Formaldehyde in the Elbe Estuary: Distribution and Processes

From 1989 to 1992, the concentration of formaldehyde was measured along the Elbe estuary as well as at anchor stations. In mesocosm experiments, the turnover of formaldehyde could be investigated avoiding the variability caused by tidal advection of different water bodies. Formaldehyde concentrations in the Elbe estuary ranged from 0.5… 180 μg/L. As sources, a release by algae and microbial processes were identified. Three areas with different dominance of formaldehyde turnover processes were found in the estuary. In the limnic part of the estuary, a release of formaldehyde by algae was dominant. In the mixohaline zone and the turbidity maximum, bacterial degradation of organic matter increased the formaldehyde concentration. In the mouth of the estuary, the adjacent Wadden sea areas influenced the concentration due to formaldehyde-rich runoff from the tidal mud flats. In the other parts of the estuary, a fast degradation of formaldehyde kept the formaldehyde concentration at a low level. In sediment cores from the Elbe and a mesocosm, the formaldehyde concentrations were in the same range as in the water column. Mesocosms with and without sediment showed no significant differences in concentration levels which were similar to those measured in the Elbe at the same time. During the investigated period, no anthropogenic impacts of formaldehyde into the Elbe estuary could be detected.     

Combined processing of the IGS and the IGEX network

 Since the beginning of the International Global Navigation Satellite System (GLONASS) Experiment, IGEX, in October 1998, the Center for Orbit Determination in Europe (CODE) has acted as an analysis center providing precise GLONASS orbits on a regular basis. In CODE's IGEX routine analysis the Global Positioning System (GPS) orbits and Earth rotation parameters are introduced as known quantities into the GLONASS processing. A new approach is studied, where data from the IGEX network are combined with GPS observations from the International GPS Service (IGS) network and all parameters (GPS and GLONASS orbits, Earth rotation parameters, and site coordinates) are estimated in one processing step. The influence of different solar radiation pressure parameterizations on the GLONASS orbits is studied using different parameter subsets of the extended CODE orbit model. Parameterization with three constant terms in the three orthogonal directions, D, Y, and X (D = direction satellite–Sun, Y = direction of the satellite's solar panel axis), and two periodic terms in the X-direction, proves to be adequate for GLONASS satellites. As a result of the processing it is found that the solar radiation pressure effect for the GLONASS satellites is significantly different in the Y-direction from that for the GPS satellites, and an extensive analysis is carried out to investigate the effect in detail. SLR observations from the ILRS network are used as an independent check on the quality of the GLONASS orbital solutions. Both processing aspects, combining the two networks and changing the orbit parameterization, significantly improve the quality of the determined GLONASS orbits compared to the orbits stemming from CODE's IGEX routine processing. Received: 10 May 2000 / Accepted: 9 October 2000     

ICP—AES测定白钨矿中的十五种元素

样品用HCl分解,并沉淀分离除去W,除W后残渣碱熔,合并液用ICPQ-1000型光量计同时测定Mg、Ca、V、Cr、Mo、Mn、Fe、Cu、Zn、Si、Al、Pb、Sr、Ba和P 15种元素,各组份测定的RSD<10％。同时,本文还讨论了测定中元素间的干扰效应。     

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江苏中、南部及邻区地震重新定位及在断层研究中的应用

本文分析了地震相对定位的双差法和地壳结构与定位联合反演方法的优势与局限性,在联合反演中用遗传算法最优化,将上述两种方法结合,对江苏省中南部和相邻地区进行地震重新精定位.先对研究区进行地壳结构与定位联合反演,然后用得到的地壳结构,用双差法进行相对定位.就该区主要断层的平面分布及与地震的关系,溧阳6.0级地震、南黄海6.2级地震、常熟-太仓5.1级地震的震源深度与发震构造,常熟一张家港间震群的震源深度进行了分析讨论.     

