水温分层型水库铁、锰垂直分布特征

贵阳市主要饮用水源地阿哈水库系水温分层型季节性缺氧水库,由于沉积物含高浓度Ｆｅ,Ｍｎ至使库水受到污染,经多年测定不同季节２０ｍ深垂直水柱结果表明,Ｆｅ,Ｍｎ分布随着季节变化,水库水温分层而变化,呈现明显的垂直分布规律,高浓度Ｆｅ,Ｍｎ主要出现在水温分层期水库中,下层,与库底缺氧,ＰＨ下降沉积物浓度Ｆｅ,Ｍｎ释放造成的二次污染等密切相关,从而为自来水厂实施优化分层取水和污染控制提供了依据。     

我国现代化海洋牧场智能运维的发展现状与建议

文章将介绍现代化海洋牧场及其智能运维的概念,结合实例说明海洋牧场智能运维的装备和技术现状以及发展中存在的问题,并在最后提出推动海洋牧场智能运维进一步发展的建议：落实政策倾斜,建立基础设施;扩大产业规模,促进资源共享;发展交叉学科,重视自主研发;优化渔业结构,实现精细运维。     

中长周期波作用下的斜坡堤胸墙波浪力试验研究

在印度洋、大西洋沿岸,海岸工程设计波浪周期多在14 s以上,具有显著的中长周期波特征。通过以往工程项目的试验结果发现中长周期波下,规范计算的斜坡堤胸墙波浪力明显小于试验结果。因此,通过系列物理模型试验研究了中长周期波下的斜坡堤胸墙波浪力。分析斜坡坡度、肩台宽度和波浪条件对胸墙波浪力的影响。通过将试验结果与我国现有规范中的经验公式计算所得结果进行对比,发现规范更适用于胸墙底淹没的情况,而对于肩台出水情况,规范计算结果小于试验结果。由此提出了一种新的波浪力计算方法,计算准确度得到明显提高。     

IGSվ�ļ��νṹ��������GPS�����������ܹ��ȷ����Ӱ�����

????2008???????87??95????????ν?????????IGS????????????????GPS??????????????????????????????IGS?????????????????????????????y???????40??IGS????????????GPS??????????????????????????侫???????4.9??3.6??3.4 cm????IGS?????????????GPS??????????????????????????????????????????????????????????????????IGS??????????IGS?????ν????????????????????     

关于地理信息产业的发展及几点建议

进入信息时代 ,地理信息产业迅速发展 ,取得巨大的成果 ,现代化的地理信息产品和技术服务在经济与社会可持续发展中的重要作用越来越明显 ,因此发展地理信息产业自然成为更为重要的任务     

计算机缩放图功能的开发和应用

本文介绍了采用计算机数字化仪的点输入功能,将曲线数字化。通过程序处理,对原图进行缩放,绘制任意比例尺的图件。其特点是操作简便、工作效率高,能满足绘图精度要求。     

G298 – A New Candidate γ Doradus Star in the Direction of the Globular Cluster M4

G298 = L3216 (V = 12.68, B?V = 0.59) is a field star in the direction of the globular cluster M4. It was used as one of our comparison stars in the past, now it is shown that G298 is a new γ Dor variable star with a period of 1.03099 day and peak to peak amplitude of about 0.02 mag in V. Its spectral type is F2 (IV ?).     

木星“大红斑”的旋转浅水实验模拟研究

在具有自由表面的旋转轨物面浅水实验系统上进行了可重复的系列模拟实验，在旋转随动坐标系中拍摄的照片和功率谱分析表明，确有大尺度持续存在的涡旋、漂移与演化产生，在一定条件下，呈现出一个自持的、长寿命的、沿与整体旋转方向相反方向漂移的反气旋孤立波涡旋（Rossby孤立波涡旋），这就是木星“大红斑”的实验室模型，实验结果证实，流体动力学不稳定主要来自于剪切和Coriolis力效应，由于远离平衡态的耗散系统的自组织，涌现出大尺度长寿命相干涡旋结构，受多次实验的启发，从流体动力学基本方程出发，在一定的实验条件下提出一个半经验模型，近似求出了Rossby孤立波涡旋解。     

Bivariate frequency analysis: discussion of some useful concepts in hydrological application

Basic concepts such as conditional probability distributions, conditional return periods, and joint return periods are important to understand and to interpret multivariate hydrological events such as floods and storms. However, these concepts are not well documented in the open literature. This paper assembles and clarifies these concepts, and illustrates their practical utility. Relationships between joint return periods and univariate return periods are also derived. These concepts and relationships are demonstrated by applying a bivariate extreme value distribution to represent the joint distribution of flood peak and volume from an actual basin. Copyright © 2002 John Wiley & Sons, Ltd.     

Experimental study on the effectiveness of TLDs under wave loading

The objective of this study is to experimentally investigate the effectiveness of Tuned Liquid Dampers (TLDs) for suppressing the dynamic response of a platform structure subjected to wave loading and to explore the applicability of TLDs for suppressing the structural vibration of fixed offshore platforms. The experimental model is scaled according to a full size platform by matching its dynamic properties. Rectangular and circular TLDs of various sizes and water depths are examined.The experiments were performed in a 2-D wave flume. The effectiveness of TLDs is evaluated based on their response reduction. By observing the performance and the behavior of TLDs through laboratory experiments, the effects of a number of parameters including container shape, container size, number of dampers, frequency ratio, mass ratio, and incident wave characteristics are investigated.