资源与环境约束下的滨海新区海洋经济可持续发展途径

滨海新区资源丰富,经济规模不断扩大,呈现出良好的发展趋势,但也面临资源利用不合理、环境污染严重等问题.在分析天津滨海新区海洋经济发展现状和优势的基础上,探讨了该区域面临的资源与环境约束问题,并对这些问题进行了原因剖析,主要原因包括缺少科学规划引导、管理矛盾突出等.最后从建立环境与经济持续发展的综合决策机制、直接管制与间...     

加油站油气排放处理装置的研发与应用

通过对国内外加油站油气排放处理工艺方法调研,结合国内加油站实际情况,进行膜组件筛选、实验室测试、工业化测试,完成了带净化器的膜式冷凝加油站油气排放处理装置的研发,在北京15座加油站应用效果较好。     

Heavy metal distribution of natural and reclaimed tidal riparian wetlands in south estuary, China

The characteristics of heavy metals in water, soils and plants of NRWs are significantly different from those in the RTRWs which are strongly affected by human activities.     

东北某市严重雾霾期PM_(2.5)、PM_(10)中元素特征和富集因子分析

为了掌握雾霾期大气PM 2.5和PM 10中无机元素污染特征,于2013年10月20~31日期间采集了东北某市发生严重雾霾时大气PM 2.5和PM 10样品,分析了颗粒物样品中21种无机元素(K、Ca、Na、Mg、Mn、Pb、Cd等)的浓度。结果表明:大气PM 2.5和PM 10浓度普遍超标,超标率分别达88.89%、66.67%;大气PM 2.5和PM 10中元素质量浓度主要是由Na、S、Ca、K、Fe、Al、Si、As、Mg 9种元素贡献;元素的富集状况分析表明,Na、Zn、Ca、Cr、Ni、Cu、Mn、Cd、Pb和As在非雾霾期和雾霾期期富集程度较高,污染较严重,受人为污染源影响较大;以不同元素做参比,所得各元素富集系数不同。     

南淝河沉积物污染特征及评价研究

对南淝河当涂路桥上游至董铺水库河段的沉积物进行系统地分析,测定了有机质、总磷（ TP）、总氮（ TN）及重金属Pb、Cr、Zn的含量。研究了沉积物中各个测定指标的垂直分布规律,各采样点的污染指标含量均呈现随着取样深度的增加而减少。用地累积指数法和潜在生态危害系数法对沉积物中重金属污染作出了评价,结果表明,南淝河沉积物中重金属含量属于轻度生态危害。对沉积物中的有机质和有机氮运用有机指数和有机氮评价法进行评价,发现南淝河沉积物中的有机质和有机氮均处于超标状态。     

北京农贸市场常见淡水鱼体内抗生素残留调查研究

基于改进的超高效液相色谱-串联质谱(UPLC-MS/MS)的分析方法,通过对不同重量鲤鱼、鲫鱼、草鱼和鲢鱼中四环素类、磺胺类以及喹诺酮类等十种抗生素的残留测定,调查了北京市场水产品中抗生素的污染水平。结果表明,在所有样品中,只有磺胺二甲基嘧啶、麻保沙星、诺氟沙星和恩诺沙星四种抗生素检出,检出率分别为2.1%,4.2%,16.7%,46.9%,其他抗生素未检出。检出的四种抗生素中,磺胺二甲基嘧啶和麻保沙星只在草鱼中有检出,诺氟沙星和恩诺沙星在四种鱼中均有检出。恩诺沙星的浓度在鲤鱼、鲫鱼、草鱼和鲢鱼中依次降低。只有部分检出恩诺沙星超出50μg·kg-1的最大允许残留量。磺胺二甲基嘧啶、麻保沙星、诺氟沙星随着鱼重量的增大而变高,最高浓度为34.8、179.6、39.4μg·kg-1,而在个头小的鱼中未检出,这可能由生物累积造成。总之,北京市场的水产品存在抗生素的污染,但是大多数的抗生素的浓度都低于最大允许残留量。仍需加强水产品养殖环节中抗生素使用的管理。     

The Influence of Tip Leakage Flow on Flowfields in a Highly Loaded Transonic Rotor with Forward Sweep

A three-dimensional numerical simulation on a highly loaded transonic rotor with zero, 0.2 mm, 0.3 mm, and 0.5 mm tip gap, respectively, is performed in this article. The flowfields above 60% span of transonic rotors are affected by leakage flow, but the stall margin of rotor has obviously improved with small tip gap. Typical leakage vortex structures with double cores are generated by the interaction of incoming flow, leakage flow, and second flow in flowfields, and then the two vortex cores merge into a stronger one in front of shock. The shape of passage shock changes seriously by strong leakage vortex after interaction and a large low-velocity region generates behind shock in tip region. The blockage, produced by leakage flow and boundary layer separation, induces detached shock wave near leading edge of rotors and triggers the rotating stall of compressor. However, with tip gap increasing, the blockage produced by leakage flow tends to be dominant in occurrence of rotating stall. Once the tip clearance adds to 0.5 mm, vortex breakdown in tip region of rotor appears and the flow deteriorates drastically, which aggravates the onset of stall in rotor.     

A 1-dodecanethiol-based phase transfer protocol for the highly efficient extraction of noble metal ions from aqueous phase

A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an ethanolic solution of 1-dodecanethiol, and then extracting the coordination compounds formed between noble metal ions and1-dodecanethiol into a non-polar organic solvent. A number of characterization techniques,including inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrate that this protocol could be applied to extract a wide variety of noble metal ions from water to dichloromethane with an efficiency of 96%, and has high selectivity for the separation of the noble metal ions from other transition metals. It is therefore an attractive alternative for the extraction of noble metals from water, soil, or waste printed circuit boards.     

Alternative cropping systems for sustainable water and nitrogen use in the North China Plain

Serious water deficits and excessive nitrogen (N) applications are threatening the sustainability of intensive agriculture in the North China Plain (NCP). This study examined the possibility of replacing the conventional system (Con.W/M) of winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.), with an optimized double cropping system (Opt.W/M), a 2-year system (winter wheat/summer maize-spring maize, W/M-M), and a monoculture system (spring maize, M) based on optimal water and N management strategies. From 2004 to 2010, a long-term field experiment conducted in the NCP showed that although >70 mm of irrigation water can be saved with Opt.W/M compared with Con.W/M, annual net groundwater use under Opt.W/M was still 250 mm, 65-90% of which was consumed during the winter wheat season. When wheat production was decreased, 35% and 61% of irrigation water could be reduced in W/M-M and M compared to Con.W/M, respectively. As a result, annual groundwater use was decreased to 190 mm in W/M-M and 94 mm in M. Meanwhile, the N fertilizer rate was reduced 59% and 72% in W/M-M and M compared to Con.W/M, respectively. There were no significant differences in net economic returns between Con.W/M and W/M-M across the 6-year period. In the 6 years, no significant economic loss was observed between Con.W/M and M except in the 2008-2010 rotation. The W/M-M and M systems showed great potential to reduce water and N application and achieve groundwater use balance, and thus should be considered for economic and sustainable agricultural development in the NCP.