结合南水北调东线工程实现京杭运河(济宁-天津段)复航

探讨南水北调东线工程与京杭运河航运协调发展的可行性和必要性,分析航运用水、复航条件、通航期等问题,并在此基础上提出了分阶段逐步恢复京杭运河(济宁以北至天津)通航的规划方案,力争早日实现交通部提出的“三横一纵”中“一纵”目标,使之成为我国重要的南北向水路运输大通道。     

Ni-S电极的制备方法研究

本文探讨了Ni-S电极的制备方法,通过改变电镀时间、电流密度和硫代硫酸钠的浓度,得出Ni-S电极制备的最佳工艺条件。     

雪峰山隧道涌水规律与特征分析

隧道建设过程中往往会遇到涌水的情况,给施工带来困难和不安全因素。文章通过对雪峰山隧道施工过程中洞内涌水的长期观测,总结出隧道施工涌水的一些规律和特征,为今后类似隧道的施工涌水的预测和防治提供参考。     

敞开式TBM空推步进技术在引松供水工程的应用

引松供水工程4标段隧洞主要采用敞开式TBM进行施工，为节省工期，部分洞段变更为钻爆法施工接应，TBM步进通过。为使TBM在圆形钻爆段快速步进，通过分析TBM在圆形断面空推步进的影响因素，研究钻爆段弧形底板的施工方法、质量控制措施，以及TBM在步进过程出现撑靴撑不到洞壁、撑碎洞壁，底板破碎和底部高低不平等问题的解决措施，使TBM安全、快速步进通过；通过与滑板式步进技术进行对比分析，总结2种步进方式的适应性以及优缺点。     

Effect of freeboard and metacentric height on capsizing probability of purse seiners in irregular beam seas

The probability of capsize of purse seiners in irregular beam seas and the effect of freeboard height and metacentric height on trapped water on the deck was investigated. The aim was to quantify a safety level that can be achieved by direct stability assessment for this type of fishing vessel. The amount of trapped water on deck was numerically estimated using a hydraulic flow assumption. The long-term capsizing probabilities were estimated using a piecewise linear approach together with wave statistics from major Japanese fishing areas. The estimated safety level of capsizing probability was compared with that obtained by the IMO weather criterion and by the water-on-deck criterion of the IMO Torremolinos Convention. Numerical results for four typical Japanese purse seiners indicated that the effect of freeboard, on the amount of trapped water on deck, is more important than that of the metacentric height. Besides the metacentric height and the freeboard, it was shown that the danger of capsizing is a function of the rise of floor. The safety level obtained by the capsizing probability approach is generally higher than that based on the IMO weather criterion. However, the water-on-deck criterion provides a higher safety level than the capsizing probability approach for ships with a low rise of floor.     

洋山深水港区二期工程简介及与一期工程之异同

上海国际航运中心二期工程是在总结一期工程设计施工经验的基础上,依据二期工程所处小洋山本岛前沿陆域纵深相对较小,港区陆域欠规正,成陆地基有山体基岩和深层淤泥等复杂条件,遵照“归顺水流,减少淤积,安全靠泊”的原则及与一期工程可合并经营、统一管理,也可分开管理、独立经营的原则进行港区布置。实现了同一期码头前沿一致的-16m水深,加长了泊位长度,优化了设备选型,提高了泊位通过能力。同一期工程比较,用每个泊位相对较低的投入取得了更高的吞吐能力与经济效益。     

水矢量技术在冷却塔的工业应用分析

冷却塔的作用是将携带的冷却水在冷却塔内与空气进行热湿交换,空气带着冷却水的废热送入大气散发,使冷却水水温下降,将宝贵的水资源循环利用。传统冷却塔主要依靠电力来驱动风扇,产生大量的电费,而这部分费用在企业成本支出中比例占比较大,给企业造成了很大的压力。文章所阐述的水矢量技术是一种新型的科研技术,其在冷却塔上的工业应用,刷新了传统式的冷却行业模式。对于业界冷却塔的设计应用具有很好的参考意义。     

渝怀线武隆隧道岩溶涌水量计算新方法

以三重空隙介质理论和化学动力学水文地质理论为基础,根据武隆隧道的岩溶水文地质条件,将岩溶含水介质空隙分为三种基本类型,提出折算渗透系数KL的概念,并根据变通后的达西公式将三种空隙介质中存在的不同流态耦合于达西—非达西流控制方程,提出一种新的岩溶隧道涌水量计算方法。利用该方法进行隧道岩溶涌水量计算主要有两大优点:一是可进行分段隧道岩溶涌水量计算;二是计算中最关键的参数折算渗透系数KL容易获取。     

Nutrient status of the Northeast Water Polynya

The nutrient distribution in the Northeast Water Polynya (NEW) was investigated intensively between the end of May and the beginning of August 1993 during the R/V Polarstern cruise ARK IX. The major characteristics were low initial nitrate concentrations (ca. 4 μM) in the surface mixed layer of the East Greenland Shelf Water, accompanied by high silicate values (ca. 10–14 μM). These concentrations were not reduced by phytoplankton growth. Silicate was rather homogeneously distributed in the entire water column, whereas nitrate increased continuously with depth to about 13 μM. Phosphate concentrations were about 1.1 μM and had a similar distribution to that of silicate. During the course of the summer, nutrients became depleted, and nitrate was exhausted in large parts of the NEW. Silicate was reduced to values of less than 2 μM at some stations which implies that diatom growth continued despite nitrate depletion, ammonium serving as a nitrogen source. The polynya is fertilised by water with the initial nutrient concentrations downstream of the Norske Øer Ice Shelf. This process continuously supplies nutrients to the surface throughout the year and these are transported northward by the anticyclonic surface circulation following the topography of the trough system. The northern boundary of this tongue of relatively nutrient-rich water is controlled by the uptake of nutrients by phytoplankton in summer. Its extemsion is variable due to interactions between biological processes, circulation and ice cover. In the Ob Bank region the nutrient distribution can be altered by the inflow of Polar Water from the north when strong northerly winds prevail as happened during the first part of the study.     

Numerical determination of flushing time for stratified water bodies

It is often advantageous to model a semi-enclosed estuarine or coastal embayment (e.g. fish farms or tidal inlets, or typhoon shelters) as a separate system within a larger water body connected to the outer sea. The water quality of the system depends crucially on its flushing time—the average time of a particle in the system. The flushing time is governed by the barotropic and baroclinic tidal exchanges between the system and the outer sea. We describe herein a general method to determine systematically the flushing time of a stratified water body via a numerical tracer experiment. Numerical solution of the 3D flow and mass transport equations for many practical problems show that the tracer mass removal process depends on the physical topography and bathymetry, tidal range and the degree of stratification in the outer sea. Field application suggests that the tracer mass variation can be well approximated by a double-exponential decay curve that can be described by three flushing coefficients. Using a simple analytical two-segment model, the flushing coefficients can be given a clear physical interpretation, and the flushing time can be easily determined in terms of the coefficients. The method is illustrated by application to a number of tidal inlets in Hong Kong, in both the dry and wet season. The connection between the numerically determined flushing time and the traditional bulk flushing time obtained from salt-balance methods is established.