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排序方式: 共有70条查询结果,搜索用时 31 毫秒
31.
This paper evaluates the effects of long-range transport patterns of air masses to the regional PM profile in a megacity, Istanbul, Turkey. Five-day hourly backward trajectories were obtained by the HYSPLIT model for selected episodic events in 2008. Self Organizing Maps (SOM), a very powerful classification tool, was used to cluster these trajectories. In total, eight cluster groups were obtained. All of the clusters were evaluated with respect to inhalable particulate matter (PM10) concentrations observed in Istanbul for the arrival times of the trajectories. Istanbul is generally under the effect of trajectories in three clusters (1, 2 and 4) (52% of all pre-selected episodic events), which have higher mean concentration values than the mean value of all the samples. These clusters typically make significant PM contributions to Istanbul's air quality. PM loadings of the trajectories in these clusters were attributed to massive anthropogenic activity over all of Europe and southwestern air flow most likely carrying PM10 atmospheric particles originating from the Saharan Desert and other global dust generation regions located in the northern part of Africa.  相似文献   
32.
In this study, anaerobic treatability of diluted chicken manure (with an influent feed ratio of 1 kg of fresh chicken manure to 6 L of tap water) was investigated in a lab-scale anaerobic sludge bed (ASB) reactor inoculated with granular seed sludge. The ASB reactor was operated at ambient temperature (17–25°C) in order to avoid the need of external heating up to higher operating temperatures (e.g., up to 35°C for mesophilic digestion). Since heat requirement for raising the temperature of incoming feed for digestion is eliminated, energy recovery from anaerobic treatment of chicken manure could be realized with less operating costs. Average biogas production rates were calculated ca. 210 and 242 L per kg of organic matter removed from the ASB reactor at average hydraulic retention times (HRTs) of 13 and 8.6 days, respectively. Moreover, average chemical oxygen demand (COD) removal of ca. 89% was observed with suspended solids removal more than 97% from the effluent of the ASB reactor. Influent ammonia, on the other hand, did not indicate any free ammonia inhibition due to dilution of the raw manure while pH and alkalinity results showed stability during the study. Microbial quantification results indicated that as the number of bacterial community decreased, the amount of Archaea increased through the effective digestion volume of the ASB reactor. Moreover, the number of methanogens displayed an uptrend like archaeal community and a strong correlation (?0.645) was found between methanogenic community and volatile fatty acid (VFA) concentration especially acetate.  相似文献   
33.
In this study, a method which is environmentally sound, time and energy efficient has been used for recovery of indium from used liquid crystal display (LCD) panels. In this method, indium tin oxide (ITO) glass was crushed to micron size particles in seconds via high energy ball milling (HEBM). The parameters affecting the amount of dissolved indium such as milling time, particle size, effect time of acid solution, amount of HCl in the acid solution were tried to be optimized. The results show that by crushing ITO glass to micron size particles by HEBM, it is possible to extract higher amount of indium at room temperature than that by conventional methods using only conventional shredding machines. In this study, 86% of indium which exists in raw materials was recovered about in a very short time.  相似文献   
34.
In this study, Grey model (GM) and artificial neural network (ANN) were employed to predict suspended solids (SSeff) and chemical oxygen demand (CODeff) in the effluent from a wastewater treatment plant in industrial park of Taiwan. When constructing model or predicting, the influent quality or online monitoring parameters were adopted as the input variables. ANN was also adopted for comparison. The results indicated that the minimum MAPEs of 16.13 and 9.85% for SSeff and CODeff could be achieved using GMs when online monitoring parameters were taken as the input variables. Although a good fitness could be achieved using ANN, they required a large quantity of data. Contrarily, GM only required a small amount of data (at least four data) and the prediction results were even better than those of ANN. Therefore, GM could be applied successfully in predicting effluent when the information was not sufficient. The results also indicated that these simple online monitoring parameters could be applied on prediction of effluent quality well.  相似文献   
35.
Environmental Modeling & Assessment - Olive mill wastewater (OMW) is classified as highly pollutant-containing wastewater that must be treated to an acceptable level before being discharged...  相似文献   
36.
Duman F  Obali O  Demirezen D 《Chemosphere》2006,65(11):2145-2151
In this study, submerged aquatic plant Potamogeton lucens, corresponding sediment and water samples were seasonally collected from Lake Sapanca (Turkey) and analysed for their heavy metal contents (Pb, Cr, Cu, Mn, Ni, Zn and Cd). While heavy metals concentrations in the water samples were decreased as Zn > Cr > Ni > Pb > Mn > Cu > Cd, in sediment samples were Mn > Zn > Ni > Cu > Cr > Pb > Cd, respectively. Generally, heavy metals concentrations in the plant tissues were decreased in sequence of Mn > Zn > Cu > Ni > Cr > Pb > Cd. It was determined that Cu, Mn and Zn were actively transported to the root, where they were accumulated especially in autumn. Lower accumulation factor ratios were seen in spring than other seasons. Cd exhibited a relatively clear pattern of increasing accumulation in P. lucens with increasing sediment metal concentrations. Significant positive correlations were observed between Cr, Cu, Ni and Cd contents in sediment and Cd contents in root of P. lucens. The investigations suggested that Ni and Mn have a tendency to be accumulated in leaf especially in autumn and Cr and Cd to be accumulated in shoot especially in summer.  相似文献   
37.
