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951.
主要介绍了地震数据断记报警软件及其相关地震数据分类处理软件,此软件一方面保证了地震监测数据的连续性,另一方面使科研人员查询地震事件波形,迅速快捷,并可对典型地震事件和震相特征进行查看,提高对一些特殊地震震相的识别,从而也提高了地震的分析水平. 相似文献
952.
S. C. Pryor R. J. Barthelmie B. Jensen N. O. Jensen L. L Srensen 《Atmospheric environment (Oxford, England : 1994)》2002,36(39-40)
Summertime nitric acid concentrations over a deciduous forest in the midwestern United States are reported, which range between 0.36 and 3.3 μg m−3. Fluxes to the forest are computed using the relaxed eddy accumulation technique and gradient methods. In accord with previous studies, the results indicate substantial uncertainties in the gradient-based calculations. The relaxed eddy accumulation (REA) derived fluxes are physically reasonable and are shown to be of similar magnitude to dry deposition estimates from gradient sampling. The REA derived mean deposition velocity is approximately 3 cm s−1, which is also comparable to growing season estimates derived by Meyers et al. for a similar deciduous forest. Occasional inverted concentration gradients and fluxes are observed but most are not statistically significant. Data are also presented that indicate substantial through canopy penetration of nitric acid. 相似文献
954.
改性累托石对镉离子吸附性能的研究 总被引:1,自引:1,他引:1
将天然累托石进行处理制备改性累托石.在静态条件下,研究了改性累托石对重金属离子Cd2 的吸附容量、等温吸附等吸附性能,同时探讨了影响吸附的因素和吸附机理.结果表明,改性累托石对Cd2 的吸附容量高.在20℃,pH=5.0~7.0、Cd2 浓度0~100 mg/L范围内,按镉与改性累托石质量比为1∶20投加改性累托石进行处理,吸附时间为90min,Cd2 去除率可达96%以上,改性累托石对Cd2 的吸附在实验浓度范围内符合符合Freundlich方程. 相似文献
955.
采用强碱性离子交换纤维对含氰废水中主要离子铜氰络合物、锌氰络合物的吸附性能进行了研究。实验结果表明:含氰废水的pH在8—11范围内,纤维材料对金属氰络合物具有良好的吸附性能;纤维对铜氰络合物、锌氰络合物的吸附速率很快,4min左右就可达吸附平衡;温度对铜氰络合物、锌氰络合物吸附影响不大,纤维的这些吸附特点对工业应用非常有利。 相似文献
956.
Clay and organic matter are considered as important parameters influencing bioavailability and ecotoxicity of metals in soils. As there exists a large variation in the type of clay and organic matter in field soils, the quantity of these variables alone may not be good indicators of metal bioavailability. To test this hypothesis, toxicity experiments with the potworm Enchytraeus albidus were conducted in artificial soils with three types of clay and seven types of organic matter, while the soil pH was kept constant. The 14d LC50 of zinc and cadmium varied from 83.0 to 1140 mg Zn/kg D.W. and from 55.2 to 704 mg Cd/kg D.W., respectively, depending on the type of clay and organic matter that were used. Simultaneous measurements of the cation exchange capacity showed that this soil parameter is a better indicator of the bioavailability as it takes into account the type of clay and organic matter as well as other adsorption phases such as metal oxyhydroxides. 相似文献
957.
模拟酸雨对森林红壤中铝的溶出及不同土层酸度变化的影响 总被引:9,自引:0,他引:9
为进一步探明酸沉降对森林红壤及生态环境的影响,模拟长沙地区降水酸度及离子组成,采用浸泡试验对两种森林红壤活性铝的释出及土壤理化性质的变化进行了研究。结果表明,模拟酸雨浸泡初期,土壤活性铝的释出量随浸泡次数的增加而增加,原始土壤pH值愈低,活性铝释出愈多;强酸度、高离子浓度(AR4)模拟酸雨对土壤中活性铝的溶出量远大于基础酸雨(AR3)及弱酸、低离子浓度酸雨(AR2)和对照酸雨(AR1)。模拟酸雨酸度愈大,对土壤pH值的影响愈明显,不同土层间,以A层土壤pH值下降最明显,B、C层土壤则下降较小。模拟酸雨模拟浸泡土壤25年后,土壤阳离子交换量均有不同程度下降,有机质含量高,原土壤阳离子交换量大的土壤下降幅度也大。 相似文献
958.
