CNG加气站压缩机故障探讨

以往复式压缩机出现的故障为例,根据现场经验,重点分析了传动部件和气阀故障类型,针对可能出现的问题,提出维修、检测以及故障排查处理的方法,为减少机组故障、提高压缩机组故障诊断效率和节约机组整修时间提供可靠依据。     

Fine particulate matter (PM2.5/PM1.0) in Beijing, China: Variations and chemical compositions as well as sources

Particulate matter (i.e., PM_1.0 and PM_2.5), considered as the key atmospheric pollutants, exerts negative effects on visibility, global climate, and human health by associated chemical compositions. However, our understanding of PM and its chemical compositions in Beijing under the current atmospheric environment is still not complete after witnessing marked alleviation during 2013–2017. Continuous measurements can be crucial for further air quality improvement by better characterizing PM pollution and chemical compositions in Beijing. Here, we conducted simultaneous measurements on PM in Beijing during 2018–2019. Results indicate that annual mean PM_1.0 and PM_2.5 concentrations were 35.49 ± 18.61 µg/m³ and 66.58 ± 60.17 µg/m³, showing a positive response to emission controls. The contribution of sulfate, nitrate, and ammonium (SNA) played an enhanced role with elevated PM loading and acted as the main contributors to pollution episodes. Discrepancies observed among chemical species between PM_1.0 and PM_2.5 in spring suggest that sand particles trend to accumulate in the range of 1–2.5 µm. Pollution episodes occurred accompanied with southerly clusters and high formation of SNA by heterogeneous reactions in summer and winter, respectively. Results from positive matrix factorization (PMF) combined with potential source contribution function (PSCF) models showed that potential areas were seasonal dependent, secondary and vehicular sources became much more important compared with previous studies in Beijing. Our study presented a continuous investigation on PM and sources origins in Beijing, which provides a better understanding for further emission control as well as a reference for other cities in developing countries.     

Front propagation of gravity currents on inclined bottoms in linearly stratified fluids

Environmental Fluid Mechanics - Gravity currents propagating on an inclined bottom into stratified environment can be frequently encountered in nature or engineering fields. However, theoretical...     

Multifunctional graphene-based nanocomposites for simultaneous enhanced photocatalytic degradation and photothermal antibacterial activity by visible light

Environmental Science and Pollution Research - A new strategy for the wastewater treatment was proposed by combining polyvinylpyrrolidone-functionalized silver nanoparticles with reduced graphene...     

我国涉汞危废处置企业中汞分布特征及风险评价

为了解涉汞危废企业对周边环境的影响及其潜在风险,加强涉汞危险废物的监督管理,通过2007年至2013年对13个持环保部发证的涉汞危废处置企业每年一次的监督性监测,分析了我国涉汞危废处置企业不同环境介质中汞分布特征及其风险。研究结果显示,2007年至2013年我国涉汞危废处置企业土壤、地下水、无组织排放气体中汞的浓度范围分别为0.75~28.4 mg·kg-1、1.0×10-5~1.3×10-4mg·L-1、3.9×10-4~4.0×10-3mg·m-3。利用风险商的方法对不同介质中汞进行初步的生态风险评价,结果显示土壤中汞存在较高的风险(RQ≥1),除2009年和2012年,其他所有年份高风险的企业超过50%,风险商的范围为0.44~56.8,呈逐渐上升趋势。地下水中汞存在潜在的风险(0.1RQ1)。无组织排放气体中汞的风险较低(RQ≤0.1),可以忽略。     

生化防护服的发展概述

本文简述了生化防护服的发展历史,详细介绍了防护材料的研究现状,提出了生化防护服高科技化、多功能化、智能化、高性能和舒适化的发展趋势。     

新型防护材料与个体防护装备

本文详细介绍了个体防护装备中有关新型防护材料的研究现状,对未来新型防护材料的发展趋势做了初步的展望。     

多功能内层手套的研制

本文针对隔绝式防毒手套存在透气性、舒适性较差以及保温功能不佳等问题,研制了一种新型多功能内层手套,提高了防毒手套的舒适性和安全性。