Amid growing concerns about urban water pollution and intense human disturbances, urban wetlands face severe ecological pressures. However, existing wetland health assessment studies have predominantly focused on large-scale watersheds, lakes, or coastal zones, with insufficient attention to urban wetland ecosystems. Traditional evaluation models also suffer from drawbacks such as subjective weighting biases and difficulties in processing high-dimensional indicator data, and few studies have systematically quantified the relative importance of key factors in urban wetland health. To address these gaps, this study targeted Chengdu’s Baihetan Urban Wetland Park, establishing a practical ecological health assessment system based on the Driving-Force-Pressure-State-Response (DPSIR) framework and innovatively adopting the Simulated Annealing-Projection Pursuit (SA-PP) coupled model to objectively process high-dimensional data, eliminating subjective judgment biases. Assessment of 2018–2021 monitoring data revealed that Baihetan Wetland Park generally maintained a relatively healthy ecological state, with a steady upward trend in health levels over the four-year period. Weight calculation results based on the optimal projection direction vector of the SA-PP model indicated that ecosystem biological characteristic indicators had the most significant impact on overall wetland health, followed by resource and environmental pressure indicators. This study’s novelty lies in integrating the DPSIR framework with the SA-PP model for urban wetland-specific assessment, filling the methodological gap in urban wetland health evaluation under intense human disturbance. Beyond providing a scientific basis for the targeted management of Baihetan Wetland Park, the findings offer a transferable tool for other urban wetlands and broader insights for coordinating urbanization and ecological protection.

Carbon dots (CDs) have emerged as versatile fluorescent nanomaterials for diverse applications. The synthesis of CDs from natural products offers a sustainable alternative to chemical methods. This study presents the preparation of green fluorescent CDs (G-CDs) using seafood mushrooms as the carbon source and 5-amino-2-methylphenol as the nitrogen source through a hydrothermal approach. The G-CDs exhibit maximum excitation/emission peaks at 467/519 nm and a high quantum yield of up to 17.2% in ethanol. Additionally, the G-CDs demonstrate excellent photostability, salt tolerance, and chemical stability. The excitation-independent emissions suggest the presence of unique surface-state luminescent centers. The application of the G-CDs as an anti-counterfeiting fluorescent ink is demonstrated. This work highlights the promise of converting natural food sources into high-performance CDs, expanding their utility across various domains including biomedicine, sensing, and security. Green fluorescent carbon dots (G-CDs) are prepared using seafood mushrooms as carbon source and 5-amino-2-methylphenol as nitrogen source via hydrothermal method. The G-CDs emit excitation-independent light, indicating unique surface-state luminescent centers. This work offers potential for converting natural food sources into high-performance CDs for biomedicine, sensing, and security.image

Consider the whole life cycle process of agricultural green production, a comprehensive evaluation index system of agricultural green development level is constructed by integrating the agricultural cycle development process from input, production to output. It consists 3 subsystems (green input, green production and green product) and 19 indicators. Simulated annealing algorithm was used for projection pursuit optimization. The comprehensive evaluation index system and simulated annealing-projection pursuit model are applied to the comprehensive evaluation of agricultural green development level in 31 provinces of China from 2013 to 2020, and the differences between the eastern, central and western regions are analyzed. The results suggest that: (1) The green production subsystem accounts for the largest proportion in the evaluation index system. (2) From 2013 to 2020, the agricultural greening level in China develops rapidly. In 2013, only Heilongjiang, Jiangsu and Shandong provinces reached a high level of agricultural greening. However, in 2020, there are 14 provinces at the high level of agricultural greening. (3) From 2013 to 2020, there were significant differences between eastern, central and western China, and the differences are still increasing. The order of the green development capacities of agriculture are central > eastern > western, indicating that China's agricultural green development is unbalanced. This study provides scientific decision-making basis for comprehensive evaluation and analysis of agricultural green development level and green agriculture development in China.

Carbon dots (CDs) have emerged as a novel class of fluorescent nanomaterials with superior optical properties and biocompatibility compared to traditional quantum dots. This study demonstrates a facile approach for synthesizing high quantum yield tricolor CDs from the natural precursor dandelion via a one-step solvothermal treatment. Chromatographic separation successfully yielded blue, green, and orange emissive CDs with emission peaks at 481 nm, 530 nm, and 587 nm respectively. Structural and optical characterization revealed the CDs possess excellent photostability, salt resistance, and thermal stability, alongside high quantum yields, measured at 43.8%, 32.9%, and 48.1% for B-CDs, G-CDs, and O-CDs, respectively. Taking advantage of the unique properties of the tricolor CDs, their application in analytical sensing was explored using metal ion detection. The CDs displayed selective quenching responses towards Fe3+, Pb2+, and Sn4+ respectively, with strong anti-interference capabilities. This work provides a sustainable and efficient strategy for producing high-performance multicolor CDs, holding significant implications for reducing the synthesis cost of carbon dots and expanding their application spectrum.

