Morphology evolution at microscopic scales has an inseparable relationship with surface material behaviors, especially during ultrasmooth surface fabrication. In this work, the influence of initially existing local densification on ion nanopatterning of a fused-silica surface is investigated. Our research results indicate that fused-silica surfaces will easily densify permanently under a compressive load, exhibiting an anisotropic surface at the nanoscale. During the subsequent ion-beam sputtering process, the densification-dependent sputtering would influence and even dominate surface morphology evolution, which is identified as being an important evolution mechanism. However, ion-induced relaxation mechanisms will overcome surface roughening in the absence of local densification, and an ultrasmooth surface with root mean square roughness down to 0.06 nm is obtained in our experiment.
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http://dx.doi.org/10.1364/AO.53.002487 | DOI Listing |
J Chem Phys
January 2025
Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, Centre Telč, 58856 Telč, Czech Republic.
The time-evolution of dynamics as well as microstructure and mechanical response of phosphate-based geopolymers was probed using x-ray photon correlation spectroscopy and rheological tests. The analyzed relaxation processes in the freshly prepared geopolymer mixes evidenced a q-independent mode of the autocorrelation function, ascribed to density fluctuations of the already established molecular network, undergoing reconfiguration without significant mass transport. Upon curing, the detected motions are localized and depict a system evolving toward structural arrest dominated by slower hyperdiffusive dynamics, characterized by a compressed exponential regime, pointing to a structural relaxation process subjected to internal stresses, in a context of marked dynamical and structural heterogeneity.
View Article and Find Full Text PDFNano Lett
January 2025
Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China.
Developing sustainable structural materials to replace traditional carbon-intensive structural materials fundamentally reshapes the concept of circular development. Herein, we propose an interface engineering strategy that utilizes water as a liquid medium to replace the residual air within natural wood. This approach minimizes the absorption of water-based softening agents by microcapillary channels of wood, enabling the controlled softening of the cell walls.
View Article and Find Full Text PDFNanomaterials (Basel)
November 2024
Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, Rue du Doyen Georges Poitou, 91405 Orsay, France.
This study investigates the structural and optical responses of silica glass to femtosecond (fs) laser irradiation followed by high-energy electron (2.5 MeV, 4.9 GGy) irradiation.
View Article and Find Full Text PDFHealth Place
December 2024
Te Kura Neehi | School of Nursing, Waipapa Taumata Rau | University of Auckland, Tāmaki Makaurau, Auckland, New Zealand. Electronic address:
This scoping review explores the relationship between urban density and child health and wellbeing, focusing on how urban density has been measured and its association with various child health outcomes. By analysing 53 studies spanning from 1972 to 2023, we identify significant variability in how urban density is defined and measured and mixed evidence regarding its relationship with different child health outcomes. We also highlight context-specific findings, which may be connected to a range of dynamic and interconnected local and socio-cultural factors.
View Article and Find Full Text PDFSci Total Environ
December 2024
Department of Geoinformation in Environmental Management, Mediterranean Agronomic Institute of Chania, Chania, Crete 73100, Greece.
A growing concern in the Mediterranean region is that recent landcover and land use change is increasing wildfire risk, or the exposure and impacts of wildfire to valued resources. However, the magnitude of these effects is not well understood given the widely diverse landscapes of communities, natural vegetation, and agricultural land. In this study, we use wildfire simulation modeling to assess how landcover and land use changes in three areas of southern Greece have affected exposure of- and fire risk to- communities and economically important permanent agriculture such as Olea europaea (European olive) orchards.
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