Local and regional contributions to PM2.5 in the Beijing 2022 Winter Olympics infrastructure areas during haze episodes

• Regional transportation contributed more than local emissions during haze episodes. • Short-range regional transportation contributed the most to the PM_2.5 in the OIAs. • Low wind speeds and low PBLHs led to higher local contributions to Beijing. The 2022 Winter Olympics is scheduled to take place in Beijing and Zhangjiakou, which were defined as OIAs (Olympic infrastructure areas) in this study. This study presents the characteristics and source apportionment of PM_2.5 in the OIAs, China. The entire region of mainland China, except for the OIAs, was divided into 9 source regions, including four regions in the BTH(Beijing-Tianjin-Hebei) region, the four provinces surrounding the BTH and the remaining areas. Using CAMx/PSAT, the contributions of the nine regions to the PM_2.5 concentration in the OIAs were simulated spatially and temporally. The simulated source apportionment results showed that the contribution of regional transportation was 48.78%, and when PM_2.5 concentration was larger than 75 μg/m³ central Hebei was the largest contributor with a contribution of 19.18%, followed by Tianjin, northern Hebei, Shanxi, Inner Mongolia, Shandong, southern Hebei, Henan and Liaoning. Furthermore, the contribution from neighboring regions of the OIAs was 47.12%, which was nearly twice that of long-range transportation. Haze episodes were analyzed, and the results presented the importance of regional transportation during severe PM_2.5 pollution periods. It was also found that they were associated with differences in pollution sources between Zhangjiakou and Beijing. Regional transportation was the main factor affecting PM_2.5 pollution in Zhangjiakou due to its low local emissions. Stagnant weather with a low planetary boundary layer height and a low wind velocity prevented the local emitted pollutants in Beijing from being transported outside, and as a result, local emissions constituted a larger contribution in Beijing.     

带有耗能连梁的钢筋混凝土剪力墙结构地震损伤评估

为了评估目前广泛研究的新型带有耗能连梁的剪力墙结构损伤程度,提出了一种适用于该结构的损伤模型,并通过低周反复试验结果对损伤模型进行验证。提出了该结构的地震性能等级及相应的损伤指数范围,并通过地震作用的增量动力分析得到该结构的易损性曲线,对该结构进行地震损伤评估。结果表明:提出的损伤模型能较好描述带有耗能连梁的钢筋混凝土剪力墙结构的损伤发展,地震性能等级及相应的损伤指数范围能较好反映该种结构的破坏等级,得到的易损性曲线能较为有效评估该种结构的损伤程度,为基于性能的新型带有耗能连梁的剪力墙结构的抗震设计及损伤评估提供了参考。     

Catalytic ozonation performance and surface property of supported Fe3O4 catalysts dispersions

Fe₃O₄ was supported on mesoporous Al₂O₃ or SiO₂ (50 wt.%) using an incipient wetness impregnation method, and Fe₃O₄/Al₂O₃ exhibited higher catalytic efficiency for the degradation of 2,4-dichlorophenoxyacetic acid and para-chlorobenzoic acid aqueous solution with ozone. The effect and morphology of supported Fe₃O₄ on catalytic ozonation performance were investigated based on the characterization results of X-ray diffraction, X-ray photoelectron spectroscopy, BET analysis and Fourier transform infrared spectroscopy. The results indicated that the physical and chemical properties of the catalyst supports especially their Lewis acid sites had a significant influence on the catalytic activity. In comparison with SiO₂, more Lewis acid sites existed on the surface of Al₂O₃, resulting in higher catalytic ozonation activity. During the reaction process, no significant Fe ions release was observed. Moreover, Fe₃O₄/Al₂O₃ exhibited stable structure and activity after successive cyclic experiments. The results indicated that the catalyst is a promising ozonation catalyst with magnetic separation in drinking water treatment.     

地质灾害系统的经济弹性及其结构研究

经济弹性是降低地质灾害系统经济损失的主要方式,如果能够对其进行准确定义和精确测量,其降低灾害损失的有效性将得到进一步增强.为此,在比较区分生态、工程、组织、规划、心理等不同学科领域弹性概念基础上,结合地质灾害系统的基本构成,对其经济弹性进行了操作化定义和数学描述.进而,在描述了地质灾害系统作用过程后,指出地质灾害系统的经济弹性是一个四维结构的概念,这对于准确衡量地质灾害经济弹性,提升其效率与潜力具有重要的作用.     