Green-emitting carbon dots (G-CDs) with high quantum yield were successfully synthesized through a one-step bottom-up approach, utilizing laurel leaves as the carbon precursor, o-phenylenediamine (OPD) as the nitrogen source, and N,N-dimethylacetamide (DMAC) as the solvent. Structural characterizations unveiled the presence of abundant nitrogen-containing functional groups on the surface of G-CDs, significantly influencing their luminescent properties. The excitation and emission wavelengths of G-CDs were determined to be 467 nm and 508 nm, respectively, with a quantum yield of up to 49.9 %. Moreover, the emissions of G-CDs were found to be dependent on the excitation wavelength, suggesting a potential correlation between luminescence and particle size. Notably, the stability assessment demonstrated excellent salt resistance and strong photostability of the G-CDs. A brief discussion on the practical application of G-CDs in anti-counterfeit fluorescent ink highlighted their potential in this filed. This study presents a green synthesis strategy for producing high-performance carbon dots, reducing reliance on chemical reagents, lowering synthesis costs, and mitigating environmental pollution.

Multicolor fluorescent carbon dots (CDs) have wide application prospects in many fields. Presented herein reported a synthesis of multicolor fluorescent CDs using zanthoxylum bungeanum as a carbon precursor. By changing the nitrogen sources, blue, green, and red fluorescent carbon dots (B-CDs, G-CDs, and R-CDs) with stable optical properties and high quantum yields (QY) were synthesized. Their emission wavelengths are 492 nm, 523 nm, and 601 nm respectively and their QYs were measured to be 13.1%, 11.2%, and 9.8%, respectively. These CDs exhibit good salt resistance, photobleaching resistance, and chemical stability. These characteristics make them suitable for various applications, particularly in the field of anti-counterfeiting fluorescent ink. This study provides an economic and efficient strategy for synthesizing multicolor fluorescent CDs derived from natural products, highlighting the potential for producing multicolor CDs and enhancing their application value.

Agricultural non-point source pollution (ANPSP) caused a contradiction between economic growth and water environmental security protection. In order to understand the trade-off between social-economic development and water environmental security in the context of agricultural non-point source pollution, a Driving force-Agricultural non-point source pollution-Pressure-State-Response (DAPSR) model framework was proposed, and 23 indicators were selected to construct the evaluation system of water environment security in this study. And we take Ya’an City, China as case study from 2017 to 2019, the characteristics of water pollution was analyzed, and the water environment security was evaluated by method of particle swarm projection pursuit. The results show that: (1) Agricultural non-point source pollutant discharge in Ya’an generally shows a decreasing trend. (2) The agricultural non-point source pollution subsystem and the response subsystem have a great impact on water environment security. (3) According to the values of water environment security, Yucheng, Hanyuan, Tianquan and Lushan are basically safe in level III, Mingshan is unsafe in level IV, Yingjing is safe in level II, Shimian and Baoxing are safe in level II. (4) The degree of agricultural non-point sources is highly correlated with the water environment security. This study shows that the DAPSR model is feasible and practical, and can provide a scientific basis for the decision-making of regional agricultural non-point source pollution prevention and water environmental security protection.

In order to gain an in-depth understanding of the change of urban water environment carrying capacity (WECC), we proposed a framework system of VPOSR (vigor, pressure, organization, state and resilience subsystem), which was used to construct an evaluation index system for urban WECC. The coefficient of variation grey correlation method was employed to analyze the urban WECC of each subsystem of Beijing, China from year 2008 to 2016. The coupling coordination degree of each subsystem were calculated. The results show that: (1) The evaluation index value of WECC in Beijing is on the rise from 0.3560 in 2008 to 0.7877 in 2016, which suggests that the index of WECC of Beijing is improving, and the social and economic development is within an affordable range of the water environment. (2) The rate of ecological water usage, the proportion of energy conservation and environmental protection in local financial expenditure and the per capita water resources are the top three indicators with great impact on WECC. (3) The correlation degree index of vigor subsystem, pressure subsystem, organization subsystem, state subsystem, and resilience subsystem with water environment carrying capacity system are 0.0958, 0.1169, 0.0252, 0.0328 and 0.2962 respectively. The subsystem with strong correlation with water environment is resilience subsystem, followed by pressure subsystem. (4) According to the index distribution of coordination degree, the coordination degree level is between 0.4032 and 0.4458, and the coupling degree of each subsystem is above 0.8, which belong to the high coupling level.