This study reports the optimization of a binary dispersive liquid-liquid microextraction method for the determination of iprodione, procymidone, and chlorflurenol by gas chromatography mass spectrometry. The study was aimed at using two extraction solvents to increase the extraction efficiency of all analytes. The binary solvents recorded results higher than the mono-solvents. After examining the effects of main experimental parameters and their interactions by analysis of variance, 200 μL of binary mixture (dichloromethane and 1,2-dichloroethane), 2.5 mL of ethanol, and 15 s vortex were obtained as optimum parameters. The detection and quantification limits calculated for the analytes were found to be between 0.30–1.6 and 1.0–5.3 ng/mL, respectively. Enhancement in detection power calculated as a ratio of the binary extraction detection limit to the detection limit of direct GC-MS analysis was 105-, 214-, and 233-fold for chlorflurenol, iprodione, and procymidone, respectively. In order to check the accuracy of the developed method, recovery study was performed. Water sampled from a lake and two wastewater samples from treatment facilities were spiked at two concentrations, and the percent recovery calculated for the samples ranged between 87 and 116%. These results confirmed the suitability of the method to real samples for accurate determination of the analytes at trace levels.  相似文献   
38.
The aim of this study was to investigate the effects of curcumin (CUR) on antioxidant status, body weight (BW) gains, and some reproductive parameters in male rats exposed to subchronic doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Thirty-two rats were divided into four groups. The first group was kept as control. The second group (TCDD group) was given TCDD at a dose of 50 ng·kg?1 BW per day; the third group (CUR group) was treated with CUR at a dose of 80 mg·kg?1 BW per day. The fourth group (TCDD + CUR group) was given TCDD and CUR at the same doses simultaneously. Malondialdehyde (MDA) levels were significantly increased in the TCDD group. In addition, TCDD exposure decreased liver superoxide dismutase (SOD) activity, catalase (CAT) activities of kidney and brain, glutathione peroxidase (GSH-Px) activities of liver, kidney, and brain, and glutathione levels of liver, kidney, and heart. However, CUR treatment with TCDD exposure decreased MDA levels in all tissues and increased SOD activities of liver, kidney, and brain, CAT activity of heart, and GSH-Px activities of heart and brain. TCDD caused a decrease in BW gain, and CUR partially eliminated this effect of TCDD. In addition, while reproductive organ weights, sperm concentration, and sperm motility tended to decrease with TCDD exposure, these effects tended to be close to normal levels by CUR treatment. In conclusion, CUR was seen to be effective in the treatment and prevention of toxicity induced by subchronic TCDD exposure.  相似文献   
39.
In this study, we investigated the levels of vitamins A, E, and C in serum and liver, and malondialdehyde (MDA) were followed by long-term administration of some nitrosamines. Sprague-Dawley rats were divided into four groups. N-Nitrosodiethylamine (NDEA), 1-Nitrosopiperidine (NPip), and N-Nitrosopyrrolidine (NPyr) were administered 200 ppb, orally with water for 30 consecutive days to experimental groups. Animals were decapitated at 3rd, 7th, 15th, and 30th days of the administrations. Significant increases were observed in MDA levels treated with nitrosamines at all times. Serum MDA levels were found to be significantly higher in NDEA-treated animals than in control and other groups at 30th day. Liver MDA levels were highly increased in NPyr-treated group. Significant decreases were observed in the levels of vitamins A, E, and C in rats treated with nitrosamines at all times. There were also significantly negative correlations at present changes among the serum or liver MDA levels and vitamin A, E, and C levels in all nitrosamines-treated groups. These findings demonstrate that exposure at low levels of nitrosamines decreased vitamin A, E, and C levels while it attributed lipid peroxidation. Therefore, maintaining an adequate level of antioxidant vitamins in serum and liver may be necessary for the prevention or protection of long-term nitrosamine exposures.  相似文献   
40.
Abstact Aboveground biomass, aboveground litterfall, and leaf litter decomposition of five indigenous tree stands (pure stands ofPinus brutia,Pinus nigra,Cedrus libani,Juniperus excelsa, and a mixed stand ofAbies cilicica,P. nigra, andC. libani) were measured in an eastern Mediterranean evergreen needleleaf forest of Turkey. Measurements were converted to regional scale estimates of carbon (C) stocks and fluxes of forest ecosystems, based on general non-site-specific allometric relationships. Mean C stock of the conifer forests was estimated as 97.8± 79 Mg C ha−1consisting of 83.0 ± 67 Mg C ha−1in the aboveground and 14.8 ± 12 Mg C ha−1in the belowground biomass. The forest stands had mean soil organic carbon (SOC) and nitrogen (SON) stocks of 172.0 ± 25.7 Mg C ha−1and 9.2 ± 1.2 Mg N ha−1, respectively. Mean total monthly litterfall was 376.2± 191.3 kg C ha−1, ranging from 641 ± 385 kg C ha−1forPinus brutiato 286 ± 82 kg C ha−1forCedrus libani. Decomposition rate constants (k) for pine needles were 0.0016 forCedrus libani, 0.0009 forPinus nigra, 0.0006 for the mixed stand, and 0.0005 day−1forPinus brutiaand Juniperus excelsa. Estimation of components of the C budgets revealed that the forest ecosystems were net C sinks, with a mean sequestration rate of 2.0 ± 1.1 Mg C ha−1 yr−1ranging from 3.2 ± 2 Mg C ha−1forPinus brutiato 1.6 ± 0.6 Mg C ha−1forCedrus libani. Mean net ecosystem productivity (NEP) resulted in sequestration of 98.4 ± 54.1 Gg CO2 yr−1from the atmosphere when extrapolated for the entire study area of 134.2 km2(Gg = 109 g). The quantitative C data from the study revealed the significance of the conifer Mediterranean forests as C sinks  相似文献   
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