08 May 2011, Volume 29 Issue 13

    

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  Earthquake Occurrence Corretated with the Movement of the Sun and the Moon

  ZHAO Shuxian;XU Shaoxie;WU Pingjing;MA Li

  . 2011, 29(13): 18-23. https://doi.org/10.3981/j.issn.1000-7857.2011.13.001

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  Based on the data of global scale large earthquakes(M≥7.8) during the solar active cycles 23-24, and the data associated with Wenchuan aftershocks and Chile aftershocks, it has been found that there is a relationships between earthquakes occurrence and positions of the Sun and the Moon, and there is a relationship between earthquakes occurrence and main directions of solar wind magnetic field before earthquakes. These facts indicate that earthquake occurrence is related with the movement of the Sun and the Moon. Two kinds of earthquake events are studied. One is aftershocks including Wenchuan (2008-05-12 M8.0) aftershocks (M≥5.0) and Chile (2010-02-27 M 8.8) aftershocks (M≥5.5). Another is global scale large earthquakes (in the period of 1997-2010, M≥7.8). Even though numbers of earthquake event cases used are not very large, considering the fact that these earthquakes represent two very different kind of typical earthquakes and the magnitude and space of those events have a sufficient span, the results provided in here should possess universality. Stochastic probabilities of those results are less than 10^-4 to 10^-6; it is shown that the mechanism of earthquakes should be related to the movement of the Sun and the Moon. This is reason why much attention is paid to the universal condition of earthquake.
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  Unseating Prevention Devices Under the Excitation of Earthquake Sequence

  FANG Lei;ZHANG Yumin

  . 2011, 29(13): 24-28. https://doi.org/10.3981/j.issn.1000-7857.2011.13.002

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  Earthquake load has the character of random. The uses of anti-seismic measures have been proved to be effective on the reduction of bridge seismic damage when the bridges encounter with rare earthquake or unexpected earthquake. Unseating prevention devices are the ultimate security installment in the collapse-proof system, which used to protect the substructure falling down from piers as the supports lose their effectiveness. Based on relational design standards at home and abroad, time-history analysis has been conducted on the structure with cable-unseating prevention devices under rare earthquake and strong earthquake sequence. The variation laws involving the collapse-proof result of unseating prevention devices and effect of collapse-proof changing with both cable length and designed value for displacement have been obtained. Under rare earthquake, the rational unseating prevention devices could provide the ultimate security to the structure, increase the integrity and anti-pushing rigidity of the structure, and make the seismic load to be well-distributed among the piers. The unseating prevention devices are able to provide the ultimate security for the damaging structure under the strong earthquake sequence; and achieve the request that there is no collapse when strong earthquake occurs.
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  Energy and Sensitivity Evaluation of Explosives and Their Applications Based on Maximum Entropy Theory

  WANG Yu;FENG Shunshan

  . 2011, 29(13): 29-32. https://doi.org/10.3981/j.issn.1000-7857.2011.13.003

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  Energy and sensitivity are important performances of explosive which need to be carefully studied and accurately measured; therefore an energy and sensitivity evaluation method of explosives based on maximum entropy theory is created. The information related to energy and sensitivity of explosives is collected with statistical method and the entropy is calculated, the maximum entropy explosive is made as the most balanced one. The evaluation results indicate that the insensitive explosives are more balance than the energetic explosives in evaluation objects, the relationship between energy and safety of explosive is deduced from the evaluation results. The evaluation method is applied to formulation design in order to get the explosive formulation that is more balance in term of these two performances, the results show that NQ can become a good insensitizer for RDX and HMX. At last, a sample of RDX/NQ/TNT-25.5/34.5/40 formulation is prepared and the detonation velocity and rifle shooting sensitivity are tested, experimental results indicate that sample's detonation velocity only reduces a little bit however it is much more insensitive compared with TNT/RDX explosives, it is proved that the proposed formulation design method is feasible.
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  Biodegradation of Parathion in Soil by Acinetobacter sp. D10

  JIANG Li;SHI Yanfang;LIU Xin;LI Zhiming;ZHANG Xueyu;JIANG Binhui

  . 2011, 29(13): 33-39. https://doi.org/10.3891/j.issn.1000-7857.2011.13.004

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  Organophosphorus pesticides are worldwide widely used to control agricultural and household pests. Overall, organophosphorus compounds account for the 38% of total pesticides used globally. Parathion is a virulent organophosphate insecticide with perfect insecticidal efficiency. However, it is also highly toxic and harmful to human and other creatures. In order to investigate microbial remediation of soil polluted by pesticides, a strain D10 of parathion-degrading is obtained by selective enrichment culture from the pesticides-contaminated soil. Parathion could be used by D10 as a sole carbon source. D10 is identified as Acinetobacter sp. based on the morphological, physiochemical characters and 16S rDNA sequence analyses. The optimal growth temperature for D10 in shaking flasks is 28℃, and the optimal pH is 6.0—7.0. The optimal carbon and nitrogen source are sodium citrate and yeast powder, respectively. D10 grows fast and reaches at the maximum biomass after 24 hours incubation in nutrient medium. The D10-degradation rate of parathion is determined by using the Gas Chromatography(GC), and is 83.1% after 24 hours. The bio-degradation rate of parathion in simulated and sterilized contamination soils with 100 mg·kg^-1 parathion concentration reaches at 66.7% after seven days inoculation. The result shows that the D10 has a great practical value in the remediation of contaminated soils by parathion.
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  Changes of Surface Soil Organic Carbon in Different Degradation Succession Stages of Grassland Ecosystem in the Western Part of Jilin Province

