08 August 2011, Volume 29 Issue 22

    

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  Synthesis and Adsorption Process of Lithium Taking Used as High-Temperature CO₂ Sorbents

  WENG Duan;WAN Jie;RAN Rui

  . 2011, 29(22): 25-30. https://doi.org/10.3981/j.issn.1000-7857.2011.22.001

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  One of the high-temperature CO₂ sorbents lithium orthosilicates (Li₄SiO₄) was synthesized by using sol-gel method. The structures and the adsorption properties of Li₄SiO₄ were investigated by XRD, temperature-programming tests, and isothermal tests. In-situ FTIR tests were carried out to analyze the adsorption species and procedure. The results show that high purity (more than 90%) monoclinic Li₄SiO₄ could be obtained by adding citric acid into the LiNO₃-TEOs-Ethanol co-hydrolysis system. Such a Li₄SiO₄ material shows good CO₂ adsorption performance in the atmosphere of 2% CO₂ in He within the temperature range of 450-500℃. The major adsorption species on the surfaces of the samples are bicarbonates at lower adsorption temperature, and are ion-type carbonates and horizontal-type carbonates at higher temperature.
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  Community Structure of Rotifer and Water Quality Assessment in Dishui Lake River System of Shanghai

  JIANG Min;REN Zhi'an;XING Bin;LU Liu;HU Wenting;CHEN Lijing;LI Juanying

  . 2011, 29(22): 31-37. https://doi.org/10.3981/j.issn.1000-7857.2011.22.002

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  In order to understand the status of rotifer community and the relationship with water quality, the rotifer community and water quality status in Dishui Lake river system of Shanghai were monthly studied from January to December in 2010. There were six and five sampling points in the priming river course and the lake area, respectively. 35 species of rotifers belonging to 7 families and 19 genera were identified. The dominant species were Polyarthra trigla, Trichocerca pusilla, and Anuraeopsis fissa. The uniform annual values of rotifer density and biomass in the priming river course were 821.31/L and 600.97×10^-3mg/L, respectively; and the same values in the lake area were 434.98/L and 317.74×10^-3mg/L, respectively. Annual means of Margalef diversity index in the priming river course and the lake area were 1.87±0.19 and 1.14±0.23, respectively. Annual means of Shannon-Wiener diversity index in the priming river course and the lake area were 1.58±0.25 and 1.21±0.76, respectively. Density, biomass, and diversity index of rotifers in the priming river course were higher than that in the lake area. Seasonally, rotifer density was significantly positively correlated with the value BOD₅ and a most significantly positive correlation between rotifer biomass and BOD₅ was also detected in the priming river course. There was a significantly positive correlation between the rotifer density and water temperature in the lake area and the correlation between the biomass and water temperature was most significantly positive. Horizontally, the annual mean of rotifer biomass was significantly negatively correlated with the total dissolved salt and pH, while it was significantly positively correlated with NO₂-N, and also had a most significantly positive correlation with BOD₅. Water quality of Dishui Lake river system was evaluated considering indicator organisms, species diversity index, and physicochemical factors of the water. The results show that lake area is in the light eutrophication level and priming river course is in the light-middle eutrophication level in the year of 2010.
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  Molecular Phylogenetic Analysis of Holometabola Based on 18S rDNA

  REN Guodong;NING Jing

  . 2011, 29(22): 38-41. https://doi.org/10.3981/j.issn.1000-7857.2011.22.003

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  In order to reveal the phylogenetic relationships of Holometabola, the fragments of 18S rDNA gene of 21 species in 21 families of 11 orders from Holometabola and 3 species in 3 orders from Paraneoptera as outgroups are used in the current analysis. After the alignment of the sequences, the likelihood ratio test is carried out to find the best model of nucleotide substitution fitting the data obtained from the alignment. The molecular phylogenetic trees are reconstructed with ML and Bayesian methods. The hierarchical likelihood ratio test is used to analyze the dataset. The result suggests a division into three large clades comprising Diptera+Strepsiptera, Coleoptera+(Megaloptera+(Raphidioptera+Neuroptera)) and Hymenoptera+(Siphonaptera+Mecoptera)+(Lepidoptera+Trichoptera) in the cladogram of Endopterygota. Mecopterida is not a monophyly.
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  Influence of Fluid Boundary Layer on Fluid Flow in Low Permeability Oilfields

