08 March 2012, Volume 30 Issue 7

    

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  A Lattice Model for the Evolution of River Networks

  HAO Rui;FENG Guolin;HUO Jie;WANG Xuming

  . 2012, 30(7): 18-22. https://doi.org/10.3981/j.issn.1000-7857.2012.07.002

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  Usually, river patterns are greatly related to the natural factors, such as water erosion, landform, etc. Based on water erosion mechanism and original landform, a lattice model for river networks is proposed in order to simulate the growth process and to understand the selection of the nature, namely, fractal structure and scaling behaviors. The lattice is located at an inclined plane with fluctuant surface. The edges of the lattice are the possible water route. The selection of water route is dominated by the order of nature, that is, water flows downwards. A lattice point might be a "lake point", since its altitude is less than that of all the nearest neighbors. A steady river network might be set up as soon as all of the lake points disappear. Meanwhile, the scaling relationships dominating the fractal structure might be established. The statistical results on the landscape of the surface and the network connected by the water routes which actually mimic the river channels follow the Horton's laws. The laws suggest that the ratio of the average stream lengths of rank ω+1 to those of rank ω has a fixed value that is independent of ω. The same statements also hold for the ratios of average stream numbers and basin areas. The results show that the cumulative probabilities for the both stream lengths and basin areas conform to the power law distributions. These are in accord with those observed in the real river networks. These power laws indicate that there is no any characteristic scale in a river network. The spirit of the model shows that the dynamical origin of the scaling behavior might lie in both determinacy (erosion) and chance (fluctuations on the surface of the earth).
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  Evolutionary Design Algorithm for Polymorphic Self-checking Circuits Based on Improved Fitness Evaluation

  BAI Lei;ZHU Xiaohua

  . 2012, 30(7): 23-28. https://doi.org/10.3981/j.issn.1000-7857.2012.07.003

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  In order to deal with the problem that in the stage of fitness evaluation while the traditional evolutionary design algorithm is used for polymorphic self-checking circuits, the potential solution is lost, therefore, an improved fitness evaluation method is proposed. As the candidate circuit is evaluated by randomly selecting the output in the traditional algorithm, the fitness evaluation expansion is introduced to adopt full evaluation. The dynamic selection of the output is used to make the most appropriate evaluation for the candidate circuits, avoiding the loss of potential solution. Regarding the result of fitness evaluation expansion for polymorphic circuits, the comparison and selection are proposed to chooce the output with the highest fitness under the both modes, and then the optimal structure is configured. The simulation results of the extrinsic evolution show that the proposed method is able to detect all the stuck-at-faults in the combinational circuits, only using four test vectors. Additional input or output signals are not needed to indicate the faults in the circuits. The carry-out output of the adder is used to show the faults based on oscillations and the original input signals of the circuits could be used as the test signals. Comparing with the traditional evolutionary design algorithm, the evolution generation and the gate number in the circuit are decreased by 90.6%—91.7% and 8%—9.7% respectively. The proposed method gains the advantages of less iterations and lower resources consumption.
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  Influence of Mud Height on the Concentrastion of the Fine Tailing

  YIN Shenghua;WANG Yong

  . 2012, 30(7): 29-33. https://doi.org/10.3981/j.issn.1000-7857.2012.07.004

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  The deep cone thickener is the key equipment for paste manufacture, and the mud height influences the slurry setting velocity and the thickening density in the thickener. The cylinder's static test shows that the settlement velocity of the slurry is the fastest in the disturbance area and without obvious law; the greater the initial height of the slurry, the larger its setting velocity in the setting area; a uniform settlement velocity is found in the compaction area. The concentration of the tailing with different mud heights is studied by the dynamic mixing facility. The results show that, when the mud height is fixed, the rate of the slurry concentration change is gradually reduced as the compaction time is increased. The rate of the slurry concentration change is the highest within 6h. When the compaction time is up to 12h, the rate of the limit concentration change is very small. The limit mass fraction of different mud heights is 71.23%—74.43% at the same compaction time. The analysis shows that when the limit mass fraction of tailings is above 70%, the limit concentration and the height to diameter ratio have a linear relationship. Therefore, the mud height is an important factor which affects the underflow concentration.
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  Genetic Mechanism of Jurassic Heavy Crude Oil in the Northwest Margin of Jugar Basin

