Study of red tide prediction model for the Changjiang Estuary

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Tests and applications of an approach to absorbing reflected waves towards incident boundary

If the upstream boundary conditions are prescribed based on the incident wave only, the time-dependent numerical models cannot effectively simulate the wave field when the physical or spurious reflected waves become significant. This paper describes carefully an approach to specifying the incident wave boundary conditions combined with a set sponge layer to absorb the reflected waves towards the incident boundary. Incorporated into a time-dependent numerical model, whose governing equations are the Boussinesq-type ones, the effectiveness of the approach is studied in detail. The general boundary conditions, describing the down-wave boundary conditions are also generalized to the case of random waves. The numerical model is in detail examined. The test cases include both the normal one-dimensional incident regular or random waves and the two-dimensional oblique incident regular waves. The calculated results show that the present approach is effective on damping the reflected waves towards the incident wave boundary.     

The Derivation and Validation of TBM Disc Cutter Wear Prediction Model

The problem of disc cutter wear is inevitable when shield or TBM excavating hard rock for a long distance, thus, the study of disc cutter wear model has an important project value on predicting its service life and replacement opportunity. It is put forward by analyzing disc cutter wear mechanism that the main wear form is abrasive wear, which is based on plastic removal mechanism. Then, disc cutter wear rate and linear wear rate prediction models are obtained by approximate calculation and mathematical deduction, which are based on Rabinowicz equation and CSM model. At last, the two models are verified through field test data from three projects, and the results show that the prediction model can accurately reflect the real wear situation of disc cutter.     

生物气CO2还原途径中碳同位素分馏作用研究及应用

地质历史中,CO2/H2还原产甲烷作用对生物气的形成具有十分重要的意义。中国柴达木盆地第四系生物气主要为CO2/H2还原型生物气。笔者以CO2/H2还原生气理论为指导,进行不同初始碳同位素值和不同赋存状态碳源的生物模拟实验,研究CO2/H2还原产气过程中发生的碳同位素分馏作用。实验结果表明,产物中δ13CH4值与底物的δ13C值呈很好的正相关关系;在反应母质过量的情况下,碳源的赋存状态可以影响产物甲烷的碳同位素组成。以游离形式CO2还原产生的甲烷δ13C值,相对于以HCO3-、CO23-离子形式产生的甲烷δ13C值轻。通过柴达木盆地东部第四系生物气田实例分析,探讨了该区生物气的主要底物CO2的来源及赋存状态,对评价盆地生物气资源和有利勘探区预测有重要的参考价值。     

国际南极大地参考框架的构建与进展

回顾了南极大地参考框架发展的历史,总结了由国际南极研究科学委员会(SCAR)组织的历次南极地区大地测量观测活动的成果,并结合2007~2008第四次国际极地年(IPY)对南极大地参考框架的前景进行了展望,其中重点介绍了我国对构建南极大地参考框架的贡献。     

The hydrothermal karstification and its effect on Ordovician carbonate reservoir in Tazhong uplift of Tarim Basin,Northwest China

With a detailed study on petrology, mineralogy and geochemistry of some important Ordovician carbonate well core samples in Tazhong uplift of Tarim Basin, the distinguishing symbols of hydrothermal karstification are first put forward as the phenomena of rock hot depigmentation, hot cataclasm and the appearance of typical hydrothermal minerals such as fluorite, barite, pyrite, quartz and sphalerite. The main homogenization temperatures of primary fluid inclusions in fluorite are from 260 to 310°C, indicating the temperature of hydrothermal fluid. The fluid affected the dissolved rocks and showed typical geochemistry features with low contents of Na and Mg, and high contents of Fe, Mn and Si. The ratio of ³He/⁴He is 0.02R _a, indicating the fluid from the typical continental crust. The hydrothermal fluid karstification pattern may be described as follows: the hot fluid is from the Permian magma, containing dissolving ingredients of CO₂ and H₂S, and shifts along fault, ruptures and unconformity, and dissolves the surrounding carbonates while it flows. The mechanism of hydrothermal karstification is that the mixture of two or more fluids, which have different ion intensity and pH values, becomes a new unsaturated fluid to carbonates. The hydrothermal karstification is an important process to form hypo-dissolved pinholes in Ordovician carbonates of Tazhong uplift of Tarim Basin, and the forming of hydrothermal minerals also has favorable influence on carbonate reservoirs.

     

Heavy-Rain expert-system realized by logical language prolog

This article, on the basis of the expert’s analyses and theories of the forecast of heavy-rain, summarizes a variety of the current instruments and methods of forecast and, according to the train of thought of the high-rank forecasters, distills their experiences in forecasting heavy-rain into an inference-tree of 106 junctures from which 101 rule-bases are derived. The logical calculation is automatically carried out with our introduced and developed PROLOG, one of the intelligent languagas by means of micro-computer. This process adopts the uncertain inferential method based on the theory of fuzzy sets, breaks through the limits of two-value logic and is characteristic of the thinking of human brain.     

有机显微组分X射线衍射分析方法在油气评价中的应用

Ｘ射线衍射分析法适宜于分析有机显微组分的芳环层的层状结构。有机质的芳环层结构与其类型和演化程度有关。表征有机质芳环层的层状结构的主要参数：高度Ｌｃ、宽度Ｌａ、网面间距ｄｈｋ１和芳环层层数可作为油气勘探中判断源岩性质、类型、演化程度与生烃潜力的依据。文章还对参数的变化与意义进行了初步讨论。