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41.
中国中部地区TID激发源的统计分布   总被引:3,自引:1,他引:3       下载免费PDF全文
利用武汉电离层观象台1985-1990年间的高频多普勒台阵观测资料,采用射线追踪方法,对观测到的电离层重力波扰动(TID)进行了定源研究,从统计上分析了扰动源的地理分布、季节变化以及与地磁活动的关系.结果表明,中国中部上空TID的激发源主要出现在春夏季的四川盆地和冬半年的山口地区.扰动的激发可能与青藏高原地形隆起对这两个地区的气象活动的影响有关.此外,有少部分尺度较大的扰动出现在冬半年,它们可能来自极区.  相似文献   
42.
运用主成分分离及线性区段等方法 ,使早白垩世样品明显分离出二组磁组分 .叠加剩磁为喜山期重磁化 ,特征剩磁明显偏离现代地磁场方向 ,经倾斜校正后 ,有很好的一致性并通过了倒转检验 ,给出塔里木地块库车坳陷早白垩世巴西盖组古地磁新数据 .综合已有的古地磁结果 ,获得了塔里木地块早白垩世平均剩磁方向及平均古地磁极 ,阐明了塔里木地块早白垩世磁倾角明显偏低这一现象 .分析导致磁倾角偏低的诸多因素 ,认为压实作用可能是导致磁倾角偏低的重要因素之一 .  相似文献   
43.
三门峡盆地晚新生代沉积物磁性载体类型   总被引:3,自引:2,他引:3       下载免费PDF全文
对三门峡盆地晚新生代沉积岩样品进行岩石磁学研究,通过三轴饱和等温剩磁和剩磁矫顽力实验、交变退磁和热退磁实验及磁化率测定,发现黄土-古土壤、河湖相灰绿层和冲洪积层3种不同岩性的磁载体存在显著差异.即黄土-古土壤以磁铁矿为主,赤铁矿和磁赤铁矿很少;河湖相灰绿色沉积磁性矿物含量较低,主要为赤铁矿和磁铁矿,但磁铁矿较多,此外还有一些不稳定磁性矿物(如针铁矿、菱铁矿等);冲洪积物以磁铁矿和赤铁矿为主,磁铁矿相对较多.  相似文献   
44.
塔里木盆地热演化分析中热史波动模型的初探   总被引:14,自引:2,他引:14       下载免费PDF全文
用沉积盆地波动分析的观点,结合塔里木盆地的实际资料,初步建立一种新的热历史恢复模型--热史波动模型.利用该模型并结合镜质体反射率古温标模拟计算了塔中10井的热历史,同时用磷灰石裂变径迹数据对模拟结果进行了检验.此结果可以较客观地描述盆地热历史的复杂变化,特别为无古温标区或未钻达层位热演化研究提供了可能.  相似文献   
45.
三维井间电磁场的正反演计算   总被引:21,自引:7,他引:21       下载免费PDF全文
提出了一种计算体积分方程的方法-改进型局域非线性迭代(MLNI),并用其对三维井间电磁场进行反演计算,该方法将井间大尺度散射体分为近场和远场区域两部分,它们的位置和尺寸均随场点位置的变化而改变,采用局域非线性近似计算近场区域的影响,将远场区域的影响作为外部激励源,采用迭代方法计算,该方法具有计算速度快,所需内存量少,收敛性好的优点,在反演中采用基于MLNI的非线性反演方法,利用这种方法可以将成像区域集中于一定范围内而不是整个三维空间,该反演方法由于考虑到了雅可比矩阵元素的非线性项,因而与传统的Born迭代反演方法相比更为精确和稳定,考虑到信息量和计算机内存的限制,第1次成像采用双重体元分割法进行较粗略的成像,然后缩小成像范围进行第2次较精确的成像,数值计算结果表明,MLNI是一种有效的计算井间大尺度异常体散射场的方法,将该方法用于反演过程能够得到较高分辨率的三维井间电导率图像。  相似文献   
46.
The study provides a baseline for the assessment of the organic and inorganic pollution specially, heavy metal contamination in the surface sediments of Pyeongchang River,South Korea.The assessment of the study areas was done with respect to metal pollution load,ecological risk and geoaccumulated risk.Based upon the used indices,a priority index(Pindex) was used to rank the utmost contaminated sites.Though the concentrations of mercury in all sediments were below the guideline, the significant enriched contamination was observed by all applied indices.As expected,the values of pollution load index(PLI),ecological risk index(RI) and geoaccumulation risk index(Igeo) demonstrated lower heavy metal contamination in upstream areas compared to the downstream. Admittedly,sediments were unpolluted to slightly-polluted according to PLI while high to extremely high ecological risks were observed in several sediment samples.Furthermore,all the samples were uncontaminated as per Igeo.After simplification of Igeo,the Pindex,showed the utmost contaminated sediments with a value of 2.537.Notably,protective measures should be taken to the highly contaminated areas which are prioritized by Pindex Admittedly,the maximum concentrations of total organic carbon,total nitrogen,inorganic nitrogen,total phosphorous,inorganic phosphorous,calcium, magnesium,sodium and potassium were significantly observed as 7.8×104,3,185,36,1,032,3.7, 1,5163,2,881,669 and 4,076mg/kg accordingly.  相似文献   
47.
