密封充氢环境条件下固态电化学氢气传感器效应试验研究

目的研究密闭充氢环境下固态电化学氢气传感器效应。方法设计能模拟低氧、低氢和压力变化的密闭充氢环境,并在此环境中进行一系列氢气传感器效应试验,分析、评定试验数据。结果得到了不同环境下氢气、氧气浓度随时间变化的规律,提出固态电化学氢气传感器的有效工作环境,并预测了其在不同贮存环境下的工作寿命。结论密闭充氢环境内压力和温度的变化对固态电化学氢气传感器影响较大,湿度影响较小,注气检定合格的氢气传感器,在密封容器内扩散式检定,不合格率高,检定数据误差大于±5%FS。     

两种改性剂对多氯联苯污染土壤协同热脱附影响研究

采用热脱附技术处理多氯联苯污染土壤已经成为了一种主要的场地修复方式。为提高热脱附效率,降低能耗,以典型电力电容器污染土壤为对象,采用2种改性剂(零价纳米铁和氢氧化钠)研究协同热脱附下多氯联苯的去除效率、分布特性及毒性当量。结果表明纳米铁和NaOH存在的条件下,有效提高了多氯联苯和毒性当量的去除效率,在较低温度下尤其显著,因此添加改性剂能够有效地促进热脱附过程。纳米铁的协同热脱附机理为显著强化了热脱附过程的传质传热,同时伴有一定的脱氯降解。NaOH的添加在较低温度下实现了较强的脱氯降解作用,加氢脱氯机理可用来解释协同热脱附过程中多氯联苯的脱氯反应过程。上述研究结果为多氯联苯污染土壤的场地修复提供理论基础。     

Air pollution characteristics and their relationship with emissions and meteorology in the Yangtze River Delta region during 2014–2016

With rapid economic growth and urbanization, the Yangtze River Delta(YRD) region in China has experienced serious air pollution challenges. In this study, we analyzed the air pollution characteristics and their relationship with emissions and meteorology in the YRD region during 2014–2016. In recent years, the concentrations of all air pollutants, except O_3,decreased. Spatially, the PM_(2.5), PM_(10), SO_2, and CO concentrations were higher in the northern YRD region, and NO_2 and O_3 were higher in the central YRD region. Based on the number of non-attainment days(i.e., days with air quality index greater than 100), PM_(2.5) was the largest contributor to air pollution in the YRD region, followed by O_3, PM_(10), and NO_2.However, particulate matter pollution has declined gradually, while O_3 pollution worsened.Meteorological conditions mainly influenced day-to-day variations in pollutant concentrations. PM_(2.5) concentration was inversely related to wind speed, while O_3 concentration was positively correlated with temperature and negatively correlated with relative humidity.The air quality improvement in recent years was mainly attributed to emission reductions.During 2014–2016, PM_(2.5), PM_(10), SO_2, NO_x, CO, NH_3, and volatile organic compound(VOC)emissions in the YRD region were reduced by 26.3%, 29.2%, 32.4%, 8.1%, 15.9%, 4.5%, and0.3%, respectively. Regional transport also contributed to the air pollution. During regional haze periods, pollutants from North China and East China aggravated the pollution in the YRD region. Our findings suggest that emission reduction and regional joint prevention and control helped to improve the air quality in the YRD region.     

白蚁肠道共生微生物多样性及其防治方法研究现状

白蚁是破坏性极大的世界性害虫.结合课题组多年来开展的科研工作,综述了白蚁肠道中内生菌分离和白蚁防治方法的研究现状.已从白蚁肠道内分离出原生动物、细菌、真菌和螺旋体等多种生物.白蚁肠道中存在的微生物对白蚁消化木质纤维素类食物有着重要的作用.白蚁防治方法主要为物理方法、化学方法和生物学方法.生物防治白蚁方法具有高效、低毒、无残留、无污染、价廉的特性.介绍了以从抗白蚁树木分离到的内生菌生物发酵合成的代谢产物作为杀白蚁生物药剂的生物防治方法,该方法优势明显,有可能成为未来白蚁防治剂研究的方向,为白蚁防治提供重要途径,具有广阔的应用前景.     

微生物絮凝剂的研究与应用进展

微生物絮凝剂是具有广阔应用前景的一种天然高分子絮凝剂，因而引起科学界的高度重视．自７０年代以来，美国和日本等十多个国家已对其进行了详细的研究．本文综述了微生物絮凝剂的研究与应用进展，包括合成絮凝剂的微生物种类、微生物絮凝剂的化学本质、遗传基础和微观结构、微生物絮凝剂的絮凝机理和絮凝能力及其影响因素，微生物絮凝剂的合成条件和提取方法等方面．文中还给出了微生物絮凝剂在污染治理等领域实际应用的若干事例．     

河网水质模型研究进展

纵观水质模型的研究、应用及相关科学的发展,本文针对现有的水质模型做了分析评价,简要介绍了河网水质模型的未来研究趋势,并提出了几点建议。     

下翼缘摩擦式自定心钢框架梁柱节点抗震性能的数值模拟

介绍了一种新型的钢框架梁柱节点形式,其中预应力钢绞线提供了结构在地震作用下的复位功能(自定心),设置在梁端下翼缘的摩擦件则为结构提供了耗能能力;介绍了下翼缘摩擦式自定心钢框架梁柱节点的构造和工作原理,以节点的低周反复加载试验结果为依据,利用面向对象的开放式计算程序OpenSees建立了节点的数值模型,并侧重于模拟节点在...     

Exploring the effects of population growth on future land use change in the Las Vegas Wash watershed: an integrated approach of geospatial modeling and analytics

The Las Vegas Valley metropolitan area is one of the fastest growing areas in the southwestern United States. The rapid urbanization has presented many environmental challenges. For instance, as population growth and urbanization continue, the supply of sufficient clean water will become a concern. In addition, the area is also experiencing the longest drought in history, and the volume of water storage in Lake Mead, the main fresh water supply for the entire region, has been reduced greatly. The water quality in the main stem of the Las Vegas Wash (LVW) and Lake Mead may also be significantly affected. In order to develop effective sustainable management plans, the very first step is to predict the plausible future urbanization and land use patterns. This paper presents an approach to predict the future land use pattern at the LVW watershed using a Markov cellular automata model. The multi-criteria evaluation was used to couple population density as a variable depicting the driving force of urbanization in the model. Moreover, landscape metrics were used to analyze land use changes in order to better understand the dynamics of urban development in the LVW watershed. The predicted future land use maps for the years 2030 and 2050 show substantial urban development in the area, much of which are located in areas sensitive to source water protections. The results of the analysis provide valuable information for local planners and policy makers, assisting their efforts in constructing alternative sustainable urban development schemes and environmental management strategies.     

Trends of ischemic heart disease mortality attributable to household air pollution during 1990–2019 in China and India: an age-period-cohort analysis

Environmental Science and Pollution Research - Cardiovascular diseases (CVD) caused by household air pollution (HAP) have sparked widespread concern globally in the recent decade. Meanwhile,...     

REVIEW ON GLOBAL NATURAL DISASTERS IN 2000

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