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991.
中国省级以上开发区产业集聚的多尺度分析   总被引:1,自引:0,他引:1  
胡森林  曾刚  刘海猛  庄良 《地理科学》2021,41(3):407-415
从"区域-省域-地(市)"3个空间尺度入手,分析中国开发区产业集聚特征,结果表明:①中国开发区总体上以技术密集型为主导,装备制造、电子信息、生物医药产业优势明显.但东中西部差异巨大,技术密集型、劳动密集型、资本密集型产业分别占据地区主导地位.②开发区产业集聚度随尺度缩小而扩大,城市群、中心城市是其最重要的空间载体.同时...  相似文献   
992.
In the present study, the coal-rock organic facies of Oligocene Yacheng Formation of the marginal basin in the South China Sea were classified and divided. In addition, through the correlations of the large-scale coal-bearing basins between the epicontinental sea and the South China Sea, it was concluded that the coal forming activities in the South China Sea presented particularity and complexity. Furthermore, the coal forming mechanisms also presented distinctiveness. The marginal basins in the South China Sea consist of several large and complex rift or depression basins, which are distributed at different tectonic positions in the South China Sea. Therefore, the marginal basins in the South China Sea are not simple traditional units with onshore continental slopes extending toward the deep sea. The marginal basins are known to consist of multi-level structures and distinctive types of basins which differ from the continental regions to the sea. During the Oligocene, the existing luxuriant plants and beneficial conditions assisted in the development of peat. Therefore, the Oligocene was the significant period for the formation and aggregation of the peat. However, the peat did not form in unified sedimentary dynamic fields,but instead displayed multi-level geographical units, multiple provenance areas, instability, and nonevent characteristics. As a result, the marginal basins in the South China Sea are characterized by non-uniform peat aggregation stages. In another words, the majority of the peat had entered the marine system in a dispersive manner and acted as part of the marine deposits, rather than during one or several suitable coal-forming stages.These peat deposits then became the main material source for hydrocarbon generation in all of the marginal basins of the South China Sea. The study will be of much significance for the hydrocarbon exploration in the marginal basins of the South China Sea.  相似文献   
993.
青海省位于青藏高原的东北部,处于秦祁昆造山系和北羌塘—三江造山系两个一级构造单元的拼合部位,先后经历了基底形成、发展及原—古—新特提斯洋扩张消减、闭合碰撞的复合造山及高原隆升过程,并在长期的地质构造演化中,在特定的时空域相伴发生不同的成矿作用并形成与之相配套的矿床系列。本文根据青海省“358地质勘查工程”及找矿突破战略行动实施以来取得的最新矿产勘查成果,通过对已发现的137种矿产、895处矿床和4 597处矿(化)点的成矿地质构造环境、成矿地质条件、成矿特征、成矿作用、成因类型、成矿时代及成矿规律的系统总结研究,运用陈毓川等提出的成矿系列理论,按照5个成矿系列序次(层次),划分出青海省主要矿床成矿系列组14个、成矿系列46个,成矿亚系列76个和矿床式131个。最后提出了最具找矿前景的11个成矿系列组、25个成矿系列、44个成矿亚系列及其63个典型矿床式,并按成矿区带做了简要总结分析。  相似文献   
994.
朱羽佳  汪德根  曾鹏 《热带地理》2021,41(3):528-539
以长三角城市群为例,采用多层Logistic回归分析方法,分析城市流动人口长期居留意愿的空间格局及其影响因素.研究发现:1)长三角城市群流动人口长期居留意愿比例为38.09%,其中安徽的城市流动人口以省内流入为主,长期居留意愿比例普遍较高;而沪、苏、浙的城市大多以省际迁移人口为主,高和较高居留意愿城市主要为上海、南京、...  相似文献   
995.
The photodissociation regions located between ionized regions and molecular clouds are studied by using a one-dimensional model where molecular H2 are formed on the dust grains, and destructed by photodissociation. The escape probability method is used for the line transfer. The excitation of infrared emission lines of H2 by UV fluorescence in M17, by shock heating in Orion KL and mainly by UV fluorescence in NGC 2023 are discussed.  相似文献   
996.
