纵向通风对隧道竖井排烟影响的模拟研究

通过开展小尺寸实验以及FDS数值模拟实验,研究纵向通风对不同高度竖井的排烟影响并确定最佳通风风速。通过分析纵向通风风速、竖井高度对吸穿现象、边界层分离的影响规律,讨论了吸穿现象的临界条件。小尺寸实验中纵向通风风速考虑了0.096 m/s、0.226 m/s、0.356 m/s、0.485 m/s、0.629 m/s五种工况,竖井高度考虑了0.133 m、0.2 m、0.333 m、0.533 m四种工况。实验结果表明:当纵向通风风速为0.096 m/s、0.226 m/s、0.356 m/s(对应实际风速0.37 m/s、0.87 m/s、1.38 m/s)时,可抑制吸穿现象,但烟气边界层分离现象随着风速的增加而加剧。吸穿现象临界判据F_(critical)=1.5在本文所测试的纵向通风条件下不再适用,但Ri′_(critical)=1.5依然适用。数值模拟结果表明:当竖井高度为1 m、1.5 m、2 m时,排烟量随纵向通风的增加而降低,而当其为3 m、4 m、5 m时,排烟量先上升后降低,在测试风速为1.5 m/s时达到最高值。     

基于Landsat 8遥感数据的天津市地表温度反演

以Landsat 8遥感数据为数据源,进行天津市地表温度反演研究。首先采用单通道算法反演地表温度,并利用均值标准差法进行温度分级。然后建立不同温度等级面积比例的估算模型。再通过随机样点,从不同温度等级和土地覆盖类型2个角度,分别建立并比较不同类样点的地表温度与各指数的拟合模型。结果表明:次高温区域面积比例与人口密度、人均GDP都具有较高的决定系数;地表温度与NDVI、BAEM的二元线性回归决定系数高于地表温度与单一指数的决定系数;将样点分类后,低温点与MNDBI的决定系数高于其他温度等级样点,水域和植被样点与各种指数的决定系数高于其他地物类型样点。     

"十三五"国家自然科学基金对能源环境管理领域的资助状况和趋势

能源环境管理是各界关注的热点话题,也是科学研究的重要方向.以国家自然科学基金资助能源环境管理领域的科研项目为基础数据信息,本文重点分析了"十三五"期间国家自然科学基金在该领域资助项目的总体特征、研究主题和热点变化,并结合新时代科学基金资助导向提出了可能的发展趋势.主要结论包括:①能源环境管理领域面上、青年、地区等自由探索类项目的立项绝对数和学科占比均呈上升趋势,并更多向青年学者倾斜,资助强度保持稳定;②碳、能源和环境是自由探索项目中出现频率最高的热词,与之相关的研究主题随着政策等调整具有动态变化特征;③能源环境管理领域重点、重大等引导类项目和优青、杰青、创新研究群体等人才类项目不断实现突破,增速明显,学科占比优势突出;④问题导向与本土情景、理论体系和一般规律、学科交叉融合,以及市场和微观主体作用是研究选题确立与项目申请时可能需要重点关注的方向.     

珠江口表层水中多环芳烃的分布特征及健康风险评估

分别于2015年2、5、8、11月在珠江八大入海口采集表层水体样品,应用固相萃取富集法对该区域表层水体中16种USEPA优控多环芳烃(PAHs)的时空分布特征进行分析,并利用终生致癌风险增量模型(ILCR)对该区域的饮水健康风险进行评价。结果表明:珠江口4个季度所采集的水样中,∑15PAHs的浓度范围为18.0~50.3 ng/L,含量处于中等水平。其中7种强致癌性∑7PAHs的浓度范围为1.53~3.73 ng/L,占∑15PAHs的5.89%~11.1%,∑15PAHs和∑7PAHs在枯水期(2、11月)样品中明显高于丰水期(5、8月)。就组成特征而言,各采样点PAHs以3、4环为主。珠江口表层水中非致癌类PAHs的危害商数值为0.99×10~(-5)~2.73×10~(-5),远低于USEPA规定的阈值(1);致癌类PAHs产生的健康风险为6.50×10~(-8)~2.37×10~(-7),其中Ba P导致的饮水途径健康风险最高,所有点位致癌类PAHs的健康风险均低于USEPA推荐的对致癌物质最大可接受风险水平(10~(-6)),表明珠江口表层水中PAHs尚不具备严重的致癌风险,但是仍然存在潜在的健康风险,需要重点控制和管理。     

