Search Results (1,609)

Epoxy resin (EP) is an outstanding polymer material known for its low cost, ease of preparation, excellent electrical insulation properties, mechanical strength, and chemical stability. It is widely used in high- and ultra-high-voltage power transmission and transformation equipment. However, as voltage levels continue to increase, EP materials are gradually failing to meet the performance demands of operational environments. Thus, the development of high-performance epoxy resin materials has become crucial. In this study, a combined treatment using plasma and a fluorine-containing coupling agent was employed to fluorinate graphene nanosheets (GNSs), resulting in DFGNSs. Different concentrations of GNSs/DFGNS-modified EP composites were prepared, and their effects on enhancing the surface insulation properties were studied. Tests on surface flashover voltage, surface charge dissipation, trap distribution, and surface resistivity demonstrated that both GNSs and DFGNSs significantly improve the insulation properties of EP materials. Optimal improvement was achieved with a DFGNS content of 0.2 wt%, where the flashover voltage increased by 16.23%. Full article

A Sn58Bi composite solder reinforced by Ni nanoparticles was prepared using a mechanical mixing technique, and the thermomigration microstructure and properties of the solder joints were studied. The findings indicate that incorporating an appropriate quantity of Ni nanoparticles can enhance the microstructure of the composite solder and mitigate the coarsening of Bi-phase segregation. At 0.75 weight percent Ni nanoparticle content, the composite solder’s tensile strength is 59.7 MPa and its elongation is 54.6%, both of which are noticeably greater than those of the base solder. When the thermal loading time is 576 h, the shear strength of the composite solder joint is 25.5 MPa, which is 30.1% higher than that of the base solder joint. This study reveals that the shear fracture path shifts from the boundary region between the solder seam and the IMC layer to the IMC layer itself. Concurrently, the fracture mode evolves from a mix of brittle–ductile fracture, characterized by quasi-cleavage, to a predominantly brittle fracture, marked by numerous “rock candy-like” cross-sectional features and secondary cracking. Adding Ni nanoparticles to the Sn58Bi composite solder/Cu solder junction can significantly extend its service life. Full article

A series of colorful binuclear Schiff bases derived from the different diamine bridges including 1,2- ethylenediamine (bis-Et-SA, bis-Et-4-NEt₂, bis-Et-5-NO₂, bis-Et-Naph), 1,2-phenylenediamine (bis-Ph-SA, bis-Ph-4-NEt₂, bis-Ph-5-NO₂, bis-Ph-Naph), dicyano-1,2-ethenediamine (bis-CN-SA, bis-CN-4-NEt₂, bis-CN-5-NO₂, bis-CN-Naph) have been designed and prepared. The optical properties of these binuclear Schiff base ligands were fully determined by UV–Vis absorption spectroscopy, fluorescence emission spectroscopy, and time-dependent-density functional theory (TD-DFT) calculations. The inclusion of D-A systems and/or π-extended systems in these binuclear Schiff base ligands not only enables adjustable RGB light absorption and emission spectra (300~700 nm) but also yields high fluorescence quantum efficiencies of up to 0.84 in MeCN solution. Then, with the ESIPT (excited-state intramolecular proton transfer) property, fluorescence analysis showed that the probe bis-Et-SA and bis-Ph-SA could recognize Zn²⁺ via the “turn on” mode in the MeCN solution. During the detection process, bis-Et-SA and bis-Ph-SA demonstrate rapid response and high selectivity upon the addition of Zn²⁺. The coordination of Zn²⁺ with the oxygen atom and Schiff base nitrogen atom in a tetrahedral geometry is confirmed by Job’s plot, FT-IR, and ¹H NMR spectroscopy. In addition, the paper test and Hela cells were successfully carried out to detect Zn²⁺. Moreover, the sensitivity of bis-Et-SA and bis-Ph-SA is much better than that of those Schiff base ligands containing only one chelating unit [O^N^N^O]. Full article

