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441.
442.
介绍了苏州市环境污染事故应急监测系统的适用范围和基本特点,明确了领导小组、各监测小组及网络成员单位在系统中的职责,提出了系统的工作程序,建议开展应急监测能力培训,建立应急监测信息交流系统,实施例行监督检查,研制并定期更新应急监测信息管理系统,配置必要的应急监测仪器装备,加强与网络成员单位的合作,定期评审和改进应急监测系统,以保证系统的有效运行。环境污染事故应急监测实例表明,该系统在应急监测过程中发挥了良好的作用。 相似文献
443.
基于加速度研究过山车立环轨道曲线的设计方法.分别研究向心加速度恒定的立环曲线,加速度恒定的立环曲线和以欧拉螺线为基础的立环曲线.建立三种立环曲线的方程,通过数值方法进行求解,借助Matlab计算在给定初始条件和边界条件下的轨道曲线.以加速度为评判标准来分析三种曲线的优点和缺点,最终得到以加速度为基础的立环轨道曲线设计方... 相似文献
444.
445.
Heather E. Golden Elizabeth W. Boyer Michael G. Brown S. Thomas Purucker René H. Germain 《Journal of the American Water Resources Association》2009,45(4):945-962
Abstract: Nitrate‐nitrogen (NO3‐N) concentrations in stream water often respond uniquely to changes in inter‐annual conditions (e.g., biological N uptake and precipitation) in individual catchments. In this paper, we assess (1) how the spatial distribution of NO3‐N concentrations varies across a dense network of nonnested catchments and (2) how relationships between multiple landscape factors [within whole catchments and hydrologically sensitive areas (HSAs) of the catchments] and stream NO3‐N are expressed under a variety of annual conditions. Stream NO3‐N data were collected during two synoptic sampling events across >55 tributaries and two synoptic sampling periods with >11 tributaries during summer low flow periods. Sample tributaries drain mixed land cover watersheds ranging in size from 0.150 to 312 km2 and outlet directly to Cayuga Lake, New York. Changes in NO3‐N concentration ratios between each sampling event suggest a high degree of spatial heterogeneity in catchment response across the Cayuga Lake Watershed, ranging from 0.230 to 61.4. Variations in NO3‐N concentrations within each of the large synoptic sampling events were also high, ranging from 0.040 to 8.7 mg NO3‐N/l (March) and 0.090 to 15.5 mg NO3‐N/l (October). Although Pearson correlation coefficients suggest that this variability is related to multiple landscape factors during all four sampling events, partial correlations suggest percentage of row crops in the catchments as the only similar factor in March and October and catchment area as the only factor during summer low flows. Further, the strength of the relationships is typically lower in the HSAs of catchment. Advancing current understanding of such variations and relationships to landscape factors across multiple catchments – and under a variety of biogeochemical and hydrological conditions – is important, as (1) nitrate continues to be employed as an indicator of regional aquatic ecosystem health and services and (2) a unified framework approach for understanding individual catchment processes is a rapidly evolving focus for catchment‐based science and management. 相似文献
446.
Li Li Shixiao Yu Baoping Ren Ming Li Ruidong Wu Yongcheng Long 《Environmental science and pollution research international》2009,16(4):474-478
Background, aim, and scope The Yunnan snub-nosed monkey is one of the most endangered primates in the world. It is experiencing a range of ongoing threats
and the persisting effects of past disturbances. The prospects for this species are not very optimistic because habitat corridors
are severely damaged by logging, grazing, and mining. Each group of the monkeys in different areas is facing a unique variety
of threats. Based on genetic analysis, Rhinopithecus bieti should be separated into three management units for conservation, of which the Mt. Laojun management unit involves the most
endangered primates. Despite the fact that the vegetation on Mt. Laojun is in a relatively pristine state, only two groups
of monkeys, of a total of fewer than 300, survive in the area. With this paper, we aimed to address the capacity of the monkeys’
habitat at the study site and the possible reasons for the small populations.
Materials and methods Rapid ecological assessment based on a SPOT 5 image and field survey was used to simulate the vegetation of the whole area
based on reference ecological factors of the GIS system. The vegetation map of the site was thus derived from this simulation.
Based on the previous studies, the three vegetation types were identified as the suitable habitat of the monkeys. The confusion
matrix-based field GPS points were applied to analyze the precision of the habitat map. Based on the map of suitable habitat
of the monkeys, the utilization of the habitat and the carrying capacity were analyzed in the GIS.
