中国特大城市空间形态变化的时空特征   总被引：64，自引：4，他引：60  

王新生  刘纪远  庄大方  王黎明 《地理学报》2005,60(3):392-400

基于国家资源环境数据库动态土地利用数据, 借助GIS软件支持, 分别计算了1990年和2000年中国31个特大城市平面轮廓形状的分维、紧凑度和形状指数以及城市的用地扩展类型。结果表明, 从1990年到2000年, 中国31个特大城市空间形态的总体变化趋势是, 城市用地空间扩展类型以填充类型为主, 外延类型相对较少且主要发生在发展限制较小的平原地区。总体上, 分维呈减少趋势且南方城市大于北方城市, 形状指数有减少, 城市空间形状有紧凑化趋势。综观1990年和2000年中国31个城市的分维、紧凑度和形状指数的数据, 可以看出广州、南昌、济南、成都、北京和上海等城市形状变化比较大, 而兰州、太原和唐山等城市形状变化很小。若用地扩展为填充类型, 则分维减少, 紧凑性增加, 形状指数减少;相反, 若用地扩展为外延类型, 分维增加, 紧凑性降低, 形状指数增加。  相似文献   

Quad and compact multitemporal C-band PolSAR observations for crop characterization and monitoring     

《International Journal of Applied Earth Observation and Geoinformation》2019

Monitoring crop condition using optical satellite indices has a legacy of several decades. Early warning of variances in crop production is vital in mitigating regional and global food insecurity. Adoption of optical vegetation indices for this purpose is widespread, yet cloud cover impedes the acquisition of these data. Although early research using scatterometers and aircraft hinted at the sensitivity of Synthetic Aperture Radar (SAR) responses to crop development, the implementation of satellite SAR observations in operational crop condition monitoring is limited. In the research presented here, volume-to-surface (V/S) scattering ratios derived from C-band RADARSAT-2 quad and simulated compact polarimetric (QP and CP) imagery are assessed for their potential to monitor crop growth. Both V/S ratios were strongly correlated with optical vegetation indices, including the widely adopted Normalized Difference and Soil Adjusted Vegetation Indices. The changes in the ratio of volume to surface scattering were correlated with variations in crop biomass. The results support the potential of a SAR scattering ratio for crop condition monitoring. In particular, encouraging results were reported for compact polarimetry, a mode that can be implemented to deliver broader swath coverage conducive to regional and national monitoring.  相似文献   

Effects of a generalized uncertainty principle on the MIT bag model equation of state     

Marcelo Netz-Marzola  César A. Zen Vasconcellos  Dimiter Hadjimichef 《Astronomische Nachrichten》2024,345(2-3):e240016

  相似文献   

致密碎屑岩储层裂缝和产能预测的单井建模—以XZ气田沙溪庙组为例   总被引：5，自引：0，他引：5  

匡建超  徐国盛  王允诚  胡远来  邓少云  符晓 《矿物岩石》2001,21(2):62-67

近年来，利用三维地震资料进行致密碎屑岩储层裂缝和产能的识别预测取得了一些进展，而这之中最重要也是基础的工作是单井裂缝和产能的建模工作，本文以XZ气田沙溪庙组致密储层为例，详细介绍了综合运用岩芯资料、测井资料和录井资料进行裂缝和产能单井建模的方法，为利用三维地震资料建立裂缝和产能的灰色遗传过程识别预测模式打了良好的基础。  相似文献   

川西致密砂岩气藏试井曲线特征分析   总被引：5，自引：0，他引：5  

罗金丽  靳正平 《矿物岩石》2001,21(4):65-70

川西致密砂岩气藏属于典型的致密低渗复式气藏，气藏类型及其压力恢复曲线形态复杂，其解释模型也各不相同，这给试井解释工作带来了极大的困难。结合静动态资料、压裂作业、测试工艺，应用4种储层模型、3种井模型及边界模型组合的试井解释模型，对川西致密砂岩气藏200多井层压力恢复资料进行了，并根据试井曲线特征对曲线类型进行了分类，为今后的试井解释工作提供了一种可资借鉴的解释方法和工作思路。  相似文献   

确定矿石体重的回归预测法     

王玉中 《新疆地质》1993,(3)

