黄土地区场地的地震地面运动参数特征

结合近年来中国西部黄土地区城市或厂矿企业地震小区划和岩土地震工程的最新研究成果,归纳分析了黄土的波速特征和非线性特征．结合实例阐述了影响黄土地区地震地面运动参数的主要因素．     

The effects of LNG-tank sloshing on the global motions of LNG carriers

The coupling and interactions between ship motion and inner-tank sloshing are investigated by a time-domain simulation scheme. For the time-domain simulation, the hydrodynamic coefficients and wave forces are obtained by a potential-thoery-based three-dimensional (3D) diffraction/radiation panel program in frequency domain. Then, the corresponding simulations of motions in time domain are carried out using convolution integral. The liquid sloshing in a tank is simulated in time domain by a Navier–Stokes solver. A finite difference method with SURF scheme is applied for the direct simulation of liquid sloshing. The computed sloshing force and moment are then applied as external excitations to the ship motion. The calculated ship motion is in turn inputted as the excitation for liquid sloshing, which is repeated for the ensuing time steps. For comparison, we independently developed a coupling scheme in the frequency domain using a sloshing code based on the linear potential theory. The hydrodynamic coefficients of the inner tanks are also obtained by a 3D panel program. The developed schemes are applied to a barge-type FPSO hull equipped with two partially filled tanks. The time-domain simulation results show similar trend when compared with MARIN's experimental results. The most pronounced coupling effects are the shift or split of peak-motion frequencies. It is also found that the pattern of coupling effects between vessel motion and liquid sloshing appreciably changes with filling level. The independent frequency-domain coupled analysis also shows the observed phenomena.     

Variation reduction in quality of an optical triangulation system employed for underwater range finding

This paper attempts to more thoroughly understand the factor effects on the performance of an optical triangulation system used for range finding in water. In this study analytical expressions for estimating the peak of the laser spot and for image processing were presented. Both the design of experiment process and the Taguchi method have been used to evaluate factor effects and to specify design parameters. To assess the effects of monochrome and color image displays on the performance of range finding, two sets of experiments were carried out. The optimum models based on factor effects were predicted and constructed through the analysis of variance. The confirmation experiments were performed and the outcomes are in good agreement with the predicted optima. Based upon the results of experiments and analyses, it is found that brightness, contrast, and peak detection algorithms are the main factors to dominate the quality of range finding while using a monochrome camera. And further, all control factors of brightness, contrast, peak detection algorithm, sampling range, and specific primary color for intensity computation are critical to the quality of range finding while using a color camera. Notably, right selections of the image resolution and the sampling range can shorten the computing time and get high precision results.     

Economic vulnerability to Peak Oil

Peak Oil, which refers to the maximum possible global oil production rate, is increasingly gaining attention in both science and policy discourses. However, little is known about how this phenomenon will impact economies, despite its apparent imminence and potential dangers. In this paper, we construct a vulnerability map of the U.S. economy, combining two approaches for analyzing economic systems, i.e. input–output analysis and social network analysis (applied to economic data). Our approach reveals the relative importance of individual economic sectors, and how vulnerable they are to oil price shocks. As such, our dual-analysis helps identify which sectors, due to their strategic position, could put the entire U.S. economy at risk from Peak Oil. For the U.S., such sectors would include Iron Mills, Fertilizer Production and Transport by Air. Our findings thus provide early warnings to downstream companies about potential ‘trouble’ in their supply chain, and inform policy action for Peak Oil. Although our analysis is embedded in a Peak Oil narrative, it is just as valid and useful in the context of developing a climate roadmap toward a low carbon economy.     

The ‘oil vulnerability’ of commuter patterns: A case study from Yorkshire and the Humber,UK

Motorised transport infrastructure and increasingly specialised labour markets have resulted in energy intensive commuter patterns in many parts of the world. This is cause for concern due to the possibility of oil price shocks and the need to restrict the combustion of fossil fuels to minimise the chances of runaway climate change. The paper investigates methods to identify the spatial distribution and socio-demographic profiles of those who are vulnerable to high oil prices. It does this by use of four metrics of oil vulnerability which were developed using a spatial microsimulation model and applied to the case study region of Yorkshire and the Humber, UK. The metrics capture different aspects of vulnerability and highlight the importance of translating conceptual definitions into practical metrics. The geographically aggregated results coincide with the literature: rural areas are associated with the highest levels of vulnerability. The individual level results indicate that vulnerability can be prevalent even in seemingly resilient areas. Ultimately, we conclude that the social and spatial distribution of oil vulnerability depends on how an energy-constrained future is envisioned. Creating localised metrics about the future is a challenging task fraught with danger but could, provided that these metrics are interpreted with sufficient humility, aid the development of equitable policies to encourage resilience, as part of a worldwide transition away from fossil fuels.     

