A thermal phase transition has been resolved in gold nanoparticles supported on a surface. By use of asynchronous optical sampling with coupled femtosecond oscillators, the Lamb vibrational modes could be resolved as a function of annealing temperature. At a temperature of 104 degrees C the damping rate and phase changes abruptly, indicating a structural transition in the particle, which is explained as the onset of surface melting.
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http://dx.doi.org/10.1021/nl070187t | DOI Listing |
Nat Commun
December 2024
Department of Civil and Environmental Engineering, and Research Centre for Resources Engineering towards Carbon Neutrality, The Hong Kong Polytechnic University, Hong Kong, China.
The feasibility of carbon mineralization relies on the carbonation efficiency of CO-reactive minerals, which is largely governed by the water content and state within material mesopores. Yet, the pivotal role of confined water in regulating carbonation efficiency at the nanoscale is not well understood. Here, we show that the maximum CO intake occurs at an optimal relative humidity (RH) when capillary condensation initiates within the hydrophilic mesopores.
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December 2024
School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China.
Liquid crystal elastomers (LCEs) with various deformation properties based on phase transition were widely used as actuators and provided potential to fabricate functional surfaces with tunable microstructure. Herein, we demonstrate a strategy to fabricate dynamic micro wrinkles on LCE surfaces based on LC phase transition. Stable micron-sized surface wrinkles on the anthracene-containing LCE film (AnLCE) are fabricated by ultraviolet exposure induced gradient cross-linking and subsequently stretching-releasing (UV-SR).
View Article and Find Full Text PDFNat Commun
December 2024
Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA.
Geometric frustration in two-dimensional Ising models allows for a wealth of exotic universal behavior, both Ising and non-Ising, in the presence of quantum fluctuations. In particular, the triangular antiferromagnet and Villain model in a transverse field can be understood through distinct XY pseudospins, but have qualitatively similar phase diagrams including a quantum phase transition in the (2+1)-dimensional XY universality class. While the quantum dynamics of modestly-sized systems can be simulated classically using tensor-based methods, these methods become infeasible for larger lattices.
View Article and Find Full Text PDFJ Phys Chem B
December 2024
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
The cloud point temperatures of aqueous poly(-isopropylacrylamide) (PNIPAM) and poly(ethylene) oxide (PEO) solutions were measured from pH 1.0 to pH 13.0 at a constant ionic strength of 100 mM.
View Article and Find Full Text PDFAdv Mater
December 2024
Academy for Advanced Interdisciplinary Studies and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, P. R. China.
Concurrent superconductivity and negative photoconductivity (NPC) are rarely observed. Here, the discovery in PbSeTe of superconductivity and photoconductivity transitions between positive photoconductivity (PPC) and NPC during compression is reported to ≈40 GPa and subsequent decompression, which are also accompanied by reversible structure transitions (3D Fm m ⇌ 2D Pnma ⇌ 3D Pm m). Superconductivity with a maximum T of ≈6.
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