水深测量误差分析与改正

影响水深测量精度的因素较多,水深测量误差主要有仪器误差、声速误差、潮位观测误差、船速误差和船只因素,较全面进行了测量误差原因分析,针对作业过程,提出采取提高测量精度措施,并通过应用实例说明应用注意事项。     

地表一致性静校正量误差分析

目前,在生产中广泛使用的静校正方法几乎都是基于地表一致性假设的。在地表复杂地区,地形起伏较大,低速带厚度和横向速度变化较大,地表一致性假设往往与实际地质情况不符,在这种情况下再运用地表一致性静校正,势必产生很大的误差。笔者利用模型正演方法着重讨论复杂地区地表一致性静校正误差存在的原因及这种原因跟基准面、炮检距、低速带和基岩速度、低速带厚度、反射面深度等之间的关系,分析其变化规律,提出解决复杂地区静校正问题的建议,以期改进现有的静校正方法,达到减小误差的目的。     

Interaction of solitary waves with emergent, rigid vegetation

In this study, solitary wave interaction with emergent, rigid vegetation was studied numerically and experimentally. Laboratory experiments were carried out in a wave flume with vegetation models of different lengths and porosities; the Boussinesq equations with the effects of the vegetation being modeled by a quadratic drag law are used to simulate the wave scattering by and the wave propagation through vegetation. Effects of incident wave height, vegetation density, and vegetation length are discussed. An empirical expression for the mean drag coefficient of emergent, rigid vegetation is presented and compared with other available data. The results are useful for studying tsunami hazard mitigation by coastal forests.     

Determination of discharge coefficients for a cross-flooding duct

Cross-flooding ducts are used to equalize asymmetric flooding and, thus, to decrease the heel angle of a ship in an emergency. The present design guidelines for cross-flooding arrangements involve uncertainties associated with the effect of variable structural factors. In this study, scale model experiments were carried out to determine discharge coefficients of a typical cross-duct, with a focus on the effect of structural components such as the girders, stiffeners, and web frame. Flow conditions and configuration of the components were varied in the experiments. The structural stiffeners in the cross-duct were found to notably increase the discharge coefficient whereas the effects of the web frame and the inclination of the duct at an angle of 7° were negligible. The experimentally obtained discharge coefficient values for the cross-duct were considerably lower than the corresponding values computed according to the generally used guidelines of the IMO Resolution MSC.245(83). This indicates that the geometrical properties of the girders in the cross-ducts need to be properly addressed to avoid overestimating the discharge coefficients. Overall, the experimental results formed an indispensable dataset for the validation and further development of CFD approaches.     

长江三角洲表层土壤Sn元素的空间分布特征 及影响因素

对长江三角洲地区表层土壤Sn含量的空间分布特征进行分析,发现土壤平均含Sn量为8.35mg/kg,远远高于全国A层土壤Sn的背景值2.6mg/kg,表层土壤中Sn空间分布不均匀,呈现由苏锡常、宁镇扬、杭嘉湖、宁绍等经济带增高的趋势。各种沉积环境、土壤类型中Sn的含量也较全国类似或同类沉积环境、土壤类型中Sn的含量高,显示了高背景的特点。人类活动影响强烈区表层土壤中Sn元素富集明显,90.39%的面积区表现出富集的特征,富集系数大于2的强富集区面积占44.03%。另外,Ag、Bi、Hg、P、Pb、Sb、Se、TOC等也与土壤Sn呈相关性,可能与土壤Sn的富集有成因联系。     

An empirical formula for friction coefficient of a perforated wall with vertical slits

The friction coefficient in the permeability parameter of a perforated wall has been estimated on the basis of a best fit between measured and predicted values of such hydrodynamic coefficients as reflection and transmission coefficients. In the present study, an empirical formula for the friction coefficient is proposed in terms of known variables, i.e., the porosity and thickness of the perforated wall and the water depth. This enables direct estimation of the friction coefficient without invoking a best fit procedure. To obtain the empirical formula, hydraulic experiments are carried out, the results of which are used along with other researchers' results. The proposed formula is used to predict the reflection and transmission coefficients of various types of structures including a perforated wall. The concurrence between the experimental data and calculated results is good, verifying the appropriateness of the proposed formula. It is also shown that the proposed formula can be used for irregular waves as well.     

时差对海洋磁力测量地磁日变改正的影响分析

为研究时差对磁测的影响,基于站间同步地磁日变曲线的特征,尝试采用同步比对法和相关分析法计算两站的时差.结论表明:同步比对法和相关分析法能反映站间真实的时差,当测区范围较小时(至少是在本文实例的两个地磁日变站之间),时差对地磁日变改正的影响很小,海洋磁力测量地磁日变改正时可以忽略其影响.     

风沙流中沙粒拖曳力系数研究

 拖曳力系数是计算风沙流中沙粒受空气阻力的重要参数。考虑实际风沙流中沙粒浓度及沙粒形状,利用FLUENT软件首先计算了不同风速下距地表不同高度处两沙粒的拖曳力系数,给出了影响沙粒拖曳力系数的间距范围,然后计算了真实风沙流中不同高度沙粒拖曳力系数。结果表明,给定风速下拖曳力系数随距地面高度的增加先减小后增加,并将沙粒拖曳力系数拟合成距床面高度的函数,该函数与风速有关。     

河南省环境污染的区域差异研究

从"十一五"期间河南省各地区主要污染物排放的实际情况来看,各地区降污减排效果差距明显,环境污染的区域差异问题越来越成为影响河南省和谐社会建设和工业化进程的重要障碍。主要选取了极差、加权变异系数和锡尔熵3个指标,对河南省2006—2009年间的主要污染物排放情况进行了地区差异度分析,旨在为政府制定更加合理的节能指标和部署减排任务提供科学的决策参考。     

河北省灵寿县西石门金矿黄铁矿热电性标型及其找矿意义

河北省灵寿县西石门石英脉型金矿位于华北地台太行隆起区之南东部的阜平矿集区,与该区石湖大型金矿受不同断裂控制。黄铁矿是矿床的主要载金矿物,以4个世代产出于黄铁矿-石英阶段(I)、石英-黄铁矿阶段(II)、多金属硫化物阶段(III)和石英-碳酸盐阶段(IV)等4个成矿阶段,其中,石英-碳酸盐阶段的黄铁矿十分稀少。本矿段黄铁矿单晶热电系数变化范围为-328~341μV/℃,从早期到晚期,4个世代的黄铁矿热电系数离散性先增大再减小,石英黄铁矿阶段（II）离散性最大。从黄铁矿-石英阶段(I)至石英-碳酸盐阶段(IV),黄铁矿热电导型的变化规律是P>N(III)→P>>N (IV); P型黄铁矿热电系数均值αP和出现率P%由浅部到深部,总体为逐渐降低,局部呈波状起伏,与矿石金品位呈正相关关系.黄铁矿的热电系数温标计算和投图表明,该矿床的成矿温度集中在168～330℃,为中低温矿床。热电系数在50—200μV/℃之间的黄铁矿是富金矿段的标志。综合分析认为,该矿床290m以下仍有良好的找矿潜力。