根据古地磁、磁化率、粒度和重矿物分析及电镜扫描石英砂表面特征等测试手段的综合研究,西宁地区的黄土可分出从S_0至L_(17)的连续黄土——古土壤序列。它包括全新世黄土、马兰黄土、离石黄土和午城黄土,形成的时间为1.2MaB·P.。黄土粒度粗,且含有两个风成细砂分层。重矿物以不透明矿物、角闪石为主,次为绿泥石、锆石和金红石等。石英砂颗粒以次棱角状为主,其次为棱角状。石英砂表面机械结构中有众多的冰川作用痕迹和风力作用痕迹。本区黄土主要来源于青藏高原第四纪局部冰盖、冰川及其外围广大冰缘地区所产生的粉砂物质。西宁大墩岭黄土剖面详细地记录了1.2MaB·P.的环境变化信息。其中1.1MaB·P.形成的L_(15)顶部的细砂分层代表1.2Ma以来最为干冷的严酷时期。L_1和L_2是末次冰期和倒数第二次冰期的产物。倒数第二次冰期比末次冰期更为干冷,极盛时期为0.155MaB·P.。S_1S_3和S_4可能代表1.2Ma以来本区最为温暖湿润的时期。  相似文献   
997.
不同平面直角坐标系的转换包括平移、旋转和尺度因子4个参数,当转换系数矩阵严重病态时,参数解不可靠。考虑到自由网平差中的重心基准条件与转换模型的相关性,通过附加重心基准条件消去两个平移参数来解决转换矩阵严重病态的问题,从而求出正确的坐标转换参数。用实例对该方法进行了验证。  相似文献   
998.
We present a study of summer precipitation changes over the Yangtze River Valley (YRV) and North China (NC) simulated from 20 models of the CMIP3 (phase 3 of the Coupled Model Intercomparison Project). It is found that the LASG-FGOALS-g1.0 (fgoals) model has the highest ability in simulating both the interannual variability of individual regions and the seesaw pattern of the two regions observed during the past few decades. Analyses of atmospheric circulations indicate that the variability in precipitation is closely associated with the 850 hPa meridional winds over the two regions. Wetness in the YRV and dryness in NC are corresponding to strong meridional wind gradient and weak meridional wind over these two regions, respectively. The ability of a coupled general circulation model (CGCM) to simulate precipitation changes in the YRV and NC depends on how well the model reproduces both observed associations of precipitation with overlying meridional winds and observed meridional wind features in summer. Analysis of future precipitation changes over the two regions projected by the fgoals model under the IPCC scenarios B1 and A1B suggests a significant increase of 7–15% for NC after 2040s due to the strengthened meridional winds, and a slight increase over the YRV due to less significant intensification of the Mei-yu front.  相似文献   
999.
Summary ?This simulation study was applied by a regional climate model (RegCM2) and forced by reasonable soil temperature and humidity disturbances, in order to examine the disastrous weather and climate-produced such disturbances that were performed in a series of experiments of different climatic zones, seasons and space/time scales, to recognize the persistence and to understand the mechanisms of their respective climatic responses under the current climatic background of China. The simulation results showed that, in regions of East Asian monsoon climate, the soil humidity disturbance (SHD) has greater impact on posterior climate responses than the temperature disturbance has. The SHD forcing exerts noticeable influence on rainfall generally. Although the centers of changed precipitation generally do not coincide with those of the disturbances, the centers are located mostly in downwind areas of the SHD core and in areas of prevailing updraft, even some places far away; with neighboring dry/moist SHD zones, a bigger rainfall increase tends to show up in the dry region instead of in the wet one. The simulation suggested that the SHD lasts for a rather long time, whose length is controlled by the presence of a positive feedback between the precipitation, the synchronous circulation patterns, the latitude and season, and the intensity of the SHD forcing. This study has found that the humidity disturbance (especially from rainfall) is in good correspondence to posterior temperature that the previous SHD enhancement leads to the subsequent temperature drop in the surface and near-surface layer, while the centers of lowered temperature can remain more than three months. Received April 3, 2001; Revised December 19, 2001  相似文献   
1000.
水稻总叶龄模拟研究   总被引:1,自引:0,他引:1  
以水稻的生物学特性为依据,利用田间试验实测资料,经过统计分析,确立了水稻总叶龄与环境变量之间的相关关系,建立了不同品种种水稻的总叶龄模拟模式,发现日长是影响水稻总叶龄的主要因素,其次是温度。  相似文献   
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