Quantum dots (QDs) are a kind of excellent nano fluorescent materials with complex optical properties. They are simultaneous photon absorber, emitter and scatterer, making it difficult to comprehensively and accurately understand their optical behaviors using conventional methods. Existing studies almost concentrated on their photon absorption and fluorescence features while few studies focused on their light scattering, on-resonance fluorescence (ORF), and so on. In this work, we report a study of the complex optical activities of CdTe QDs using a polarized resonance synchronous spectroscopy (PRS2), combined with Ultraviolet-visible (UV-vis) spectroscopy and fluorescence polarization technologies. This work reveals the complicated optical behaviors of CdTe QDs under the conditions of different ligand functionalization, concentration, incubation time, solvent polarity and provides information including scattering, ORF, UV-vis absorbance spectra, UV-vis extinction, absorption, and scattering cross-section spectra, Stokes-shifted fluorescence (SSF) depolarization and scattering to extinction ratio (SER), etc. Furthermore, we explored the mechanism of QDs as a fluorescent sensor to detect trace Hg2+ from the perspective of light scattering. The observation suggested that the binding of Hg2+ to the QDs leads to their aggregation, which might also contribute to the fluorescence quenching of QDs. Our work is critical for developing a comprehensive understanding of the optical properties of QDs and provides useful information for their actual applications.

In this work, we synthesized ultrabright carbon dots (U-CDs) with photoluminescence quantum yield (PLQY) up to ∼100% using CA and EDA as precursors. When studying their interaction with the Pb2+ ion, we found that the PL quenching degree is independent of the U-CDs concentration. This feature provides great convenience for practical detection, which allows the standard curve determination and practical detection to be conducted under different U-CDs concentrations with detection error less than 20%. Based on the experimental observations, a possible mechanism is proposed to explain this phenomenon. To our best knowledge, this work has never been reported before and provides a new idea for the design of novel fluorescent sensors.

A lake ecological environment health assessment index system is constructed based on DPSR (Driving forces-Pressure-State-Responses) framework. The simulated annealing projection pursuit (SA-PP) algorithm, which can analyze high-dimensional data, is introduced and provides a new way for lake ecological environment health evaluation and decision-making. Qionghai, a typical plateau lake in Sichuan, China, is taken as an example to introduce the application of this assessment system. The results suggest the water ecological environment of Qionghai basin is in a relatively healthy state from 2017 to 2020. The state subsystem has the largest weight, and the important influencing factors affecting the health of lake water ecological environment are the water environment characteristics, ecological characteristics and pressure subsystem in the State subsystem. Zooplankton Simpson diversity index, chlorophyll a, NH3-N and total nitrogen are the main influencing factors of lake ecosystem health in the lake ecosystem health system. The restriction factor of the pressure subsystem is per capita daily domestic water consumption. Therefore, improving water quality and controlling water consumption intensity become important factors to improve the health of water resources and water environment in Qionghai basin. This study provides a new way for lake ecological environment health evaluation and decision-making.

The mechanism of quantum dots (QDs) as fluorescent nano sensor to detect metal ions remains controversial. Herein, we investigate the mechanism from the perspectives of fluorescence polarization and light scattering, where CdTe QDs are employed as a model fluorescent sensor and Hg(2+& nbsp;)ion is used as a model quencher. When the QDs react with Hg2+, we observed that the fluorescence is quenched while light scattering is enhanced and the fluorescence anisotropy is increased. This indicates that Hg2+ destabilizes the QDs and drives them to agglomerate, which might be an important contributor to the fluorescence quenching. This work provides novel insights to explain the mechanism of QDs as fluorescent probe to detect metal ions.