New-quality productivity (NQP) serves as a critical indicator for measuring the level of high-quality economic development. Gaining insights into the spatial and temporal patterns along with the key drivers of NQP is essential for promoting the global industrial transformation and revitalizing old cities. This study utilized spatial analysis, Dagum Gini coefficient, Markov chains, and optimal parameter geographical detectors to analyze spatial patterns and influencing factors of NQP across 271 Chinese prefecture-level cities from 2011 to 2021. Findings reveal that the average index of NQP increased from 0.045 in 2011 to 0.072 in 2021, with spatial patterns showing higher levels in coastal regions compared to inland areas. The overall disparity of NQP has diminished, although significant internal imbalances persist, particularly in the eastern region, where the pronounced gap between eastern and central areas remains the primary source of variation. Local NQP development is strongly influenced by proximity to adjacent areas, characterized by path dependence and club convergence effects. Additionally, cultural foundation, urbanization, and economic development play pivotal roles in fostering NQP, with their interactions exhibiting notable nonlinear and dual-factor enhancement effects. These findings provide valuable theoretical and practical insights for advancing NQP levels in China and globally. Full article

The ScanSAR mode image obtained by the Gaofen-3 (GF-3) satellite has an imaging width of up to 130–500 km, which is of great significance in monitoring oceanography, meteorology, water conservancy, and transportation. To address the issues of subswath misalignment and the inability to correct in the processing of GF-3 ScanSAR images in coastal areas using software such as PIE, ENVI, and SNAP, a method for mosaicking and correcting GF-3 ScanSAR images with subswaths that overlap within specified range constraints is proposed. This method involves correlating the coefficients of each subswath thumbnail image in order to determine the extent of the overlap range. Given that the matching points are constrained to the overlap between subswaths, the normalized cross-correlation (NCC) matching algorithm is utilized to calculate the matching points between subswaths. Subsequently, the random sampling consistency (RANSAC) algorithm is employed to eliminate the mismatching points. Subsequently, the subswaths should be mosaicked together with the stitching translation of subswaths, based on the coordinates of the matching points. The image brightness correction coefficient is calculated based on the average grayscale value of pixels in the overlapping region. This is performed in order to correct the grayscale values of adjacent subswaths and thereby reducing the brightness difference at the junction of subswaths. The entire ScanSAR slant range image is produced. By employing the Range–Doppler model for indirect orthorectification, corrected images with geographic information are generated. The experiment utilized three coastal GF-3 ScanSAR images for mosaicking and correction, and the results were contrasted with those attained through PIE software V7.0 processing. This was conducted to substantiate the efficacy and precision of the methodology for mosaicking and correcting coastal GF-3 ScanSAR images. Full article

With the rapid development of industry and agriculture, soil contamination has become a significant environmental issue, and the heavy metal contamination of soils is an important part of it. The main methods for the remediation of heavy metal-contaminated soils include physical methods, chemical methods, biological methods, and combined remediation methods have been proposed as research deepens. However, the standards and evaluation methods for the remediation of heavy metal-contaminated soils are still not well-established. This article discusses the sources and contamination status of heavy metals in soils, the advantages and disadvantages of remediation technology for heavy metal-contaminated soils, remediation standards, and post-remediation evaluation methods. It also proposes scientific issues to be addressed in future research and provides an outlook on future development, hoping to assist in subsequent remediation studies of heavy metal-contaminated soils. Full article

