The quantities entropy and diffusion are measured for two- and three-dimensional (3D) dust clusters in the fluid state. Entropy and diffusion are predicted to be closely linked via unstable modes. The method of instantaneous normal modes is applied for various laser-heated clusters to determine these unstable modes and the corresponding diffusive properties. The configurational entropy is measured for 2D and 3D clusters from structural rearrangements. The entropy shows a threshold behavior at a critical temperature for the 2D clusters, allowing us to estimate a configurational melting temperature. Further, the entropic disorder increases for larger clusters. Finally, the predicted relation between entropy and unstable modes has been confirmed from our experiments for 2D systems, whereas 3D systems do not show such a clear correlation.
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http://dx.doi.org/10.1103/PhysRevE.87.063102 | DOI Listing |
J Chem Phys
January 2025
State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
Identifying the diverse roles of disorderly packed atoms inside an amorphous solid has been a highly pursued but daunting task in glass physics. By analyzing the full-frequency vibrational modes of a model Cu50Zr50 glass, here, we classify the internal atoms into low-, subhigh-, and high-frequency ones that have different tendencies for rearrangements upon excitations. We find that low-frequency atoms are structurally unfavored and tend to aggregate.
View Article and Find Full Text PDFSe Pu
February 2025
Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, Shanghai 200237, China.
Thromboxane A (TXA), a prothrombotic factor that induces platelet aggregation and thrombosis, acts as a vasoconstrictor by activating TXA receptors (TP receptors). TXA is extremely unstable and metabolizes into three major metabolites: 2,3-dinor thromboxane B (2,3-dinor-TXB), 11-dehydro TXB(11-dh-TXB), and 11-dehydro-2,3-dinor TXB(11-dh-2,3-dinor-TXB). 8-Iso-prostaglandin F(8-iso-PGF), a prostaglandin-like compound widely considered the best biomarker of oxidative stress, can also activate TP receptors.
View Article and Find Full Text PDFThe genome replication of SARS-CoV-2, the causative agent of COVID-19, involves a multi-subunit replication complex consisting of non-structural proteins (nsps) 12, 7 and 8. While the structure of this complex is known, the dynamic behavior of the subunits interacting with RNA is missing. Here we report a single-molecule protein-induced fluorescence enhancement (SM-PIFE) assay to monitor binding dynamics between the reconstituted or co-expressed replication complex and RNA.
View Article and Find Full Text PDFChaos
January 2025
School of Mathematics and Statistics, Jiangsu Normal University, Xuzhou 221116, China.
We demonstrate that fundamental nonlinear localized modes can exist in the Chen-Lee-Liu equation modified by several parity-time (PT) symmetric complex potentials. The explicit formula of analytical solitons is derived from the physically interesting Scarf-II potential, and families of spatial solitons in internal modes are numerically captured under the optical lattice potential. By the spectral analysis of linear stability, we observe that these bright solitons can remain stable across a broad scope of potential parameters, despite the breaking of the corresponding linear PT-symmetric phases.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
Time-reversal symmetry breaking of a topological insulator phase generates zero-field edge modes which are the hallmark of the quantum anomalous Hall effect (QAHE) and of possible value for dissipation-free switching or non-reciprocal microwave devices. But present material systems exhibiting the QAHE, such as magnetically doped bismuth telluride and twisted bilayer graphene, are intrinsically unstable, limiting their scalability. A pristine magnetic oxide at the surface of a TI would leave the TI structure intact and stabilize the TI surface, but epitaxy of an oxide on the lower-melting-point chalcogenide presents a particular challenge.
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