28 January 2011, Volume 29 Issue 11-03
    

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  • Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Based on the event every year for selecting the annual important advances about science, technology and engineering held by our publishing house, with the same principles of evaluating within each branch, putting quality before quantity, and giving facts in time order, 10 important scientific achievements, 10 important technological achievements and 10 important engineering achievements in China in 2010 were selected from a lot of scientific news in the columns Half-month News Index, Half-month News Briefs, News Round, Domestic Journal Highlights, Scientific Community Briefs, Scientific Events and Cover Stories in Science and Technology Review, and key academic journals and scientific newspapers. These achievements were introduced by the Editorial Department of Science and Technology Review Publishing House in this paper.
  • Articles
  • Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    In order to study the feasibility of enhancing oil recovery rate in Qinghai oil field with hypersalinity, the composition of indigenous microorganism community was analyzed by MPN counts, the nutrient packages for emulsification were evaluated, the acid production was studied and the sequence of 16S rDNA and the saturated hydrocarbon of oil samples were analyzed. Results show that the main microbial populations in the reservoir are saprophytic bacteria, hydrocarbon-oxidizing bacteria, fermentative bacteria and nitrate reducing bacteria. The indigenous microorganisms can use nutrition added for emulsification through acid production; its cell concentration can reach 107cells/mL, and the surface tension is reduced from 57.44mN/m to 38.5mN/m. The pH value of the fermentation liquor with nitrogen source is decreased from 7.19 to 6.56, and the pH value of the fermentation liquor added with carbon and phosphorous source remains unchanged, so the optimal nutrient was the nitrogen source (0.1% yeast and 0.1% peptone), which was used for all subsequent experiments. The total DNA was extracted, 16S rDNA universal primers were applied for gene amplification, and the results were sequenced and analyzed. The species isolated were confirmed to be Bacillus sp. and Halomonas sp.; the saturated hydrocarbon was catalyzed selectively (C11~C20, C28, C33), which exhibited a great potential to enhance oil recovery rate.
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    The reservoir classification and evaluation is an important topic of study, and in order to make reservoir classification more accurate and reasonable, in this paper, the method of Q cluster analysis combined with Bayesian discrimination algorithm is adopted. First, various reservoir parameters are optimized globally, including sandstone thickness, porosity, permeability, carbonate content, shale content and others, with the mathematical statistics method to assemble the parameters, and the algorithm of Q cluster analysis to do the reservoir classification. On this basis, Bayesian discrimination algorithm is adopted to establish the discriminant relationship between reservoir parameters and reservoir classification and evaluation, together with the discriminant function of reservoir classification and evaluation, based on which, the target beds of non-coring wells are classified and evaluated. Examples show that the method of Q cluster analysis combined with Bayes discrimination algorithm is effective to achieve reservoir classification and evaluation.
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    Paleoporosity and its evolution of sandstone reservoir is a hard and key task for studying the mechanism of hydrocarbon accumulation. Current methodology has some limitations. It can not take all controlling factors into consideration, the application process is too complicated, the precision of result is low and it can not embody the whole process of porosity evolution. Based on the project which studies on the mechanism of hydrocarbon accumulation within Chang Formation in Zhenjing area of Ordos Basin, a newly methodology to restore the paleoporosiy of sandstone is presented. This methodology is based on diagenetic history of strata and takes constructive and deconstructive diagenesis of porosity into account. With the effect-oriented simulation as the principle, the simulation process is divided into porosity decrease process and increase process. With the geological time as variable and constrained by the current porosity, the model demonstrates dynamic and reliable characteristics. The application of this methodology to Zhejing Area indicates that the evolution of the sandstone porosity is controlled by structure and sedimentary facies, and the distributary channel sandbodies along the up-lip direction of the monocline is the favorable location for the high-quality reservoirs. The process of porosity evolution of sandstone is a key control factor for a high-production hydrocarbon accumulation.
