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991.
为探究强壮箭虫(Sagitta crassa)在黄河口及其邻近水域的时空分布特征及其与生物和非生物环境等因子的关系,本文依据2013—2014年在黄河口及其邻近水域6个航次的调查数据,采用丛生指标(I)、聚块性指标(A)和负二项分布参数的倒数(CA)等聚集指标,分析了强壮箭虫的空间分布特征;应用广义可加模型(GAM)研究了强壮箭虫密度的时空分布和环境因子的关系。结果表明,黄河口及其邻近水域强壮箭虫平均密度为21.85 ind/m3,春、秋季高,冬、夏季低;其密度的空间分布以黄河入海口附近水域为密集中心,向远岸水域逐渐降低;强壮箭虫在黄河口及其邻近水域的聚集特征随密度的变化存在两次聚集和两次扩散;水深、表层水温和浮游桡足类密度是影响其密度时空分布的主要因子,总偏差解释率为55.11%,强壮箭虫密度随水深的增加而减小,随表层水温的升高先增加后减小,随桡足类密度的增加而增加。强壮箭虫密度受黄河口及其邻近水域环境因子变动的影响,具有明显的季节变化和空间分布规律。 相似文献
992.
本文提出一种利用区域形状匹配技术来实现数字图象的自动对位的方法。利用对噪声和畸变相对稳定的弦分布形状匹配法,建立由待定位图象中分割出来的区域之间的相似关系。用概率松弛标签算法优化和确认匹配,进而得出对位所需的变换参数。分析和实验均表明:这种方法对有未知比例,位移和旋转变化的图象的对位效果良好。 相似文献
993.
This article deals with the interaction of zinc with δ−MnO2, γ−MnOOH and manganite existing in natural water systems. The mechanism of the reaction has been studied in detail. From
the fact that the “ratio of ion exchange(%)-pH” graph is an “S shaped” curve, it is possible to deduce that the chemical reaction
is of the nature of cation exchange. And since the pH range of ion exchange=4, it is possible to further deduce that the reaction
can be explained by the mechanism of monovalence cation exchange.
The main result of this article is the discovery of a new type of isotherm which has not been mentioned in previous literature
here and abroad. This isotherm cannot be represented by any presently available adsorption isotherm equations in marine chemistry.
The characteristics of this new type of isotherm are as follows: the isotherm has two “knees” and three “plateaus”, the heights
of these three “plateaus” are in the ratio 1:2:3. In order to explain theoretically our new isotherm, this article suggests
the application of the principle of interfacial stepwise ion exchange for liquid-solid distribution of minor elements on suspended
particulate matter. The corresponding isotherm equation was derived from this theory.
The results obtained in this article will be of theoretical guiding significance in the study of the marine geochemistry of
zinc.
Projects supported by the Science Fund of the Chinese Academy of Sciences. 相似文献
994.
It is apparent that there is a difference between mud coasts and sand coasts in such aspects as sediment components, hydrodynamics
of nearshore waters, and the formative process in configuration, and profile. The intensity distribution of waves affecting
the mud flats in Lianyungang, and the conditions determining tidal water levels, are discussed in this paper. A mathematical
model which describes the erosion process of mud flats has been derived on the basis of the results of tests for the mud process
in seawater. The model is satisfactory for the actual mud flat profile change in Lianyungang with artificial mud discharges. 相似文献
995.
In seawater, aside from metal elements and suspended particles, organic substances amount to about 500–2,000 ug carbon/l[8], which is not neglegible in comparison with that of minor metal elements. But in the study of the interaction of the three
constituents (metal elements, organics, and suspended particles), the effect of organics in seawater on the surface reaction
of metal element—suspended particles has usually been neglected. Recent theoretical research[1, 11] confirmed the importance of the effect of organics in seawater on the surface reaction of metal element—suspended particles.
