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141.
142.
冻融循环作用下富平黄土微观结构几何类型变化研究 总被引:1,自引:1,他引:0
冻融循环作用可通过影响寒区土体结构致使基础设施发生破坏,而导致工程失稳宏观现象的根源来自于冻融作用改变了土体的微观结构。为探索冻融作用下土体微观结构变化规律,将富平黄土作为研究对象,分别对其进行0、4、6、8、10、50、100次冻融循环下的电镜扫描观测试验,得到对应次数下的微观照片,对其从颗粒形态、连结方式、排列形式对孔隙的影响三方面进行分析,并且将微观照片中出现的颗粒接触方式以几何模型的方式进行归类,研究几何模型随冻融循环次数增加后的变化规律。结果表明:随着冻融循环次数的增加,土颗粒大小朝着均一性的方向发展,平均粒径呈先减小后增大趋势;颗粒的连结形式从面胶结为主逐渐演变为点接触为主最终再回归为面胶结为主;土体在0~6次冻融循环时孔隙率呈下降趋势,6~8次冻融循环时孔隙率快速上升,之后随着冻融循环次数的增加孔隙率逐渐减小;粒状粒子几何模型变化规律从棱边接触逐渐过渡为粒面接触,扁平状粒子几何模型变化规律从初始粒面接触为主逐渐演变为棱边接触为主,最终再演变为粒面接触。 相似文献
143.
藻类是泥炭地生态系统的重要组成部分,目前对泥炭地藻类生物多样性及生态特征报道较少。本研究以长白山金川泥炭地表层泥炭藓为试材,利用扫描电子显微镜分析附生硅质藻类遗存形态特征,发现大量硅藻壳体和金藻孢囊,还有少量金藻鳞片。这些金藻鳞片总体呈两头略尖的椭圆形,由圆顶、盾、V形肋、凸缘、刚毛等部分组成。鳞片长度范围在4~5μm,宽度范围在2~3μm。经比对前人研究,这些金藻鳞片属于金藻纲金胞藻目鱼鳞藻属(mallomonas)。金藻鳞片由于其硅质成分易于保存、分类特征明显且对环境变化响应敏感,是湿地环境监测和古环境重建的有效生物指标。目前我国金藻鳞片相关报道很少,需加强金藻鳞片分类学及生态属性调查,深入了解湿地藻类生物多样性,并为湿地环境评估提供新方法。 相似文献
144.
The distribution and characteristics of suspended particulate matter in the Chukchi Sea 总被引:2,自引:0,他引:2
Samples taken from the Chukchi Sea (CS) during the 4th Chinese National Arctic Research Expedition, 2010, were analyzed to determine the content and composition of suspended particulate matter (SPM) to improve our understanding of the distribution, sources and control factors of the SPM there. The results show that the SPM in the water column is highest in the middle and near the bottom in the south and central-north CS, followed by that off the Alaskan coast and in Barrow Canyon. The SPM content is lowest in the central CS. Scanning electron microscope (SEM) analysis shows that the SPM in the south and central-north CS is composed mainly of diatoms, but the dominant species in those two areas are different. The SPM off the Alaskan coast and in Barrow Canyon is composed mainly of terrigenous material with few bio-skeletal clasts. The distribution of temperature and salinity and the correlation between diatom species in SPM indicate that the diatom dominant SPM in the south CS is from the Pacific Ocean via the Bering Strait in summer. The diatom dominant SPM in the central-north CS is also from Pacific water, which reaches the CS in winter. The SPM in the middle and near the bottom of the water column off the Alaskan coast and in Barrow Canyon is from Alaskan coastal water and terrigenous material transported by rivers in Alaska. 相似文献
145.
《青岛海洋大学学报(英文版)》2014,(2):236-242
Molecularly imprinted polymers (MIPs) were prepared by the bulk polymerization using crystal violet as the template molecule, and the methacrylic acid and ethylene glycol dimetheacrylate as functional monomer and cross-linker, respectively. Sys- tematic investigations of synthetic conditions were conducted. The surface morphology and recognition mechanism of the obtained polymers were studied using scanning electron microscope and spectrophotometric analysis. MIPs showed high atTmity to template molecule and were successfully applied as special solid-phase extraction sorbent for selective extraction of crystal violet from natural seawater. An off-line molecularly imprinted solid-phase extraction (MISPE) method followed by high-performance liquid chroma- tography with diodearray detection for the analysis of crystal violet was also established. MISPE columns have good recoveries for crystal violet standard solutions and good linearity was obtained over the concentration range of 0-200 ~tg L-1 (R2 〉 0.99). Finally, two natural seawater samples were investigated. The recoveries of spiked seawater on the MISPE columns were from 44.47% to 62.34%, the relative standard deviation (n=3) being in the range of 2.89%-5.96%. 相似文献
146.
