不同粘土矿物材料对Cu2+的吸附特征

探讨了在不同矿物投加量、不同振荡时间、不同Cu2 浓度、不同矿物颗粒细度和不同pH条件下,钠基膨润土、膨胀蛭石和沸石3种粘土矿物对Cu2 的吸附效果,并比较了3种粘土矿物对Cu2 的吸附差异性.结果表明:对Cu2 的吸附效果依次为钠基膨润土＞沸石＞膨胀蛭石;较高的pH有助于粘土矿物对溶液中Cu2 的吸附,但考虑到实际操作的其他因素,不能把pH调得过高.     

产电微生物基因组及代谢网络分析

产电微生物的生物信息学分析是微生物燃料电池(Microbial Fuel Cell,MFC)研究中的关键环节,各种生物信息学分析方法已经开始应用于产电微生物研究.本文综述了目前产电微生物基因组、功能基因组和代谢网络分析的重要方法,包括基因和基因表达信息分析、基因组和比较基因组分析、代谢网络建模和计算机模拟等,其中,产电微生物代谢网络的构建是联系上游基因组分析和下游基因工程改造的关键,是目前相关研究面临的挑战.生物信息学分析必将促进干实验与湿实验的紧密结合,促进发现电子转移相关功能基因,解析微生物产电机制,优化代谢网络,由此指导基因工程改造产电微生物,最终提高产电效率.     

化感链霉菌6803菌株液体发酵工艺优化的研究

土壤微生物链霉菌6803菌株被证明对高等植物具有化感作用。采用单因子实验方法,研究液体发酵碳源、氮源、无机盐、发酵温度、发酵液初始pH值、摇床转速、发酵时间等对链霉菌6803菌株菌丝体产量及发酵液化感作用的影响,用均匀试验设计法优化了发酵工艺条件。结果表明：链霉菌6803菌株生长和产生化感作用的最佳发酵条件为：p（淀粉）=26．67g·L-1,p（蔗糖）=25．15g·L-1,p（NH4C1）=0．30g．L-1,黄豆饼粉浸液8．88％,所（NI-h）H2P04]=O．18g·L-1,p（FeS04．7H20）=O．002g·L-1,p（NaCl）=0．75g·L-1,pH值7．6,装量系数O．16,接种量3％,温度36℃,转速200r·min-1,发酵144h。本研究为利用微生物次生代谢产物作为天然除草剂奠定了基础。     

沉积物中2,2′,4,4′-四溴联苯醚(BDE-47)在铜锈环棱螺体内的毒代动力学及其繁殖毒性

多溴联苯醚(PBDEs)是一种全球性的新型持久性有毒污染物,沉积物中高浓度的PBDEs是水生态系统的巨大风险源,2,2′,4,4′-四溴联苯醚(BDE-47)在PBDEs同系物中,目前分布最广,生物毒性最强.为评价沉积物中BDE-47向底栖动物体内转移的潜力及其对底栖动物的潜在繁殖毒性,将实验室培养的铜锈环棱螺(Bellamya aeruginosa)暴露于BDE-47加标沉积物中,研究了BDE-47在铜锈环棱螺体内的毒代动力学特性及其对铜锈环棱螺潜在繁殖力的影响.结果表明,铜锈环棱螺对沉积物中BDE-47吸收较快,代谢速度相对较慢,BDE-47在铜锈环棱螺体内具有较强的生物积累性.生物积累达理论平衡时,铜锈环棱螺体内BDE-47浓度为1 440.67 ng·g-1(以样品于质量计).BDE-47在铜锈环棱螺体内的生物积累和生物净化过程较好地符合一级动力学模型,摄人速率常数、清除速率常数和生物-沉积物累积因子分别为0.10、0.038和2.75,生物半衰期为18d.铜锈环棱螺体内BDE-47达到90％稳定状态所需的理论时间约为60d.低浓度BDE-47(160 ng· g-1)暴露对铜锈环棱螺的潜在繁殖力没有影响,但当浓度≥640 ng·g-1时,铜锈环棱螺的繁殖力下降50％,这表明BDE-47对铜锈环棱螺具有繁殖毒性.铜锈环棱螺可作为指示沉积物中底栖生物长期暴露于BDE-47的良好检测模型.     

A 50-year sedimentary record of heavy metals and their chemical speciations in the Shuangtaizi River estuary (China): implications for pollution and biodegradation

Two parallel sediment cores collected from tidal flat located in the Shuangtaizi River estuary were analyzed for heavy metal concentrations and chemical speciations. Based on the ¹³⁷Cs activity profile, mean sedimentation rate at the sampling site during the past 50 years was estimated to be 1.3 cm·a^-1. Correlation analyses show that almost all the metals are associated with each other, suggesting that these metals might be derived from same sources and/or affected by same geochemical processes. Influence of total organic carbon (TOC) content on the concentrations of Cr, Ni, Cu and Cd is evident. Silt and clay contents, instead of sand content, play an important role in the distribution of these metals. The dominant binding phases for most of the metals (except for Cd) are the residual. The relative decrease of the residual fraction of Cd and Pb in the upper 66 cm of the core is striking. The distribution of chemical fraction confirms that the residual fractions of these metals have a natural origin, while only the non-residual fractions of Cd and Pb increased upward the core due to pollution in the past five decades. Pollution assessment on these heavy metals based on Index of Geoaccumulation (I_geo) also demonstrates that most of the metals are unpolluted. The weak pollution as observed in the sediments is perhaps related to a local plant, the Suaeda heteroptera Kitag, which may have played a significant role in the biodegradation of these metals and the metal distribution in the estuary.     

