江苏吕四小庙洪淹没性潮汐汊道的稳定性   总被引：9，自引：0，他引：9  

喻国华  陆培东 《地理学报》1996,51(2):127-134

运用沉积学、地貌学和海洋动力学方法，对小庙洪水道进行了历史演变、现代动态及稳定性分析，提出淹没性潮汐道的稳定性。淹没性潮汐道的开发利用必须顺应汊道自然演变规律，并考虑其内部稳定性差异。  相似文献   

微细浸染型金矿中原生矿石向氧化矿石转化机理探讨   总被引：5，自引：2，他引：5  

刘显凡  张兴春 《矿物学报》1997,17(4):501-506

本文以黔西南和桂西北微细浸染型金矿为例，讨论了该类型金矿原生矿石和氧化矿石中金的赋存状态差异，并从晶体化学和地球化学角度作了赋存原理分析，进而重点探讨了两类矿石中粘土矿物的表生淋滤转化的化学模式，为开展原生矿石的选冶工艺研究提供了新的思路。  相似文献   

湘南─粤北铁锰多金属矿床的表生风化作用          下载免费PDF全文

朱恺军  黄金水  姚国龙 《地质找矿论丛》1997,12(3):68-75

湘南－粤北是我国一个重要的铁锰多金属矿化带，该矿化带中重要的铁锰多金属矿 经历了海相沉积，热液改造和表生风化等多种地质作用。由沉积作用和热液改造作用形成的原生铁锰多金属矿化岩石，由于其中的成矿元素Ｆｅ，Ｍｎ，Ｐｂ，Ｚｎ和Ａｇ的含量低，有害元素Ｓ的含量高，工业价值不大。  相似文献   

360阶地球重力场模型DQM94A及其精度分析   总被引：4，自引：2，他引：4       下载免费PDF全文

夏哲仁  林丽  石磐 《地球物理学报》1995,38(6):788-795

介绍了适用于中国地区的３６０阶地球重力场模型ＤＱＭ９４Ａ．精度分析结果表明，应用局部积分改进的谱权综合法计算的３６０阶地球重力场模型ＤＱＭ９４Ａ，在表示中国境外地球重力场时，与用改进的基本模型ＯＳＵ９１Ａ精度相当；表示中国及其周边地区地球重力场的精度如下，用模型计算的３０＇×３０＇和１°×１°平均重力异常与相应实测结果较差的均方根基分别为±９．３０×１０^－５ｍ／ｓ２和±７．６５×１０^－５ｍ／ｓ２，在中国３７个ＧＰＳ点上，由ＤＱＭ９４Ａ计算的大地水准面高的精度为±０．８８ｍ．  相似文献   

Multiscale Combined Action and Disturbance Characteristics of Pre-summer Extreme Precipitation Events over South China     

Hongbo LIU  Ruojing YAN  Bin WANG  Guanghua CHEN  Jian LING  Shenming FU 《大气科学进展》2023,40(5):824-842

The dominant frequency modes of pre-summer extreme precipitation events(EPEs) over South China(SC) between1998 and 2018 were investigated. The 67 identified EPEs were all characterized by the 3–8-d(synoptic) frequency band.However, multiscale combined modes of the synoptic and three low-frequency bands [10–20-d(quasi-biweekly, QBW);15–40-d(quasi-monthly, QM); and 20–60-d(intraseasonal)] accounted for the majority(63%) of the EPEs, and the precipitation intensity on the peak wet day was larger th...  相似文献   

The climate change research that makes the front page: Is it fit to engage societal action?     

《Global Environmental Change》2023

By growing awareness for and interest in climate change, media coverage enlarges the window of opportunity by which research can engage individuals and collectives in climate actions. However, we question whether the climate change research that gets mediatized is fit for this challenge. From a survey of the 51,230 scientific articles published in 2020 on climate change, we show that the news media preferentially publicizes research outputs found in multidisciplinary journals and journals perceived as top-tier. An in-depth analysis of the content of the top-100 mediatized papers, in comparison to a random subset, reveals that news media showcases a narrow and limited facet of climate change knowledge (i.e., natural science and health). News media selectivity reduces climate change research to the role of a sentinel and whistleblower for the large-scale, observed, or end-of-century consequences of climate change for natural Earth system components. The social, economic, technological, and energy aspects of climate change are curtailed through mediatization, as well as local and short-term scales of processes and solutions. Reviewing the social psychological mechanisms that underlie behavioral change, we challenge the current criteria used to judge newsworthiness and argue that the consequent mediatization of climate change research fails to breed real society engagement in actions. A transformative agenda for the mediatization of climate change research implies aligning newsworthiness with news effectiveness, i.e., addressing the extent to which communication is effective in presenting research that is likely to produce behavioral change.  相似文献   

