Xinghai Liu

Photoactivated room-temperature phosphorescence (RTP) provides a promising platform for ink-free photoprinting and time-resolved information storage, but efficient organic RTP under ambient conditions is strongly limited by oxygen quenching. Here, four carbazole-derived chromophores were dispersed in a transparent PMMA matrix to construct color-tunable photoactivated RTP films. Upon 365 nm UV irradiation, the films were converted from weakly emissive states into bright persistent afterglow. Among them, 7BCz/PMMA exhibited the best performance, showing a 378-fold enhancement in phosphorescence intensity, a luminance of 27.73 cd m-2, and a lifetime of 1.255 s after 30 s irradiation. Spectroscopic studies indicate that UV irradiation promotes the formation of photogenerated radicals, which further mediate local oxygen depletion and suppress oxygen-induced triplet quenching within the rigid PMMA matrix. The resulting bright and erasable afterglow enables QR code writing, pattern rewriting, and thermal erasure, demonstrating its potential for rewritable ink-free photoprinting and optical anticounterfeiting.

Conventional source term estimation algorithms for elevated point sources are limited to single-source scenarios, failing to provide rapid and accurate quantification of multiple simultaneous releases during industrial accidents. Moreover, the classical Gaussian plume model exhibits poor adaptability under dynamic meteorological conditions and multi-source coupling. To overcome these limitations, as well as the premature convergence and long runtime of traditional particle swarm optimization (PSO) and its improved variant AHPSO, this paper proposes a fast source term estimation method based on an improved adaptive heterogeneous particle swarm optimization (Fast-AHPSO) tailored for emergency response. A multi-source coupled Gaussian plume correction model is developed by incorporating wind field functions, superposition mechanisms, and temperature–humidity corrections to enhance dispersion simulation accuracy for accidental releases. The Fast-AHPSO algorithm reduces computational time through less frequent altruistic operations and an early stopping mechanism. Experimental results show that Fast-AHPSO achieves high-precision source strength estimation under both clustered and dispersed source layouts, with average relative errors of 1.29\% and 0.22\%, respectively. Its runtime is approximately one-tenth that of AHPSO, greatly improving efficiency for real-time decision-making. The spatial distribution of sources significantly affects inversion accuracy: dispersed configurations yield smoother concentration fields and smaller gradients, leading to more accurate estimates. This study provides an efficient and reliable tool for rapid source term estimation of multiple elevated releases in industrial zones, with important implications for process safety enhancement and emergency response planning.

Coherent-dispersion spectroscopy enables high-precision Doppler measurements of stellar spectral lines, which serves as a vital technique for the indirect detection of exoplanets. In this study, the post-dispersion system of a coherent-dispersion spectrometer (CODES) was designed and optimized using Zemax, with the detection spectral range of 656 nm–716 nm and a spectral resolution of 0.06 nm. The relay optical path adopted a combination of a cylindrical lens group and an image slicer, which reshaped the circular spot with a diameter of 630 μm into a linear spot of 27 μm × 2038.8 μm, effectively matching the slit size and improving the light throughput. A flat-field design was employed for the dispersion module, which adopted two structures: the Czerny–Turner spectrometer and the Dyson spectrometer. Both spectrometer structures were designed and optimized, and their aberrations and structural characteristics were comparatively analyzed. The on-axis Modulation Transfer Function (MTF) values at the central wavelength of the two spectrometers were 0.4@37 lp/mm and 0.8@37 lp/mm, respectively, and both the spectral resolution and imaging resolution could meet the design requirements. This work provides a feasible design idea for high-precision CODES for exoplanet detection as well as general medium-to-high resolution spectrometers.

