21世纪平流层温度变化和臭氧恢复

温室气体增加和可能的臭氧恢复将是影响21世纪平流层温度变化的两个主要因素。温室气体增加的辐射效应将导致平流层变冷,而臭氧恢复将导致平流层变暖。为探讨平流层温度在这两种相反因素作用下的变化趋势,研究中使用了观测的臭氧和温度资料以及4个有代表性的IPCC-AR4海气耦合的全球环流模式的模拟结果(GISS-ER、GFDL-CM20、NCAR-CC-SM3和UKMO-HadCM3)。观测分析结果表明,在近10年来臭氧柱含量和平流层低层温度均有升高的趋势,平流层中层温度仍然延续20世纪后20年的变冷趋势。IPCC-AR4的模拟结果表明,单纯温室气体增加将造成平流层变冷。可是,在同时考虑温室气体增加和臭氧层恢复的情况下,模拟结果表明平流层中上层仍将维持变冷的趋势,而下层则存在变暖的趋势,但几个模式给出的变暖趋势有差别。UKMO-HadCM3给出的模拟结果是在3种温室气体排放情况下平流层低层均呈现较强的变暖趋势,变暖的层次可达40hPa;GFDL-CM20和NCAR-CCSM3给出的变暖趋势较弱一些,并且变暖主要位于60hPa以下的层次。     

湖南省矿山生态环境污染防治现状及其恢复治理研究

简述了湖南省矿山生态环境污染破坏的现状,即矿业废水、废气、废渣污染,矿山开采以及由其引发的次生地质灾害对土地的占用和对植被的破坏等;介绍了湖南省短期(2003～2010年)和长期(2010～2015年)恢复治理的重点区域、重点工程以及实现矿山生态环境保护与恢复治理任务所需要的政策措施和技术措施.     

Economic Critical Resources for the Industrial Exploitation of Natural Gas Hydrate

Since the implementation of several pilot production tests were in natural gas hydrate (NGH) reservoirs in terrestrial and marine settings, the study of NGH has entered a new stage of technological development for industrial exploitation. Prior to the industrial exploitation of any given NGH reservoir, the economic feasibility should be examined. The first step of economic evaluation of a NGH reservoir is to know whether its resource amount meets the requirement for industrial exploitation. Unfortunately, few relevant studies have been conducted in this regard. In this study, the net present value (NPV) method is employed to estimate the economic critical resources required for the industrial exploitation of NGHs under different production scenarios. Sensitivity analysis is also performed in order to specify the effects of key factors, such as the number of production wells, gas price, technological improvement and tax incentive, on the economic critical resources. The results indicate that China requires the lowest economic critical resource for a NGH reservoir to be industrially exploited, ranging from 3.62 to 24.02 billion m3 methane. Changes in gas price and tax incentives also play significant roles in affecting the threshold and timeline for the industrial exploitation of NGH.     

地形特征约束下的失真DEM修复方法

数字高程模型（DEM）在描述地形时会存在一定程度的失真现象,对失真DEM进行修复可以有效地提高其精度及保真度。本文针对DEM在描述规则地形时存在的失真现象,提出了用地形特征约束失真DEM形态结构的失真修复方法,以规则地形中的平地结构地形为例,进行了失真修复试验。首先根据地形特征确定平地地形的DEM应为平面结构,再采用最小二乘法（LS）及随机抽样一致性算法（RANSAC）对其平面方程进行参数估计,进而得到修复的DEM数据。试验结果表明,本文所提的修复方法有效可行,修复后的DEM数据不仅提高了精度,还能充分地反映原地形的地形特征。两种修复算法的修复能力相接近,当存在大量格网点时,都能达到很好的修复效果,但RANSAC更能适应高程异常的情况,鲁棒性更好。     

Touristic disaster: Spectacle and recovery in Post-Katrina New Orleans

This paper develops the concept touristic disaster as a heuristic device to examine the conflictual and contradictory aspects of showcasing disaster-devastated neighborhoods as tourist attractions. Touristic disaster refers to the application of tourism modes of staging, visualization, and discourse to reenchant the money making deterrents (stigma) of “destruction” and “ruin” and re-signify disaster to indicate “recovery” and “rebirth.” This paper uses empirical examples from New Orleans to examine the transition from “disaster tourism” to “recovery tourism” in tourism framings of post-Katrina rebuilding. The concept of touristic disaster views disaster-devastated neighborhoods as sites and arenas of contestation in which opposing groups and interests battle to control representations of urban space. The paper illustrates the motivations, processes, and paradoxical impacts of the commodification and global representation of “disaster” and “recovery” and provides insights into the ways in which people can use spectacle to contest marginalization.     