Results The confusion matrix-based field GPS points were applied to the habitat analysis process, and it was found that the habitat
map was 81.3% precise. Then, with the current habitat map, we found that the mixed forest currently used by the monkeys is
only a very small fraction (2.65%) of the overall potential habitat of the population, while the dark conifer forest is 4.09%.
Discussion Poaching is the greatest short-term threat to this species, particularly in the southern range where local residents have
a strong tradition of hunting. Quite a few individual monkeys are still trapped accidentally due to the high density of traps.
These problems are hard to mitigate because it is difficult to enforce laws due to the extremely rugged terrain.
Conclusions The results show that there is a great ecological capacity of the area for the monkey’s survival and a great potential for
an expansion of the monkey population at the site. Based on the current population and its geographical range, it can be estimated
that the suitable habitat area defined by this study can support more monkeys, about many times the current population. Thus,
at least in the Mt. Laojun Area, poaching pressure is the main factor to be responsible for the low density of Yunnan snub-nosed
monkeys instead of habitat alteration.
Recommendations and perspectives Based on these results, some suggestions relating to conservation can be made: Focus conservation efforts on the current distribution
area of the monkeys and create a 20 km buffer zone; design a long-term plan for the suitable habitat outside the buffer zone
to set up a wildlife corridor in the long run; establish an association for the local hunters exploiting, their knowledge
on the animals to promote monkey conservation and stop poaching. Also, the map derived from the study helps managers to allocate
conservation resources more efficiently and enhances the overall outcomes of conservation measures. 相似文献
447.
好氧与厌氧氨氧化复合颗粒污泥完全自营养脱氮影响因素 总被引:4,自引:1,他引:3
采用间歇实验,考察了初始NH+4-N浓度、DO浓度和pH对颗粒污泥完全自营养脱氮的特性的影响。研究表明,在完全自营养脱氮系统中,当DO为0.6~0.8 mg/L,pH控制在7.5~7.8时,好氧氨氧化和厌氧氨氧化速率在一定范围内随NH+4-N浓度(30~150 mg/L)的增加而增加,较高的氨氮浓度能提高自营养脱氮反应速率。较高的DO有利于提高亚硝酸盐氧化速率,但会导致亚硝酸盐的积累;DO浓度过低时,好氧氨氧化过程受到抑制。NH+4浓度为36 mg/L,DO控制在0.6~0.8 mg/L的条件下,当pH值为7.8时,完全自营养脱氮的效果最佳,总氮去除速率达最大值为23.976 mg/(g MLSS·d)。 相似文献
448.
糖蜜酒精废水两相UASB处理工艺的酸化段特征 总被引:7,自引:0,他引:7
文章考察了糖蜜酒精废水二相UASB处理工艺的酸化段特征 ,试验结果表明酸化段的容积负荷达到3 0kgCOD/m3 时 ,系统仍能正常运行 ,TOC去除率在 3 5%以上 ,酸化段的SO4 2 -去除率在 70 %。糖蜜酒精废水酸化率在 50 % ,二相厌氧生物处理系统并未将产酸微生物与产甲烷微生物截然分开 ,在产酸相中仍含有一定数量的产甲烷菌。 相似文献
449.
天津市蓟县经济开发区环境影响评价与规划 总被引:3,自引:0,他引:3
以天津市蓟县经济开发区区域环境质量现状调查和评价为基础,依据环保法规和标准,预测了区域环境的承载能力及区域开发建设对环境的影响,提出削减各种不利影响的措施和控制对策。通过对规化方案的优化分析,提出出有利于区域社会、经济与环境协调发展的战略对策及规划总体方案。 相似文献
450.
The concentration of dissolved reactive phosphorus (DRP) in rivers can change intermittently within minutes depending on the weather and water discharge (Q), or activities in the watershed. Accordingly, accurate estimation of the annual DRP load requires frequent sampling or even continuous monitoring, which is laborious and cost-intensive. We present the design and laboratory evaluation of a new, robust, low-cost, low-tech device based on passive samplers (P-traps). The traps use Fe-(oxy)hydroxide coated quartz sand as an adsorbent enclosed in a vertical grid of individual cells separated from the river water by filter membranes. They are inexpensive, easy to handle, resistant to repeated desiccation and immersion and exposable for several months. They permit estimation of discharge dependent time weighted average DRP concentrations (C-Q relationships) and annual P loads of rivers characterized by highly variable DRP concentrations with a relative accuracy of +/- 3%. 相似文献