零价铁对水中四氯化碳还原脱氯研究

文章研究了Fe0的纯度、粒径和投加量以及酸洗预处理对水溶液中四氯化碳的还原性脱氯作用的影响,并对其脱氯的主要产物——氯仿进行了讨论。结果表明:(1)Fe0纯度越高,粒径越小,四氯化碳的去除效果越好;(2)在实验范围内,Fe0投加量越大,四氯化碳的去除效率越高;(3)酸洗后,四氯化碳的去除效果明显的提高;(4)Fe0纯度、粒径和投加量以及酸洗处理对四氯化碳的还原产物氯仿亦具有一定的影响,四氯化碳的去除与氯仿的产生之间存在着一定的对应关系。     

The value of energy efficiency programs for US residential and commercial buildings in a warmer world

US residential and commercial buildings were responsible for about 41 exajoules (EJ) of primary energy use per year in 2002, accounting for approximately 9% of the world fossil-fuel related anthropogenic carbon (C) emissions of 6.7 Gt that contribute to climate change. US Government-sponsored building energy efficiency research and implementation programs are focused on reducing energy consumption in US residential and commercial buildings and reducing these carbon (C) emissions. Although not specifically intended for adaptation to a warmer climate and less effective than under today’s cooler climate, these programs also could help reduce energy demand in a future warmer world. Warming scenarios projected by the United Nations Intergovernmental Panel on Climate Change (IPCC) in 2001 imply net overall decreases in both site energy and primary energy consumption in US residential and commercial buildings, largely because of the reduced need for heating. However, there would be as much as a 25% increase in building space cooling demand and a significant part of the increase could be offset by energy-efficiency improvements in buildings. Overall, in the US, buildings-related energy efficiency programs would reduce site energy consumption in buildings in the US by more than 2 EJ in 2020 and primary energy by more than 3.5 EJ, more than enough to offset the projected growth in cooling energy consumption due to climate change and growth in the US building stock. The savings would have an estimated annual net value at 2005 energy prices of between $45.0 and $47.3 billion to consumers.

投加混凝剂活性污泥法优选混凝剂试验研究

选取五种常用无机混凝剂,把活性污泥与生活污水按一定比例混合后,进行混凝试验,结果表明,三氯化铁去除TP的效果最好,在投加量为99 mg/l时,可去除污水中88%的TP。三种混凝剂FeCl3、PFS、PAFC与PAM复合进行参数优化的正交试验,对TP有最佳处理效果的絮凝条件为：投加FeCl3,投加量为99 mg/l,投加顺序为FeCl3先投加1 min,以污泥恰搅起不分层的速度搅拌（约160 r/min）30 min。试验结果对投加混凝剂活性污泥法选择合适的混凝剂有借鉴作用。     

Cloacal erection promotes vent apposition during forced copulation in the New Zealand stitchbird (hihi): implications for copulation efficiency in other species

Cloacal protuberances (CP) in male birds result from spermatic engorgement of storage tubules around the cloaca during the breeding season. We examined seasonal changes in the volume and orientation of the CP in the New Zealand stitchbird Notiomystis cincta. The male stitchbird has one of the largest recorded CPs for any species (max = 1,570 mm³), with CP volume increasing by almost 400% between the non-breeding and breeding seasons. While sperm competition has been positively correlated with the magnitude of CP storage in other species, no evidence previously existed for the CP improving copulation efficiency. By measuring the relative orientation of the CP throughout the year, we show that not only does the CP increase in size as males become sexually active, it also changes its orientation by approximately 60°. This results in it shifting from facing posteriorly to becoming almost perpendicular to the abdomen. This cloacal erection improves the apposition of the male and female cloacal openings during face-to-face forced copulation in this species. This provides the first reported evidence supporting the copulation efficiency hypothesis of the avian CP. While the magnitude of seasonal changes in female cloacal volume was similar to males, female cloacal orientation remained virtually unchanged across seasons. This difference between the sexes is likely to reflect differing selection pressures for optimizing sperm transfer. In females, a posterior-facing cloaca is ideal for both waste evacuation and sperm reception, whereas, for the male, a posterior-facing cloaca is well suited for waste evacuation, but possibly hinders sperm delivery. Changes in male cloacal orientation from the non-breeding to the breeding season are a likely reflection of conflict in this dual function. Evidence of changes in CP orientation in another passerine species suggests this phenomenon is widespread and also important for understanding related fields such as sperm competition, forced copulation and constraints on the evolution of the avian intromittent organ.     

