菊花石中纳米矿物的微观组织研究

采用扫描电镜、透射电镜和能谱分析研究了浏阳产菊花石的微观组织,发现浏阳菊花石的花瓣保留了原生矿物——天青石SrSO₄及其单晶体的外形,但是花瓣内部出现了硅化现象;菊花石中存在多种纳米矿物材料,例如非晶纳米硅氧线、颗粒状纳米CaCO₃和SrSO₄、CaCO₃的二维纳米片和纳米带等。某些非晶纳米硅氧线外包覆了纳米晶化层,镁含量越高,非晶纳米线越容易晶化。     

Chemical evidence of water movements in the deepest part of Lake Leman (Lake Geneva)

Regular surveys of bottom water chemistry (SiO₂, O₂, Fe, Mn) have been carried from 1978 to 1986 in the deepest 30 m of Lake Léman (max. depth 309 m) including interface waters sampled with a Jenkins Mortimer corer. When compared to normal chemical gradients near bottom, i.e. O₂ decrease and SiO₂ increase, three types of anomalies (lens, interface, and behaviour) have been observed on O₂ and SiO₂, the most sensitive chemical species. These anomalies were found throughout the year, in several stations of the deepest part of the lake and even along the slope of the lake basin. Major anomalies (O₂ + 3 to 10 mg ·l^–1; SiO₂ -1 to 2 mg·l^–1) were generally found at the sediment water interface and may extend 10–20 m above the sediment and last 10 weeks. Others marked lens anomalies could be observed for 3 to 4 months. Several mechanisms are probably responsible for this injection of surface waters along the lake slope (accumulation of turbid water on lake banks after severe windstorms; river density currents due to temperature and/or turbidity difference with lake waters). These water-inputs do not represent important volumes ( 1% total lake volume) but, when occuring at the interface, they ensure a sufficient oxygen level to prevent diffusion of phosphate and ammonia from pore waters when winter lake overturns do not reach bottom layers (from 1972 to 1980). Complete overturns, as observed in 1980/81, are connected with major interface anomalies (bottom O₂ moves up from 2 to 10 mg·l^–1) occuring before surface mixing reaches the deepest layers.     

古赤潮与古营养状况的沉积记录研究进展

大量的研究证实，赤潮与海水的富营养化有密切的关系。近年来，国内外一些学者通过分子地层学记录来探讨赤潮演变历史及其与富营养化的关系，希望找到赤潮演化与发展的科学依据。本文综述了甾醇、生物硅、色素、孢囊、同位素等指标在古赤潮及其相关古营养研究中的应用及研究动态与进展。甾醇是重要的藻类生物标志化合物，4-甲基甾醇及其衍生物可指示沟鞭藻的输入。孢囊可用来反映生物种群、表层海水营养和生产力水平。生物硅被用来指示硅藻生产力。色素可以很好地反映水体中富营养水平及生产力高低，颤藻黄素的升高被认为是湖泊人为富营养化的重要依据。利用C、N同位素组成的变化指示水体中营养状况的变化。     

C18键合硅胶柱在线富集/FIA-FAAS系统测定海水中痕量重金属

基于8-羟基喹啉金属螯合物在C_(18)键合硅胶上的吸附原理,在海水样品中加入少量8-羟基喹啉溶液,建立在线C_(18)键合硅胶柱富集,甲醇洗脱,洗脱液直接进入火焰的流动注射-火焰原子吸收光谱系统(FIA-FAAS)测定海水中痕量Cu,Ni,Cd和Zn的方法。富集倍数达80,进样频率为每小时30次。对Cu Ni,Cd和Zn测定的特征浓度分别为0.30,0.26,0.12和0.07μg/L;检出限(2σ)分别为0.07,0.05,0.02和0.01μg/L;相对标准偏差分别为2.7,2.1,2.8和2.5％;回收率分别为102,98,96和102％。本法快速简便,污染少,灵敏度高。     

High Performance Concrete and Its Typical Mixes

- With the modern development of chemical and mineral admixtures, it is now possible to produce much higher performance concrete than before. Higher performance does not only mean higher strength, but also better durability, lower risk of thermal cracking and higher dimensional stability etc. The three most effective admixtures for producing high performance concrete are superplastieizer, pulverized fuel ash and condensed silica fume. This paper outlines the properties of these materials and presents some practical guidelines for their usage.     