  LIU Weidong;LIU Ji;SUN Linghui;LI Yang;LAN Xiyan

  . 2011, 29(22): 42-44. https://doi.org/10.3981/j.issn.1000-7857.2011.22.004

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  A fluid boundary layer would impede the flow of fluid near the pore and the throat of the rock in the low-permeability reservoir because of the small size of pore-throat, the complex pore structures and the large solid-liquid interfacial force. In order to study the influence of the fluid boundary layer on the fluid flow in a low permeability reservoir, the relationships between the fluid flow rate, the boundary layer thickness and the pressure gradient are obtained through analysis and fitting data, based on the experimental results of deionized water flowing through microtubes of radii of 10.0, 7.5 and 5.0μm, respectively. It is indicated that, due to the existence of the fluid boundary layer, the flow of deionized water through microtubes with different radii deviates from the classical Darcy flow pattern and shows nonlinear characteristics with a threshold pressure gradient under low pressure conditions. The degree of deviation of the flow pattern from the law of Darcy flow increases and the nonlinearity of the flow becomes more significantly with the decrease of the tube diameter. The fluid boundary layer thickness decreases exponentially with the pressure gradient and tends to assume a stable value when the pressure gradient approaches a critical value. The formula for single-phase fluid seepaging in a low permeability reservoir is obtained based on the non-equivalent diameter capillary module.
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  Impact of Penetrant Solution Water Lock Effection on Gas Desorption

  ZHANG Guohua;LIANG Bing;HOU Fengcai;BI Yewu

  . 2011, 29(22): 45-50. https://doi.org/10.3981/j.issn.1000-7857.2011.22.005

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  For the question of gas exceeding limit on the coal face, the gas desorption experimental measuring device under external solution invasion is used; and the device is the result of independent research and development. Under the conditions of external solution invasion and no external solution invasion, gas desorption comparative experiments are carried out, the experiment data and curve of gas desorption are obtained, and the influence of external solution invasion upon gas desorption is analyzed. The results show that whether or not there is the external solution invasion, the higher gas pressure of coal with gas is, the larger gas natural desorption quantity is, and gas desorption is mainly concentrated on first 1h; after external solution invades, water lock effect on the coal with gas could be produced, therefore gas desorption quantity is reduced and gas release speed is slow down. Preventing gas from exceeding limit on a coal face by using water lock effect is feasible, it could be implemented through two solutions, that is, coal bed infuse solution and spraying permeable agent solution during the coal mining.
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  Exogenous Microbial Enhanced Water-Flooding Pilot Tests in China

  GUO Ying

  . 2011, 29(22): 51-54. https://doi.org/10.3981/j.issn.1000-7857.2011.22.006

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  In order to reduce the risk of the pilot tests in microbial enhanced oil recovery and to develop scientific procedures, the parameters of in-situ microbial enhanced oil recovery projects should be investigated, including injection volume, injection concentration, injection patterns and enhanced oil production. The current field application of exogenous microbial enhanced water-flooding is in a developing stage. The injection volume ranges from 0.002 to 0.007PV (Pore Volume). The average microbial concentration is between 1% and 3%. The main injection patterns are of multi-cycle injection and slug injection, with good performancel. However, there are still some issues that require further explorations. In view of the present domestic situation about exogenous microbial enhanced water-flooding pilot tests, the active bacteria are advised to be selected by using advanced microbial technologies and by developing cost-effective nutrient package. Moreover, for specific reservoirs to choose profile modification and water-flooding, throughput and water-flooding in combination, it is necessary to combine indigenous and exogenous microorganisms. The application of exogenous microbial enhanced water-flooding should be improved further by changing injection water and biological inhibition to keep the continuity of microbial enhanced oil recovery.
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  Numerical Simulation of Explosion Process due to LNG Leakage from Pipelines in Tunnel

  MA Shihai;HUANG Ping;DAI Pengfei;LI Xiang

  . 2011, 29(22): 55-57. https://doi.org/10.3981/j.issn.1000-7857.2011.22.007

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  In order to simulate the explosion process due to Liquefied Natural Gas(LNG) pipeline leakage in tunnel, a mathematical model of fire and explosion due to LNG pipeline leakage is proposed based on the Computational Fluid Dynamics (CFD) method and for an active LNG transportation pipeline in a tunnel. The LNG leakage explosion under three different LNG leakage conditions are numerically simulated, and their overpressures at the measuring points are obtained for tunnel with solid ends and pressure release ends. The explosion overpressures caused by LNG pipeline leakage under three different boundary conditions are obtained and the destruction effect is evaluated. The simulation results show that the explosion is in the form of deflagration when the LNG leakage intensity is the maximum or the minimum in the tunnel with solid ends or pressure release ends, which would damage badly the equipments in tunnel. When the LNG leakage intensity is a medium one, the deflagration would transform into the detonation with very strong damage power, and this should be avoided to be happening.
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  Experimental Investigation and Analysis on the Safe Distance of Propagation Blast for Industrial Detonators

