摘要 : As the invasion of alien species intensifies, the native salt marsh vegetation, especially the ecosystem of Suaeda salsa ( S. salsa ), in Chinese coastal wetlands has been severely disrupted, significantly impeding its functionality within coastal wetland ecosystems. Chlorophyll content (C ab ) is an important parameter for monitoring the growth and health status of vegetation. However, the remote sensing mechanism of C ab for different phenotypes of green and red vegetation influenced by betacyanin under different water and salt conditions is not clear. Therefore, to further clarify the remote sensing mechanism of S. salsa and improve the generality of C ab prediction for different phenotypes under different water and salt conditions, we designed a growth experiment under different groundwater levels and salt concentrations. This experiment was used to simulate the growth of S. salsa in different habitats in nature and investigate the relationship between their physicochemical parameters, spectra, and environmental stress. We propose using the specific absorption coefficient of betacyanin (Beta) to adjust PROSAIL-D to better fit the spectral characteristics of S. salsa . The relationship between Beta and C ab was utilized to further optimize the simulation accuracy of the PROSAIL-D model in different environments. Feature extraction algorithms, including differential enhancement of two-dimensional correlation spectroscopy (FD-2DCOS) and three-band models, were introduced to construct multiple spectral features for establishing a C ab prediction model for S. salsa . The research results showed that: (1) S. salsa had the best response of C ab and spectra to salinity under a higher groundwater level and showed a gradual reddening trend. (2) The spectral curves simulated by the adjusted PROSAIL-D model were more consistent with the spectral characteristics of S. salsa under different water-salt environments, and the simulation effect could be further optimized by using the relationship between Beta and C ab . (3) The FD-2DCOS analysis method we proposed could highlight the useful spectral information related to C ab better than the original 2DCOS algorithm. The final eight spectral features of (1/R 701 –1/R 540 )R 540, Mean(D 590 – 600 ), Mean(D 660 – 670 ), Mean(D 677 – 685 ), FDVI_NRG, FDVI_NIR, Skewness (D 677 – 750 ) and Position(D 677 – 750 ) had the best response to C ab of S. salsa, and had the least influence on LAI and soil background. (4) The particle swarm optimization random forest regression (PSO-RFR) model based on eight spectral features and adding 70% measured spectral data performed the best in predicting the actual C ab of S. salsa, with an RMSE of 2.326 μg·cm −2 . Although further optimization and calibration of the adjusted PROSAIL-D model and C ab prediction model of S. salsa are needed in the future, this study extended its application to S. salsa, a special local salt marsh vegetation, and promoted the development of C ab monitoring of salt marsh vegetation in coastal wetlands.

摘要 : Capacity fading of Ni-rich cathode is thought to originate from the formation of inactive rock-salt phase induced by surface reactivity and the isolation of active material caused by microcracks due to anisotropic volume contraction of grains. It is generally assumed that inhibiting the formation of microcracks within secondary particle by radially aligned microstructure is a vital aspect for suppressing capacity fading. However, the new researches about reduction of microcracks simply by certain electrolytes call a question on the origin of microcracks and the critical factor for the cycle life of cathodes. Herein, LiNi 0.92 Co 0.04 Mn 0.04 O 2 cathodes with different surface characteristic and radially aligned microstructure were synthesized by doping with high valence elements using some hydroxide precursor. The effects of W 6+ and/or Mo 6+ induced surface phase and microstructure on electrochemical performance were investigated. Despite the inferior radially aligned, size-refined primary grains and higher degree of microcracks, W 6+ doped cathode still possesses alleviated parasitic reactions, higher crystal structural stability and capacity retention than Mo 6+ doped materials, because of the enhanced cathode-electrolyte interfacial stability. The results contend that the consequence of surface reactivity on determining cycle life of Ni-rich cathodes is more critical than that of microcracks, and efforts relating to constructing intact and uniform stable surface phase will exhibit greater potential to promote the performance of Ni-rich cathodes than microstructural refinement.

摘要 : Carbon aerogel is one of the ideal materials for supercapacitor because of its high specific surface area and high conductivity. Sodium carboxymethyl cellulose (CMC-Na) has attracted much attention owing to its water solubility. In this work, we have provided a simple and facile strategy by zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O) as an activative agent and urea (CO(NH 2 ) 2 ) as a nitrogen source to achieve the N/O co-doped carbon aerogels. Just as bread expands during baking, the introduction of these agents makes the materials expand and fluffy. By changing the amount of Zn(NO 3 ) 2 ·6H 2 O and CO(NH 2 ) 2, the microstructure and element content can be controlled. When the mass ratio of CMC-Na, Zn(NO 3 ) 2 ·6H 2 O and CO(NH 2 ) 2 was 2:1:4, we obtained the highest specific capacitance in a three-electrode system (248 F g −1 at 0.1 A g −1 ). This value was more than three times higher than that of pure CMC-Na derived carbon materials. In the symmetrical supercapacitor, the maximum specific capacitance was 129 F g −1 at 0.1 A g −1 . It was assembled into a coin cell for long cycle stability test and the capacitance retention maintained 90 % at 30 A g −1 for 15, 000 cycles. Compared with the traditional method of carbonization followed by activation, this work exhibits a simpler strategy by one-step carbonization and activation and shows the prospect of CMC-Na as a precursor of the carbon electrode in the field of energy storage.

