基于粒子群优化的DGM（1,1）模型在基坑变形安全预测中的研究

为确保基坑施工期间发生变形后能够正常使用,将变权缓冲算子结合DGM(1,1)模型构造出变权离散灰色模型,利用相对误差、后验差比,灰色绝对关联度3种精度检验法作为粒子群算法适应度建立模型,构造PSO-VWDGM(1,1)模型,并结合实际工程监测数据研究不同适应度对基坑变形预测精度的影响。研究结果表明:不同适应度函数对预测精度存在较大影响,以灰色绝对关联度作为适应度建立模型预测精度较高,可以更好应用在工程中。研究成果可为工程施工阶段的基坑变形预测、稳定性分析与灾害评估、预警提供参考。     

基于贝叶斯网络的建筑火灾动态风险评估方法研究

为提高建筑火灾风险评估的准确性,建立1种智能化的动态风险评估方法。针对具体建筑的风险评估,以物联网技术为基础,构建智能消防监测系统,在建筑日常使用过程中通过动态风险评估,实现火灾风险要素的实时监测、数据传输,充分发挥大数据、云计算的支撑作用,将贝叶斯网络方法引入火灾风险定量评估过程,构建火灾动态风险评估模型;结合具体的应用实例,分析不确定因素对风险评估结果的影响。研究结果表明:基于贝叶斯网络的动态风险评估方法能较准确地反映建筑火灾风险的可能性,达到实时监测、动态评估的效果。     

Effect of ignition position on vented hydrogen–air deflagration in a 1 m3 vessel

This study investigates the effect of the ignition position on vented hydrogen-air deflagration in a 1 m³ vessel and evaluates the performance of the commercial computational fluid dynamics (CFD) code FLACS in simulating the vented explosion of hydrogen-air mixtures. First, the differences in the measured pressure-time histories for various ignition locations are presented, and the mechanisms responsible for the generation of different pressure peaks are explained, along with the flame behavior. Secondly, the CFD software FLACS is assessed against the experimental data. The characteristic phenomena of vented explosion are observed for hydrogen-air mixtures ignited at different ignition positions, such as Helmholtz oscillation for front ignition, the interaction between external explosion and combustion inside the vessel for central ignition, and the wall effect for back-wall ignition. Flame-acoustic interaction are observed in all cases, particularly in those of front ignition and very lean hydrogen-air mixtures. The predicted flame behavior agree well with the experimental data in general while the simulated maximum overpressures are larger than the experimental values by a factor of 1.5–2, which is conservative then would lead to a safe design of explosion panels for instance. Not only the flame development during the deflagration was well-simulated for the different ignition locations, but also the correspondence between the pressure transients and flame behavior was also accurately calculated. The comparison of the predicted results with the experimental data shows the performance of FLACS to model vented mixtures of hydrogen with air ignited in a lab scale vessel. However, the experimental scale is often smaller than that used in practical scenarios, such as hydrogen refueling installations. Thus, future large-scale experiments are necessary to assess the performance of FLACS in practical use.     

淋雨及不同温度条件对消防员防护服各部位热阻的影响

为了研究淋雨及不同温度条件对消防员防护服各部位热阻的影响，以消防防护服为研究对象，利用环境舱和暖体假人系统，在20 mm/h降雨强度和20~30 ℃的复合环境条件下，研究淋雨、不同温度复合环境对服装各部位热阻的影响。研究结果表明:淋雨过程中，服装热阻的变化趋势为先上升再下降最后趋于稳定；淋雨与不同温度复合环境会使得消防防护服热阻降低，其中影响较大的部位为上臂部、腹部、胸部、背部及臀部等。     

旅游资源竞争力与旅游收入关系实证分析——以安徽省17地市为例

在构建旅游资源竞争力评价指标体系的基础上，运用位序得分法对安徽省17个地市的旅游资源竞争力进行了评价，同时借助两轴折线图、散点图及拟合曲线等工具对17个地市旅游资源竞争力与旅游收入关系进行了实证分析。结果表明，安徽省绝大多数地市旅游业发展仍依赖于旅游资源；少数地市旅游资源竞争力与旅游收入出现偏离，成为非旅游资源依赖性城市。从资源属性来看，综合类旅游资源与旅游收入的相关性最大，其次为自然类旅游资源，人文类的相关性最小。     

