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41.
This paper examines spatio-temporal characteristics of an oasis economy and its relationship with water and mineral resources in the Turim River Basin from 1965 to 2005. A spatial autocorrelation model, the center of gravity model, and index system of the regional central city are used to probe the evolution laws of spatial structure of oasis economy. The study finds that: 1) The economic centre of gravity, whose variation track during this period follows linear rote law, was moving from headstream to middle reaches of the Tarim River. 2) Positive spatial autocorrelation which showed a waving and ascending trend of regional economy was significant and the neighbor effect of regional economic growth was strengthened continuously. 3) The regional economic centre was located in Hotan City before 1980, moved to Aksu City during the 1980s and to Korla City after 1990. We conclude that above all, during the recent four decades the evolution of the oasis economy in this region has gone through three stages: a traditional agriculture stage (before 1980), oasis agriculture and agricultural product processing stage (1980-1990) and oasis energy industry stage (after 1990). Furthermore, the dependence degree of the oasis economy on natural resources in different stages are studied by using dominance index, regression model, and grey relation method, which shows that an oasis economy highly depends on water resources in the oasis agriculture and agricultural product processing stage while it depends more on mineral resources such as oil and natural gas during the oasis energy industry stage. 相似文献
42.
通过样方法和样线法对大兔屿进行植物资源调查,其主要的植被类型是亚热带常绿阔叶林、灌草丛。有维管植物69科,139属,152种。蕨类3科,3属,3种;裸子植物3科,3属,3种;被子植物63科,133属,146种。乔木20科,27属,30种;灌木31科,44属,46种,草本和藤本30科,68属,74种。其中,原生植物125种,外来植物27种,入侵植物10种,无珍稀濒危植物。植被群落的植物区系组成中,属的分析表明,大兔屿植物以热带、亚热带成分为主。种子植物属划分为12个分布区类型及其变型,其中成分最多的是泛热带分布及其变型,为区系总数的35.29%。群落以高位芽植物占主要优势,为46.71%。人工栽培的台湾相思林、马尾松林及木麻黄林总的覆盖率却高达80%。最后针对海岛特色景观的营造,对大兔屿植物资源的保护和利用提出相关的建议。 相似文献
43.
随着城市建设的迅速发展,打桩过程中对毗邻建筑物的振动影响程度的测定工作日趋显得重要。为了满足建设工程的需要,我们应用动测方法,测定打桩过程中的振动所激发的地动速率,进而通过数字处理,转换成加速度量,并根据地震烈度来确定打桩过程对周围建筑物的振动影响程度。从而对打桩过程的振动影响做出定量的估计。 相似文献
44.
相向而行的重力波与暴雨 总被引：5，自引：1，他引：5
本文对１９８８年７月２１日天津地区大暴雨的天气过程进行了详细分析，发现这次暴雨是两个中尺度系统引起的两片雨区相向移动、合并而后加强形成的。研究表明这是两个相向而行的大气重力内波叠加的结果。 相似文献
45.
Guo Xiaofeng Yang Wei Gao Zhiqiu Wang Linlin Hong Jinkyu Ding Baohong Zhao Long Zhou Degang Yang Kun 《Boundary-Layer Meteorology》2022,182(3):379-415
Boundary-Layer Meteorology - Based on observations over an alpine glacier, we investigate the turbulent flux dissimilarity between momentum and sensible heat transfer in a stably stratified... 相似文献
46.
关于用台站资料估算西北干旱区夏季感热通量的热力参数化比较 总被引：2，自引：0，他引：2
气象台站观测的气象要素可能受城市化等因子的影响而与野外试验站的观测存在一定的差异,这影响野外试验获取的热力参数直接应用于西北干旱区台站感热通量的估算。本文选取了一些常用的热力参数化方案(包括Z10、B82、Z98、Y08和Z12等方案),通过敦煌站夏季估算的感热通量与野外观测的比较以及对整个西北干旱区夏季感热通量的估算,评价了这些热力参数化对动量粗糙度的敏感性和在西北干旱区的适用性。结果显示,热力输送系数取定值的方案计算西北干旱区的感热通量可能存在较大不确定;台站的动量粗糙度可能受城市化等因子的影响,但在感热通量计算时建议取台站下垫面的动量粗糙度;Y08方案估算的感热通量相对比较合理,可以用来研究西北干旱区的夏季地表感热输送特征。 相似文献
47.
