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261.
王谋 《气候变化研究进展》2018,14(3):303-309
基于1990—2015年世界前20个排放大国碳排放量和国内生产总值(GDP)的时间序列数据,采用协整分析、格兰杰因果检验,对主要排放大国碳排放与经济增长之间的关系进行了实证分析。通过协整分析得出大多数国家的碳排放量与经济增长之间存在长期均衡关系;碳排放量和GDP的格兰杰检验结果显示,大多数世界排放大国碳排放与经济增长之间存在单向因果关系。发达国家主要表现为经济增长是碳排放的格兰杰原因,发展中国家则主要表现为碳排放是经济增长的格兰杰原因。研究结果反映了发达国家和发展中国家在碳减排问题上的阶段性特征,碳减排对发展中国家经济发展的负面影响明显大于发达国家。基于格兰杰因果分析结果,国际气候治理进程中关于要求发展中国家现阶段提出大幅减排目标的诉求不符合发展中国家发展阶段特征,可能影响发展中国家经济发展的正常秩序和规律。发达国家基于历史排放责任、发展阶段和能力,都应该带头开展减排行动,并帮助发展中国家实现转型、升级发展,降低经济发展对碳排放的依赖。国际气候治理需要根据并考虑不同国家的发展需求和特征,形成国际合作制度安排,实现社会经济发展与全球气候治理的协同。 相似文献
262.
当前法学教育总体脱离实践,目标定位模糊,专业评价标准偏低,潜伏着被法治事业边缘化、被普法教育和法律应用教育同化的危机。法学教育亟需通过与司法考试接轨,实现两个转变———由抽象传授理论转为培养综合实践能力,由数量扩张转为质量提高———以满足依法治国实践的需要,开辟自身发展的空间。 相似文献
263.
贵州草海湿地对于气候调节、生物多样性研究等方面具有极其重要的作用。利用贵州省威宁国家基准气候站50a降雨量资料,采用数理线性回归,Man-Kendall检验法、最小平方法对降水量进行分析、预测,结果表明:年代际上,草海湿地降水量近50a来呈减少趋势,趋势递减率为-12.24mm/10a,减少趋势不明显。季节上,春季、夏季降水量呈增加趋势,趋势率分别为1.37mm/10a、6.15mm/10a。秋季和冬季降水量呈减少趋势,其中秋季减少趋势较为明显。趋势率为-17.86mm/10a。通过Man-Kendall参数趋势检验对近50a降水量进行趋势突变检验,Z值为-0.788,其绝对值小于1.28,未通过0.9的信度检验,说明降水量呈减少趋势,减少趋势不明显,与数理统计结果相吻合。Man-Kendall非参数突变检验近50a的降水量在1986年、1997年、2012年均存在突变。2019~2048年30a间草海湿地降水量呈现增加趋势。 相似文献
264.
Cores taken at Burrinjuck Reservoir in southeastern New South Wales have been dated using the first appearance of 137Cs, charcoal/bushfire correlations, and annual grass pollen peaks. None of the main 210Pb dating models reproduced the ‘known’ chronology. Correlation analysis shows no significant relationship between original 210Pb (unsupp.) concentration and grain-size, sedimentation rate or loss on ignition. Differences in sediment source may explain the variations in 210Pb. A simple provenance model has been used to interpret the ratio of original 210Pb (unsupp.)/226Ra as a tracer of topsoils and subsoils. High ratios in the reservoir sediments probably indicate eroded topsoils and low ratios eroded subsoils. 相似文献
265.
Examination of spatial variability of streamflow in headwater areas can provide important insight about factors that influence hillslope hydrology. Detailed observations of variations in stream channel input, based on a tracer experiment, indicate that topography alone cannot explain flow variability. However, determination of changes in channel input on a small spatial scale can provide valuable clues to factors, such as structural geology that control subsurface flows. 相似文献
266.
S. P. Singh 《Geotechnical and Geological Engineering》1996,14(1):41-50
Summary A variety of overbreak control techniques are used during excavation with the drill and blast system. Tracer blasting is used in Canadian underground mines to minimize blast damage and involves placing a low-strength detonating cord along the length of a blast hole prior to charging with ammonium nitrate-fuel oil (ANFO). The results of tracer blasting are not always consistent and its mechanism is only hazily comprehended. In the absence of a clearly defined mechanism, it is difficult to analyse the results of tracer blasting and to identify the factors responsible for the inconsistency of results.A series of bench blasts and pipe tests were carried out to investigate the mechanism of tracer blasting. The evidence indicated partial deflagration and desensitization of ANFO, thus reducing the total available explosive energy. The rock mass surrounding the traced blasthole experienced a low level of ground vibrations. As a result of the continuous side initiation of ANFO, energy partitioning was more in favour of gas energy. A mechanism of tracer blasting has been proposed and the factors responsible for the inconsistency of the results have been identified in this paper. 相似文献
267.
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269.
Robin E. Nimmer James L. Osiensky Andrew M. Binley Kenneth F. Sprenke Barbara C. Williams 《Hydrogeology Journal》2007,15(5):877-890
Electrical resistance tomography (ERT) was used to monitor a conductive plume dilution experiment that was conducted in fractured basalt in order to assess its applications in this type of fractured-rock environment. Tap water was injected into an injection well for 34 days to dilute a pre-existing potassium chloride (KCl) plume at a site in Idaho, USA. No further fluids were introduced artificially during a 62-day monitoring period. Both surface ERT and cross-borehole ERT were used to monitor dilution and displacement of the plume. A square grid of land-surface electrodes was used with the surface ERT. Three-dimensional images of surface ERT delineated areas of increased and decreased resistivities. Increasing resistivities are attributed to dilution/displacement of the KCl solution by tap-water invasion or the influx of seasonal recharge. Decreasing resistivities resulted from redistribution of residual KCl solution. Cross-borehole ERT was conducted between the injection well and each of seven surrounding monitoring wells. Polar plots of the injection-well resistivity data in the direction of each monitoring well delineate specific locations where tap water seeped from the injection well via preferential flow paths determined by time-dependent resistivity increases. Monitoring-well data indicate locations of clustered and isolated regions of resistivity changes. 相似文献
270.
Glacial meltwater streams in the McMurdo Dry Valleys, Antarctica exhibit daily cycles in temperature with maxima frequently reaching 10–15 °C, often 10 °C above air temperatures. Hydrologic and biogeochemical processes occurring in these streams and their hyporheic zones strongly influence the flux of water, solutes, and sediment to the ice-covered lakes on the valley bottoms. The purpose of this study was to identify the dominant processes controlling water temperature in these polar desert streams and to investigate in particular the role of hyporheic exchange. In order to do this, we analyzed stream temperature patterns on basin-wide, longitudinal, and reach scales. In the basin-wide study, we examined stream temperature monitoring data for seven streams in the Lake Fryxell Basin. For the longitudinal study, we measured temperatures at seven sites along a 5-km length of Von Guerard Stream. 相似文献