Yellow Region Research Articles

Assessing the impact of shipping emissions on ozone concentrations in East Asia: Insights from KORUS-AQ and SIJAQ 2021 campaign periods

This study analyzed the impact of shipping emissions on ozone (O3) concentrations in East Asia during the Korea-United States Air Quality (KORUS-AQ) and the Satellite Integrated Joint monitoring for Air Quality (SIJAQ) 2021 campaign period. Numerical simulations were performed during the KORUS-AQ (May 2016, the KORUS case) and the SIJAQ 2021 (October–November 2021, the SIJAQ case) using Community Multi-scale Air Quality (CMAQ), the three-dimensional chemical transport model. We additionally simulated an experiment without shipping emissions to compare the impact with and without shipping emissions. Using the validated simulation results, the average O3 concentrations in inland regions were found to be 35.63 ppb and 20.62 ppb in the KORUS and SIJAQ cases, respectively. The average O3 concentrations were higher in the KORUS case owing to the difference in weather conditions between the two cases in various seasons. The results of examining the impact of shipping emissions on O3 concentrations in the ocean area indicate that both the KORUS and SIJAQ cases resulted in a decrease in O3 concentrations in the Yellow Sea region, while the O3 concentrations increased in the East Sea and North Pacific regions. In particular, in the Yellow Sea and East China Sea, where the O3 concentrations decreased in the KORUS case, O3 sensitivity results showed volatile organic compounds (VOC)-sensitive regime when the shipping emissions were removed but changed to nitrogen oxide (NOx)-sensitive regime when the shipping emissions were added. Meanwhile, in the inland regions, the SIJAQ case decreased O3 concentrations in most areas, whereas the KORUS case showed an increase in O3 concentrations in the Korean Peninsula and Japan. Analysis of O3 sensitivity revealed that the regions of the Korean Peninsula and Japan, where O3 concentrations increased, exhibited a NOx-sensitive regime. Particularly, in the case of the Korean Peninsula, the initial transport of shipping emissions in the western part led to a decrease in O3 concentrations. However, as shipping emissions were further transported from west to east, they became more diluted, and additional NOx generated by O3 titration reactions was also transported, gradually increasing O3 concentrations. Furthermore, we found that during seasons with abundant BVOC emissions, the transport of shipping emissions could contribute to additional O3 production. These results confirmed that shipping emissions in East Asia primarily reduce O3 concentrations, however, differences in seasonal and regional O3 sensitivity and transportation patterns can contribute to O3 production.

Stoke's shift and quantum efficiency enhancement in fluorescent coumarin aldehyde (HMCA) dye-conjugated chitosan matrix for optoelectronic applications

A greenish-yellow emissive fluorescent coumarin aldehyde conjugated chitosan matrix was prepared by performing a Schiff base reaction between 7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde (HMCA) and chitosan. The newly formed imine linkage was confirmed by the appearance of an absorption band at 1641 cm−1 in the IR spectrum and also supported by the solid-state 13C-NMR with cross polarisation magic angle spinning (CPMAS) method. The molecular weight of the HMCA-conjugated chitosan matrix was augmented with an increase in the HMCA concentration. The SEM images unveiled crystallite aggregates in the chitosan matrix and the improved crystallinity was witnessed in the PXRD result. The chemically conjugated chitosan film unveiled a larger Stoke's shift value of 183–224 nm which was just 50–130 nm in pure HMCA. The conjugate material could overcome the self-absorption issue associated with the coumarin aldehyde. The coumarin aldehyde exhibited dual emission at 390 nm and 440 nm but it was shifted to 520 nm with single emission upon reaction with chitosan. The observed redshift could be assigned for the formation of static excimer that resulted from the chitosan backbone containing pendant chromophore (coumarin dye) which could interact with another neighbouring chromophoric group of the same chain or different chain creating a ground-state stable dimer. The emission of conjugate material shifted from blue to greenish yellow region with a higher quantum yield of 30.21 % compared to 8.57 % of HMCA alone. The calculated indirect band gap of 2.25–2.34 and the optimum refractive index suggested the potential optoelectronic applications of HMCA-conjugated chitosan as an OLED Material.

