岩溶区地下水补给型水库表层无机碳时空变化特征及影响因素

为更深入地认识岩溶区地下水补给型水库表层无机碳的循环过程,于2014-07-12~2014-07-20期间,以广西上林县大龙洞岩溶水库表层水体为研究体系,对无机碳循环研究的重要指标进行定点观测和高密度的昼夜监测.结果发现:1从上游到下游DIC含量和水体p CO2值逐渐增加[DIC(平均):122.88 mg·L-1增至172.02 mg·L-1,p CO2(平均):637.91×10-6增至1 399.97×10-6],δ13CDIC值逐渐偏负[δ13CDIC(平均):-4.34‰降至-6.97‰].2库区均为大气CO2的源,CO2交换通量在7.11~335.54 mg·(m2·h)-1之间,平均125.03 mg·(m2·h)-1,上游和下游地区CO2交换通量较大[平均131.73 mg·(m2·h)-1、170.25 mg·(m2·h)-1],中游狭窄地区CO2交换通量较小[平均116.05 mg·(m2·h)-1].3表层水体p CO2值和水-气界面CO2交换通量存在晚上升高,白天降低的昼夜变化规律,且与叶绿素a(Chla)呈负相关关系.分析认为:1大龙洞水库表层水体DIC含量、δ13CDIC值和水体p CO2的空间分布主要受浮游植物浓度、浊度、电导率、水深、透明度等的影响,而水-气界面CO2交换通量除了受浮游植物浓度空间变化的影响外还受风速的影响.2浮游植物昼夜垂向运动及光合作用和呼吸作用昼夜变化控制着水库表层水体溶解性无机碳的昼夜循环过程.     

污水生化过程后置化学辅助除磷的实验研究

在城市污水生物处理过程中,投加化学药剂有助于出水的磷达标,但化学辅助除磷的效果受多种因素影响。针对投加位置、污泥浓度、温度、p H值、DO对后置化学辅助除磷效果的影响开展实验研究,有助于后置化学辅助除磷过程的优化控制。结果表明:在二沉池前投加混凝剂的方式TP去除率较高;在温度、p H值、DO一定条件下,TP去除率与投加量均呈现显著线性正相关,和污泥浓度无关;温度对TP去除率有影响,温度低于18℃时TP去除率较高;p H值对TP去除率有影响,p H为7.0~8.0时TP去除率较高;DO1 mg/L时,混凝剂投加量越大,TP去除率越高,但当DO1 mg/L时,混凝剂投加量与TP去除率没有明显关系。     

基于离散元法的温度静力触探贯入与传热研究北大核心CSCD

温度静力触探是一种新型原位测试方法,可同时获取土体的力学和热学参数,为浅层地温能资源勘查提供技术保障。为研究温度静力触探的贯入与传热机理,通过离散元数值模拟实现了离散元模型的建立和试样的力学和热学参数标定。研究分析了贯入过程中的贯入阻力变化、土体应力场、位移场及位移路径;获得了加热-散热过程中探头加热段与隔热段的温度响应规律以及土体温度场演化,并与室内模型试验进行了对比分析。采集的温度变化曲线通过数据解译反演得到了土体的导热系数,为温度静力触探的贯入-传热机理研究及工程应用奠定了理论依据。研究结果表明:贯入过程中,贯入阻力随深度的增加而增加,且土体颗粒位移范围在距锥身B/2内;传热过程中,探头加热60 s,加热段实现了5.5℃的升温;在加热和散热的初期,探头的温度变化最快,与实验结果相同;利用探头散热温度所反演导热系数为0.330 W/(m·K),误差为6.5%,优于加热数据反演结果。     

DME简化反应模型及其在HCCI燃烧分析中的应用研究

提出了一个可应用于HCCI发动机工作过程研究的DME化学反应动力学简化模型,该模型由28种组分、38个基元反应组成,包括3个子模型,即低温反应和负温度系数区子模型、高温裂解和高温氧化子模型以及甲酸生成过程子模型.通过算例对比分析,该DME简化模型能正确揭示DME燃烧过程主要生成物组分的变化规律,能准确计算DME燃烧过程低温和高温阶段的放热特征时刻,其计算结果与详细机理计算结果吻合.相对于详细机理,简化模型节省了计算时间,为实现化学反应动力学与CFD多维模型耦合的燃烧计算提供了一个可行而有效的途径.     