Jens Newig Nicolas W. Jager Elisa Kochskämper Edward Challies 《Journal of Environmental Policy & Planning》2019,21(3):213-227
ABSTRACTTheory on participatory and collaborative governance maintains that learning is essential to achieve good environmental outcomes. Empirical research has mostly produced individual case studies, and reliable evidence on both antecedents and environmental outcomes of learning remains sparse. Given conceptual ambiguities in the literature, we define governance-related learning in a threefold way: learning as deliberation; as knowledge- and capacity-building; and as informing environmental outputs. We develop nine propositions that explain learning through factors characterizing governance process and context, and three propositions explaining environmental outcomes of learning. We test these propositions drawing on the ‘SCAPE’ database of 307 published case studies of environmental decision-making, using multiple regression models. Results show that learning in all three modes is explained to some extent by a combination of process- and context-related factors. Most factors matter for learning, but with stark differences across the three modes of learning, thus demonstrating the relevance of this differentiated approach. Learning modes build on one another: Deliberation is seen to explain both capacity building and informed outputs, while informed outputs are also explained by capacity building. Contrary to our expectations, none of the learning variables was found to significantly affect environmental outcomes when considered alongside the process- and context-related variables. 相似文献
959.
Background: Tailgating is a common aggressive driving behavior that has been identified as one of the leading causes of rear-end crashes. Previous studies have explored the behavior of tailgating drivers and have reported effective solutions to decrease the amount or prevalence of tailgating. This paper tries to fill the research gap by focusing on understanding highway tailgating scenarios and examining the leading vehicles’ reaction using existing naturalistic driving data. Method: A total of 1,255 tailgating events were identified by using the one-second time headway threshold criterion. Four types of reactions from the leading vehicles were identified, including changing lanes, slowing down, speeding up, and making no response. A Random Forests algorithm was employed in this study to predict the leading vehicle’s reaction based on corresponding factors including driver, vehicle, and environmental variables. Results: The analysis of the tailgating scenarios and associated factors showed that male drivers were more frequently involved in tailgating events than female drivers and that tailgating was more prevalent under sunny weather and in daytime conditions. Changing lanes was the most prevalent reaction from the leading vehicle during tailgating, which accounted for more than half of the total events. The results of Random Forests showed that mean time headway, duration of tailgating, and minimum time headway were three main factors, which had the greatest impact on the leading vehicle drivers’ reaction. It was found that in 95% of the events, leading vehicles would change lanes when being tailgated for two minutes or longer. Practical Applications: Results of this study can help to better understand the behavior and decision making of drivers. This understanding can be used in designing countermeasures or assistance systems to reduce tailgating behavior and related negative safety consequences. 相似文献
960.
为实现风网实时解算、系统优化调节等关键技术,需要去除监测数据噪声,得到结构清晰、纯度较高的通风数据。利用FCM,Rloess和S-G等平滑降噪算法对300组实测风速数据进行分析处理。结果表明:FCM算法处理过程变量引起噪声较为优越,但需提前给定分类数目;窗宽参数选7时,Rloess算法去除由状态变量引起的风速异常数据最优;在窗宽选5、次数为2时,S-G算法降噪和保持数据特性最佳;结合使用FCM-Rloess或FCM-SG算法可有效处理过程变量和状态变量引起的风速异常数据。研究结果可为矿井通风的异常诊断、灾变识别等研究提供合理的基础数据。 相似文献