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    The cracks not only serve as the major reservoir space, but also as the important fluid flow channel in deep buried carbonate fractured reservoirs, and the development of fractures controls the scale of reservoirs and the productivity of a single well directly. Such reservoir features deep buried depth and complicated distribution of fractures due to the reformation of reservoirs. The crack identification, fracture prediction, and fracture characterization are very difficult. In this paper, a modeling method of carbonate fractured reservoir based on the marked point process simulation theory is proposed. The fracture density distribution model is established through the single-well data interpolation under volume constraints with attribute of ants. Taking the fractured reservoirs in Tahe X area as an example, a discrete fracture network is built with fracture occurrence statistical data and fracture density distribution model constraints. The discrete fracture network modeling can be intuitively reflect the fracture's space form and structure, to provide an effective geological model for the research of connectivity, heterogeneity, and percolation characteristics of the fractured system. This method can be used in reservoir modeling and development of carbonate fractured reservoirs.
  • YAN Bingbing;XIE Mingqiang;SUN Hongqi
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    The dynamics model of 3-UPS parallel mechanism with three degrees of freedom is created in order to determine the moving relations of the wriggle turning joints for a move-in-mud robot. After reviewed some relative researches on move-in-mud robot, a parallel mechanism with three degrees of freedom is given which can accomplish straight and turning movement. Based on the analysis on the moving characteristics of 3-UPS parallel mechanism, the kinematics model of this mechanism is created firstly, so as to obtain the relational expression of velocity and acceleration of moving platform and each branch chain. Then, based on the Lagrange equation, the dynamics model of 3-UPS parallel mechanism is established to solve the total driving force and torque of the whole system and the drive force of each active lever. By using software of Matlab, the simulation analysis on the dynamics model as mentioned above is carried out to get some changing curves about drive force and torque. These works provide the foundation for the design of control system of move-in-mud robot and give a reference to the dynamics analysis of parallel mechanism with few degrees of freedom.
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    Insufficient driving force is one of malfunctions that frequently occurs for engines, Due to complicated causes and overloading conditions, it is a difficult point in engine malfunction diagnoses. Based on the engine control principle, from a new visual angle, four kinds of causes of insufficient engine driving force are discussed, the variations of mixture characteristic values and the ignition angles in the fault conditions are obtained, together with a relationship among five parameters in fault conditions, including the injection time of each turn, which increases the correlation of these parameters greatly, and enhances their applicability in fault diagnosis. Based on this method, the locations may be identified where failure may occur.
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    In the lane change decision-making stage, scratch and rear-end accidents may occur owing to drivers' miss judgments on the relative distances and velocities. In order to clarify the formation mechanism of drivers' decision making and traffic conflict in the lane change process, based on the motion relationship of related vehicles and driving expectation, the boundary conditions are limited, and a lane change game concept is put forward. The finite and zero-sum grey game model with mixed strategies is introduced, and the model algorithm is subsequently derived. Strategy selection and income characteristics of the drivers in the game are researched by sample selection and data processing analysis under the condition of real-world experiments. Analysis shows that when the traffic conflict between lane change object vehicle and following vehicle in the target lane is inevitably, the ideal and optimal strategy for the object vehicle is slowing down and waiting, while corresponding strategy for the game opponent is passing by the critical conflict point with an acceleration, so as to give the consideration to driving safety and traveling time, then achieve the goal of global optimality. The results may give corresponding theoretical support to the formation mechanism of the traffic conflicts and allocation of right-of-way in a lane change process.
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    The water resources in China are becoming more and more a critical issue. New technologies for water purification are urgently required. Magnetic seeds are the key materials for treating wastewater containing non-ferromagnetic pollutants with the methods of superconducting magnetic separation . In this work, Fe3O4 nanoparticles were prepared by the co-precipitation method. In order to obtain cellulose assembled or Polyvinyl acetate (PVA) coated magnetic seeds, the nanoparticles were modified by chemical implantation or plasma surface polymerization methods on the surface. Microstructure analyses by X-ray diffraction(XRD) and Transmission Electron Microscope(TEM) and IR (Infrared spectrum) indicate that the absorptive groups can combine well with the magnetic particles. With respect to the magnetic properties of modified magnetic seeds and its absorbing dynamics for aqueous ions and organics, it is shown that both magnetic seeds enjoy over 90% of absorption rate, which can meet the demand of superconducting magnetic wastewater separation.
