Stratigraphical and biological significance of negative carbon isotopic anomalies in the basal Cambrian series of Guizhou Province

The early Early Cambrian strata within the bounds of Guizhou Province are almost predominated by black shale deposition. Recently, however, the authors have found a section consisting of a set of mudstones interbedded with limestones at the basement of the Cambrian at Yingping, Fuquan County, Guizhou Province, which provides favorable conditions for the study of marine geochemical characteristics of the early Early Cambrian. The characteristics of intense negative carbon isotopic anomalies near the Precambrian/Cambrian boundary at Yingping, Fuquan County, Guizhou Province, can be correlated with those of global carbon isotopic anomalies at the same time on a global scale, corresponding to the intense negative carbon isotopic anomalies near the Neoproterozoic/Cambrian boundaries at the bottom of the Xiaowaitoushan Member, Huize, Yunnan Province, at the top of the Tsagaan Oloom Formation of Mongolia and at the top of the Salarmy Gol Formation of Siberia, as well as those observed in southwestern United States, Iran, Amman, Poland, Newfoundland, the Great Britain, Canada, etc. Negative carbon isotopic anomalies can be used as the important basis for the division of the Precambrian/Cambrian boundaries. There have been found 8 m-thick black shales and cherts below the intense negative carbon isotopic anomalies in this profile. In the black shales there have been found large amounts of fossils such as Bradorida, gernus Archotuba, indicating that during the period of sedimentation of black shales under anaerobic conditions there would be large quantities of organic species living in the sea. But in the section of grayish-green mudstones interbedded with limestones with intense negative carbon isotopic anomalies almost no organic fossil has been found. This may imply that the anaerobic event seems to have little bearing on the mass extinction near the Precambrian/Cambrian boundary, whereas the intense negative carbon isotopic anomaly event appears to be more closely related to the mass extinction occurring near the Precambrian/Cambrian boundary.

Hydrogeochemistry of karst underground waters at shallow depth in Guiyang City, Guizhou Province

The aim of this study is to shed light on the hydrogeochemical characteristics of karst underground waters at shallow depth in Guiyang City, Guizhou Province with an emphasis on the geochemistry of major elements. Guiyang City bears abundant underground waters and it is also an important representative of the karst areas throughout the world. Ca+{2+} and Mg+{2+} are the dominant cations, accounting for 81%-{99.7%} of the total, and HCO+--3 and SO+{2-}-4 are the dominant anions. Weathering of limestones and dolostones is the most important factor controlling the hydrogeochemistry of underground waters, and weathering of sulfate and evaporite rocks is less important. Moreover, the precipitation and human activities also have a definite influence on the hydrogeochemistry of underground waters in the region studied.

Study on the Flocculability of Metal Ions by Bacillus Mucilaginosus GY03 Strain

这研究处理金属离子 byBacillus mucilaginosus GY03 紧张的二种类型的 flocculability ，与 pH 条件的影响上的一个重音， GY03 生产的凝聚剂的体积和时间在象Pb2+和Mn2+和凝聚剂的能力那样的金属熨斗的吸附上拉紧吸附不同集中的金属离子。结果证明微生物引起的凝聚剂生产了 byBacillus mucilaginosus GY03 紧张高度能够絮凝金属离子，而是表演关于 Pb2+ 和 Mn2+ 的吸附的不同有效性。根据试验性的数据和实际废水处理条件，絮凝的相关回归方程被推出了，它在实践发现了一些申请。这研究的试验性的结果证明微生物引起的凝聚剂生产了 byBacillus mucilaginosus 能被用来对待金属性的包含离子的浪费水。在实际申请，微生物引起的凝聚剂的体积要求了，絮凝条件应该根据金属离子，阴离子的作文和另外的金属的溶解度的性质被拿进全面考虑，在有要过去常的凝聚剂的费用和有效性的联合。在这个实验使用的凝聚剂有的优点在絮凝的大量 pH 值，小凝聚剂卷，和快速的速度上被使用。这种凝聚剂因此在申请的优秀前景以内。关键词微生物引起的凝聚剂 - 杆菌 mucilaginosus - 硅酸盐细菌 - flocculability - 废水处理这个研究工程被州的关键实验室财政上联合支持。中国科学院(HDH010901 ) 和中国的环境地球化学基础博士后的科学基础(2003033496 ) 。

