InSAR同震形变场及其在震源参数确定中的应用研究进展

合成孔径雷达干涉测量(InSAR)技术是20世纪70年代发展起来的一种空间大地测量技术,具有全天时、全天候、高精度、广域覆盖的优势,自20世纪90年代以来在地震地壳形变监测研究领域得到了广泛应用,对地震发生机理研究具有重要意义.尤其是InSAR技术观测的同震地壳变形结果可以为分析发震断层几何学特征和动力学机制提供重要约...     

Long-term ecological interactions between nutrient and phytoplankton community in the Changjiang estuary

Both nitrate (NO₃⁻) and soluble reactive phosphate (PO₄³⁻) concentration in the freshwater end-member at the mouth of the Changjiang River have increased dramatically since the 1960s. Within the same period in the sea area, with surface salinity>30, NO₃⁻ concentration has shown an obvious increase, PO₄³⁻ has not changed greatly and dissolved reactive silica (SiO₃²⁻) has deceased dramatically. An examination of the elemental ratio of NO₃⁻ to PO₄³⁻ at the mouth of the Changjiang River did not show a systematic trend from the 1960s to 2000s largely because both nutrients increased simultaneously. In comparison, the elemental ratio of dissolved inorganic nitrogen (DIN) to PO₄³⁻ in surface seawater, with salinity>22, has shown a clearly increasing trend. Furthermore, an overall historical change of the SiO₃²⁻:PO₄³⁻ ratio has undergone a reverse trend in this area. Based on the changes of SiO₃²⁻:PO₄³⁻ and DIN:PO₄³⁻ ratios, we can conclude that an overall historical change of SiO₃²⁻:DIN ratio has decreased in this area from the 1950–1960s to 2000s. The argument that phytoplankton productivity in the Changjiang estuary has been enhanced by increasing nutrient input from the riverine transport was supported by these results. A comparative study analyzing the shift of phytoplankton composition from the mid-1980s to 2000s was also made. The results indicated that the average yearly percentage of diatom species in the Changjiang estuary has decreased from 84.6% during 1985–1986 to 69.8% during 2004–2005. Furthermore, the average yearly percentage of diatom abundance in the Changjiang estuary decreased from 99.5% during to 75.5% over the same time period, while the abundance of dinoflagellates has increased dramatically, from 0.7% to 25.4%.     

雪卡毒素产毒藻(岗比亚藻)研究进展

雪卡毒素是一类富集于海洋珊瑚礁鱼体内的聚醚类化合物,由底栖小型甲藻岗比亚藻产生,经海洋食物链传递代谢为雪卡毒素并使鱼类染毒。雪卡毒素毒性强,是已知的危害性较严重的海洋生物毒素之一。然而,长期以来该毒素产毒藻(岗比亚藻)在分类学领域存在诸多争议。本文由此对国际上现有研究结果进行系统整理与归纳,内容包括岗比亚藻的分类与分布、生理生态学、毒理学,并提出研究展望。本文重点阐述了岗比亚藻的地理区域扩张事实、与大型附着基质藻的关系、环境因子对其生长和产毒的影响、种内和种间的产毒特征差异等。在此基础上,结合我国在该领域的研究现状,提出建议和展望。     

基于深度卷积神经网络的遥感图像船只识别

根据遥感图像的特点,针对海面目标难以准确识别的问题,提出了一种基于深度卷积神经网络的船只识别方法.首先利用分类网络进行图像的预分类,然后在分类结果的基础上,构成双通道的识别体制,识别网络采用Faster R-CNN.针对受云雾遮挡的船只识别问题,利用改进的深度卷积神经网络结构开展网络训练与调优,处理结果的F1-Scor...     

湖南罗桥锡多金属矿区土壤地球化学特征研究

文章通过对罗桥锡多金属矿区土壤地球化学元素分析表明,区内成矿元素地球化学背景值高,其中强富集元素Bi、Sn、As的丰度系数大于10,Pb、W、Be的平均含量高于地壳丰度4倍以上。元素空间分带性较明显,由大义山岩体向西到泥盆系分布区,出现从高温元素W、Sn、Bi、Be(Mo)—高中温元素Bi、Pb、Zn、As—中温元素Cu的变化,反映有岩浆热液活动特点。主成矿元素Sn与W、Be显著正相关,W、Be、Mo、Bi有很好的相关性,说明它们来自同一成矿阶段。当距离系数为15时,分别聚为W-Sn-Bi-Be-Mo-Cu-As和Pb-Zn两组。因子分析可将土壤元素分为高温与中温两个成矿元素组合,且高温元素与中温元素出现叠加,说明成矿的多期性;W、Sn、Bi、Be、Mo等高温成矿元素异常强度高、规模大,不同元素的异常套合好,尤其是W、Sn元素,具有很好的找矿潜力。提出了5处成矿地球化学异常找矿远景区。     