  CAI Dongmei;WANG Zhizhang

  . 2012, 30(7): 34-38. https://doi.org/10.3981/j.issn.1000-7857.2012.07.005

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  To reveal the genetic mechanism of Jurassic heavy crude oil in the northwest margin of Jugar Basin, the physical property, group composition and distribution rule of heavy crude oil are analyzed, and researches on hydrocarbon migrating and accumulating in the Jurassic period of this area are associated with, the heavy oil evolution is recovered. The studies manifest that primary oil gas pool in Permian Formation has been superposed and deformed by tectonic movements, thus the hydrocarbon has occurred second migration and accumulated into the overlap Jurassic Formation. In the process of the migration and accumulation, the hydrocarbon has become thicker in according with oxidation and biodegradation, and in the later stage through the virtue of tectonic movement and watered affection, the distribution of heavier crude oil has formed. Heavy oil is favorable for the formation of reservoir and the formation is a quite complicated procedure involving complex geological and geochemical function, therefore, the research on its genetic mechanism plays an important role in the exploration and exploitation.
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  Study of Sedimentary Microfacies of Sayi Reservoir in North Saertu Oil Field

  WEN Huijian;FAN Guangping;MA Shizhong;YANG Cheng;GENG Dongyun

  . 2012, 30(7): 39-43. https://doi.org/10.3981/j.issn.1000-7857.2012.07.006

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  Sayi Reservoir is one of the most important oil layers in the northern Saertu oil field. For a long time, Sayi Reservoir used to be considered to belong to external delta front microfacies with the front sheet sand well developed, but the underwater distributary channel has not been found. With a further exploration and development and well pattern infilling, the distinct underwater distributary channels are found so it is established that Sayi Reservoir belongs to inner delta front microfacies, which include the underwater distributary channel, the front sheet sand, the inner front sheet sand and the external delta front microfacies. Because the underwater distributary channel is an important mark for identifying external and inner delta front microfacies, the typical underwater distributary channel is recognized from the sedimentary facies maps of Sayi Reservoir through analyzing deposition character and establishing logging facies models. The underwater distributary channel sand and the front sheet sand are distinct in sand shape, scale, distribution area, continuous condition and physical property, which decide the development plan and effect. This study can offer not only a new viewpoint for the remaining oil evaluation but also an important geologic evidence for Sayi Reservoir.
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  Several Coloring Problems Involving the Necklace

  LU Jianli;REN Fengxia;MA Meilin

  . 2012, 30(7): 44-47. https://doi.org/10.3981/j.issn.1000-7857.2012.07.007

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  The coloring problem of graph is the classical field of graph theory which is widely used in the network structure and practical life. The coloring problem is becoming a hot topic in recent years. However, the total coloring, especially adjacent vertex-distinguishing total coloring is a difficult point of the coloring problem. For a necklace, the adjacent vertex-distinguishing total coloring, the adjacent vertex-distinguishing vertex edge total coloring, and the incidence adjacent vertex-distinguishing total coloring are discussed when h≥3 (h is able to determine the number of vertices of necklace, h means that the necklace has 2h+2 vertices in the N_h). Through setting up a corresponding relation between the set of vertices and edges and the set of color, the corresponding chromatic numbers of the adjacent vertex-distinguishing total coloring, the adjacent vertex-distinguishing vertex edge total coloring, and the incidence adjacent vertex-distinguishing total coloring are obtained, the chromatic numbers for a necklace are five, three, and four, respectively. At the same time, the corresponding coloring schemes are given.
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  Yield Gaps and High-yielding Design of Corn

  WANG Chongtao;LI Shaokun

  . 2012, 30(7): 48-53. https://doi.org/10.3981/j.issn.1000-7857.2012.07.008

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  There is a huge gap betweem crop's actual and potential yields, among farmers in the same region and in different regions. It is very important to study the formation mechanism of the gap between the actual field yield and the potential yield, and to clear the way and to take technical countermeasures to narrow the gap for increasing the corn production to meet the increasing demand for food in future. Based on a review of studies of crop yield gaps and its causes, and an analysis of the yield formation characteristics of the record yield and the actual field yield related with the yields stability, the structure and the development characteristics of population, the variety selection, the characteristics of cultivation techniques and the climate, soil conditions, a technical program is designed in this paper to achieve a high yield from small plots to large areas. In addition, it is suggested that the realization of the potential yield should be in multi-levels, and the limiting factors to achieve the potential yield, the technical requirements and the yield-increasing ways are also not the same because of the different causes of the gap formation under the different yield goals. Therefore, the objectives, the contents, the structure and the methods of research and promotion of the high-yield technology must be adjusted accordingly in order to achieve the desired objectives.
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  Evaluation on Fire Performance of External Cladding Systems for Buildings

