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171.
Anqi Wang Debin Yang Haotian Yang Maosong Mu Yikang Quan Leran Hao Wenliang Xu 《地学前缘(英文版)》2021,12(3):343-357
Mesozoic sedimentary units within the Nanzhao and Mashiping basins record the paleogeographic and tectonic evolution of the Qinling Orogen (QO). This study uses... 相似文献
172.
Based on the latest oceanic surface drifter dataset from the global drifter program during 2000–2019, this study investigated the global variation of relative frequency shift(RFS), near-inertial energy(NIE) and inverse excess bandwidth(IEB) of near-inertial motions, and analyzed their relations with oceanic mesoscale dynamics, relative vorticity and strain. Compared with previous works, we have some new findings in this study:(1) the RFS was high with negative values in some regions in which we found a significant blue shift of the RFS in the equatorward of 30°N(S) and from 50°N to 60°N in the Pacific, and a red shift in the western boundary currents and their extension regions, the North Atlantic and the Antarctic Circumpolar Current regions;(2) more peak values of the NIE were found in global regions like the South Indian Ocean, the Luzon Strait and some areas of the South Ocean;(3) the global distribution of the IEB were characterized by clear zonal bands and affected by vorticity and wind field;(4)the RFS was elevated as the absolute value of the gradient of vorticity increased, the IEB did not depend on the gradient of vorticity, and the eddy kinetic energy(EKE) weakened with the decrease of the absolute value of RFS;(5) the NIE decreased with increasing absolute value of the relative vorticity and the gradient of vorticity, but it increased with increasing strain and EKE when EKE was larger than 0.003 2 m~2/s~2. 相似文献
173.
174.
改进的能量守恒方法及其在CHAMP重力场恢复中的应用 总被引:1,自引:0,他引:1
XU Tianhe HE Kaifei Xi’an Research Institute of Surveying Mapping Middle Yanta Road Xi’an China. 《地球空间信息科学学报》2008,11(3):168-173
An efficient method for gravity field determination from CHAMP orbits and accelerometer data is referred to as the energy balance approach. A new CHAMP gravity field recovery strategy based on the improved energy balance approach IS developed in this paper. The method simultaneously solves the spherical harmonic coefficients, daily Integration constant, scale and bias parameters. Two 60 degree and order gravitational potential models, XISM-CHAMPO1S from the classical energy balance approach, and XISM-CHAMPO2S from the improved energy balance, are determined using about one year's worth of CHAMP kinematic orbits from TUM and accelerometer data from GFZ. Comparisons among XISM-CHAMPO1S, XISM-CHAMPO2S, EIGEN-CGO3C, EIGEN-CHAMPO3S, EIGEN2, ENIGNIS and EGM96 are made. The results show that the XISM-CHAMPO2S model is more accurate than EGM96, EIGENIS, EIGEN2 and XISM-CHAMPO1S at the same degree and order, and has almost the same accuracy as EIGEN-CHAMPO3S. 相似文献
175.
基于交互多模型的水下目标跟踪方法 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
176.
地理信息数据质量的概念、评价和表述——地理信息数据质量控制国家标准核心内容浅析 总被引:2,自引:1,他引:1
介绍已经报批的国家标准<地理信息质量原则>和<地理信息质量评价过程>所确定的地理信息数据质量元素、子元素及其描述符,数据质量评价的方法、内容和要求,以及数据质量评价结果的表达方法,并就我国这一领域存在的问题和相关标准及今后的发展简单地进行了分析. 相似文献
177.
本文导得了1个研究内波分裂的射线型二维KdV方程。利用这一方程的一维退化方程进行了实验室尺度下孤立子型内波分裂的数值研究。数值结果表明,深水区的初始内孤立波和实测的内孤立波(内潮)在通过陆坡区时都会产生分裂,并在陆架上(浅水区)生成一内孤立子波列。这表明在实际海洋条件下,深海区内潮的分裂是陆架上海洋内孤立子波包(或波列)生成的主要机制之一。 相似文献
178.
179.
Guo-Wei Ren Hao-Jing Zhang Xiong Zhang Nan Ding Xing Yang Fu-Ting Li Pei-Lin Yan Xiao-Lin Xu 《天文和天体物理学研究(英文版)》2021,(3):243-250
In this work,we have searched for quasi-periodic oscillations(QPOs)in the 15 GHz light curve of the FSRQ PKS J0805-0111 monitored by the Owens Valley Radio Observatory(OVRO)40 m telescope during the period from 2008 January 9 to 2019 May 9,using the weighted wavelet Z-transform(WWZ)and the Lomb-Scargle Periodogram(LSP)techniques.This is the first time to search for a periodic radio signal in the FSRQ PKS J0805-0111 by these two methods.Both methods consistently reveal a repeating signal with a periodicity of 3.38±0.8 yr(>99.7%confidence level).In order to determine the significance of the periods,the false alarm probability method was applied,and a large number of Monte Carlo simulations were performed.As possible explanations,we discuss a number of scenarios including the thermal instability of thin disks scenario,the spiral jet scenario and the binary supermassive black hole scenario.We expect that the binary black hole scenario,where the QPO is caused by the precession of binary black holes,is the most likely explanation.FSRQ PKS J0805-0111 thus could be a good binary black hole candidate.In the binary black hole scenario,the distance between the primary black hole and the secondary black hole is about 1.71×1016 cm. 相似文献
180.
根据单次散射(Aki)模型,利用2003年至今山东台网记录的26次2.9级以上地震的数字化地震波,研究并探讨了胶东半岛及两侧海域平均尾波Q值,在1~18Hz的频率域范围内,Q值与频率的依赖关系为:胶东北部海域Qc=(313士42),f^(0.653±0.145),胶东内陆Qc=(319±88)f^(0.649±0.145),黄海海域Qc=(259±60)f^(0.757±0.277),与国内其他区域尾波Q值研究结果相比,本区域Qc为高值、对频率低依赖性区域。可能与本研究区内构造活动弱、地震活动水平低有关。 相似文献