Binbin Weng

Long‐term atmospheric monitoring sites provide the observations used to evaluate greenhouse‐gas inventories and constrain atmospheric inversions. The Southern Great Plains (SGP) observatory, among the most heavily utilized sites in the U.S. Department of Energy Atmospheric Radiation Measurement program, has exhibited persistently elevated methane (CH ₄ ) that existing bottom‐up inventories cannot explain. Combining multi‐year tower observations (2011–2024) with a mobile campaign (June 2024), we trace these CH ₄ enhancements to a large animal feeding operation 5.8 km from the site. Mass‐balance estimates yield emission rates of 59–79 kg hr ⁻¹ , exceeding the EDGAR v8.0 agricultural CH ₄ for the surrounding 0.1° grid cell (∼4 kg hr ⁻¹ ) by more than an order of magnitude. Strongly stable nocturnal boundary layers recurrently trap these emissions near the surface, producing CH ₄ enhancements exceeding 300 ppb within the lowest 25 m. These findings demonstrate that underestimated point sources, amplified by boundary‐layer trapping, can dominate signals at sites relied upon for inventory validation. Regional inversions that assimilate such local records without resolving the underlying source may systematically overestimate the emissions in the surrounding area.

PbS quantum dots (QDs) are highly promising visible–near‐infrared materials for low‐noise broadband photodetectors, particularly in a state‐of‐the‐art homojunction device made solely from p‐ and n‐doped QDs. However, the performance of these QD photodetectors is frequently bottlenecked by the inferior quality of p‐doped PbS QDs. This limitation originates from the poor ligand control of p‐doped QDs during the constrained and incomplete solid‐phase synthesis, resulting in significant energy‐level disorder and aggravated carrier recombination in the device. Here, we propose an ethylenediamine (EDA) post‐treatment strategy to refine the ligand environment of p‐doped PbS QDs after synthesis. This EDA treatment efficiently removes the residual insulating oleate ligands by 91.4%, while promoting further bonding of the target thiol ligands. The mild chemical nature of EDA ensures that pre‐deposited functional layers remain entirely unaffected. Photodetectors incorporating EDA‐treated p‐doping QDs exhibit significantly suppressed noise (3.07 × 10 ⁻¹⁴ A Hz ^−1/2 ) and achieve an ultrawide bandwidth of 205 kHz for high‐speed operation. These high‐performance detectors enable rapid and clear broadband single‐pixel imaging through various opaque media, demonstrating their considerable potential for machine vision, autonomous sensing, and imaging under challenging environments.

Portable breath-based smoking detectors rely on carbon monoxide (CO) sensing, yet they remain vulnerable to environmental interference and user-induced artifacts such as incomplete breaths or ambient air contamination. To address this reliability gap, we introduce a temperaturedifferential breath-verification method that distinguishes genuine human exhalations from environmental air based on the characteristic temperature rise during a breath event. The approach integrates baseline hold-breath temperature, peak exhalation temperature, and Δ thresholds to automatically assess breath validity before CO values are processed or reported. We implement this framework on a compact, battery-powered IoT platform featuring duty-cycled CO sensing, BLE communication, and onboard environmental monitoring. Although the system operates at ultra-low power, the primary contribution of this work is the real-time data-quality assurance mechanism, which uses temperature dynamics—not CO concentration—to authenticate breath events. Experimental evaluations demonstrate that Δ reliably differentiates valid breaths from ambient samples, significantly improving robustness without additional hardware or battery cost. This Δ -based breath-verification strategy provides a generalizable path toward more trustworthy portable respiratory sensing systems.

Tailoring light–matter interactions is crucial for advancing nanophotonics. Surface phonon polaritons are promising candidates for enhanced light–matter interactions due to their efficient, low-loss light confinement. In this work, we experimentally investigate the Reststrahlen bands in sapphire across the infrared spectrum, spanning ω = 385–1050 cm⁻¹. We extended this investigation to nanocone-patterned sapphire resonators, with specific attention to its in-plane and out-of-plane permittivity components. Infrared spectroscopy and full-wave simulations revealed a range of optical excitations, including three surface phonon polaritons with quality factors as high as 40 ± 1, two hyperbolic volume phonon polaritons with quality factors as high as 83 ± 4, and one epsilon-near-zero mode with a quality factor of 122 ± 8 across the various Reststrahlen bands. Furthermore, confocal Raman scattering measurements showed enhanced Raman signals with maximum enhancement factors of 7.0 ± 0.6 on the nanostructured surface, indicating coupling between phonons and phonon–polaritons. Finally, finite element modeling of polarizability demonstrates good quantitative agreement with the measured results. This study is the first exploration of sapphire nanostructures and gives an in-depth understanding of phonon polaritons and epsilon-near-zero modes from nanocone-structured sapphire. The reported Raman enhancement attributed to coupling of phonon and phonon polariton modes holds promise for sensing through surface-enhanced Raman spectroscopy.

A Digital Twin (DT) framework to enhance carbon-based gas plume monitoring is critical for supporting timely and effective mitigation responses to environmental hazards such as industrial gas leaks, or wildfire outbreaks carrying large carbon emissions. We present AIMNET, a one-of-a-kind DT framework that integrates a built-in-house Internet of Things (IoT)-based continuous sensing network with a physics-based multi-scale weather-gas transport model, that enables high-resolution and real-time simulation and detection of carbon gas emissions. AIMNET features a three-layer system architecture: (i) physical world: custom-built devices for continuous monitoring; (ii) bidirectional information feedback links: intelligent data transmission and reverse control; and (iii) digital twin world: AI-driven analytics for prediction, anomaly detection, and dynamic weather-gas coupled molecule transport modeling. Designed for scalable, energy-efficient deployment in remote environments, AIMNET architecture is realized through a small-scale distributed sensing network over an oil and gas production basin. To demonstrate the high-resolution, fast-responding concept, an equivalent mobile-based emission monitoring network was deployed around a wastewater treatment plant that constantly emits methane plumes. Our preliminary results through which, have successfully captured the methane emission events whose dynamics have been further resolved by the tiered model simulations. This work supports our position that AIMNET provides a promising DT framework for reliable, real-time monitoring and predictive risk assessment. In the end, we also discuss key implementation challenges and outline future directions for advancing such a new DT framework for translation deployment.

Surface phonon polaritons (SPhPs) are promising candidates for enhanced light--matter interactions due to their efficient and low-loss light confinement features. In this work, we present unique light-matter interactions in saphhire within its Reststrahlen bands (RBs) across the long-wave infrared (LWIR) spectrum ($ω= 385$-$1050~\mathrm{cm}^{-1}$). Particularly, we investigated the nanocone-patterned sapphire resonator array, with specific attention to its in-plane and out-of-plane permittivity components. Through Fourier transform infrared spectroscopy measurement and full-wave photonic simulations, we identified a range of optical excitations in the RBs, including three SPhPs, two hyperbolic volume phonon polaritons (HVPhPs), and one epsilon-near-zero (ENZ) mode. The depth-resolved confocal Raman spectroscopy revealed strongly enhanced Raman signals on the nanostructured surface, suggesting the mode coupling between phonons and phonon-polaritons, which was further confirmed by the finite element modeling of polarizability. This exploratory study provides in-depth insights into the dynamics of LWIR phonon polaritons and ENZ modes in the nanostructured sapphire, indicating its great potential for innovative nanophotonic applications.