膨润土膨胀变形与膨胀力试验研究

膨润土被选为高放废物深层地质处置库的缓冲/回填材料,有必要研究其力学性能。使用固结仪对不同干密度和含水率的钙基膨润土进行了膨胀变形与膨胀力的试验研究。试验结果表明：膨润土的膨胀应变主要取决于膨润土的初始干密度和含水率,随着初始干密度的增加而增加,随初始含水率的增加膨胀变形逐渐减小。     

针刺法膨润土复合防水衬垫的结构与力学性能研究

为研究膨润土复合防水衬垫(GCL)的组成和结构对其力学性能的影响,观察膨润土表面形态结构以及对膨润土复合防水衬垫的拉伸强度和剥离强度进行试验研究。结果表明:膨润土遇水后表面结构发生改变,从而使其抗渗性能增强;复合防水衬垫的拉伸性能主要由编织土工布提供,拉伸强度为882.38N/10cm,剥离强度随剥离方向不同而异,剥离强度小于100N/10cm,拉伸强度要远大于剥离强度;水化前的膨润土对力学性能无影响;水化后的GCL纵向强度提高21.2%,横向强度提高11.8%,说明水化作用对力学性能有影响。     

纳米层状硅酸盐改性沥青相容性试验研究

在分析改性沥青相容性和配伍性的基础上,通过试验对比分析了膨润土MMT、1831-OMMT、31441-OMMT、松香基-OMMT纳米层状硅酸盐改性沥青、SBS改性沥青和PE改性沥青的相容性。结果表明,松香基-OMMT纳米层状硅酸盐改性沥青比SBS改性沥青具有更好的相容性。     

Summer hypoxia adjacent to the Changjiang Estuary

Changjiang, the third largest runoff in the world, empties into the East China Sea from Shanghai, the fastest developing area of China. With the increasing nutrient load from the river, a severe hypoxia zone was found to about 2  10⁴ km². The mechanism of hypoxia formation adjacent to the Changjiang Estuary receives more and more attention from both scientists and managers. This paper discusses the relationship between hypoxia and the water masses, primary production, particulate material transport and the density stratification in these areas according to data obtained from a cruise in September, 2003. Hypoxia is formed by organic detritus decay. The particulate organisms do not mainly come from the Changjiang river, or from the dead algal deposed locally, but from the local benthic algae or particles advected from the south. Maintenance of hypoxia is due to the large density stratification caused by the significant salinity difference between the fresh plume and salty water from Taiwan Strait. This applies also to other estuaries with large runoff and rapid economic growth drainage, such as the Pearl River. It is suggested that the hypoxic zone here is much more sensitive than that outside Mississippi River. More cruises over different weather and tide conditions are needed to prove this hypothesis. Interdisciplinary research should be further developed in the future.     

黄土盾构隧道膨润土泥浆渣土改良技术研究

为了解决黄土地层中土压平衡盾构施工地铁区间隧道时出现的出土困难、土仓压力难以建立以及刀具温度过高等问题,采用膨润土、泡沫对渣土进行改良才能保证盾构掘进效果。采用正交试验法进行了膨润土泥浆优化试验与泡沫优化试验。通过膨润土泥浆优化试验找到了适合黄土地层的膨润土改良剂及膨润土泥浆的最优体积分数。通过泡沫优化试验找到了泡沫性能与发泡剂溶液最佳体积分数的关系,本文研究成果在实际工程中得到了成功应用,以期为类似工程提供借鉴与参考。     

Variations in ectoenzymatic hydrolytic activity in an oligotrophic environment (Southern Tyrrhenian Sea, W Mediterranean)

The variations in the expression of two hydrolytic ectoenzymes (leucine aminopeptidase – LA – and β glucosidase — BG) were studied in the southern Tyrrhenian Sea during spring 2004. This area is characterised by a complex morphology and hydrodynamism, which generate significant differences between different sectors, particularly in the 0–100 m layer. However, the area generally exhibits oligotrophic features such as low autotrophic pigment and organic matter concentrations and a higher bacterial biomass than the phytoplanktonic one. Despite this general bottom-up pressure, adaptations by the microbial consumers were indicated by the ectoenzymatic activities and by the relationships between the enzymes, their organic substrates and their producers (namely the bacteria). In particular, bacteria were able to exploit the inorganic N supply (nitrite + nitrate provided by irregular intrusions of intermediate waters) to escape the bottom-up limitation and produce enzymes such as BG devoted to the degradation of cellulose remnants and, therefore, also able to take advantage on this refractory organic matter. In the 200–800 m layer, where trophic limitation was strong due to the low values of potentially-labile organic matter (namely proteins), the peculiar hydrodynamism led to the formation of nepheloid layers rich in organic matter, which provided the bacteria with substrates and allowed the development of a significant correlation between LA activity and its own organic substrate. Furthermore, a reduction of the bottom-up pressure was also indicated by a higher mean bacteria cell size in the entire water column of the central and eastern sectors, and a significantly increased expression of BG related to the increase in the cell size.The ectoenzymatic activities, therefore, suggested that the southern Tyrrhenian Sea should be considered as a mosaic of subsystems, where the peculiar hydrological features stimulate bacterial adaptations and enhance the channelling of energy embedded in refractory materials into the food web.     

威悉河隧道掘进工程中泥浆的经济性再生处理

为了保证工作面的安全，并有效运输隧道掘进时挖出的土碴，采用膨润土支护液体，完成任务后的支护液体必须经过处理，分离出来的沙土可以在工地上得到再利用（作为隔音墙和填充料）。从土碴处理和再利用的角度对泥水分离设备进行优化，从而使资源得到了保护，由于膨润土和絮凝剂的消耗最小化，提高了隧道工程的经济性，并减小了对环境的污染。     

Corrosion characteristics of coated automotive parts subjected to field and proving ground tests

This project evaluated the corrosion damage over a five-year period of organic coated steels in automotive chassis parts during P/G and field tests using electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. EIS can provide both quantitative kinetic and mechanistic information about the performance of organic coating/metal systems. The difference in coating performance between the P/G and field test specimens was assessed in relation to the impedance parameters. In particular, it was found that the coating resistance and charge transfer resistance could be used to estimate the difference in corrosion damage between the P/G and field test specimens. The coating performance of the P/G and field test specimens was visually evaluated using SEM. The mechanism of corrosion occurring in the P/G test was similar to that taking place in the field test. The field test environment was about ten times as corrosive as the P/G environment in terms of the electrochemical impedance parameters and surface analysis.     

泥浆护壁在深海大直径砂桩检测中的应用

上海国际航运中心洋山深水海基采用大直径深海砂桩。砂桩钻孔检测为防止塌孔埋住钻具,采用泥浆护壁。文章介绍了海水制浆的制备原理、材料选择、泥浆护壁的作用以及个别塌孔的原因分析。结果表明,一阶段工程检测顺利,取得满意的效果,为下阶段检测工作取得经验。     

膨润土毯（板）质量及其对地下工程防水的影响

针对膨润土毯(板)在设计制造和施工中所存在的一些重大技术问题,详细介绍了膨润土毯(板)的特点及适用条件、施工要术等作了详细的论述,可为膨润土毯(板)的设计、施工及其相关标准、规范的制订提供相关依据。