长江三角洲城市群霾的演变特征及影响因素研究

重建了长江三角洲1961~2007年霾气候数据序列,分析了霾日数的时空变化特征及城乡差异,并探讨了大气污染以及地面和近地层气象条件对霾发生的影响.结果表明,利用湿度—能见度指数参与霾气候序列重建的方法具有一定的合理性和科学性.过去47a间,长江三角洲霾日数总体上呈逐渐增多的趋势,并且四季霾日数都增加.空间上,整个长江三角洲霾日数基本上都呈增加趋势,并以杭州和南京增加最多.近30a来长江三角洲大城市、中等城市和城镇乡村站间霾日数变化具有明显差异.地面气象要素中风速和最长连续无降水日数与霾发生具有较好的对应关系.在霾天气过程和对应的清洁过程,近地层温度、位势高度和风场也都具有明显的差异.长江三角洲霾变化趋势与我国京津冀、珠江三角洲等地的变化一致.区域大气污染物排放量的增加,尤其是细颗粒物的增加是霾出现频率增加的可能原因,全球气候变化以及区域城市化造成的气象条件改变也有利于霾日的增加.     

δ13C and fatty acid composition of mesopelagic fishes in the South China Sea and their influence factors

Study of the ecology of mesopelagic fishes is central for assessing the active biological pump in the ocean, especially in the mesopelagic layers. The use of δ¹³C and fatty acid analysis can help to analysis the ecology of mesopelagic fishes. Here, we analysed the fatty acid composition of mesopelagic fishes from the continental northern slope of the South China Sea (NSSCS) and compared with nearshore SCS fishes and mesopelagic fishes collected from the Southern Ocean. The mesopelagic fishes had unusually high lipids, which resulted in Δδ¹³C values exceeding 1‰, more than the enrichment factor in the food web. The mesopelagic fishes had higher C18:1n-9/C18:1n-7 and C20:1n-9/ C18:1n-7 ratios compared with other fishes in the SCS, which confirmed that plankton were their main dietary source. The mesopelagic fishes from SCS and Southern Ocean had different ratios of C20:5n-3/C22:6n-3 (EPA/DHA), suggesting geographical locations and diet sources had obvious influence on their fatty acid composition. The SCS mesopelagic fishes had higher C20:4n-6/C22:6n-3 (ARA/DHA) and C20:4n-6/C20:5n-3 (ARA/EPA) ratios than mesopelagic fishes in the Southern Ocean, indicating the influence of physical factors on fatty acid composition. Thus, future studies of the fatty acids in mesopelagic fishes should consider both dietary sources and physical environments.     

The effect of imazethapyr on soil microbes in soybean fields in northeast China

Large quantities of herbicides are used on agricultural soils, but the effects of herbicides on the structure of the soil microbial community have not been well investigated. In this study, soil from three soybean fields was investigated. The herbicide imazethapyr was applied in one year to soil 1 and in two sequential years to soil 2. Control soil received no imazethapyr. Microbial biomass and community structure were characterised using chloroform fumigation–extraction and phospholipid fatty acid (PLFA) determination. The imazethapyr residue was 1.62 μ g·kg^?1 in soil 1 and 1.79 μ g·kg^?1 in soil 2. The microbial biomass carbon and total PLFAs for soil 2 were much higher than for the other soils. PLFA profiles showed that fatty acids for Gram-negative and Gram-positive bacteria, as well as total bacteria and total fungi in soil 2 were higher than in other samples. Principal component analysis of the PLFAs showed that the structure of the microbial community differed substantially among the three different soybean field soils. Application of the herbicide imazethapyr to soybean fields clearly changed the soil microbial biomass and shifted the structure of the microbial community.     

我国水资源学术交流十年总结与展望

水资源是基础性的自然资源和战略性的经济资源,是一个国家综合国力的有机组成部分。目前,国家已将水资源列为与粮食、石油资源并列的三大战略资源之一。随着经济社会快速发展,水资源供需矛盾越来越突出,水资源已成为制约国民经济发展的重大"瓶颈"。因此,水资源研究已成为支撑我国可持续发展的重要学科领域。论文在大量文献分析的基础上,阐述了水资源研究发展过程;介绍了近十年来中国自然资源学会水资源专业委员会主办的主要学术交流情况,总结了近期我国水资源研究进展;在以上分析的基础上,对水资源学科发展趋势进行了分析,并对近期水资源研究进行展望,提出未来十年我国水资源学术交流发展方向。     

软骨藻酸神经毒性作用机制研究进展

在拟菱形藻引发的有毒赤潮中产生的记忆缺失性贝毒(amnesic shellfish poison,ASP)软骨藻酸,经贝类等海洋生物摄入进入食物链,在对海洋生物造成危害的同时,也对人类健康造成威胁。软骨藻酸中毒者临床上表现为呕吐、腹痛和头痛等症状,严重者出现神经系统功能紊乱,如昏迷、抽搐和记忆缺失。软骨藻酸结构上与兴奋性氨基酸谷氨酸相似,它可以通过直接活化KA(kainate)受体和AMPA(α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)受体介导兴奋性神经毒。本文主要从线粒体功能紊乱、内质网应激和神经炎症等方面就软骨藻酸的神经毒性作用机制进行了综述。     

