Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2026022502
This study investigates the effects of different land use types on topsoil carbon (C) and nitrogen (N) contents and their spatial distribution in the lower reaches of the Sancha River Basin, a karst region of the Yunnan-Guizhou Plateau. Grid sampling collected 0–20 cm topsoil from forestland (n=23), cultivated land (n=25), and grassland (n=32). Total C and N were measured. Results showed that topsoil C content followed grassland (40.36±22.92 g·kg−1) > forestland (37.05±12.83 g·kg−1) > cultivated land (34.06±14.57 g·kg−1), while N content followed forestland (2.89±0.76 g·kg−1) > grassland (2.67±1.19 g·kg−1) > cultivated land (2.50±0.65 g·kg−1). One-way ANOVA revealed no significant differences among land use types (P>0.05). Soil C and N were significantly positively correlated across all land uses (r>0.5, P<0.001). Coefficient of variation (CV) indicated grassland had the highest C variability (0.57), while forestland showed the most stable C and N (CV=0.35 and 0.26, respectively). Cultivated land had CVs of 0.43 for C and 0.26 for N. Spatially, forestland exhibited concentrated high C values with significant N heterogeneity; grassland had higher C in southern and eastern areas but scattered distribution, with generally low and variable N; cultivated land showed uniform but lowest C and N. Land use types significantly drive topsoil C and N dynamics through vegetation input, soil disturbance, and management practices, underscoring the importance of rational land use planning for enhancing carbon sink functions and sustainable development in karst watersheds.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3920-1
Lead-free halide perovskites are promising scintillators due to strong X-ray attenuation and high internal quantum efficiency (IQE), but their application is hindered by moisture sensitivity. Here, CsSrCl3:Eu2+ nanocrystals were grown in situ in a specially designed inorganic glass matrix. By employing [PO4]-modification and controlled crystallization, a transparent CsSrCl3:Eu2+ glass-ceramic (GC) scintillator was obtained, combining high crystallinity (15.9%) with excellent optical transparency (85.3% at 432 nm). The GC exhibits outstanding photoluminescence (PL) performance, including a high IQE of 87.6% and superior thermal stability (74% intensity retention at 493 K relative to 303 K). Benefiting from the robust glass matrix, the GC retains 99% of its initial PL intensity after 14 days of water immersion. Under X-ray excitation, it shows blue X-ray excited luminescence (XEL), with peak and integrated intensities reaching 117% and 25.1% of those of Bi4Ge3O12 crystal, respectively. The scintillator achieves a high spatial resolution of 20 lp mm−1 and an X-ray detection limit of 3.7 μGy s−1. Furthermore, it demonstrates exceptional operational stability in humid environments, maintaining clear X-ray image contrast even after 48 h of water submersion. This study provides an effective strategy for stabilizing hygroscopic halide scintillators in a durable [PO4]-modified fluoroaluminate glass matrix and demonstrates the potential of CsSrCl3:Eu2+ GC for high-resolution and stable X-ray imaging.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4040-0
High-performance organic second-order nonlinear optical (NLO) crystals face a persistent challenge: molecular designs that enhance hyperpolarizability often crystallize into centrosymmetric or nonpolar arrangements, suppressing bulk second-order response, while simultaneously reducing optical bandgaps, enforcing a trade-off between nonlinearity and transparency. We report a chirality-driven polar lattice engineering strategy that couples molecular asymmetry with directional intermolecular interactions to promote polar ordering. A binaphthyl-based chromophore (S-3) crystallizes in the polar space group P2₁, exhibiting strong second-harmonic generation (~3.53 × KDP), wide transparency (3.91 eV), phase-matchable birefringence (Δn = 0.15), high laser damage threshold (742.6 MW cm⁻²), and thermal stability up to 210 °C. Theoretical calculations reveal a 69% enhancement in first-order hyperpolarizability (β_tot) relative to the unfunctionalized derivative, with a net intramolecular electron transfer of 0.16 e⁻ from the chiral scaffold to the benzoate acceptor. Crucially, enantiomeric crystals exhibit identical NLO responses, confirming that bulk nonlinearity is governed by engineered lattice polarity, not molecular handedness. This work establishes chirality as an active tool for crystal engineering and provides a general design paradigm for high-performance organic NLO materials.