南海北部珊瑚Ba/Ca比值的季节变化及其环境意义

利用等离子体质谱技术分析了取自海南岛南部沿岸的现代滨珊瑚高分辨率的Ba／Ca比值。结果表明，该珊瑚的Ba／Ca比值具有明显的双峰态的季节变化，其中春季和秋季Ba／Ca比值较高，而冬、夏两季则较低。海南岛南部及邻近地区季节降雨的变化所控制的陆源Ba输入是这些珊瑚Ba／Ca比值变化的重要控制因素，而该区夏季相对较高的表层海水生产力可能也对其有重要影响。High-resolution Ba/Ca ratios of a modern Porites coral from Sanya Bay, offshore of Hainan Island, were measured by ICP-MS. The results exhibit seasonal periodical ventilation of the coralline Ba/Ca ratios with higher Ba/ca ratios in spring and autumn and lower in winter and summer. variation of the terrestrial Ba flux to this area,which was controlled by seasonal precipitation of Southern Hainan Island and surmunded areas, is the key role to these Ba/Ca patterns. On the other hand, the relatively high surface productivity of the area in summer may contribute to the lower Ba/Ca ratios of the coral.postprin

珊瑚中微量铀的ID-ICP-MS 高精度测定及其在珊瑚U/Ca 温度计研究中的应用

建立了同位素稀释技术与IC-MS 相结合的ID-ICP-MS 分析方法, 成功测量了取自南海北部的滨珊瑚样品中的微量铀, 获得0.5% 左右的精度。并以此建立南海北部近岸海域的珊瑚U/Ca 温度计, 其温度精度可达士0.5 ℃。ID-ICP-MS, an analytical method that combines isotope dilution technique and ICP-MS method had been developed in our laboratory. Trace uranium of the coral samples from the northern area of the South China Sea had been measured to an accuracy of 0.5%. Depended on these results, a high resolution coral U/Ca thermometer for thes area was established. Monthly average SSTs with a precision of ±0.5℃ were attainable by this U/Ca thermometer.published_or_final_versio

汉诺坝玄武岩中麻粒岩和辉石岩捕虏体Sr-Nd-Pb同位素五维空间特征及其地质意义

研究了汉诺坝玄武岩中麻粒岩和辉石岩捕虏体在Sr-Nd-Pb同位素五维空间中的特征 .结合捕虏体的空间分布相对位置, 认为层离作用可较好地解释不同类型捕虏体同位素之间的相互关系。published_or_final_versio

Petrochemistry and mineral chemistry studies on metamorphic ultramafic rocks in Yanghou area, Zhenghe Country, Fujian Province, China

Petrochemistry studies indicate that the Yanghou metamorphic ultramafic rocksare composed of metamorphosed harzburgite and burgite and ultramafic cumulate . Trace element geochemistry and mineral chemistry studies on the metamorphosed harzburgite indicate that it is the relict of the depleted mantle. From systematic studies on petrochemistry , mineral chemistry and geochronology, it s concluded that the Yanghou metamorphic ultramafic rocks are components of Later Sinian-Early Paleozoic ophiolite in South China.岩石化学研究表明, 洋后变质超镁铁岩是由变质方辉橄榄岩和变质超镁铁堆积岩组成。变质方辉橄榄岩的微量元素地球化学及矿物化学特征表明, 应为亏损的残余地慢产物。通过系统的岩石地球化学、矿物化学及年代学研究, 认为洋后变质超镁铁岩可能为华南晚震旦一早古生代的蛇绿岩组成部分。published_or_final_versio

