28 June 2011, Volume 29 Issue 18
    

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    Articles
  • XUE Junzeng;XIAO Li;WU Huixian
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    Tetraclita japonica is a good bio-monitor for the marine heavy metal pollution. Tetraclita japonica is a fouling organism and commonly distributes in the rocky intertidal zone of Zhoushan Islands, which has high accumulation abilities of heavy metal. In order to investigate heavy metal pollution in Zhoushan sea area and its enrichment regularity in marine organisms, the accumulation abilities of Cu, Pb, Cd, Cr, As, and Hg in Tetraclita japonica are analyzed. The results show that content of Cu are much higher than that of Pb, Cd, Cr, As, and Hg in Tetraclita japonica, and there is also a significantly positive correlation between Pb and Hg content. According to its total quantity of accumulated metals, it could be seen that Tetraclita japonica from Daishan and Xiaoyang Islands are most severely polluted by heavy metal among the seven sampling sites studied. In comparison with the biological quality criteria for marine bivalves, metal contents in Tetraclita japonica are almost below the second standard value except contents of Pb and Hg. By contrast to the heavy metals of Cu, Cr, Cd, and As, Tetraclita japonica in Zhoushan Islands is contaminated by Pb and Hg quite seriously.
  • ZHANG Wenqi;WANG Zhizhang;HAN Haiying;CHEN Zhaoyou;LIU Zhongqun
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    In Daniudi gas field there are many gas bearing segments, and the sand bodies are highly heterogeneous with great lateral variations, so the differences of the wave impedance are indistinct. Based on the stratigraphic framework, the seismic waveform differences of the reservoir are analyzed according to the production information of wells. There are some differences in the center, probability, and characteristic value of centroid, mean, variance and varying variance for the seismic waves from nearby wells between different production layers, but the sensibility is not enough. In order to obtain seismic waveform parameters of gas bearing formation with higher sensitivity, the seismic waveform sensitive formation is analyzed and reconstructed, and seven waveform parameters are obtained. By analysis and reconstruction of the sensitive information, the corresponding relationship among reservoirs of different productivity and seismic waves is established, and the data of waveform differences are obtained by inversion for the target stratum with this relationship. Combined with geological information, sedimentary facies etc. the waveform difference data are interpreted, and the high gas area layer prediction diagram of the target stratum is obtained. With the data of production wells and new production wells in this area, the prediction results are analyzed, and the total prediction agreement rate reaches 86%.
  • LIU Wei;CHEN Jie;WAN Ce;WU Kongyou
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    Based on the characteristics of strata, tectonics, sedimentary reservoir and fluid characteristics, the dominant factors of the hydrocarbon accumulation in Qigu Formation in Zhong32 wellblock in Junggar Basin are analyzed from the aspects of unconformity and faulty. The results show that Qigu Formation reservoir belongs to the type that would exist in the semi-weathering rock of Cretaceous-Jurassic unconformity in a fault block background. The model of hydrocarbon pool-forming is a secondary reservoir controlled by unconformity-fault, out of the source rock province from the late Jurassic to the Cretaceous unconformity. The unconformity-fault system of migration and accumulation is the primary system in the hydrocarbon migration and accumulation. The long-term weathering and erosion makes the reservoir quality much better. Though the Weathered Clay of Cretaceous-Jurassic unconformity is widespread development in Zhong32 wellblock, its sealing ability is poor, resulting in the leakage of light weight fractions of hydrocarbon and the formation of heavy oil reservoirs. Multistage tectonization and unconformity-fault migration-accumulation system are the main controlling factors for super heavy oil reservoirs in Qigu Formation.
