已建储罐底板的阴极保护系统

针对大型储罐施加阴极保护后,如何使电流分布均匀,如何测量保护电位等问题,介绍了国外大型储罐安装的斜井阳极阴极保护系统。该系统采用钻孔的PVC塑料管可以方便地测量储罐对地电位,与均布在储罐周围的阳极地床以及深井阳极地床相比,斜井阳极电流分布更为均匀,且能更好地保护罐中心底板。     

Seismic Behaviour of Multi Story Brick Building with Frame Shear Wall in the Two Botton Floors

A shear vibrational model applied assemblage of multiple particles is proposed for the seismic response analysis of masonry building with R/C frame wall in the two bottom floors.On the basis of analyses,some problems are discussed,these mainly are:dynamic properties,main factors that have influence on seismic behavior,earthquake resistant reliability of this building under strong earthquake and the rational ratios of lateral rigidity.[WT5HZ]     

浮顶油罐底板修理

大型浮顶油罐在经过长期运行后,罐底板出现严重腐蚀、穿孔,焊缝出现裂纹和剥层,严重影响油罐正常运行。以５座油罐大修为例,提出了大修施工中方案的选择和实施应考虑的因素,一是大修前采用多种方法检测腐蚀,根据揭示的腐蚀种类和程度确定修理方案;于是针对不同腐蚀状况,选用堆焊磨平、局部换板、全部换板及相互结合的方法。详细介绍了５座油罐的检测与修理过程,并提出了罐底板在修理过程中应注意的事项。     

RAPD技术鉴定3种鲮的研究

以池塘养殖的鲮、麦鲮各１２尾为材料,提取血液基因组ＤＮＡ,利用１０ｂｐ随机引物进行ＰＣＲ扩增,通过缩短扩增反映时间和电泳时间,快速鉴定３种不同的鲮值,建立了一套ＤＮＡ分子水平上的快速鉴定鱼种的方法。     

千岛湖底泥重金属污染的生态风险评价

水体底泥污染是世界范围内的一个环境问题,污染物通过大气沉降、废水排放、雨水淋溶与冲刷等途径进入水体,最后沉积到底泥中并逐渐富集,使底泥受到污染。千岛湖不同监测点底泥Cu、Zn、M n、Pb、Cd、A s、Hg等重金属含量存在差异。大坝前、毛竹源和三潭岛监测点M n、A s和Hg含量较高。不同采样点,底泥重金属污染度有差异,表现为毛竹源>三潭岛>航头岛>茅头尖>大坝前>排岭水厂>街口,毛竹源测点底泥重金属污染风险最高,街口重金属污染风险最低。     

用电位分布数学模型评价罐底阴极保护效果

地面金属储罐底极阴极保护技术中关键问题之一是判断罐底,特别是罐底中心的保护效果,目前缺少经济和简便的测量罐底保护电位的方法,电位分布数学模型为研究罐底保护提供了一种解决途径。根据稳流电场理论推导并试验验证了罐底阴极保护电位分布的数学模型,发现罐底保护电位和距罐底中心比率距离成类似立方抛物线方程形式。根据这个模型讨论罐底电位分布规律,提出罐周电位检测及一点法、二点法、多点法等电位检测技术用于评价阳极     

钢筋混凝土钻孔灌注桩施工质量探析

了解并掌握钻孔灌注桩的施工工艺流程,抓住影响其质量的关键环节和关键因素,并采取有效的控制措施,可提高和保证钻孔灌注桩的成桩质量。     

Linking spatial pattern of bottom fish assemblages with water masses in the North Sea

Understanding the links between large scale spatial structuring of fish assemblages and shaping factors is essential to develop comprehensive ecosystem-based fisheries management. In this study, we investigated spatial patterns of bottom fish assemblages in the North Sea in relation to prevailing water masses in the region. We based our analysis on catch data from the German Small-Scale Bottom Trawl Survey conducted between 1987 and 2005 and used both ordination techniques and Mantel tests. Spatial variability of bottom fish assemblages was larger than inter-annual variability. Five significantly different bottom fish assemblages were associated with the following prevailing hydrographical regimes: i) the English Channel, ii) Continental Coastal, iii) central North Sea, iv) northern North Sea, and v) northern Atlantic water masses. Associations were generated by gradients in relative proportions of abundant species such as grey gurnard ( Eutrigla gurnardus ), dab ( Limanda limanda ), whiting ( Merlangius merlangus ), haddock ( Melanogrammus aeglefinus ) and Norway pout ( Trisopterus esmarki ). Taking into account large scale spatial structuring of catch data Mantel tests confirmed significant correlation between the fish assemblages and hydrographical variables. In summary, our results strongly support the hypotheses that hydrographical features such as water masses, fronts, and residual currents could shape bottom fish associations in the North Sea. Spatial demarcations of bottom fish assemblages indicated by this study can be used to support ecosystem-based fisheries management strategies.     

渤海底拖网主要渔业生物类别时空分布的初步研究

为研究目前渤海主要渔业生物的时空关系,文章依据2014年~2015年渤海双船底拖网4个季度调查数据,初步分析了渤海三类主要渔获物(鱼类、甲壳类和头足类)的水平空间分布特点、空间距离及四季变化特征。结果显示,三类生物的主要分布区水平方向上存在空间分化现象,且随着三类生物集中分布区聚集程度的提高,空间分化现象越来越明显。三类生物的水平空间分布距离在季节上表现出夏、秋季(平均欧氏距离,夏季为75.91;秋季为44.76)较远,冬、春季(冬季为8.55;春季为11.81)较近的特点。三类生物间,头足类与甲壳类的距离相对较近(平均欧氏距离,24.44),而头足类与鱼类(40.07)、鱼类与甲壳类(38.27)的距离相对较远。