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业主方的项目管理是水利工程建设项目管理的核心.文中重点探讨了水利工程业主方在整个项目周期各阶段的管理目标和管理内容,以及水利工程业主方项目管理存在的问题及对策. 相似文献
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红壤坡地不同生态措施地下径流养分流失研究 总被引:4,自引:0,他引:4
利用大型土壤渗漏装置(Drainage Lysimeter)对百喜草覆盖、百喜草敷盖、裸露三种生态措施的地下径流养分流失问题进行了研究.结果表明:在试验期间这三种处理措施氨氮流失总量分别为992.64 mg,2 679.67 mg,258.84 mg;总氮流失总量为1 096.494 mg,3 108.376 mg,295.064 8 mg;总磷流失量为603.35 mg,3 109.45 mg,182.42 mg;养分随地下径流流失量敷盖最大、裸露对照最小,这和一般情况下地表径流养分流失有所不同;从流失过程可以看出这三个处理的地下径流养分流失和径流过程比较相似,符合"肥随水走"的水肥运动规律,当降雨过后地下径流变大,养分流失也增大;在整个过程中,氨氮随径流过程变化剧烈,而且随地下径流流失量大,总磷则相对平稳,而且流失量也小. 相似文献
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郭家寨水库冲滩造槽排沙试验 总被引:2,自引:0,他引:2
郭家寨水库投入运行34年,泥沙淤积严重,淤积总量达52.9万m ̄3,占总库容99万m ̄3的53.4%,坝前淤积面仅比溢洪道底坎低0.1m,排沙泄洪洞前泥沙淤积厚度8.5m,库区淤积滩面纵比降2.1‰,据历次实测的库容曲线对比;泥沙淤积死库容占98.8%,淤损兴利库容33.1%,减少22.2%的防洪库容,水库基本丧失了兴利库容的调节能力,减少灌溉面积2300余亩。1978年前采用“蓄洪排清”运用方式,1979~1993年改用“空库渡汛”方式均不能减缓水库泥沙淤积速度。现选用水力挖塘机组辅助式的高渠拉沙方法,效果较佳。10天排沙4.93万m ̄3,死库容复活9.3%,淤滩造地50余亩,出库泥沙利用60%以上,单机日排沙1020m ̄3,排沙耗水率1.76,排1m ̄3沙耗资0.25元,比基流冲刷排沙相比,日排沙量高2倍,排沙耗水只占1/11,耗资为1/4。 相似文献
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测井曲线拐点在测井层序地层分析中的应用研究 总被引:4,自引:3,他引:1
在层序地层学研究中,层序界面的划分是基础和重要的环节,而利用测井资料分析可以进行层序界面划分和进行较长期基准面旋回识别。测井曲线的值是深度的函数,测井曲线的一阶导数表示了曲线变化的趋势和变化的快慢,在某一范围内,当一阶导数呈现符号转换时,相对应的深度点的测井值即为该范围内极大(极小)值;测井曲线的二阶导数则表示曲线的凹凸性,在某一范围内,当二阶导数呈现符号转换时,相对应的深度点代表了测井曲线的拐点,即反映曲线凹凸性变化的转折点,亦即地层的分界面。基于以上特点,提出利用测井曲线拐点进行层序界面划分的原理和方法,并结合岩心和录井资料,对白音查干凹陷达28井腾格尔组不同级次沉积旋回、地层垒积、旋回特征随沉积厚度变化特点和不同级次基准面旋回进行研究,最后得到该地层单井测井层序地层分析结果。 相似文献
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提出了对铁路用承力索电连接线夹的加工采用:熔铸、挤压、拉伸工艺。从生产实际角度介绍了电连接线夹生产过程中的工艺参数选择、控制以及采取的相关措施;并对产品缺陷及产生原因进行分析。为电连接线夹加工提供了很好的创举。 相似文献
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钛合金表面热喷涂NiCrAl涂层和热障涂层的氧化性能 总被引:1,自引:0,他引:1
采用超音速等离子喷涂技术在TC4和Ti40钛合金表面制备NiCrAl及NiCrAl+ZrO2热障涂层,测定TC4、TC4+NiCrAl、TC4+NiCrAl+ZrO2、Ti40、Ti40+NiCrAl、Ti40+NiCrAl+ZrO2在600℃下的氧化动力曲线。通过扫描电镜(SEM)和能谱(EDS)分析研究钛合金、NiCrAl涂层和热障涂层组织形貌。结果表明:TC4在600℃的抗氧化性能优于Ti40;NiCrAl涂层与热障涂层能明显提高TC4和Ti40在600℃下的抗氧化性;600℃下氧化100h后,NiCrAl涂层、NiCrAl+ZrO2涂层与TC4界面处出现了扩散带和锯齿状的相,而与Ti40界面处只出现了扩散带,未发现锯齿状的相。 相似文献
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分析了超超临界1 000 MW机组锅炉无炉水循环泵(BCP)吹管蒸汽超温的原因,提出了在吹管过程中提高给水温度、降低锅炉燃料量和炉膛出口烟气温度,防止过热蒸汽带水等控制蒸汽温度的措施.实施后,可将蒸汽温度控制在锅炉吹管的要求范围内,实现了超超临界1 000 MW机组锅炉在无BCP条件下的顺利吹管. 相似文献
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Most of the world's cities are concentrated in coastal areas. As a special geo-graphical component of the coastal system, island urban spatial expansion is the outcome of interactions between city development and the physical environment. This paper takes Xia-men Island, located in Southeastern China, as an example to analyze island urban spatial expansion and its determinants by combining an analysis of the literature on urban devel-opment policies, urban overall plans, population growth and industrial development, with geographical information analysis using historical maps and remote sensing photographs.Firstly, we reviewed the history of the Xiamen City development during the last 100 years,which can be divided into four periods:the embryonic modern city and early development from 1908 to 1949; administrative boundary expansion and infrastructure development from 1950 to 1979; special economic zone construction and rapid urbanization from 1980 to 2003;and Bay City construction since 2003. The dynamic changes to the coastline, island shape,built-up area, transportation, administrative division, and major land use type conversion which occurred during approximately the past 100 years were analyzed and the characteris-tics of the island urban spatial expansion were concluded:early expansion from a central point, followed by expansion along a section of coastline, and expansion from the coastline inland. Secondly, we discussed the potential determinants of island urban spatial expansion including administrative division adjustment, urban master planning revision, industrial de-velopment, topographical factors, coastal area reclamation, transportation expansion, and population growth. Finally, the effects of each potential determinant on island urban spatial expansion were concluded. Island urban spatial expansion is the result of a synthesis of natural and socio-economic factors which are not independent but interacting. Built-up area expansion is the major driver of island land cover and land use changes. By this paper, we hope to provide a scientific reference contributing to the rational understanding of island and coastal sustainable urbanization in China, and the world beyond. 相似文献