This paper focuses on the revelation of structural relationship of the ordered and disordered states in Cu-(Zr, Ti) binary systems. The atomic radial distributions in real space and the electron scattering behavior in reciprocal space between crystalline and amorphous phases are compared. The spherical-periodic order, characteristic of disordered structures, is clearly present in the crystalline phases, suggesting the structural homology of crystalline and the corresponding amorphous states. Furthermore, the diameters of Brillouin- or Jones-zones at the Fermi level in the crystalline and amorphous states are also similar and they fall close to those of the calculated Fermi spheres, verifying the resonance between the static atomic structure and the electron wave.
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http://dx.doi.org/10.1088/1361-648X/abba8b | DOI Listing |
Nanotechnology
January 2025
Walker Department of Mechanical Engineering, The University of Texas at Austin, 204 E. Dean Keeton St., Austin, Texas, 78712-1139, UNITED STATES.
Sapphire is an attractive material in photonic, optoelectronic, and transparent ceramic applications that stand to benefit from surface functionalization effects stemming from micro/nanostructures. Here we investigate the use of ultrafast lasers for fabricating nanostructures in sapphire by exploring the relationship between irradiation parameters, morphology change, and selective etching. In this approach an ultrafast laser pulse is focused on the sapphire substrate to change the crystalline morphology to amorphous or polycrystalline, which is characterized by examining different vibrational modes using Raman spectroscopy.
View Article and Find Full Text PDFSmall
January 2025
Dept. of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 7610001, Israel.
Transient amorphous phases are known as functional precursors in the formation of crystalline materials, both in vivo and in vitro. A common route to regulate amorphous calcium carbonate (ACC) crystallization is via direct interactions with negatively charged macromolecules. However, a less explored phenomenon that can influence such systems is the electrostatically driven formation of Ca-macromolecule dense phases.
View Article and Find Full Text PDFSci Rep
January 2025
Nonprofitable Organization Touche NPO, Sapporo, 060-004, Japan.
In this study, we explore the structural intricacies of cellulose, a polymer composed of glucose monomers arranged in a linear chain, primarily investigated through solid-state NMR techniques. Specifically, we employ low-field proton nuclear magnetic resonance (H-NMR) to delve into the diverse hydrogen atom types within the cellulose molecule. The low-field H-NMR technique allows us to discern these hydrogen atoms based on their distinct chemical shifts, providing valuable insights into the various functional groups present in cellulose.
View Article and Find Full Text PDFAppl Spectrosc
January 2025
Department of Chemistry, University of Utah, Salt Lake City, Utah, USA.
Crystallization from the melt is a critical process governing the properties of semi-crystalline polymeric materials. While structural analyses of melting and crystallization transitions in bulk polymers have been widely reported, in contrast, those in thin polymer films on solid supports have been underexplored. Herein, in situ Raman microscopy and self-modeling curve resolution (SMCR) analysis are applied to investigate the temperature-dependent structural changes in poly(ethylene oxide) (PEO) films during melting and crystallization phase transitions.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, Lodz 90-363, Poland.
This work is focused on the impact of temperature and deformation on the mechanical properties, specifically the elastic modulus () of the amorphous regions in semicrystalline polymers, using polypropylene as a case study. It has been shown that increasing temperature results in an decrease due to the enhanced mobility of polymer chains, triggered by the activation of α relaxation processes within the crystalline component. Consequently, rising temperature reduces the "stiffening" effect of the crystalline regions on the interlamellar layers.
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