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1.
近年来, 信息技术的广泛应用正在对产业集群的形成和发展产生着深刻的影响。基于现 代信息技术所形成的网络联系逐渐成为产业集群关系网络的主要内容之一, 是深刻理解产业集 群演化和升级机制的重要方面。特别是, 信息技术可以使产业集群内中小企业空间联系的范围扩 大、时间成本下降, 为其走向全球市场提供便利的条件。本文首先回顾了我国企业信息技术应用 的发展过程与具体形式, 并在此基础上阐述了影响中小企业集群中信息技术应用的主要因素, 最 后以浙江省温岭市鞋业集群为案例分析了这些因素的具体作用。 相似文献
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The Ulleung Basin, East Sea/Japan Sea, is a Neogene back-arc basin and occupies a tectonically crucial zone under the influence of relative motions between Eurasian, Pacific and Philippine Sea plates. However, the link between tectonics and sedimentation remains poorly understood in the back-arc Ulleung Basin, as it does in many other back-arc basins as well, because of a paucity of seismic data and controversy over the tectonic history of the basin. This paper presents an integrated tectonostratigraphic and sedimentary evolution in the deepwater Ulleung Basin using 2D multichannel seismic reflection data. The sedimentary succession within the deepwater Ulleung Basin is divided into four second-order seismic megasequences (MS1 to MS4). Detailed seismic stratigraphy interpretation of the four megasequences suggests the depositional history of the deepwater Ulleung Basin occurred in four stages, controlled by tectonic movement, volcanism, and sea-level fluctuations. In Stage 1 (late Oligocene through early Miocene), syn-rift sediment supplied to the basin was restricted to the southern base-of-slope, whereas the northern distal part of the basin was dominated by volcanic sills and lava flows derived from initial rifting-related volcanism. In Stage 2 (late early Miocene through middle Miocene), volcanic extrusion occurred through post-rift, chain volcanism in the earliest time, followed by hemipelagic and turbidite sedimentation in a quiescent open marine setting. In Stage 3 (late middle Miocene through late Miocene), compressional activity was predominant throughout the Ulleung Basin, resulting in regional uplift and sub-aerial erosion/denudation of the southern shelf of the basin, which provided enormous volumes of sediment into the basin through mass transport processes. In Stage 4 (early Pliocene through present), although the degree of tectonic stress decreased significantly, mass movement was still generated by sea-level fluctuations as well as compressional tectonic movement, resulting in stacked mass transport deposits along the southern basin margin. We propose a new depositional history model for the deepwater Ulleung Basin and provide a window into understanding how tectonic, volcanic and eustatic interactions control sedimentation in back-arc basins. 相似文献
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利用加拿大大气环境局第二次冬季风暴观测(简称CASPⅡ)的部分资料,对加拿在东海岸冬季风暴的发生,发展情况进行了分析,结果表明,大多数风暴能达到爆发性发展程度,并对其中一个形成眼区的强风暴例子做了进一步讨论。 相似文献
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随着地质大调查的开展,豫西地区新的找矿进展和预测成果不断涌现,使之成为我国重点找矿地区之一,需要对其开展系统的成矿区划和部署研究工作。本文以新的研究成果和找矿突破为基础,通过综合分析,在该地区划分新的重要成矿部署区带,厘定边界并将其命名为\"豫西Au-Mo-W-Pb-Zn-Ag-Fe-铝土矿-石墨成矿带\"。结合区域成矿地质背景的综合研究,在区内划分了10个成矿亚带,初步建立了Au-Mo-W-Pb-Zn-Ag-Fe-铝土矿-石墨成矿带成矿谱系,其成矿作用具有多期次发育和多系统控制的特点,在时间演化上表现为多旋回性、继承性、新生性和叠加性特点,主要成矿期有前寒武纪、寒武纪-早石炭世、晚石炭世-中三叠世和晚三叠世-早白垩世,其中晚侏罗世-早白垩世是内生金属矿床成矿大爆发期。研究区主要成矿类型为岩浆热液型金银铅锌矿、斑岩型-矽卡岩型钼钨矿、层控热液型和海相火山岩型铅锌矿、古风化壳残积型铝土矿、沉积-变质型铁铜石墨矿和伟晶岩型稀有金属矿等。结合区域找矿进展和潜力评价最新成果,认为本区金、钼钨、铅锌银、铝土矿、铁、石墨、煤矿潜力巨大,为下一步勘查部署的主攻矿种,同时在本区划分了25个远景区,其中14个为重点远景区,11个为一般远景区,对研究区下一步矿产勘查部署工作有一定指导意义。 相似文献