影响矿石体重的因素很多,如矿石的密度、湿度、物质组成的种类、含量等。确定矿石体重的传统做法——平均体重法主要考虑的是前二种属于物理方面的因素;而测重于考虑后二种属于化学方面的因素的方法——回归预测法,是确定矿石体重的另一个方法,它是依据矿石中元素的含量与矿石体重的相关关系,应用回归分析法建立一个函数关系式,利用此关系式用矿石中元素的含量来动态地确定矿石的体重。将这个方法的使用效果与平均体重法进行对比,前者比后者好。  相似文献   

热压铁基孕镶金刚石钻头的试验研究   总被引：1，自引：1，他引：0       下载免费PDF全文

李子章  邓伟  杨凯华 《探矿工程》2008,35(7):94-96

针对在坚硬致密岩石中钻进时效低和钻头使用寿命短的技术难题,分析了热压钻头的金刚石出刃与岩石研磨性等岩性之间的内在联系,认为钻头的胎体成分及其性能是关键,硬而带脆性的胎体性能有利于金刚石出刃,从而能提高钻进速度。因此,从热压金刚石钻头的胎体成分与性能研究入手,经过反复的试验研究,试制出了热压铁基孕镶金刚石钻头,取得了突破性的进展。在坚硬致密岩层中钻进,钻进时效由0.5 m左右提高到1.17 m,钻头寿命由10 m左右提高到21.31 m,解决了在坚硬致密岩层中钻进难的问题。试验研究结果说明,铁基合金是一种新型的金刚石钻头胎体材料,热压铁基孕镶人造金刚石钻头是一种新类型的金刚石钻头。  相似文献   

Refractive Focusing by Interstellar Clouds and the Rapid Polarization Angle Swing in QSO 1150＋812     

G. Cimò 《中国天文和天体物理学报》2006,6(1):1-14

A very rapid polarization position angle swing of～180°(with a time scale of～6 hours)observed at 2cm in QSO 1150+812(z=1.25)was reported by Kochenov & Gabuzda.This very rare event is difficult to explain.We found a pos- sible interpretation in the framework of a source model consisting of three polarized components,in which two compact polarized components are nearly simultaneously occulted by an interstellar cloud,with consequent focusing-defocusing effects.A spe- cific plasma-lens model is proposed which can reasonably fit the polarized flux density curve with results derived for the two lensed components.Some physical parameters of the plasma-lens and the source components are estimated.The two compact po- larized components are estimated to have brightness temperatures of～6×10~(12)K. Thus a bulk relativistic motion with a Lorentz factor less than 10 is required to meet the inverse-Compton limit.  相似文献   

基于RS和GIS的哈尔滨市城市空间扩展研究     

金明一 《测绘与空间地理信息》2016,(11)

准确掌握城市空间发展情况及过程,判别城市空间发展的趋势,为城市整体发展制订合理规划有重要的现实意义。本文选取1995~2015年间4个时段的影像数据,提取不同时间段的城市空间范围,利用GIS空间分析技术对哈尔滨市城市空间扩展情况进行监测。分析结果显示,哈尔滨城市空间较为离散,主城区面积逐年增加,年均增长保持在10%以上,2005年后增速明显加快,2015年城区范围趋于稳定。  相似文献   

GIS-based sustainable city compactness assessment using integration of MCDM,Bayes theorem and RADAR technology   总被引：1，自引：0，他引：1  

Saleh Abdullahi  Mustafa Neamah Jebur 《国际地球制图》2015,30(4):365-387

In recent decades, compact urban development and smart cities are recognised as most sustainable urban form in an effort to protect natural environment. Therefore, evaluation of existing compactness and sustainability of an area is an essential task before the real development takes place. In the literature, it is possible to see some studies on city’s compactness assessment and most of them have considered only a few aspects of compact development analysis. This paper aims to analyse urban sustainability of Kajang city (Malaysia) through a comprehensive city compactness assessment using geographical information system and radar remote sensing technology. To measure building density, a RADAR image of the study area was used to extract built-up areas with the aid of pixel-based and object-based classification schemes. Mixed land use development, urban density and intensity were the main indicators of the analysis. Finally, multicriteria decision-making and Bayes theorems were applied for overall compactness assessment. Building density analysis was validated using standard confusion matrix, which showed more than 90% accuracy. Similarly, the root-mean squared error showed 0.35 for object-based classification. The results classified the zones of the Kajang city in the range of least to most compact zones with the compactness value of 0.00273–0.0146, respectively. The results obtained in this study can help local government to improve the compactness of least compact zones to make Kajang city more sustainable. Furthermore, the results revealed that efficient public transportation and proper community facilities are the key factors to achieve sustainable urban development.  相似文献