Sedimentary and Geochemical Characteristics of Sinian Cap Carbonates in the Upper Yangtze Region

A global\|scale glaciation occurred at about 600 Ma ago. As a result, the Earth became the "Snowball Earth". The glaciation came to the end abruptly when atmospheric carbon dioxide increased to such an extent as to be about 350 times the modern level because of subaerial volcanic degassing. The rapid termination of glaciation would have led to warming of the Snowball Earth and extreme greenhouse conditions would have been created. The transfer of atmospheric carbon dioxide to oceans would give rise to the rapid precipitation of calcium carbonate in warm surface seawaters, thus forming the cap carbonate rocks as observed worldwide today.\; Regionally persisting, thin layers of carbonate rocks directly and ubiquitously overlie Proterozoic glacial deposits almost on every continent, and are commonly referred to as cap carbonates. Their unusual litho\| fabrics, stratigraphically abrupt basal and upper\|level contacts and strongly negative carbonate isotopic signatures (\{δ\{\}\+\{13\}C\-\{carb.\}\} values range from -7.0‰-0‰) suggest a chemical oceanographic origin, the details of which remain unknown. It is proposed that these enigmatic deposits are related to the destabilization of gaseous hydrate in terrestrial permafrost following rapid postglacial warming and flooding of widely exposed continental shelves and internal basins.\; The authors carried out studies on the geochemistry, sedimentology and palaeontology of the Sinian cap carbonates in Guizhou and Hunan provinces, including the occurrence of cap carbonates of unusual fabrics, strongly negative carbon isotopic signatures, and a lot of bitumen nodules. From the results it is suggested that the cap carbonates were formed from solid methane seepage, and it is in agreement with Kennedy’s viewpoint (2001) that the cap carbonates resulted from the rapid precipitation of calcium carbonate in response to solid methane seepage.

Thermal Fatigue Behaviour of Co-Based Alloy Coating Obtained by Laser Surface Melt-Casting on High Temperature Alloy

A thermal fatigue behaviour of Co-based alloy coating obtained by laser surface meltcasting on the high temperature alloy GH33 was studied.The results show that after each time of thermal cycling,the final residual stress was formed in the melt-casting layer which is attributed to the thermal stress and structural stress.Through the first 50 times of thermal cycling,the morphology of coating still inherits the laser casting one,but the dendrites get bigger;After the second 50 times of thermal cycling,corrosion pits emerge from coating,and mostly in the places where coating and substrate meet.The fatigue damage type of coating belongs to stress corrosion.

Lanmuchangite, a New Thallium (Hydrous) Sulphate from Lanmuchang, Guizhou Province, China