  HAN Weizheng;TANG Jie;LI Zhaoyang;LI Na;LIU Sen

  . 2011, 29(13): 40-43. https://doi.org/10.3981/j.issn.1000-7857.2011.13.005

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  Grassland degradation is one of the major ecological problems in the western part of Jilin Province; grassland degradation changes the carbon balance of grassland ecosystem. By taking different succession stages of grassland degradation in the western part of Jilin Province as the research object, 40 sample plots were selected, and 160 soil samples were collected for further experimental analysis via wild plots investigation in Jiangjiadian of Da'an City. The following results are achieved through determining soil characteristic and investigating vegetation community. As converse succession is on the way, the water ratio of soil and coverage is decreasing, soil permeability is worse while vegetation biomass and biology diversity first go up and then fall. In different stage of degradation succession, organic carbon density in 40cm soil is increased from 47.72 t/hm² in Leymus chinense to 48.46 t/hm² in Carex duiuscula, and then the density is cutting down to 27.44 t/hm² in salt flat. Converse succession caused by grassland degradation made the organic carbon density in surface soil (0—40cm) decrease 8.45, 5.72, 3.68, and 1.74t/hm², respectively. The conclusions are listed as follows: Grassland degradation causes the large influence of organic carbon on surface soil, meanwhile has little influence on deep soil. It is not a simple carbon exposed process. Certain grassland degradation might increase the carbon reserves caused by artificial or natural impacts, while excessive degradation could accelerate the loss of grassland carbon store.
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  Study on the Sedimentary Microfacies Based on Medium Term Base-level Cycle Change: A Case of the Q4 Member in Fuyu Oilfield, Songliao Basin

  MEI Junwei;PENG Shimi;YUAN Xintao;ZHAO Jiahong

  . 2011, 29(13): 44-51. https://doi.org/10.3981/j.issn.1000-7857.2011.13.006

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  Based on the regional sedimentary background and the core and logging data, and from an analysis of its facies markers, such as rock type, granularity distribution, sedimentary structure, mudstone's colors and geochemical features, Q4 Member in Fuyu Oilfield, Songliao Basin is identified as in a deltaic deposition which includes delta plain and delta front. The delta plan is composed of branch channel, crevasse splay, natural levee, abandoned channel, and so on. The delta front is composed of underwater distributary channel, mouth bar, distal bar, underwater nature levee, and so on. The genetic type and the development model of sedimentary facies are closely related to the stratigraphic framework. Under the control of the medium-term base level cycle, the quantitatively identified graphic tablet of microfacies is established, based on the application of coring wells. The sedimentary facies of non-coring wells are quantitatively identified and finely classified under the guidance of the identified graphic tablet. According to the analysis results of the sedimentary microfacies, the planar and sectional distribution maps are obtained. The laws of microfacies distribution on the plane and in the vertical direction are analyzed. In order to reveal the relationship between sedimentary microfacies and the oil，the control effects of sediments on oil are further discussed. It is shown that the channel sand bodies have the best performance in development size, continuity, reservoir quality and oiliness, followed by the mouth bar sand bodies. These results can be used for further oilfield production adjustment and development.
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  Simulation of Hydrocarbon Generation History of Source Rocks in Laizhouwan Sag

  JIANG Lina.

  . 2011, 29(13): 52-56. https://doi.org/10.3981/j.issn.1000-7857.2011.13.007

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  In this paper, the IES basin modeling method and the model of Easy%R_o are firstly used to analyze the single well thermal history and the hydrocarbon generation history. The third member of Shahejie Formation (Es₃) and the fourth member of Shahejie Formation (Es₄) are the major source rocks in Laizhouwan Sag. Based on the study of the single well thermal history and the hydrocarbon generation history, the hydrocarbon states of the two major source rocks in different periods and different areas are discussed. It is shown that the 5.1Ma before the third member of Shahejie Formation (Es₃m) source rock goes already at the top oil window and the fourth member of Shahejie Formation source rock is in the stage of the hydrocarbon generation and is discharged into the northern sag. Now the two major source rocks are both in the stage of the hydrocarbon generation and are discharge into the northern sag and the fourth member of Shahejie Formation source rock is at the hydrocarbon peak in the center of the Northern sag.
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  Sensitivity Analysis on Computational Fluid Dynamics Modeling of Gas Dispersion