Higher sorption of arsenate versus arsenite on amorphous Al-oxide, effect of ligands

Arsenic pollution is currently a major health issue because As is toxic for human beings, animals, and plants. Knowledge of As mobility is therefore important to assess health risk. The sorption of arsenite and arsenate on metal oxides in the presence of various anionic ligands is closely linked to the mobility, bioavailability, and risk. It was reported that the sorption mechanisms and characteristics of arsenite and arsenate on Al-oxides were different from that on Fe-oxides. Previous work reports the sorption of arsenite and arsenate on Fe-oxides in the presence of ligands. Whereas there is few knowledge on the sorption of arsenite and arsenate by Al-oxides in the presence of ligands. Here, we studied the sorption of arsenite and arsenate on amorphous Al-oxide by batch experiments. We tested the effect of organic ligands: oxalate, malate, tartrate, citrate; and inorganic ligands: sulfate, phosphate, selenate, selenite. Results show that amorphous Al-oxide has more sorption affinity for arsenate than arsenite. The inhibition of As sorption by ligands at pH 6 is higher for arsenite than arsenate. For arsenite, the As sorption inhibition decreases in the order phosphate, citrate, malate, selenite, oxalate, tartrate, sulfate, and selenate. For arsenate, the As sorption inhibition decreases in the order phosphate, malate, citrate, selenite, tartrate, oxalate, sulfate, and selenate.     

微囊藻毒素对青菜生长的影响及其在生物体内的累积

蓝藻藻泥好氧堆肥腐熟后还田是其打捞后资源化利用的主要途径。堆肥后仍有一定数量的微囊藻毒素(microcystin,MC)残留,大量还田是否会对作物生长和人类健康产生安全风险尚不明确。将青菜(Brassica chinensis)暴露于不同MC含量的石英砂和菜地土壤,观测植株生长状况及体内MC含量,并观测不同含量的MC在菜地土壤中的降解速率。结果发现:砂培实验结束时,青菜成株的株高和生物量随着MC暴露浓度的增加而显著降低,而植株地上部MC的含量则显著增加。在MC浓度为0.386mg·kg-1的处理中,青菜地上部MC-LR(L为亮氨酸)和MC-RR(R为精氨酸)的浓度分别达到27.45μg·kg-1(鲜质量)和1.35μg·kg-1(鲜质量)。MC-LR和MC-RR在青菜地上部的富集系数都随着砂培基质中MC浓度的增加而显著降低,且前者显著高于后者。土培青菜生长过程中吸收和累积的MC数量显著小于砂培实验。MC在菜地土壤中降解56d后,MC-LR和MC-RR的降解率均达90%以上。按普通有机肥的一般用量(2.5kg·m-2)施用充分腐熟的蓝藻堆肥成品种植青菜,食用后每人每天摄入的MC含量远低于WHO制定的饮用水中MC的指导值。研究为评估现行蓝藻堆肥工艺中残留的MC对作物生长和生物安全风险提供了科学依据。     

汶川8.0级地震时徐州台地震动和形变同震响应分析

通过对汶川8.0级地震和6次强余震时徐州地震台的形变同震响应和地震位移量研究,计算了汶川地震主震发生时地震面波到达徐州的时间和位移量,统计了汶川8.0级地震及其强余震引起的同震阶变时间参数、幅度参数和阶跃形态。研究结果表明:①该台4套形变观测均有较高的同震响应能力,同震阶变的开始时间与主震面波到达徐州台的时间基本吻合,可以认为同震应变阶和同震波是由强震面波引起的,是一种叠加在体应变固体潮曲线上的高频变化,并呈现快速振荡衰减的形式。②同台同岩性的不同形变观测对同一个地震的响应是不同的,阶跃形状、响应大小、响应时间、变化幅度都有较大的差别,这种差别更多的是反映了仪器本身的性能、观测精度、频率响应的不同,并不是应力场变化和构造特征的差异。③汶川地震引起的徐州地区应力变化以压应力为主,大地震的动态应力触发作用对远场的应变变化具有重要影响。     

330MW火电机组一次调频分析与优化

针对国电宁夏石嘴山发电有限公司一次调频响应缓慢、调频幅度与设定值偏差较大等问题,对产生原因进行分析,提出优化方案。结果表明:数字式电液控制系统(DigitalElectronic Hydraulic control system, DEH)一次调频存在滞后环节,严重影响调频速率及调频幅度,经过参数优化后,一次调频功能满足了电网调频要求。     

煤矿工业废水处理工艺技术及效益分析

我国煤炭资源十分丰富,开采过程中产生大量废水,为了减少煤矿废水治理的投资及运行费用,详尽阐述了实用、可行、高效的处理技术及工艺组合,并在煤矿废水处理中取得良好的处理效果,分析得出煤矿废水经深度处理回用后具有良好经济、环境效益。