08 November 2013, Volume 31 Issue 31

    

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  Electro-catalytic Properties of Glassy Carbon Base Pt/C/NH₄NiPO₄ Electrode

  HUANG Yingheng;HOU Lei;TONG Zhangfa;WEI Tengyou

  . 2013, 31(31): 15-19. https://doi.org/10.3981/j.issn.1000-7857.2013.31.001

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  The glassy carbon base Pt/C electrode and the glassy carbon base Pt/C/NH₄NiPO₄ electrode were prepared by the electrodeposition method. The surface morphology of the electrode was characterized by SEM, and the electro-catalytic properties of the electrode were measured by the electrochemical workstation. It is shown that the glassy carbon base Pt/C/NH₄NiPO₄ electrode has better electro-catalytic activity, with a larger oxidation current and a faster electrode reaction rate, and the oxidation process is mainly controlled by the diffusion of the ethanol molecules. The glassy carbon base Pt/C/NH₄NiPO₄ electrode has a potential to replace other electrodes for the ethanol electro-catalytic oxidation, as its first oxidation potential at the positive scanning is reduced by 237mV as compared with the glassy carbon base Pt/C electrode.
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  Homoacetogenic Strain CA3 and Its Optimization Condition for Acetate Yield from Glucose by Fermentation

  LI Jianzheng;YOU Lijian;LIU Chong;BAN Qiaoying

  . 2013, 31(31): 20-24. https://doi.org/10.3981/j.issn.1000-7857.2013.31.002

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  Germplasm resources of homoacetogens are not only the basis for the production of chemical solvent acetic acids but also important for investigating their ecophysiological functions in anaerobic digestion systems. With CO₂ as the carbon source, an anaerobic bacterium strain CA3 was isolated from the anaerobic activated sludge by the modified Hungate anaerobic technique. The strain CA3 is a strictly anaerobic, gram-positive and oval-shaped acetogenic bacterium. This bacterium could metabolize H₂/CO₂ to acetate, and was able to ferment glucose and fructose with acetate as a major product. The phylogenetic analysis based on 16SrRNA gene sequence indicates that the strain CA3 affiliates to the genus Blautia sp.. This strain could grow with temperature in the range from 20℃ to 45℃. With the optimum temperature of 35℃ and the initial pH value of 8.0, an acetate producing rate of 8.92mg/(L·h) was obtained in its pure culture with H₂/CO₂ as the carbon source. The most feasible nitrogen source for the strain CA3 to ferment glucose is the yeast extract and the acetate producing rate reaches 1370mg/L in its pure culture.
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  Effects of Stubble Height on Zygophyllum xanthoxylum (Bunge) Vegetative Growth

  CUI Xiangxin;ZHANG Hanwen;GAO Yong;ZHANG Liwen;YANG Yonghua;CHAO Gejile;DONG Xue;DONG Jie

  . 2013, 31(31): 25-30. https://doi.org/10.3981/j.issn.1000-7857.2013.31.003

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  In oder to protect the natural desert plant Zygophyllum xanthoxylum (Bunge) in the western Ordos national nature reserve according to a plan, and to maintain its ecological niche, by taking Z. xanthoxylum growth recession as the research object, six different stubble heights (-3(under ground), 0(on ground), 3(over ground), 5(over ground), 10(over ground), 15cm(over ground)) were selected, to investigate the effects on its vegetative growth. It is shown that, ① For different stubble heights, the overall effect with respect to the number of branches, the length and the diameter of Z. xanthoxylum of the different brush is better than that of the same brush;② For different stubble heights, its height grows higher than the control, the highest is that with the stubble height of 3cm, 3.64 times as the control;the number of new branches is larger than that of the contrast, with a difference of up to 23.08 times at the stubble height of 3cm for the different brush, and 5.45 times for the same brush;The diameter of new branches is larger than that of the contrast, with a difference of up to 1.58 times at the stubble height of 3cm for the different brush, and 1.25 times for the same brush;The length of new branches is larger than that of the contrast, with a difference of up to 2.63 times at the stubble height of 3cm for the different brush, and 1.98 times for the same brush;③ The membership function analysis shows that for the different brushes, the vegetative growth of Z. xanthoxylum is in the following order according to the stubble height: 3cm>0cm>-3cm>10cm>15cm>5cm;For the same brush, the order is 10cm>-3cm>5cm>0cm>15cm>3cm.
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  Did the Occurrence of M_s7.0 Lushan Earthquake Relate to Reservoir?