The development of sustainable flexible electronics is hindered by a lack of sensing materials that synergize eco‐friendliness, robust mechanical properties, and reliable electromechanical responsiveness. While starch‐based hydrogels present a promising sustainable alternative, their widespread application is limited by inherent brittleness and significant signal hysteresis. Here, a molecular engineering strategy is proposed to address these limitations. Porous starch is first obtained through a gradual solvent exchange process to enhance chain accessibility. Protocatechuic acid (PCA) is then covalently grafted onto the starch backbone via EDC/NHS‐mediated esterification, introducing dynamic hydrogen‐bonding and π − π interaction motifs. By optimizing the ratio between PCA‐modified starch and polyacrylamide (PAM), a bioinspired hydrogel with exceptional toughness and rapid electromechanical response is achieved. The resultant hydrogel exhibited pronounced strain‐dependent resistance behavior, enabling its integration into a wireless wearable human‐machine interface. To ensure robust decoding against motion‐induced noise, a finite state machine (FSM)‐based algorithm is employed for adaptive signal segmentation, achieving a character‐level accuracy of 99.2% in trials with healthy subjects ( n = 10). This work not only introduces a high‐performance, sustainable hydrogel platform but also demonstrates a practical route toward inclusive and language‐independent human‐machine communication.

A multifunctional hydrogel capable of both wet‐state microwave absorption and dry‐state phosphorescence is designed. Incorporating Cu‐doped carbon dots (Cu _x ‐CDs) into a polyacrylamide/carboxymethyl cellulose (PAM/CMC) network enables synergistic modulation of electromagnetic and optical behaviors. Cu doping effectively regulates the hydrogen‐bond network and water state within the hydrogel, promoting charge migration and dipolar polarization, thereby significantly enhancing dielectric loss and absorption efficiency. The optimized hydrogel exhibits a minimum reflection loss of −62.67 dB and an effective absorption bandwidth of 5.94 GHz within the 2–18 GHz range. Density functional theory (DFT) calculations reveal that Cu‐N coordination reduces the energy gap and enhances electronic delocalization, facilitating charge transfer. Upon dehydration, the polymer network reconstructs into a dense and rigid framework that suppresses nonradiative transitions, yielding stable blue and green room‐temperature phosphorescence. Such a transition from wet‐state absorption to dry‐state emission, driven by Cu doping and hydrogen‐bond engineering, provides a new paradigm for constructing stimuli‐responsive hydrogels. This work offers a versatile strategy for designing multifunctional materials with potential applications in electromagnetic protection, information encryption, and optical anti‐counterfeiting.

Achieving long-lived room-temperature phosphorescence (RTP) with high quantum efficiency is of significant interest for applications in anti-counterfeiting, flexible optoelectronic displays, and multi-level information encryption. Here, we presented a hydrogen-bond engineering strategy to enhance RTP performance by progressively increasing the number of hydrogen-bonding sites within a polyvinyl alcohol (PVA) matrix. A series of carbazole-based chromophores (Cz, ICz and 2ICz) were embedded into the PVA network, and their photophysical properties were systematically characterized using steady-state photoluminescence spectra, time-decay spectra, Fourier-transform infrared (FTIR), and Raman and X-ray photoelectron spectroscopy (XPS). Spectroscopic analysis revealed that the increased number of N-H groups significantly strengthened hydrogen-bonding interactions, effectively suppressing non-radiative decay pathways and stabilizing triplet excitons. As a result, the phosphorescence lifetime was prolonged up to 1.68 s with a quantum yield of 38.63%. Furthermore, leveraging the spectral overlap integral between the phosphorescent emission and dye absorption, efficient Förster resonance energy transfer (FRET) was realized, enabling tunable multi-color afterglow emissions. This study establishes a design strategy validated by spectroscopy for high-performance RTP materials and highlights their promising potential in advanced optical encryption and flexible photonic applications.

Accurate and rapid detection of urinary creatinine (CR) is critical for early kidney disease screening and efficient healthcare resource management. In this study, a novel colorimetric‐fluorescent sensor is developed by integrating nitrogen‐doped carbon dots (N‐CDs) and copper nanoclusters (CuNCs) with gold nanoparticles (AuNPs), leveraging fluorescence resonance energy transfer (FRET) to enhance sensitivity and selectivity. The sensor functions within a detection range of 1–50 m m , with peak responsiveness at 17 m m , utilizing paper‐based substrates for a low‐cost and portable application. Additionally, the sensor demonstrates excellent stability, high selectivity, and strong resistance to interference from other substances, ensuring accurate detection of CR in complex samples. These findings indicate that the dual‐probe system significantly improves detection accuracy and operational simplicity compared to traditional CR measurement techniques. This innovative sensor offers a promising platform for rapid, on‐site CR analysis, facilitating early diagnosis and effective monitoring of kidney diseases in diverse settings.