黄海海洋环境调查及其主要结果     

孙湘平  汤毓祥 《海洋科学进展》1993,(3)

本文系将我国几十年来在黄海、渤海和东海北部,开展海洋环境调查的情况与主要结果,作一简要回顾。  相似文献   

Degradation of rope properties under increasing monotonic load     

Juan Felipe Beltran  Eric B. Williamson 《Ocean Engineering》2005,32(7):826-844

This paper describes the development of a computational model to predict the response of synthetic-fiber ropes under both monotonic and cyclic loads. The model addresses the issue of damage to a rope cross-section and its effect on rope response. Isotropic damage is assumed and is therefore characterized by a scalar quantity known as the damage index. The damage index is used to quantify the amount of deterioration that takes place in a damaged rope throughout its loading history. For the current study, data obtained from static tension tests are used to determine the evolution relationship for the damage index. This relationship is based on the stiffness ratio between experimental data and simulation of rope response without any source of damage and is assumed to be described by an exponential equation. Numerical simulations of damaged rope behavior compare well with experimental results.  相似文献   

Two decades of measuring environmental attitudes: A comparative analysis of 33 countries     

Axel Franzen  Dominikus Vogl 《Global Environmental Change》2013,23(5):1001-1008

This paper analyzes the development of environmental concern by using the three waves of the environmental modules of the International Social Survey Programme. First, we discuss the measurement of environmental concern and construct a ranking of countries according to the new 2010 results. Second, we analyze the determinants of environmental concern by employing multilevel models that take individual as well as context effects into account. Third, we explore the longitudinal aspect of the data at the macro level in order to uncover the causal relation between countries’ wealth and environmental concern. The results show that environmental concern is closely correlated with the wealth of the nations. However, environmental concern decreased in almost all nations slightly during the last two decades. The decline was lower in countries with improving economic conditions suggesting that economic growth helps to maintain higher levels of environmental concern.  相似文献   

Who remembers a hot summer or a cold winter? The asymmetric effect of beliefs about global warming on perceptions of local climate conditions in the U.S.     

Peter D. Howe  Anthony Leiserowitz 《Global Environmental Change》2013,23(6):1488-1500

This paper explores the phenomenon of local climate perception and the extent to which public perceptions match climate conditions as recorded in instrumental climate data. We further examine whether perceptions of changes in local climates are influenced by prior beliefs about global warming, through the process of motivated reasoning. Using national survey data collected in the United States in 2011, we find that subjective experiences of seasonal average temperature and precipitation during the previous winter and summer were related to recorded conditions during each season. Beliefs about global warming also had significant effects on subjective experiences with above-normal temperatures, particularly among those who believed that global warming is not happening. When asked about the summer of 2010, those who believed that global warming is not happening were significantly less likely to report that they had experienced a warmer-than-normal summer, even when controlling for demographics and local climate conditions. These results suggest that the subjective experience of local climate change is dependent not only on external climate conditions, but also on individual beliefs, with perceptions apparently biased by prior beliefs about global warming.  相似文献   

Fault seal prediction of seismic-scale normal faults in porous sandstone: A case study from the eastern Gulf of Suez rift,Egypt     

Christian Tueckmantel  Quentin J. Fisher  Rob J. Knipe  Henry Lickorish  Samir M. Khalil 《Marine and Petroleum Geology》2010

A study of normal faults in the Nubian Sandstone Sequence, from the eastern Gulf of Suez rift, has been conducted to investigate the relationship between the microstructure and petrophysical properties of cataclasites developed along seismic-scale faults (slip-surface cataclasites) and smaller displacement faults (deformation bands) found in their damage zones. The results help to quantify the uncertainty associated with predicting the fluid flow behaviour of seismic-scale faults by analysing small faults recovered from core, a common procedure in the petroleum industry. The microstructure of the cataclasites was analysed as well as their single-phase permeability and threshold pressure. Faulting occurred at a maximum burial depth of ∼1.2 km. The permeability of deformation band and slip-surface cataclasites varies over ∼1.5 orders of magnitude for a given fault. Our results suggest that the lowest measured deformation band permeabilities provide a good estimate for the arithmetic-mean permeability of the major slip-surface cataclasites. This is because the cataclastic permeability reduction is mostly established early in the deformation history. Stress at the time of faulting rather than final strain appears to be the critical factor determining fault rock permeability. For viable predictions it is important that the slip-surface cataclasites and deformation bands originate from the same host. On the other hand, a higher uncertainty is associated with threshold pressure predictions, as the arithmetic-mean slip-surface cataclasite threshold pressure exceeds the highest measured deformation band threshold pressure by at least a factor of 4.  相似文献   

Influence of damage on pore size distribution and permeability of rocks     

Chloé Arson  Jean‐Michel Pereira 《国际地质力学数值与分析法杂志》2013,37(8):810-831

The model proposed in this article relates permeability to porosity measurements that can easily be performed in the laboratory. The pore size distribution (PSD) curve is updated with strains and damage. The updated volumetric fractions of natural pores and cracks are introduced in the expression of permeability. Contrary to classical permeability models based on PSD integrations, the model proposed in this article accounts for possible changes in the porosity modes: one mode for undamaged samples and two modes for cracked samples. The proposed approach also accounts for varying states of damage, as opposed to classical fracture network models, in which the cracks pattern is fixed. The only material parameters that are required to describe the microstructure are the lower and upper bounds of the pores size for both natural pores and cracks. All the other PSD parameters involved in the model are related to macroscopic parameters that can easily be determined in the laboratory, such as the initial void ratio. The framework proposed in this article can be used in any damage constitutive model to determine the permeability of a brittle porous medium. Drained triaxial compression tests have been simulated. Before cracks initiation, permeability decreases while the larger natural pores are getting squeezed. After the occurrence of damage, permeability grows due to the increase of cracks density. The model performs well to represent the influence of the confining pressure on damage evolution and permeability variations. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