Data interpolation methods are important statistical analysis tools that can fill in data gaps and missing areas by predicting and estimating unknown data points, thereby improving the accuracy and credibility of data analysis and research. Different interpolation methods are widely used in related fields, but the error between different interpolation methods and their interpolation fusion optimization have a significant impact on the interpolation accuracy, which still deserves further exploration. This study is based on two different types of point data: PM_2.5 (PM_2.5 refers to particulate matter in the atmosphere with a diameter of 2.5 μm or less, also known as inhalable particles or fine particulate matter) in Xinyang City, Henan Province, and the elevation of typical gullies in Yuanmou County, Yunnan Province. Using relative difference coefficients and hotspot analysis methods, the differences in error characteristics among four interpolation methods, ordinary kriging (OK), universal kriging (UK), inverse distance weighted (IDW), and radial basis functions (RBFs), were compared, and the influence of interpolation fusion methods on the accuracy of interpolation results was explored. The results show that after interpolation of PM_2.5 concentration and gully elevation, the error difference between OK and UK is the smallest in both datasets. For PM_2.5 concentration data, IDW and UK interpolation errors have the largest difference; for elevation data, the differences between RBF and UK interpolation are the largest. The weighted fusion results show that the interpolation error accuracy of PM_2.5 concentration data with an interpolation point density of 0.009 points per square kilometer is improved, and the root mean square error (RMSE) after fusion is reduced from 0.374 μg/m³ to 0.004 μg/m³. However, the error accuracy of the elevation data of the gully with an interpolation point density of 0.76 points/m² did not improve significantly. This indicates that characteristics such as the density of the original data are important factors that affect the accuracy of interpolation. In the case of sparse interpolation points, it is possible to consider fusing the interpolation results with different error patterns to improve their accuracy. This study provides a new idea for improving the accuracy of interpolation errors. Full article

In the context of water scarcity, understanding the mechanisms influencing and altering agricultural water consumption can offer valuable insights into the scientific management of limited water resources. Using Henan Province as a case study, this research applies the Mann–Kendall test method, the spatial Markov transfer chain model, the optimal parameter geo-detector model, and the Logarithmic Mean Divisia Index (LMDI) decomposition method to investigate the evolution characteristics of agricultural water consumption in Henan Province and its key influencing factors. The findings revealed the following: (1) Agricultural water consumption has shown a significant decline from 1999 to 2022. (2) According to observations, the stability of agricultural water consumption exceeds the spillover effect, and cross-border grade transfer is challenging. Moreover, this phenomenon is influenced by the neighboring regions. (3) The key influencing factors of added agricultural value are the sown area of food crops, total sown area, irrigated area, and average annual air temperature. (4) Among the decomposition effects on agricultural water consumption, the contribution of each decomposition effect to changes in agricultural water consumption and the role of spatial distribution exhibit notable differences. Overall, these findings provide theoretical references for the efficient use of agricultural water resources and sustainable development in the region. Full article

Farmland ammonia (NH₃) volatilization is an important source of NH₃, and the application of chemical fertilizer nitrogen (N) is the main factor affecting NH₃ volatilization. The optimal substitution of chemical fertilizer with organic manure and straw reportedly reduces NH₃ volatilization, while reducing irrigation increases NH₃ volatilization. However, the combined effect of nitrogen fertilizer substitution and reducing irrigation on NH₃ volatilization and the role of microorganisms in this process remains unclear. In a soil column experiment, NH₃ volatilization and microbial composition were measured under both multiple N sources and different irrigation levels by the vented-chamber method and metagenomic sequencing. The results revealed that multiple N sources application reduced cumulative NH₃ volatilization by 16.5–75.4% compared to single chemical fertilizer application, and the decreasing trend of NH₃ volatilization under reduced irrigation conditions was greater. Microorganisms had a more important effect on NH₃ volatilization of reduced irrigation than conventional irrigation. The abundance of nirA, arcC, E3.5.1.49, and E3.5.5.1 (ammonia-producing) genes varied significantly at the two irrigation levels. Overall, multiple N sources could inhibit NH₃ volatilization increasing under reducing irrigation compared to a single chemical fertilizer. Our findings contribute valuable insights into the combined effect of reduced irrigation and multiple N sources on NH₃ volatilization. Full article