Influence of below‐cloud evaporation on stable isotopes of precipitation in the Yellow River source region

AbstractThe study of below‐cloud evaporation effects under clouds in the Yellow River source region is of great significance for regional water resource generation as well as for water resource security in the arid and semi‐arid regions of northern China. In this study, we quantitatively assessed the evapotranspiration effect in the Yellow River source region from March to November based on the improved Stewart model. The study concluded that: (1) below‐cloud evaporation was slightly higher in summer than in other seasons (residual fractions of raindrop evaporation were 80.57% in summer, 81.12% in spring, and 84.2% in autumn, respectively); and (2) sub‐cloud evaporation diminishes with increasing altitude (residual fractions of raindrop evaporation were 83.09% in the western part of the area, 81.82% in the central part of the area, and 81.36% in the eastern part of the area, respectively). (3) The total linear index between study areas f and ∆d is 2.24, where f > 95%, it is 1.19; that is, the evaporation of raindrops increases by 1% and the reduction in the excess of mercury by about 2‰. (4) Local meteorological factors (temperature, precipitation, and relative humidity) and raindrop diameter have a cross‐influence on below‐cloud evaporation, with relative humidity having the most significant effect, with the highest correlation coefficient of 3.03 when relative humidity is less than 70%. The results of the study can provide a parameter basis for hydrological and climatic models in the Yellow River Basin.

Determination of priority conservation areas in the Yellow River source region based on ecosystem integrity evaluations

The conservation of the ecosystem in the Yellow River source region (YRSR) has become a crucial national strategy in China, emphasizing the need for evaluating ecosystem integrity to identify priority conservation areas (PCAs). Current research has primarily employed a limited number of indicators or a single dimension to assess ecosystem integrity, which may overlook comprehensive considerations required for effective conservation planning. To address this, a multidimensional approach was adopted in this study to evaluate ecosystem integrity, incorporating three dimensions: biological diversity, ecosystem function, and stress components. The MaxEnt and Fragstats models were employed to create an ecosystem integrity map and Marxan was used to identify priority conservation areas within the YRSR. Our results showed that (1) the index of ecosystem integrity gradually declined from east to west, consistent with the spatial distribution of biodiversity and ecosystem function, whereas the stress component exhibits a decreasing trend from northeast to southwest. (2) the priority protected areas were distributed in Maduo, Ruoergai, Maqu, Maqin, Henan, Gande, and Jiuzhi Counties. Furthermore, to address existing protection gaps and enhance connectivity, it was recommended to incorporate an additional 27,644 km2 of southwest and central YRSR into the PCAs. Overall, the study offered practical recommendations for the conservation of the ecosystem in the YRSR. In addition, the method of PCAs determination in this study could provide a reference for the government’s growing nature conservation affairs, which will contribute to sustainable development.

Water-salt transport characteristics of saline soil under hydraulic remediation measures in the Yellow River Delta region of China

Water-salt transport characteristics of saline soil under hydraulic remediation measures in the Yellow River Delta region of China

Investigation of the regulatory effects of water and nitrogen supply on nitrogen transport and distribution in wolfberry fields.

