28 March 2011, Volume 29 Issue 11-09
    

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    Articles
  • Application Mode of Severe Accidents Criteria to the Partition of Nuclear Power Plant Emergency Planning Zone
    . 2011, 29(11-09): 22-25. https://doi.org/10.3981/j.issn.1000-7857.2011.09.002
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    As the technical criteria，it is required that the severe accident sequences should be considered in the partition of nuclear power plants Emergency Planning Zone (EPZ). In the relevant national standards and nuclear safety guide rules, the dose criteria involving 'majority severe accident sequences' and 'the severest accident sequences' are proposed. However, in the actual applications of these criteria, there might be some different understanding to the concept of 'majority severe accident sequences' and 'the severest accident sequences'. The source terms of PWR1—PWR7 release categories in WASH1400 are selected as the referenced source terms, and the individual consequence of each source term and the weighted average of these consequences are calculated and analyzed by using MACCS code. Then the impacts of the results of two different calculation approaches on EPZ size are compared with each other. The conclusion shows that the weighted average of the severe accident spectrum consequences can basically reflect the assessment results of each severe accident consequence and the consideration for emergency planning cost to a certain extension. This means that using the weighted average of the severe accident spectrum consequences as the technical criteria for the partition of EPZ can better embody the trade-off principle between the risk mitigation and cost.
  • Breeding of Manganese-oxidizing Bacteria and Application of Manganese Removal by Immobilization Technology
    . 2011, 29(11-09): 26-30. https://doi.org/10.3981/j.issn.1000-7857.2011.09.003
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    Manganese is one of most important elements for the people health, but drinking water with excess manganese will cause chronic poisoning for the people. Thus there is a need for developing effective manganese removal method in the water treatment. Due to the high efficiency and low cost, biological manganese removal technology has been investigated and applied to many cases. The manganese removal is achieved in here by oxidizing Mn2+ bacteria. Three high manganese oxidizing bacteria which were gram-positive were screened from the mature filtration column and their physiological and biochemical characteristics were investigated. All three bacteria can grow well in wide range of pH and temperature. The removal efficiency of Mn2+ by these bacteria could reach at more than 86% in both eutrophic and oligotrophic conditions. The removal efficiency of Mn2+ is increased with time in the logarithmic stage. The cells are embedded with the mixed PVA and Alginate. The results show the high mechanical strength and good mass transfer performance. The maximum removal rates of Mn2+ by the three bacteria are all above 85.6% when the columns are filled with the mixed immobilized balls and the low-cost river sand.
  • Structural Feature of South Beir Sag
    . 2011, 29(11-09): 31-35. https://doi.org/10.3981/j.issn.1000-7857.2011.09.004
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    Because Hailar-Tamtsag Basin is a Mesozoic-Cenozoic rift basin, and developed on the basis of Tianshan-Xing'an Variscan orogenic system. And Hailar-Tamtsag Basin was strongly influenced by the late tectonism, the architecture of the basin and its evolution is very complicated, the advances in fundamental geological researches are slow, and seriously impede the progress of oil and gas exploration. Based on the 3D seismic data of Nanbeier Sag, a structural analysis for the working block is conducted, the architecture characteristic of the sag is found out, the regularity of the tectonic evolution is summarized, and the tectonic formation mechanism is analyzed on the basis of the system interpretation of 3D seismic data. And the structural styles of Nanbeier depression can be divided into five groups, that is, weakly rifting stage, intensely rifting stage, reversely compressing stage, transtensional depression stage, and transpressional depression stage. It has an important significance for the geologic understanding of Nanbeier sag and even the whole Hailar-Tamtsag Basin, and accelerates the oil and gas exploration process of Nanbeier sag.
  • Environmental Effects of the Wenchuan Earthquake in Mountain Areas
    . 2011, 29(11-09): 36-41. https://doi.org/10.3981/j.issn.1000-7857.2011.09.005
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    Based on previous studies of Wenchuan earthquake, combined with the results of field studies in August 2010, with human factors as the focus, the mountain environment system can be divided into three sub-environmental systems, that is, the natural environment, the social environment and the ecological environment of the mountainous area. Accordingly, this earthquake would be related with four environmental effects in three sub-environmental systems including destructive effects for the natural environment, earthquake damage effects and inductive effects for the social environment and ecological effects for the ecological environment. These environmental effects of Wenchuan strong earthquake in mountain regions were systematically analyzed. These hazard effects are dramatic and are closely related to one another. Some of them were almost simultaneous or one following another, with a tremendous destructive effect in the earthquake-hit areas. The analysis of environmental effects of the Wenchuan earthquake in mountain areas can provide a scientific and theoretical basis for environmental recovery.