Water is a crucial and fundamental resource. It is well known that agricultural cultivation, industrial production, and human daily life are not possible without water. Efficiently utilizing water resources is of great significance for achieving global Sustainable Development Goals (SDGs). In order to improve water use efficiency in various industries and promote water-saving development, China has been implementing water-saving society construction since 2002. Henan Province is the main grain-producing area in China, with wheat production accounting for a quarter of the country’s total. As the core area of “Central Plains Agricultural Valley” in Henan Province, Xinxiang City plays an important role in agricultural technology innovation and agricultural production. However, Xinxiang City is facing problems of water scarcity and pollution, which constrain the sustainability of agricultural production. Therefore, building a water-saving society can solve the current water problems faced by Xinxiang City and ensure the sustainable development of the economy and society. This study built an evaluation index system for water-saving society construction in Xinxiang, Henan Province, China. The proposed evaluation index system includes 20 evaluation indices from six aspects—integrated, agricultural water, industrial water, domestic water, water ecology and environment, and water-saving management—and then divides its development level into several stages. The Analytical Hierarchy Process (AHP) was adopted to calculate the index weight. Then, a comprehensive evaluation model for water-saving society construction in Xinxiang City was established by combining it with grey relative analysis (GRA). The results showed that the overall level of water-saving society construction in Xinxiang City is in the excellent stage, whereas water consumption per CNY 10,000 of GDP, the effective utilization coefficient of irrigation water, the reuse rate of industrial water, and the leakage rate of urban water supply network are all in the good stage. However, the urban recycled water utilization rate is still in the poor stage. These research results can effectively and reasonably reflect the development level of water-saving society construction in Xinxiang City and guide the continued implementation of water-saving society construction. At the same time, the comprehensive evaluation of water-saving society construction helps to formulate and adjust water resource management policies and measures; it also holds significant value for sustainable water management and combating water scarcity. Full article

The large-scale vein-type Zn-Pb-Ag deposit in the Eastern Qinling Orogen (EQO) has sparked a long-standing debate over whether magmatism or metamorphism was the primary control or factor in its formation. Among the region’s vein-type deposits, the large-sized Bailugou deposit offers a unique opportunity to study this style of mineralization. Similar to other deposits in the area, the vein-type orebodies of the Bailugou deposit are hosted in dolomitic marbles (carbonate–shale–chert association, CSC) of the Mesoproterozoic Guandaokou Group. Faults control the distribution of the Bailugou deposit but do not show apparent spatial links to the regional Yanshanian granitic porphyry. This study conducted comprehensive H–O–C–S–Pb isotopic analyses to constrain the sources of the ore-forming metals and metal endowments of the Bailugou deposit. The δ³⁴S_CDT values of sulfides range from 1.1‰ to 9.1‰ with an average of 4.0‰, indicating that the sulfur generated from homogenization during the high-temperature source acted on host sediments. The Pb isotopic compositions obtained from 31 sulfide samples reveal that the lead originated from the host sediments rather than from the Mesozoic granitic intrusions. The results indicate that the metals for the Bailugou deposit were jointly sourced from host sediments of the Mid-Late Proterozoic Meiyaogou Fm. and the Nannihu Fm. of the Luanchuan Group and Guandaokou Group, as well as lower crust and mantle materials. The isotopic composition of carbon, hydrogen, and oxygen collectively indicate that the metallogenic constituents of the Bailugou deposit were contributed by ore-bearing surrounding rocks, lower crust, and mantle materials. In summary, the study presents a composite geologic-metallogenic model suggesting that the Bailugou mineral system, along with other lead-zinc-silver deposits, porphyry-skarn molybdenum-tungsten deposits, and the small granitic intrusions in the Luanchuan area, are all products of contemporaneous hydrothermal diagenetic mineralization. This mineralization event transpired during a continental collision regime between the Yangtze and the North China Block (including syn- to post-collisional settings), particularly during the transition from collisional compression to extension around 140 Ma. The Bailugou lead-zinc-silver mineralization resembles an orogenic-type deposit formed by metamorphic fluid during the Yanshanian Orogeny. Full article

As economic development and urbanization continue to accelerate, the Yellow River Basin experiences increasing challenges in balancing land use with ecological environmental protection. Understanding their interactions is crucial for sustainable regional development. This study adopts an integrated evaluation system and a coupling model to examine the dynamic interactions between land use functions and ecological quality in the Yellow River Basin section of Henan Province, China, from 2000 to 2020. The primary findings are as follows: (1) Land use functions improved from 0.276 to 0.303, with high-land-use-function areas expanding eastward. (2) Ecological quality initially declined but subsequently improved, with areas having good and excellent ecological quality increasing from 44.47% to 72.61%. (3) Coupling coherence stabilized, with moderate coordination covering 69.80% of the area by 2020. (4) The fractional vegetation cover and leaf area index were identified as critical influencing factors. Overall, these results highlight the importance of balanced land use planning and targeted ecological conservation strategies. This study provides valuable insights for policymakers aiming to enhance sustainable regional development, emphasizing the importance of integrating ecological security with economic growth in rapidly urbanizing areas. Full article

