排序方式： 共有23条查询结果，搜索用时 359 毫秒
1.
2.
3.
能源消费是人类活动影响全球气候变化的主要行为之一,对能源消费导致的碳足迹进行研究具有重要意义。本文首先应用能源消费碳足迹的相关概念和方法,计算得到了甘肃省1990年-2009年的总碳足迹、各能源消费类型的碳足迹、碳足迹产值和碳足迹生态压力;然后利用STIRPAT模型进行岭回归函数拟合,探讨了经济增长与碳足迹之间的定量关系,并验证了环境库兹涅茨曲线的存在性;最后通过脱钩指数分析进一步研究了经济增长与碳足迹之间的动态变化关系。结果表明:碳足迹从1990年的每人0.091 ha上升为2009年的每人0.191 ha,呈现波动上升的趋势。各能源消费类型的碳足迹构成中,煤和石油占据了绝对地位,其中又以煤所占比重最大,石油次之,天然气所起的作用甚微。碳足迹产值由1990年的1.18万元ha-1增加为2009年的2.51万元ha-1,碳足迹生态压力也从1990年的0.10上升至2009年的0.24。人口和人均GDP是驱动碳足迹增长的主要因素,且回归分析和脱钩指数分析都表明经济增长与碳足迹之间存在环境库兹涅茨曲线。 相似文献
4.
5.
本研究基于5G技术的实时三角测绘在测绘信息中的应用案例。通过瀑布式开发模型,本文在明确使用三角控制测量法的前提下,使用5G技术及其带来的分布式计算技术和自适应组网技术,对基于5G技术的实时沉降三角测绘系统进行了开发,通过组网测试,发现该系统的测量精度与使用全站仪人工测量精度相当,且系统部署过程并未对原有的IDC核心节点增加任何设备,系统稳定性、可靠性良好,与原有IDC设施的兼容性良好。所以,本文认为,5G技术在沉降控制测量任务中具有极大的技术优势。 相似文献
6.
Qing Sun Manman Xie Liming Shi Zhuyue Zhang Yuan Lin Wenyu Shang Kaijun Wang Wei Li Jiaqi Liu Guoqiang Chu 《Journal of Paleolimnology》2013,50(3):331-344
Annually laminated sediments in Lake Xiaolongwan, northeast China, contain a suite of n-alkanes (C17–C33) with a strong odd over even carbon number predominance. Biomarker n-alkane proxies (average chain length, Paq ratio, grass/tree ratio, carbon preference index and compound-specific δ13C values) were used to reconstruct climate changes that occurred over the last millennium. Compound-specific δ13C values show large differences between the distinctive chain length groups of n-alkanes that originate from algae, aquatic macrophytes and terrestrial plants. Long-chain n-alkanes (C27–C33) are predominantly derived from leaf wax lipids in the forest. Variations in long-chain n-alkane δ13C values may mainly record water-use efficiency, inasmuch as the contribution from C4 plants is negligible in the Lake Xiaolongwan catchment. Short- and middle-chain n-alkanes are mainly from algae and aquatic plants. They are strongly depleted in 13C. This feature may be linked to a methane-derived, negative δ13C pool and lake overturn, which regulates dinoflagellate blooms. Parallel fluctuations are observed in δ13C27–31 values, Paq, and the grass/tree ratio throughout the record. Variations in δ13C27–31 values and Paq are in agreement with historical documents on summer and winter climate conditions. They support earlier suggestions that δ13C values in the long-chain n-alkanes and Paq may be useful indicators of effective precipitation or drought stress in this forested area. The δ13C27–31 index and Paq show distinct decadal variations. Periods with high δ13C27–31 values and a low Paq index correspond with the warm phases of the Pacific Decadal Oscillation (PDO). Values are reversed during PDO cool phases. At the decadal timescale, summer monsoon rainfall in northeast China over the last millennium may have been regulated mainly by the PDO. 相似文献
7.
对历届广交会的统计数据以及第109届广交会共2万多家国内参展企业的数据资料进行整理和分析,运用数理统计、地理集中指数( Index of Concentration)、吸引半径指数(Attractiveness Radius)、相关性分析等量化方法,从空间分析角度研究广交会吸引国内各地区、各行业企业参展的吸引力空间分布结构以及分布差异.结果表明:广交会对国内参展商的吸引力在空间上已经形成了广泛的覆盖;相同等级分布区(带)的省份(直辖市、自治区)表现出明显的空间连续性,不同等级的分布区(带)则呈现较显著的从 相似文献
8.
杭州城市旅游品牌的演化机理及优化 总被引：1，自引：0，他引：1
基于来杭游客的旅游博客分析,探究杭州旅游品牌塑造现状,分析杭州城市旅游品牌演化过程及各阶段特征,认为1983年前,杭州城市旅游品牌处于自然生成阶段(“人间天堂时代”),1983-2000年处于引导生成阶段(“天堂城市时代”),2001年起,进入培育塑造阶段(“品质休闲时代”);旅游资源开发、市场需求变化、政策规划引导、旅游设施与交通建设、旅游产业结构升级等是杭州城市旅游品牌演化的动力要素。探讨了各动力要素的运行关系,提出了强化“休闲之都”形象建设、加强旅游品牌整合和系统建设、树立“顾客满意”理念,提升旅游品牌忠诚度等优化措施。 相似文献
9.
10.
Pengbao Wu Aijing Yin Xiaohui Yang Huan Zhang Manman Fan Chao Gao 《Environmental Earth Sciences》2017,76(21):745
Heavy metal contamination is of great concern in rapidly urbanizing areas. A basin-basis study on the impacts of urbanization on the heavy metal contamination in surface sediments from the Qinhuai River, Eastern China, was conducted, focusing on the spatial variation and source appointments. All of the sampling sites can be divided into three groups based on the hierarchical cluster analysis (HCA) results, which correspond well to the pollution levels of the studied heavy metals in the sediments of the rural, suburban, and urban sections of the Qinhuai River. The relationship between the heavy metal and the Al/Si ratio of sediments varied distinctly with the metal species and urbanization degree of the river sections. Correlation analysis and HCA highlighted that zinc appeared to be a fairly efficient geochemical signature of urban-related heavy metal contamination. The contributions derived from urban activities ranged from 35.9% for Ni to 96.1% for Cu, as estimated by a multilinear regression of the absolute principal component score method (MLR-ACPS). Agricultural activities had a clear impact on As, Pb, and Cu contamination of the sediment. Lithologic sources contributed a significant portion of Ni, Cr, and As to the sediment. 相似文献