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Satellite-based solar-induced chlorophyll fluorescence (SIF) serves as a valuable proxy for monitoring the photosynthesis of vegetation globally. The Global Ozone Monitoring Experiment-2A (GOME-2A) SIF product has gained widespread popularity, particularly due to its extensive global coverage since 2007. However, serious temporal degradation of the GOME-2A instrument is a problem, and there is currently a lack of time-consistent GOME-2A SIF products that meet the needs of temporal trend analysis. In this paper, the GOME-2A instrument's temporal degradation was first calibrated using a pseudo-invariant method, which revealed 16.21 % degradation of the GOME-2A radiance at the near-infrared (NIR) band from 2007 to 2021. Based on the calibration results, the temporal degradation of the GOME-2A radiance spectra was successfully corrected by using a fitted quadratic polynomial function whose determination coefficient (R2) was 0.851. Next, a data-driven algorithm was applied for SIF retrieval at the 735–758 nm window. Also, a photosynthetically active radiation (PAR)-based upscaling model was employed to upscale the instantaneous clear-sky observations to monthly average values to compensate for the changes in cloud conditions and atmospheric scattering. Accordingly, a global temporally consistent GOME-2A SIF dataset (TCSIF) for 2007 to 2021 with the correction of temporal degradation was successfully generated, and the spatiotemporal pattern of global SIF was then investigated. Corresponding trend maps of the global temporally consistent GOME-2A SIF showed that 62.91 % of vegetated regions underwent an increase in SIF, and the global annual averaged SIF exhibited a trend of increasing by 0.70 % yr−1 during the 2007–2021 period. The TCSIF dataset is available at https://doi.org/10.5281/zenodo.8242928 (Zou et al., 2023).

Water-soluble humic-like substances (HULIS) absorb light in near-UV and visible wavelengths and exert significant influence on the atmospheric environment and climate. However, knowledge on HULIS evolution during haze bloom-decay process is limited. Herein, PM2.5 samples were obtained during a winter haze event in Guangzhou, China, and the light absorption and molecular composition of HULIS were investigated by UV–Vis spectrophotometry and ultrahigh-resolution mass spectrometry. Compared with HULIS on clean days, the absorption coefficients (Abs365) of HULIS on haze days were significantly higher but the mass absorption efficiencies (MAE365) were relatively low, suggesting diverse and dynamic absorption properties of HULIS during haze episodes. The CHO and CHON compounds were the most abundant components in HULIS, followed by CHOS, CHONS, and CHN. Haze HULIS presented comparatively high molecular weight; a lower aromaticity index (AImod); and higher O/Cw, O/Nw, and O/Sw ratios, indicating that HULIS fractions undergo relatively high oxidation during haze days compared to clean days. Moreover, CHON and CHO compounds with high AImod were the major potential chromophores in HULIS and significantly contributed to HULIS light absorption. It is worth noting that the proportions of these chromophores decreased during haze events, mainly owing to their higher oxidation during haze episodes. Besides, accumulated contribution of organic compounds emitted from vehicles and formed from reactions of biogenic volatile organic compounds (bio-VOCs) also diluted light-absorbing compounds in haze HULIS. These findings help us to understand HULIS evolution during haze bloom-decay processes in the subtropic region of China.