In this work, ultrabright fluorescent carbon dots (U-CDs) were synthesized by using a strict twice iterative optimization strategy. Their relative photoluminescence (PL) quantum yield is close to 100%, exceeding most of the reported fluorescent CDs and greatly boosting the practical applications of fluorescent CDs in many fields. Then serving as fluorescent anti-counterfeiting ink was taken as an example to briefly introduce the application of the U-CDs. The PL emission of the U-CDs is quenched at the range of pH < 4 or pH > 11 and restored at the range of pH = 5-10. This pH-sensitive PL feature allows the U-CDs to be used as fluorescent ink for pH and UV dual information encryption. The written or printed information is invisible under daylight but visible under UV light. After acid treatment or alkali treatment, the information is invisible even under a UV lamp but visible after neutralization treatment. This work provides a standardized scheme for optimizing the synthesis conditions of fluorescent CDs and paves the way for large-scale production of high-performance fluorescent CDs.

Herein, we report a removing resonance fluorescence (RRF) technique for light scattering spectroscopy (RLS), which takes full advantage of the differences between resonance fluorescence (RF) and scattered light in different wavelength regions to achieve an accurate separation of them. Then MPA-capped quantum dots (QDs) sensing Hg2+ is employed as an example to introduce the implementation of this method. The results indicate that Hg2+ ions destroy the stability of QDs, causing them to agglomerate, which might contribute to fluorescence quenching of QDs. Our study provides a useful tool for separating RF and scattered spectra, which expands the application range of RLS.

根据水污染流动"源头-转化-汇人"过程,综合衡量工业、农业、生活源污染排放对成都市主要河流的环境影响,提出"驱动力D(人口、社会经济发展)-承载源C(工业、农业、生活源污染排放)-承载状态S(污染程度)-管理M(治理污染投资)"4个子系统的DCSM模型,构建包含3层结构26个指标的成都市河流水环境承载力综合评价指标体系.采用投影寻踪模型得到各指标的影响程度,进一步建立区域水环境承载力各评价指标权重,根据最佳投影方向确定成都市主要河流2014-2018年的水环境承载力综合评价特征值,并得到相应评价等级.研究结果表明:影响程度最大的3项指标依次为:工业源COD排放强度、国考断面地表水TP平均浓度、环保投资占GDP的比重;通过对各个指标的权重分析,表明承载状态子系统和承载源子系统对综合评价结果所起作用最为显著,其次是管理子系统,驱动力子系统作用最小;通过评价等级分析,结果表明:2014-2018年成都市河流水环境承载力综合评价指数逐渐增加,评价等级从Ⅲ级(一般,2014-2016年)转变为Ⅱ级(较强,2017-2018年),说明5年来成都市河流水环境承载力逐步增加.研究表明了基于DCSM模型的成都市河流水环境承载力综合评价结果具有实用性和可行性,可以为城市河流水环境承载力综合评价提供新的研究思路,为水环境规划与管理的科学决策提供依据.

网络结构和样本集复杂性是影响BP网络泛化能力的两个最重要因素.对一个给定的训练样本集,为了构造一个与样本集复杂性相匹配的网络结构,使BP网络具有最佳泛化能力,在分析BP网络的泛化能力(用检测误差E2表示)与网络结构和样本集复杂性之间关系的基础上,建立了含参数的BP网络检测误差E2与网络隐节点数H、样本的因子数n、样本数N和样本集的复相关系数R之间的一般关系表达式,并提出了用于定量描述样本集复杂性的"广义"复相关系数Rn的新概念.借助于222个复杂函数的模拟仿真实验,应用免疫进化算法,对表达式中的参数进行优化,得到参数优化后的网络检测误差E2的定量解析表达式;依据误差理论和灵敏度概念,对优化得到的最小检测误差E20的表达式进行了可靠性论证.在此基础上导出了具有最佳泛化能力的BP网络隐节点数H0与"广义"复相关系数Rn之间满足的H0-Rn反比关系式.分别用满足H0-Rn反比关系式的隐节点数和6个经验公式的隐节点数构造的BP网络用于100个模拟检测函数进行仿真实验,发现前者构造的BP网络具有最佳泛化能力(即最小检测误差)的函数个数达到76个,远远多于后者构造的BP网络具有最佳泛化能力的函数个数;还将二者构造的BP网络用于环境预测的7个具体实例,进行预测效果比较,结果表明,前者预测的相对误差绝对值的平均值和最大值小于或远小于后者的相应值.从而验证了由H0-Rn反比关系式得出的BP网络隐节点数计算公式的可行性和实用性,为具有最佳泛化能力的BP网络的结构设计指出了新途径.