摘要 : Organic membrane fouling is a major obstacle to the application of membrane distillation in low surface tension wastewater treatment. Membrane modification might be an effective way to mitigate membrane fouling. This study mainly explored the mechanism of enhanced anti-fouling performance of the MXene modified PVDF membrane by applying XDLVO theory combined with surface elemental integration (SEI) method. The rough membrane surfaces were first reconstructed using fractal function. Then, the interaction energy between low surface tension substances and the membranes before and after modification was calculated. The results showed that oil droplets and surfactant fouling were mainly caused by hydrophobic attraction due to Lewis acid-base (AB) interaction energy. By modifying the virgin PVDF membrane with MXene nanoparticles, the polar component of membrane surface tension (γAB) increased significantly, so that the interaction energy between all contaminants and membrane surface changed from attraction to repulsion. In addition, roughness weakened the interaction energy between contaminants and membrane surface but significantly lengthened the range of interaction distance, which together determined the ability of the membrane to attract or repel the contaminants. These findings may improve the understanding of the structure-effect relationship between membrane modification and anti-fouling ability, and provide new insights into the membrane modification for MD.

摘要 : Remaining useful life (RUL) prediction of rolling bearing is one of the important measures to ensure the reliable operation of mechanical equipment. Most of the existing methods are domain adaptation (DA) based RUL prediction on the same machine with different conditions, but few on cross-machine. DA can cope with the data distribution discrepancy (domain shift) under different machines or other conditions, but the potential negative transfer will affect the effect of DA and prediction performance. Therefore, an enhanced residual convolutional domain adaptation network (ERCDAN) is designed for cross-machine rolling bearing RUL prediction. Firstly, the enhanced residual convolutional module (ERCM) is designed for degradation feature extraction from limited data, and with the convolutional block attention module (CBAM) to enhance the extracted features. Secondly, the DA module with a collaborative full connection structure and attenuation multi-kernel maximum mean discrepancy is designed for mitigating negative transfer to effective domain-invariant feature extraction. Finally, the experimental analysis of cross-machine rolling bearing RUL prediction is conducted on the PHM2012, XJTU-SY, and EBFL datasets. The results show that the proposed method can not only effectively achieve cross-machine RUL prediction, but also has good cross-bearing prediction performance with different conditions on the same machine, reflecting good generalization performance.

摘要 : The desorption of surface-adsorbed organic matter (S-AOM) without damaging algal cells was reported to be the key to destabilizing Microcystis aeruginosa ( M. aeruginosa ) cells while avoiding intracellular organic matter (IOM) release in our previous study. However, a temporal effect was found from spontaneous and continuous damage to algal cells even after quenching. This study aims to demonstrate the mechanism of the temporal inactivation effect and the stress response exhibited by chlorine-oxidized algal cells, and finally guide the prechlorination process for algae-laden water at water sources. Chlorine was proved to cause oxidative stress to M. aeruginosa cells, and result in a rapid increase in intracellular reactive oxygen species (ROS) levels. S-AOM appeared to have a protective effect on algal cells against oxidative damage, as evidenced by the maintenance of algal cell integrity and activated antioxidant enzymes. In addition, the activity of Caspase 3, a key protease for the execution of programmed cell death (PCD), was significantly enhanced during prechlorination. Cellular chromatin condensation and DNA fragmentation occurred in the early stages of PCD in algal cells. Therefore, the pre-treatment of algae-laden water at water sources, even with low chlorine doses, can induce a risk of significant algal cell death during the water transfer process due to activation of the PCD process, resulting in a higher health risk for drinking water. These findings indicate that both the dosage of chlorine and the duration of the transportation process should be considered during the prechlorination of algae-laden water, which can provide an important basis for avoiding increasing the risk to drinking water safety.

摘要 : The cycloaddition reaction of CO 2 in traditional reactors is relatively slow due to insufficient gas–liquid contact. In this work, the microdroplet reactor was set up to research the intensification effect of increasing the volumetric mass transfer coefficient on the reaction. The [C 1 C 2 Im][I]/PhOH (1-ethyl-3-methylimidazolium iodide/Phenol) with a molar ratio of 2:1 exhibited excellent catalytic activity at room temperature. Up to 85% conversion of the substrate could be achieved in the microdroplet intensification device. The intensification reaction model of the microdroplet was established, which explored the effect of the microdroplet size and gas–liquid mass transfer on the reaction. The increase of the volumetric mass transfer coefficient ( k La ) could improve the efficiency of the reaction at the gas–liquid interface of the microdroplet. The mathematical model of the microdroplet intensification reaction was established to clarify the intensification mechanism.