Lanmuchangite is a new thallium hydrous sulfate from the oxidation zone hosting rich thallium ore bodies in the Lanmuchang thallium(mercury) ore deposit, Xinren County, Guizhou Province, China. This new mineral is named after the locality where it was discovered. The mineral is associated with melanterite, pickeringite, potassium alum, jarosite, gypsum, arsenic blane, sulphur and some unknown minerals. The aggregates of lanmuchangite range from 2 to 10 mm in size. In general, the aggregates are compact and massive in form and are composed of anhedral granular crystals measuring in size from 40 to 90μm, but the single crystal grains show distinct boundaries. Parallel columnar aggregates are occasionally seen, which are composed of subhedral to euhedral columnar crystals ranging in size from 15 to 65μm. White, light yellow to white in color, glassy in luster and transparent. Hv-{mess.}=94-124 kg/mm+2, Hm={3.1}-{3.4}, density={2.22} g/cm+3. Under the polarization microscope the mineral is colorless and homogeneous, with N-{meas.}={1.495}. It is easily water-soluble. The average chemical composition is: Tl-2O={33.25}, Al-2O-3={8.07}, SO-3={25.19}, SiO-2={0.10}, K-2O={0.35}, CaO={0.08}, MgO={0.06}, FeO={0.04} and H-2O={33.46} [the crystal water (H-2O) was measured by thermogravimetery (TG) while the other composition were determined by electron microprobe], totaling {100.60%}. The empirical formula is (Tl-{1.00}K-{0.05})-{1.05} (Al-{1.01}Si-{0.01}Ca-{0.01}Mg-{0.01})-{1.04}-{2.01}·{11.88} H-2O and the simplified formula is TlAl-2·12H-2O. The compatibility of lanmuchangite is {-0.03} and its value falls within the range of {±0.020}-{±0.039}, so the compatibility is excellent. Its TG curve demonstrated that the crystal water was lost (i.e., dewatering) in stages at 101, 130 and 230℃. At the temperature of 243℃ the process of dewatering came to the end and the sum of lost crystal water reaches {33.30} wt%. IR spectroscopic analysis showed that the absorption bands 3374-3147 cm+{-1} and 1655-1648 cm+{-1} are due to tensile and bending vibration of crystal water molecules (H-2O) whereas those at 1131 cm+{-1} and 605 cm+{-1} are attributed to tensile and bending vibration of group +{2-}. Lanmuchangite is of the isometric system, with space group=Pa3, a={12.212(5)}, v=1821(2)+3, and Z=4. The strongest diffraction lines from the X-ray power diffraction data are {4.314}(100, 220), {2.801}(70, 331), {7.03}(54, 111), {2.731}(35, 420), {6.11}(27, 200), {3.524}(24, 222), {3.676}(22, 311), {3.051}(22, 400), {2.350}(21, 511), {3.263}(20, 321), {2.494}(20, 422), {1.932}(19, 620).

Distribution behavior of Copper and Tin between FeO-rich slag and iron solution

The distribution behavior of residual elements copper and tin between FeO rich slag and iron solution was investigated under the condition of an induction furnace. The results indicate that a part of copper and tin is incidently oxidized when oxygen is blasted into bath to react with iron element. The distribution ratio of copper and tin between slag and metal is about 0.1. Phenomena of Cu and Sn elements segregation and accumulation in slag were observed by means of EPMA analysis. The distribution ratio of copper and tin between slag and metal may descend with increasing of CaO content in slag.

Calcination-Digestion-Desliming of Phosphorus Ore Bearing Rare Earth

The recoveries of phosphorus and RE of ore from Zhijin in Guizhou were studied.The influences of the calcination temperature, resident time, the digested time and water volume of the calcinating on concentrate yield by desliming were also investigated by orthogonal design.Appropriate calcination temperature is initial condition that makes carbonate mineral decomposition.The recovery of phosphorus is 83.02% and rare earth is 90.56% in phosphorus concentrate when calcined temperature is 900 ℃, other conditions include: calcined time is 30 min, digestion water volume is 300 ml, digestion time is 20 min.The results show that the pre-treatment of the ore is favorable for the separation and enrichment of rare earth from phosphorus ore, and a process of calcination-digestion-desliming was promised.

Hydrothermal Redistribution of Rare-Earth Elements in Pingxiang Dacite, Guangxi

Distribution of the rare-earth elements (REE) in dacite has been studied so as to get a better understanding of the migration behavior of REE during alteration. Both unaltered and altered samples were collected in an unpolluted area of Guangxi Zhuang Autonomous Region, southwest China. The REE concentrations were analyzed by ICP-MS. It is concluded that the REE were enriched during dacite alteration in varying degrees. The chondrite-normalized REE patterns of altered samples approximately maintain the characteristics of unaltered samples. However, if we normalize the REE concentrations of altered samples with unaltered dacite, fractionation of REE will appear. The LREE are more enriched than HREE in all altered samples with the LREE possibly precipitated as carbonate minerals. Both positive and negative Eu anomalies exist. Enrichment, immobility and depletion are noticed for the element Lu. Heavy mineral alteration, difference in stability constant between carbonate LREE and HREE complexes, downward migration of weathering fluid and microenvironment change may be responsible for the fractionation of REE in the altered dacite.