  FU Zhimin

  . 2012, 30(7): 54-62. https://doi.org/10.3981/j.issn.1000-7857.2012.07.009

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  The mechanisms of fire spread by way of the external cladding systems for buildings are discussed. And the standard test methods for fire performance of the external cladding systems for buildings in Europe and America are analyzed. The fire performance classification of external cladding systems and the corresponding fire test requirements are proposed based on the burning characteristics of building materials, construction products and building elements of the external cladding systems and for cases with cavities existing in the external cladding systems. Suggestions are made for developing a fire performance evaluation system for the external cladding systems for buildings in China. The evaluations of the burning characteristics of building materials, construction products and building elements of the external cladding systems are important for keeping the external cladding systems intact without significant fire spread or system collapse. The provisions to limit the susceptibility of the external surface of walls to ignition and to fire spread should be adopted if there are combustible materials and/or cavities in the external cladding systems of buildings. Therefore, the full scale tests for integrated fire performance of the external cladding systems for buildings are necessary, which involve tests for fire resistance, fire spread, and so on. It is urgent to develop the evaluation methods for the integrated fire performance of the external cladding systems and to determine the ensuring mechanism for test specimen to be representative of a facade used in practice, both in constructions and products in China. At the same time, it is necessary to develop a quantitative system of non-combustible, limited-combustible and combustible for building materials, construction products and building elements of the external cladding systems. The fire performance requirements should be established for external cladding systems of buildings in the whole fire safety considerations of buildings. The fundamental and fire test standards should be put forwards clearly in the national general codes for fire techniques. The construction industry should take the responsibility in guaranteeing the fire performance and construction quality of the external cladding systems for buildings.
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  Research Advances in the Pathogenesis of Mycobacterial Cell Wall Lipids PDIM

  HUANG Xinhua;WANG Decheng

  . 2012, 30(7): 63-67. https://doi.org/10.3981/j.issn.1000-7857.2012.07.010

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  Mycobacterium Tuberculosis (MTB) is the pathogen that could induce severe contagious disease. The cell wall of MTB is complexed and composed of complicated components, such as lipids. The envelope of MTB is the high content of lipid, constituting up to 60% of the dry weight of mycobacteria. It has been demonstrated that the prominent role is played by mycobacterial lipids in pathogenesis, notably in tuberculosis. The most lipids are phthiocerol dimycocerosate (PDIM), which is an important cell wall lipid of pathogenic mycobacterium and it has been intensively studied since being shown to promote MTB virulence. Recent studies have suggested that PDIM play a role in cell wall permeability, modulating the early immune responses of murine macrophages, participating in both the receptor-dependent phagocytosis of Mtb and the prevention of phagosomal acidification. However, its cellular and molecular mechanisms of action still remain unknown. Thus, research on the pathogenicity of PDIM not only is helpful to understand the interaction between bacterium and host cell, but also brings a new hope and a breakthrough for the TB treatment.
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  Measuring and Mapping of International Scientometrics and Its Sister Disciplines

  LIU Zeyuan;ZHU Xiaoyu;

  . 2012, 30(7): 68-79. https://doi.org/10.3981/j.issn.1000-7857.2012.07.011

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  At the very inception of the Scientometrics with its sister disciplines-Informetrics, Bibliometrics, and Webometrics/Cybermetrics (referred to as simply SIBW disciplines), they have been made a great progress. Firstly, the history of SIBW disciplines is reviewed as the following three stages, that is, origin and pioneering period (1917—1939), foundation and formation period (1939—1969), and named and booming period (1969—2011). And then the annual distribution of the number of SIBW disciplines literatures during the 1975—2009 is statistically analyzed; the structural and data relationships within the SIBW disciplines are examined from all angles. Furthermore, the recent expansion of SIBW disciplines, their research frontiers, and hotspot area are also discussed by scientometrics and knowledge mapping, the forefront trend of the SIBW disciplines is confirmed through the measurement for two authoritative journals in the field. Finally, the internal relations, common laws, and unified theory of the metrics multi-disciplines are prospected.