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4DA1发动机气缸体螺栓孔渗漏的分析和解决
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作者 于娜红 周杰 《铸造》 CAS CSCD 北大核心 2008年第1期69-72,共4页
缩松缺陷是导致4DA1型发动机气缸体螺栓孔渗漏的主要原因。通过控制铁液成分、浇注温度、Cr加入量,选择合适的孕育剂,使用碲涂料等综合控制手段,能有效降低缩松缺陷,防止气缸体渗漏现象。
关键词 缩松 渗漏 碳当量 孕育剂 涂料
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Vertical changes of POC flux and indicators of early degradation of organic matter in the South China Sea 被引量:2
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作者 陈建芳 郑连福 +3 位作者 徐鲁强 郑士龙 M.G.Wiesner H.K.Wong 《Science China Earth Sciences》 SCIE EI CAS 1999年第2期120-128,共9页
Tie-series sediment trap materials at different water depths and surface sediments in northern and central South China Sea (SCS) were analyzed for organic carbon, amino acids, amino sugars and carbohydrates. Results s... Tie-series sediment trap materials at different water depths and surface sediments in northern and central South China Sea (SCS) were analyzed for organic carbon, amino acids, amino sugars and carbohydrates. Results show that particulate organic carbon (POC) is mainly derived from marine plankton, only 1.4%–1.6% of primary production sinks into deep SCS water column and less than 0.22 % of primary production ultimately reaches the sediments. The ranineralization and dissolution of organic matter as well as the compositional alterations of organic matter mixtures may mainly take place in the upper few hundred meters of water column, deep carbonate (opal) lysocline zones, and interface layers between sediments and water column, rather than in mid-waters. The organic geochemical parameters such as (T aa +T sug )OC%, AA/AS, Gluam/Galam, Arom. AA/non-prot. AA, ASP/b-ALA, Glu/g-ABA decrease from living marine plankton (or planktonic shells), to settling particulate matter and to sediments suggesting that they appear to be gad early degraded indicators of organic matter. 展开更多
关键词 South China Sea (SCS) particulate organic csrbon (POC) amino acids amino sugars carbohydrates vertical changes early degradation
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