双波长气溶胶粒径传感方法及其火灾烟雾探测器

提出了双波长光散射气溶胶粒径传感方法,设计实现了采用该方法的双波长火灾烟雾探测器。使用短波长和长波长的双波长光源,通过计算其光功率比值,利用其与中值粒径的关系函数获得气溶胶粒径,并根据不同粒径下的气溶胶浓度分别给出大小不同粒径的火灾烟雾或干扰气溶胶提示。因而,不仅可以有效区分大小不同粒径的火灾烟雾气溶胶,以正确探测火灾,而且能够识别微米级的大粒径干扰粒子,降低火灾误报率,可以应用于飞机等航空器空中密闭的特殊环境。     

3种人工湿地基质材料对氨氮的吸附特性

对陶粒、石英砂和砾石这3种人工湿地基质材料进行了氨氮（NH₄⁺-N）吸附特性研究.通过扫描电镜和BET比表面积分析仪对材料进行表征分析,发现陶粒表面相比石英砂和砾石更为粗糙,内部孔隙也较发达,陶粒（18.97 m²·g^-1）比表面积高于石英砂和砾石.在纯氨氮溶液和模拟污水厂出水一级B标准的混合溶液中,3种基质对NH₄⁺-N的吸附能力均表现为：陶粒>砾石>石英砂.陶粒对NH₄⁺-N的饱和吸附容量在混合溶液中最大（63.55 mg·g^-1）.陶粒对NH₄⁺-N的吸附过程符合伪二级动力学模型（在纯氨氮溶液中R²为0.99、在混合溶液中R²为0.98）.在纯氨氮溶液中运用Freundlich和Langmuir模型对等温吸附试验结果进行拟合,发现Freundlich模型（R²=0.93）描述陶粒的吸附特性比Langmuir模型更为精确（R²为0.93）,表明陶粒对NH₄⁺-N的吸附为多层吸附.综上所述,陶粒的吸附容量较强,在混合溶液中吸附容量较纯氨氮溶液增大了31%,适用于作为人工湿地基质填料.     

Multilevel air quality evolution in Shenyang: Impact of elevated point emission reduction

Visibility observed at different altitudes is favorable to understand the causes of air pollution. We conducted 4-years of observations of visibility at 2.8 and 60 m and particulate matter(PM) concentrations from 2015 to 2018 in Shenyang, a provincial city in Northeast China. The results indicated that visibility increased with the increasing height in winter(especially at night), and decreased with height in summer(especially at the daytime). PM concentration exhibited opposite vertical variati...     

厌氧氨氧化菌富集培养过程微生物群落结构及多样性

为深入理解厌氧氨氧化菌富集培养过程微生物群落变化特征,采用ASBR反应器进行厌氧氨氧化菌富集培养,考察了不同培养时间微生物群落组成、多样性及物种网络关系.结果表明,通过逐步提高基质浓度,实现了厌氧氨氧化菌富集,NH₄⁺-N和NO₂^--N去除率分别为97.6%和95.4%,总氮去除率为84.9%.高通量测序发现,整个培养过程优势菌门（相对丰度>5%）为变形菌门（Proteobacteria）、拟杆菌门（Bacteroidetes）、绿弯菌门（Chloroflexi）、浮霉菌门（Planctomycetes）、装甲菌门（Armatimonadetes）和放线菌门（Actinobacteria）;富集培养获得的主要厌氧氨氧化菌为Candidatus Brocadia,相对丰度从1.42%增长到24.66%;培养过程,微生物群落优势菌群组成未发生变化,但相对丰度呈现显著差异（P<0.05）.富集培养过程不同时间,微生物群落α多样性呈现先升高后降低的趋势,且存在显著差异（P<0.05）;微生物群落β多样性在富集培养过程发生明显空间分异特征,且存在显著差异（R=0.5672,P<0.01）.培养过程不同时间,物种网络密度分别为0.188、0.068、0.059、0.18和0.0735;虽然富集培养过程导致微生物间的关联作用变弱,但浮霉菌门相关类群的物种成为网络中的主要节点.     

甘氨酸厂氨氮废水治理的工艺及实验研究

运用多效真空蒸发兼热泵技术回收甘氨酸厂高氨氮废水中的氯化铵,通过实验找到了治理此废水的最佳真空度,克服了采用常规蒸发方法的能耗大、料液对设备腐蚀性强的缺点。最后运用吹脱法对蒸发冷凝水进行了治理,通过实验得到了吹脱的最佳工艺参数吹脱时间6h、pH125、吹脱温度60℃,为运用生化法彻底解决甘氨酸厂高氨氮工业废水的污染难题奠定了基础。     

单级SBR生物膜中全程自养脱氮的研究

研究了具有全程自养脱氮作用的生物膜中无机碳源浓度、pH值、溶解氧(DO)对全程自养脱氮的影响.结果表明,当NaHCO3浓度从1.75g/L上升到2.50g/L时,反应体系中的pH值从7.6～8.0上升到8.8左右,氨氮转化率和总无机氮去除率分别急剧下降到53%和48.8%.在进水氨氮负荷为60g/(m³·d)时,最佳DO应控制在0.5～0.7mg/L,此时氨氮转化率达到90%以上.     

