Pixel Distillation: Cost-flexible Distillation across Image Sizes and Heterogeneous Networks.

Previous knowledge distillation (KD) methods mostly focus on compressing network architectures, which is not thorough enough in deployment as some costs like transmission bandwidth and imaging equipment are related to the image size. Therefore, we propose Pixel Distillation that extends knowledge distillation into the input level while simultaneously breaking architecture constraints. Such a scheme can achieve flexible cost control for deployment, as it allows the system to adjust both network architecture and image quality according to the overall requirement of resources. Specifically, we first propose an input spatial representation distillation (ISRD) mechanism to transfer spatial knowledge from large images to student's input module, which can facilitate stable knowledge transfer between CNN and ViT. Then, a Teacher-Assistant-Student (TAS) framework is further established to disentangle pixel distillation into the model compression stage and input compression stage, which significantly reduces the overall complexity of pixel distillation and the difficulty of distilling intermediate knowledge. Finally, we adapt pixel distillation to object detection via an aligned feature for preservation (AFP) strategy for TAS, which aligns output dimensions of detectors at each stage by manipulating features and anchors of the assistant. Comprehensive experiments on image classification and object detection demonstrate the effectiveness of our method.

Microcapsule Modification Strategy Empowering Separator Multifunctionality to Enhance Safety of Lithium-Metal Batteries.

The uncontrollable growth of lithium dendrites and the flammability of electrolytes are the direct impediments to the commercial application of high-energy-density lithium metal batteries (LMBs). Herein, this study presents a novel approach that combines microencapsulation and electrospinning technologies to develop a multifunctional composite separator (P@AS) for improving the electrochemical performance and safety performance of LMBs. The P@AS separator forms a dense charcoal layer through the condensed-phase flame retardant mechanism causing the internal separator to suffocate from lack of oxygen. Furthermore, it incorporates a triple strategy promoting the uniform flow of lithium ions, facilitating the formation of a highly ion-conducting solid electrolyte interface (SEI), and encouraging flattened lithium deposition with active SiO2 seed points, considerably suppressing lithium dendrites growth. The high Coulombic efficiency of 95.27% is achieved in Li-Cu cells with additive-free carbonate electrolyte. Additionally, stable cycling performance is also maintained with a capacity retention rate of 93.56% after 300 cycles in LFP//Li cells. Importantly, utilizing P@AS separator delays the ignition of pouch batteries under continuous external heating by 138 s, causing a remarkable reduction in peak heat release rate and total heat release by 23.85% and 27.61%, respectively, substantially improving the fire safety of LMBs.

[Finite element analysis of the impact of bone mass and volume of low-density area under tibial plateau on lower limb alignment].

Objective: To investigate the impact of the bone mass and volume of the low-density area under the tibial plateau on the lower limb force line by finite element analysis, offering mechanical evidence for preventing internal displacement of the lower limb force line in conjunction with knee varus in patients with knee osteoarthritis (KOA) and reducing bone mass under the tibial plateau. Methods: A healthy adult was selected as the study subject, and X-ray film and CT imaging data were acquired. Mimics 21.0 software was utilized to reconstruct the complete knee joint model and three models representing low-density areas under the tibial plateau with equal volume but varying shapes. These models were then imported into Solidworks 2023 software for assembly and verification. Five KOA finite element models with 22%, 33%, 44%, 55%, and 66% bone mass reduction in the low-density area under tibial plateau and 5 KOA finite element models with 81%, 90%, 100%, 110%, and 121% times of the low-density area model with 66% bone mass loss were constructed, respectively. Under physiological loading conditions of the human lower limb, the distal ends of the tibia and fibula were fully immobilized. An axial compressive load of 1 860 N, following the lower limb force line, was applied to the primary load-bearing area on the femoral head surface. The maximum stress within the tibial plateau, as well as the maximum displacements of the tibial cortical bone and tibial subchondral bone, were calculated and analyzed using the finite element analysis software Abaqus 2022. Subsequently, predictions regarding the alteration of the lower limb force line were made based on the analysis results. Results: The constructed KOA model accorded with the normal anatomical structure of lower limbs. Under the same boundary conditions and the same load, the maximum stress of the medial tibial plateau, the maximum displacement of the tibial cortical bone and the maximum displacement of the cancellous bone increased along with the gradual decrease of bone mass in the low-density area under the tibial plateau and the gradual increase in the volume of the low-density area under tibial plateau, with significant differences ( P<0.05). Conclusion: The existence of a low-density area under tibial plateau suggests a heightened likelihood of knee varus and inward movement of the lower limb force line. Both the volume and reduction in bone mass of the low-density area serve as critical initiating factors. This information can provide valuable guidance to clinicians in proactively preventing knee varus and averting its occurrence.

