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91.
运用Pearson相关性分析,变量重要性评分和随机森林方法构建了溶解氧(DO)实时预测模型,并以深圳湾为例采用浮标资料预测1,3,6和12h的溶解氧.模型预测结果表明,模型最优的输入条件为pH值,水温,叶绿素a,氧化还原电位和蓝绿藻5个水质指标,1h预报的相关系数在0.9以上,6h预报结果一定程度上可以满足工程要求,但对低溶解氧事件的预报必须在3h以内. 相似文献
92.
细菌等致病微生物可通过空气、水、土壤、食物等途径在自然界中传播,易对人体造成诸如肺结核、淋病、鼠疫等健康风险。目前广泛使用的灭菌方式包括紫外线、臭氧、氯气、电荷等物理或化学方法,其中电荷杀菌因具有无组织毒性的优点被广泛使用。研究表明:有机阳离子型电荷杀菌材料相比传统的金属离子杀菌材料具有抗菌效能优异、不产生耐药性、生物安全性高等优点,其杀菌性能受分子大小、烷基链、反离子类型、电荷密度等因素影响。本文系统综述了目前有机阳离子型电荷杀菌材料的类型、结构特征、杀菌性能及影响因素,抗菌机理及应用现状,分析了其存在的问题和发展方向,为有机阳离子型电荷杀菌材料的后续研究和应用提供一定的借鉴和指导。 相似文献
93.
94.
Faranak Hadi Amir Mousavi Kambiz Akbari Noghabi Hadi Ghaderi Tabar Ali Hatef Salmanian 《Journal of environmental science and health. Part. B》2013,48(3):208-213
Thirty bacterial strains with various abilities to utilize glyphosate as the sole phosphorus source were isolated from farm soils using the glyphosate enrichment cultivation technique. Among them, a strain showing a remarkable glyphosate-degrading activity was identified by biochemical features and 16S rRNA sequence analysis as Ochrobactrum sp. (GDOS). Herbicide (3 mM) degradation was induced by phosphate starvation, and was completed within 60 h. Aminomethylphosphonic acid was detected in the exhausted medium, suggesting glyphosate oxidoreductase as the enzyme responsible for herbicide breakdown. As it grew even in the presence of glyphosate concentrations as high as 200 mM, Ochrobactrum sp. could be used for bioremediation purposes and treatment of heavily contaminated soils. 相似文献
95.
Herranz M Romero LM Idoeta R Olondo C Valiño F Legarda F 《Journal of environmental radioactivity》2011,102(11):987-994
In this paper the inventory of 90Sr in 34 points distributed along the Spanish peninsular territory is presented. Obtained values range between 173 Bq/m2 and 2047 Bq/m2. From these data set and those 137Cs data obtained in a previous work the 137Cs/90Sr activity ratio has been established, laying this value between 0.9 and 3.6. Also the migration depth of both radionuclides has been analysed obtaining for 137Cs an average value 57% lower than that obtained for 90Sr.Additionally, this paper presents the results obtained in 11 sampling points in which the activity vertical profile has been measured. These profiles have been analysed to state the behaviour of strontium in soils and after, by using a convective-diffusive model, the parameters of the model which governs the vertical migration of 90Sr in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) have been evaluated. Mean values obtained are 0.20 cm/year and 3.67 cm2/year, respectively. 相似文献
96.
Ute Rita Thorenz Jaroslava Sobocka 《Environmental pollution (Barking, Essex : 1987)》2010,158(6):2208-2217
We modified an analytical method to determine polybrominated diphenyl ethers (PBDEs) in urban soils of Bratislava (Slovakia). Gel permeation chromatography (GPC) introduced as a clean-up step for soil extracts substantially reduced matrix enhancements when PBDEs were measured with gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS). The resulting method proved to be accurate, precise, and showed low detection limits. The sum of 15 PBDE concentrations in surface horizons of Bratislava soils ranged from 87 to 627 pg g−1. PBDE concentrations were mostly higher in surface than deeper horizons probably because of atmospheric deposition and lack of substantial vertical transport. Lower brominated PBDEs undergo more soil-atmosphere exchanges or are more scavenged and transferred with litter fall to the soil organic matter than higher brominated ones as suggested by the correlation between lower brominated PBDEs and soil organic C (Corg) concentrations. 相似文献
97.
Contamination episodes in soils require interventions to attenuate their impact. These actions are often based on the addition of materials to increase contaminant retention in the soil and to dilute the contaminant concentration. Here, non-hazardous wastes (such as sugar foam, fly ash and a material produced by the zeolitization of fly ash) and silicates (including bentonites) were tested and fully characterized in the laboratory to select suitable materials for remediating metal-contaminated soils. Data from X-ray fluorescence (XRF), N2 adsorption/desorption isotherms, X-ray diffraction (XRD) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDX) analyses revealed the chemical composition, specific surface area and the phases appearing in the materials. A pH titration test allowed the calculation of their acid neutralization capacity (ANC). The metal sorption and desorption capacities of the waste materials and silicates were also estimated. Sugar foam, fly ash and the zeolitic material were the best candidate materials. Sugar foam was selected because of its high ANC (17 000 meq kg−1), and the others were selected because of their larger distribution coefficients and lower sorption reversibilities than those predicted in the contaminated soils. 相似文献
98.
The vertical flow of water through horizontal layers of soil is considered using the Method of Lines. Continuity of mass principles are used to develop the interface boundary conditions, by introducing fictitious points at the interface, and the boundary conditions are handled using explicit and iterative approximations. Both the pressure based, and the water content based forms of Richards' equation are solved using the Method of Lines. The solutions obtained are compared with some particular analytic solutions obtained from the literature, and the results show that good accuracy can be achieved. It is also shown that the water content model can handle a large discontinuity at the interface when compared against the analytical solution. This result is also confirmed against a numerical example from the literature, and was effective for relatively dry initial conditions. 相似文献
99.
张满堂 《长江流域资源与环境》1996,5(2):172-176
在分析江汉平原中低产土壤形成原因的基础上,将其分为涝渍、漏瘠和粘结三种类型,提出了五条改良利用措施:1、渔农复合,增强调蓄能力;2、抗旱治渍、协调水气;3、增肥调养,增肥地力;4、选择适当作物品种和优良耕作栽培模式;5、综合治理、系列配套。 相似文献
100.
在分析了当前饮食业排污收费现状和存在问题的基础上,提出了一种较易操作的排污费征收办法,并认为这种征收办法在实践上是可行的。 相似文献