高效液相色谱-串联质谱法同时测定海洋沉积物中27种有机磷酸酯

应用广泛且具有毒性的有机磷酸酯(organophosphate esters,OPEs)类阻燃剂,通过水、气输送等多种途径进入海洋环境,可能会导致人类和海洋生物面临潜在的健康风险。因此,建立高效可靠的分析方法对于揭示OPEs在海洋环境中的赋存状况,评估其生态风险具有重要的科学意义。文章建立了同时测定沉积物中27种OPEs的超声提取、固相萃取(SPE)净化以及高效液相色谱-串联质谱(HPLC-MS/MS)检测的分析方法。结果表明:30mL乙酸乙酯(EA)和乙腈(ACN)混合溶剂(体积比为3︰7)的提取效果明显优于单独使用甲醇(MeOH)、二氯甲烷(DCM)、EA和ACN;用5mL EA经LC-C18固相萃取小柱洗脱两次回收率最好;以MeOH和含0.0025%甲酸的水溶液作为流动相时,质谱离子丰度最高。27种OPEs的线性范围为5~500 ng/g (R²>0.99),方法检出限(MDL)范围为0.004~1.250 ng/g,定量限(LOQ)为0.01~4.17 ng/g。三个加标水平(低、中、高)基质加标样品的平均回收率在45%~130%之间,相对标准偏差(RSD)最高11.0%,表明此方法可靠,精密度和灵敏度较高。采用优化的方法分析我国长江口、杭州湾入海口以及东海和黄海交界处海域表层沉积物中OPEs的含量,共检出了21种OPEs,浓度范围为9.83~48.70 ng/g,平均浓度为28.40 ng/g。该方法检测结果高效准确,可用于海洋沉积物中27种OPEs的同时测定。     

利用小波方法分析新43泉气氡异常特征

2010年7月2日、2012年1月8日先后在新疆和硕县境内发生MS4.7和MS5.0两次地震,新43泉距两次地震震中均小于200 km,利用小波变换对气氡资料进行分析后发现,两次地震前3～6个月气氡资料出现异常.又对2012年轮台、和静两次5级以上震例进行验证,结果令人满意,认为小波分析方法是地震前兆数据处理的一种有效方法.     

A statistical model for karst spring discharge estimation under extensive groundwater development and extreme climate change

ABSTRACT

To acquire better understanding of spring discharge under extreme climate change and extensive groundwater pumping, this study proposed an extreme value statistical decomposition model, in which the spring discharge was decomposed into three items: a long-term trend; periodic variation; and random fluctuation. The long-term trend was fitted by an exponential function, and the periodic variation was fitted by an exponential function whose index was the sum of two sine functions. A general extreme value (GEV) model was used to obtain the return level of extreme random fluctuation. Parameters of the non-linear long-term trend and periodic variation were estimated by the Levenberg-Marquardt algorithm, and the GEV model was estimated by the maximum likelihood method. The extreme value statistical decomposition model was applied to Niangziguan Springs, China to forecast spring discharge. We showed that the modelled spring discharge fitted the observed data very well. Niangziguan Springs discharge is likely to continue declining with fluctuation, and the risk of cessation by August 2046 is 1%. The extreme value decomposition model is a robust method for analysing the nonstationary karst spring discharge under conditions of extensive groundwater development/pumping, and extreme climate changes.

Editor D. Koutsoyiannis; Associate editor J. Ward     

带调谐液体阻尼器结构的有限元模拟分析

调频液体阻尼器(TLD)作为一种被动耗能减震装置,由于涉及到两种形态的物质之间的相互作用,真实准确地掌握调谐液体阻尼器的减震特性显得尤为困难,因此建立更加精确的流固耦合模型,进而探讨带调谐液体阻尼器结构的抗震性能是一件非常有意义的工作.本文利用ADINA有限元分析软件分别建立了结构动力学模型和流体动力学模型,并利用其流一固耦合分析模块,对此耦合模型进行瞬态分析,模拟计算结果与试验简化模型的结果具有较好的一致性.在此基础上通过动力时程分析得到了调谐液体阻尼器流场的变化特性,并结合流场特性考查了频率比、地震动、质量比这三个因素对带调频液体阻尼器结构抗震性能的影响,对比分析表明频率比对TLD的减振性能的影响最为显著,最后给出了TLD的设计建议.     