Position-based anchor optimization for point supervised dense nuclei detection.

Nuclei detection is one of the most fundamental and challenging problems in histopathological image analysis, which can localize nuclei to provide effective computer-aided cancer diagnosis, treatment decision, and prognosis. The fully-supervised nuclei detector requires a large number of nuclei annotations on high-resolution digital images, which is time-consuming and needs human annotators with professional knowledge. In recent years, weakly-supervised learning has attracted significant attention in reducing the labeling burden. However, detecting dense nuclei of complex crowded distribution and diverse appearances remains a challenge. To solve this problem, we propose a novel point-supervised dense nuclei detection framework that introduces position-based anchor optimization to complete morphology-based pseudo-label supervision. Specifically, we first generate cellular-level pseudo labels (CPL) for the detection head via a morphology-based mechanism, which can help to build a baseline point-supervised detection network. Then, considering the crowded distribution of the dense nuclei, we propose a mechanism called Position-based Anchor-quality Estimation (PAE), which utilizes the positional deviation between an anchor and its corresponding point label to suppress low-quality detections far from each nucleus. Finally, to better handle the diverse appearances of nuclei, an Adaptive Anchor Selector (AAS) operation is proposed to automatically select positive and negative anchors according to morphological and positional statistical characteristics of nuclei. We conduct comprehensive experiments on two widely used benchmarks, MO and Lizard, using ResNet50 and PVTv2 as backbones. The results demonstrate that the proposed approach has superior capacity compared with other state-of-the-art methods. In particularly, in dense nuclei scenarios, our method can achieve 95.1% performance of the fully-supervised approach. The code is available at https://github.com/NucleiDet/DenseNucleiDet.

BMAnet: Boundary Mining With Adversarial Learning for Semi-Supervised 2D Myocardial Infarction Segmentation.

Automatic segmentation of myocardial infarction (MI) regions in late gadolinium-enhanced cardiac magnetic resonance images is an essential step in the computed diagnosis of myocardial infarction. Most of the current myocardial infarction region segmentation methods are based on fully supervised deep learning. However, cardiologists' annotation of myocardial infarction regions in cardiac magnetic resonance images during the diagnosis process is time-consuming and expensive. This paper proposes a semi-supervised myocardial infarction segmentation. It consists of two models: 1) a boundary mining model and 2) an adversarial learning model. The boundary mining model can solve the boundary ambiguity problem by enlarging the gap between the foreground and background features, thus segmenting the myocardial infarction region accurately. The adversarial learning model can make the boundary mining model learn from additional unlabeled data by evaluating the segmentation performance and providing pseudo supervision, which significantly increases the robustness of the boundary mining model. We conduct extensive experiments on an in-house myocardial magnetic resonance dataset. The experimental results on six evaluation metrics demonstrate that our method achieves excellent results in myocardial infarction segmentation and outperforms the state-of-the-art semi-supervised methods.

A novel approach simultaneously imparting well-hydrophobicity and photothermal conversion effect to polymer materials: solar-promoted absorption of organic solvents and oils.

