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141.
针对公共安全突发事件应急救援的封闭空间场景(Confined Space Scene,CSS)信息采集不通畅、不全面而影响救援等问题,提出1种基于不变特征转换(Scale invariant feature transform,SIFT)和支持向量机(Support Vector Machine,SVM)的图像信息异常检测方法。在场景内外信息传递“断环”情况下,该方法可利用物联网技术采集的图片,或以网络图片信息、历史类似场景数据等作为补充,通过SIFT特征提取、K means聚类处理以及SVM分类,实现场景的智能识别。经仿真分析,该方法能实现封闭空间内外部图像信息互通,“接补”因无法了解事件内部情况而产生的救援环节链条的“断环”,为救援提供决策参考。 相似文献
142.
The present study was conducted to compare the 137Cs, 40K, 232Th, and 238U activity concentrations in epigeic moss (Hypnum cupressiforme) and lichen (Cladonia rangiformis). The activity levels in 37 moss and 38 lichen samples collected from the Marmara region of Turkey were measured using a gamma spectrometer equipped with a high purity germanium (HPGe) detector. The activity concentrations of 137Cs, 40K, 232Th, and 238U in the moss samples were found to be in the range of 0.36-8.13, 17.1-181.1, 1.51-6.17, and 0.87-6.70 Bq kg−1 respectively, while these values were below detection limit (BDL)-4.32, 16.6-240.0, 1.32-6.47, and BDL-3.57 Bq kg−1 respectively in lichen. The average moss/lichen activity ratios of 137Cs, 40K, 232Th, and 238U were found to be 1.32 ± 0.57, 2.79 ± 1.67, 2.11 ± 0.82, and 2.19 ± 1.02, respectively. Very low 137Cs concentrations were observed in moss and lichen samples compared to soil samples collected from the same locations in a previous study. Seasonal variations of the measured radionuclide activities were also examined in the three sampling stations. 相似文献
143.
After a prolonged drafting and consultation process, South Africa has introduced a new royalty charge to holders of mineral development rights. Deciding on an acceptable royalty is a complex process, especially when it targets deceptive economic rents. This is achieved with a variable royalty rate that slides in tandem with mine profitability. The base is sales revenue and to compensate for the need to charge for the mineral in its unprocessed form, refined production is charged at a lower rate. The aim of this paper is to discuss the Royalty Act in the context of its background, the underlying theory and fundamental principles. This paper argues that the fundamental principles on which the Act is based are sound, but raises a concern on potentially high compliance and reporting costs. 相似文献
144.
Anjos RM Juri Ayub J Cid AS Cardoso R Lacerda T 《Journal of environmental radioactivity》2011,102(11):1055-1061
Health hazard from natural radioactivity in Brazilian granites, covering the walls and floor in a typical dwelling room, was assessed by indirect methods to predict external gamma-ray dose rates and radon concentrations. The gamma-ray dose rate was estimated by a Monte Carlo simulation method and validated by in-situ measurements with a NaI spectrometer. Activity concentrations of 232Th, 226Ra, and 40K in an extensive selection of Brazilian commercial granite samples measured by using gamma-ray spectrometry were found to be 4.5-450 Bq kg−1, 4.9-160 Bq kg−1 and 190-2029 Bq kg−1, respectively. The maximum external gamma-ray dose rate from floor and walls covered with the Brazilian granites in the typical dwelling room (5.0 m × 4.0 m area, 2.8 m height) was found to be 120 nGy h−1, which is comparable with the average worldwide exposure to external terrestrial radiation of 80 nGy h−1 due to natural sources, proposed by United Nations Scientific Committee on the Effects of Atomic Radiation. Radon concentrations in the room were also estimated by a simple mass balance equation and exhalation rates calculated from the measured values of 226Ra concentrations and the material properties. The results showed that the radon concentration in the room ventilated adequately (0.5 h−1) will be lower than 100 Bq m−3, value recommended as a reference level by the World Health Organization. 相似文献
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Kim N 《Disasters》2012,36(2):195-211
This paper proposes a simple indicator to measure the exposure to natural disasters for the poor and non-poor population, in order to assess the global and regional trend of natural hazard and poverty. Globally, poor people are two times more exposed to natural disasters than the non-poor in the twenty-first century. The time trend varies across regions, with poor people in East Asia and Pacific being most exposed to natural disasters, followed by those in South Asia and Sub-Saharan Africa. The change of exposure measure over time is decomposed into two factors: a pure exposure change, which could be fuelled by climate change; and a concentration component. The result shows that the total net increase of exposure between the 1970s and the 2000s is driven significantly by the increased concentration of the poor (26 per cent) in disaster-prone areas, whereas the contribution of that factor remains very small for the non-poor (six per cent). 相似文献
148.
采用一维土柱装置模拟非水相液体(NAPLs)在我国两种典型土壤(北京潮土与湖南红壤)中的垂向迁移过程,以甲苯为例研究了其在两种土壤中的迁移性能;采用XRD技术测定土壤的矿物组成。实验结果表明,当潮土和红壤孔隙率均为45%时,甲苯在潮土中的迁移速率和最终迁移距离均显著高于在红壤中。甲苯在潮土中的阻滞系数(Rf=18.9)小于在红壤中(Rf=26.5),表明红壤对甲苯的吸附阻滞作用强于潮土。XRD表征结果显示,红壤中粒径小的黏粒含量较高,具有较多的黏土矿物,对甲苯具有更强的吸附阻滞能力,致使甲苯在红壤中垂向迁移速率小,最终迁移距离较短。 相似文献
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