南水北调中线干渠生态系统结构与功能分析

为分析和掌握南水北调中线干渠生态系统结构与功能的特征参数,根据2015~2019年中线干渠鱼类资源调查数据及实测的鱼类生物学参数数据,应用Ecopath with Ecosim 6.6软件构建了Ecopath食物网模型.模型由18个功能组组成,包括了初级生产者、初级消费者、主要鱼类和有机碎屑等.结果显示：中线干渠生态系统规模总流量、总生产量和总消耗量分别为19186.330,8947.857和1106.002（t/（km²·a））,食物网主要由4个整合营养级（1.00~3.71）构成,最高营养级为大型肉食性鱼类鱤（3.71）.食物网能量传递主要有两条途径,分别为牧食食物链和碎屑食物链,两者传递的能量相当,但牧食食物链传递效率是碎屑食物链的近两倍.交互营养分析结果表明,捕食者对其饵料生物的影响一般为抑制作用,碎屑生物量的增加对大部分功能组的影响为正效应,小型上层鱼类对浮游动物生物量起抑制作用.从各功能组之间的生态位重叠来看,各功能组间捕食者生态位重叠现象不普遍,重叠指数适中,部分肉食性鱼类的捕食者生态位重叠指数达到1.对生态系统总体特征分析发现,中线干渠生态系统的总初级生产量与总呼吸量的比值（P/R）、总初级生产量与总生物量的比值（P/B）、Finn's循环指数（FCI）和Finn's平均路径长度（FML）都表明该生态系统处于发展的幼态期,抵抗外界干扰的能力差.此外,中线干渠生态系统对初级生产力的利用率很低,导致过多的营养物质未进入更高营养级的食物链中进行循环,造成系统能量流动的滞缓.因此,根据生物操纵理论,可通过优化和完善鱼类群落结构,增强对系统初级生产力的利用效率,促进物质循环和能量流动,维持生态系统稳定.     

Comparison of light absorption and oxidative potential of biodiesel/diesel and chemicals/diesel blends soot particles

Soot particles,mainly coming from fuel combustion,affect climate forcing through absorbing light and also result in adverse human health outcomes.Though biodiesel or additives blending with diesel was considered environmentally friendly,the understanding on absorbing and oxidative capacity of soot emitted from them are still unclear.The watersoluble organic carbon(WSOC) content,surface chemical structure,light absorption and oxidative potential(OP~(DTT)) of soot from biodiesel/diesel and chemicals/diesel blends were investigated utilizing total organic carbon analyzer,X-ray photoelectron spectrometer,ultraviolet–visible spectrophotometry and dithiothreitol(DTT) assay.The differences and correlations between soot properties were statistically analyzed.Chemicals/diesel blends soot owned significantly higher WSOC content,ratio of mass absorbing efficiency(MAE) in250 and 365 nm(E_2/E_3),OP~(DTT),and higher surface carbonyl content.Coconut biodiesel/diesel blends soot contained evidently higher aromatic carbon–oxygen single bond(Ar_C–O)content,and higher MAE365.The individual comparison of biodiesel/diesel blends showed20% coconut biodiesel blend owned the lowest WSOC,E_2/E_3 and OP~(DTT),while highest Ar_C–O and MAE365,representing strongest absorbing properties.Association analysis showed OP~(DTT)was significantly positively correlated with WSOC.Further,the evident negative correlation between MAE365 and OP~(DTT) was observed.Our results showed coconut biodiesel/diesel blends soot induced lower levels of oxidative potential,whereas absorption of light was higher,which have far reaching consequences on climate forcing.Therefore,it is important to evaluate the balance point between light-absorbing properties and oxidative potential,under the wide use of biodiesel.     

Effects of disinfection efficiency on microbial communities and corrosion processes in drinking water distribution systems simulated with actual running conditions

The effects of disinfection efficiency on microbial communities and the corrosion of cast iron pipes in drinking water distribution systems (DWDSs) were studied. Two annular reactors (ARs) that simulated actual running conditions with UV/Cl₂ disinfection and chlorination alone were used. High chlorine consumption and corrosion rate were found in the AR with UV/Cl₂. According to functional genes and pyrosequencing tests, a high percentage of iron recycling bacteria was detected within the biofilm of the AR with Cl₂ at early running stage, whereas siderophore-producing bacteria were dominant in the biofilm of the AR with UV/Cl_2. At the early running stage, the sequential use of UV light and an initial high chlorine dosage suppressed the biomass and iron-recycling bacteria in both bulk water and biofilms, thereby forming less protective scales against further corrosion, which enhanced chlorine consumption. Non-metric multidimensional scaling analysis showed that the bacterial communities in the ARs shaped from within rather than being imported by influents. These results indicate that the initial high disinfection efficiency within the distribution system had not contributed to the accumulation of iron-recycling bacteria at the early running stages. This study offer certain implications for controlling corrosion and water quality in DWDSs.     

