Diagnosis of river basins as CO2 sources or sinks subject to sediment movement

Sediment movement during erosion, transport and deposition greatly affects the ecosystem of river basins. However, there is presently no consensus as to whether particular river basins act as carbon dioxide (CO₂) sources or sinks related to these processes. This paper introduces a rule‐of‐thumb coordinate system based on sediment delivery ratio (SDR) and soil humin content (SHC) in order to evaluate the net effect of soil erosion, sediment transport and deposition on CO₂ flux in river basins. The SDR–SHC system delineates CO₂ source and sink areas, and further divides the sink into strong and weak areas according to the world‐average line. The Yellow River Basin, most severely suffering soil erosion in the world, only appears to be a weak erosion‐induced CO₂ sink in this system. The average annual CO₂ sequestration is ~0·235 Mt from 1960 to 2008, a relatively small value considering its 3·1% contribution to the World's sediment discharge. The temporal analysis shows that the Yellow River Basin was once a source in the 1960s, but changed its role to become a weak sink in the past 40 years due to both anthropogenic and climatic influences. The spatial analysis identifies the middle sub‐basin as the main source region, and the lower as the main sink. For comparison, sediment‐movement‐related CO₂ fluxes of eight other major basins in four continents are examined. It is found that the six basins considered in the Northern Hemisphere appear to be sinks, while the other two in the Southern Hemisphere act as sources. Copyright © 2012 John Wiley & Sons, Ltd.     

强震人员损失回归预测方法

在回顾近年对地震人员损失预测的研究工作的基础上,根据USGS的PAGER系统中地震人员损失回归模型,利用发生在1970-2008年间的128条地震现场调查灾害记录建立了我国东、西部区域适用的地震人员损失预测模型;并利用发生在1980-2007年间的234条地震损失记录建立了地震人员重伤数与人员死亡数的回归关系;最后利用模型对2008年四川汶川地震的人员损失进行评估计算,得到了与实际震害损失相接近的评估结果。     

广东信宜1、2号井水温的同震响应及机理初步探讨

介绍了信宜1、2号井水文地质环境,总结了近年来两井水温的同震响应现象,并对其机理进行了初步的探讨。认为两口井的同震响应虽然形态不一致,但机理是相近的,主要是由于地震波的扰动,随着振动效应的作用,加大了不同含水层间的垂直运动速率,而产生水温上升或下降现象,震后一段时间随着混合通道的闭合或运动速率的恢复,2号井的水温逐渐恢复到原有的水平上。     

全国自动地震速报系统综合评估

通过对2011年1月1日至12月31日的3套独立自动地震定位系统结果进行综合处理,得出中国自动地震综合目录,并与正式速报结果进行对比,得出全国自动地震速报系统综合评估结果,发现该目录对于国内绝大部分5级以上、国外7级以上地震实现整体覆盖,且没有误报发生,可以作为国家台网中心正式地震速报的重要参考,对于建立“自动报～正式报”的两级地震速报制度可提供技术支撑。     

沈阳站电离层F2层临界频率变化特征

本文对沈阳站电离层测高仪2009—2012年观测数据的月均值进行了统计分析,揭示了沈阳站电离层F2层临界频率的日变化和年变化特征。     

基于遗传算法和统计学的电阻率测深二维反演研究

本文介绍了一种以遗传算法和统计学为基础的反演方法,该方法利用一维反演结果的统计学特征确定地层电性结构并设计初始模型,使用遗传算法修改模型,经过二维有限单元法正演达到拟合误差最小,从而完成电阻率测深数据的二维反演.这个方法的优点在于不需要解大型线性方程组,降低计算量,先判断地层电性结构,反演后给出用地电断面表示的直观的解释结果.理论模型试算和模型实验证明该方法效果较好.     