20世纪50年代初地质机构变革的考证和思考     

耿元生 《地质论评》2022,68(5):2022092004-2022092004

原中央地质调查所、中央研究院地质研究所和资源委员会矿产测勘处都曾为中国地质事业的发展作出过重要贡献。但是,在1949年以前总体地质人员少、部门分散。为解决解放初期矿产资源紧缺和地质人员短缺的矛盾,1950年8月经政务院批准成立了中国地质工作计划指导委员会,及其领导下的矿产地质勘探局、中国科学院地质研究所和古生物研究所,开始了地质界一元化的机构改革。1951年5月7日新成立的三个机构开始运行,在运行初期实行地质研究人员的双重身份制度,即在矿产地质勘探局为技正,在研究所为研究员。1952年6月初步确定了各单位内设机构和人员,同时各专业地质队陆续成立,开始了人员的再次分配。1952年8月地质部成立,矿产地质勘探局,逐步转变为地质部的不同部门,地质研究所和古生物研究所全面接受地质部的领导。原中央地质调查所在这次变革中人员被分散到新成立的三个部门和有关单位,原来的内设机构被彻底分解,事实上被撤销。原中央地质调查所在长期实践中形成了以调查为本、调查与研究紧密相结合的研究风格和特色,在解放初期,不论是矿产地质勘探局还是中科院地质研究所和古生物研究所都围绕国家急需的矿产资源开展工作,都谈不上与中央地质调查所的机构传承关系。  相似文献   

基于核磁共振的不同含水率黄土古土壤冻融循环试验研究     

叶万军  强艳红  景宏君  邹愈 《工程地质学报》2022,30(1):144-153

为明确不同含水率古土壤在冻融循环作用下其微观结构特性及古土壤损伤机制,采用核磁共振扫描仪对不同含水率冻融循环后的古土壤试样进行测试,研究冻融循环和含水率共同作用对古土壤微观结构的影响及土体内部损伤变化。结果表明:冻融循环下不同含水率使土体内部产生不同程度的损伤,损伤程度为含水率大的土体大于含水率小的土体。随着冻融循环次数增加,T₂谱曲线信号幅度增加,孔隙结构改变,大孔隙、最大孔隙含量增加,中孔隙含量减小; 同时含水率较大的土体孔隙体积增大幅度大于含水率较小的土体,说明在季节冻土区建设工程中含水率越大土体越易发生破坏,因此在工程中应注意防排水问题。依据损伤力学原理,得出土体颗粒连续性与孔隙率关系,进而得出有效应力与孔隙率关系; 根据核磁扫描结果,建立孔隙率与冻融循环次数关系,最终推导出古土壤有效应力与冻融循环次数关系表达式。研究成果为季节冻土区古土壤地层建设工程提供理论指导。  相似文献   

One thousand ways to experience loss: A systematic analysis of climate-related intangible harm from around the world     

《Global Environmental Change》2019

A situated and socially engaged science of loss arising from climate change takes people’s lived experiences with risk and harm as its fundamental starting point. It foregrounds what losses occur, where and how, which of these losses matter most to people and why, and whether or not such losses are considered acceptable and potentially reversible. However, obtaining such insight is difficult if the many things people value, across space and time, are intangible, i.e. they cannot and perhaps should not be quantified, and hence are often overlooked and omitted. This is the case, for instance, for the symbolic and affective dimensions of culture and place, such as sense of belonging, personal and collective notions of identity, and ways of knowing and making sense of the world, all of which are already undermined by climate change. Here, we perform the first systematic comparative analysis of people-centered and place-specific experiences with climate-related harm to people’s values that are largely intangible and non-commensurable. We draw upon >100 published case studies from around the world to make visible and concrete what matters most to people and what is at stake in the context of climate-related hazards and impacts. We show that the same threats can produce vastly different outcomes, ranging from reversible damages to irreversible losses and anticipated future risks, across numerous value dimensions, for indigenous and non-indigenous families, communities, and countries at all levels of development. Through this analysis, we also empirically validate dimensions of harm that have been produced and reproduced in the literature, albeit often devoid of distinct substance, lived experiences, and intrinsic significance. We end by discussing ethical implications of the ‘one thousand ways’ to encounter harm and offer recommendations to overcome methodological challenges in advancing a science of loss grounded in place.  相似文献   

农商部地质调查局始末考     

杨丽娟 《地质论评》2021,67(4):67041192-67041197

中国地质调查事业始于民国。1913年地质调查所正式成立,直至1950年裁撤,30余年间一直是中国地质学家的大本营。1916年初,地质调查所重新改组为地质调查局,并在行政上直接隶属农商部。同年夏天,地质研究所学生毕业后入地质调查局工作,成为地质调查局主要成员。1916年底,地质调查局被裁撤,又恢复地质调查所,但此后工作形式与机构管理均与调查局时期无太大变化。地质调查局因存在时间较短,加之史料不多,以往著述着墨不多。本文以《农商公报》、《政府公报》及地质调查局相关原始材料为基础,考察地质调查局成立始末、机构设置、人员组成及早期进行的地质调查工作。认为地质调查局的成立是中国地质学者建立独立地质调查专门机构的一次尝试。  相似文献