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A potential threat from biodegradable microplastics: mechanism of cadmium adsorption and desorption in the simulated gastrointestinal environment

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Frontiers of Environmental Science & Engineering 2024年第2期18卷 63-75页

作者： Timing Jiang Xiang Wu Shushan Yuan Changfei Lai Shijie Bian Wenbo Yu Sha Liang Jingping hu Liang huang huabo Duan yafei Shi Jiakuan Yang School of Environmental Science&Engineering Huazhong University of Science and TechnologyWuhan 430074China School of Resources and Environmental Science Hubei UniversityWuhan 430062China hubei Provincial Engineering Laboratory for Solid Waste Treatment Disposal and Recycling Wuhan 430074China School of Civil Engineering Architecture and EnvironmentHubei University of TechnologyWuhan 430068China State Key Laboratory of Coal Combustion Huazhong University of Science and TechnologyWuhan 430074China

It has been demonstrated that microplastics (MPs) can accumulate heavy metals from the environment and transfer them into organisms via the food chain. However, adsorption and desorption capacities for biodegradable MPs relative to those for conventional MPs remain poorly understood. In this study, cadmium (Cd(II)) adsorption and desorption characteristics of polylactic acid (PLA), a typical biodegradable MP, were investigated. Two conventional MPs, i.e., polypropylene (PP) and polyamide (PA) were used for comparison. The maximum Cd(II) adsorption capacities of the MPs studied in the adsorption experiments decreased in the order PA (0.96 ± 0.07 mg/g) > PLA (0.64 ± 0.04 mg/g) > PP (0.22 ± 0.03 mg/g). The Pseudo-second-order kinetic model and Freundlich isothermal model described the Cd(II) adsorption behaviors of PLA MPs well. X-ray photoelectron spectroscopy and two-dimensional Fourier transform infrared correlation spectroscopy analysis indicated that oxygen functional groups were the major and preferential binding sites of PLA MPs, which contributed to their high Cd(II) adsorption capacities. Simulated gastric and intestinal fluids both significantly enhanced the desorption capacities of the examined MPs. Notably, degradation of the PLA MPs during in vitro human digestion made the Cd(II) on the PLA MPs more bioaccessible (19% in the gastric phase and 62% in the intestinal phase) than Cd(II) on the PP and PA MPs. These results indicate the remarkable capacities of biodegradable MPs to accumulate Cd(II) and transfer it to the digestive system and show that biodegradable MPs might pose more severe threats to human health than conventional nonbiodegradable MPs.

关键词： Biodegradable microplastics Cadmium Adsorption and desorption Gastrointestinal environment Two-dimensional correlation spectroscopy Bioaccessibility

Fly Ash and Slag as Partial Replacement of Cement for the Synthesis of Low Carbon Cementitious Materials

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Journal of Renewable Materials 2023年第5期11卷 2491-2511页

作者： yafei hu Keqing Li Lujing Zheng Bin Han School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of Ministry of Education of China for Efficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing100083China Mining College Guizhou UniversityGuiyang550025China

Tailings known as solid waste are generated by the mining industry.The development of tailings as wet shotcrete aggregates has significant economic and environmental benefits.The fine particle size of the tailings results in a large consumption of traditional cement as a cementitious material and insignificant improvement in strength.Therefore,a composite cementitious system of cement and solid waste resources(fly ash and slag powder)is explored for this study.In this paper,the response surface methodology(RSM)is used to optimize the experimental design and a multivariate nonlinear response model with cement,fly ash and slag powder contents as variables are constructed,which can investigate the effect of the composite cementitious system on the strength of tailing wet shotcrete(TWSC).In addition,the information entropy(IE)is introduced and combined with the RSM to evaluate the composite cementitious system.Finally,the desirability function(DF)combined with RSM is used to optimize the composite cementitious system.The results show that the response model constructed in this paper has R^(2)=0.96 and P-value<0.01(the test result of the model is P-value<0.01),which indicates that the model has high reliability.The higher the content of slag powder and cement in the composite cementitious system,the higher the strength and comprehensive score of the TWSC.There is a critical value of fly ash content,which makes the maximum cementation of the composite cementing system.The optimal mix proportion of the composite cementitious system is obtained based on RSM-DF,which leads to the strength of TWSC at different curing time to achieve the expected index.

关键词： Tailings wet shotcrete composite cementitious system desirability function mix proportion optimization

Development of Wet Shotcrete with Solid Waste as Aggregate:Strength Optimization and Mix Proportion Design

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Journal of Renewable Materials 2023年第9期11卷 3463-3484页

作者： yafei hu Keqing Li Bo Zhang Bin Han School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of Ministry of Education of China for Efficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing100083China

