震害现场紧急卫星通讯系统的研究和建设     

张建华  赖锡安  吴亚明  陈文明 《大地测量与地球动力学》1993,(4)

本文研究了应用VSAT技术建立大震现场紧急通讯系统的设计和实施方案,规定了该系统应实现的功能。在此基础上,提出了建立我国未来陆地地震救灾移动卫星通讯计划,并对一些关键技术和为移动用户可能提供的通讯业务进行了讨论。  相似文献   

印度河扇水道堤岸外侧更新世沉积物波发育特征与形成过程分析^*          下载免费PDF全文

浩克  纪友亮  张胜久  刘炎鑫  Khurram Shahzad  Saad Ahmed Mashwani  刘笑语  姜燕 《古地理学报》2022,24(2):389-404

印度河扇更新世发育的沉积物波结构复杂、形态多样,其形成过程的认识程度低。本次研究通过高分辨率地震数据和地震解释技术,研究了印度河扇沉积物波的波长、形态、波峰变化等形态特征;阐述了沉积物波与沉积物变形特征的差异、识别了两者的区分标志;总结了水道堤岸斜坡和区域斜坡上沉积物波的分布规律;在此基础上,讨论了沉积物波的形成机理和控制因素,分析了沉积物波的形成过程,并建立了印度河扇沉积物波的形成模式。研究表明: (1)研究区沉积物波波长平均为486.84 m,最大1473 m;波高在10~60 m之间,平均30 m。(2)沉积物波的形态有对称型和非对称型,其迁移方式有上坡迁移型、加积型和下坡迁移型;沉积物波主要发育在水道堤岸的斜坡上,在区域斜坡上也发育少量的沉积物波,这2种沉积物波波脊的走向差异很大,水道堤岸斜坡上的沉积物波主要分布于水道凹岸堤岸的外侧,距离水道越远其规模(波长、波高)越小,波脊走向近于NE-SW方向,与水道的走向平行或斜交;区域斜坡上的沉积物波波脊的走向多为NW-SE向,平行于区域斜坡的走向,离源区越远规模越大。(3)水道堤岸斜坡上的沉积物波是由水道型浊流在离心力的作用下,溢出水道的凹岸,在堤岸外侧的斜坡上沉积形成的,堤岸斜坡的角度对沉积物波的发育规模影响不大,浊流的强度和输沙量对其规模影响大;区域斜坡上发育的沉积物波是由顺坡而下的非水道化的浊流沉积形成;滑塌变形造成的起伏地貌以及早期沉积物波的存在,也都影响了后期沉积物波的发育。  相似文献   

Mapping soil liquefaction susceptibility across Europe using the analytic hierarchy process     

Meisina  C.  Bonì  R.  Bozzoni  F.  Conca  D.  Perotti  Cesare  Persichillo  Pina  Lai  C. G. 《Bulletin of Earthquake Engineering》2022,20(11):5601-5632

Bulletin of Earthquake Engineering - Mapping the susceptibility of earthquake-induced soil liquefaction at the continental scale is a challenge. Susceptibility of soils to liquefaction is the...  相似文献   

High effectiveness of GRACE data in daily-scale flood modeling: case study in the Xijiang River Basin,China     

Xiong  Jinghua  Wang  Zhaoli  Guo  Shenglian  Wu  Xushu  Yin  Jiabo  Wang  Jun  Lai  Chengguang  Gong  Qiangjun 《Natural Hazards》2022,111(1):507-522

Natural Hazards - The U.S. 2020 hurricane season was extraordinary because of a record number of named storms coinciding with the COVID-19 pandemic. This study draws lessons on how individual...  相似文献   

A fuzzy comprehensive evaluation model for flood risk based on the combination weight of game theory   总被引：3，自引：2，他引：1  

Chengguang Lai  Xiaohong Chen  Xiaoyu Chen  Zhaoli Wang  Xushu Wu  Shiwei Zhao 《Natural Hazards》2015,77(2):1243-1259

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Band selection using sparse nonnegative matrix factorization with the thresholded Earth’s mover distance for hyperspectral imagery classification     

Weiwei Sun  Weiyue Li  Jialin Li  Yenming Mark Lai 《Earth Science Informatics》2015,8(4):907-918

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Banking Across Boundaries: Placing Finance in Capitalism by Brett Christophers. Chichester,Wiley‐Blackwell, 2013, pp. xi + 290 (ISBN: 978‐1‐4443‐3828‐7).          下载免费PDF全文

Karen Lai 《Singapore journal of tropical geography》2015,36(1):127-128

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Simulation of summer precipitation diurnal cycles over the Tibetan Plateau at the gray-zone grid spacing for cumulus parameterization     

Ou  Tinghai  Chen  Deliang  Chen  Xingchao  Lin  Changgui  Yang  Kun  Lai  Hui-Wen  Zhang  Fuqing 《Climate Dynamics》2020,54(7):3525-3539

Climate Dynamics - The Tibetan Plateau (TP) is often referred to as the “water tower of Asia” or the “Third Pole”. It remains a challenge for most global and regional models...  相似文献   

樟树市气象干旱特征及重现期分析          下载免费PDF全文

刘喆玥  韩会明  赖亮  杨立苑  徐全倩 《气象与减灾研究》2020,43(2):117-122

利用樟树市1960—2018年逐月降水和气温资料,计算标准化降水蒸散指数（SPEI）,并结合游程理论和Copula函数分析了该地区干旱特征。结果表明：樟树市干旱形势总体上趋于缓和,干旱历时和干旱烈度均呈减弱趋势,且呈现出良好的相关性;Frank-Copula函数可作为描述该地区干旱历时和干旱烈度的二维联合分布最优函数;在相同干旱历时和烈度下,“且”的重现期大于“或”的重现期,樟树市历史干旱事件的干旱历时多小于5个月,“且”的重现期小于10 a。  相似文献   

Wave excitation in three-dimensional discs by external potential     

Hang Zhang  Dong Lai 《Monthly notices of the Royal Astronomical Society》2006,368(2):917-934

We study the excitation of density and bending waves and the associated angular momentum transfer in gaseous discs with finite thickness by a rotating external potential. The disc is assumed to be isothermal in the vertical direction and has no self-gravity. The disc perturbations are decomposed into different modes, each characterized by the azimuthal index m and the vertical index n , which specifies the nodal number of the density perturbation along the disc normal direction. The   n = 0  modes correspond to the two-dimensional density waves previously studied by Goldreich & Tremaine and others. In a three-dimensional disc, waves can be excited at both Lindblad resonances (LRs; for modes with   n = 0, 1, 2, …  ) and vertical resonances (VRs; for the   n ≥ 1  modes only). The torque on the disc is positive for waves excited at outer Lindblad/vertical resonances and negative at inner Lindblad/vertical resonances. While the   n = 0  modes are evanescent around corotation, the   n ≥ 1  modes can propagate into the corotation region where they are damped and deposit their angular momenta. We have derived analytical expressions for the amplitudes of different wave modes excited at LRs and/or VRs and the resulting torques on the disc. It is found that for   n ≥ 1  , angular momentum transfer through VRs is much more efficient than LRs. This implies that in some situations (e.g. a circumstellar disc perturbed by a planet in an inclined orbit), VRs may be an important channel of angular momentum transfer between the disc and the external potential. We have also derived new formulae for the angular momentum deposition at corotation and studied wave excitations at disc boundaries.  相似文献