An analysis of the action of dowels on the stabilization of rock blocks on underground excavation walls   总被引：1，自引：1，他引：0  

P. P. Oreste  M. Cravero 《Rock Mechanics and Rock Engineering》2008,41(6):835-868

Summary  Underground excavation in fractured rock masses can lead to instability of rock blocks on its perimeter. Among the stabilization measures that are often used, dowels or passive bolts play an important role. These passive reinforcement measures cannot, however, be easily considered in simplified calculation techniques based on the Limit Equilibrium Method (LEM). The analysis of such elements cannot be separated from rock-dowel interaction following the displacement of the block. A new simplified calculation procedure is presented in this paper for the analysis of the interaction between rock and dowels on walls of an underground excavation where potentially sliding rock blocks are present. The assumed interaction scheme is, however, partial in that dowel reinforcement is only activated by a small displacement, while this displacement does not induce a destressing of the rock block. Such a procedure allows a fast dimensioning of the dowels, considering the maximum stabilizing force that they are able to apply to the block without reaching a critical condition with reference to dowel failure or to its connection to the rock. Correspondence: Dr. Pierpaolo Oreste, Politecnico di Torino, DITAG, C. so Duca degli Abruzzi 24, 10129 Torino, Italy  相似文献   

基于nu-SVR的网络RTK综合误差模型     

王新洲  舒海翅 《武汉大学学报(信息科学版)》2008,33(2):177-179,202

综合利用网络RTK中所有基准站的误差信息,在网络RTK系统的覆盖范围内,用支持向量机中的nu-SVR方法建立了一个统一的综合误差模型,并根据此综合误差模型直接改正流动站的实测数据.建模分析表明,采用该方法能获得较好的流动站定位结果.  相似文献   

人文与经济地理学的传承与创新：青年学者的行动     

陈明星  陆大道  唐常春  刘承良  叶玉瑶  丁建军  王姣娥  刘晔  唐志鹏  孙中伟  陈东  李钢  孙伟  李鹤  潘峰华  张圆刚  李玉恒  李裕瑞  魏冶  赵建吉  彭立  高菠阳  胡志丁  钱丽芸  姜炎鹏  董冠鹏  杨传开  虞虎  安宁  戚伟 《地理研究》2018,37(10):2096-2124

2018年是中国改革开放40周年,也是“科学的春天”40周年。随着中国进入特色社会主义新时代,人文与经济地理学也将迈入新时代。青年学者恰好处在承前启后的这一时期,围绕学科传承和创新发展需要,面向新时代国家和经济社会发展的现实需求,青年学者积极行动起来,努力学习和传承人文与经济地理学前辈所建立的学科体系,并力图继续开拓和创新。一是助力建设学科文化,打造具有学科认同感和归属感的学术共同体。二是在向西方学习的同时,加强中国特色的自主理论建构与创新。三是向相关学科方向学习,加强交叉与综合的数据和方法创新,建设科学化、多元化的研究方法体系。四是青年学者更需要踏实认真的态度,找准个人研究领域方向,求真务实并力图创造新的知识,不断提升研究深度。人文与经济地理学的学科梦必将在一代代青年学者的接力奋斗中变为现实。  相似文献   

The influence of social movements on policies that constrain fossil fuel supply     

Georgia Piggot 《Climate Policy》2018,18(7):942-954

Mounting evidence suggests that a large portion of the world's fossil fuel reserves will have to remain in the ground to prevent dangerous climate change. Yet, the fossil fuel industry continues to invest in new infrastructure to expand fuel supply. There appears to be a prevailing logic that extraction is inevitable, in spite of growing climate change concerns. Few political leaders seem to be willing to challenge this logic. The absence of adequate political action on climate change has sparked a burgeoning social movement focused on constraining fossil fuel supply. This article describes this movement, and explores the role that social mobilization may play in enabling policies that limit fossil fuel extraction. Drawing from literature on social mobilization and political change, this work: (1) discusses some of the social and political barriers to mobilization focused on restricting fossil fuel supply; (2) describes the pathways through which mobilization efforts may influence climate policy; and (3) highlights insights from studies of successful social movements that have relevance for the issue of fossil fuel extraction. The article concludes with directions for future research on social mobilization focused on supply-side climate policy.

Key policy insights

• Enacting policies to limit fossil fuel supply has proven challenging in many contexts.

• There is renewed interest in the role social movements may play in shifting the political landscape, to make it more likely that policies to restrict fossil fuel extraction may succeed.

• Effective social mobilization requires a combination factors aligning at the right time to influence policy outcomes, such as windows of political opportunity opening, and compelling framing that calls citizens to action.

• Critical examination of the factors that lead to movement success is necessary to understand the circumstances where social mobilization may influence supply-side climate policies.

  相似文献