In this work, a series of polymer materials including pomelo peel, cotton fabric, polyurethane foam, and so on, are treated by heated CH3SiCl3, presenting desirable photo-thermal conversion function and hydrophobicity. As a representative material, the surface element and skeleton morphology of pomelo peel foam treated by CH3SiCl3 are analyzed detailedly. It is found that well-hydrophobicity (water contact angle of ~147°) and photo-thermal conversion performance (~91.2 °C under one sun) are attributed to the surface carbonization reaction and formation of CH3-SiO2 nanoparticles. Meanwhile, the treatment of CH3SiCl3 significantly increases the BET surface area to 3.0635 m²/g from 0.0973 m²/g. Therefore, pomelo peel-derived carbon foam presents a desirable adsorption capacity of organic solvents and oils (up to 43.2 times its original weight) and excellent removal efficiency (>99.0%). In addition, the rapid photo-thermal response (achieve ~73 °C at 40 s) and high equilibrium temperature (~91.2 °C) are als° demonstrated in pomelo peel-derived carbon foam. As a result, the absorption rate of highly-viscous oils is effectively promoted by the higher fluidity and capillary action caused by the solar-promoted mechanism. This study offers a scalable, easily operated, and environmentally friendly approach to prepare hydrophobic and photo-thermal materials, thus demonstrating a huge potential in oil/water separation application.

[Optical Composition and Potential Driving Factors of Chromophoric Dissolved Organic Matter in Large Lakes and Reservoirs in the Eastern Region of China].

Intensified urbanization has been occurring in the eastern region of China in recent decades, and excessive industrial and household sewage has been discharged into lakes and reservoirs, which has directly lowered water quality and destructed the functions of aquatic ecosystems. Lakes and reservoirs are typically drinking water sources supplying water for metropolitan areas as well as large- and medium-sized cities. Chromophoric dissolved organic matter (CDOM) is the colored fraction of DOM, and its source and optical composition strongly affect water supply safety and the health of surrounding citizens. In April 2021, we collected 68 samples from Reservoir Changtan (n=11), Lake Taihu (n=25), Lake Hongze (n=18), and Lake Gaoyou (n=14), and we further carried out 28 days of laboratory bio-incubation, together with optical measurements and parallel factor analysis (EEMs-PARAFAC) to analyze the bio-degradability ω(BDOC), sources, and optical composition of CDOM in these waters. The results showed that after 28 days of laboratory bio-incubation, the bioavailability of dissolved organic carbon (BDOC) of the four lakes and reservoirs were all higher than 50%. PARAFAC results showed that CDOM collected from the four lakes was composed of four fluorescent components, including a terrestrial humic-like C1, a tryptophan-like C2, and tyrosine-like C3 and C4. Protein-like components (C2, C3, and C4) contributed importantly to the CDOM pool in the four waterbodies, and in Lake Hongze the contribution of C2-C4 was as high as (90.0±2.2)%. In Lake Hongze, total phosphorus (TP) correlated closely with C1-C3, indicating that those components can be used to trace the variability of TP. Among the four waterbodies, a254 was positively correlated with DOC (R2=0.96, P<0.01), indicating that a254 can be used to estimate the dynamics of DOC in these waters. In Lake Taihu, we found a low level of humification index (HIX) and a high level of biological index (BIX), indicating that autochthonous substances contributed importantly to the CDOM pool in this lake. In comparison, allochthonous sources contributed importantly to the CDOM pool in the remaining three waters. The enhanced monitoring of the discharge of industrial and agricultural effluents in the upstream watersheds of the four waters can help to protect the water quality and maintain healthy aquatic ecosystems.

Spatially non-stationary relationships between urbanization and the characteristics and storage-regulation capacities of river systems in the Tai Lake Plain, China.

Given environmental or hydrological functions influenced by changing river networks in the development of rapid urbanization, a clear understanding of the relationships between comprehensive urbanization (CUB) and river network characteristics (RNC), storage capacity (RSC), and regulation capacity (RRC) is urgently needed. In the rapidly urbanized Tai Lake Plain (TLP), China, various methods and multisource data were integrated to estimate the dynamics of RNC, RSC, and RRC as well as their interactions with urbanization. The bivariate Moran's I methods were applied to detect and visualize the spatial dependency of RNC, RSC, or RRC on urbanization. Geographically weighted regression (GWR) model was set up to characterize spatial heterogeneity of urbanization influences on RNC, RSC and RRC. Our results indicated that RNC, RSC and RRC variables each showed an overall decreasing trend across space from 1960s to 2010s, particularly in those of tributary rivers. RNC, RSC, or RRC had globally negative correlations with CUB, respectively, but looking at local scale the spatial correlations between each pair were categorized as four types: high-high, high-low, low-low, and low-high. GWR was identified to accurately predict the response of most RNC, RSC, or RRC variables to CUB (R2: 0.6-0.8). The predictive ability of GWR was spatially non-stationary. The obtained relationships presented different directions and strength in space. All variables except for the water surface ratio (Wp) were more positively affected by CUB in the middle eastern parts of TLP. Drainage density, RSC and RRC variables were more negatively influenced by CUB in the northeast compared to other parts. The quantitative results of spatial relationships between urbanization and RNC, RSC or RRC can provide location-specific guidance for river environment protection and regional flood risk management.

