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181.
t Gravity anomalies on a2.5 ×2.5 arc-minute grid in a non-tidal system were derived over the South China and Philippine Seas from multi-satellite altimetry data. North and east components of deflections of the vertical were computed from altimeter-derived sea surface heights at crossover locations, and gridded onto a 2.5 × 2.5 arc-minute resolution grid. EGM96-derived components of deflections of the vertical and gravity anomalies gridded into 2.5 × 2.5 arc-minute resolutions were then used as reference global geopotential model quantities in a remove-restore procedure to implement the Inverse Vening Meinesz formula via the 1D-FFT technique to predict the gravity anomalies over the South China and Philippine Seas from the gridded altimeter-derived components of deflections of the vertical. Statistical comparisons between the altimeter-derived and the shipboard gravity anomalies showed that there is a root-mean-square agreement of 5.7 mgals between them.  相似文献   
182.
基于交互多模型的水下目标跟踪方法(英文)   总被引:1,自引:0,他引:1  
According to the requirements of real-time performance and reliability in underwater maneuvering target tracking as well as clarifying motion features of the underwater target, an interacting multiple model algorithm based on fuzzy logic inference (FIMM) is proposed. Maneuvering patterns of the target are represented by model sets, including the constant velocity model (CA), the Singer mode~, and the nearly constant speed horizontal-turn model (HT) in FIMM technology. The simulation results show that compared to conventional IMM, the reliability and real-time performance of underwater target tracking can be improved by FIMM algorithm.  相似文献   
183.
A review was conducted on the environmental evolvement and environmental archaeological research since the 1980s in the Yangtze Delta. Former environmental evolvement and environmental archaeological research results can be summed up into 4 aspects: 1) Formation and evolution of the Taihu Lake; 2) Transgression and sea-level changes in the Holocene epoch; 3) Reconstruction of the pre-historical environment; and 4) Impacts of environmental variations on the rise and fall of human civilization (formation of the cultural interruptions). Based on this review, some limitations in the present research methods and possible outcomes are pointed out in this paper.  相似文献   
184.
SVLBI (space very long baseline interferometry) has some important potential applications in geodesy and geodynamics, for which one of the most difficult tasks is to precisely determine the orbit of an SVLBI satellite. This work studies several technologies that will possibly be able to determine the orbit of a space VLBI satellite. Then, according to the types and charac- teristics of the satellite and the requirements for geodetic study and the geometry of the GNSS (GPS, GALILEO) satellite to track the space VLBI satellite, the six Keplerian elements of the SVLBI satellite (TEST-SVLBI) are determined. A program is designed to analyze the coverage area of space of different altitudes by the stations of the network, with which the tracking network of TEST-SVLBI is designed. The efficiency of tracking TEST-SVLBI by the network is studied, and the results are presented.  相似文献   
185.
利用雷电定位系统进行电网雷击故障快速查询(英文)   总被引:1,自引:0,他引:1  
At present, lightning is one of the 10 natural disasters, and it is also the top environmental factor of power interruption. It often causes huge losses to the electric system. The Wuhan High Voltage Institute of the State Grid Corporation of China and Huazhong University of Science and Technology have been researching and developing lightning location systems (LLSs) since the late 1980s. In the mid-1990s, a lightning detection network was created in 29 provinces and cities in China. It is primarily applied to rapidly find lightning accidents, which greatly reduces power interruption. Also, it ensures high efficiency and safe operation of the electricity system. Remarkable benefit is achieved. China's LLS went through an "orientation positioning - time difference positioning - integrated positioning" development process. The positioning precision, detection efficiency, degree of automation, practicability and applied range are improved. Also, a lightning information system plan of the national network has been implemented, which services the whole society.  相似文献   
186.
为了减小我国北方隐盲型砂岩铀矿找矿中钻孔布设的盲目性,实现快速评价,在二连盆地SNT地区开展了土壤氡法寻找砂岩型铀矿工作。经测量数据的统计处理,在测区内固定了有一定规模的氡异常晕6个。通过氡异常评价并结合该区地质、地球物理和地球化学条件,预测了3个远景段,经钻探在其中的一个远景段中发现了砂岩型铀矿化,表明在我国北方中一新生代盆地中开展土壤氡法寻找隐盲型砂岩铀矿是有效且可行的。  相似文献   
187.
Geochronological studies on the crust-derived Tianmenshan pluton were undertaken by SHRIMP zircon U-Pb dating and Ar-Ar dating of biotite, muscovite and K-feldspar, giving a petrogenetic age of 167 Ma. Owing to the closure systems in different minerals, the cooling history of the pluton can be determined with an age-temperature diagram. The late hydrothermal event has been recognized, which is related probably with mineralization. In terms of the comparative geochronological and petrologic records, it is concluded that there are some constrains on tectonic evolution and that the formation of the Tianmenshan pluton proceeded in a transition period from Indosinian post-orogeny extension to strong compressive tectonics. And the timing of the hydrothermal event matches the compressive climax of the Yanshanian orogeny. The temporal gap between granite emplacement and wolframite mineralization could last 10-20 Ma owing to the low cooling rate of the pluton.  相似文献   
188.
Studies on rain-runoff process in the peripheral mountainous area of the Sichuan Basin, which is regarded as a key ecological shelter, will contribute to flood control and environmental protection for the Upper Yangtze River Basin. In two typical catchments--the Fujiang River Catchment and the Wujiang River Catchment, rainfall simulations have been conducted to study the rain-runoff processes of yellow soil and limestone soil in three types of land use--forestland, farmland and grassland. Results showed that (1) within the same rainfall process, overland flow occurs first on farmland, then on grassland, and finally on forestland; (2) soil surface coverage has a great impact on the occurrence and amount of overland flow. The runoff amount can increase 2-4 times after the coverage is removed; (3) the infiltration before the occurrence of overland flow will decrease because of higher gravel contents of soil, but it takes no effect on infiltration once overland flow becomes stable; (4) the runoff coefficient of the limestone soil forestland is greater than that of the yellow soil forest land, but less than that of the farmland; (5) three empirical infiltration models, including Horton' model, Kostiakov' model, and modified Kostiakov' model, were compared by using the observed results under rainfall simulation. The results showed that the Kostiakov' model performed better than both the Horton' model and modified Kostiakov model. According to the results of this research, the Kostiakov's model can be used to simulate rainfall infiltration when water erosion is modeled in the peripheral mountainous area of the Sichuan Basin.  相似文献   
189.
190.
Use of laser range and height texture cues for building identification   总被引:1,自引:0,他引:1  
Airborne LiDAR has found application in an increasing number of mapping and Geo-data acquisition tasks. Apart from terrain information generation, applications such as automatic detection and modeling of objects like buildings or vegetation for the generation of 3-D city models have been explored. Besides the height itself, height texture defined by local variations of the height is a significant parameter for object recognition. The paper explores the potential of the analysis of height texture as a cue for the automatic detection of objects in LiDAR datasets. A number of texture measures were computed. Based on their definition and computation these measures were used as bands in a classification algorithm, and objects like buildings, single trees, and roads could be recognized.  相似文献   
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