烟气中NOx脱除技术的研究进展

综述了干法脱硝、湿法脱硝、微生物法和化学吸收-生物还原法脱除烟气中氮氧化物的原理、技术特点和存在的问题。指出：化学吸收-生物还原法是未来脱除烟气中氮氧化物的主要研究方向之一,可通过提高NO在水中的溶解性,利用微生物去除氮氧化物,力争将其从实验室研究推广至工业应用。     

珠江口和邻近海域沉积有机质的来源及其沉积通量的时空变化

分析了珠江口和邻近海域沉积有机质(OM)的总有机碳(TOC)、总氮(TN)及稳定碳同位素组成〔δ(13C)〕等地球化学参数,并对有机质的来源和沉积通量进行了研究. 结果表明,珠江口沉积有机质来自大陆(52%)和水生(48%)混合来源;而邻近海域沉积有机质主要为水生来源(93%). 珠江口陆源有机质含量〔w(T－OC)为5.4 　mg/g〕远远高于邻近海域(0.49 　mg/g),近年来珠江口TOC和陆源有机质(T-OC)的平均沉积通量分别为5.57和2.2～3.6 mg/(cm2·a),说明珠江河口接受了大量的陆源有机物的输入,这是由于自20世纪后期的几十年以来,华南地区经济快速增长造成大量土地开垦,以及工农业生产和生活污水的排放所致. 珠江口和邻近海域的水生有机质沉积通量在近年均呈增加趋势,在珠江口达到最大值3.6 mg/(cm2·a),说明大量的营养物质导致水体的富营养化,从而促使水域初级生产力的增长.      

The association between heavy metal soil pollution and stomach cancer: a case study in Hangzhou City,China

Stomach cancer (SC) is a severe health burden, with nearly half of the world’s cases found in China. Noticeably, the emissions of heavy metals into the environment have increased alongside rapid urbanization and industrialization in China. However, as regards carcinogenic associations, the relationship between heavy metals and SC is yet unclear. Based on 9378 newly diagnosed SC cases in Hangzhou City from 2009 to 2012, this work is concerned with the quantitative characterization of the spatial distribution pattern of SC incidence and its geographical association with soil heavy metals by means of a novel geographical model. The results show that (a) Cd is one of the severe soil pollutants in Hangzhou; (b) higher SC incidence clusters are in central Hangzhou, whereas lower clusters are found in the northeast and southwest with a male to female incidence ratio about 2.2:1; (c) although when considered separately, the heavy metals in this work do not have a considerable impact on the distribution of SC incidence in Hangzhou City, nevertheless, the joint effects of multiple heavy metals have significant impacts on SC risk. The present work calls for a rigorous quantitative assessment of the integrated heavy metal soil pollution and its effects on SC incidence.     

“十五”期间牡丹江河段水质评价方法的探索与研究

概率法评价河流水质是一种简单易行可操作性强的方法,本文尝试利用概率法的原理和方法对牡丹江3个监测断面的“十五”期间监测数据进行分析,评价结果更符合实际水质情况,根据评价结果,可以为阶段性的环境管理提供可靠的技术支持,可以为环境保护工作提供防治依据,确保了牡丹江流域水环境的可持续发展。     

循环经济视角下的旅游产业生态化研究

旅游循环经济指导下的旅游产业生态化是实现旅游持续发展的战略途径。基于此,文章尝试将循环经济的理念应用到推进旅游产业生态化中,在循环经济“3R”原则指导下,提出了实现旅游产业生态化的策略,包括旅游企业内部的生态化、旅游企业间的生态化以及旅游产业与其他产业间的生态化。     

钢筋混凝土梁裂缝宽度的有限元分析

文章根据所做试验情况,对钢筋混凝土梁的裂缝宽度进行了有限元模拟.有限元分析结果与试验结果吻合良好.说明有限元分析在某种程度上可以代替试验对钢筋混凝土梁裂缝宽度进行研究分析.