[Influences of Hydrological Scenarios on the Bioavailability, Fate, and Balance of Chromophoric Dissolved Organic Matter in Lake Poyang].

Lake Poyang has significant differences in hydrological characteristics between the flood and dry seasons. Unraveling the optical composition, bioavailability, fate, and balance of chromophoric dissolved organic matter (CDOM) and organic carbon fluxes in Lake Poyang under different hydrological conditions can help provide advanced schemes on carbon cycling, the transfer and transformation of organic matter, and water resource management of the lake. Three fluorescent components, including a humic-like (C1), a tryptophan-like (C2), and a tyrosine-like (C3) component, were obtained using three-dimensional fluorescence spectroscopy coupled with parallel factor analysis. Prior to and after 28 days of laboratory biodegradation, the means of a254 and the terrestrial humic-like (C1) component in the flood season were both significantly higher than that in the dry season (t-test, P<0.01), indicating that the terrestrial humic-like (C1) component contributed importantly to the CDOM pool. The contribution percentages of protein-like components in the dry season were 81.7% of the summed fluorescent components of CDOM, indicating that there might be discharge of domestic wastewater from areas surrounding the lake in the dry season. The bioavailabilities of the humic-like (C1) component and DOC were 14.0% and 43.2%, respectively, in the dry season. This can be explained by a declined-dilution effect in the lake during the dry rather than in the flood season. We observed no significant difference in the bioavailability of protein-like components under different hydrological conditions. The bioavailability of C1 (i.e.,%ΔC1) showed a decreasing trend from the southern inflowing river mouths to the downstream northern outlet at Hukou in both the flood and dry seasons, indicating that the bioavailability of the C1 decreased following the migration of CDOM in the lake. In the dry season and flood season, Lake Poyang was the source of DOC with fluxes of 14.0×103 t·mon-1 and 1.4×103 t·mon-1, respectively, whereas CDOM fluxes in corresponding periods were the source and weak sink with corresponding fluxes of 9.3×1010 m3·(m·mon)-1 and 1.1×1010 m3·(m·mon)-1, respectively. Therefore, the lake released substantial organic matter to the downstream receiving waters during the dry season, whereas in the flood season, the higher water level in the Yangtze River resulted in a prolonged water residence time of the lake, and a fraction of CDOM was bio-degraded into inorganic nutrients, favoring the metabolisms and the eutrophication process of the lake ecosystem.

Biodegradable L-lysine-modified amino black phosphorus/poly(l-lactide-coε-caprolactone) nanofibers with enhancements in hydrophilicity, shape recovery and osteodifferentiation properties.

Biodegradable poly-(lactide-coε-caprolactone) (PLCL) scaffolds have opened new perspectives for tissue engineering due to their nontoxic and fascinating functionality. Herein, a black phosphorus-based biodegradable material with a combination of promising enhanced hydrophilicity, shape recovery and osteodifferentiation properties was proposed. First, amino black phosphorous (BP-NH2) was prepared by a simple ball milling method. Then, L-lysine-modified black phosphorous (L-NH-BP) was formed by hydrogen bonding between L-lysine and amino BP and integrated into PLCL to form PLCL/L-NH-BP composite fibers. The scaffolds had excellent shape recovery and shape fixity properties. Moreover, based on gene expression and protein level assessment, the scaffolds could enhance the expression of alkaline phosphatase (ALP) and bone morphogenetic protein 2 (BMP2), simultaneously improving the mineralization ability of bone mesenchymal stem cells. Specifically, this new composite material was experimentally verified to be degradable under mild conditions. This strategy provided new insight into the design of multifunctional materials for diverse applications.

Multifunctional High-Efficiency Additive with Synergistic Anion and Cation Coordination for High-Performance LiNi0.8Co0.1Mn0.1O2 Lithium Metal Batteries.