Effects of mechanical fracturing and experimental trampling on Hawaiian corals

In situ trampling occurred under experimental conditions to quantify the differences in the responses to anthropogenic trampling in four dominant species of Hawaiian corals, Porites compressa, Porites lobata, Montipora capitata, and Pocillopora meandrina. Trampling was simulated daily for a period of nine days at which time further breakage was minimal. Forty treatment colonies produced 559 fragments. Trampling was followed by an 11-month recovery period. Coral colony and fragment mortality was low. All four species were highly tolerant of inflicted damage, suggesting that some species of corals can withstand limited pulse events that allow time for recovery. Growth rates following trampling were significantly lower in the treatment groups for three of the four species. This study demonstrated that very few trampling events can produce significant changes in growth even after a long recovery period. Survivorship of fragments is clearly size- and species-dependent in M. capitata and P. compressa. Smaller fragments (<5 cm) had higher mortality than larger fragments (>5 cm). High breakage rates for M. capitata and P. compressa are consistent with the nearshore, low-energy regions they inhabit—the same environment frequented by skin divers and waders. Mechanical tests were conducted to determine tensile and compressive strengths. Pocillopora meandrina exhibited the strongest skeletal strength, followed in decreasing order by Porites lobata, Porites compressa, and Montipora capitata. The skeletal strength obtained from the experiments correlate with the wave energy present in the environments in the regions they inhabit, suggesting that structural strength of corals is an adaptive response to hydraulic stress.     

A STATISTICAL APPROACH TO ASSESS FACTORS AFFECTING WATER CHEMISTRY USING MONITORING DATA1

ABSTRACT: A method to partition the variation in concentrations of water chemistry parameters in a river is described. The approach consists of fitting a family of curves for each chemical parameter. Each curve indicates the response of the parameter to river flow for a particular time period or location. An analysis of covariance is then used to identify statistically significant differences between curves. Such differences result largely from two factors: (1) the discharge of effluents and (2) river flow-concentration relationships. The deviations from the fitted curves indicate month-to-month variations unrelated to river flow that are controlled by factors such as temperature-related seasonal patterns. Underlying statistical assumptions are discussed with respect to water chemistry data. The technique is applied to a data set consisting of monthly samples of 22 water chemistry parameters from the Sulphur River of Texas and Arkansas. Several patterns of response to river flow and to two effluent discharges were revealed.     

苏州市水环境质量调查

简述了1990年—2000年苏州市区水系的变化及京杭运河苏州段沿岸主要工业污染源的变化，对苏州市区水环境质量的变化进行了分析。指出，苏州市区水环境质量的变化主要受水系的改变和污染源防治的共同影响。提出，除继续加强对工业污染源的防治外，还需对水系范围内的生活、农业等方面产生的污染进行防治；在规划水利建设工程时，应将水环境质量的改善与生态建设全面地比较与评价，按其结果再实施工程建设；已建成的环太湖闸在不影响其主要功能的情况下，应保持开启，让优质的太湖水补给运河，从根本上改善苏州市区水环境质量。     

青岛市海况与海洋灾害应急信息管理系统研究

着重考虑了针对青岛地区影响较大的风暴潮、灾害性海浪和赤潮等灾害所构建的应急系统的框架,简要介绍了系统的建设目标、建设内容和实现的功能,并详细阐述了专题数据的内容和来源及数据库的管理和更新机制.     

粤港澳大湾区典型潮间带环境多介质中Cd形态空间分布特征及其影响因素

在粤港澳大湾区典型潮间带开展了 14个站位同步采样和观测,分析各采样点表水、孔隙水、悬浮物和沉积物中Cd形态的空间分布特征,并结合环境因子采用统计分析方法探讨不同介质中Cd形态分布差异的影响因素.结果表明,各潮间带环境表水、孔隙水、悬浮物和沉积物中Cd含量范围分别为0.41～15.03 μg·L-1、0.41～27.5...     

清洁生产战略在开发区层次应用的探讨

根据区域清洁生产特点,结合佛山禅城高新技术开发区环境影响评价过程,探讨开发区层面上实施清洁生产战略在项目准入门槛制定中的可行性,并进行实例应用研究。