冰雪和降水中黑碳的分布特征与来源研究进展

黑碳（black carbon,BC）影响着全球辐射平衡、大气环境和人体健康,而降水是大气中黑碳的主要去除方式.简述了降水中黑碳的分析方法,重点论述了国内外降水中黑碳的分布特征和对黑碳的去除效率,以及模型和碳同位素示踪技术在识别黑碳来源的应用.结果表明:①单颗粒黑碳光度计因其检测限低、分析速度较快等优点在分析液相介质黑碳中应用较多.②降水中黑碳含量在空间上呈现较大差异,中国降水中黑碳含量较两极地区高2~3个数量级,越靠近两极地区,降水中黑碳含量越低,且工业革命后冰芯中黑碳含量有所增加.由于不同地区工业类型和化石燃料燃烧效率的差异,中国降水中黑碳含量大于东亚其他地区及欧洲地区.长时间（>8 h）降水对黑碳的去除效果较好.③混合单粒子拉格朗日积分轨迹模型、正定矩阵因子分解模型和碳同位素示踪技术相结合能更好地分析降水中黑碳的来源.研究显示,我国降水中黑碳含量较高、污染较重,但对城市降水中黑碳污染的关注还不足,未来应加强对不同地区城市降水中黑碳的观测,充分利用分析模型和碳同位素示踪技术解析降水中黑碳的来源.      

活性污泥中的腐殖酸对实时荧光定量PCR的影响

活性污泥基因组中的腐殖酸会影响实时荧光定量PCR检测的准确性.本研究采用抽提基因组前腐殖酸去除试剂盒、抽提基因组后腐殖酸去除试剂盒、抽提基因组前后共同去除试剂盒3种不同的方法,去除活性污泥基因组中的腐殖酸,经过PCR和实时荧光定量PCR方法的验证找出腐殖酸去除的最适方法;通过DNA酶Ⅰ消化基因组DNA保留杂质腐殖酸,向其中掺入已知浓度的总细菌质粒,5个浓度10倍梯度稀释10 ng·μL~(-1)的定量模板,探究腐殖酸和梯度稀释模板对活性污泥总细菌实时荧光定量PCR的影响.结果显示,在不同处理组中,通过反复洗脱的方式在基因组抽提前去除活性污泥中的腐殖酸,DNA的得率(162.46 ng·μL~(-1))最多,A260/230值为1.34,A260/280值为1.80,腐殖酸的残留最少;去除腐殖酸后外加内标质粒组,梯度稀释10 ng·μL~(-1)模板100倍及以上,腐殖酸的抑制效应显著降低后保持不变(p0.05),100倍以内变化不显著(p0.05);抽提前去除腐殖酸组进行实时荧光定量PCR的抑制效率为6.16%,显著低于对照组的72.68%(p0.05).研究表明,抽提前去除活性污泥腐殖酸,抽提后将基因组模板稀释100倍可显著降低活性污泥实时荧光定量PCR的抑制效率,提高定量结果的准确性.     

原位空气扰动技术影响因素研究-基于苯污染非均质含水层

通过一维模拟柱实验,研究了分层非均质含水层下不同介质组合对原位空气扰动技术修复苯污染地下水的影响.结果表明：在曝气流量为0.1 L/min,分层非均质的介质渗透系数在同一数量级时,分层情况的改变对污染物的去除效率影响不大;当分层非均质的介质渗透系数不在同一数量级时,下层渗透系数变大会使砂柱上层污染物浓度先升高后降低的现象更加明显,而下层渗透系数变小会使砂柱上下层污染物的去除效率相差不大.分层情况下不同介质组合影响苯的平均去除效率,在分层非均质条件下,气流由低渗透介质进入高渗透介质,污染物的去除速率相对更快,污染物的平均去除效率主要取决于分层非均质上层介质,其污染物平均去除效率曲线与分层非均质上层介质均质大致相同.