Monolayer Protected Gold Nanoparticles: Application in Molecular Recognition

In the last years, a relevant attention has been paid to monolayer protected gold nanoparticles (AuNPs), which are nanometer-sized gold colloids coated with a monolayer of organic molecules. Indeed, they have several interesting features.The first one is the easiness to synthesize gold cores with various sizes. Second, the versatile chemistry of AuNPs allows the grafting of functional groups and co-factors onto their surface. Taking advantage of different kinds of non-covalent interactions (namely hydrophobic, ion pairing, and metal-ligand coordination), such functional groupscan in turn provide tailored binding sites for virtually any class of substrates. The variety of monolayers that can be potentially assembled endows a fine-tuning of these interactions not only in terms of selectivity, but also in terms of their strength. Therefore, AuNPs were emerging as great scaffolds for molecular recognition. In this thesis, chapter 1, the introductive chapter, will present the methods for the preparation of AuNPs, the recent progress of AuNPs as chemosensors and the approaches that have been developed to investigate the monolayer morphology of mixed AuNPs. In chapter 2, the aims and objectives of this thesis will be addressed. In chapter 3 and 4, a series of water soluble AuNPs were prepared and investigated as nanoreceptors and chemosensors using nuclear magnetic resonance (NMR) protocols. The results of chapter 3 indicated that by appropriate design of the coating ligands, the spontaneous formation of the sensing pockets in the monolayer of the gold nanoparticles can be achieved. The results in chapter 4 confirmed the possibility that the rational design of AuNPs with intrinsic binding cavities and controlled sensing ability can be aided by molecular dynamic (MD) simulations. In chapter 5, three kinds of positive charged AuNPs were prepared and they were able to detect and discriminate nonsteroidal anti-inflammatory drugs in a quantitative manner. In the field of molecular recognition, unique properties can also be obtained by the preparation of mixed AuNPs. Previous studies have already demonstrated that the morphology of the mixed monolayer is closely related to their properties. For this reason, in chapter 6, we will describe a method which combines NMR and electron paramagnetic resonance (EPR) techniques to investigate the morphology of mixed AuNPs. Furthermore, in chapter 7we demonstrated that the morphology of the mixed monolayer can be transformed when in the presence of proper interacting analytes

Coralline Sr/Ca and Mg/Ca thermometer for the northern South China Sea: calibration and primary application high resolution on high-resolution SST reconstructing

利用全谱直读等离子体光谱(ICP2AES) 的分析方法精确分析了南海珊瑚的SrPCa 和MgPCa 比值,结合实测表层海水温度(SST),标定了海南岛南部三亚海域和西沙海域两个滨珊瑚的SrPCa 和MgPCa 温度计。在此基础上,尝试对两个南海北部全新世时期的珊瑚进行SST记录重建。结果显示约540aB.P. (小冰期) 西沙海域夏季月均SST 较现代低约1℃,而约6 500aB.P. (大暖期) 海南岛三亚海域夏季月均SST则高出现代1.0～1.5℃。The method for precisely and simultaneously measuring the coralline Sr/Ca and Mg/Ca ratios was established using inductively coupled plasma atomic emission spectrometry (ICP-AES). Using this method, the high-resolution Sr/Ca and Mg/Ca ratios of two Porites lutea from Sanya, South Hainan Island and Xisha Islands were measured. By comparing to the instrumentally measured sea surface temperatures in these two areas, the coralline Sr/Ca thermometer and the Mg/Ca thermometer were calibrated. These two thermometers can provide SST records with an error bar < 0.2℃, and they are suitable for high-resolution SST reconstructions in these areas. Based on these two thermometers, two short SST records were reconstructed from two Holocene Porites corals of the northern South China Sea. The results indicated that the monthly summer SSTs in Xisha Islands at about 540 years ago (the Little Ice Age) were 1℃ lower than that at present, and the monthly summer SSTs in Sanya, southern Hainan Island at 6 500 years ago (the Megathermal) were about 1℃ to 1 5℃ higher than that at present.published_or_final_versio

下地壳及壳慢过渡带化学不均一性 -- 河北汉诺坝地区深源捕虏体元素地球化学证据

河北汉诺坝玄武岩中长英质麻粒岩、镁铁质麻粒岩和辉石岩捕虏体的主量元素和微量元素特征, 反映了下地壳及壳鳗过渡带组成具有高度化学不均一性。不相容元素原始地慢标准化曲线特征的差异表明捕虏体成因复杂。MgO 与不相容元素无或仅有很弱的相关性, 与相容元素的相关性则相对较明显。这些特征反映了下地壳及壳慢过渡带存在较强和多元的混合作用。捕虏体的加权平均值比基于麻粒岩地体资料估算的下地壳平均组成偏基性, 揭示了二者可能的成因差异。The major and trace element data of granulite and pyroxenite xenoliths, which are entrained in Hannuoba basalt Hebei Province, North China, suggest the highly chemical heterogeneity in the lower crust and crust-mantle transitional zone. There is no or only POor linear correlation between MgO and incompatible elements. Whereas a bit remarked correlations are observed between MgO and most compatible elements.The geochemical characteristics suggest that the strong and multiple mixing processes may have Occurred universally both in the lower crust and crust-mantle transitional zone. The weighed average composition of xenoliths shows a more mafic composition of the lower crust than that estimated from granulite data, which may imply the difference in the genesis.published_or_final_versio

