基于FDS仿真火灾温度下隧道衬砌安全评估

为了研究火灾下隧道衬砌的安全性,首先采用火灾模拟软件FDS4．0模拟不同规模的火灾：通过许多小的长方体堆砌建立隧道的实体模型,并采用FDS4．0中的多重网格技术（Multiple Meshes）进行网格划分;然后结合仿真得到横断面的温度场与相应温度下的材料参数,应用荷载一结构模式（即直刚法）对二次衬砌的安全性进行评估。结果表明：小规模火灾下（〈20MW）,衬砌的安全性能够得到满足,在较大火灾规模下（≥20MW）,拱顶的安全性得不到满足,而其余部位的安全性满足要求;随着火灾规模的增大,衬砌安全系数逐渐降低,拱顶的安全系数降低梯度最大。最后,对衬砌的耐火措施提出了一些建议。     

西安市地面沉降成因机理中的若干问题探讨

针对西安市区的地质环境和地面沉降特征,总结国内外与此相关的研究成果,重点从土层渗流与变形特性、地面沉降和地裂缝的关系、下部地层压密与地面变形关系以及开采地热资源对地面沉降的影响等几个方面分析西安市区地面沉降研究的现状及存在的问题,并针对这些问题提出了几点建议.     

汶川地震灾区过渡房安置点场地选择中的地震问题

大地震后,如何在最短的时间内在灾区选择比较安全的过渡房安置点建设场地,是一项具有挑战性的工作。本文以四川省汶川8.0级大地震后灾区群众快速安置为背景,论述了选择过渡房安置点场地必须考虑的地震问题,并提出了处理地震断层、地表裂缝、砂土液化、坍塌等实际问题的方案;利用强余震的预测结果,分析了这些灾害对场地可能造成的危害;同时对可能潜在的滑坡、危岩崩塌、泥石流等地质灾害提出相应的处理建议,供安置点规划建设参考。     

拟合水工设计反应谱的人工地震波的生成与Huang变换校正

根据非平稳输入下建立的功率谱与均值反应谱之间的关系,合成基于水工设计反应谱的人工地震波,并对其幅值进行修正,降低了高频区误差作用;为了解决加速度时程积分后的速度、位移时程的零线漂移现象,利用Huang变换得到加速度时程的固有模态函数,由Huang变换方法得到的最低频率固有模态函数分量通常情况下代表原始信号的趋势或均值,对去掉均值后的加速度时程进行积分得到的速度、位移时程不存在零线漂移问题。     

Comparative on Causes and Accumulation of Selenium in the Tree-rings Ambient High-selenium Coal Combustion Area from Yutangba, Hubei, China

Toxic trace elements emitted during coal combustion are the main sources of air pollution. They are released into the atmosphere mainly in the forms of fine ash, smoke and flue, and thus adversely affect plant, animal and human health. Selenium is one of toxic and the most volatile in coal. Large amount of atmospheric emission of selenium, as well as selenium present and scrubber stockpiles in ash may create serious environmental problems. In the paper, on the basis of investigating the abundance and distribution of selenium in plant-rings during recent 20 years, the bioaccumulation of selenium is explained that selenium in plant, which were collected from the village of selenium-rich coal combustion, is much higher than that in plants collected away from the village of selenium-rich coal combustion. The main origins of selenium are selenium-rich coal combustion and high-selenium rock weathered. The selenium recycle by food chain and selenium will accumulate and redistribute in environments.     

RETRACTED ARTICLE: Environmental Impact Assessment of Industrial Structure Change in a Rural Region of China

As the embodiment of human activities, the change of regional industrial structure is an essential driving factor of global environmental change. Consequently, the research on the change of regional industrial structure and associated effects on the environment is one of the key issues of researches on sustainable development, human–environment relationship, and regional response to global environment change. However, compared to the flourish of researches on environmental impact assessment of industrial departments, few studies have been conducted to assess the environmental impact of regional industrial structure. In this study, based on a synthetic analysis of environmental disturbances of different industrial departments, the environmental impact coefficient of industrial department associated with the index of environmental impact of industrial structure was constructed, so as to make a quantitative assessment of environmental impact of the change of regional industrial structure. And the results of the case study in Lijiang City, a rural region of China, have showed that there are two obvious changes of industrial structure in the study area from 1992 to 2003, associated with a continuous decreasing of the index of environmental impact of industrial structure, which indicated a positive environmental effects of the change of regional industrial structure.     

资源和环境的存在价值的经济学基础

资源与环境的存在价值为独立与人们对资源的现期使用的价值。在资源,环境的代际问题中,存在价值会成为重要的决策参数。本文对存在价值的同予以分陈、归纳,并以反映其特点的结构进行表述;其次对存在价值与其它类别的价值尤其是期权价值,准期作出区分。     

Investigating an assessment model of system oil leakage considering failure dependence

Environmental Science and Pollution Research - Corrosion has made petrochemical infrastructure becomes a significant hazard of the surrounding environment. It is an excellent approach to reduce the...     

冷烧结法固化垃圾焚烧飞灰铅浸出特性

利用冷烧结法对垃圾焚烧飞灰(以下简称飞灰)进行了铅固化研究,分析了含水量、温度、压力和时间等参数对飞灰中铅固化效果的影响。结果表明:随着温度、压力和时间的增加,固化体的抗压强度大体升高且铅浸出浓度降低,当含水量为20%时,抗压强度达到最大。固化体的最小抗压强度为93.30MPa,最大抗压强度可达到233.23MPa。当温度为120℃、时间为100min、压力为50kN、含水量为15%时,固化体的铅浸出质量浓度为0.52mg/L,与飞灰相比降低了79.45%。     

Low ambient temperature increases hospital re-admissions for systemic lupus erythematosus in humid subtropical region: a time series study

Currently, the correlation between ambient temperature and systemic lupus erythematosus (SLE) hospital admissions remains not determined. The aim of this study was to explore the correlation between ambient temperature and SLE hospital admissions in Hefei City, China. An ecological study design was adopted. Daily data on SLE hospital admissions in Hefei City, from January 1, 2007, to December 31, 2017, were obtained from the two largest tertiary hospitals in Hefei, and the daily meteorological data at the same period were retrieved from China Meteorological Data Network. The generalized additive model (GAM) combined with distributed lag nonlinear model (DLNM) with Poisson link was applied to evaluate the influence of ambient temperature on SLE hospital admissions after controlling for potential confounding factors, including seasonality, relative humidity, day of week, and long-term trend. There were 1658 SLE hospital admissions from 2007 to 2017, including 370 first admissions and 1192 re-admissions (there were 96 admissions with admission status not stated). No correlation was observed between ambient temperature and SLE first admissions, but a correlation was found between low ambient temperature and SLE re-admissions (RR: 2.53, 95% CI: 1.11, 5.77) (3.5 °C vs 21 °C). The effect of ambient temperature on SLE re-admissions remained for 2 weeks but disappeared in 3 weeks. Exposure to low ambient temperature may increase hospital re-admissions for SLE, and thus it is important for SLE patients to maintain a warm living environment and avoid exposure to lower ambient temperature.