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31.
长江口及邻近海域春夏季有色溶解有机物时空分布特征及主要影响因素 总被引:1,自引:0,他引:1
利用三维荧光光谱(EEMs)-平行因子(PARAFAC)分析技术对长江口及邻近海域春季(2015年3月)和夏季(2015年7月)有色溶解有机物(CDOM)的荧光组成及分布特征进行分析.共识别出2类4个荧光组分,即类腐殖质组分C1(370/495nm)、C2(330/405 nm)、C3(365/440 nm)及类蛋白质组分C4(295/345 nm).春夏季各层4个荧光组分分布模式基本一致,从长江口到邻近海域逐渐降低.春季类腐殖质组分的高值区分布在长江口内,而类蛋白组分高值区位于南槽附近区域,表层的CDOM主要来源于陆源输入和人类活动;中层荧光强度值比表层低,受陆源影响减弱;底层荧光强度值比中层略高,是由沉积物再悬浮造成的.各荧光组分在岱山县附近海域均有一个较高值,这与岛上的居民活动有关.夏季荧光组分高值区与春季相似,各层荧光组分值接近,说明夏季研究区域水体混合较均匀.春夏季腐殖化指数(HIX)在长江口较高,而生物指数(BIX)在邻近海域较高.将4个荧光组分(C1~C4)、吸收系数(a355)与盐度(S)、溶解有机碳(DOC)、总氮(TN)、总磷(TP)、叶绿素a(Chl-a)、溶解氧(DO)做冗余分析.结果表明,4个荧光组分(C1~C4)与总氮(TN)、总磷(TP)主要受陆源输入、人类活动的影响,溶解有机碳(DOC)受陆源与海源的共同影响.本文利用三维荧光光谱-平行因子分析(EEMs-PARAFAC)技术结合多元统计方法解析了CDOM组成,清晰揭示了长江口及邻近海域CDOM的来源及主要影响因子,可为河口海域生源要素海洋生物地球化学研究提供有益的补充. 相似文献
32.
同源地人工湖水体和底泥中有机物组成及有机结构的分析研究 总被引:1,自引:0,他引:1
采用XAD-8大孔吸附树脂对水体和底泥中的有机物进行组分分离,并通过傅里叶变换红外光谱(FTIR)、紫外-可见光谱(UV-Vis)和三维荧光光谱(3DEEMs)对自然水体和底泥中的疏水酸(腐殖酸、富里酸)、疏水碱、疏水中性物质和亲水物质进行表征和对比.结果表明,水体中有机物含量:亲水物质富里酸腐殖酸疏水碱疏水中性物质,底泥中有机物的含量为:腐殖酸富里酸亲水物质疏水碱疏水中性物质.根据红外、紫外、三维荧光光谱可知底泥中有机物的芳香程度、不饱和程度及分子量大小略高于水体有机物.根据荧光指数(FI)和自生源指标(BIX)可知,底泥和水体的腐殖酸和富里酸主要来源于陆生动植物和土壤有机质,而其余物质主要源于细菌和藻类活动. 相似文献
33.
为减少风险分级排序时产生的风险结,在引入施工安全事故频率的基础上,采用单元格细化和Borda序值法改进原有的风险矩阵法。改进后的方法使得风险等级数量增加,风险结数量减少。将该方法应用于脚手架工程的风险因素的分级与排序,风险等级分为6级,且实现了12个因素的明确排序。 相似文献
34.
In this work we present a method for risk-informed decision-making in the physical asset management context whereby risk evaluation and cost-benefit analysis are considered in a common framework. The methodology uses quantitative risk measures to prioritize projects based on a combination of risk tolerance criteria, cost-benefit analysis and uncertainty reduction metrics. There is a need in the risk and asset management literature for a unified framework through which quantitative risk can be evaluated against tolerability criteria and trade-off decisions can be made between risk treatment options. The methodology uses quantitative risk measures for loss of life, loss of production and loss of property. A risk matrix is used to classify risk as intolerable, As Low As Reasonably Practicable (ALARP) or broadly tolerable. Risks in the intolerable and ALARP region require risk treatment, and risk treatment options are generated. Risk reduction benefit of the treatment options is quantified, and cost-benefit analysis is performed using discounted cashflow analysis. The Analytic Hierarchy Process is used to derive weights for prioritization criteria based on decision-maker preferences. The weights, along with prioritization criteria for risk reduction, tolerance criteria and project cost, are used to prioritize projects using the Technique for Order Preference by Similarity to Ideal Solution. The usefulness of the methodology for improved decision-making is illustrated using a numerical example. 相似文献
35.