Eco-localisation as a progressive response to peak oil and climate change - A sympathetic critique

This paper critically but sympathetically examines eco-localisation as a response to ‘peak oil’ and to reduce the emission of CO₂ to avoid dangerous climate change. Rather than seeing the politics of climate change and peak oil as in some way ‘post-political’, the paper argues that protagonists of localised economies are developing radical new conceptions of livelihood and economy that directly cut against the logic of growth-based capitalist economic strategies and elite conceptualisations of economic development. Building on development theory, the paper develops a conceptualisation of ‘immanent’ and ‘intentional’ localisation, with the former a simple move by businesses of economic activities that have high transport costs closer to their markets. Advocates of intentional localisation are working more pro actively at grassroots level to develop local solutions to peak oil and climate change based on developing less resource-intensive yet enjoyable and fulfilling livelihoods in more localised economies. In discussing the contested nature of localisation, the paper engages with critiques of eco-localisation from neoliberal advocates and from the left, before concluding that localisation should be seen more as a different calculation of where economic activities would be located, which aims to reduce oil consumption and CO₂ emissions, rather than a call for autarky. The paper concludes by arguing that analyses of the scale of economic networks need to pay more attention of the materiality of oil consumption and CO₂ emissions, and that scales cannot be seen as socially constructed.     

Geographies of peak oil: The other carbon problem

This extended editorial introduction to a themed issue of Geoforum on geographies of peak oil has three objectives. First, it provides a concise account of the ’peak oil’ claim, identifying the key protagonists in the debate, and outlining different stances with regard to the timing, shape and composition (conventional vs. non-conventional hydrocarbons) of the peak. Second, after briefly characterising the limited engagement with peak oil by human geographers, it offers a provisional set of claims about what a geographical analysis of peak oil might yield. Finally, it introduces each of the papers and, in doing so, makes the case for a fuller and more sustained engagement by geography with this ’other carbon problem.’     

博格达峰地区气候变化特征及其对冰川变化的影响

20世纪中叶以来,随着全球变暖加剧,中国冰川普遍发生了退缩,对局地人民生活、生存环境及社会经济产生了深刻的影响,对位于西北干旱区的博格达峰地区尤为突出.本文首先采用趋势分析、突变检验和小波变换等方法对研究区周边气温、降水进行研究,同时应用Landsat l-4、5、7MSS、TM/ETM+影像分析1972-2013年博格达峰区冰川变化特征,在此基础上系统探讨冰川变化与该区气候变化之间的响应关系.结果表明:①1960-2013年研究区气温、降水变化倾向分别为0.19℃/10 a和12.4 mm/l0 a;年平均气温在1990年前后存在显著突变,年降水量在1985年前后存在突变.气温主要表现为8～10 a的周期,降水周期性较差.目前处于气温偏高、降水偏少期;②1972-2013年冰川面积减少46.71±1.32 km2,年均退缩率为0.66％±0.02％,冰川退缩趋势明显.其中1972-1990年,冰川年均退缩率为0.44％±0.03％;近20年来冰川退缩加剧,年均退缩率达到0.78％±0.09％;③通过分形理论对研究区冰川空间结构特征分析表明,预计未来冰川消融率将趋于稳定,但仍处于较高状态;④对比中国西部各地区冰川的变化,发现该地区冰川退缩和其他区域退缩速率相吻合;⑤1990年之前博格达峰地区冰川变化受温度和降水共同控制,1990年之后冰川退缩主要由气温上升引起.     

甘肃地区三水准超越概率水平地震动峰值加速度关系与场地放大效应研究

通过对甘肃省158个场地安全性评价结果的分析,讨论了不同的超越概率下水平地震动峰值加速度之间的关系以及不同的场地条件对基岩峰值加速度的放大效应。结果对甘肃地区地震安全性评价中水平地震动峰值加速度的取值提供必要的参考。     

应用动态复合震源模型模拟汶川Mw7.9地震强地面运动

2008年5月12日中国汶川地区发生Mw7.9地震,震中位置103.4°E,31.0°N.主要发震断层空间展布长达300多公里,由南西方向到北东方向呈现明显的分段性,汶川一映秀段逆冲为主兼有少量的右旋走滑分量;安县一北川段为逆冲一右旋走滑的断层错动;青川段以右旋走滑为主兼有少量逆冲分量.采用改进后的复合震源强地面运动预...