Generally, the effect of organics on the reaction of metal ions, especially Cu(II), on a solid surface is either promotive[2] or inhibitive[7, 9]. So far the fact that organics cannot affect the surface reaction of Cu(II) ions on solids has not been reported in literature.
Our experimental results showed that none of the amino acids in seawater affect Cu(II)-goethite ion exchange under certain
experimental condition (such as amino acid of lower concentration and lower pH). It was known that the metal ion-organics
complex in a liquid competing with solids for metal ions may inhibit the surface reaction of metal ions on solids, but the
mechanism of the complex reaction of metal ions competing with solids is not known yet. In fact, the decrease of surface site-exchanging
due to the surface reaction of organics on solids is also inhibitive. It is also explained by the ion exchange isotherm of
the “amino acid-Cu(II)-geothite” system. This result further demonstrates that the theory of interfacial stepwise ion exchange
is applicable to the metal ion exchange isotherm with the presence of organic substances in the system.
Projects supported by the Science Fund of the Chinese Academy of Sciences 相似文献
996.
997.
胶州湾菲律宾蛤仔死壳分布与生态环境关系的研究 总被引:1,自引:0,他引:1
胶州湾菲律宾蛤仔栖息地带由于近年受拖耙捕生产,底质遭到频繁骚动。同时沿岸带局部水域环境污染严重,以及河口盐度突发性骤降等因素,直接影响了蛤仔的存活率。因而蛤仔死壳逐年增多。据1990年调查,9月份幼蛤和成蛤死壳平均密度比同年4月分别增加3.5倍和1.8倍,蛤仔资源量亦受一定损失。 相似文献
998.
Problems with biogenic silica measurement in marginal seas 总被引:5,自引:0,他引:5
Surface sediment samples from the Bohai, Yellow Sea, and the Pacific were used to assess biogenic silica (BSi) content and to study uncertainties in BSi measurements. The contents of BSi in the Bohai and Yellow Sea are all less than 1%. The dissolution of BSi in sediments from the Bohai and Yellow Sea is very important to maintain high levels of silicate in the water column. The non-biogenic silica from clay minerals has an obvious effect on BSi of sediment samples in the Bohai and Yellow Sea with low BSi and high clay minerals. The solid to solution ratio was found to have a great influence on BSi measurement, which can induce uncertainties up to 75%. The effect of loss by sorption and centrifugation is negligible. Interlaboratory comparison of techniques for BSi measurement by the wet alkaline extraction technique of Mortlock and Froelich [Deep-Sea Res. 36 (1989) 1415-1426] with clay correction was suggested to give no significant differences. However, differences in sediment compositions and reagent to sample ratio may limit the application of the wet alkaline extraction method. 相似文献
999.
研究了麻城地区重、磁异常场特征,经反演计算获得了深部结构特征。对重力布格异常利用Parker-Oldenburg快速位场反演方法计算出莫霍面的展布,对航磁异常利用对数功率谱法和矩谱法计算出居里面深度。在此基础上,探讨该震区深部蕴震条件。主要结论是:①麻城-团凤断裂带为该区切割较深的主要控震构造;②1932年麻城6.0级地震发生在区域重力异常等值线梯度最大处,磁力异常区两局部正异常间的低值带,莫霍面及居里面隆起区边缘;③发震部位有其特定的深部蕴震构造及应力蕴震条件。 相似文献
1000.
本文探讨了利用地震矩反演断裂形变带运动学参数的基本理论和方法,将其初步应用于鲜水河断裂形变带变形分析和运动机制的研究。结果表明,鲜水河断裂带呈现出走向拉伸、倾向压缩的形变格局,由地震矩反演的断裂带剪切形变速率(10.9mm/a)与用地质学估算方法(17mm/a)和现今地壳形变测量(8mm/a)的结果相当。同时,反演出的应变主方向能解释鲜水河断裂现今活动分段性特征以及多种滑动方式共存的现状,从而证明该方法是目前研究区域运动学问题切实有效的手段之一。 相似文献