Mapping shoreline changes along coastal regions is critically important in monitoring continuously rising sea surface heights due to climate change and frequent severe storms. Thus, it is especially important if the region has very high tidal ranges over very gentle tidal flats, which is a very vulnerable region. Although the various remote sensing platforms can be used to map shoreline changes, the spatial and temporal resolutions are not enough to obtain it for a short time. Accordingly, in this study we introduce the newly developed low altitude Helikite remote sensing platform to achieve much better resolutions of shorelines and a bathymetry. The Helikite stands for Helium balloon and Kite, which is a kind of aerial platform that uses the advantages of both a Helium balloon and a kite. Field experiments were conducted in the Jaebu Island, off the coast of the west Korean Peninsula in January 29, 2011. In order to extract shorelines from the consecutive images taken by the low altitude Helikite remote sensing platform, active contours without edges (ACWE) is used. Edges or boundaries exist primarily on places between one type of objective and the other. Since the hydrodynamic pressure has an effect everywhere, the locations of the waterlines can be the isobath lines. We could map several waterlines, which would enable us to complete a local bathymetry map ranges from 35 to 60 cm depth. The error resulting from applying ACWE algorithm to the imagery to determine the waterline is approximately less than 1 m. Therefore, it is very unique way to obtain such high resolutions of bathymetry with high accuracy for the regions of extremely high tidal ranges for a short time.  相似文献   
48.
Park  Kwang-Soon  Heo  Ki-Young  Jun  Kicheon  Kwon  Jae-Il  Kim  Jinah  Choi  Jin-Yong  Cho  Kyoung-Ho  Choi  Byoung-Ju  Seo  Seung-Nam  Kim  Young Ho  Kim  Sung-Dae  Yang  Chan-Su  Lee  Jong-Chan  Kim  Sang-Ik  Kim  Seonjeong  Choi  Jung-Woon  Jeong  Sang-Hun 《Ocean Science Journal》2015,50(2):353-369
Ocean Science Journal - The Korea Operational Oceanographic System (KOOS) was developed at the Korea Institute of Ocean Science and Technology (KIOST) to produce real-time forecasting and...  相似文献   
49.
应用CT扫描技术对两种稳定非饱和状态的砂土试样分层进行扫描,得到不同深度CT扫描层图像,采用Image J图像处理软件将CT图像转化为CT数均值,然后在稳定非饱和试样中分别间断性连续注入污染物KI溶液,测定不同时间间隔CT扫描图像,计算注入污染物先后扫描图像结果的差值,建立CT数均值和污染物迁移之间的关系,研究污染物在非饱和砂土中的运移特征,得出非饱和砂土中污染物浓度随时间和深度的变化规律,对研究其他介质中污染物的迁移具有重要的指导作用。  相似文献   
50.
Haeundae Beach represents Korean pocket beaches that are currently erosional and dominated by summertime typhoons. The decadal wave characteristics 9 km offshore of Haeundae Beach were analyzed using the WAM model that was validated through the 2007 wave observations. The wave statistics modelled for 1979–2007 indicates that the seasonal mean significant wave height (H s ) is highest (0.6–0.7 m) in summer due to typhoons, in contrast to the lowest (around 0.5 m) autumn analog. The wave direction is also pronouncedly seasonal with the principal bearings of SSW and NE in the summer and winter seasons, respectively. The WAM results additionally show that the H s has gradually increased over the region of Haeundae Beach since 1993. Beach profiling during June–November 2014 shows the opposite processes of the typhoon and fair-weather on beach sands. During a typhoon, foreshore sands were eroded and then accumulated as sand bars on the surf zone. In the subsequent fair-weather, the sand bars moved back to the beach resulting in the surf-zone erosion and foreshore accretion. A total of 5 cycles of these beach-wide sand movements yielded a net retreat (up to 20 m) of the shoreline associated with large foreshore erosion. However, the surf zone only slightly accumulated as a result of the sand cycles. This was attributed to the sand escape offshore from the westernmost tip of the beach. The present study may provide an important clue to understanding the erosional processes in Haeundae Beach.  相似文献   
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