  • Modeling Analysis on the Gyro Stabilized
    . 2011, 29(11-09): 42-47. https://doi.org/10.3981/j.issn.1000-7857.2011.09.006
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    Modeling analysis is a key step to study and design the gyro stabilized platform. A reasonable platform model is a big help for analyzing the error sources and designing appropriate control strategies. It provides the foundation for researching high-precision gyro stabilized platform. Based on the description of the platform's hardware and single-axis control structure, the error sources and coupling between axes are analyzed. Then, modeling and analysis methods are studied for non-linear friction, gyro drift, and mechanical resonance, the three main factors have influence on the precision, and the models for other parts of the platform are also discussed. Based on the above modeling analysis, an overall model which is comprehensive for decoupled single-axis control system is given. This model is consisting of four loops, namely, current loop, velocity loop, stability loop, and position loop. In this system, the LuGre friction model is chosen to characterize the non-linear friction. In addition, the characteristics of the control system are also illustrated. A reference for modeling analysis and designing error compensation strategy of gyro stabilized platform based on the modular modeling is provided.
  • Numerical Simulation of Vortex Air Curtain Suction Dust Control System and Its Applications
    . 2011, 29(11-09): 48-52. https://doi.org/10.3981/j.issn.1000-7857.2011.09.007
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    The system of suction dust control via vortex air curtain can effectively control the spread of gas load dust. In order to solve the problem of large dust concentration in a fully mechanized excavation face, the forming mechanism for the dust resistance of vortex air curtain is studied based on the phase flow theory and the characteristics of gas-dust particle two-phase flow. The mathematical model of k-ε-Θ-kp is established and used to solve the diffusion law of suction dust control via vortex air curtain. And based on the Simple algorithm with a grid, the pretreatment software Fluent is adapted to conduct the numerical simulation on the spatial distribution law of dust concentration in a fully mechanized excavation face. The simulation result shows that a lot of dust could effectively enclose in a range of 0.5m from tunneling place to the front of road header driver via vortex air curtain suction dust control. According to the simulation results and the actual conditions of working face on-site, the system of suction dust control via vortex air curtain in a fully mechanized excavation face is designed. The system is composed of pane wall of fan drum and dust-removing and cleaning device. After applying vortex air curtain suction dust control system to a fully mechanized excavation face, the average sedimentation rate of the whole dust and respirable dust are as high as 94.4% and 93.7%, respectively, which effectively reduces the dust concentrations on work-site locations face in a fully mechanized excavation face, and achieves a good dust fall effect. The promising development prospect of vortex air curtain suction dust control system for solving the problem of the large dust concentration in a fully mechanized excavation face are adequately explained through the discussion.
  • Parameter Identification of the Tire Model Based on an Improved Partical Swarm Optimization Algorithm
    . 2011, 29(11-09): 53-56. https://doi.org/10.3981/j.issn.1000-7857.2011.09.008
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    Tire is an important part of the vehicle. The behaviour of the tire is of basic importance to the vehicle dynamics, and plays a vital role in vehicle's performance, so the precision of a tire model affects the simulation reliability of the whole vehicle model. Partical swarm optimization algorithm is used to identify the tire model parameters in this paper. According to the organic evolution in nature, the multi-population with a variation threshold partical swarm optimization algorithm is proposed to keep the population diversity and improve the reliability of holistic convergence. The variation threshold is to avoid the problem of converging to a part-optimum. Comparing the simulation results with the test results, it is shown that the simulation data from the multi-population with a variation threshold partical swarm optimization algorithm would fit the test data better than those from other optimization algorithms, the identification accuracy is slightly higher. The multi-population with variation threshold optimization algorithm has a good application prospect in tire parameter identification.
  • Crank-Nicolson Block-centered Finite Differences Method for Hyperbolic Problems
    . 2011, 29(11-09): 57-61. https://doi.org/10.3981/j.issn.1000-7857.2011.09.009
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    The Crank-Nicolson block-centered finite difference method studies the solution of the linear hyperbolic differential problems in the bounded domain with sufficiently smooth data. This method is based on both block-center finite difference method and parabolic Crank-Nicolson format. Both the approximate solution and its first derivatives are obtained for all non-uniform grids. Its characteristics are that the approximate solution according to the discrete L2-norm is achieved optimal order error estimation, and the approximate solution of the first derivatives is reached at super convergence error estimation. This method does not increase the calculation. Numerical tests are identical with theoretical analysis; it explains that the format possesses the efficient convergence.