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    The possible mechanism of Uighur medicine Abnormal Savda Munzip (ASM) on the anti-tumor effects and its influence on tumor cell migration are explored. MTT was applied to determine the cell proliferation of human hepatoma (Bel-7402), human breast carcinoma (BCAP), human cervical cancer (Hela), and human gastric cancer proliferation (BGC-823) after treated with different concentration of ASM (1, 2.5, 5, 10, 20, 50mg/mL) for 48h; Human hepatoma cell line (Bel-7402) was selected for the cell motility study, the cell migration influence on human hepatoma (Bel-7402) were assessed by the wound-healing assay and the Scanning Electron Microscopy (SEM) technique after treated with ASM (5, 10, 20, 50mg/mL) for 48h. ASM produced the cytotoxinic effect on these four type of tumor cells in vitro and all type cells showed the obviously vitro inhibition after treated with ASM (15, 20mg/mL), there were difference inhibited effect among the four type of tumor cells, the results of wound-healing assay with SEM show that the moving ability of Bel-7402 treated with ASM has decreased. It is deduced that ASM might inhibit the ability of proliferation and moving of tumor cell.
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    Yangshan port is a China's major port and is building into an international shipping center. Docking of foreign vessels puts the Yangshan Port in a high risk of biological invasion. At the same time, the attachment of the fouling organisms in large numbers seriously affects the port facilities. In order to explore the diversity condition and development trend of fouling organisms in Yangshan Port, the community structure and the diversity of fouling organisms were studied by an asystematic scheme of quantitative quadrat sampling in different intertidal areas of Yangshan Port on May 2010. 17 species of fouling organisms were sampled. The dominant species were Amphibalanus reticulates and Ostrea cucullata. Density, biomass, community structure and diversity see significant difference in different intertidal areas. Species richness, density and biomass show an increasing tendency with the rising of the intertidal area. However, the evenness shows a decreasing tendency. The biodiversity index varies in the following manner: middle tidal zone>low tidal zone>high tidal zone. The coverage data of live fouling organisms in Yangshan Island are obtained. It is shown that the highest diversity occurs at the coverage of 30%~40% range of fouling organisms, and this result supports the intermediate disturbance hypothesis in all three diversity indices. Coverage is the basic parameter widely available for most observations or monitoring programs. The good qualitative characteristics of coverage provide a powerful tool for theoretical, experimental and modeling studies of fouling organisms in response to the disturbance.
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    It has been an interesting topic using energy beet to ferment ethanol. Because temperature would affect ethanol fermentation of energy beet greatly, in order to explore the adaptability to high temperature of the different strains and to screen better yeast to ferment in the high temperature, in this study, at first, by the single factor, temperature, the yeast HADY was screened to be tolerant to high temperature, such that when the fermentation temperature was 45℃, the translation rate of ethanol was 81.68%. However, the translation rate of ethanol of ADY was the highest at 31°C. Secondly, three main factors were screened out from nine factors related to fermentation by Plackett-Burman design and response surface methodology, including substrate concentration, ratio of solvent to material, added HADY amount, nutrient salts, phosphorus addition amount, pH value, rotational speed, fermentation temperature and fermentation time. The three main factors are substrate concentration, fermentation temperature and phosphorus addition amount. The optimized technological parameters of HADY are as follows: substrate concentration (mass fraction) 12%, mass ratio of solvent to material 1:1, added HADY 15%, nutrient salts 0.5, added phosphorus 0.9%, pH 5.0, rotation speed 130r/min, fermentation temperature 37℃ and fermentation time 44 hours. It is shown that the translation rate of ethanol is 89.43%.
  • Reviews
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    Basic principle of anaerobic digestion is simply reviewed. It includes anaerobic digestion theory and the main influencing factors. The development history of anaerobic digesters is summarized, and the characters, the running mechanisms, and application of some typically high-load reactors, such as Upflow Anaerobic Sludge Blanket (UASB), anaerobic expanded granular sludge bed and IC anaerobic reactor, are especially introduced. In summing up, the problems and the defects of the high-load anaerobic reactors are put forward. Finally, it is also pointed out that the future study of anaerobic digester should focus on how to raise the reactors' efficiency.