Effects of Acid Rain on Competitive Releases of Cd, Cu, and Zn from Two Natural Soils and Two Contaminated Soils in Hunan, China

Leaching experiments of rebuilt soil columns with two simulated acid rain solutions (pH 4.6–3.8) were conducted for two natural soils and two artificial contaminated soils from Hunan, south-central China, to study effects of acid rain on competitive releases of soil Cd, Cu, and Zn. Distilled water was used in comparison. The results showed that the total releases were Zn>Cu>Cd for the natural soils and Cd>Zn≫Cu for the contaminated soils, which reflected sensitivity of these metals to acid rain. Leached with different acid rain, about 26–76% of external Cd and 11–68% external Zn were released, but more than 99% of external Cu was adsorbed by the soils, and therefore Cu had a different sorption and desorption pattern from Cd and Zn. Metal releases were obviously correlated with releases of TOC in the leachates, which could be described as an exponential equation. Compared with the natural soils, acid rain not only led to changes in total metal contents, but also in metal fraction distributions in the contaminated soils. More acidified soils had a lower sorption capacity to metals, mostly related to soil properties such as pH, organic matter, soil particles, adsorbed SO₄ ²⁻, exchangeable Al³⁺ and H⁺, and contents of Fe₂O₃ and Al₂O₃.     

旅游安全风险系统研究

在现代旅游活动中,旅游安全问题日益突出。其活动涉及大、中、小尺度的地域范围,牵涉行业较多,旅游安全存在于旅游行业及其活动的各个环节。当前的旅游安全问题不仅仅是个技术问题,而已成为一个很严重的社会问题。笔者从系统论和旅游地理学的角度,把旅游安全作为一个风险系统进行研究;认为旅游安全风险系统是由旅游者与旅游景区环境共同组成的一个复杂的特定的相互依赖的系统;初步探讨旅游安全风险系统的组成、结构和研究内容;对旅游安全风险系统的安全分析、安全评价和安全措施进行了相关研究;通过研究,以期弄清现代旅游业发展中存在的安全问题,提出旅游安全风险对策。     

电絮凝净化含聚污水影响因素研究

目的为保障油田正常安全生产,促进油田含聚污水的循环利用。方法采用电絮凝技术单因素研究方法开展净化含聚污水的静态实验研究,探讨外加电流密度、极板间距、初始pH及聚合物浓度等因素对净化效果的影响规律。结果当初始pH为7.0,电流密度为4.0 m A/m2,极板间距为1.0 cm,电解16 min时,综合处理效果最佳。此时,含油量与浊度去除率分别为98.85%,99.93%,处理每克油平均消耗为0.0494 g的Al,处理每立方米含聚污水的能耗为0.2895 k Wh。污水中的聚合物浓度越小,净化效果越好。结论中性处理,极板间距为1.0 cm,外加电流密度为4.0 m A/m2,通电16 min是最佳处理条件。     

地铁多线换乘车站火灾模型实验研究—(1)模型装置设计

为研究地铁网络化运营枢纽车站火灾烟气扩散特征和防排烟技术,根据工程资料和标准规范对典型多线换乘车站进行1∶10火灾实验模型设计,并依据设计方案完成车站模型主体结构和通风排烟系统的搭建,同时在各个防烟分区设计安装温度、流速、烟气浓度和热辐射测量装置,可实现对“T”形、“十”形和“L”形换乘等不同换乘形式车站的火灾场景模拟和危险参数测量。研究结果表明:该模型装置能够开展一系列针对不同换乘形式和通风模式的火灾实验,对于全面揭示大型换乘车站火灾烟气运动规律、验证并优化火灾防排烟设计方法、支撑复杂结构枢纽车站火灾烟气控制技术具有重要意义。     

基于生态槽实验的藻类生长参数确定

在太湖湖泊生态系统研究站的生态模拟槽中进行了藻类的动态模拟实验.取太湖原水至生态槽中,在温度、光照、营养盐变化条件下进行采样,观察藻类的变化情况.在生态槽实验基础上应用PHREEQC模型建立了藻类生长模型,模型中考虑了氮及磷营养盐的循环过程.利用生态模拟槽实验结果对太湖藻类生长模型的各参数进行了详细的率定验证,并应用最小二乘法确定最佳的一组参数,藻类及各种营养盐浓度的模拟值均能较好地拟合实验测量值.     

