贝类育苗中几种水处理新方法应用的探讨

本文主要叙述磁化水、泡沫处理水、臭氧处理水、高分子重金属离子吸附剂在贝类育苗上的应用，介绍其使用方法、优点和不足，从而为贝类人工育苗创造出一个良好的水环境，使贝类育苗稳产高产。     

桶形基础及其作用下的粉质土海床失稳机制研究的试验设计

在阅读、分析以往的有关资料的基础上 ,结合实际的试验条件 ,对桶形基础及其作用下的粉质土海床失稳机制研究的试验作出了专门设计。该设计通过配土、设计模型桶基和负压沉贯的操作过程、设置孔压传感器等实验手段 ,努力从土体破坏的角度 ,寻求负压沉贯过程中沉贯负压、沉贯阻力及孔隙水压力之间的变化关系和确定桶基的上拔力。并且指出了数据处理的基本思路 ,以利于课题的深入研究。     

Mesozoic exhumation history of the Grenvillian Oaxacan Complex,southern Mexico

We present the first fission‐track results from the Grenvillian Oaxacan Complex, southern Mexico. Time–temperature modelling of the data indicates that two significant Mesozoic cooling episodes are recorded in the Oaxacan Complex and these are interpreted as resulting from exhumation. The older cooling event took place from the Late Triassic to Middle Jurassic and is possible linked to the break‐up of Pangea (including the initial opening of the Gulf of Mexico during the Jurassic). The younger exhumation period in the Early Cretaceous is contemporaneous with the final stages of rifting of the Gulf of Mexico. Key stratigraphic records also provide independent evidence for these exhumation episodes. In our view, both Mesozoic rapid exhumation events were controlled by the activity of the Caltepec Fault Zone and the Oaxaca Fault. Our data suggest that both these large fault systems have remained active since, at least, the Late Triassic.     

Assessment of annual high‐water events for the Mackenzie River basin,Canada

River ice break‐up is known to have important morphological, ecological and socio‐economic effects on cold‐regions river environments. One of the most persistent effects of the spring break‐up period is the occurrence of high‐water events. A return‐period assessment of maximum annual nominal water depths occurring during the spring break‐up and open‐water season at 28 Water Survey of Canada hydrometric sites over the 1913–2002 time period in the Mackenzie River basin is presented. For the return periods assessed, 13 (14) stations are dominated by peak events occurring during the spring break‐up (open‐water) season. One location is determined to have a mixed signal. A regime classification is proposed to separate ice‐ and open‐water dominated systems. As part of the regime classification procedure, specific characteristics of return‐period patterns including alignment, and difference between the 2 and 10‐year events are used to identify regime types. A dimensionless stage‐discharge plot allows for a contrast of the relative magnitudes of flows required to generate maximum nominal water‐depth events in the different regimes. At sites where discharge during the spring break‐up is approximately one‐quarter or greater than the magnitude of the peak annual discharge, nominal water depths can be expected to exceed those occurring during the peak annual discharge event. Several physical factors (location, basin area, stream order, gradient, river orientation, and climate) are considered to explain the differing regimes and discussed relative to the major sub‐regions of the MRB. Copyright © 2008 John Wiley & Sons, Ltd and Her Majesty the Queen in right of Canada.     

A Modelling Study of Flux Imbalance and the Influence of Entrainment in the Convective Boundary Layer

It is frequently observed in field experiments that the eddy covariance heat fluxes are systematically underestimated as compared to the available energy. The flux imbalance problem is investigated using the NCAR’s large-eddy simulation (LES) model imbedded with an online scheme to calculate Reynolds-averaged fluxes. A top–down and a bottom–up tracer are implemented into the LES model to quantify the influence of entrainment and bottom–up diffusion processes on flux imbalance. The results show that the flux imbalance follows a set of universal functions that capture the exponential decreasing dependence on u _*/w _*, where u _* and w _* are friction velocity and the convective velocity scale, respectively, and an elliptic relationship to z/z _i , where z _i is the mixing-layer height. The source location in the boundary layer is an important factor controlling the imbalance magnitude and its horizontal and vertical distributions. The flux imbalance of heat and the bottom–up tracer is tightly related to turbulent coherent structures, whereas for the top–down diffusion, such relations are weak to nonexistent. Our results are broadly consistent with previous studies on the flux imbalance problem, suggesting that the published results are robust and are not artefacts of numerical schemes.     

云南安楚高速公路大红田隧道涌水分析

依据大红田隧道水文地质勘察和监测数据,结合前人已有成果,重点探讨隧道涌水特征、涌水影响范围及地下水消失量,并尝试对断流泉出流进行预测。     

广西十万大山盆地构造特征新认识

 通过对横穿十万大山前陆盆地的SD94-Ⅳ地震剖面的解释,证实十万大山盆地曾经历了至少2次以上的不同方向的构造运动:早期为前泥盆纪,表现为北西向南东的冲断;晚期为中泥盆世至白垩纪,构造由南东向北西发展.该地区在加里东期存在的北西向南东方向的构造运动值得进一步研究.     

新月形沙丘迎风坡气流加速模拟

迎风坡气流加速是决定新月形沙丘发育和形态的动力因子，研究这一加速过程的定量关系有利于认识沙丘的发育、沙丘的形态、沙丘的运动等。通过大量的野外实测数据和前人的理论分析，得出沙丘迎风坡气流加速量主要和沙丘坡度、迎风坡前来流风速以及沙丘高度有关，并建立了新月形沙丘迎风坡气流加速和沙丘形态特征的定量关系。根据这一关系得了在风力较强的风沙环境中，沙丘坡度较小；在风力较弱的风沙环境中，沙丘坡度较陡。地表粗糙度越大，迎风坡坡度越陡。沙丘地貌发育高度存在一上限，这一上限与边界层厚度有关。     

宝钢原料堆场采用砂桩加固软弱地基与分级堆料提高地基强度的实施效果

场地在工程地质分区上属于软土地层区、天然地基不能满足原料堆场的强度要求。为保证原料场的稳定与安全,在地基的处理上,采用了挤密砂桩和利用生产原料的自重进行分级堆高预压两项加固措施,增大了地基强度,达到了设计要求。     

实现栅格图形和图像数据矢量化提取的游程轮廓追踪法

提出一种直接利用栅格图形游程编码进行图斑边界多边形矢量化提取的有效方法。对遥感图像专题信息和栅格型地理空间分析结果的矢量化提取是GIS的重要手段 ,栅格数据结构可简化解决叠置分析等一类空间分析问题 ,其中需要高效矢量化技术的支撑。本方法充分利用栅格游程编码所具有的可操作性强、检索和转换便捷、隐含横向差异信息、可处理高精度和大规格图形和图像等特征 ,定义了“上邻游程”和“下邻游程” ,并采用相应有效查找算法和基于游程轮廓追踪的矢量化技术 ,使得计算机处理栅格数据矢量化的规模、精度和效率明显提高 ,可广泛应用于栅格型地理空间分析和遥感图像处理等方面。