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101.
浮顶油罐底板腐蚀原因分析 总被引:1,自引:0,他引:1
针对长岭炼油厂17号原油罐运行中的腐蚀穿孔问题,分析了该油罐罐底的腐蚀原因,分析结果表明,油品物化性质,焊接质量,施工质量,油罐低液位运行,钢板材质及缺陷等是造成油罐罐底上下表面腐蚀的原因。为解决这些问题提出几项具体的技术措施。 相似文献
102.
103.
介绍了入侵检测技术以及基于Agent的入侵检测技术的发展和研究现状,分析了当前入侵检测系统面临的主要问题和发展趋势,并对入侵检测系统的改进提出了建议。 相似文献
104.
采用将两块半无限长弹性地基梁搭接的力学模型,对座落在弹性地基上的油罐搭接中幅板在液压作用下的受力情况进行分析,得出的应力可用于对罐底应力腐蚀和疲劳应力腐蚀分析。由于Ⅱ型弹性地基梁和刚性地基梁耦合法考虑的是对罐边缘板较窄或边缘板与中幅板搭接的情况,因此油罐中幅板的应力分析方法是此两种分析方法的基础。 相似文献
105.
106.
随着internet的发展,信息安全越来越引起人们的注意.据计算机紧急响应小组(CERT)公布的从1988年到1999年攻击事件增长数据可以看出,从1988年到1999年短短十年里,攻击事件增长将近20倍,与攻击相应的结果就是经济的损失,据美国商业杂志《信息周刊》公布的一项调查报告称,黑客 相似文献
107.
The Burdekin Delta is a major irrigation area situated in the dry tropics of North Queensland. It is unique in that (i) it overlies shallow groundwater systems that serve as a major water supply for the irrigation of sugarcane, and (ii) it is adjacent to the world heritage listed Great Barrier Reef. Water management practices include large recharge pits and surface spreading of water to assist with replenishment of the groundwater. This has been useful in maintaining groundwater levels to help control seawater intrusion. This technique, however, can be costly and ineffective in unconfined aquifer systems, which are subjected to large amounts of groundwater pumping for irrigation. There are more than 1800 production bores currently used for irrigation in the Burdekin Delta and the large volumes of water extracted have at times lowered the regional water tables and made it difficult to control seawater intrusion. 相似文献
108.
在快速城市化过程中,人为侵入体大量混入绿地,改变了土壤的三相组成及孔隙特征,但其对城市绿地土壤的入渗影响仍不清楚。基于一维垂直土柱入渗模拟,以典型人为侵入体砖块和混凝土碎块为例,研究其对城市绿地土壤水分入渗的影响特征。结果表明:(1)人为侵入体的混入均会抑制城市绿地土壤水分下渗,导致其稳定入渗速率降低,累积入渗量、湿润锋距离和土壤体积含水量减小,深层土壤水分变化滞后。同一配比下,以混凝土碎块对土壤水分入渗的抑制作用更为明显(P0.1);(2)随着人为侵入体配比从10%增加到20%,土壤稳定入渗率、累积入渗量、湿润锋距离和土壤体积含水量仍持续减小或略有增加,但差异均不显著(P0.1),其对土壤水分下渗的抑制作用渐趋减弱。(3)不同类型人为侵入体及配比下,城市绿地土壤水分的入渗量随时间变化更加符合Kostiakov模型。研究结果可为未来海绵城市的高效建设提供科学依据。 相似文献
109.
A recently developed echo sounder with a global positioning system (GPS) receiver can display both the boat position and echo
gram. However, this information is displayed in different views. In this paper, we present a new digital three-dimensional
(3D) echo sounder system comprising a traditional analog echo sounder, GPS receiver, notebook personal computer (PC), and
a low-cost, compact, self-developed universal serial bus (USB)-based analog-to-digital (A/D) converter board. Multiple echo
views can simultaneously display various desired targets more clearly than the view in a traditional analog echo sounder.
The newly developed analysis software can precisely extract the information related to bottom depth, plants, and fish schools
from the echoes. By combining the acoustic and position data, the system can map both the fish and plant echoes on the 3D
sea bed generated from the extracted bottom depth. This system has been proved to be useful in observing the 3D and wide-area
distribution of both fishes and aquatic plants and in studying habitat parameters in aquatic ecosystems. A notebook PC equipped
with the self-developed USB-based A/D converter board is capable of transforming any traditional analog echo sounder into
a high-performance 3D digital echo sounder. 相似文献
110.
Takashi Shimizu Tsutomu Takagi Holger Korte Tomonori Hiraishi Katsutaro Yamamoto 《Fisheries Science》2007,73(3):489-499
ABSTRACT: The net-shape and loading analysis system (NaLA) was developed to determine fishing net configuration and load in a previous study. The system has since been applied to general gill nets and aquaculture nets, and its validity has been proven through model experiments in tanks. In this study, the system was applied to estimate the dynamic behavior of a bottom gill net for walleye pollock, to test the system's applicability of the system to gear operations in the field. To obtain in situ data, four bottom gill net operations were performed in February 2004 off the coast of Sawara, Hokkaido, Japan. During operations, vertical displacements of the bottom gill net's float and sinker lines were measured as representative values of gear behavior, and ocean current direction, and speed at the gear position were observed simultaneously. Then, bottom gill net behavior was simulated using NaLA, incorporating observed environmental conditions and gear specifications. The resulting calculated behavior was compared to measured behavior in terms of the relationship between net height and environmental or setting conditions. Agreement between the calculated and measured net behavior was found. Thus, it is believe that our NaLA calculation model has the potential to simulate the dynamic behavior of bottom gill nets in situ . 相似文献