  • ZHOU Gaiying;LIU Xiangjun
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    The current evaluation and testing for tight sandstone reservoirs is not as satisfactory as for conventional sandstone, with a low well log interpretation coincidence rate. The fundamental reason is that the reservoir hydrocarbon saturation can not be determined accurately. The calculating methods for the conventional sandstone reservoir saturation are used for the tight sandstone reservoirs and the key of these methods is to obtain high-quality rock electrical parameters. The rock electric parameters for a tight sandstone reservoir are more difficult to obtain because of the small porosity and the complex pore structure, so one often uses the rock electric parameters of a reservoir of higher porosity and permeability in the same area. According to the characteristics of tight sandstone, the gas drive experiments were carried out to study the variations of electric parameters. It is found that a big difference exists in the b, n values between reservoirs of high porosity and permeability and tight sandstone reservoirs. The values of b, n vary in different ranges of water saturation of the cores of 5% to 10%porosity. Under a high water saturation, the value of b is nearly 1 and the value of n is within a range of 1.3 to 14.1; under a low water saturation, the value of b is within a range of 1.4 to 2.9, the value of n is within a range of 0.5 to 1.7. Since the water saturation is greater than 90% in the high water section, the selection of b, n values of low-water saturation should be careful in well log interpretion. With experimental results being used in a few wells, these results are shown to be consistent with the test results.
  • WEN Zhijie;XIA Hongchun;DONG Hongqing
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    Based on the ground pressure and strata control theory with "the strata movement and abutment pressure" as the core, the stope structural mechanical model and the gob-side retaining entry mechanical model are built, the caving zone height is determined, the non-compressed and compressed gangue deformation calculation formula is obtained, the compression effect of coal gangue in the mined-out area is explained and the gob-side retaining entry surrounding deformation is analyzed. For the coal gangue with three kinds of size ranks(10—20mm, 20—30mm, 30—60mm), their compression characteristics are analyzed by MTS 815.03 electron hydraulic servo machine and home-made compression testing-equipment, and its compression-time characteristics are obtained. The results show that the strata weight of the fracture-arch in the stope is the main source of the compression effect of the coal gangue in the mined-out area. The coal gangue deformation is about from beginning to the dense condition; the coal gangue compression curve assumes a logarithmic relationship; the test results agree well with the field data.
  • LI Congying;CAI Guanglin;ZHU Tong
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    In order to evaluate vehicle collision avoidance systems, and to optimize the warning algorithm, this paper proposes a serial of indexes, including the effective warning rate and the wrong warning rate. According to the actual road conditions, simulation scenarios and experimental procedures are designed, for the experimental group and the control group, with and without warning system. A simulation evaluation method is used to obtain the corresponding indexes. According to the method, a platform for the warning algorithm simulation evaluation is built by the secondary development of the microscopic traffic simulation software VISSIM based on Visual Basic 2005. Various functions are implemented, including the parameter input, the result output at the VB port, the simulation process control, and the automatic statistical analysis. Honda and PATH algorithms are evaluated on the platform. It is shown that the latter algorithm has a higher effective warning rate and lower wrong warning rate as compared with the former one. The evaluation results are consistent with other related studies, which shows that the method is an effective quantitative analysis evaluation method with a low cost for warning algorithms.
  • ZHANG Liang;GUO Yanfeng;HE Hua
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    The objective of the physical topology discovery is to determine the connection relationship between various equipments in the network and the link between physical ports, which is very important for maintenance work, and with which the performance of the network can be monitored and evaluated efficiently and the fault discovery and positioning is also made easy. This paper proposes an optimization algorithm based on the predicate logic reasoning and the spanning tree protocol. It can effectively compute node information under the circumstances that the topology discovery AFT(Address Forwarding Table) data are incomplete. Thus the algorithm can overcome the shortcomings of the existing link layer network topology discovery, to obtain a possible physical topology network. This paper provides a new way to discovery link layer topology, with the link deducation technology, "to repair and revise" the uncomplete root AFT data. The shortcomings of the predicate logic and STP(Spanning Tree Protocol) algorithm are remedied, and the advantages are taken.
  • ZENG Fanhui;CAO Jun
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    In this paper, the structured element theory is introduced into the fuzzy multi-attribute decision making. The fuzzy number space and the family of standard bounded monotone functions have the homeomorphic property. Based on this feature, complex operations of fuzzy numbers are put into monotone functions with the same monotonic format. The order relation of monotone functions is used to describe that of fuzzy numbers. The aim is to simplify the complex operations of the traditional fuzzy decision making. The classic ELECTRE method is extended into the fuzzy environment and is combined with the fuzzy structured element. The fuzzy multi-attribute decision making problem is thus solved. It overcomes some shortcomings. For example, the classic ELECTRE method is diffcult to rank fuzzy numbers and has to be turned into a deterministic system. This new method is based on the fuzzy structured element, is simple to operate and easy to understand. It can be used for further study of fuzzy multi-attribute group decision making. An example shows the effectiveness and feasibility of this method.
