基于统计方法的辽东湾沉积物中多环芳烃来源特征分析

为研究辽东湾表层沉积物中多环芳烃(PAHs)的来源特征,2014年5月采集了20个辽东湾海域表层沉积物样品,并利用气相色谱质谱联用仪对优先控制的16种PAHs进行测定,采用聚类分析、主成分分析-多元线性回归分析、异构体比值3种统计方法对辽东湾表层沉积物中PAHs来源特征进行了研究。结果表明,辽东湾表层沉积物中PAHs含量范围88.5~199.3 ng·g-1,平均值为(126.3±35.3)ng·g-1,其中,萘、菲和荧蒽是PAHs优势组分。通过统计分析结果表明,辽东湾北部表层沉积物中PAHs含量低于西南部,沉积物中PAHs的来源包括石油燃烧来源、煤炭、木材等生物质燃烧来源和石油来源,其中燃烧来源是主要来源,煤炭、木材等生物质燃烧来源占49.9%,石油燃烧来源和石油来源占50.1%。     

Are we planning for sustainable disaster recovery? Evaluating recovery plans after the Wenchuan earthquake

This article examines local recovery plans that were created in response to the Wenchuan earthquake and then suggests ways that planners can better apply the concept of sustainability to the recovery process. We utilize a plan evaluation protocol to analyze 16 recovery plans in counties and towns that were severely affected by the earthquake. We also conducted semi-structured interviews with public officials and planners, with the qualitative data gleaned from these interviews being used to supplement the plan quality assessment. The results reveal that local recovery plans do not appear to have incorporated sufficiently the concepts of sustainability. We conclude the paper with the following recommendations: emphasizing sustainability as a policy priority during vision and goal development; developing solid databases and planning techniques; designing a diversified set of regulatory- and incentive-based policy tools suitable for local governments; enhancing social and institutional learning; and further integrating multi-level and interagency governmental units.     

舰船电子设备振动试验条件的分析和对比

对GJB 4.7-83《舰船电子设备环境试验振动试验》与GJB 150-16A-2009《军用装备实验室环境试验方法第16部分:振动试验》(A2.2.8舰船)进行了详尽的分析和对比,并结合国外标准及经验,提出了耐振试验危险频率及其振动量级的选取方法。     

北斗授时原理及终端性能检测技术

根据目前主流的北斗授时型产品应用技术,对北斗单向授时、双向授时的原理进行了介绍,提出了北斗授时终端检测检测系统的设计思路,并对北斗授时终端的基本性能指标的测试方法和评估方法进行了描述。     

Comparative experiment on treating digested piggery wastewater with a biofilm MBR and conventional MBR: simultaneous removal of nitrogen and antibiotics

A biofilm membrane bioreactor (BF-MBR) and a conventional membrane bioreactor (MBR) were parallelly operated for treating digested piggery wastewater. The removal performance of COD, TN, NH₄ ⁺-N, TP as well as antibiotics were simultaneously studied when the hydraulic retention time (HRT) was gradually shortened from 9 d to 1 d and when the ratio of influent COD to TN was changed. The results showed that the effluent quality in both reactors was poor and unstable at an influent COD/TN ratio of 1.0±0.2. The effluent quality was significantly improved as the influent COD/TN ratio was increased to 2.3±0.5. The averaged removal rates of COD, NH₄ ⁺-N, TN and TP were 92.1%, 97.1%, 35.6% and 54.2%, respectively, in the BF-MBR, significantly higher than the corresponding values of 91.7%, 90.9%, 17.4% and 31.9% in the MBR. Analysis of 11 typical veterinary antibiotics (from the tetracycline, sulfonamide, quinolone, and macrolide families) revealed that the BF-MBR removed more antibiotics than the MBR. Although the antibiotics removal decreased with a shortened HRT, high antibiotics removals of 86.8%, 80.2% and 45.3% were observed in the BF-MBR at HRTof 5–4 d, 3–2 d and 1 d, respectively, while the corresponding values were only 83.8%, 57.0% and 25.5% in the MBR. Moreover, the BF-MBR showed a 15% higher retention rate of antibiotics and consumed 40% less alkalinity than the MBR. Results above suggest that the BF-MBR was more suitable for digested piggery wastewater treatment.