高效液相色谱法测定全氟辛酸铵

全氟辛酸铵是聚四氟乙烯生产废水中的重要污染物,本文采用高效液相色谱对全氟辛酸铵进行定量分析,通过流动相的离子抑制法,达到了满意的检测效果。     

Aerosol transmission,an indispensable route of COVID-19 spread: case study of a department-store cluster

• Aerosol transmission is an indispensable route of COVID-19 spread. • Different outbreak sites have different epidemiologic feature. • SRAS-CoV-2 can exist for a long time in aerosol. • SRAS-CoV-2 RNA can be detected in aerosol in diverse places. • Some environmental factors can impact SARS-CoV-2 transportation in aerosol. Patients with COVID-19 have revealed a massive outbreak around the world, leading to widespread concerns in global scope. Figuring out the transmission route of COVID-19 is necessary to control further spread. We analyzed the data of 43 patients in Baodi Department Store (China) to supplement the transmission route and epidemiological characteristics of COVID-19 in a cluster outbreak. Incubation median was estimated to endure 5.95 days (2–13 days). Almost 76.3% of patients sought medical attention immediately upon illness onset. The median period of illness onset to hospitalization and confirmation were 3.96 days (0–14) and 5.58 days (1–21), respectively. Patients with different cluster case could demonstrate unique epidemiological characteristics due to the particularity of outbreak sites. SRAS-CoV-2 can be released into the surrounding air through patient’s respiratory tract activities, and can exist for a long time for long-distance transportation. SRAS-CoV-2 RNA can be detected in aerosol in different sites, including isolation ward, general ward, outdoor, toilet, hallway, and crowded public area. Environmental factors influencing were analyzed and indicated that the SARS-CoV-2 transportation in aerosol was dependent on temperature, air humidity, ventilation rate and inactivating chemicals (ozone) content. As for the infection route of case numbers 2 to 6, 10, 13, 16, 17, 18, 20 and 23, we believe that aerosol transmission played a significant role in analyzing their exposure history and environmental conditions in Baodi Department Store. Aerosol transmission could occur in some cluster cases when the environmental factors are suitable, and it is an indispensable route of COVID-19 spread.     

异养硝化-好氧反硝化菌脱氮同时降解苯酚特性

研究了异养硝化-好氧反硝化菌Diaphorobacter sp. PDB3去除氨氮同时降解苯酚的特性.在最佳碳氮比7和摇床转速160r/min下,该菌在21h内对初始浓度365mg/L苯酚的降解率达94.9%,总有机碳去除率达90.8%,同时40mg N/L氨氮被完全去除,中间代谢物硝态氮和亚硝态氮逐渐积累并在后期降低.氮平衡分析表明,52.3%的氨氮转化为胞内氮,37.2%转化为氮气,菌株主要通过细胞同化作用和异养硝化-好氧反硝化作用去除氨氮.检测到羟胺氧化酶、硝酸还原酶及亚硝酸还原酶活性,表明菌株PDB3具有完整的异养硝化-好氧反硝化偶联途径.随着苯酚浓度升高,抑制作用增强,脱氮效率降低.     

蒸汽相变促进可溶PM2.5凝结增长的数值分析

为利用蒸汽相变原理促进氨法脱硫系统排放细颗粒物(PM2.5)的脱除,建立多分散颗粒的凝结增长动力学模型,利用数值模拟方法研究了可溶硫酸铵颗粒的凝结增长规律,并将典型粒径可溶与不可溶颗粒的凝结增长过程进行对比分析.结果表明:不同粒径硫酸铵颗粒的增长速率相近,等温系统的凝结增长效果优于绝热系统;对于同一初始粒径分布下的可溶和不可溶颗粒,微米尺度可溶颗粒的增长速率始终大于不可溶颗粒,亚微米尺度可溶颗粒的增长速率先大于而后小于不可溶颗粒,使得二者的增长曲线存在一个交叉点;蒸汽饱和度增大能显著促进硫酸铵颗粒的增长;等温系统中温度对硫酸铵颗粒的增长影响显著,绝热系统中温度的影响较弱.