Chong Rae Park

Small-angle X-ray scattering (SAXS) probes both open and closed porosity, but quantitative size analysis of dense carbons is hindered by inter-pore interference, merged voids, and the absence of absolute calibration in many laboratory datasets. We recast the problem as a scale-resolved void-volume budget. The Porod invariant is partitioned into logarithmic q-band invariants and inverted through a band–size operator using non-negative Tikhonov regularization. Relative spectra are independent of intensity scale and contrast, whereas absolute porosity requires an external anchor. Dense-medium effects are incorporated through first-order operators calibrated on simulated Boolean penetrable-grain structures. For synthetic media at φ ≈ 0.35, the calibrated operator reduces the total-porosity error from −45.7% for the dilute operator to −6.1 ± 6.1% over ten realizations, with a spectrum error of 26.1 ± 12.2%. Error-weighted Monte Carlo tests show that full-curve inversion is superior for detailed shape recovery when an exact forward model is available, whereas band integration provides lower dispersion in integral porosity budgets and greater tolerance to residual background. The method is applied to uncalibrated 2004 SAXS data for four round-robin activated carbons. Re-analysis identifies an incorrect size-axis integration in the original workflow and recovers micro/mesopore fractions consistent with archived N2-DFT benchmarks, including 99.4% versus 99.0% microporosity for an activated carbon fabric and 37/63 versus 37/63 micro/mesoporosity for a mesoporous carbon. The approach provides an explicitly bounded framework for band-based, scale-resolved porosity analysis when pointwise forward models or absolute calibration are unavailable.

Small-angle X-ray scattering (SAXS) probes both open and closed porosity, but quantitative size analysis of dense carbons is hindered by inter-pore interference, merged voids, and the absence of absolute calibration in many laboratory datasets. We recast the problem as a scale-resolved void-volume budget. The Porod invariant is partitioned into logarithmic q-band invariants and inverted through a band–size operator using non-negative Tikhonov regularization. Relative spectra are independent of intensity scale and contrast, whereas absolute porosity requires an external anchor. Dense-medium effects are incorporated through first-order operators calibrated on simulated Boolean penetrable-grain structures. For synthetic media at φ ≈ 0.35, the calibrated operator reduces the total-porosity error from −45.7% for the dilute operator to −6.1 ± 6.1% over ten realizations, with a spectrum error of 26.1 ± 12.2%. Error-weighted Monte Carlo tests show that full-curve inversion is superior for detailed shape recovery when an exact forward model is available, whereas band integration provides lower dispersion in integral porosity budgets and greater tolerance to residual background. The method is applied to uncalibrated 2004 SAXS data for four round-robin activated carbons. Re-analysis identifies an incorrect size-axis integration in the original workflow and recovers micro/mesopore fractions consistent with archived N2-DFT benchmarks, including 99.4% versus 99.0% microporosity for an activated carbon fabric and 37/63 versus 37/63 micro/mesoporosity for a mesoporous carbon. The approach provides an explicitly bounded framework for band-based, scale-resolved porosity analysis when pointwise forward models or absolute calibration are unavailable.

Lightweight structural materials are commonly used as effective fillers for advanced composites with high toughness. This study focused on enhancing the toughness of direct‐spun carbon nanotube yarns (CNTYs) by controlling the micro‐textural structure using a water‐gap‐based direct spinning. Drawing inspiration from the structural features of natural spider silk fibroin, characterized by an α‐helix in the amorphous region and β‐sheet in the crystalline region, multiscale bundles within CNTYs are reorganized into a unique nano‐coil‐like structure. This nano‐coiled structure facilitated the efficient dissipation of external mechanical loads through densification with the rearrangement of multiscale bundles, improving specific strength and strain. The resulting CNTYs exhibited exceptional mechanical properties with toughness reaching 250 J g⁻¹, making them promising alternatives to commercially available fibers in lightweight, high‐toughness applications. These findings highlight the significance of nano‐coiling engineering for emulating bio‐inspired micro‐textural structures, achieving remarkable enhancement in the toughness of CNTYs.

Correction for ‘Large-scalable, ultrastable thin films for electromagnetic interference shielding’ by Jae Seo Park et al., J. Mater. Chem. A, 2023, https://doi.org/10.1039/D3TA02862C.