南海ODP1148站深海相渐新统硅质成岩作用

南海ODP1148站分析结果显示，井深475-600m的硅质化石主要表现为蛋白石-CT。随着深度增加，硅质化石破壳率增大，蛋白石-CT的X射线衍射峰强度减弱，自生石英的衍射峰则相应增强，反应了蛋白石-CT向石英的转变，井深620m附近，硅质化石完全溶解，蛋白石-CT衍射峰消失，蛋白石-CT全部转变为石英，样品取心率从470m处的近100%降到485m处的8%，可能是硅质成岩作用，尤其是蛋白石-A向蛋白石-CT的转变影响所致，而取心率的降低，则是此井未能观察到蛋白石-A/蛋白石-CT转变界线的部分原因。     

红土型三水铝土矿的一种新分类方法

由于已知国内的红土型三水铝土矿矿床均为小型,且矿石质量也偏差,多为小规模开采利用,而国外多为大型—特大型矿床,质量也好.笔者长期在境外开展红土型三水铝土矿的资源勘探和资源评价工作.在结合矿山开采的选矿工作和生产氧化铝的拜耳法工艺,对红土型三水铝土矿按照边界品位即是否需要洗矿,提出了全新的分类方法.     

从太平洋中部热液矿物的表现探讨热液活动的广泛性

位于太平洋中部的克利帕顿和克拉里昂断裂带之间的研究区处于远离大陆的远洋深水环境，区内断裂构造和火山活动非常发育，热水活动强烈，由此形成一系列与热液活动及蚀变沉积有关的矿物，如磷灰石、碳磷灰石、稀土磷灰石、磷铝锶石、重晶石、碳酸钡矿、泡饿矿及非晶质ＳｉＯ２球。这都说明大洋中热水溶液活动并不仅限于洋脊轴部和裂谷地区，只要有较大规模的断裂存在，就会有热水溶液活动或海底热泉出现，随之后形成一系列与热液活动     

Molar refraction of quartz family minerals

Different polymorphs of silica and the opals exhibit significant variations in densities. The paper discusses and correlates the variations in the molar refraction with density. It emerges that in different polymorphs of silica, the increase in density involves a corresponding increase in the characteristic dispersion frequencies leading to a decrease in the molar refraction. The variation of the molar refraction with density can be represented in terms of an elementary formula. The variation of the molar refraction of opals with the water content in them is also accounted for.     

Aquatic system response to climatic and human changes: Productivity,bottom water oxygen status,and sapropel formation in Lake Lugano over the last 10 000 years

The Holocene record of Lake Lugano (southern basin: surface area 20.3 km², maximum depth 87 m) comprising organic carbon-rich sediments (sapropels), is divided into eight intervals based on radiocarbon- and varve-dating. The content of organic carbon, inorganic carbon, and biogenic silica, as well as the benthic remains of ostracods and oligochaetes, are converted into accumulation rates and benthic abundances in order to assess past production rates and bottom water oxygen status, respectively. The results suggest three periods of distinct palaeolimnological character: (i) low primary production combined with shifts between aerobic and anaerobic profundal conditions (prior to ca. 3000 BC), (ii) moderate rates of production combined with a relatively high profundal oxygen content (after ca. 1500 BC), and (iii), high production rates (460 g C m^–2 a^–1) combined with anaerobic profundal conditions (present eutrophic state). Corresponding organic carbon contents in the sediments are: up to 5% (i), 4% (ii), and 8% (iii). Until the beginning of this century, the flux of autochthonous sediments to the lake floor correlated with the fluctuations in the allochthonous sediment accumulation rate, indicating that catchment erosion largely controlled lacustrine production during the Holocene history of Lake Lugano. Pollen data show catchment-vegetational transformations at ca. 3500 BC (change from fir to beech forests), at 1400 BC (onset of cereal vegetation) and at ca. A.D. 450 (strong increase in various cultural plants). The first two changes had a relatively large imprint on lacustrine sedimentation. At ca. 3500 BP, erosion increase in the catchment was triggered by vegetation changes in the mountain zone above ca. 1000 m a. s. l., which may have been induced by climatic and human alteration (drop in the treeline altitude). Maximum catchment erosion occurred at ca. 1400 BC which was clearly dominated by human cultivation during the Bronze Age. More oxygenated profundal conditions in the lake after ca. 3000 BC are possibly related to a better mixing of the lake waters during the winter season by increased wind activity.