The super-fine particle size of tailings is its drawback as a recycled resource,which is reflected in the low strength of the new construction and industrial materials formed when it is mixed with cement and other cementitious materials.Therefore,it is crucial to study the effect of tailings particle size and cementitious material on the strength of tailings wet shotcrete(TWSC)and to investigate the optimal mix proportion.In this paper,a multivariate nonlinear response model was constructed by conducting central composite experiments to investigate the effect of different factors on the strength of TWSC.The strength prediction and mix proportion optimization of TWSC are carried out by machine learning techniques.The results show that the response model has R^(2)>0.94 and P<0.01,which indicates that the model has high reliability.Moreover,the strength of TWSC increases with the increase of tailings fineness modulus and decrease of water-binder ratio,while it also increases and then decreases with the increase of replacement rate of slag powder to cement(SRC rate).The extreme learning machine(ELM)constructed in this paper predicts the strength of TWSC with an accuracy of more than 98%and achieves rapid prediction under multi-factor conditions.It is worth mentioning that the ELM combined with the genetic algorithm(ELM-GA)collaboratively solved to obtain the mix proportion for C15 and C20 strength grades of TWSC and the maximum error is verified by experiments to be less than 2%.

关键词： Tailings wet shotcrete solid waste recycling prediction model

A Modeling Method for Predicting the Strength of Cemented Paste Backfill Based on a Combination of Aggregate Gradation Optimization and LSTM

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Journal of Renewable Materials 2022年第12期10卷 3539-3558页

作者： Bo Zhang Keqing Li Siqi Zhang yafei hu Bin Han School of Civil and Re source Engineering University of Science and Technology Beijing Beijing100083China Key Laboratory of Ministry of Educ ation of China for Eficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing 100083China

Cemented paste backill(CPB)is a susta inable mining technology that is widely used in mines and helps to improve the mine environment.To investigate the relationship between aggregate grading and different affecting factors and the uniaxial compressive strength(UCS)of the cemented paste backill(CPB),Talbol gradation theory and neural networks is used to evaluate aggregate gradation to determine the optimum aggregate ratio.The mixed aggregate ratio with the least amount of cement(waste stone content river sand content=7:3)is obtained by using Talbol grading theory and pile compactness function and combined with experiments.In addition,the response surface method is used to design strength speaific ratio experiments.The UCS prediction model which ues the ISTM and considers the aggregates gradation have high accuracy.The root mean square error(RMSE)of the prediction results is 0.0914,the coefficient of determination(R^(2))is 0.9973 and the variance account for(VAF)is 99.73.Compared with back propagation neural network(BP-ANN),extreme lea ming machine(ELM)and madal basis function neural network(RBF ANN),LSTM can efectively characterize the nonlinear relationship between UCS and individual affecting factors and predict UCS with high accuracy.The sensitivity analysis of different affecting factors on UCS shows that all 4 factors have significant effect on UCS and sensitivity is in the following ranking:cement content(0.9264)>slurry concentration(0.9179)>aggregate gradation(waste rodk content)(0.9031)>curing time(09031).

关键词： Backill aggregate gradation machine learning uniaxial compressive strength cemented paste backill

基于GARCH-Copula-CVaR模型的中国碳金融市场风险估测研究

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特区经济 2024年第2期421卷 66-70页

作者：胡亚菲昆明理工大学管理与经济学院云南昆明650500

碳金融市场发展的核心问题是风险问题,本文基于欧盟与我国各碳金融市场交易数据及收益序列选择最优Copula函数,建立极值理论下的GARCH-Copula-CVa R模型实证测度风险,并用失败频率检验法(Kupiec)对结果进行回测检验。结论为:为不高估碳... 详细信息

碳金融市场发展的核心问题是风险问题,本文基于欧盟与我国各碳金融市场交易数据及收益序列选择最优Copula函数,建立极值理论下的GARCH-Copula-CVa R模型实证测度风险,并用失败频率检验法(Kupiec)对结果进行回测检验。结论为:为不高估碳市场风险,需要考虑汇率与碳价的实际相互作用;对欧盟及我国各碳金融市场的市场风险进行量化,其中风险最大的为上海市碳金融市场,风险最小的为全国碳金融市场;国家经济环境及地方政策等因素的不同都会对市场风险大小产生影响。

关键词：市场风险区域碳金融最优Copula模型

矿用纤维增强沙漠砂混凝土拉伸力学性能试验研究

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中国矿业 2024年第6期33卷 218-226页

作者：周亚菲胡红倩李志军胡建王轩库尔勒金川矿业有限公司新疆库尔勒841008 新疆大学地质与矿业工程学院新疆乌鲁木齐830047

混凝土作为现代锚网喷联合支护的重要组成部分,在控制地下矿山巷道围岩变形方面发挥着重要作用。针对传统矿用混凝土成本较高且在拉伸应力作用下容易出现开裂的实际问题,开发了一种使用沙漠砂作为细骨料,聚乙烯醇(PVA)纤维作为增强材料... 详细信息