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对晋西北地区表层土壤的物质组成进行研究,可以明确其物质来源、沉积环境及化学风化特征。选择区内表层土壤(深度0、10、20 cm)及其附近的河流沉积物,进行粒度和化学元素组成测试。结果表明:(1)晋西北地区表层土壤粒度组成以黏土和粉沙为主,且有自地表向下粗颗粒组分含量增加的趋势。(2)常量化学元素组成以SiO2、Al2O3、CaO、Fe2O3为主,其余元素含量均较低。化学元素组成模式表明研究区内表层土壤物质与黄土高原腹地黄土有相同的物质源区,黄河河流沉积物对其贡献不大。(3)晋西北表层土壤的CIA值为52.70~57.89,平均54.06,说明它们的化学风化程度较低,处于早期的脱Na、Ca阶段。这是由于研究区地理位置比洛川更靠北,气温和降水量均低于洛川,降水量与兰州相差不大,但是年平均气温和年温差比兰州低。该研究明确了晋西北地区表层土壤的物质组成特征,为区域潜在沙漠化危害防治提供了数据支撑。 相似文献
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Northwestern Anatolia contains three main tectonic units: (a) the Pontide Zone in the north which consists mainly of the Gstanbul-Zonguldak Unit in the west and the BallLda<-Küre Unit in the east; (b) the Sakarya Zone (or Continent) in the south, which is juxtaposed against the Pontide Zone due to the closure of Paleo-Tethys prior to Late Jurassic time; and (c) the Armutlu-OvacLk Zone which appears to represent a tectonic mixture of both zones. These three major tectonic zones are presently bounded by the two branches of the North Anatolian Transform Fault. The two tectonic contacts follow older tectonic lineaments (the Western Pontide Fault) which formed during the development of the Armutlu-OvacLk Zone. Since the earliest Cretaceous, an overall extensional regime dominated the region. A transpressional tectonic regime of Coniacian/Santonian to Campanian age caused the welding of the Gstanbul-Zonguldak Unit to the Sakarya Zone by an oblique collision. In the Late Campanian, a transtensional tectonic regime developed, forming a new basin within the amalgamated tectonic mosaic. The different tectonic regimes in the region were caused by activity of the Western Pontide Fault. Most of the ophiolites within the Armutlu-OvacLk Zone belong to the Paleo-Tethyan and/or pre-Ordovician ophiolitic core of the Gstanbul-Zonguldak Unit. The Late Cretaceous ophiolites in the eastern parts of the Armutlu-OvacLk Zone were transported from Neo-Tethyan ophiolites farther east by left-lateral strike-slip faults along the Western Pontide Fault. There is insufficient evidence to indicate the presence of an ocean (Intra-Pontide Ocean) between the Gstanbul-Zonguldak Unit and the Sakarya Zone during Late Cretaceous time. 相似文献
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矢量地理数据具有位置精度高、语义丰富、空间关系明确等特点,易于同各类专题信息集成、融合使用,是地理信息系统的一类重要数据源.互联网和大数据背景下,矢量地理数据面临泄密、侵权、窃取等安全隐患日益凸显.为此,本文分析比较了几类主要的矢量空间数据安全技术,认为数据置乱技术具有较为均衡的安全防护性能,实际应用潜力大,将经典的图像数据置乱思路引入矢量地理数据,提出了一种基于三维Arnold变换的矢量地理数据置乱加密方法.实验表明,该方法简洁高效,具有置乱度高、保持原有数据结构、完全可逆和抗暴力攻击等特点. 相似文献
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NIU Dongfeng LI Baosheng DU Shuhuan WEN Xiaohao QIU Shifan OU Xianjiao YANG Yi 《地理学报》2008,18(1):26-36
The components of the primary elements in the dune sands for the MGS1 subsec-tion of the Milanggouwan section in the Salawusu River valley, compared with those of mod-ern dune sands, show that they were caused by East Asian winter monsoon in the Mu Us desert during Holocene. The examined ages for the 11 layers of dune sands, based on the average sedimentary rate, are: 0 to 960, 1350–2240, 2470 to 3530, 4000 to 4180, 4290 to 4350, 4380 to 4760, 5040 to 5920, 6570 to 8270, 9020 to 9700, 9880 to 10160 and 10580 to 11080 a BP, respectively. The climatic events indicated by these dune sands are consistent with those records in the Huguangyan volcanic lake, Zoige peat bog, Hulu cave and Dunde ice core, particularly with the climatic fluctuations of the North Atlantic since 11 000 a BP. Among them, patterns from B0 to B8 correspond to the peak values of 0MD, 2D, 4D, 6D+8D+10D, 12D, 14D, 16D, 18D and 20D respectively. It might be caused by the North Atlantic ice age induced by the heat circulation, which strengthened the polar high pressure and Siberian-Mongolian high pressure and further led to the dominance of the winter mon-soon over China’s desert area. 相似文献