基于MCMC法的水质模型参数不确定性研究

参数识别是数学模型应用的前提.鉴于常用贝叶斯离散化方法在搜索复杂模型参数后验分布时的计算限制的原因,本文引入了MCMC采样法.为考察MCMC法对参数后验分布的搜索性能和效率,进行了2个案例研究.结果表明,MCMC法对参数后验分布的搜索,无论是搜索性能还是搜索效率,均表现出了独特的优越性.同时,Gelman收敛判别准则计算表明,MCMC采样序列均能稳定收敛到参数的后验分布上.可见,MCMC法适用于复杂环境模型的参数识别和不确定分析研究.     

试论环境保护新思维

掠夺型思维方式是造成当今环境危机的一个重要原因。随着环境危机的加剧，人类的思维方式必须进行革命性变革，而这种变革的关键是实现由掠夺型思维方式向可持续发展思维方式的转变。     

强化混凝去除微污染饮用原水中的As(III)

以聚合硫酸铁和聚合氯化铝为混凝剂,采用强化混凝的处理方法,对微污染饮用水原水中微量砷的去除进行了研究.考察了pH值、氧化剂用量、混凝剂投加量、砷初始浓度和原水浊度等因素对砷去除的影响.结果表明,聚合硫酸铁除砷效果好于聚合氯化铝;在pH值为6~8,微污染原水砷浓度为0.1mg/L,聚合硫酸铁投加量为0.078mmol/L时,可使滤后水中砷浓度低于0.01mg/L.     

Distribution and habitat characteristics of fishes in the Pearl River Estuary北大核心CSCD

To explore the current situation and distribution of fish in the eight major estuaries of the Pearl River Estuary in China, acoustic detection and water quality monitoring were conducted in 2018. The results showed that almost living in eight major estuaries were juvenile, the proportion of strong echo was higher in winter, and Jiaomen and Modaomen Estuary were relatively rich in adult fish. In winter, the Humen, Jiaomen, and Yamen Estuary had a high density relatively, for 46.05 (± 50.30), 33.12 (± 93), and 32 (± 78) ind/103 m3, respectively. However, the fish densities of the Hengmen, Modaomen, and Hutiaomen estuaries were higher in summer at 55.72 (± 83.23), 37.52 (± 55) and 36 (± 99) ind/103 m3, respectively. Thus, fish are mainly concentrated in the flood tidal estuary in winter and in the ebb tidal estuary in summer. In addition, fish density was higher in flood tide than in ebb tide, and the strong echo proportion was lower. In winter, the key water quality factors affecting the biodiversity of estuary fish Shannon were chlorophyll a (P < 0.05), while what affected the fish density were turbidity and salinity (P < 0.05). This study showed that the Pearl River estuary was still the main habitat for juvenile fish. However, habitat variability is obvious; hence, it is important to flexibly carry out the delimitation of estuarine fish reserves and ecological restoration. © 2022 Authors. All rights reserved.     

施工现场疫情防控风险评价方法

为准确科学地评估施工现场的疫情防控风险水平，通过文献查询、现场调研及专家咨询，构建了包含4个1级指标、17个2级指标的施工现场疫情防控风险体系，然后采用层次分析法(Analytic Hierarchy Process, AHP)与可靠度区间法(Reliability Interval Method, RIM)综合确定各级指标的权重，利用综合评价方法建立施工现场疫情防控风险评估模型，最后以某施工项目为例，验证该评价模型的有效性。结果表明，该项目现场整体风险指数为2.42,风险等级为中风险，其中防控体系风险等级为中风险，现场管理风险为较低风险，人员管理风险为较高风险，物资设备风险为中风险，与施工现场实际相吻合，该评估模型能较为准确、客观地反映施工现场疫情防控风险水平。     

抑制风力不确定扰动的缆机运行路径鲁棒优化

不确定性风力易导致缆机垂直运输过程中产生振荡效应，降低施工工效，甚至诱发安全事故。为抑制风力对缆机运行的不确定扰动，分析工期、机械使用效率和空间暴露风险等缆机运行路径优化目标及约束条件，运用鲁棒变换思想，将缆机运行路径规划问题抽象为多目标鲁棒优化模型，并采用交叉熵进化算法求解具有鲁棒性的帕累托前沿及缆机运行路径。案例结果表明，随鲁棒保守度增大，风力等随机性因素的影响不断增强，需要增加工期和降低机械使用效率，使空间暴露风险降低，表明所获得的帕累托前沿能够减小风力等不确定性干扰并满足工期、效率和风险等多目标需求。