不同剪切作用下CMC水溶液的微观结构研究 总被引:1,自引:0,他引:1
针对聚合物钻井液重要组分之一的羧甲基纤维素钠盐(CMC),考虑钻井液在井底钻头与环空处所受的不同剪切作用,测试了其水溶液在相应近似剪切作用(分别为600,6 000 r/min)下的流变性,并结合冷冻干燥方法,利用扫描电子显微镜观测了这两种剪切作用后CMC水溶液相应的微观结构.结果表明高速剪切作用使CMC水溶液的空间网络骨架拉伸变细,甚至破坏,溶液黏度有所降低,流动性增大.这样,热量更容易通过这些网络骨架,使充填其中的小分子物质以热传导、对流传热等方式传递到钻屑表面,分解钻屑表面的水合物.水合物分解产生的气体和水则以分子扩散的形武向内向外进行传质,但会受到钻井液微观骨架结构和其中填充物质的阻碍. 相似文献
147.
SHEN Junfeng YANG Weimin LIU Ting HUANG Xiao ZHENG Weijie YU Lei WANG Guoqiang 《《地质学报》英文版》2014,88(4):1131-1144
Much important information referring to fault motion (e.g., fault activities period, intensity, frequency, and even dynamic background) can be revealed by resolving fault gouge, which is the result of fault motion while extruding or grinding. The field investigation encompassed sample collecting from the Bailong River fault system of the western segment of the Qinling Orogenic Belt (QOB); 44 samples of fault gouges were collected for quartz micro-morphology analysis. These samples were analyzed using field emission scanning electron microscopy. In addition, 14 samples were tested for thermo-luminescence dating. The results showed that most of the surface textures of quartz grains are characterized by fish scale, moss-like texture, and stalactite. However, a small amount of orange peel-like fractures and worm-hole-like shaped surface texture were observed. Moreover, a few typical conchoids or subconchoidal fractures in quartz grains can be seen. This implies that the Bailong River Fault was active repeatedly during the Quaternary period, but the main motion period is the Pleistocene. The 14 thermo-luminescence dating values showed two age groups: 343.29-184.06 ka and 92.18-13.87 ka. These study data reveal that fault movement started during the Pliocene, occurred frequently in the early-middle period of the Pleistocene, and the peak frequency of the motion was reached in the early Pleistocene. The fault motions were stopped terminated in the early Holocene. The results are significant for the natural disaster risk evaluation in the western segment of the QOB. 相似文献
148.
149.
紫色“山仔濑石”为寿山石的一种,是一种由层状硅酸盐矿物组成的黏土质玉石。其表层风化为黄色,内部为紫色,属于图章石中较为稀少的颜色品种。本文采用常规的宝石显微镜对其外观特征进行详细观察;利用X射线粉晶衍射仪、显微激光拉曼光谱仪、扫描电子显微镜、激光剥蚀等离子质谱仪等对其矿物组成、化学成分、稀土元素特征及谱学特征进行测试;利用全岩化学分析、紫外-可见光分光光度计、SPSS分析模型对其颜色成因进行研究。结果发现紫色“山仔濑石”的主要矿物组成为伊利石,次要矿物为独居石、磷钡铝石、赤铁矿和重晶石;其稀土元素指示性数据呈现出轻稀土元素富集,重稀土元素亏损的现象,指示其矿物成因与还原的酸性热液蚀变有关;紫色“山仔濑石”的紫色色调深浅与伊利石中Mn含量高低呈现正相关性;紫色“山仔濑石”内主要矿物和次要矿物的种类、分布特征和形成温度的不同说明在成矿后期存在多期热液侵入,紫色“山仔濑石”的形成过程与寿山地区的成矿规律具有一致性。 相似文献