Resource-based water shortages, uncoordinated irrigation, and fertilization are prevalent challenges in agricultural production. The scientific selection of appropriate water and fertilizer management methods is important for improving the utilization efficiency of agricultural resources and alleviating agricultural non-point source pollution. This study focused on wolfberry and compared the effects of four irrigation levels [full irrigation (W0, 75%-85% θf), slight water deficit (W1, 65%-75% θf), moderate water deficit (W2, 55%-65% θf), and severe water deficit (W3, 45%-55% θf)] and four nitrogen application levels [no nitrogen application (N0, 0 kg·ha-1), low nitrogen application (N1, 150 kg·ha-1), medium nitrogen application (N2, 300 kg·ha-1), and high nitrogen application (N3, 450 kg·ha-1)] on soil nitrate nitrogen (NO3 --N) transport, plant nitrogen allocation, and soil nitrous oxide (N2O) emissions during the harvest period of wolfberry. And this study used CRITIC-entropy weights-TOPSIS model to evaluate 16 water and nitrogen regulation models comprehensively. The results revealed the following: (1) The NO3 --N content of the soil decreased with increasing horizontal distance from the wolfberry. It initially decreased, then increased, and finally decreased with an increase in soil depth. The average NO3 --N content in the 0-100 cm soil layer ranged from 3.95-13.29 mg·kg-1, indicating that W0 > W1, W2, W3, and N3 > N2 > N1 > N0. (2) The soil NO3 --N accumulation ranged from 64.45-215.27 kg·ha-1 under varying water and nitrogen levels, demonstrating a decreasing trend with increasing horizontal distance. The NO3 --N accumulation at each horizontal distance increased with increasing irrigation and nitrogen application. The NO3 --N accumulation of W0N3 treatment increased by 5.55%-57.60% compared with the other treatments. (3) The total nitrogen content and nitrogen uptake in all wolfberry organs were W1 > W0 > W2 > W3, and N2 > N3 > N1 > N0. The maximum total nitrogen content and nitrogen uptake in W1N2 treatment were 3.25% and 27.82 kg·ha-1 in the roots, 3.30% and 57.19 kg·ha-1 in the stems, 3.91% and 11.88 kg·ha-1 in the leaves, and 2.42% and 63.56 kg·ha-1 in the fruits, respectively. (4) The emission flux and total emission of N2O increased with increasing irrigation and nitrogen application. The emission flux exhibited a transient peak (116.39-177.91 ug·m-2·h-1) after irrigation. The intensity of N2O emissions initially decreased and then increased with an increase in the irrigation amount. It also initially increased with increasing nitrogen application amount, then decreased, and finally increased again. The maximum emission intensity was observed under the W3N3 treatment (0.23 kg·kg-1). The N2O emission coefficients ranged from 0.17%-0.39%, in the order of W0 > W1 > W2 > W3 (except for N1) and N1 > N2 > N3. (5) Under varying water and nitrogen concentrations, N2O emission flux showed a positive linear correlation with soil pore water content and NO3 --N content and a negative linear correlation with soil temperature. The comprehensive evaluation revealed that a slight water deficit (65%-75% θf) combined with medium nitrogen application (300 kg·ha-1) decreased soil NO3 --N leaching, increased nitrogen uptake, and reduced N2O emission. These findings can serve as a reference for improving the efficiency and reducing emissions of wolfberry in the Yellow River irrigation region of Gansu Province and in similar climate zones.

Effect of biochar addition on water–salt distribution and growth of winter wheat in coastal saline‐alkali soils under brackish water irrigation

AbstractTo investigate water‐saving and yield‐enhancing improvement programmes suitable for saline‐alkali soils in the Yellow River Delta region, this study conducted outdoor pot experiments utilizing local moderately saline‐alkali soils as research subjects. The primary focus was to examine the impact of biochar addition on water and salt distribution in saline‐alkali soils and its effect on winter wheat growth under brackish water irrigation conditions. The study design established three different irrigation water mineral concentrations (0, 2 and 4 g L−1) during the research. Two types of biochar, wheat straw biochar (WB) and corn straw biochar (CB), were used with four different applications (0, 5, 10 and 20 t ha−1). There were 21 treatments; each replicated three times. These findings demonstrated that brackish water irrigation and biochar application contributed to a notable increase in soil water content (SWC), with increases ranging from 12.8 to 83.9% across treatments. Using brackish water for irrigation increases soil salt content (SSC) and exacerbates soil salinization. However, the application of biochar counteracts this effect by reducing soil salinity and mitigating the degree of salinization. Treatments applying biochar mostly increased SSC, but proper application had a salinity‐reducing effect, reducing SSC by up to 15.2%. And biochar reduced the soil sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP), mitigating the adverse effects of high salinity on winter wheat. Finally, the application of biochar promoted the growth of winter wheat and increased yield, with the treatment applying 10 t ha−1 of CB (K2Y10) producing the greatest yield under brackish water irrigation conditions and increased by 18% compared with the treatment without biochar (CK0). In summary, considering the aspects of water conservation, salt reduction and yield increase, the most effective saline land improvement programme for this region involved using 2 g L−1 brackish water for irrigation in combination with applying K2Y10. This approach balances addressing soil salinity, enhancing water conservation and maximizing crop yields.