Safety and CO2 emissions: Implications of using organic fluids in a ship’s waste heat recovery system

This paper considers the practical application of exhaust gas waste heat recovery from the main engines of merchant ships. A water-based Rankine Cycle is used as a baseline and this is compared with five organic Rankine cycle systems using benzene, heptane, hexamethyldisiloxane, toluene and R245fa. The thermodynamic model of the waste heat recovery system is described. This is then applied in a case study utilising an Aframax tanker. The case study allows the comparison of the different waste heat recovery systems in more realistic scenarios. The efficiency of the different systems is compared as well as their potential to reduce CO₂ emissions, ship impact, and economic viability are also discussed. The paper closes with consideration of the safety and regulatory issues associated with the use of organic fluids in the marine environment.     

TJ-1模拟月壤承载特性室内试验研究

本研究自行设计加工了一套可以实现位移速率控制的加载装置,采用TJ-1模拟月壤为地基材料,把着陆器足垫作为基础进行了位移速率控制条件下的载荷模型试验,并采用了3种不同方法计算足垫基底的平均应力。通过对试验结果的分析对比得出以下主要结论：足垫的地基承载力和变形模量随加载速率大致呈线性增加,按足垫与地基的实际接触面积计算的极限承载力稍大于按足垫最大上口面积计算得到的地基承载力。考虑到安全储备建议采用按最大上口面积计算所得地基承载力。足垫基础下按实际接触面积计算得到的变形模量介于按足垫最小底面和最大上口面面积计算的结果之间。     

Spectral mixture analysis to assess post-fire vegetation regeneration using Landsat Thematic Mapper imagery: Accounting for soil brightness variation

Post-fire vegetation cover is a crucial parameter in rangeland management. This study aims to assess the post-fire vegetation recovery 3 years after the large 2007 Peloponnese (Greece) wildfires. Post-fire recovery landscapes typically are mixed vegetation-substrate environments which makes spectral mixture analysis (SMA) a very effective tool to derive fractional vegetation cover maps. Using a combination of field and simulation techniques this study aimed to account for the impact of background brightness variability on SMA model performance. The field data consisted out of a spectral library of in situ measured reflectance signals of vegetation and substrate and 78 line transect plots. In addition, a Landsat Thematic Mapper (TM) scene was employed in the study. A simple SMA, in which each constituting terrain feature is represented by its mean spectral signature, a multiple endmember SMA (MESMA) and a segmented SMA, which accounts for soil brightness variations by forcing the substrate endmember choice based on ancillary data (lithological map), were applied. In the study area two main spectrally different lithological units were present: relatively bright limestone and relatively dark flysch (sand-siltstone). Although the simple SMA model resulted in reasonable regression fits for the flysch and limestones subsets separately (coefficient of determination R² of respectively 0.67 and 0.72 between field and TM data), the performance of the regression model on the pooled dataset was considerably weaker (R² = 0.65). Moreover, the regression lines significantly diverged among the different subsets leading to systematic over-or underestimations of the vegetative fraction depending on the substrate type. MESMA did not solve the endmember variability issue. The MESMA model did not manage to select the proper substrate spectrum on a reliable basis due to the lack of shape differences between the flysch and limestone spectra,. The segmented SMA model which accounts for soil brightness variations minimized the variability problems. Compared to the simple SMA and MESMA models, the segmented SMA resulted in a higher overall correlation (R² = 0.70), its regression slope and intercept were more similar among the different substrate types and its resulting regression lines more closely resembled the expected one-one line. This paper demonstrates the improvement of a segmented approach in accounting for soil brightness variations in estimating vegetative cover using SMA. However, further research is required to evaluate the model's performance for other soil types, with other image data and at different post-fire timings.     

基于16QAM信号星座点判决域切换的混合正方形轮廓线算法

提出了一种基于16QAM信号星座点判决域切换的混合正方形轮廓线算法.该算法通过判决输出信号是否在星座点判决域内,在正方形轮廓线算法和判决导引算法之间进行切换,不仅能够对输出信号进行相位恢复,而且可以得到更小的剩余码间干扰.水声信道仿真结果表明:与传统的正方形轮廓线算法相比,混合正方形轮廓线算法的码间干扰更低,输出星座点更紧凑,对水声信道具有良好的均衡能力.     

论中国城市生态健康与环境污染修复

从大气污染、水体污染、固体废弃物污染、噪声污染和土壤污染体等方面,对中国城市生态健康面I临的问题和环境污染现状进行了分析研究。结果表明,城市环境污染形势依然严峻,城市生态健康受到严重威胁,日益成为制约城市健康发展的主要因素。在此基础上,提出了中国城市环境污染修复的建议,认为保持生态健康,城市环境污染的物理和化学修复措施结合生物修复,是构成生态修复的重要要素。在实际修复过程中,把物理修复、化学修复和生物修复更好地结合起来,才能形成有效的生态修复技术。应该进一步增强城市生态健康意识,复合的城市生态系统还需用系统、生态的方法对城市环境污染进行修复,以实现可持续发展和构建和谐社会。