后续地震类型及其特征分析

对中国大陆５．０级以上强震的后续地震进行了分析,按成因将其划分为剩余型、诱导型和后生型３类。讨论了３种后续地震的主要特征及其在大震震源机理研究和地震预报中的意义。     

利用天基测角资料进行定轨的方法初探

利用观测得到的测角资料确定目标星的轨道,具有非常重要的应用价值.为了解决该问题,首先给出了最优化数学模型STSM,其次,利用测角资料进行多项式拟合,给出求解最优化模型STSM所必需的初始值计算方案,再次,对STSM目标函数的性态进行了详细地分析,并据此给出了求解该优化问题的基本方法.最后,将上面的方法付诸实施,进行了大量的仿真计算,并对仿真结果进行了初步地分析.计算结果表明,在一定的精度和稀疏度的限制之下,根据方案使用天基测角数据确定目标星的轨道根数既可行又稳健.     

A Preliminary Study of Chromophoric Dissolved Organic Matter (CDOM) in Lake Taihu,a Shallow Subtropical Lake in China

The optical properties and spatial distribution of chromophoric dissolved organic matter (CDOM) in Meiliang Bay of Lake Taihu were evaluated and compared to the results in literature. Concentrations of dissolved organic carbon (DOC) ranged from 8.75 to 20.19 mg L^?1 with an average of (13.10 ± 3.51) mg L^?1. CDOM absorption coefficients a(λ) at 280 nm, 355 nm, and 440 nm were in the range 11.28...33.46 m^?1 (average (20.95 ± 5.52) m^?1), 2.42...7.90 m^?1 (average (4.92 ± 1.29) m^?1), and 0.65...2.44 m^?1 (average (1.46 ± 0.44) m^?1), respectively. In general, CDOM absorption coefficient and DOC concentration were found to decrease away from the river inflow to Meiliang Bay towards the lake center. The values of the DOC‐specific absorption coefficients a*(λ), given as absorption coefficient related to mass concentration of organic carbon (C) ranged from 0.28 to 0.47 L mg^?1 m^?1 at 355 nm. The determination coefficients between CDOM absorption and DOC concentration decreased with the increase of wavelength from 280 to 550 nm. The linear regression relationship between CDOM absorption at 280 nm and DOC concentration was following: a(280 nm) = 1.507 L mg^?1 m^?1 · DOC + 1.215 m^?1. The spectral slope S values were dependent on the wavelength range used in the regression. The estimated S values decreased with increasing wavelength range used. A significant negative linear relationship was found between CDOM absorption coefficients, DOC‐specific absorption coefficients and estimated S values especially in longer wavelength range. The linear regression relationship between DOC‐specific absorption coefficients at 440 nm and estimated S values during the wavelength range from 280 to 500 nm was following: a*(440 nm) = (–0.021 μm · S + 0.424) L mg^?1 m^?1.     

ICP-AES测定海洋生物体中13种元素的微波消解条件优化

报道了微波密闭消解正交试验条件优化电感耦合等离子体发射光谱法(ICP-AES),同时测定8种海洋生物体中硒、铁、锰、锌、钙、镁、锶、砷、镉、铬、铜、铅和镍等13种元素含量的实验结果。优化后的样品消解条件为加入的HNO3V:H O2 2V=6.0 mL:1.0 mL,第二步程序升温温度为170℃,消解时间20 min;测定标准曲线相关系数大于0.999,相对标准偏差为0.30%~2.55%,加标回收率为92.0%~104.8%,方法检出限为0.0010~0.0468μg/g。结果表明,优化后方法测定操作简便、具有高的灵敏度、准确度和精密度,且能多元素同时测定,适合于海洋生物样品中这些元素含量的准确测定,并可为评估海产品食用安全提供科学依据。     

路基土干湿类型判定的若干问题浅析

市政道路工程勘察中,路基土干湿类型的判定结论为道路设计提供了设计依据。本文分析比较了相关规范给出的路基土干湿类型的判定标准,并结合市政道路工程勘察实践,提出了路基土干湿类型判定中,存在的若干问题和注意事项,供同行专家讨论、指导。