A CONTINUUM DAMAGE MODEL OF AGING CONCRETE

There is up to now no constitutive model in the current theoriesof CDM that could give a description for the degradation of agingconcrete. The two internal state variable β and ω are intro- ducedin this paper β is called cohesion variable as an additionalkinematic parameter, reflecting the cohesion state among materialparticles. ω is called damage factor for micro-defects such s voids.Then a damage model and a series of constitutive equations aredeveloped on Continuum Mechanics. The model proposed could give avalid description for the whole-course-degradation of aging concretedue to chemical and mechanical actions. Finally, the validity of themodel is evaluated by an example and experimental results.

Exact Solution for a Chain of Coupled Oscillators with Two Types of Atom

A quantum transformation that can diagonalize the Hamiltonian of a ring of N coupled diatomic oscillators is found. By means of the transformation, the dispersion relation of the atomic system is obtained. For large N it turns out that the dispersion relation resembles to the phonon spectrum of the lattice vibration derived by Newton's equation of motion.

Negative carbon isotopic excursion on the Lower/Middle Cambrian boundary of Kaili Formation, Taijiang County, Guizhou Province, China: Implications for mass extinction and stratigraphic division and correlation

The stratigraphic division and correlation of the Lower/Middle Cambrian boundary is a global problem that has not yet been perfectly solved up to now. That is because there existed two global biogeographic regions during the period from Early Cambrian to Middle Cambrian. Although much work has been done from the angle of paleontology and great achievements have been acquired in this aspect, no biological assemblage has yet been established for global stratigraphic correlations due to the coexistence of the two global biogeographic regions —— the Atlantic biogeographic region and the Indian-Pacific biogeographic region during the Early-Middle Cambrian. So, to develop and establish other approaches to the stratigraphic division and correlation of the Lower/Middle Cambrian on a global scale is a possible way to solve the puzzling problem. This work systematically studied acritarch fossils from the Early-Middle Cambrian Kaili Formation at Taijiang County, Guizhou Province. The Lower/Middle Cambrian boundary was divided in terms of acritarch fossil assemblage. The divided boundary is generally consistent with what was divided by trilobite and can be correlated with the Lower/Middle Cambrian boundaries divided by acritarch assemblage in Siberia and Europe. On this basis, the Lower/Middle Cambrian boundary is divided in terms of an obvious carbon isotopic excursion on a global scale during the transitional period from Early Cambrian to Middle Cambrian boundaries in Siberia and North America. The method for the stratigraphic division and correlation of the Lower/Middle Cambrian boundary in terms of carbon isotopic oscillations is helpful to solving the global problem on the division and correlation of the Lower/Middle Cambrian boundary. It is also evidenced that the extinction of a lot of trilobites at the end of Early Cambrian is closely related with this event of carbon isotopic excursion.

Equal channel angular deformation process and its neuro-simulation for fine-grained magnesium alloy

Fine-grained structure of as-cast magnesium AM60 alloy was obtained by means of equal channel angular deformation（ECAD） technique. Through analyzing the relationship between the load and the displacement under different working conditions, it is demonstrated that employment of back-pressure, multi-passages of deformation, and speed of deformation are the main factors representing ECAD working condition. As for ECAD process, a network composed of nonlinear neuro-element based on error back-propagation learning algorithm is launched to set up a processing mapping module for dynamic forecasting of load summit under different working conditions. The experimental results show that back-pressure, multi-passages and deforming speed have strong correlation with ECAD processing characteristics. On the metallographs of AM60 alloy after multi-passes ECAD, a morphology that inter-metallic compound Mg17Al12 precipites on magnesium matrix without discrepancy, which evolves from coarse casting ingot microstructure, is observed. And the grains are refined significantly under accumulated severe shear strain. The study demonstrates feasibility of ECAD by using as-cast magnesium alloy directly, and launches an intelligent neuro-simulation module for quantitative analysis of its process.