Mukdawan Sukhang Anongphan Junkuy Nicholas Buckley Fahim Mohamed 《Journal of environmental science and health. Part. B》2020,55(3):273-282
AbstractA sudden increase in serum creatinine after paraquat intoxication has been reported in several clinical studies. However, this dramatic change of creatinine may be possibly due to an interconversion of creatine-creatinine in relation to paraquat toxicity. In order to investigate the creatine-creatinine relationship, a liquid chromatography tandem mass spectrometry in combination with electrospray ionization was developed and validated for simultaneous determination of creatine and creatinine in the serum. The chromatographic separation was achieved on a Gemini® C6-Phenyl column with a gradient elution consisting of 0.1% formic acid in ultrapure water and methanol as the mobile phase. The method yielded suitable levels of specificity and selectivity, and calibration curves of creatine and creatinine in serum were linear over the concentration range of 0.5–200?µg mL?1. The limit of quantification of both compounds was 0.5?µg mL?1, and the method was accurate within the recovery range of 96.23–102.75%, indicating the robustness of the method. The method was successfully applied to toxicological samples from paraquat-intoxicated patients, and the concentrations of creatine and creatinine were quantified. High creatine concentrations in serum samples were observed which may lead to high serum creatinine despite normal kidney function as creatine is converted to creatinine in proportion to its concentration. 相似文献
36.
37.
按提供产品的类别,乡镇尺度空间由生态空间、农业空间和建设空间组成,这3部分空间共同承载着乡镇社会经济发展的重任。坚持生态保护对发展的约束与支撑功能并存的理念,建立以生态约束为前提,并与开发建设协同推进的分区指标体系、技术方法及应用模式,是生态文明战略下空间功能分区的有益探讨。以南京市六合区雄州街道为案例,借助Arc GIS空间分析工具,采用互斥性矩阵分类法,通过对生态约束、农业发展、工业发展与人居环境等建设开发适宜性的单项与综合评价的集成,构建生态、农业和建设空间布局的总体架构,实现了街镇空间功能的整合与科学定位;划分禁止建设区、限制建设区、适宜建设区和已建设区等四大类功能区,并提出各功能区的生态环境保护措施与产业发展导向,为实施区域发展与生态保护的协同推进提供了依据。 相似文献
38.
经济发达地区土地利用结构变化预测 --以江苏省江阴市为例 总被引:30,自引:1,他引:30
结构决定功能,把握土地利用结构变化的趋势,调整社会经济发展的策略。优化土地利用结构是土地可持续利用的关键。以经济发达地区江苏省江阴市为例,运用马尔柯夫链的理论与方法,构建土地利用结构转移的概率矩阵,预测江阴市2005年和2010年的土地利用结构,并分析其变化特征,以此来研究经济发达地区近期内可能的土地利用结构变化规律。模拟结果表明,经济发达地区土地利用结构变化存在着非农化趋势加快.农地数量减少加速的现象,如果为保证耕地的数量平衡,则可能导致农地内部结构极其不合理。根据研究结果,提出适当释放农地,促进经济发展;运用经济杆杠,提高非农用地利用效率;重视耕地质量,改善生态环境的政策建议。 相似文献
39.
Thomas Schwartz Christina Jungfer Stefan Heißler Frank Friedrich Werner Faubel Ursula Obst 《Chemosphere》2009,77(2):249-257
DNA-based population analysis was applied in combination with Raman spectrometry and Environmental Scanning Electron Microscopy for the characterisation of natural biofilms from sand and activated carbon filters operated for a long term at a municipal waterworks. Whereas the molecular biology polymerase chain reaction combined with denaturing gradient gel electrophoresis approach provides a deeper insight into the bacterial biofilm diversities, Raman spectrometry analyses the chemical composition of the extracellular polymer substances (EPS), microorganisms embedded in EPS as well as other substances inside biofilm (inorganic compounds and humic substances). Microscopy images the spatial distribution of biofilms on the two different filter materials. In addition, bacterial bulk water populations were compared with biofilm consortia using the molecular fingerprint technique mentioned.Population analysis demonstrated the presence of more diverse bacterial species embedded in a matrix of EPS (polysaccharides, peptides, and nucleic acids) on the sand filter materials. In contrast to this, activated carbon granules were colonised by reduced numbers of bacterial species in biofilms. Besides α-, β-, and γ-Proteobacteria, a noticeable specific colonisation with Actinobacteria was found on activated carbon particles. Here, the reduced biofilm formation came along with a decreased EPS synthesis. The taxonomy profiles of the different biofilms revealed up to 60% similarity on the same filter materials and 32% similarity of different materials. Similarity of adherent communities from filter materials and bulk water populations from the filter effluent varied between 36% and 58% in sand filters and 6–40% in granular activated carbon filters.The biofilm investigation protocols are most crucial to subsequent acquisition of knowledge on biofilm dynamics and bacterial contributions to transformation or adsorption processes in waterworks facilities. 相似文献
40.
E. L. Zheleznaya 《Russian Journal of Ecology》2009,40(1):39-43
The overgrowing of meadow-bog communities by shrubs and trees (age 5–40 years, crown closure 0.4–0.9) leads to a decrease in incident illumination. As a consequence, juvenile and generative plants disappear from D. incarnata population loci, their average ecological density decreases, and the loci enter the state of regression. The digging activity of wild boars disrupts phytocenotically closed groups of longirhizomatous herbs, thereby creating favorable conditions for seed reproduction of D. incarnata. The species begins to form population loci with a complete ontogenetic spectrum and high ecological density, eventually restoring the normal (definitive) population structure. 相似文献