Determinant factors of corporate environmental information disclosure: an empirical study of Chinese listed companies

In order to help understand the environmental disclosure mechanism from the corporate perspective, this paper identifies the determinant factors affecting the disclosure level of corporate environmental information on the basis of stakeholder theory, and gives an empirical observation on Chinese listed companies. The corporate environmental information disclosure (EID) level appears to be marginal in current Chinese context. Nearly 40% of the sampled companies opened no substantial environmental data to the public as could be seen from the content analysis of disclosed information. The present condition is that the EID strategy of Chinese listed companies is oriented to fill up the government's environmental concerns. The corporate EID effort is significantly relative to its environmental sensitivity (a proxy of the pressure from the government) and its size. The role of other stakeholders, like shareholders and creditors tested in this study in effecting the EID, is found to be still weak. Another interesting finding is that the sampled companies are selectively opening their environmental information. Companies operating in eastern coastal regions, where the economy has been relatively developed, are more likely to disclose emission-related data. The better the company's economic performance, the more information on environmental investment and pollution control cost is disclosed. More concerns of the firm's stakeholders on environmental issues shall be promoted in order to encourage Chinese enterprises to disclose more environmental information and accordingly become more proactive for improving their environmental performance.     

Environmental geochemical characteristics of rare-earth elements in surface waters in the Huainan coal mining area,Anhui Province,China

Environmental Geochemistry and Health - This study investigated the environmental geochemical characteristics of rare-earth elements (REEs) in surface waters in the Huainan mining area, Anhui...     

中国二氧化硫污染的“稳健性”影响因素——基于空间面板数据EBA模型的实证分析

改革开放以来,中国的经济发展取得了举世瞩目的成就.然而,随着经济的快速增长,环境污染问题也日益凸显.本文采用2000—2012年中国30个省际的面板数据,利用环境库兹涅茨曲线(EKC)理论检验二氧化硫(SO2)污染与经济增长的关系及其空间溢出效应,进而引入极值边界模型(EBA模型)实证检验SO2污染的"稳健性"影响因素.结果表明:我国各省域SO2污染与经济增长存在EKC曲线假设的倒"U"型关系,并具有空间溢出效应;第二产业就业人口比重、出口占GDP的比重、能源效率、化石能源比重、工业污染治理完成投资与SO2排放量呈正向"稳健性"关系,产业结构升级与SO2排放量呈负向"稳健性"关系.最后根据实证结论提出相应的政策建议,为政府制定相应的SO2减排政策提供经验证据和决策参考.     

还原共沉淀法制备Fe-Ti复合氧化物及其吸附水中As(Ⅴ)的研究

采用还原-共沉淀法制备了无定型纳米复合Fe-Ti氧化物(FFT)吸附剂,并研究其对水中低浓度As(Ⅴ)的去除性能.XRD表征结果表明,制备的纳米FFT物相为无定型,BET比表面积达325.3 m2·g-1,计算得到的BJH吸附平均孔径为2.46 nm(4V/A),颗粒分布均匀.同时,考察了纳米FFT吸附As(Ⅴ)的动力学、热力学、吸附等温线,以及温度、水中共存离子对其去除As(Ⅴ)的影响.结果发现,纳米FFT对As(Ⅴ)的吸附符合拟二级动力学模型,计算出的孔道扩散系数DP在10-11~10-13cm2·s-1之间,显示孔扩散是速率限速步骤.Langmuir、Freundlich和DubininRadushkevich(D-R)吸附等温式均可较好地拟合吸附行为,低浓度下Langmuir吸附模型计算出的Qm达到26.46 mg·g-1.最后,研究了地下水中常见的共存离子对吸附的影响,发现Ca2+、Mg2+能够促进吸附,H2PO-4和HCO-3则明显抑制吸附过程.     

2,3,7,8-四氯代二苯并噻吩在锦鲫不同组织中的生物富集及对肝脏的氧化损伤

研究了含硫"类二噁英"化合物多氯代二苯并噻吩(PCDTs)中的2,3,7,8-四氯代二苯并噻吩(2,3,7,8-TCDT)在锦鲫(Carassius auratus)不同组织中的生物富集规律和对肝脏的氧化损伤.结果表明,2,3,7,8-TCDT在锦鲫各组织中的富集能力表现为肝脏>鳃>肌肉.2,3,7,8-TCDT在锦鲫...