Assessing the ecological impacts of polycyclic aromatic hydrocarbons petroleum pollutants using a network toxicity model

Polycyclic aromatic hydrocarbons (PAHs) are significant petroleum pollutants that have long-term impacts on human health and ecosystems. However, assessing their toxicity presents challenges due to factors such as cost, time, and the need for comprehensive multi-component analysis methods. In this study, we utilized network toxicity models, enrichment analysis, and molecular docking to analyze the toxicity mechanisms of PAHs at different levels: compounds, target genes, pathways, and species. Additionally, we used the maximum acceptable concentration (MAC) value and risk quotient (RQ) as an indicator for the potential ecological risk assessment of PAHs. The results showed that higher molecular weight PAHs had increased lipophilicity and higher toxicity. Benzo[a]pyrene and Fluoranthene were identified as core compounds, which increased the risk of cancer by affecting core target genes such as CCND1 in the human body, thereby influencing signal transduction and the immune system. In terms of biological species, PAHs had a greater toxic impact on aquatic organisms compared to terrestrial organisms. High molecular weight PAHs had lower effective concentrations on biological species, and the ecological risk was higher in the Yellow River Delta region. This research highlights the potential application of network toxicity models in understanding the toxicity mechanisms and species toxicity of PAHs and provides valuable insights for monitoring, prevention, and ecological risk assessment of these pollutants.

Effects of irrigation and nitrogen application on soil water and nitrogen distribution and water-nitrogen utilization of wolfberry in the Yellow River Irrigation Region of Gansu Province, China.

To address the problems of extensive field management, low productivity, and inefficient water and fertilizer utilization in wolfberry (Lycium barbarum L.) production, an appropriate water and nitrogen regulation model was explored to promote the healthy and sustainable development of the wolfberry industry. Based on a field experiment conducted from 2021 to 2022, this study compared and analyzed the effects of four irrigation levels [75%-85% θf (W0, full irrigation), 65%-75% θf (W1, slight water deficit), 55%-65% θf (W2, moderate water deficit), and 45%-55% θf (W3, severe water deficit)] and four nitrogen application levels [0 kg·ha-1 (N0, no nitrogen application), 150 kg·ha-1 (N1, low nitrogen application), 300 kg·ha-1 (N2, medium nitrogen application), and 450 kg·ha-1 (N3, high nitrogen application)] on soil water distribution, soil nitrate nitrogen (NO3 --N) migration, yield, and water-nitrogen use efficiency of wolfberry. The soil moisture content of the 40-80 cm soil layer was higher than those of 0-40cm and 80-120cm soil layer. The average soil moisture content followed the order of W0 > W1 > W2 > W3 and N3 > N2 > N1 > N0. The NO3 --N content in the 0-80 cm soil layer was more sensitive to water and nitrogen regulation, and the cumulative amount of NO3 --N in the soil followed the order of W0 > W1> W2 > W3 and N3 > N2 > N1 > N0 during the vegetative growth period. There was no evidently change in soil NO3 --N accumulation between different treatments during the autumn fruit. The yield of wolfberry under the W1N2 treatment was the highest (2623.09 kg·ha-1), which was 18.04% higher than that under the W0N3 treatment. The average water consumption during each growth period of wolfberry was the highest during the full flowering period, followed by the vegetative growth and full fruit periods, and the lowest during the autumn fruit period. The water use efficiency reached a peak value of 6.83 kg·ha-1·mm-1 under the W1N2 treatment. The nitrogen uptake of fruit and nitrogen fertilizer recovery efficiency of fruit first increased and then decreased with increasing irrigation and nitrogen application. The treatment of W1N2 obtained the highest nitrogen uptake of fruit and nitrogen recovery efficiency of fruit, which were 63.56 kg·ha-1 and 8.17%, respectively. Regression analysis showed that the yield and water-nitrogen use efficiency of wolfberry improved when the irrigation amount ranged from 315.4 to 374.3mm, combined with nitrogen application amounts of 300.0 to 308.3 kg·ha-1. Additionally, the soil NO3 --N residue was reduced, making it an optimal water and nitrogen management model for wolfberry planting. The present findings contribute novel insights into the production of wolfberry with saving water and reducing nitrogen, which helps to improve the level of wolfberry productivity in the Yellow River irrigation region of Gansu Province and other areas with similar climate.