Sr, Nd Pb isotopic characteristics of granulite and pyroxenite xenoliths in Hannuoba basalts, Hebei Province, and their implications for geologic processes

Rb-Sr, Sm-Nd and Pb isotopic systematics are reported for granulite and pyroxenite xenoliths in Hannuoba basalts, Hebei Province. The isotopic characteristics of xenoliths suggest t hat they might have formed recently , although there is no strict constraint on the precise age. The decoupling of low Rb/Sr and high [87]Sr/[86]Sr ratios implies the multi-stage evolution history and strong mixing processes. There are close ties between granulite and pyroxenites with different mineral assemblages on the Sr-Nd, Pb-Sr and Pb-Nd correlation figures. The granulite is the common end-member o f the three kinds o f pyroxenite. Combined with the distribution of the xenoliths in space and their isotopic relationships, It is proposed that delamination can be well used to explain the ties.系统研究了河北汉诺坝玄武岩中二辉麻粒岩和辉石岩捕虏体的Sr、Nd、Pb 同位素特征。虽然未确定捕虏体的形成时代, 但同位素特征显示它们可能为较近期( 中生代以来) 形成。低的Rb/Sr 与高 的[87]Sr/[86]Sr 比值的解耦表明捕虏体的形成经历了较强的混合作用。在二元同位素相关图上, 三类具不同矿物组成的辉石岩与二辉麻粒岩有密切关系, 即二辉麻粒岩投点位置是三类辉石岩的共同端点。综合考虑捕虏体的空间分布及其在Sr 、Nd、Pb 同位素协变图上的关系, 可以认为层离作用可较好地解释这些现象。published_or_final_versio

Study on GMZ bentonite-sand mixture by undrained triaxial tests

© 2016 The Authors. It is particularly necessary to study the deformation, strength and the changes of pore water pressure of bentonite-based buffer/backfill materials under the undrained condition. A series of isotropic compression tests and triaxial shear tests under undrained conditions were conducted on the compacted saturated/unsaturated GMZ bentonite-sand mixtures with dry mass ratio of bentonite/sand of 30:70. During the tests, the images of the sample were collected by photographic equipment and subsequently were cropped, binarized and centroids marked by image processing technique. Based on identification of the variation of the position of marked centroids, the deformation of the sample can be determined automatically in real-time. Finally, the hydro-mechanical behaviour of saturated and unsaturated bentonite-sand mixtures under the undrained condition can be obtained. From results of triaxial shear tests on unsaturated samples under constant water content, inflated volumetric deformation transforms to contractive volumetric deformation due to the increase of the confining pressure and lateral expansion deformation are observed due to the increase in the shearing stress. Moreover, the net mean stress affects the initial stiffness, undrained shear strength and deformation of the sample during the undrained shear tests

Highly heterogeneous Late Mesozoic lithospheric mantle beneath the North China Craton: evidence from Sr–Nd–Pb isotopic systematics of mafic igneous rocks

The lithospheric mantle beneath the North China Craton changed dramatically in its geophysical and geochemical characteristics from Palaeozoic to Cenozoic times. This study uses samples of Mesozoic basalts and mafic intrusions from the North China Craton to investigate the nature of this mantle in Mesozoic times. Sr-Nd-Pb isotopic data demonstrate that the Late Mesozoic lithospheric mantle was extremely heterogeneous. In the central craton or the Luzhong region, it is slightly Sr-Nd isotopically enriched, beneath the Taihangshan region it has an EMI character (87Sr/86Sri = 0.7050-0.7066; εNd = -17--10), and beneath the Luxi-Jiaodong region, it possesses EM2-like characteristics (87Sr/86Sri up to 0.7114). Compositional variation with time is also apparent in the Mesozoic lithospheric mantle. Our data suggest that the old lithospheric mantle was modified during Mesozoic times by a silicic melt, where beneath the Luxi-Jiaodong region it was severely modified, but in the Luzhong and Taihangshan regions the effects were much less marked. The silicic melt may have been the product of partial melting of crustal materials brought into the mantle by the subducted slab during the formation of circum-cratonic orogenic belts. This Mesozoic mantle did not survive for a long time, and was replaced by a Cenozoic mantle with depleted geochemical characteristics. © 2004 Cambridge University Press.published_or_final_versio