this compound, the RuO6 octahedra are rotated around the c axis that in turn gives some Raman activity of the oxygen (O-Ru) vibrations at 265 cm(-1) (A(1g)), 411 cm(-1) (B-2g) and 607 cm(-1) (B-1g). These vibrations, as well as those of the apical oxygen of RuO6, at 654 cm(-1) (A(1g)) and the Cu-plane oxygen at 318 cm(-1) (B-2g), clearly respond to the onset of magnetic ordering at T-m approximate to 140 K. In particular, the 265 cm(-1) mode hardens anomalously with decreasing temperature below T-m. Notably, the corresponding phonon line is absent in the Raman spectra of GdSr2NbCu2O8 (Nb5+:4d(0)), a compound isomorphic to GdSr2RuCu2O8 (Ru5+:4d(3)). We argue that the eigenvector of the 265 cm(-1) phonon (rotational mode) facilitates efficient modulation of the Ru(t(1g))-O-Ru (p) bands. This modulation gives both Raman scattering strength to the 265 cm(-1) mode and strong spin-phonon coupling.
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| 2. |
- He, W., et al.
(författare)
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Deep learning-assisted flexible piezoresistive sensor with liquid-phase reduced metal electrodes for fitness movement recognition and correction
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 495
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Tidskriftsartikel (refereegranskat)abstract
- Flexibility and wearability in electronic devices gain prominence with the rise of national fitness campaigns. Among them, piezoresistive sensors stand out for their ability to accurately monitor health signals due to their high sensitivity. However, conventional metal nanoparticle ink electrodes face issues like peeling, chemical instability, and substrate limitations. This study introduces a novel method for fabricating high-performance flexible piezoresistive sensors using liquid-phase reduced metal electrodes. Integration of porous polydimethylsiloxane (PDMS) substrates with highly conductive interdigital silver electrodes (1.6 × 10−6 Ω·m) addresses conventional electrode shortcomings, offering permeability, flexibility, and outstanding conductivity. Incorporation of a graphene (GR)/carbon nanotube (CNT)/Ecoflex composite enhances sensor piezoresistive sensing capabilities, with features including high sensitivity (3.57 KPa−1), rapid response time (58 ms/72 ms), and excellent cycle stability (>10000 cycles). The sensor finds utility in various applications, including human physiological signal monitoring, pressure array recognition, and handwriting recognition. Additionally, with deep learning techniques, the system achieves accurate recognition (99.25 %) and correction (98.75 %) of diverse fitness movements, aiming to promote safer exercise practices, enhance training efficiency, and advance intelligent wearable fitness devices.
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