Stable isotope‐based mean catchment altitudes of springs in the Lebanon Mountains

Stable isotopes of water are known to provide information on mean altitudes of spring recharge areas, which is an important parameter for groundwater resources management especially in karstic environments. Very often, a lack of precipitation input data limits the possibility for an appropriate estimation of mean catchment altitudes. In the Jeita spring catchment, Lebanon, a characterization of precipitation input was possible with samples collected at six stations at varying altitudes (88 amount‐weighted monthly samples). A local meteoric water line for the Jeita spring catchment was characterized as δ²H = 6.04 * δ¹⁸O + 8.45 (R ² = .92) for a 2‐year observation period between October 2012 and September 2014. Integral samples from the snow layer were collected at 22 sites at altitudes ranging from 1,000 to 2,300 m above sea level at the end of February 2012 and February 2013, when snow height reached a maximum of more than 6 m at the highest peak in the catchment. Water samples were continuously collected from six springs (Jeita, Kashkoush, Labbane, Assal, Afqa, and Rouaiss). Jeita spring water samples were collected additionally in daily time steps during the snowmelt season in 2012. Mean isotope values of the sampled springs range from ?6.8‰ to ?8.2‰, and from ?33‰ to ?44‰, for δ¹⁸O and δ²H, respectively. The stable isotope data show that input variability (space and time, snow cover, and rainfall) has direct impacts on mean altitude estimates of spring catchments. A more profound interpretation of spring response to rainfall for six local springs in the Lebanon Mountains was possible in comparison to four earlier described springs collected in the Anti‐Lebanon Mountains in Syria.     

LNG储罐高低承台桩基础抗震性能对比分析

目前全容式LNG储罐基础常采用低承台和高承台桩基2种形式。采用弹性振动理论,并考虑壳液耦联振动效应,对全容式储罐高、低承台桩基的抗震性能进行对比分析,给出了2种桩基础形式下全容式LNG储罐结构与基础的震动特性,包括自振周期、单桩水平地震力、抗倾覆性能、罐底周边单位长度上的提离力、储液晃动周期以及晃动波高等。分析表明,高承台桩基的水平地震响应大于低承台8.69%、垂直地震响应大于6.34%;低承台桩基的抗倾覆能力比高承台高12.11%,抗提离能力高于高承台储罐11.42%;高承台的自振周期高于低承台;低承台基础结构的抗震能力要优于高承台基础结构。其结论对桩基础全容式LNG储罐的设计与施工具有一定的参考价值。     

An example of application: The ecological “natural flow regime” paradigm in hydroclimatology

According to the concept of “natural flow regime,” introduced and developed in the 1990's in aquatic ecology, streamflow can be described using five basic characteristics: magnitude, frequency, duration, period of occurrence and variability. A sixth could be added to these, namely, distribution curve. Our study, which focused exclusively on the temporal variability of these six characteristics, had these objectives: (1) to compare their stationarity, (2) to determine the links among these characteristics and (3) to analyze, for the first time, their relationship to six climatic indices (Atlantic Multidecadal Oscillation, Artic Oscillation, North Atlantic Oscillation, Niño3.4, Pacific decadal Oscillation and Southern Oscillation Index). To do this, we used the Vermillon River (2670 km²) as an example, analyzing the streamflow of heavy spring floods (equal to or greater than the annual flood streamflow), as measured between 1934 and 2000.     

秦岭北缘断裂带温泉水渗流特征与地震活动水平研究

前人对秦岭北缘断裂带出露温泉水的氢氧同位素、He同位素和SiO2含量进行了计算,得到了温泉水的热储温度和循环深度。在此基础上,运用温度场作用下的热水垂向运移数学模型演算了循环深度和断层带渗透性之间的关系。根据1970～2008年的区域台网资料,对断裂带进行了分段地震活动多参数组合方法分析,并结合历史中强地震(公元前781年～公元2008年)的空间分布特点,分析总结了断层带不同区段渗透特征和地震活动的关系。最后对秦岭北缘断裂带的渗透性成因进行了解释。     

新30号泉水氡映震特征分析

对新30号泉1990年1月1日至2009年5月31日水氡观测资料进行了统计分析。结果表明,新30号泉水氡观测点对温泉地区发生的5级以上中等地震映震效果较好,震前观测到一些异常信息,异常以高、低值脉冲型异常为主,破年变的异常比较可靠,而且均为短期异常。     

北京地区流体观测方法记录到的汶川大地震同震变化

2008年5月12日发生的汶川8.0级巨大地震中,北京地区的一些流体观测仪器记录到了不同程度的同震响应。为了进一步深入研究该次强烈地震对北京地区未来地震活动趋势的影响,系统搜集、整理归纳了该次巨大地震引发的北京地区流体观测仪器记录到的同震响应信息,将北京地区的流体同震现象进行概括,然后分析了数字化流体分钟值观测资料同震效应的表现形态及其变化特征,验证了新安装的一些数字化流体观测仪器的可靠性、灵敏性,对相关流体观测仪器可能存在的一些问题进行了讨论。