双风机并联机站局阻特性研究

为探究双风机并联机站局部阻力特性、完善机站局部阻力及其系数的计算公式,以实际矿井通风机站为工程背景,在分析机站流场能量损失机理的基础上,采用物理模型实验和数值计算相结合的方法,分析了机站入口分流、出口汇流的断面速度不均匀程度与机站阻力损失的关系,同时对不同宽高比的矩形断面进行多工况模拟。结果表明:断面速度不均匀性越大,速度分布重组造成的阻力损失越大;确定了机站局阻计算所需参数的合理测定位置,得出机站局阻系数计算时的综合影响系数Kc随风机工况增大而增大、随断面宽高比A增大而减小,并呈现较好的线性关系。研究结果可为多级机站通风系统通风阻力特性分析以及工程优化设计提供参考。     

加卸荷条件下岩石力学特性与声发射特征

为了探究真三轴复杂应力变化条件下岩石强度及破坏模式,通过真三轴卸荷扰动测试系统对砂岩试件进行不同第二主应力加卸荷试验,讨论在加卸荷过程中岩石的力学特性及声发射特征。试验结果表明:第二主应力的增加对试件的承载能力起到先增强后弱化的效果;不同第二主应力加卸荷声发射能量及累计振铃计数变化趋势大体一致,耗散能量比在载荷达到岩石损伤强度时突增;声发射能量峰值提前于试件轴向应力跌落,声发射能量和累计振铃计数大幅突增可作为岩石破坏的前兆;在低载荷下岩石中活动主要是裂隙压密与发育,在达到岩石损伤强度后岩石中的活动主要是裂纹贯通形成破裂面,砂岩试件声发射定位点集中区域与试件主要破裂面基本吻合。     

k-C*模型的人工湿地模拟研究

采用自由表面流人工湿地,对广东省中山市某小区对应段的河涌进行生态修复改造。基于k-C*模型的计算结果表明,在对现有河涌的面积的利用下,TP和NH4+-N的去除效果受到限制。采用多因素正交实验对模型的计算结果进行实验验证和分析,研究了4种植物、4种基质,分别在2、4、6和8 d水力停留时间(HRT)下对TP和NH4+-N的去除效果,得到影响TP和NH4+-N去除效果的因素主次顺序分别为基质→植物→HRT和基质→HRT→植物;各因素的最佳水平条件分别为:风车草、颗粒活性炭、4 d(HRT)。在最佳水平条件下进行实验,结果表明,TP和NH4+-N的浓度均可达到出水排放标准浓度指标。k-C*模型的计算值总是比实验值偏高,但两者之间的误差在一个数量级范围内。     

Ecotoxicological effects of mixed pollutants resulted from e-wastes recycling and bioaccumulation of polybrominated diphenyl ethers in Chinese loach (Misgurnus anguillicaudatus)

To understand potential ecotoxicological effects of electrical and electronic equipment waste (e-waste) recycling and polybrominated diphenyl ethers (PBDEs) bioaccumulation in loaches, a semi-field experiment using Chinese loach (Misgurnus anguillicaudatus) as experimental fish was performed. Larval loaches were kept into net-cage for three months in an e-wastes recycling site and a reference site in Southeastern China. There was significant difference of the survival rate between the loaches from the e-wastes recycling site (27%, 19/70) and from reference site (70%, 49/70). Histopathological responses were also found in all the livers examined in loaches from the e-wastes recycling site. These results showed that mixed pollutants resulted from e-wastes recycling led to ecotoxicological effects on loaches. The bioaccumulation of polybrominated diphenyl ethers (PBDEs), the main pollutants in e-waste, in loaches was also studied in this e-wastes recycling site, the mean concentrations of total PBDEs in sediment was 6726.17 ng/g wet weight and in water samples was 4.08 ng/L (dissolved phase). BDE209 was the dominant congener in sediment and with relatively high concentration in water. Relatively low concentration of BDE209 (less than 0.01% of total PBDEs) and high concentration of BDE47 (up to 39.34% of total PBDEs) were detected in loaches.     

沉床微生态控制体对水体TP及COD的去除率研究

针对水体富营养化的生态逆境,以个体沉床微生态作为研究的基本单元。即通过控制其非生物和生物成分,局部构建以满足水生植物适生环境为核心的水体生态结构体,由个体到总体,以点带面,从而实现总体生态功能目标的恢复。此法融合了恢复生态学人为设计、自我设计理论,并突出人为干预的主导作用。通过沉床微生态控制体改善水质的正交试验,运用数量化理论分析方法,筛选出最佳组合为陶粒箱+页岩+金钱蒲+雨久花,在静态时TP的去除率可达到(76.6±1.17)%,COD的去除率达到(37.4±2.27)%;在动态时TP的去除率可达到(39.5±1.17)%,COD的去除率达到(16.03±1.41)%。其显著性与可靠性均达到95%以上,此结果可作为两种水体恢复应用时的参考。