城市建设用地扩张的驱动力——基于省际面板数据的分析

为研究城市建设用地扩张的驱动力,论文利用1999-2008年全国31个省(市、自治区)的数据,使用计量工具分析了城市建设用地扩张与经济发展、城市人口增加和产业结构调整之间的关系,得到以下主要结论:①全国、东部、中部和西部地区城市建设用地扩张速度都很快,东部地区最快,但增长率近年呈现下降趋势,而中部地区和西部地区增长速度相对较慢;②经济发展、城市人口增加和产业结构调整能够非常好地解释全国及东部、中部和西部地区城市建设用地的扩张,3个变量对城市建设用地扩张均有着正影响,但影响力度存在差异;③逐年回归结果表明经济发展、城市人口增加和产业结构调整对城市建设用地的扩张也同样有着正影响,城市人口增加对城市用地扩张的影响基本保持稳定,且力度大于经济发展和产业结构调整的影响,经济发展因素的影响力度越来越大,产业结构调整的影响力度逐渐减弱。     

Exposure assessment,chemical characterization and source identification of PM2.5 for school children and industrial downwind residents in Guangzhou,China

To assess the exposure doses of PM_2.5 and to investigate its chemical components for the subpopulation (i.e., school children and industrial downwind residents), simultaneous sampling of indoor and outdoor PM_2.5 was conducted at an elementary school close to traffic arteries and a residence located in the downwind area of a steel plant in metropolitan Guangzhou in 2010. Chemical components, i.e., organic carbon, elemental carbon and 6 water soluble ions were analyzed in PM_2.5. A survey was also conducted to investigate the time-activity patterns of the school children and the industrial downwind residents. Indoor and outdoor PM_2.5 were 63.2 ± 20.1 and (76.7 ± 35.8) μg/m³ at the school, and 118.8 ± 44.7 and 125.7 ± 57.1 μg/m³ in the community, respectively. Indoor PM_2.5 was found to be highly related to outdoor sources, and stationary sources were the significant contributors to PM_2.5 at both sites. The daily average doses of PM_2.5 for the school children at the school (D _children) and the industrial downwind residents in the community (D _residents) were (7.6 ± 1.9) and (36.1 ± 36.8) μg/kg-day, respectively. The daily average doses of particulate organic mass and SO₄ ^2? were the two most abundant chemical components in PM_2.5. PM_2.5 exposure for the school children was contributed by indoor and outdoor environments by 48.8 and 51.2 %, respectively; for the industrial downwind residents, the contributions were 66.0 and 34.0 %, respectively. Age and body weight were significantly and negatively correlated with D _children, while age, body weight and education level were significantly and negatively correlated with D _residents; gender was not a significant factor at both cases.     

不饱和聚酯树脂钮扣粉尘静电爆炸敏感性研究

针对某不饱和聚酯树脂钮扣厂在除尘设备维修过程中发生的粉尘爆炸事故,探究静电引起此次事故的可能性并提出防护措施。通过实验测定不饱和聚酯树脂钮扣粉尘的爆炸特性参数,进而确定其静电爆炸敏感性。结果发现:不饱和聚酯树脂钮扣粉尘云最小点火能MIE为4～10 mJ、最低着火温度MIT为480 ℃、粉尘层最低着火温度LIT＞400 ℃。表明,此粉尘属易燃粉尘,其粉尘爆炸敏感度极高,被静电火花点燃的可能性极大,在生产过程中,应采取静电防护措施。     

爆炸冲击波及高温耦合引起瓦斯二次爆炸特性研究

在煤矿安全事故中,破坏程度最严重的事故之一就是瓦斯爆炸,而瓦斯爆炸冲击波及火焰锋面可能会二次点爆其他位置积聚瓦斯,加速火焰锋面及冲击波传播,并能产生更高的超压,造成更大的人员伤亡及财产损失。借助详细反应机理GRI Mech 3.0,基于开源化学动力学软件Cantera,研究冲击波强度、瓦斯体积分数和冲击波及高温耦合条件下对瓦斯爆炸特性的影响。结果显示,冲击波诱导瓦斯爆炸中,点火延迟时间随着瓦斯体积分数的增大而出现增大现象,随冲击波强度的增大而降低;同时分析了二氧化碳、一氧化碳和一氧化氮致害物质的浓度随瓦斯体积分数、冲击波强度和冲击波及高温耦合条件下的变化情况。     

大气CO_2浓度升高对稻田土壤Ca、Mg含量的影响

为了研究稻田生态系统中土壤钙、镁元素生物地球化学循环对大气CO2浓度升高的响应。利用中国稻/麦轮作FACE（Free Air Carbon-dioxide Enrichment）试验平台,研究大气CO2浓度升高（比周围大气高200μmol mol-1）对2007年稻季各生育期不同深度土壤溶液ρ（Ca）、ρ（Mg）的影响。结果表明,大气CO2浓度升高降低了5 cm处土壤溶液ρ（Ca）、ρ（Mg）,有增加稻季30、60和90 cm处土壤溶液ρ（Ca）的趋势,其增幅分别为18.3%、12.4%和15.3%;大气CO2浓度升高会增加稻季Ca淋溶损失风险;稻季不同深度土壤溶液ρ（Ca）、ρ（Mg）对大气CO2浓度升高的响应有所不同。稻田生态系统不同深度土壤Ca、Mg循环对大气CO2浓度升高的响应值得深入研究。