Evaluation of the Effectiveness of Water Ecological Restoration Based on the Relationship between the Supply and Demand of Ecological Products—A Case Study of the Yellow River Delta

The imbalance between the supply and demand of ecological products between society and ecosystems is an important cause of a series of water ecological problems, and water ecological restoration projects aim to improve the above supply–demand relationship by means of inputs from the social side. For this reason, this paper takes the Yellow River Delta region as an example to launch a study on the assessment of the effectiveness of water ecological restoration projects from the perspective of the supply and demand of ecological products. Specifically, the level of the supply and demand of ecological products, as well as the relationship between the supply and the demand in the studied area, were measured using the equivalent factor approach and the water footprint approach, and the effects of the Yellow River Delta hydro-ecological restoration project were assessed by integrating the following four metrics: land use, supply of ecological products (ecosystem services), demand for ecological products, and the relationship between the supply of and demand for ecological products. The results of this study show that although the hydro-ecological restoration project continues to replenish water resources in the Yellow River Delta region, and promotes the level of ecological product supply in the study area through the restoration of wetlands and water, the growing and excessive demand for ecological products in the study area still puts the local ecosystems at risk of degradation. In the future, the Yellow River Delta region should continue to control the scale of land for production and living on the supply side of ecological products and increase its investment in water ecological restoration, while establishing a highly efficient mode of ecological product development and utilization and a reasonable mechanism for the payment of ecological products on the demand side. In addition, the Yellow River Delta region needs to pay attention to the impacts of rising sea levels and other climatic problems on ecological restoration.

Tunable Visible Light and Energy Transfer Mechanism in Tm3+ and Silver Nanoclusters within Co-Doped GeO2-PbO Glasses.

This study introduces a novel method for producing Ag nanoclusters (NCs) within GeO2-PbO glasses doped with Tm3+ ions. Sample preparation involved the melt-quenching method, employing adequate heat treatment to facilitate Ag NC formation. Absorption spectroscopy confirmed trivalent rare-earth ion incorporation. Ag NC identification and the amorphous structure were observed using transmission electron microscopy. A tunable visible emission from blue to the yellow region was observed. The energy transfer mechanism from Ag NCs to Tm3+ ions was demonstrated by enhanced 800 nm emission under 380 and 400 nm excitations, mainly for samples with a higher concentration of Ag NCs; moreover, the long lifetime decrease of Ag NCs at 600 nm (excited at 380 and 400 nm) and the lifetime increase of Tm3+ ions at 800 nm (excitation of 405 nm) corroborated the energy transfer between those species. Therefore, we attribute this energy transfer mechanism to the decay processes from S1→T1 and T1→S0 levels of Ag NCs to the 3H4 level of Tm3+ ions serving as the primary path of energy transfer in this system. GeO2-PbO glasses demonstrated potential as materials to host Ag NCs with applications for photonics as solar cell coatings, wideband light sources, and continuous-wave tunable lasers in the visible spectrum, among others.

Natural and regenerated saltmarshes exhibit different bulk soil and aggregate-associated organic and inorganic carbon contents but similar total carbon contents