  ZHANG Bo;CHEN Guoming;

  . 2011, 29(13): 57-61. https://doi.org/10.3891/j.issn.1000-7857.2011.13.008

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  The definition of sensitivity analysis on Computational Fluid Dynamics (CFD) modeling for gas dispersion has been presented. It is an uncertainty analysis method during the modeling process which firstly identifies the most sensitive ones from a number of uncertain factors, and then monitors and analyzes their impacts on the simulation results, and lastly selects the most suitable modeling parameters. The advised orders for the analysis should be grid dependency, boundary conditions, turbulence models, and parameter analysis for solution controls, successively. The analysis theories and methods for two key factors including grid dependency and turbulence model sensitivity have been discussed. A case study of gas dispersion in a station for high sulfide hydrogen natural gas gathering has also been carried out. The results show that grid dependency analysis could obtain a balance point between model prediction accuracy and computation cost; most suitable turbulence description method could be selected by means of comparison between the prediction results made by both turbulence models and empirical formulas. Sensitivity analysis is important for establishing proper computation models, enhancing prediction accuracy, and reducing computation costs, and it is an indispensable step for gas dispersion CFD modeling.
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  Determination of Molecular Weight and K, α Values for Polymers of Glycidyl Methacrylate

  LIU Dengfeng;FU Ying

  . 2011, 29(13): 62-65. https://doi.org/10.3981/j.issn.1000-7857.2011.13.009

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  Polymers of Glycidyl Methacrylate (PGMA) were prepared by using dicumyl peroxide (DCP) as initiator at 160℃, then they were characterized by infrared spectroscope (FT-IR) and thermal gravimetric analysis (TGA). The average molecular weight of PGMA was determined with gel permeation chromatograph (GPC), the intrinsic viscosity of three PGMA with different amounts of DCP was measured with viscosimetry, then K and α values in Mark-Houwink equation of polymers were determined. The experimental results show that PGMA of a large molecular weight was formed during the course of GMA polymerization via heat initiation, and the polymerization degree of GMA was declined because of addition of DCP. The K and α values of PGMA solution were determined to be K=9.1×10^-4mL/g,α=0.87, which indicates that the molecular chain of GMA is in a stretched state in acetone.
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  Comparative Analysis on Two Heavy Snowfalls in the Winter of 2010—2011 in Zhejiang Province

  QIAN Zhuolei;ZHANG Jianhai

  . 2011, 29(13): 66-74. https://doi.org/10.3981/j.issn.1000-7857.2011.13.010

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  Using the NCEP/NCAR 1°×1° grid data, two of the heavy snowfall occurred in the winter of 2010—2011 in Zhejiang Province were studied. Based on the diagnostic analysis on the circulation over the high and low level, the moisture conditions, the dynamic field and the thermal characteristics and the comparison of the two heavy snowfall, the results indicate that the snowfall on December 15, 2010 was a cooling process with the erection transfer of high-altitude horizontal groove and strong surface cold air blowing southward, meanwhile the snowfall on January 18—21, 2011 was in the cool context with southern branch trough deepening and moving eastward and the warm-wet southwest wind blowing northward, the ground was within the control of cold high variability. At the middle level, for both cases, the augment of the southwester flow exists. Over the low-level, the former water vapor was transported by east jet, while the later water vapor was transported by the southwest air. The two processes require adequate supply of water vapor and vertical ascending motion. Energy front of the former is the southward, while the energy front of latter is a north-south fluctuation. Two processes both meet the basic conditions of temperature field and have the structure of a temperature inversion. However, the former has a strong inversion layer, while the latter is relatively shallow.
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  CO₂ Flooding Enhanced Oil Recovery Technique and Its Application Status

  ZHANG Deping

  . 2011, 29(13): 75-79. https://doi.org/10.3981/j.issn.1000-7857.2011.13.011

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  The global warming is accelerating due to huge amount of greenhouse gas emission of CO₂ which leads to the temperature rise and the climate change on the earth. Global warming has put much pressure on both human being survival and social economy development. The most effective way for disposing CO₂ is to directly inject them into oil and gas fields, and only in this way, not only CO₂ could be sealed up but also the recovery rate of oil and gas fields could be enhanced. CO₂ flooding Enhanced Oil Recovery (EOR) technique has been widely applied to the low permeability reservoirs all over the world. Against the status that Chinese natural capacity of low permeability reservoir is low, carbon dioxide miscible and non-miscible flooding mechanism of EOR, and corresponding screening criteria, the research status are systematically discussed in here. According to actual application analysis of carbon dioxide to enhance oil recovery in low permeability reservoir at home and abroad, it is put forward that carbon dioxide could increase oil and decrease water, and effectively enhance oil recovery, and the main problems needed to be solved are summarized. In addition, the suggestions on actively developing carbon dioxide technique research and on-site test are offered. Finally, the development prospect of EOR is looked ahead.