北京市发展CNG汽车的条件与前景分析

北京市汽车排放污染物贡献率已达到：HC73.5％，CO63．4％，NOx46％。用CNG代替汽油作汽车燃料，可使CO减少97％、HC减少72％、NOx减少39％、CO2减少24％、SO2减少90％。建立CNG加气站和CNG汽车改装这两个CNG应用关键问题在技术上、经济上都是可行的。北京市CNG燃料来源有保障。北京市车辆都比较适合使用CNG气体燃料。北京有很强的CNG汽车产业科技力量。对北京市当前发展CNG汽车产业提出了一些建议。     

Making Capacity Building Meaningful: A Framework for Strategic Action

This paper aims to give practical meaning to ‘capacity building’ through (a) identifying a suite of practical measures, such as mentoring or best practice guidelines, that have been shown to or are considered to build human, social, institutional, and economic capital; (b) placing these measures within a broader systems framework; and (c) exploring stakeholder feedback on specific measures to inform framework implementation. The 29 measures described provide actors, whether government or nongovernment, with a suite of practical investment choices for building capacity. These measures are then clustered into eight groups according to their primary purpose and placed within a systems framework. The framework provides a tool for actors with responsibilities for or an interest in capacity building to inform more holistic and strategic targeting of effort and investment. Stakeholder feedback gathered through surveys and workshops is subsequently reported to further inform implementation of specific measures within the framework’s eight groupings. The framework presented may be built upon through the identification and inclusion of further capacity building measures. The research is conducted within the context of decentralized governance arrangements for natural resource management (NRM), with specific focus on Australia’s recently formalized 56 NRM regions and their community-based governing boards as an informative arena of learning. Application of the framework is explored in the Australian setting through the identification and comparison of measures supported and most preferred by four major stakeholder groups, namely board members, regional NRM organization staff, policy/research interests, and Indigenous interests. The research also examines stakeholder perceptions of capacity issues, and whether these issues are likely to be addressed through implementing their preferred measures.

人工神经网络在预测深基坑周边地表沉降变形中的应用研究

深基坑开挖引起的周边地表变形预测是一个复杂非线性问题,引起地表沉降的影响因素很多,各因素之间呈高度的非线性关系。传统的基坑用边地表沉降变形预测方法存在着一定的局限性,其预测精度有待提高,而人工神经网络是一种多元非线性动力学系统,可以灵活方便地对多成因的复杂未知系统进行高度建模,实现全面考虑各种主要影响因素的深基坑周边地表沉降变形预测。本文介绍了误差反向传播(BP)网络模型的结构、学习过程及其算法的改进,径向基函数(RBF)网络模型的结构及其学习过程;分析了影响深基坑开挖周边土体沉降变形的主要影响因素;以25个基坑工程的地表沉降实测资料为训练样本,建立了11个输入影响因素的BP神经网络模型和RBF神经网络模型,通过对样本的学习训练过程及对5个检验样本的预测精度,说明了人工神经网络用于预测基坑周边地表沉降的可行性和准确性。     

区域性“减灾十年初步规划”的编制原则

本文简要介绍区域性“减灾十年初步规划”编制的一般原则，包括规划编制的意义、目的、编制顺序和规划应注意的几个方面，并提出规划成果的实施意见。可供各地编制规划时参考。     

Co-ordination for disasters

This paper was prepared in 1978 on the basis of a review of sociological and anthropological fieldwork conducted up to that time. Although theoretical in presentation its conclusions are formulated in accordance with the author's own extensive observations of organizational response to natural disasters in developing countries, especially those having sudden onset. Practical implications for co-ordination agencies and pre-disaster training are drawn.     

Climate hazards: Lessons from recent events in the United States

Three recent cases of climate extremes are studied to identify human impacts and response strategies and to identify common characteristics that may help illuminate the nature of climate hazards. The 1980 heat wave in the central United States, 1981 cold wave in Boston, Massachusetts, and recent flooding and lake level rise in northern Utah, illustrate several important aspects of climate hazards that separate them from the more traditional set of catastrophic events (e.g. tornadoes, hurricanes and earthquakes) usually dealt with by hazards research and management. Among those characteristics are an emphasis on health impacts rather than physical damage, accumulative effects rather than short shocks, a tendency for impacts to accrue to certain socio-economic classes, and relatively slow onset. The management and research implications of these hazard characteristics are explored.