Safety and high energy density have long restricted the large-scale practical application of lithium metal batteries because of the unbridled growth of lithium dendrites and the rapid deteriorating cycle performance of the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode. Herein, an additive of RbNO3 with multiple functions is proposed for dendrite-free NCM811 lithium metal batteries. Benefiting from the electrostatic shielding effect formed by Rb+ during the Li+ deposition process and the solvation effect of NO3- to regulate lithium deposition, a high Coulombic efficiency of 95.02% (compared with the low Coulombic efficiency of 89.37% in the blank electrolyte) is acquired in Li//Cu cells, and the uniform growth of the lithium metal deposition with a large strawberry-like morphology is achieved. Moreover, when a cathode of NCM811 matches with a lithium metal anode, an extraordinary capacity retention of 93.67% after 200 cycles with a high Coulombic efficiency of 99.7% in the electrolyte with the RbNO3 system (a capacity retention of 80.1% with a Coulombic efficiency of 98.0% for the blank electrolyte) is achieved at 1C. This work provides guidance for the development of high-efficiency additives with dual synergistic regulation effects of anions and cations for lithium metal batteries in the future.

Supramolecular wrapped sandwich like SW-Si3N4 hybrid sheets as advanced filler toward reducing fire risks and enhancing thermal conductivity of thermoplastic polyurethanes.

A sandwich-like melamine/phytic acid/silicon nitride hybrid (SW-Si3N4) sheets were prepared by supramolecular wrapping as the hybrid flame retardants for thermoplastic polyurethane (TPU). The introduction of Si3N4 sheets as a template could not only induce the generation of two-dimensional phytic/melamine (PAMA) capping layers, but also produce the synergistic flame-retardant effect on TPU composites. Cone test showed that heat release rate (HRR), smoke production rate (SPR) and total smoke production (TSP) values of TPU were decreased obviously by adding SW-Si3N4. TG-IR test indicated the dramatic inhibition of aromatic compound, hydrocarbons, CO and HCN release. Besides, the thermal conductivity of composites was obviously improved by adding SW-Si3N4. This work may provide better reference for developing multi-functional TPU composites for diverse application.

[Sources and Optical Dynamics of Chromophoric Dissolved Organic Matter in Different Types of Urban Water Bodies].

In the past few decades, China's rapid industrial activities and urbanization processes have greatly impacted the urban surface water ecosystem. The changes in the quality of urban surface water directly affect the supply and carbon cycling of urban waters. We collected 50 water samples from urban rivers, lakes, and reservoirs in the city of Changchun in June 2020. Three-dimensional fluorescence spectroscopy coupled with parallel factor analysis (EEMs-PARAFAC) was used to unravel the optical characteristics, composition, and sources of chromophoric dissolved organic matter (CDOM). Our results indicated that the mean concentration of DOC is significantly higher in urban rivers than in reservoirs (t-test, P<0.05), and the mean UV absorption coefficient of CDOM a254 of urban rivers is significantly larger than that of park lakes and reservoirs (t-test, P<0.05), indicating that urban rivers have the highest concentration of CDOM. The spectral slope of CDOM absorption S275-295 and the spectral slope ratio SR were shown to be higher in park lakes than in reservoirs, and even higher than in urban rivers (t-test, P<0.001). Three fluorescent components were obtained using PARAFAC, namely terrestrial human-like (C1), microbial human-like (C2) and tryptophan-like (C3) components. The mean fluorescence intensity of C1-C3 was significantly higher in urban rivers than in both the park lakes and reservoirs (t-test, P<0.005), and the mean fluorescence intensity of C1 in the reservoir water body was significantly higher than that of C2 and C3 (t-test, P<0.005), indicating that the discharge of municipal wastewater likely contributes significantly to the CDOM pool of urban rivers in Changchun, and the contribution percentages of highly bio-labile protein-like components to the CDOM pool in these waters are high. Urban wastewater treatment should be strengthened to effectively protect water quality, as well as the economic, environmental, and ecological functions of urban waters in Changchun City.

Flame-Retardant ADP/PEO Solid Polymer Electrolyte for Dendrite-Free and Long-Life Lithium Battery by Generating Al, P-rich SEI Layer.

