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41.
Transplanting cityscapes: the use of imagined globalization in housing commodification in Beijing 总被引：1，自引：0，他引：1
How does globalization unfold in the process of urban development? Rather than examine the impact of globalization on the city as if the former were independent of and superimposed on the latter, this paper aims to address how globalization can be imagined, pursued and exploited in the process of local growth. Through examining the emergence of Western architectural motifs in a late socialist capital, Beijing, it is shown that transplanting cityscapes is a conscious action by developers to exploit globalization and thereby overcome the constraints of local markets. By associating themselves with globalization, the development elite hope to sell the vision of the good life in the era of globalization. 相似文献
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天然气水合物储层具浅埋藏、弱固结、低渗透、高泥质、非均质等特点,钻采过程中易出现严重的出砂问题,是制约天然气水合物安全高效开采的“瓶颈”之一。现有的天然气水合物储层防砂技术主要来源于常规油气开采中常用的防砂方法,防砂精度控制和稳产增产矛盾突出。为此,本文提出了一种天然气水合物储层超声雾化防砂排水采气方法,配合挡砂介质在有效防住10 μm以上砂的同时,将水雾化成5 μm左右的小水滴产出,降低水的携砂能力并加速水气产出,进而实现连续排水产气。基于该方法搭建了简易实验模拟评价装置,进行了初步的模拟实验。实验结果表明该方法具有一定的可行性,水气可以通过雾化片的锥孔不断产出。但是由于储层砂中还存在大量直径小于雾化片锥孔直径的泥质成分,雾化装置还需针对泥质成分的存在做进一步优化,否则泥质成分将堵塞在雾化片锥孔附近降低雾化片的振荡频率,造成排水产气的中止。这些初步的工作可以为天然气水合物储层防砂增产提供新的思路。 相似文献
44.
气象数据是水文过程研究的关键要素,再分析数据的发展为资料缺乏地区的径流模拟提供了新的解决方案。为研究ERA5-Land再分析数据集在径流模拟中的适用性,本文以玛纳斯河流域肯斯瓦特水文站以上流域为研究区,选取多个评价指标对ERA5-Land降水和温度进行准确性评价,并采用经验模态分解(EOF)分析其在研究区内的分布特点。在准确性方面,ERA5-Land与实测数据具有较好相关性,降水探测率为0.96,能反映大多数的降水事件,但与实测数据相比总体偏高21.81%,气温准确性好于降水,总体拟合效果较好,最优范围为-520 ℃,在极值部分不确定性有所增加。EOF决定性模态表明研究区内降水、气温变化趋势基本一致,即易受大尺度天气系统影响。利用该数据集驱动SWAT模型在月、日尺度上对玛纳斯河流域进行径流模拟,在验证期纳什系数(NSE)分别为0.88和0.82,具有较好的模拟效果。ERA5-Land再分析数据集可为西北缺乏实测气象资料地区径流模拟提供参考。 相似文献
45.
Fulong Chen Nicola Masini Jie Liu Jiangbin You Rosa Lasaponara 《International Journal of Digital Earth》2016,9(12):1224-1241
Synthetic Aperture Radar (SAR) remote sensing is increasingly favoured in archaeological applications. However, the effectiveness of this technology for archaeological prospection has so far not been fully assessed. In this study, an integrated single-date and multi-temporal SAR data-processing chain was proposed to sharpen archaeological signs and hence their detection and monitoring. In total, 14 scenes of X-band Cosmo-SkyMed, C-band Sentinel-1 and L-band PALSAR data covering the Western Regions of the Silk Road Corridor in China were employed for two important archaeological sites including the Yumen Frontier Pass with emerging archaeological traces and Niya ruins with subsurface remains. The results pointed out that single-date satellite radar data were useful for the identification of subsurface traces buried under desert in the landscape-scale, whereas for the identification of emerging monuments, Sentinel-1 was limited by its lower spatial resolution compared to TerraSAR and PALSAR data. Multi-date products, such as interferometric coherence, the averaged radar signatures and RGB multi-temporal composites, were effective to sharpen archaeological traces as well as for change detection in Yumen Frontier Pass. This study presents a pilot assessment of satellite SAR data for the analysis and monitoring of archaeological features in the predominantly arid-sandy environmental characteristic of investigated sites. 相似文献
46.
Effects of land use change on flood characteristics in mountainous area of Daqinghe watershed, China 总被引：2，自引：0，他引：2
Land use has changed in the Daqinghe watershed during 1956–2005, and it has influenced the flood peak and volume. In order to reveal the effects of land use change on flood characteristics in Daqinghe watershed, we selected 2 sub-watersheds and used remote-sensed land use data of 1980 and 1996 to analyze changes in land use and also selected several combinations of similar rainfall events and the corresponding flood events to show how changes in land use affect floods. The forest and urban area increased and other types decreased, and flood peaks and volumes tended to decrease under similar rainfall events. To quantify the extent of change in land use affecting floods, a hydrological model incorporating the land use was established. The model combines infiltration excess and saturation excess runoff generation mechanism in each type of land use, and the simulation results agreed well with the measured flood processes in the two selected watersheds. Several floods of different return intervals were selected to be modeled under the 1980 and 1996 land use conditions. The results show that both flood peak and volume decreased under the 1996 land use condition in comparison with the 1980 land use condition in the two watersheds. Most of the flood peaks decreased <5 %, but the volume decreased to a greater extent. This result can be helpful in modifying design flood. 相似文献
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全球气候变化引起的极端降雨、洪涝灾害是导致不可移动文物受损的重要破坏因素。合成孔径雷达SAR（Synthetic Aperture Radar）具有全天时、全天候、大范围周期性对地观测的优势,是大区域水体监测的重要手段,对不可移动文物水域淹没及风险监测具有重要意义。本文利用时间序列SAR图像提出基于残差U-Net的不可移动文物水域淹没及风险监测框架。首先,基于双峰阈值分割法结合专家知识辅助进行水体样本生成,提高样本制作效率;其次,引入残差模块建立U型卷积网络,综合残差结构及U-Net的特点,缓解梯度更新时的弥散、消失等现象,通过卷积层之间累加和跳跃链接,保留多尺度的地物特征信息,以实现水体快速、高精度的语义分割;最后通过将结果与不可移动文物点位进行空间叠加分析,实现对不可移动文物水淹状况的监测。选取鄱阳湖及南昌市昌邑北垱遗址作为试验研究对象。获取了21景覆盖鄱阳湖区域不同时相Sentinel-1 SAR图像,并结合Sentinel-2光学图像进行结果分析与评价。实验结果表明：本文方法在鄱阳湖试验区对水体提取总精度优于95%,相较于FCN（Fully Convolutional Networks）与U-Net方法具有更好的精度。利用不同时相SAR图像获得时间序列水体分布范围变化图,与昌邑北垱遗址点位进行空间叠加分析,得到不可移动文物水域淹没长时间序列监测结果。实验结果表明本文提出的方法可以有效提取水体范围,对不可移动文物水域淹没及风险监测可以提供有力支撑。 相似文献
50.
提出了一种基于案例(CASE)推理的多时相SAR影像分类方法.选用北京地区2000年(4景)和2004年(3景)的多时相Radarsat-1 SAR影像及相应地理基础分类图作为数据进行实验,结果表明,该方法能得到较好的SAR影像分类结果.分类总体精度可望达到85%. 相似文献