  • ZHANG Huasheng
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    As a well-known semigroup, Hamilton semigroup acts on continuous functions in an algebra system. According to the characteristics of Hamilton semigroup, some basic properties of the semigroup and graph theoretical representation are used to investigate the structure of endomorphism to Hamilton semigroup. First of all, a new multiplication, which can solve the problem with computing endomorphism for Hamilton semigroup, is defined and then the main result that the endomorphism of Hamilton semigroup is also a Hamilton semigroup is given. Moreover, by adopting the partial order to the endomorphism of Hamilton semigroup, an expression of graph theory is established and that the Hasse graph for endomorphism semigroup is an oriented forest is proved.
  • LI Fengsen;GAO Zhen;JING Jing;XU Dan;YANG Jian;UPUR Halmurat;
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    By measuring the contents of inflammatory cytokines IL-1β, IL-8, IL-10 and TNF-α in peripheral area of cold dry syndrome of Chronic Obstructive Pulmonary Disease (COPD) model, the cold dry syndrome of the COPD model of systemic inflammatory response is characterized. The COPD model is established by combined cigarette smoke and tracheal instillation of elastase, and in pulse cold and dry environment, the cold dry syndrome of COPD is established. The Enzyme-Linked Immunosorbent Assay (ELISA) method is used to measure the blood serum of IL-1β, IL-8, IL-10 and TNF-α. The results show that in the serum, the cold and dry environment plus CS plus racheal instillation of elastase group makes the IL-1β content higher than that in the control group (P<0.05); IL-8, IL-10 and TNF-α are in higher levels than in the control group, in general, but not with a significant difference between the three groups. So it may be concluded that the cold dry syndrome (cold and dry environment) leads to the systemic inflammatory response primarily due to the increase of IL-1β; the cold dry syndrome may increase the systemic inflammation level in COPD in some extent; in different areas, different treatments should be used; the cold dry syndrome takes part in COPD, but it does not belong to the heavy type of COPD, and, of course, it should be controlled and prevented.
  • Reviews
  • XIAO Chunhua;GUI Yewei;LIN Guiping
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    Aircraft might experience icing when passing through icing clouds containing supercooled water droplets. Ice accretion is one of primary hazards to the flight safety, which would deteriorate aircraft aerodynamics characteristics to affect the flight safety. It is important to remove ice on the aircraft. Electrothermal de-icing is one of the most widely applied techniques for aircraft de-icing. This paper discusses the method and the working principle of electrothermal de-icing equipment. Firstly, the studies of electrothermal de-icing are reviewed, including those related with heat transfer and mechaniccal characteristics and ice ridge formation during aircraft electrothermal de-icing process. Secondly, some practical issues about electrothermal de-icing are discussed, including numerical simulations, electrothermal de-icing techniques, effects of coupled thermo-mechanical characteristics on melting and mechanical characteristics, ice shedding and movement.
  • LI Juan;LI Shunxiang;;HUANG Dan;ZHAO Xingbing;CAI Guangxian;
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    Dendrobium officinale is a valuable medicinal plant, and is widely used in the treatment and daily health care, however, the lack of wild resources and expensive price lead to market disruption of Dendrobium officinale. With the maturation of artificial cultivation technology, the problem related to the lack of resources is gradually solved in recent years. Its tissue culture, cultivation, quality control, chemical constituents, pharmacology and clinical applications, etc are studied at home and aboard. Resources of Dendrobium officinale in term of the Latin name, morphological characteristics, commodity, quality evaluation, and genetic diversity are comprehensively summarized, chemical constituents in polysaccharides, amino acids, trace elements, phenanthrenes, bibenzyls, phenolic acids, and alkaloids are reviewed, and pharmacological effects for improving immune functioning, anti-tumor, anti-aging, lowering blood glucose and blood pressure are integrated. A scientific and theoretical foundation for studying constituents and biological activities of Dendrobium officinale, and for further developing medicinal value of natural products is provided.