Saltmarshes are considered to be one of the planet's most efficient carbon sinks. The continued loss of saltmarshes and induced ecological consequences promoted their restoration worldwide. Previous efforts aimed to evaluate the success of restoration in terms of organic carbon accumulation, but inorganic carbon and carbon contents within soil aggregates, which are essential for making a comprehensive assessment of the carbon sink function, were rarely studied. To fill this gap, a range of metrics including bulk and aggregate-associated soil organic and inorganic carbon contents together with the soil's physical, chemical and microbiological parameters were measured to compare natural and a 15-year restoration effort in saltmarsh habitats within the Yellow River Delta region in eastern China. The results showed that regenerated saltmarsh exhibited significantly higher soil organic carbon (SOC) contents but significantly lower soil inorganic carbon contents, resulting in no notable change in total carbon contents between the regenerated and natural saltmarshes. SOC contents within the silt and clay fractions and their contribution to the bulk SOC contents were significantly lower in the regenerated saltmarsh than those in the natural ones (P < 0.05). In regenerated saltmarsh, significantly lower soil microbial biomass and distinct microbial community composition with reduced Gram-negative to Gram-positive bacteria ratios were observed compared to natural saltmarsh. These findings indicate the stability of SOC fraction and soil microbe-mediated carbon biogeochemical processes differed between naturally occurring and artificially regenerated saltmarshes. As interest in blue carbon programs gains global attention, further research on the generation and transformation processes of different carbon fractions during restoration are needed, which can be conducive to elucidating more details in coastal carbon cycling processes.

Variability in soil nematode communities across recovery patches in degraded Alpine meadows of the Yellow River source region

Summary Accurate measurements of soil nematode communities are important for an in-depth understanding of the ecological functions of soil nematodes. High throughput sequencing (HTS) has been reported extensively, but the concordance between HTS and morphological identification results is still lacking. To compare two methods, we selected bare patches (BP), short-term recovery patches (SP), middle-term recovery patches (MP) and long-term recovery patches (LP) of different restoration succession stages in three sample sites to survey the nematode characteristics. In addition to nematode community structure and community ecological function, common nematode genera in BP, SP, MP and LP were compared by two methods: HTS and morphological identification. The results show that the number of species identified in the morphological analysis was lower than using HTS. The soil nematode diversity in different recovery patches was LP &gt; MP &gt; SP &gt; BP. The indices of Shannon-Wiener, Pielou, Simpson and species number of different recovery patches based on HTS reflected the biodiversity of nematode communities, which was consistent with the results of morphological identification. Of the common nematode genera, Coslenchus, Aphelenchus and Leptonchus showed a significant correlation by the two methods. Although both methods have limitations, the HTS provides a more effective means of observing soil nematode biodiversity levels for rapid insight across recovery patches in degraded alpine meadows of the Yellow River source region in our results.

MgAl2O4:Ho3+ Nanophosphors: Electrochemical Sensor, Photoluminescence and Photocatalytic Applications

Ho3+-doped MgAl2O4 nanophosphors (1-11 mol%) was synthesised via solution combustion method using oxalyl dihydrazide (ODH) as fuel. The findings revealed a range of band gap energies (Eg) between 4.86 and 5.42 eV. It was confirmed that these values correspond extremely well with the experimental data using the DFT approach. The Ho3+ ions in the host undergo f-f transitions that are triggered at 406 nm and as a result, exhibit discrete photoluminescence emission peaks between 406 and 605 nm. Enhanced MgAl2O4 have CIE coordinates from orange-red to yellow region and 97% colour purity. Photocatalytic properties of nanophosphors under UV light led to the discovery that a rapid orange-red dye is activated at 493 nm. Removal of fast orange red (F-OR) dye using the new photocatalysts and MgAl2O4:Ho3+ nanophosphors has been demonstrated. The investigation showed that 89.02% of the dye lost its colour after being exposed to radiation for 120 min. The modified MgAl2O4:Ho3+ carbon paste electrode used in the cyclic voltametric (CV) technique for lead pollution detection. Based on their electrochemical performance, it is concluded that MgAl2O4:Ho3+ nanophosphors are a viable material for lead detecting electrodes.

Investigation of Manganese Oxide (MnO2) Doped in Calcium Sodium Borosilicate Glasses for Photonics Materials Application

In this work, MnO2 doped in calcium sodium borosilicate (CNBS) glasses was investigated. The glass samples doped with MnO2 were synthesized by the melt quenching method. The structural, physical, optical, and photoluminescence properties were examined and discussed. The X-ray diffraction spectra of the CNBS glasses. There are no sharp peaks to be seen, indicating the amorphous nature of the glasses. The optical absorption in the UV–Vis region showed a broad absorption band around 470 nm. The intensity band of absorption spectra increases with increasing of MnO2 concentration. The luminescence spectra were measured and exhibited intense yellow emissions under 417 nm excitation. The results indicate that the glasses may be suitable for the development of optical material application in the yellow region.

