Polyolefins represent the largest fraction of global plastic waste, yet their chemical inertness poses a major challenge for recycling. In this study, normal‑alkane modeling was employed to investigate the catalytic transformation of linear alkyl chains over two Pt‑modified zeolites, Pt/USY and Pt/ZSM‑5, using n‑dodecane and n‑nonane as representative long‑ and short‑chain analogs. Comprehensive characterization revealed that Pt dispersion and zeolite pore topology jointly modulate acidity and metal-acid synergy, thereby steering product selectivity and reaction pathways. Pt/USY, with its larger pore volume and moderate acidity, promoted dehydrogenation and cracking, yielding higher fractions of alkenes and branched alkanes while suppressing excessive aromatization. In contrast, Pt/ZSM‑5 exhibited stronger hydrogenation activity, converting olefinic intermediates into saturated alkanes and cycloalkanes while reducing aromatic formation. Comparative analysis of n‑dodecane and n‑nonane demonstrated that longer alkyl chains undergo deeper cracking and secondary reactions, leading to higher yields of light hydrocarbons, aromatics, and coke, whereas shorter chains are less reactive and more resistant to cyclization. Both Pt‑modified catalysts showed reduced coke deposition relative to their parent zeolites. These findings provide mechanistic insights into Pt–zeolite synergy and chain‑length effects, offering guidance for the rational design of advanced catalysts to enable efficient chemical recycling of polyolefin wastes into tailored fuels and chemicals.
Strong interactions between particles can lead to emergent collective excitations. Spin waves, known as magnons, have been predicted to reach a strongly interacting hydrodynamic regime, where they form a slow collective density mode. In this work, we isolate exfoliated sheets of chromium trichloride (CrCl3), where magnon interactions are strong, and develop a technique to measure the collective magnon dynamics though nearby nitrogen-vacancy centers in diamond. Thermal magnetic fluctuations generated by monolayer CrCl3 increase upon decreasing temperature; this anomalous trend may be a consequence of the damping rate of a low-energy magnon sound mode that sharpens as magnon interactions increase with increasing temperature. By measuring the magnetic fluctuations emitted by thin multilayer CrCl3 in the presence of a variable-frequency drive field, we obtain spectroscopic evidence for this two-dimensional magnon sound mode.
This paper aims to develop a theory of projective and affine structures on higher-dimensional varieties in positive characteristic. This theory deals with Frobenius-projective and Frobenius-affine structures, which have been previously investigated in the case where the underlying space is a curve. We first provide a description of such structures in terms of Berthelot's higher-level differential operators. That description leads us to obtain a positive characteristic version of Gunning's formulas, which give necessary conditions on Chern classes for the existence of Frobenius-projective and Frobenius-affine structures, respectively. Finally, we establish some characterizations of projective spaces using Frobenius-projective structures.
This paper addresses reflection removal, which is the task of separating reflection components from a captured image and deriving the image with only transmission components. Considering that the existence of the reflection changes the polarization state of a scene, some existing methods have exploited polarized images for reflection removal. While these methods apply polarized images as the inputs, they predict the reflection and the transmission directly as non-polarized intensity images. In contrast, we propose a polarization-to-polarization approach that applies polarized images as the inputs and predicts "polarized" reflection and transmission images using two sequential networks to facilitate the separation task by utilizing the interrelated polarization information between the reflection and the transmission. We further adopt a recurrent framework, where the predicted reflection and transmission images are used to iteratively refine each other. Experimental results on a public dataset demonstrate that our method outperforms other state-of-the-art methods.
In this paper, we study edge rings and their h-polynomials. We investigate when edge rings are pseudo-Gorenstein, which means that the leading coefficients of the h-polynomials of edge rings are equal to 1. Moreover, we compute the h-polynomials of a special family of edge rings and show that some of them are almost Gorenstein.