基于星载GPS的HY-2卫星高精度精密定轨模拟研究(英文)

HY-2卫星是我国第一颗测高卫星,其径向定轨精度要求厘米量级,搭载了星载GPS接收机。目前HY-2还处于测试阶段,没有公布观测数据。为了确定基于星载GPS的HY-2精密定轨流程及其定轨精度,本文模拟了HY-2卫星星载GPS观测数据,结果表明HY-2星载GPS天线每个历元至少观测7颗GPS卫星。给出了基于星载GPS的精密定轨流程,分别采用简化动力学方法和动态几何法进行了精密定轨实验。对于相位1mm和3mm随机误差的相位观测数据,简化动力学法和动态几何法定轨都能够实现厘米量级的径向精密定轨,几何法定轨精度略低于简化动力定轨。地球重力场模型是影响HY-2卫星精密定轨的重要因素,本文对不同阶次的重力场模型EIGEN2、EGM96、TEG4和GEMT3进行了简化动力学定轨实验,高于50阶次的重力场模型都能够实现厘米级径向精密定轨,主要原因在于大量的高精度星载GPS观测数据和重力场模型精度的提高。     

Photocatalytic Decolorization Kinetics and Mineralization of Reactive Black 5 Aqueous Solution by UV/TiO2 Nanoparticles

The photocatalytic decolorization and mineralization of Reactive Black 5 (RB5) dye in presence of TiO₂ Degussa P25 has been studied using artificial light radiation in a shallow pond slurry reactor. The equilibrium adsorption of dye, influence of pH (3–11), catalyst load (0.5–3.0 g/L), and dye concentration (20–100 mg/L) on decolorization kinetics were studied. The effect of area to volume ratio of photoreactor on decolorization kinetics has been also studied. Mineralization studies were performed at optimized conditions of pH (3) and catalyst load (1.5 g/L). The maximum adsorption (26.5 mg/g) of dye was found to occur at pH 3. The apparent pseudo first order decolorization rate constant (k_app) value followed the order pH 3 > pH 11 > pH 9 > pH 7. As compared to available literature reduction in total organic carbon (TOC) was minimal by the time there was complete decolorization. Initial reduction in TOC was followed by subsequent increasing trend till complete decolorization. Final decreasing trend in TOC was observed only after complete decolorization. Twelve hours of treatment under experimental conditions reduced TOC content by 70% only. Discussion of results suggest that photocatalytic treatment of colored effluent under low UV intensity, and low A/V ratio may result in completely decolorized effluent but still having high COD.     

Synthesis and Characterization of Poly(2‐hydroxyethylmethacrylate‐hydroxyapatite) a Novel Composite for the Removal of Lead(II) from Aqueous Solutions

In the present study, a novel adsorbent, poly (2‐hydroxyethylmethacrylate‐hydroxyapatite) [P(HEMA‐Hap)], was prepared and characterized. The synthesis was achieved by means of free‐radical polymerization and a number of structural characterization methods, including FT‐IR, XRD, TGA, SEM, BET‐porosity, and swelling tests. Pb²⁺ adsorption was performed using a series of pH, time, and temperature ranges. The reusability of the composite was also tested. The results obtained indicated that the novel adsorbent is able to bind Pb²⁺ ions with strong chemical affinity. The adsorption results were fitted to the classic Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) sorption models. Thermodynamic parameters obtained demonstrated that the sorption process was spontaneous (ΔG < 0), endothermic (ΔH > 0), as expected. The process was also consistent with the pseudo‐second‐order model, and chemical adsorption was determined to be the rate‐controlling step. It was also shown that the composite could be used for five consecutive adsorption processes.     

基于线粒体COⅢ基因分析厚壳贻贝(Mytilus coruscus)养殖群体遗传多样性

基于线粒体DNA的COⅢ基因序列对我国沿海重要经济贝类厚壳贻贝3个养殖群体(温州、宁德、福州)的遗传多样性和遗传结构进行了分析。由PCR扩增获得23个体的COⅢ基因787bp的部分序列,其多态性遗传参数统计显示,23个个体共检出21个单倍型,总群体单倍型多样性指数(Hd)为0.978,核苷酸多样性指数(Pi)为0.01045,平均核苷酸差异数(K)为8.534,三个群体均显示出较丰富的遗传多样性。遗传分化系数(Fst)表明,福州群体与宁德群体和温州群体间有一定程度的遗传分化,而宁德群体和温州群体间无遗传分化。