The poly(ethylene oxide) solid polymer electrolyte (PEO SPE) has recently received much attention, however, the organic components in the SPE are still flammable. In this paper, we find that the high efficiency halogen-free aluminum (Al) diethyl hypophosphite flame retardant (ADP) is effective in reducing the flammability of PEO SPE. The SEI layer containing Al and phosphorus (P) inhibits the growth of lithium dendrite and enhances the cycle life of the battery. The capacity of a LiFePO4/SPE/Li battery containing ADP is still 123.2 mAh g-1 at 1.0 C and the Coulombic efficiency is as high as 99.95% after 1000 cycles (60 °C). At the same time, Al, P-rich SEI can inhibit the growth of lithium dendrite and the cycle stability of the battery is further enhanced.

Polyacrylonitrile@metal organic frameworks composite-derived heteroatoms doped carbon@encapsulated cobalt sulfide as superb sodium ion batteries anode.

Considering the finite resources of nonrenewable fossil fuels and urgent demands of modern society, sodium ion batteries (SIBs) featuring low cost, considerable natural supply and environmental friendless, show huge prospects in energy storage field, especially in constructing massive energy storage networks. Here, we propose a facile polyacrylonitrile@metal organic frameworks composite-derived sulfuration method, for acquiring heteroatoms doped carbon@encapsulated CoS2 nanoparticles (NSPCFS@CoS2) as SIBs anode. This electrode shows long and steady cycling process at 1 A g-1. After running 2095 cycles, it maintains a capacity of 546.3 mA h g-1. An exceedingly low capacity fading ratio of 0.013% per cycle can be acquired. Also, it gives high discharge capacities of 540.7 and 493.6 mA h g-1, even at 4 and 8 A g-1, separately. In addition, NSPCFS@CoS2 possesses a comparative or even better rate capability than other CoS2 based materials and other types of metal sulfides. Overall, this electrode exhibits superior cycling and rate performances. Additionally, its Na+ reaction kinetics and storage mechanism are deeply investigated.

Controllable magnetic field aligned sepiolite nanowires for high ionic conductivity and high safety PEO solid polymer electrolytes.

Poly (ethylene oxide) (PEO) polymer electrolyte, attracts great attention owing to its excellent flexibility, good processability and high safety compared with liquid electrolytes. However, its low ionic conductivity and weak ability to suppress the lithium dendrite severely restrict the further progress of PEO. Herein, we prepare a high ionic conductivity solid polymer electrolyte for all-solid-state lithium batteries by mixing PEO and magnetically aligned functionalized sepiolite (KFSEP) nanowires. The ionic conductivity of PEO/LiTFSI/10%⊥KFSEP solid polymer electrolyte is 2.0 × 10-5 S cm-1 at 20 °C (The ionic conductivity of PEO/LiTFSI solid polymer electrolyte is 4.0 × 10-7 S cm-1 at 20 °C). The experiments and simulation analysis indicate that the aligned nanowires provide a fast-moving channel for lithium ions. The capacity of Li/PEO/LiTFSI/10%⊥KFSEP/LFP cell is 130 mAh g-1 at 1.0 C under 60 °C after 450cycles. Furthermore, Li/PEO/LiTFSI/10%⊥KFSEP/LFP cell shows 150 mAh g-1 at 0.2 C under 25 °C. The Li/PEO/LiTFSI/10%⊥KFSEP/Li cell can work normally more than 600 h, indicating the high stability and lithium dendrite suppressing function of PEO/LiTFSI/10%⊥KFSEP. Overall, a high performance solid polymer electrolyte with higher safety is constructed by incorporating magnetically aligned sepiolite nanowires into PEO.

[Zonation on non-point source pollution risk in the lower reaches of Zijiang River based on the "source-sink" theory]. / 基于"源-汇"理论的资江下游地区非点源污染风险区划.

