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<正>材料发生腐蚀是一种自发现象,然而近年来随着人类的发展,各种环境下腐蚀对人类生产和生活造成的损失越来越严重。统计资料显示,我国目前由于腐蚀受到的经济损失每年在3 000多亿元,因此无论从社会效益还是从经济效益考虑,都要把腐蚀造  相似文献   
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用失重法、动电位极化测试考察不同质量浓度、温度下,壳聚糖在lmol/LHCl溶液中对碳钢的缓蚀作用及机理。结果表明:随缓蚀剂质量浓度增加,壳聚糖的缓蚀效率升高,腐蚀速率下降;温度升高,腐蚀速率加快,但缓蚀效率并未下降,333K时缓蚀效率仍可达93.8%;壳聚糖在金属表面的吸附行为符合Langmuir吸附等温线,其与金属...  相似文献   
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Organic matter in cobalt-rich crust(CRC) from the Marcus–Wake Seamounts of the western Pacific Ocean, Sample CM1D03, has been analyzed to understand the source, geochemistry and mineralization of organic matter, and the mineralization environment. Biomarkers, including n-alkanes, isoprenoids, terpanes and sterols, have been detected in various layers of the CRC sample, using gas chromatography(GC) and gas chromatography–mass spectrometry(GC–MS). The content of organic carbon(OC) and its stable isotope(δ13C), and the combined features of the biomarkers show that the mineralized organic matter in CM1D03 CRC was mainly derived from microorganisms and lower plankton(e.g., bacteria and algae, respectively) from marine surface water, with some terrestrial higher plant components. The ratio of chloroform bitumen "A": OC was high in the CRC, between 10.51 and 20.66, showing significant migration characteristics of n-alkanes. Four mineralization categories of organic matter were recognized based on GC chromatograms of n-alkane molecules:(1) primitive type(bacteria and algae), which is characterized by moderately mature of n-alkanes preserving the original characteristics of the organic matter from microorganisms and lower plankton;(2) microbial degradation type, which is characterized by low contents of n-alkanes and rising baseline in the chromatogram, with the "bulge" being the products of organic matter by biodegradation;(3) organic matter migration type, which is characterized by low carbon number of n-alkanes with n C18 as the main peak carbon, without odd even predominance, and low concentrations of isoprenoids and hydrocarbons with high carbon number; and(4) organic matter hydrothermal type, which is characterized by relatively low concentration of small molecular weight n-alkanes, pristane, and phytane, accompanied by higher concentration of n-alkanes with carbon number greater than n C18. This study shows that biomarkers can record controlling factors of mineralization and their variation.  相似文献   
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文章综述了国内外有关海洋中营养盐陆源补充机制及其对浮游藻群落结构影响的研究动态,研究表明人类活动极大地改变了海洋营养盐的浓度和组成,并导致近海浮游生态系统发生了一定的变化,主要表现为:海域富营养化加剧,非硅藻类赤潮爆发次数明显增加.然而,筑坝对海洋环境的影响研究仍存在许多问题,有待进一步研究.  相似文献   
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文章综述了国内外有关底泥耗氧的研究动态。对比实验与现场观测两种方式:现场培养只能提供底泥耗氧总量,但该数值不能获得除此之外的更多信息,如影响氧气生产或消耗的生物化学过程,沉积物中氧气的分布以及间隙水氧气动态变化;而实验室培养过程能够作为前者的补充。在现场模拟实验,其结果被认为更接近于实际,但系统环境条件人为调节困难。室内与现场观测的结果虽有少量差别,但室内实验易于控制,因此,大多数研究者选择在室内进行实验。  相似文献   
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