Quantitative analyses have been carried out on radiolarians from 65 samples of Core 255 in the southern Okinawa Trough. The
distribution of taxa and the results of Q-mode factor analysis show that during the last 20 000 years three radiolarian assemblages
could be distinguished which can be correlated to high and low productivity levels indicated by the organic carbon content,
radiolarian abundance and ratio of Nassellaria/Spumellaria in the sediment. TheTetrapyle quadriloba assemblage of thr last glaciation and deglaciation is associated with high productivity whereas the early HolocenePolysolenia spinosa and the middle and late HoloceneCarposhaera globosa assemblages correspond to low surface productivity. Meanwhile, the variations in the ratio of radiolarian fragments indicate
higher SiO2 dissolution during the Holocene than during the last glacial stage. 相似文献
48.
Zhuang Hanping Lu Jialan Fu Jiamo Liu Jinzhong Ren Chigang Zou Degang 《中国科学:地球科学(英文版)》1998,41(1):21-27
A heavy-media separation has brcu carried out to study the partition of germanium in various macetals ol mineralized lignites in Lincang superlarge gerrtlilnium deposit in Yunniln, China. The result shows that Ge stays predominantly in huminites, especially in corpohuminitrs (86.04–89.16%), next in light macerals and minerals (3.20%–8.33% and 1.71%–10.27%, respectively). In addition, the EPMA and PIXE analyses suggest that no germanium minerals have been detected and Ge is well distributed in the whole mineralized lignite, bonding to O, C and H of coaly organic matter of mineralized lignites.
相似文献49.
当前资源环境承载能力的研究多针对区域尺度,县域尺度地质资源环境承载能力评价较少。以江苏宜兴市为例,基于承载本底和承载状态建立了评价指标体系,并从地质资源、水土环境和地质安全3个方面,开展了地质资源环境承载能力评价,为县市地质资源环境承载能力评价技术要求制定提供了支撑和参考。评价结果显示,宜兴南部丘陵山区地质资源承载能力大于北部平原区,地质安全承载能力则小于北部平原区,水土地质环境承载能力总体为中等水平,提出宜兴市应加强南部山区资源环境保护与地质灾害防范,中部地区水土污染重点防控,为宜兴市地质资源合理利用与地质环境安全保障提供科学依据。 相似文献
50.
Crude oil as carrier of gold: petrological and geochemical evidence from Lannigou gold deposit in southwestern Guizhou, China 总被引：1，自引：0，他引：1
Organic matter is related closely to mineralization of Lannigou gold deposit in southwestern Guizhou, China. Regionally, the
distribution of organic carbon agrees well with that of faults within which gold deposits are hosted. Studies on organic petrology
show that pyrobitumen, which is related most closely to mineralization, adheres to quartz vein or fills quartz veinlet. Proton-induced
X-ray emission (PIXE) analysis shows an evident abundance of Au in pyrobitumen. Pyrobitumen paragenetically associates with
pyrite and arsenopyrite which are the main carrier minerals of Au. The thermal simulation experiment indicates that about
99% of Au will be concentrated in oil phase in the coexisting system of oil and brine and rock. The role of crude oil in ore-forming
process is: as carrier of Au, crude oil moves upwards, and undergoes thermal decomposition and thermochemical reduction when
it encounters the oxidizing fluid within the Trassic turbidity; Au is thus released from crude oil, reduced and precipitated.
Project supported by the Climbing Project (No. PA30) and the National Natural Science Foundation of China (Grant No. 49673190). 相似文献