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Cancer risk from gaseous carbonyl compounds in indoor environment generated from household coal combustion in Xuanwei,China

Airborne carbonyls were characterized from emitted indoor coal combustion. Samples were collected in Xuanwei (Yunnan Province), a region in China with a high rate of lung cancer. Eleven of 19 types of samples (58%) demonstrated formaldehyde concentrations higher than the World Health Organization exposure limit (a 30-min average of 100 μg m^?3). Different positive significant correlations between glyoxal/methylglyoxal and formaldehyde/acetaldehyde concentrations were observed, suggesting possible different characteristics in emissions between two pairs of carbonyl compounds. A sample in the highest inhalation risk shows 29.2 times higher risk than the lowest sample, suggesting different coal sampling locations could contribute to the variation of inhalation risk. Inhabitants in Xuanwei also tend to spend more time cooking and more days per year indoors than the national average. The calculated cancer risk ranged from 2.2–63 × 10^?5, which shows 13 types of samples at high-risk level. Cumulative effect in combination with different carbonyls could have contributed to the additive actual inhalation cancer risk. There is a need to explicitly address the health effects of environmentally relevant doses, considering life-long exposure in indoor dwellings.     

Changes of foraging patch selection and utilization by a giant panda after bamboo flowering

Environmental Science and Pollution Research - The bamboo flowering leads to the habitat fragmentation and food quality decline of a giant panda. Few empirical research has been conducted about the...     

Role of illumination intensity in microcystin development using Microcystis aeruginosa as the model algae

Environmental Science and Pollution Research - Microcystis aeruginosa (M. aeruginosa) is one of the most common genera of cyanobacteria in algal blooms. In the present work, the impact of the...     

长三角城市群“空间流”网络结构特征——基于公路运输、火车客运及百度指数的综合分析

信息技术的应用与社会信息技术的传输,使大量的要素(人流、物流、信息流)在城市群空间内集聚与扩散,加密城市群空间内城市联系。在基于公路运输、普通列车、高速列车以及百度指数4个要素的综合分析基础上,对长三角城市群"空间流"网络结构特征进行探析。研究结果表明:(1)长三角城市群区域内城市联系虽具备了网络化规模,但城市间的联系不均衡,以上海、南京、杭州等城市为多中心的协调网络发展格局特征明显;(2)长三角城市群16个核心城市"空间流"特征呈现三角形网络结构,其三角形的顶角分别由上海(沪)、南京(宁)与杭州(杭)3个核心节点城市构成。在空间结构内部,形成若干次级城市网络连线;在空间分布上,北翼网络化程度较高于南翼线性联系程度,区域联系强度以"沪—宁"、"沪—杭"沿线向两侧递减;(3)上海、南京、杭州、苏州、无锡5个核心城市排名处于网络中心的前列,扬州、南通、泰州、舟山等周边城市相对靠后,这与区域经济发展过程的"吸虹效应"有关,随着区域经济一体化程度的加深,中心城市会向周边地区提供服务与经济辐射,完善整个长三角城市群网络体系。     

围垦后南汇东滩海三棱藨草的空间分布及其影响因子研究

2015年9月~10月期间对2012年底围垦后南汇嘴区域的海三棱藨草(Scirpus mariqueter)湿地系统进行了调研,运用主成分分析、典范对应分析(canonical correspondence analysis,CCA)方法,基于101个样地土壤的有机碳、总磷、总氮、硝酸盐氮、亚硝酸盐氮、氨氮、正磷酸盐、pH、含水率、粒径、盐度、滩涂高程等12个环境因子数据,探讨了围垦后海三棱藨草空间分布的关键影响因子。结果表明:海三棱藨草的分布与滩涂高程具有显著正相关(P0.05),海三棱藨草群落主要分布在南汇滩涂2.5~3.4 m高程范围内;海三棱藨草的密度、盖度与盐度呈显著正相关(P0.05)。结论认为滩涂高程和土壤盐度是影响海三棱藨草分布的主要环境因子。未来需要结合围垦后的水动力变化过程数值模拟,对海三棱藨草生态系统高时空分辨率的响应过程及机制进行研究,以进一步确立海三棱藨草对围垦工程响应的关键阈值。研究对围垦工程后的滨海湿地植被恢复及滩涂生态修复具有参考意义。