Fluorescent and electronic properties of Dysprosium acylpyrazolone complexes along with their synthesis and structural features

Six distorted square antiprismatic eight coordinated Dysprosium acylpyrazolone complexes were synthesized having the compositions [Dy(L1)3(EtOH)(H2O)] (DyL1), [Dy(L2)3(EtOH)(H2O)] (DyL2), [Dy(L3)3(EtOH)(H2O)] (DyL3), [Dy(L4)3(EtOH)(H2O)] (DyL4), [Dy(L5)3(EtOH)(H2O)] (DyL5), and [Dy(L6)3(H2O)(EtOH)] (DyL6). The structure of all six complexes was examined using ESI-mass, FT-IR, UV–Vis, powder XRD, and thermogravimetric methods. According to the single crystal analysis of DyL4A, the complex was found eight coordinated (DyO8) with a distorted square antiprismatic geometry. The comparison of stimulated powder pattern of DyL4A crystal and experimental powder x-ray data helps to confirm the geometry of other complexes. In the solid-state emission spectra, the transition 4F9/2→6H13/2, which is close to the yellow region of the visible spectrum (∼510–530 nm), exhibits hypersensitivity. The variance in intensity between electric-dipole and magnetic-dipole transition suggests a less asymmetric environment. The solvent effect has been thoroughly investigated through a comparative analysis of electronic spectra in different solvents. The intensity of emission spectra, Y/B ratio, and antenna effect energy diagram were examined from solid-state emission spectra.

The Co-Application of PGPR and Biochar Enhances the Production Capacity of Continuous Cropping Peppers in the Karst Yellow Soil Region of Southwest China

In recent years, a significant impediment to the advancement of China’s agricultural sector is the noteworthy challenge posed by diminished crop yields and quality due to ongoing continuous cropping obstacles. Numerous studies have consistently showcased the potential of plant growth-promoting rhizobacteria (PGPR) and biochar in augmenting the alleviation of continuous cropping barriers. Nevertheless, the potential of PGPR and biochar to remediate and improve continuous cropping peppers in the karst yellow soil area remains unclear. A 2-year field experiment was implemented to examine the impact of PGPR and biochar, when applied alone or in combination, on the production potential of continuous cropping peppers. The results revealed that PGPR and biochar significantly elevated the yield of fresh and dry pepper compared with TF treatment. The utilization of PGPR and biochar resulted in an augmentation of free amino acids, soluble sugar, and vitamin C content in pepper fruits, but a reduction in the nitrate content, which proved advantageous in enhancing the overall quality of peppers. Furthermore, the use of PGPR and biochar demonstrated significant benefits in enhancing NPK accumulation, fertilizer utilization, and economic efficiency. Nevertheless, the co-application of PGPR and biochar yielded significantly better results compared to their individual application. In conclusion, the utilization of PGPR and biochar demonstrated a favorable impact on the productivity and economic benefits of continuous cropping peppers. The simultaneous application of PGPR and biochar represents a promising approach to enhancing yield and improving the quality of peppers in the karst yellow soil region of Southwest China.

Improvement in spectroscopic properties of Dy3+ doped Ba2Mg(PO4)2 phosphors through substitution strategy