With the intensified impact of human activities, most lakes have been severely disturbed and the lake ecosystem has been seriously damaged, which exerted a great impact on the living environment of human beings in the lake basins. The health of the lake ecosystem has gradually become one of the hot issues in recent years. In this study, the water resources carrying capacity (WRCC) was used to reveal the chain relationship between human activities and water environment in the economic development of the Dianchi Lake Basin in Kunming City of China during 2005–2015. Specifically, we chose 25 evaluation indicators related to the water environment and social-economic activities, classified them into six subsystems, i.e., the driving force subsystem (D), the water resources situation and consumption subsystem (S), the water resources pressure subsystem (P), the water environmental situation subsystem (E), the response subsystem (R), and the management subsystem (M), and built a comprehensive assessment system-DSPERM framework model. Simulated annealing-projection pursuit model which reflects the structure or feature of high-dimensional data was adopted to calculate the WRCC of the Dianchi Lake Basin during 2005–2015 by weighting each evaluation indicator and each subsystem of the DSPERM framework model. The results show that the WRCC of the Dianchi Lake Basin was in level III (medium carrying capacity) from 2005 to 2012. Since 2013, the WRCC has been at level II (strong carrying capacity), and from 2005 to 2015, it showed a gradual upward trend. The evaluation indicators of each subsystem varied greatly and exhibited different development trends. The indicators of the water resources pressure subsystem had the greatest impact on the WRCC, followed by the indicators of the water environmental situation subsystem and the water resources situation and consumption subsystem. We recommend that the DSPERM framework model and the simulated annealing-projection pursuit model constructed in this work can be used to analyze the dynamic changes of the WRCC over the years. They have the advantages of practicability and feasibility, and can provide the basis for the scientific decision-making and comprehensive management of regional water environment planning.

为了建立适用于广义环境系统评价的普适指数公式,针对传统的环境评价指数公式不具有普适、规范和通用的局限,提出适用于广义环境系统任意指标的参照值和规范变换式的设计原则和方法;该变换要求变换后的任意指标的各分级标准规范值都能被限定在各自的较小区间内,从而用规范值表示的任意指标皆“等效”于同一个规范指标;再分别用不同限定区间内生成的随机数模拟任意指标的不同分级标准的规范值,不同区间内生成的所有随机数组成不同分级标准的全部训练(学习)样本,借助免疫进化算法优化不同评价指数公式中的参数,得到适用于广义环境系统评价的9个(广义)普适指数公式,并论证了公式的可靠性.分别将9个普适指数公式用于北京市朝阳区19个监测井的9项指标的地下水水质的综合评价,以及用于郑州、西安、上海三市2000年可持续发展评价.结果表明:9个普适指数公式用于同一监测井水质的评价结果几乎完全相同,也与传统评价方法的评价结果基本一致;用于郑州、西安、上海三市可持续发展评价的结果分别是3级、3级、2级,比传统评价法更符合实际情况.9个普适指数公式使广义环境系统的评价变得简洁、规范、统一和通用;基于指标规范变换的评价指数公式的建模思想和方法对建立广义环境系统的普适智能评价模型有借鉴作用.

A preliminary evaluation system of general education teaching quality in universities was established based on Bloom's objective classification method from four aspects: teaching objectives, teaching content, implementation process and assessment methods, in view of the impersonality of the evaluation and assessment of teaching quality, the difficulty of evaluation for the supervisory department in teaching, and the difficulty of the refinement and quantification of teaching achievements. A grey relational analysis method was used to establish the evaluation criteria, and then the evaluation model of teachers' general education quality was established. The index system and evaluation model were applied to evaluate many young teachers’ education quality in a university. The evaluation results show that: the evaluation system can be used to evaluate the teaching ability of general courses of young teachers, rank them comprehensively, and find out the aspects to be improved. According to the teaching evaluation results, teachers can analyze their ranking among peers, and find out their own advantages and disadvantages. It has theoretical and practical significances for improving the teaching quality of general courses in universities.

以精馏塔理论塔板数计算为例介绍计算机辅助计算在化工原理课程中的应用,并研究回流比对理论塔板数的影响.首先对已知塔板数的精馏塔设计实例进行计算,验证程序的正确性;然后以一个工业案例介绍本方法在实际生产中的应用;为了培养学生的探索精神,最后探讨改变参数对理论塔板数的影响,并分析了原因:当回流比减小时,理论塔板数增加,主要是精馏段塔板数增加引起.当回流比以很小的间隔减小时,理论塔板数呈锯齿形增加,是由于提馏段塔板数呈锯齿状变化引起.进一步分析提馏段的操作线和料液组成发现,锯齿状变化是由于进入提馏段料液的液相组成波动所导致.