Biomass burning (BB) and coal combustion (CC) are important sources of brown carbon (BrC) in ambient aerosols. In this study, six biomass materials and five types of coal were combusted to generate fine smoke particles. The BrC fractions, including water-soluble organic carbon (WSOC), humic-like substance carbon (HULIS-C), and methanol-soluble organic carbon (MSOC), were subsequently fractionated, and their optical properties and chemical structures were then comprehensively investigated using UV–visible spectroscopy, proton nuclear magnetic resonance spectroscopy (1H NMR), and fluorescence excitation–emission matrix (EEM) spectroscopy combined with parallel factor (PARAFAC) analysis. In addition, the oxidative potential (OP) of BB and CC BrC was measured with the dithiothreitol (DTT) method. The results showed that WSOC, HULIS-C, and MSOC accounted for 2.3 %–22 %, 0.5 %–10 %, and 6.4 %–73 % of the total mass of combustion-derived smoke PM2.5, respectively, with MSOC extracting the highest concentrations of organic compounds. The MSOC fractions had the highest light absorption capacity (mass absorption efficiency at 365 nm (MAE365): 1.0–2.7 m2/gC) for both BB and CC smoke, indicating that MSOC contained more of the strong light-absorbing components. Therefore, MSOC may represent the total BrC better than the water-soluble fractions. Some significant differences were observed between the BrC fractions emitted from BB and CC with more water-soluble BrC fractions with higher MAE365 and lower absorption Ångström exponent values detected in smoke emitted from BB than from CC. EEM-PARAFAC identified four fluorophores: two protein-like, one humic-like, and one polyphenol-like fluorophores. The protein-like substances were the dominant components of WSOC (47 %–80 %), HULIS-C (44 %–87 %), and MSOC (42 %–70 %). The 1H-NMR results suggested that BB BrC contained more oxygenated aliphatic functional groups (H-C-O), whereas CC BrC contained more unsaturated fractions (H-C-C= and Ar−H). The DTT assays indicated that BB BrC generally had a stronger oxidative potential (DTTm, 2.6–85 pmol/min/µg) than CC BrC (DTTm, 0.4–11 pmol/min/µg), with MSOC having a stronger OP than WSOC and HULIS-C. In addition, HULIS-C contributed more than half of the DTT activity of WSOC (63.1 % ± 15.5 %), highlighting that HULIS was a major contributor of reactive oxygen species (ROS) production in WSOC. Furthermore, the principal component analysis and Pearson correlation coefficients indicated that highly oxygenated humic-like fluorophore C4 may be the important DTT active substances in BrC.

Aiming at the properties of Fe and SiO2 in nickel slag, the process of preparing DRI by direct reduction nickel slag from coal base was proposed, and the component of gangue is used as raw material to prepare C2S(belite) and C3S(alite), which is a comprehensive utilization of nickel slag. The reduction reaction of iron coupling of the reaction of cementitious materials was realized through thermodynamic calculation and experiment. The reduction roasting products of nickel slag with iron, C3S and C2S as the main phase were obtained by reasonable batching and temperature control technology of reduction roasting reaction.

This paper presents a bottom-up methodology based on the local emission factors, complemented with the widely used emission factors of Computer Programme to Calculate Emissions from Road Transport (COPERT) model and near-real-time traffic data on road segments to develop a vehicle emission inventory with high temporal–spatial resolution (HTSVE) for the Beijing urban area. To simulate real-world vehicle emissions accurately, the road has been divided into segments according to the driving cycle (traffic speed) on this road segment. The results show that the vehicle emissions of NOx, CO, HC and PM were 10.54 × 104, 42.51 × 104 and 2.13 × 104 and 0.41 × 104 Mg respectively. The vehicle emissions and fuel consumption estimated by the model were compared with the China Vehicle Emission Control Annual Report and fuel sales thereafter. The grid-based emissions were also compared with the vehicular emission inventory developed by the macro-scale approach. This method indicates that the bottom-up approach better estimates the levels and spatial distribution of vehicle emissions than the macro-scale method, which relies on more information. Based on the results of this study, improved air quality simulation and the contribution of vehicle emissions to ambient pollutant concentration in Beijing have been investigated in a companion paper (He et al., 2016).

To investigate the behaviour of recycled aggregate concrete (RAC) under combined compression and shear stresses, 75 hollow cylinder specimens prepared with various replacement ratios of recycled coarse aggregate (RCA) were tested with a self-designed loading device. The results showed that the failure pattern was similar for RAC with different replacement ratios of RCA. The ultimate shear stress improved with an increasing axial compression ratio of less than 0.6 and declined after exceeding 0.6. A modified failure criterion for RAC with normal strength under combined compression and shear stresses was proposed. A new procedure to predict the shear strength for RAC beams without stirrups was developed based on the proposed failure criterion, showing a better correlation with the experimental results than the predictions calculated by GB50010, Eurocode 2, fib Model Code 2010 and ACI 318-11.

Intestinal obstruction leads to blockage of the movement of intestinal contents. After relieving the obstruction, patients might still suffer with compromised immune function and nutritional deficiency. This study aimed to evaluate the effects of Sijunzi decoction on restoring the immune function and nutritional status after relieving the obstruction. Experimental rabbits (2.5±0.2 kg) were randomly divided into normal control group, 2-day intestinal obstruction group, 2-day natural recovery group, 4-day natural recovery group, 2-day treated group, and 4-day treated group. Sijunzi decoction was given twice a day to the treated groups. The concentration of markers was analyzed to evaluate the immune function and nutritional status. The concentration of interleukin-2, immunoglobulins and complement components of the treated groups were significantly higher than the natural recovery group (P