In this work, we have synthesized Dy3+ activated Ba2Mg(PO4)2 phosphors by cationic/anionic substitution strategy. We have substituted Ca, Sr and VO4 in Ba2Mg(PO4)2 host lattice. These phosphors were synthesized by a high-temperature solid-state reaction method at 700 °C. The prepared samples' phase formation, thermal stability, photoluminescence properties and CIE coordinate were discovered in detail. The phase purity, morphology, functional groups and thermal stability of the prepared materials were investigated using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Fourier transform infrared (FT-IR) and Thermogravimetric – differential thermal analysis (TG-DTA) techniques. The Photoluminescence (PL) properties of Ba2Mg1−x(PO4)2:xDy3+, Ba2Mg1−x-ySry(PO4)2:xDy3+, Ba2Mg1−x-yCay(PO4)2:xDy3+ and Ba2Mg(1−x)(PO4)2−z(VO4)z:xDy3+ phosphors were studied in detailed. Under the different excitation wavelengths, the PL emission spectra show two characteristic peaks in the blue and yellow regions. In this study, the effect of cationic/anionic substitution has also been investigated. By co-doping (Sr2+, Ca2+, VO43-) ions, it was observed that the PL emission intensity increased significantly. The Commission Internationale de l′Elcairage (CIE) coordinates and color correlated temperature (CCT) of prepared samples were also calculated using ORSRAM SYLVANIA color calculator. The observed results revealed that Dy3+ activated Ba2Mg(PO4)2 phosphor and Sr2+, Ca2+, VO43- co-doped samples have potential applicability for detailed future studies in the field of lighting and display devices.

The Surface Modification Strategy Toward Long Wavelength Emission of Carbon Dots

Carbon dots (CDs), as an important carbon-based nanomaterial, have been widely used in fluorescence (FL) detection, bioimaging, photocatalysis, light-emitting devices (LEDs) and many other fields, owing to their excellent optical properties. Regulating the fluorescent properties of carbon dots (CDs) in a controlled manner has been a fundamental research goal. Herein, solvent-dependent CDs (N-CDs) are synthesized through the solvothermal reaction of [Formula: see text]-phenylenediamine (OPD) in ethanol. When N-CDs are dispersed in solvents of different polarities, the emission wavelength only turned 39[Formula: see text]nm red-shift. While, the O-CDs are obtained by modifying the surface of N-CDs with 1,2,4-benzenetricarboxylic acid (TMA). O-CDs show four obvious FL emission peaks in the yellow, orange and red regions at 554[Formula: see text]nm, 604[Formula: see text]nm, 650[Formula: see text]nm and 712[Formula: see text]nm with a tail extending to 750[Formula: see text]nm, even entering into near-infrared-I (NIR-I) region. Thus, according to the special structure of CDs, this work provides a novel donor-[Formula: see text]-acceptor (D-[Formula: see text]-A) strategy for preparing long wavelength emissive CDs. Finally, the N-CDs and O-CDs are successfully applied to cellular imaging.

Importance of habitat heterogeneity in tidal flats to the conservation of migratory shorebirds.

Understanding species distribution patterns and what determines them is critical for effective conservation planning and management. In the case of shorebirds migrating along the East Asian-Australasian Flyway (EAAF), the loss of stopover habitat in the Yellow Sea region is thought to be the primary reason for the precipitous population declines. However, the rates of decline vary considerably among species, and it remains unclear how such differences could arise within a group of closely related species using apparently similar habitats at the same locales. We mapped the spatial distributions of foraging shorebirds, as well as biotic (benthic invertebrates consumed by migrating shorebirds) and abiotic (sediment characteristics) environmental factors, at a key stopover site in eastern China. Five of the six sediment characteristics showed significant spatial variation with respect to distance along the shoreline or distance from the seawall in the same tidal flat. The biomasses of four of the six most abundant benthic invertebrates were concentrated in the upper or middle zones of the tidal flat. The distribution patterns of all three focal shorebird species on the tidal flat were best explained jointly by this heterogeneity of sediment characteristics and invertebrate prey. These results suggest that the loss of tidal flats along the Yellow Sea, which is typically concentrated at the upper and middle zones, may not only reduce the overall amount of staging habitat, but also disproportionately affect the most resource-rich portions for the birds. Effective conservation of shorebird staging areas along the EAAF and likely elsewhere must consider the subtle habitat heterogeneity that characterizes these tidal flats, prioritizing the protection of those portions richest in food resources, most frequently used by focal bird species, and most vulnerable to anthropogenic threats. Article impact statement: Heterogeneity of tidal flats with respect to biotic and abiotic factors must be considered in shorebird conservation planning.