Nanomaterials have attracted significant attention as signal reporters for immunoassays. They can directly generate detectable signals or release a large number of signaling elements for readout. Among various nanolabels, nanomaterials composed of multiple signaling molecules have shown great potential in immunoassays. Generally, signaling molecules can be entrapped in nanocontainers or self-assemble into nanostructures for signal amplification. In this review, we summarize the advances of signaling molecules-entrapped or assembled nanomaterials for colorimetric and fluorescence immunoassays. The nanocontainers cover liposomes, polymers, mesoporous silica, metal–organic frameworks (MOFs), various nanosheets, nanoflowers or nanocages, etc. Signaling molecules mainly refer to visible and/or fluorescent organic dyes. The design and application of immunoassays are emphasized from the perspective of nanocontainers, analytes, and analytical performances. In addition, the future challenges and research trends for the preparation of signaling molecules-entrapped or assembled nanolabels are briefly discussed. Full article

Amid persistent global food security challenges, the efficient utilization of cultivated land resources has become increasingly critical, as optimizing Cultivated Land Utilization Efficiency (CLUE) is paramount to ensuring food supply. This study introduced a cultivated land utilization index (CLUI) based on Fractional Vegetation Cover (FVC) to assess the spatiotemporal variations in Henan Province’s CLUE. The Theil–Sen slope and the Mann–Kendall test were used to analyze the spatiotemporal variations of CLUE in Henan Province from 2000 to 2020. Additionally, we used a genetic algorithm optimized Artificial Neural Network (ANN) and a particle swarm optimization-based Random Forest (RF) model to assess the comprehensive in-fluence between topography, climate, and human activities on CLUE, in which incorporating Shapley Additive Explanations (SHAP) values. The results reveal the following: (1) From 2000 to 2020, the CLUE in Henan province showed an overall upward trend, with strong spatial heterogeneity across various regions: the central and eastern areas generally showed decline, the northern region remained stable with slight increases, the western region saw significant growth, while the southern area exhibited complex fluctuations. (2) Natural and economic factors had notable impacts on CLUE in Henan province. Among these factors, population and economic factors played a dominant role, whereas average temperature exerted an inhibitory effect on CLUE in most parts of the province. (3) The influenced factors on CLUE varied spatially, with human activity impacts being more concentrated, while topographical and climatic influences were relatively dispersed. These findings provide a scientific basis for land management and agricultural policy formulation in major grain-producing areas, offering valuable insights into enhancing regional CLUE and promoting sustainable agricultural development. Full article

Watershed ecological compensation (WEC) mechanisms can help coordinate the distribution of revenue among different regions and realize the collaborative treatment of water pollution. However, limited research has examined the influence of population flow on the design of ecological compensation mechanisms. In this paper, the differential game method is used to construct a model of water pollution control in upstream and downstream regions with the consideration of population flow. The Lower Yellow River Basin (LYRB), which includes Henan and Shandong Provinces, is taken as a case study, and relevant data are used for simulation analysis. The constraints and population flow factors that influence the establishment of a WEC mechanism between upstream and downstream governments are explored. The results show that (1) the implementation of WEC can stimulate the upstream government’s efforts to treat pollutants, and the amount of pollutants eliminated and the revenue of the upstream and downstream governments increase; (2) with the continuous flow of population from the upstream region to the downstream region, the amount of pollutants eliminated and the revenue of the downstream government decrease; and (3) in the absence of external incentive measures, when the population flow exceeds a certain threshold, the WEC mechanism of the upstream and downstream governments cannot be spontaneously carried out. The conclusions of this study can provide scientific guidance for improving the WEC mechanism between the upstream and downstream governments within a basin. Full article