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301.
芜湖市生态旅游资源类型与发展模式探讨 总被引:1,自引:0,他引:1
近年来,生态旅游高速发展,成为旅游市场发展的主流.为了能使芜湖市的旅游业稳健地发展,走可持续发展道路。在大量调查数据的基础上,利用层次分析法和特尔菲法对芜湖市的生态旅游资源、开发条件和效益功能进行定量分析。总结芜湖市生态旅游资源的特征:发展潜力大;品位低,特色不突出;开发程度低,规模小;经济环境较好,通达性强。由此提出芜湖市的生态旅游发展应该是,不同区域采用相应的生态旅游发展模式。北部为自然和文化生态旅游相结合的模式;东部发展乡村生态旅游发展模式;西部发展文化生态旅游模式;南部发展自然生态旅游模式。在此基础上预测芜湖市旅游发展前景,对芜湖市生态旅游的发展提出了一些建议。 相似文献
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Heather E. Lintz Bruce McCuneAndrew N. Gray Katherine A. McCulloh 《Ecological modelling》2011,222(3):427-436
Ecological thresholds are abrupt changes of ecological state. While an ecological threshold is a widely accepted concept, most empirical methods detect them in time or across geographic space. Although useful, these approaches do not quantify the direct drivers of threshold response. Causal understanding of thresholds detected empirically requires their investigation in a multi-factor domain containing the direct drivers (often referred to as state space). Here, we present an approach to quantify thresholds from response surfaces modeled empirically in state space. We present two indices of shape attributes measured from response surfaces. The response surfaces are built using a regression method in state space. The indices are threshold strength (T) and diagonality (D). We use 48 simulated response surfaces of different shapes to test the efficacy of the indices in 3D. Our results show that T is sensitive to the steepness of the transition from one state to the next, with various forms of abrupt, centralized thresholds yielding the highest values among the simulated surfaces. D represents the orientation of the response surface or the simultaneous influence of more than one predictor in eliciting the response gradient. Strongly diagonal surfaces have the most diagonal surface area demonstrated by sharply undulating diagonal surfaces. Given that the success of T and D requires a regression method to accurately capture any shape of complex data structure, we also test the accuracy of empirical regression methods known to be tractable with complex data. We test classification and regression trees (CART), Random Forest, and non-parametric multiplicative regression (NPMR) for binary and continuous responses. We use the 48 simulated response surfaces to test the methods, and we find that prediction accuracy depends on both the T and D of the simulated data for each method. We choose the most accurate method among those we test for capturing any shape of response surface from real data, NPMR. Finally, we use NPMR to build response surfaces and quantify T and D from real ecological data sets. We demonstrate how measuring threshold strength and diagonality from multi-factor response surfaces can advance ecology. 相似文献
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Deepwater hydrocarbon reserves play an important role in the global energy industry. The safety issue which is associated with deepwater well control is one of the most crucial aspects during the well design and construction in a drilling scenario. Limited by the narrow drilling window and the long but small choke line, accurate prediction of the wellbore pressure is required to ensure a successful well control operation in deepwater. This paper focuses on the deepwater Driller's Method, developing an advanced simulator to predict the standpipe and choke pressures in deepwater horizontal well killing on the basis of “dynamic” bottom hole pressure. In order to improve the precision of the simulator, circulation temperature, gas expansion and choke line friction loss have been considered in the model. According to the data of a planned horizontal well X-2, the simulation and analysis of the behaviors of the standpipe and choke pressures during the deepwater Driller's Method well killing operation were performed with the proposed simulator. For further understanding the characteristics of the deepwater Driller's Method, it investigated the influence of some engineering parameters on the surface pressures, including seawater depth, horizontal section length, gas kick volume and killing rate. The results demonstrate that the standpipe pressure increases with seawater depth and killing rate; the peak choke pressure increases with seawater depth and gas kick volume; and the horizontal section length has a little impact on the standpipe and choke pressures. In addition, the application of the well killing case in BY-3 well, which is located in the South China Sea, has proved the validity of the simulator. 相似文献
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应用三维空气质量模型(Model-3/CMAQ)和积分过程速率(IPR)分析工具对2017年7月22~31日夏季4次台风持续影响下中山市7月首次出现的持续6d的O3污染事件进行了详细分析,识别了O3 8h浓度最大值时段主导的大气物理过程和大气化学过程,并计算了不同源、汇过程对本地O3浓度的贡献.研究结果表明,污染时段化学过程对O3的源贡献高于非污染时段,化学过程贡献增加,说明光化学反应过程更加活跃;台风带来的外来气团经过上风向高污染物排放区域时,化学过程贡献显著上升,与非经过高污染物排放区域相比,污染时段的化学过程对中山市O3源过程的浓度贡献高2.4%~6.5%;污染时段,水平输送对中山市大气O3源过程的浓度贡献在56.6%~92.6%之间.因此,污染期间强化本地排放源的管控,减少O3生成贡献的同时,结合区域气团路径分析,精准识别污染协同管控区域,上风向污染物高排放区域实施协同减排措施,实现区域联防联控. 相似文献
309.
纳氏试剂光度法测定水中氨氮的质量控制 总被引:2,自引:0,他引:2
对影响纳氏试剂光度法测定水中氨氮的有关因素进行了研究和探讨,以提高测定准确度与精密度。 相似文献
310.
湖泊由于其特殊的地理位置,较高的生产力,在碳循环中具有重要作用。作为湖泊营养元素的碳在湖泊水体中的赋存形态主要包括:碳酸盐系统(CO2,CO32-,HCO3-,H2CO3)、溶解态有机碳、生物死亡残体颗粒碳及生物体有机碳等。研究表明包括有机碳和溶解态无机碳在内的全世界湖泊总碳汇为0.077Gt/a,其中对大气的汇达到0.0532Gt/a。湖泊除从地表径流、地下水获得碳以外,还可从空气物质中获得碳。估算及测定水气界面CO2通量的方法主要有:①赖利估算法;②单侧扩散法;③同位素估算法;④涡度相关法;⑤静态箱式法。 相似文献