大气多源排放全方位C_(max)预测方法及编程技巧

大气环境评价中预测最大落地浓度是为了确定拟建工程污染物排放的最大影响水平。常用的最大落地浓度预测模式仅适用于单个点污染源 ,本文对多个点、面源排放提出了用高斯正态模式直接预测全方位地面最大浓度的实用方法。该方法在编程计算时如采用距离步长双重循环方式 ,可快速逼近最大浓度出现距离 ,以提高计算速度 ,同时保证预测精度 ;通过单点源实例 ,在模式和编程技巧上验证了这一方法的可靠性和精确性。     

基于TOP-RICE模型嘧菌酯·噻呋酰胺4%展膜油剂稻田水溢出对水生生态系统风险评估研究

为评估嘧菌酯·噻呋酰胺4%展膜油剂在我国稻田水溢出对水生生态系统的风险,本研究依据中华人民共和国农业行业标准NY/T 2882.2—2016《农药登记环境风险评估指南第2部分:水生生态系统》,采用TOP-RICE暴露模型分别单独评估了嘧菌酯和噻呋酰胺2种有效成分稻田滴撒方式应用时水溢出对水生生态系统的风险。其中,TOP-RICE初级暴露模型中有我国连平和南昌2个水稻-地下水暴露场景,每个场景都对分蘖期和拔节期进行分别评估。分析结果显示,嘧菌酯·噻呋酰胺4%展膜油剂中的嘧菌酯按照申请的良好农业规范(GAP)使用,生物富集风险可接受,初级风险评估对无脊椎动物(急性)和无脊椎动物(慢性)风险不可接受,但经中宇宙研究后,在连平和南昌2个场景点,均为拔节期用药对无脊椎动物的风险可接受,但分蘖期用药对无脊椎动物的风险不可接受;嘧菌酯·噻呋酰胺4%展膜油剂中的噻呋酰胺按照申请的GAP使用,生物富集带来的风险可以接受,经初级风险评估风险均可接受。在忽略2种有效成分相互间作用时,初步认为嘧菌酯·噻呋酰胺4%展膜油剂在我国稻田拔节期按照GAP要求施用时水溢出对水生生态系统的风险可接受,但应避免在分蘖期用药,以免其中的有效成分嘧菌酯对水生无脊椎动物产生不良影响。     

A framework for evaluation of flood management strategies

The resulting impact of disasters on society depends on the affected country's economic strength prior to the disaster. The larger the disaster and the smaller the economy, the more significant is the impact. This is clearest seen in developing countries, where weak economies become even weaker afterwards. Deliberate strategies for the sharing of losses from hazardous events may aid a country or a community in efficiently using scarce prevention and mitigation resources, thus being better prepared for the effects of a disaster. Nevertheless, many governments lack an adequate institutional system for applying cost effective and reliable technologies for disaster prevention, early warnings, and mitigation. Modelling by event analyses and strategy models is one way of planning ahead, but these models have so far not been linked together. An approach to this problem was taken during a large study in Hungary, the Tisza case study, where a number of policy strategies for spreading of flood loss were formulated. In these strategies, a set of parameters of particular interest were extracted from interviews with stakeholders in the region. However, the study was focused on emerging economies, and, in particular, on insurance strategies. The scope is now extended to become a functional framework also for developing countries. In general, they have a higher degree of vulnerability. The paper takes northern Vietnam as an example of a developing region. We identify important parameters and discuss their importance for flood strategy formulations. Based on the policy strategies in the Tisza case, we extract data from the strategies and propose a framework for loss spread in developing and emerging economies. The parameter set can straightforwardly be included in a simulation and decision model for policy formulation and evaluation, taking multiple stakeholders into account.     

Effect of adjuvants on rainfastness and herbicidal activity of glyphosate deposits on trembling aspen foliage

