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Abstract The electronics industry is rapidly advancing toward the development of highly miniaturized sensors and circuits, driving an increasing demand for precise, localized manufacturing techniques. Extrusion-based additive manufacturing—particularly direct ink writing—has emerged as a promising method for fabricating microscale electronic components. Recent efforts have focused on producing fine-resolution structures capable of conformal deposition on complex or uneven surfaces. While prior studies have established theoretical models for the trajectory of non-conductive material jets under electric fields—demonstrating feasibility in printing high-resolution features—a theoretical framework for conductive ink behavior under similar conditions remains lacking. This study introduces a theoretical model to describe the behavior of conductive jet extrusion under varying electrostatic forces. The model is validated through high-speed physical and manufacturing experiments using poly(3,4-ethylene-dioxythiophene)-based ink. The results demonstrate that the application of an external electric field significantly broadens the printable window, enabling: (i) high-speed printing up to 1.7 m/s with successful deposition on rough textile substrates (average surface roughness Ra = 8 µm), and (ii) the formation of micro-sized lines with widths as small as ∼60% of the nozzle's inner diameter (e.g., 300 µm-wide lines printed using a 500 µm diameter nozzle). 

Abstract During December 2022–January 2023, nine atmospheric rivers (ARs) struck California consecutively, causing catastrophic flooding and 600+ landslides. The extensive footprints of landslide‐triggering storms and their diverse hydrometeorological forcings highlight the urgent need to incorporate regional‐scale hydrometeorology into landslide research. Here, using a meteorologically‐informed hydrologic model, we simulate the time‐evolving water budget during the nine‐AR event and identify hydrometeorological conditions that contributed to widespread landslide occurrences across California. Our analysis reveals that 89% of observed landslides occurred under excessively wet conditions, driven by precipitation exceeding the capacities of infiltration, storage, evapotranspiration, and soil drainage. Using K‐means clustering, we identify three distinct hydrometeorological pathways that increased landslide potential: intense precipitation‐induced runoff (∼32% of reported landslides), rain on pre‐wetted soils (∼53%), and snowmelt and soil ice thawing (∼15%). Our findings highlight the importance of constraining the compounding factors that influence slope stability over spatial scales consistent with landslide‐triggering weather systems. 

Posted to the preprint archive ( https://arxiv.org/abs/2505.20159 ) ; to be submitted soon 

Structural defects in one-dimensional heat conductors couple longitudinal (stretching) and transverse (bending) vibrations. This coupling results in the scattering of longitudinal phonons to transverse phonons and backward. We show that the decay rate of longitudinal phonons due to this scattering scales with their frequencies as ω3/2 within the long wavelength limit (ω → 0), which is a more efficient scattering compared to the traditionally considered Rayleigh scattering within the longitudinal band (ω2). This scattering results in temperature-independent thermal conductivity, depending on the size as κ ∝ L1/3 for sufficiently long materials. This predicted length dependence is observed in nanowires, although the temperature dependence seen there is possibly because of deviations from pure one-dimensional behavior. The significant effect of interaction of longitudinal phonons with transverse phonons is consistent with the earlier observations of a substantial suppression of thermal energy transport by kinks, obviously leading to such interaction, although anharmonic interaction can also be significant. 

Accepted for publication in Physical Review B 

ABSTRACT: Carbenes and carbenoids are commonly employed for the synthesis of cyclopropane-containing compounds. Here we report the metal-free, intramolecular cyclopropanation of tethered alkenes by free carbenes derived from alkynes to construct structurally unique, multicyclic cyclopropanes with perfect atom economy. The nature of the tether influences both the rate of carbene formation as well as subsequent competing reaction events. Some of the substrates lead to metastable cyclopropane intermediates that further fragment to furnish interesting isomeric products by mechanistically novel processes. A removable siloxane tether can be utilized to achieve formal intermolecular cyclopropanations and to access cyclopropanol derivatives. 

Molecular vibrations are generally responsible for chemical energy transport and dissipation in molecular systems. This transport is fast and efficient if energy is transferred by optical phonons in periodic oligomers, but its efficiency is limited by decoherence emerging due to anharmonic interactions with acoustic phonons. Using a general theoretical model, we show that in the most common case of the optical phonon band being narrower than the acoustic bands, decoherence takes place in two stages. The faster stage involves optical phonon multiple forward scattering due to absorption and emission of transverse acoustic phonons, i.e., collective bending modes with a quadratic spectrum; the transport remains ballistic and the speed can be altered. The subsequent slower stage involves phonon backscattering in multiphonon processes involving two or more acoustic phonons resulting in a switch to diffusive transport. If the initially excited optical phonon possesses a relatively small group velocity, then it is accelerated in the first stage due to its transitions to states propagating faster. This theoretical expectation is consistent with the recent measurements of optical phonon transport velocity in alkane chains, increasing with increasing the chain length.