Non-point source pollution risk assessment and zonation research are of great significance for the eco-environmental protection and optimization of land use structure. We identified the "source" and "sink" landscape using the "source-sink" landscape pattern theory based on the two phases of land use data in the lower reaches of Zijiang River in 2010 and 2018. We comprehensively considered the non-point source pollution occurrence and migration factors, and used location-weighted landscape contrast index (LCI) and non-point source pollution load index (NPPRI) to analyze non-point source pollution risk spatio-temporal characteristics in the study area. Zonation on non-point source pollution in the lower reaches of Zijiang River was studied by identifying the key factors of non-point source pollution risk. The results showed that the overall risk of non-point source pollution was relatively low. The sub-basin with "sink" landscape was the main type, accounting for 61.2%. Non-point source pollution risk was low in the southwest and was high along the banks of Zhixi River, Taohua River and main stream of Zijiang River, as well as plain in the northeast of the lower Zijiang River. The risk of non-point source pollution from 2010 to 2018 showed an increasing trend. The changes in landscape pattern, especially the expansion of rural settlement, arable land and the shrinkage of forest land had positive and negative responses to the risk of non-point source pollution, respectively. LCI, slope, and distance were the key factors affecting the change of the risk index of non-point source pollution. The lower reaches of the Zijiang River could be divided into four control regions: pollution treatment area near river, low slope pollution control area, ecological restoration-risk prevention and control area, and ecological priority protection area.

Anisotropic, low-tortuosity and ultra-thick red P@C-Wood electrodes for sodium-ion batteries.

Red phosphorus (P) is considered to be the most suitable electrode for sodium-ion batteries due to its low cost, earth abundance and high theoretical capacity. Numerous studies have focused on improving the low conductivity and the extremely large volume change of red P during the cycling process. However, these strategies heavily decrease the P mass loading in the electrode. Herein, inspired by natural wood, we successfully develop an ultra-thick bulk red Phosphorus@Carbon-Wood (red P@C-Wood) electrode via the vaporization-condensation process. The sodium-ion batteries assembled with the fabricated red P@C-Wood electrode provide a high areal capacity of 18 mA h cm-2 (≈5 times those of other reported electrodes) and the P mass loading of up to 8.4 mg cm-2 (≥2 times those of other reported electrodes). The combination of red phosphorus and carbonized wood provides a new strategy for people to improve the areal energy density of lithium and sodium batteries.

[Response of Chromophoric Dissolved Organic Matter Dynamics to Different Hydrological Scenarios in the Two Largest Freshwater Lakes Connected to the Yangtze River].

Poyang Lake and Dongting Lake are the two largest freshwater lakes in China connected to the Yangtze River. Changes in the water quality of the two lakes are critical to the water security of the residents surrounding the lakes. Analyses of the optical properties, including chromophoric dissolved organic matter (CDOM) absorption and fluorescence spectroscopy coupled by parallel factor analysis (PARAFAC), were carried out to investigate the dynamics of CDOM in the two lakes in different hydrological scenarios. Our results indicated that different hydrological scenarios have more notable effects on the CDOM dynamics in Poyang Lake compared to those in Dongting Lake. In Poyang Lake, the mean CDOM absorption a(254) and dissolved organic carbon (DOC) were higher in the wet season than in the dry-to-wet transition season, and higher still than in the dry season (t-test, P<0.01), and the mean of the CDOM absorption spectral slope S275-295 was higher in the dry season than in the dry-to-wet transition season and higher still than in the wet season (t-test, P<0.01). In Dongting Lake, the mean of a(254) was not significantly different between different hydrological periods, and SUVA254 reached its maximum in the dry-to-wet transition season. Four fluorescent components were identified using parallel factor analysis. The contribution percentage of CDOM protein-like components in the two lakes was higher during the dry season, and the protein-like components and humic-like components contributed roughly the same amount in the dry-to-wet season, whereas the humic-like components accounted for the main proportion in both lakes during the wet season. From the perspective of spatial distribution, the fluorescence intensity of the four components of Poyang Lake was lower in the southern upstream than in the northern downstream lake regions during the dry season, whereas in the wet season a contrast pattern was found, i.e., with high values found in the upstream lake regions. The spatial difference of fluorescence intensity of the four components in the east of Dongting Lake during the dry season was greater than that in the wet season. We found that DOC increased with increasing water level (r2=0.99, P<0.01) in Poyang Lake and tryptophan-like C2 decreased with increasing water level (r2=0.99, P<0.05) in Dongting Lake. Therefore, the water quality of the two lakes should be managed in a targeted manner according to the response characteristics of CDOM in the two lakes under different hydrological scenarios.