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Methylmercury cycling in estuarine sediment pore waters (Penobscot River estuary, Maine, USA)
Methylmercury cycling estuarine sediment pore waters
2014/4/21
Particulate mercury (Hg) sequestered in coastal marine sediments may be efficiently methylated to highly toxic methylmercury (MeHg), thereby placing exposed organisms at risk of MeHg bioaccumulation. ...
A nitrate sink in estuaries? An assessment by means of stable nitrate isotopes in the Elbe estuary
nitrate sink in estuaries stable nitrate isotopes Elbe estuary
2014/4/18
To elucidate the fate of river-borne nitrate in the estuarine environment, we measured nitrate concentrations and d15N andd18O of nitrate along the salinity gradient in the estuary of the river Elbe, ...
Mate limitation in an estuarine population of copepods
Mate limitation estuarine population copepods
2014/4/18
We determined the probability of mating as a function of population density in the estuarine copepodAcartia hudsonicaby combining experimental measurements with a simple model. Pairs of unmated copepo...
A comparative study of carbon dioxide degassing in river- and marine-dominated estuaries
carbon dioxide degassing river- and marine-dominated estuaries
2014/4/18
The partial pressure of carbon dioxide (pCO2), concentration of total dissolved inorganic carbon, and total alkalinity were measured at both high tide and low tide in the surface water of three Georgi...
Propulsive performance and flow field characteristics of a 2-D flexible fin with variations in the location of its pitching axis
analytic network process (ANP) underwater multi-target tracking decision tracking logic
2011/9/13
The thrust coefficients and propulsive efficiency of a two-dimensional flexible fin with heaving and pitching motion were computed using FLUENT. The effect of different locations of the pitching axis ...
Valuable mineral resources are widely distributed throughout the seabed. autonomous underwater vehicles (AUVs) are preferable to remotely-operated vehicles (ROVs) when probing for such mineral resources as the extensive exploration area makes it difficult to maintain contact with operators. AUVs depend on batteries, so their power consumption should be reduced to extend exploration time. Power for conventional marine instrument systems is incorporated in their waterproof sealing. External intermittent control of this power source until termination of exploration is challenging due to limitations imposed by the underwater environment. Thus, the AUV must have a power control system that can improve performance and maximize use of battery capacity. The authors developed such a power control system with a three-step algorithm. It automatically detects underwater operational states and can limit power, effectively decreasing power consumption by about 15%.
surface piercing propeller boundary element method hydrodynamic characteristics
2011/9/13
Demand for high-speed marine vehicles (HSMVs) is high among both commercial and naval users. It is the duty of the marine vessel’s designer to provide a hull and propulsion system that diminishes drag...
GIWA（国际水域全球评估计划）是由联合国环境计划署主持的一个水文考察项目，其总体目标是研究出一套综合的战略性评估体系，供GEF及其协作单位用于鉴别国际水域或跨境水域的有关问题的轻重缓急，以便安排相应的补救措施和缓解措施，取得在国家、区域和全球水平上的显著环境效益。该评价在实施过程中，综合考虑与人类发展过程密切联系人口统计、经济和社会变化等方面的因素，预测未来条件下的发展趋势。
滇-黔边境鲁甸沿河铜矿床矿化受二叠纪玄武岩最上部古火山口相角砾凝灰岩-气孔状熔岩和上覆宣威组碳泥质层控制。矿石矿物主要为自然铜、氧化铜与辉铜矿。自然铜呈板片状、网脉状、浸染状产出。矿化与阳起石化、沥青化、硅化和沸石化密切相关。在峨眉山大火成岩省寻找沿河式铜矿应关注以下重要问题：①地球化学急变带所确定的岩石圈不连续界面控制了峨眉山玄武岩裂隙式喷发；②古火山口相从苦橄质到安山质高分异岩浆喷发；③火山口...
Abstract根据最近50余年资料研讨黄河、长江月平均流量的特征，揭示其若干演变规律。分析得出：长江中下游多年平均年流量约为黄河的20倍。初夏（6月）时，则接近50倍。黄河的大流量主要集中出现于 7～10月，这 4个月平均月流量为全年的14．5％，其它 8个月平均为 5．25％；长江流量自 5月起逐渐增加，5～10月平均月流量占全年的12．0％，其它各月平均为 4．67％。最近50余年来，黄河中...
天山乌鲁木齐河源1号冰川雪坑中pH值和电导率的季节变化及淋溶过程
2007/12/12
Abstract10 μm）微粒的浓度峰值提前40天左右；在有的雪坑中，pH值和电导率的峰值出现在污化层附近，与污化层的位置有较好的一致性，说明污化层对可溶性离子的淋溶作用可能有一定的影响。相关分析表明，Ca2+是影响表层雪中pH值和电导率变化的最主要离子。
Abstract在全球变暖的背景下，我国多数大江大河源区存在冰川退缩、雪线上升以及多年冻土和季节冻土明显退化等现象，并由此造成河源区产流量减少以及生态环境恶化等诸多问题，这在内陆河山区流域体现的较为明显，但目前分布式水文模型中很少涉及冻土水热耦合问题。文章以黑河干流山区流域为例，构建了一个内陆河高寒山区流域分布式水热耦合模型（DWHC）。模型基于土壤水热连续性方程将流域产流、入渗和蒸散发过程融合起...
Abstract以黑河出山日平均流量作为对比，利用26个降水站点、11个气温站点和14个潜在蒸发站点2000年日资料，模型设计了6套气象因子空间分布方案，进行数值模拟试验，结果表明，在黑河流域现有观测站点的情况下，利用各种空间插值方法所得结果基本相当，考虑地面高程的三维插值与不考虑地面高程的二维插值结果相差不大，补充距离研究区较远的站点观测资料，模型结果反而变差。最终模型采用基于二维算法的最近距离...
中国南方岩溶地下河系形成演变的链式规律
中国南方 岩溶地下河系 链式规律
2007/12/12
Abstract在分析中国南方岩溶区地下河系形成与发育的现存问题的基础上，提出了岩溶地下河系形成演变的链式规律，并加以详细评述，为今后岩溶地下河系水能调控空间定位与水资源开发提供相关理论与方法。