  • The Expression and Clinical Significance of C-erbB-2, MMP-1, MMP-2, MMP-7 and MTA1 in Esophageal Cancer of the Kazak
    . 2011, 29(11-09): 62-65. https://doi.org/10.3981/j.issn.1000-7857.2011.09.010
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    The expressions of C-erbB-2, MMP-1, MMP-2, MMP-7 and MTA1 in esophageal cancer tissue and normal tissue among the Kazak are studied and the relationship between their expressions and clinical pathological feature is investigated. The expression of C-erbB-2, MMP-1, MMP-2, MMP-7 and MTA1 gene mRNA were detected by using RT-PCR method in 75 esophageal cancer specimens of the Kazak. The results show that the positive rates of C-erbB-2, MMP-1, MMP-2, MMP-7 and MTA1 in cancer tissue are higher than that of normal tissues (P＜0.05)． While the expression mRNA level of MMP-2, MMP-7 and MTA1 is significantly related to the lymphnode metastasis，And the expression mRNA level of MMP-1, MMP-7 is significantly related to the TNM stages (P＜0.05)． Kappa analysis indicates that the expressions between C-erbB-2 and MTA1, MMP-2 and MTA1, MMP-7 and MTA1, MMP-7 and MMP-1, MMP-1 and MTA1 in the Kazak's esophageal cancer are positively related (κ=0.624, 0.367, 0.564, 0.275, 0.384, P＜0.01) with each other. The conclusion shows that the over expression of C-erbB-2, MMP-1, MMP-2, MMP-7 and MTA1 gene could play the important roles in the carcinogenesis of esophageal cancer in the Kazaks. Their synergistic effect could promote carcinogenesis and development of esophageal cancer. The expressions of MMP-2, MMP-7, and MTA1 might be related to the progression and metastasis of esophageal cancer among the Kazak．
  • On the UVB Screening Effect of Four Species Forest in Inner
    . 2011, 29(11-09): 66-69. https://doi.org/10.3981/j.issn.1000-7857.2011.09.011
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    The four familiar species of conifer forest in Inner Mongolia i.e. Larix gmelini, Pinus tabulaeformis, Pinus sylvestris, and Picea meyeri were chosen as the investigative objects in forest area of Daxinganling Mountain and Hohhot City. The UVB radiation values were measured under the shade conditions and in the sunshine by using PC-2 solar radiation sensors. The UVB Shielding efficiency of examined tree species was calculated. The difference of UVB screening efficiency was compared with. And using the Pearson correlation analysis method, the UVB screening effect of different forest and its related characteristics, such as average canopy diameter, coverage, average height, and average bifurcate height, were concluded. The results show that: (1) Distinct weakening effect is achieved in the four familiar species of conifer forest. The UVB shielding efficiency for Larix gmelini is 91.2%, for Pinus tabulaeformis is 88.9%, for Pinus sylvestris var. mongolica is 88.2%, and for Picea meyeri is 90.2%, respectively. However with the different forest and time, their effects on the UVB shielding efficiency are insignificant. (2) There is a significantly positive correlation between the UVB shielding efficiency and coverage. There is a significantly negative correlation between the UVB shielding efficiency and average canopy diameter. There is an insignificant correlation between the UVB shielding efficiency and the average height of plant, and the average bifurcate height of plant.
    • Reviews
  • Analytical Methods for the Determination of Estrogens and Progestogens in Wastewater
    . 2011, 29(11-09): 70-75. https://doi.org/10.3981/j.issn.1000-7857.2011.09.012
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    Estrogens and related synthetic compounds have been detected in the aquatic environment, mainly as a result of effluent outfalls of inefficient removal in Waste-Water-Treatment Plants (WWTP) and the excrement of aquaculture and poultry. These compounds show the high physiological activity with very low concentrations and have been associated with certain alarming effects on reproduction and developmental processes. Even with a concentration of 5—6ng/L, 17α-ethynylestradiol can exterminate entire fish populations in a whole lake experiment within three years due to the feminization of male fishes. In the last 10 years, an increasing number of studies have been conducted to develop analytical procedures for estimating the levels of the estrogens in the influent and effluent of WWTP and evaluating the risk to human beings and ecosystem. Due to the low concentration and complicated matrix in the wastewater, the determination of natural and synthetic estrogens in wastewater becomes a difficult analytical task. The existing analytical methods for the analyzing these estrogens in wastewater from samplings to procedures, and the methods commonly used in the determination are reviewed.
  • Effects of Various Dopant on Photoluminescence of GaN Based Materials
    . 2011, 29(11-09): 76-79. https://doi.org/10.3981/j.issn.1000-7857.2011.09.013
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    Gallium Nitride (GaN)-based materials have great advantages, such as direct and large band-gap, high critical field strength and thermal conductivity, high carrier saturation velocity, and high mobility and concentration of two-dimensional electron gas at hetero-junction interface, the advantages determine that the GaN-based materials and devices play an important role in the area of light-emitting semiconductor materials. Thus, the preparation of high quality GaN-based materials doped with various elements has become one of interesting research topics. The recent advanced researches and developments are reviewed and it mainly focuses on doped GaN-based materials, including GaN doped with group IIA elements, the transition elements, and the rare-earth elements; and also the effects of different dopant on the growth and optical properties of GaN-based materials are analyzed. Moreover, the advantages and disadvantages of various doping technologies have been further compared by taking Mg-doped GaN as a typical example

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