Abstract

Radiolabelled end‐use mixtures of glyphosate with and without a cationic surfactant (Ethomeen® T/25) and an organosilicone surfactant (Silwet® L‐77) were applied onto trembling aspen (Populus tremuloids Michx.) leaves at the rate of 1.0 kg of AE (acid equivalent) in 35 L/ha area of foliage. A 5‐mm rainfall with an intensity of 10 mm/h was applied at intervals of 0.5, 8, 24, 36, 48, 72, and 96 h after treatment. Glyphosate washoff was determined by liquid scintillation counting of radioactivity in the rain‐washing. At 36 h post‐treatment, both the adjuvants significantly reduced glyphosate washoff (Ethomeen by 69.6% and Silwet by 59.7%) from foliage, compared to the washoff (82.6%) when Vision alone was applied without the adjuvants. Results on the rate of plant growth indicated that with a rain‐free period of 8 h or more, the growth of most seedlings was stunted within 1 or 2 d. Percentage of foliar browning 20 d after treatment with rain‐free period of 8 to 48 h ranged from 8 to 80% for Vision alone, 75 to 100% for Vision with Ethomeen, and 85 to 100% for Vision with Silwet, respectively. Physical properties of the end‐use mixtures were measured with and without the two adjuvants to examine droplet spreading and drying rates in relation glyphosate rainfastness. The Silwet adjuvant lowered the surface tension of the end‐use mixture, but Ethomeen did not. Droplets containing Silwet were spread more than those containing Ethomeen. However, the greater area of contact caused by Silwet did not contribute to a significant increase in the translocation rate of glyphosate into untreated parts of the seedlings, and showed no relationship with rainfastness of glyphosate deposits on trembling aspen.     

基于GIS的地震次生火灾蔓延范围模拟

地震次生火灾对人类的危害极大。笔者首先在对阻止火蔓延的因素进行分析以及对以往调查资料分析的基础上,确定了阻止火蔓延的距离与建筑物结构及防火类型的关系。然后,在阻止火蔓延距离的基础上,确定了地震次生火灾蔓延范围模拟的方法以及流程。最后,以汕头市为例,对地震次生火灾蔓延范围进行了模拟。通过对地震次生火灾蔓延范围的研究,为地震应急救灾提供了决策的科学依据。     

窄带水平集法下林火蔓延仿真研究

火焰锋面的追踪是建立林火蔓延模型及预测锋面位置的关键环节。基于水平集法追踪锋面具有求解灵活稳定、易于处理锋面拓扑结构变化的特点。针对传统水平集法重新初始化过程复杂、计算量较大的问题,根据距离函数定义,提出通过形态学膨胀的方法以锋面点为圆心向外膨胀,获得锋面附近窄带内每个点距离锋面的最近距离,重建窄带内的水平集函数,物理意义明确,有效减小了计算量,在此基础上基于林火速度场经验模型模拟了单火源及双火源的锋面蔓延情况。结果表明,该方法能够有效模拟坡度、风速等因素对火焰锋面的影响,为其在林火蔓延模型中的应用提供了基础。     

地震液化引起地面侧向大变形研究评述

本文对地震液化引起的地面侧向大变形国内外研究现状从试验研究与分析计算方法两方面进行评述,探讨了液化侧向变形需要进一步研究的一些问题。     

大型商业建筑中的性能化设计问题探讨

本文分析了大型商业建筑的建筑特点、火灾特点及火灾危害性,并基于性能化防火设计的理念,针对某大型商场的建筑特点和性能化问题,提出了通过设置防烟走廊阻止火灾高温烟气进入作为疏散临时安全区的中庭的设计方法。在合理估算建筑内火灾和人员荷载的基础上,选用合适的模型,通过对火灾情况下的烟气蔓延和人员疏散进行数值模拟和分析,验证了防烟走廊的设置可有效提高中庭的防火安全性能。     

畜禽废水处理技术及其应用进展

针对我国养殖业废水污染日益严重的现状,介绍了畜禽废水还田利用、自然处理以及工业化处理的优缺点、国内外应用现状以及研究的重点,并结合我国的实际情况,提出现阶段我国养殖业废水应重点发展还田利用技术与自然处理技术,并及时建立畜禽废水处理设计数据库以及编写设计规范。     

利用数字地震波资料研究新疆天山中东段地区的介质衰减特征

利用新疆数字地震台网记录的155条地震波形资料,根据S波记录得到观测振幅谱,采用遗传算法联合反演的方法研究了新疆天山中东段地区(乌鲁木齐—乌苏—库尔勒地区)的几何衰减模型、介质非弹性衰减模型。结果表明:在500 km震源距范围内,研究区地震波的几何衰减满足三段衰减模型;研究区非弹性衰减Q值随频率f的关系为:Q(f)=344f~(0.55)。本研究为今后在该研究区利用数字地震观测资料开展震源谱的恢复和强地面运动的模拟等地震学、工程地震学研究奠定了基础。