  HOU Haizhou;HU Yiting;WEI Yan'an

  . 2011, 29(22): 58-60. https://doi.org/10.3981/j.issn.1000-7857.2011.22.008

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  The safe distance of propagation blast for industrial detonators is tested. The lift-descending method is used in the experiment. The safe distances of propagation blast for 100 DDNP primary explosive carton detonators, 100 DDNP primary explosive aluminum detonators, 100 non-primary explosive carton detonators, and 100 non-primary explosive carton detonators for mining use are obtained. For DDNP primary explosive detonators, the safe distance of propagation blast for aluminum detonator is greater than that for the cardboard detonator. The safe distance of propagation blast for DDNP primary explosive detonator is greater than that for non-primary explosive detonator. The safe distance of propagation blast for non-primary explosive carton detonator for mining use is less than that for non-primary explosive carton detonator. The overpressure measurement in the blast field of detonator is carried out. There is a major difference between calculated results for the pressure field with the experiment results for that. The reason for the difference is analyzed. The ability of detonator initiation is a complex issue. The experimental results indicate that the major factor of detonation for one detonator is the shock wave of the main detonator, however, for the 100 detonators, the shock wave and explosive gases sent by main detonators explosion are the direct cause for propagation blast by rest of detonators.
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  New Criteria for Oscillation of Nonlinear Impulsive Neutral Parabolic Equations

  LI Yuandan;GAO Zhenghui;PENG Baiyu

  . 2011, 29(22): 61-63. https://doi.org/10.3981/j.issn.1000-7857.2011.22.009

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  The oscillation of a class of nonlinear impulsive neutral parabolic differential equations with higher order Laplace operators is considered. By using the first order impulsive delay differential inequalities, some new sufficient conditions for oscillation of all solutions of the equations are established under the Robin boundary value condition. The results in this paper have generalized some existing conclusions.
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  Test of Concrete Strength of the Bridge Structure Based on the Gluing Pull-out Method

  LU Yigang;PENG Hui;TANG Teng;HUANG Hao;XU Kang

  . 2011, 29(22): 64-67. https://doi.org/10.3981/j.issn.1000-7857.2011.22.010

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  In the inspection of bridge structures, the use of the gluing pull-out method for the concrete strength can avoid not only the serious damage to the structures as would occur by using the structural damage detection method, but also the disadvantages of the conventional nondestructive methods, such as the rebound law, such as poor precision. In order to use the gluing pull-out method in the real structures more conveniently, an organic anchorage is employed as the anchoring gum and through comparison, a reusable tensile steel anchoring pull system is designed. The results show that better precision results can be obtained by using this method. Using the statistical analysis method and the least squares method for the pulling forces for a number of two-way reinforced concrete slab and for the corresponding compressive strength of concrete test cubes, the curves of strength against pulling force for the bridge structure are obtained. The results show that better correlations and smaller relative standard deviations can be achieved. The gluing pull-out method is also used in the field exposure tests of two prestressed concrete beams by using the strength curves. The results show that the calculated values are in good agreement with the experimental values.
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  Efficiency Evaluation of Two Combined Processes for Treating Tannery Wastewater

  LI Jianzheng;CHEN Qingsong;KE Weishi;LI Yao

  . 2011, 29(22): 68-71. https://doi.org/10.3981/j.issn.1000-7857.2011.22.011

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  Two processes used to treat organic wastewater discharged from a tannery are discussed and their treatment efficiencies are compared. The results show that the process of sequencing the batch reactor (SBR) combined with the contact oxidation (O-SBR) is more realistic than that of SBR combined with the hydrolysis acidification (H-SBR). With HRT contact oxidation for 24h and sewage aeration for 5-7h in the SBR, the average removal of 83% for COD and 74% for ammonia are achieved in the O-SBR process. The COD and ammonia in the effluent of the O-SBR process are about 273mg/L and 42mg/L, respectively. With HRT contact oxidation for 24h and the same sewage aeration in the SBR, the average removal of COD and ammonia are only 70% and 5%, respectively, in the H-SBR process. Though the COD is less than 500 mg/L, the ammonia is as high as 163mg/L in the effluent. Furthermore, an attached process to the H-SBR has to be constructed for fetor collection, transfer and treatment.
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  Characteristic Analysis of Radar Target with Micro-motions

  LIU Yongxiang;LI Kangle;LI Xiang;JIANG Weidong;ZHUANG Zhaowen

  . 2011, 29(22): 72-79. https://doi.org/10.3981/j.issn.1000-7857.2011.22.012

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  The analysis of radar targets in micro-motions is an emerging technical hotspot in the field of radar target acquisition and identification, and much progress has been made during this decade. Some scientific issues related to micro-motion analysis are discussed in this paper, such as the modulation in radar returns induced by micro-motions, the extraction of micro-motion features, the radar imaging for targets in micro-motions, and the radar waveform designing oriented to micro-motion features. Some of the research achievements have already applied in the fields of aerial and spatial target acquisition and identification.