摘要 : Recently, there has been a growing trend in utilizing waste rubber as a partial replacement for aggregates in concrete. This approach not only promotes the reuse of waste rubber but also addresses the shortage of natural aggregates. An issue arising from various compositions between rubber and the cement matrix is the accurate prediction and control of the mechanical properties of rubber concrete, which impedes the widespread application of rubber concrete because the indispensable on-site mechanical tests are time-consuming and labor-intensive. In response to this challenge, an integrated AI-based approach that enables the real-time prediction of the compressive strength of rubber concrete through mobile devices was proposed. Firstly, a U-Net-based semantic segmentation model is employed to identify different compositions within cross-section photos of rubber concrete. Subsequently, an artificial neural network (ANN) model is adopted to promptly and precisely predict the compressive strength of rubber concrete using the proportions of the semantic segmentation compositions. The proposed approach is validated through a database based on past experimental results. The U-Net-based component recognition model achieves an accuracy of 89.31 %, while the strength prediction model attains an accuracy of 82.08 %. Overall, this method effectively identifies various compositions and establishes a correlation between their proportions and the compressive strength of rubber concrete. This provides a partially explainable and efficient approach for the widespread on-site application of rubber concrete.

摘要 : Developing a stable MOF-modified membrane for efficient treatment of oily wastewater remains a challenge. In this study, NH 2 -MIL-88B(Fe) (NM88B) was deposited on the commercial polyvinylidene fluoride (PVDF) membranes, and grafted with perfluorohexane-1-sulfonic acid potassium salt (PFHx) to achieve quaternization modification. This reaction proceeds in an environmentally friendly manner due to the absence of any catalyst. The introduction of fluorine atoms through grafting PFHx resulted in the modified PVDF membrane (NPF) demonstrating remarkable underwater superoleophobic property with an underwater oil contact angle at ∼180°. In separation of various oil-water emulsions, the NPF membrane afforded a high permeation flux (up to 2043 L·m −2 ·h −1 ) and rejection rate (∼99 %). The oil rejection of NPF membrane was >99 % after 10 filtration cycles of n -hexadecane-water emulsion, and the pure water flux of the recovered membrane was kept at 82.65 % of the original flux, indicating a very good reusability and stability. Filtration of mixed dye/oil-water emulsions showed that the NPF membrane remove 99 % of both oil and dye from the mixture. This work provides a simple and stable modification of PVDF membrane, exhibiting remarkable underwater superoleophobicity and hydrophilicity, thereby harboring substantial prospects in the treatment of oily wastewater.

摘要 : Herein, glyoxylic acid (GA) was incorporated into the Fenton-like (Fe(III)/H 2 O 2 ) system to rigorously examine its impact on the degradation of organic pollutants . It was found that the degradation efficiencies of atrazine (ATR), ofloxacin (OFL), rhodamine B (RhB), and carbamazepine (CBZ) in the Fe(III)/GA/H 2 O 2 system were ∼95%, and the apparent ATR degradation rate constant (1.60 × 10 −2 min −1 ) was 4-fold as high as that (0.40 × 10 −2 min −1 ) in the Fe(III)/H 2 O 2 system at pH 3.6. The UV–vis spectral and cyclic voltammetry (CV) analyses demonstrated that GA could be used as a ligand and reductant to coordinate and reduce Fe(III), thereby promoting the Fe(III)/Fe(II) cycles in the Fenton-like process. Testing results for reactive oxygen species (ROS) confirmed that superoxide ions (•O 2 – ) and hydroxyl radicals (•OH) respectively undertake the Fe(III)/Fe(II) cycles and ATR degradation in the Fe(III)/GA/H 2 O 2 system. The reaction stoichiometric efficiencies (RSE) in the Fe(III)/GA/H 2 O 2 system (37.5%–76.9%) were significantly higher than those (2.8%–4.9%) in the Fe(III)/H 2 O 2 system within 180 min, and the maximum concentration of •OH in the Fe(III)/GA/H 2 O 2 system was 4.6 times that in the Fe(III)/H 2 O 2 system. A series of the important variables were optimized in detail, including solution pH, GA dosage, amount of Fe(III) and H 2 O 2 . These findings provide compelling evidence for the non-negligible role of GA in the processes of organic pollutants degradation based on the Fe(III)/Fe(II) cycles and radicals generation in the Fenton-like system.