混凝土作为现代锚网喷联合支护的重要组成部分,在控制地下矿山巷道围岩变形方面发挥着重要作用。针对传统矿用混凝土成本较高且在拉伸应力作用下容易出现开裂的实际问题,开发了一种使用沙漠砂作为细骨料,聚乙烯醇(PVA)纤维作为增强材料的新型矿用纤维增强沙漠砂混凝土。为验证该新型支护材料的力学性能,选取沙漠砂粒径、水胶比、纤维长度和纤维掺量作为变量,共制备尺寸为330 mm×60 mm×13 mm的狗骨试件36个,探讨其对混凝土弹性模量、抗拉强度、极限拉应变等性能的影响。研究结果表明,用沙漠砂替换普通河砂,材料的弹性模量和极限拉应变均呈现出增大的趋势,分别达到3.70 MPa和4.01%,新疆沙漠砂的优良性质得到充分发挥,为巷道支护等工程提供了更经济有效的选择。掺入国产PVA纤维能够有效增强沙漠砂混凝土的抗拉强度和变形能力。与河砂相比,沙漠砂粒径较小且表面光滑,使其在基体中分布较为均匀,能够提高混凝土抵抗裂缝能力,并且沙漠砂与PVA纤维之间的协同作用也更为有效,纤维能够更好地滑移,并抵抗裂纹的发展。沙漠砂属于中细砂,能够较好地与其他原材料发生作用。本文考虑到西部矿区沙漠砂资源丰富,研究开发的矿用纤维增强沙漠砂混凝土在西部沙漠矿区巷道支护领域具有一定的应用前景。

关键词：地下矿山巷道沙漠砂混凝土纤维增强材料拉伸力学性能

基于凝聚层次聚类的接地网定向支路减维腐蚀诊断优化方法

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高电压技术 2024年第4期50卷 1723-1730页

作者：谢炀杨鑫黄亚飞朱子茵黎昊聪胡君瑶长沙理工大学电气与信息工程学院长沙410114

为了更有效地对接地网水平支路导体的腐蚀故障情况进行诊断,采用模型仿真方法对基于电网络理论的接地网腐蚀诊断方法进行分析,针对现有接地网腐蚀诊断模型存在的缺陷,提出了一种基于凝聚层次聚类的接地网定向支路减维腐蚀诊断优化方法... 详细信息

为了更有效地对接地网水平支路导体的腐蚀故障情况进行诊断,采用模型仿真方法对基于电网络理论的接地网腐蚀诊断方法进行分析,针对现有接地网腐蚀诊断模型存在的缺陷,提出了一种基于凝聚层次聚类的接地网定向支路减维腐蚀诊断优化方法。该方法通过分析恒定直流激励下接地网各支路电阻变化对于端口的灵敏度规律,利用支路端口灵敏度对接地网可及端口进行凝聚层次聚类,以选出最优端口测量组合;然后采用定向支路减维方法对各端口电阻方程进行支路筛选,将灵敏度低于判定阈值的导体支路划为未知支路,高于判定阈值的导体支路划为健康支路,以降低腐蚀诊断模型的病态程度和计算维度。在某模拟变电站接地网上对该方法进行了仿真验证,结果显示优化后的整体诊断相对误差仅为3.07%,远小于普通接地网腐蚀诊断的6.74%,证明该方法能显著提高接地网腐蚀诊断精度,可为接地网腐蚀诊断提供理论指导。

关键词：接地网腐蚀诊断支路端口灵敏度凝聚层次聚类定向支路减维

Neutrophil CC1 plays a protective role in orthotopic liver transplantation: views from the perspective of natural compounds

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Chinese Journal of Natural Medicines 2023年第4期21卷 241-242页

作者： FANG yafei hu Qinghua School of Pharmacy China Pharmaceutical UniversityNanjing 211198China

Orthotopic liver transplantation(OLT)is the mainstay treatment for malignant liver cancer and end-stage liver diseases.Nevertheless,liver ischemia-reperfusion injury(IRI),which is regarded as a major risk factor for primary graft dysfunction,acute or chronic tissue rejection and organ damage[1],greatly limits the indication of liver resection and the application of marginal donor liver,seriously hindering the application of liver transplantation.

关键词： Orthotopic liver transplantation Ischaemia-reperfusion injury NETosis CC1 Autophagy

基于CiteSpace的我国城市公共空间活力研究进展

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林业调查规划 2024年第2期49卷 207-213页

作者：胡俊强燕亚飞河南科技大学园艺与植物保护学院河南洛阳471000

城市公共空间是城中居民进行公共交往活动的重要场所,空间活力研究对未来城市的发展具有重大意义,收集中国知网1997—2021年间456篇国内城市公共空间活力相关的研究文献,利用CiteSpace软件绘制知识图谱,从发文作者、发文机构、关键词等... 详细信息

城市公共空间是城中居民进行公共交往活动的重要场所,空间活力研究对未来城市的发展具有重大意义,收集中国知网1997—2021年间456篇国内城市公共空间活力相关的研究文献,利用CiteSpace软件绘制知识图谱,从发文作者、发文机构、关键词等方面,对国内城市空间活力的研究现状进行可视化分析。研究结果显示,城市活力、活力营造、活力测度是当前城市空间活力研究领域的热点;空间活力研究尺度由宏观转向微观,研究方法由定性转向定量研究;在研究尺度方面,逐渐由早期的宏观视角转向中微观视角,对空间活力的研究更偏向具体细节的考究,更关注其本身的物质环境;活力的测评方法仍需继续完善,空间营造策略方面要继续深化相关研究。

关键词：空间活力城市空间 CiteSpace 文献综述知识图谱