Automatic detection and correction algorithms for magnetic saturation in the SMFT/HSOS longitudinal magnetograms

A longitudinal magnetic field often suffers the saturation effect in a strong magnetic field region when the measurement is performed at a single-wavelength point and linear calibration is adopted.In this study,we develop a method that can judge the threshold of saturation in Stokes V/I observed by the Solar Magnetic Field Telescope(SMFT)and correct it automatically.The procedure is to first perform the second-order polynomial fit to the Stokes V/I vs.I/I_m(I_m is the maximum value of Stokes I)curve to estimate the threshold of saturation,then reconstruct Stokes V/I in a strong field region to correct for saturation.The algorithm is demonstrated to be effective by comparing with the magnetograms obtained by the Helioseismic and Magnetic Imager(HMI).The accuracy rate of detection and correction for saturation is~99.4%and~88%respectively among 175 active regions.The advantages and disadvantages of the algorithm are discussed.     

GIS路径寻优的方向优先搜索法

针对地理信息系统中特定的两点路径寻优问题，提出一种方向优先的快速搜索算法。该算法在路径搜索过程中，首先搜索与前进方向更加接近的方向，可以在搜索的早期找到最短路径，从而在以后的搜索中剪去更多的节点和分支，提高最优路径的搜索速度。     

一个含煤沉积模式

在从事鄂西宜昌地区下二迭统马鞍煤系找煤工作中,对于这一地区的含煤沉积的认识,逐渐形成了一个模式,即泥炭的堆积是在古地形影响下,由沉积物的自重和同沉积构造因素相迭加的结果。     

我国煤层气产业突破发展的建议与措施

煤层气的开发利用对保障煤矿安全生产、增加天然气供应具有重要意义。通过分析煤层气产业发展现状和当前制约产业发展的主要问题,从产业运行机制、技术发展方向、资金投入三个方面提出煤层气产业突破发展的建议与措施。产业体制与机制方面,应大力推进煤系资源的协同开发,完善产业相关配套政策措施,加大产业"放管服"改革力度。技术发展方面,将低煤阶煤层气、深部煤层气、关闭(产能退出)矿井作为煤层气产业突破发展的新方向,建议实施典型区"9+2"煤层气勘探开发模式,加强煤与煤系气科技攻关力度。资金投入方面,推广"矿业权公开竞争出让"机制,制定矿权作为股权的投资政策,加大矿权勘探开发投入考核力度,为我国煤层气产业的突破提供保障。     

相山铀矿田基底变质岩原岩恢复及构造环境判别

文章通过对相山铀矿田深部变质岩开展岩石学、矿物学及地球化学等方面的研究,以探讨相山基底变质岩原岩的属性和形成环境等特征。根据铀矿科学钻孔岩心样品地球化学分析显示,基底变质岩成熟度较高,显示高镁铁、富硅、富铝,低钠钾的特征,原岩总体呈中酸性。变质岩整体表现出相对富集Ba、U、Rb、K、Th等元素,亏损Nb、Sr、P、Ti等元素;轻、重稀土元素分馏较为明显,且轻稀土相对富集、重稀土相对亏损;δEu为0.6～1.1,平均为0.7,小于1,表现为负异常;δCe为2.9～3.9,平均为3.4,表现为正异常。根据变质岩稀土元素北美页岩标准化(NASC)蛛网图显示,样品稀土元素含量与北美页岩(NASC)含量相近,推测原岩具有沉积岩的特征。主量元素分布特征表明相山铀矿田基底变质岩原岩成分复杂,推测其原岩主要为一套陆源海相沉积泥质岩、砂岩及粉砂岩系列的浅变质作用类型的陆源碎屑岩,主要有岩屑砂岩、富镁沉积岩、泥质碳质硅质岩,可能有部分火山凝灰岩。根据主微量构造判别图,推测相山基底变质岩其原岩为大陆岛弧构造环境下形成的沉积碎屑岩。