  CHENG Huihong;ZHANG Huai;SHI Yaolin

  . 2013, 31(31): 31-37. https://doi.org/10.3981/j.issn.1000-7857.2013.31.004

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  After the occurrence of the M_s7.0 Lushan earthquake on April 20, 2013, many media pointed that the occurrence of the Lushan earthquake was related with Three Gorges reservoir or Zipingpu reservoir or Pubugou reservoir, and so on. However, the qualitative arguments cannot give a reasonable conclusion. So, according to the previous studies, the analytic method is adopted to quantitatively analyse the impact of the Three Gorges reservoir, Pubugou reservoir and Zipingpu reservoir on the hypocenter of the M_s7.0 Lushan earthquake. The changes of elastic stresses and pore pressure of each reservoir to the M_s7.0 earthquake are calculated, respectively. The initial results indicated that the elastic stress changes induced by the Three Gorges or Pubugou or Zipingpu reservoirs are only dozens of Pa. When the diffusion coefficient is less than 1m²/s, the pore pressure changes of the hypocenter of the M_s7.0 Lushan earthquake are equal to zero, which means that the impoundment of the three reservoirs had no effect on the M_s7.0 Lushan earthquake. When there is a fault with a high permeability (diffusion coefficient is larger than 10m²/s) and extension of more than 100 km, the pore pressure changes of the hypocenter of the M_s7.0 earthquake could reach 3.2kPa and the coulomb stress change is 1.9 kPa. However, such a fault seems exceedingly unlikely. When a larger appropriate diffusion coefficient (1m²/s) is selected and 100 years filling of all the three reservoirs are supposed, the pore pressure and coulomb stress changes reached only several kPa. So, it can be confirmed that the impoundment of Three Gorges reservoir or Zipingpu reservoir or Pubugou reservoir is irrelevant to the occurrence of the M_s7.0 Lushan earthquake.
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  Mining Method Optimization Based on GRA and Weighted TOPSIS Method

  ZHANG Qinli;CHENG Jian;WANG Xinmin;ZENG Jialong;SONG Guangchen

  . 2013, 31(31): 38-42. https://doi.org/10.3981/j.issn.1000-7857.2013.31.005

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  In order to choose an appropriate mining method, a synthetic assessment index system was established. A comprehensive evaluation index system model based on the basic theory of the Analytic Hierarchy Process (AHP), the Grey Relation Analysis (GRA) and the weighted TOPSIS was established to optimize the mining methods. During the process, the evaluation indexes in the mining method were comprehensively considered in view of economy, technology and security. The weight matrix of the evaluation indexes was established according to the AHP method, then, according to the weighted TOPSIS improved by the grey relational coefficient, a weighted TOPSIS-GRA comprehensive evaluation model was established, and the synthetic superior degree of the mining methods based on the influence factors was obtained by the TOPSIS methods. Taking the mining method optimization in the transition from the open pit to the underground mining in Shirengou Iron Mine as an example, the synthetic superior degrees of four kinds of optional mining methods are 47.9%,62.5%,63.9% and 59.9%, respectively. According to this analysis, the third mining method is the best. The feasibility and the effectiveness of the evaluation model are verified by the mine's production practice.
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  Construction and Quantitative Analysis of Evaluation Index System on Stability of Filling System

  LI Xibing;WEI Wei;ZHAO Bin

  . 2013, 31(31): 43-47. https://doi.org/10.3981/j.issn.1000-7857.2013.31.006

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  Filling method is widely used in the deep process of development of mineral resources. As an important component of filling mining method, filling system stability with fuzzy and stochastic influencing factors, is a complex system which consists of many sub-systems. In this study AHP is introduced, and influencing factors are quantitatively analyzed from five aspects of raw materials, slurry preparation system, slurry delivery system, mining areas and other factors. The results show that pipeline anti-wear technology, the anti-burst pipe way, filling slurry mix ratio, decompression means, filling slurry concentration, slurry filling slump, gelling agent have the greatest impacts on the stability of filling system. The results provide a scientific and reasonable theoretical basis for the design of filling system used in the mine production.
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  Analysis on High Water Cut Ratio Well in Horizontal Well Pattern with Numerical Simulation Method

  XIONG Bo;LEI Qun;

  . 2013, 31(31): 48-52. https://doi.org/10.3981/j.issn.1000-7857.2013.31.007

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  Horizontal well is an important method for the effective development of the low permeability reservoir. The research of the water producing has important guiding significance to the successful application of this technology. Based on the analysis on the defects of handling the fractures by conventional numerical simulation method, a new method is established to handle fractures for the numerical simulation of horizontal well. The influence of angles between the wellbore and the fracture, fracture parameters including fracture number, single-wing length and conductivity on the production and water ratio was researched. The results of numerical simulation indicate that fracture number has the most significant influence on recovery which is followed by single-wing length and conductivity with respect to the fracture parameters. The present method was applied to the test area of horizontal well. The production performance of the horizontal well groups was simulated by means of the established method. It is shownd that the main cause for the high water cut is the connecting of the partial hydraulic fractures between the horizontal well and the injection well. Thus the new readjustment plan which recommends shut in partial horizontal wells or producing new fractures after plugging the existing hydraulic fractures was presented. The plan was applied to the production field and favorable response was achieved.
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  Design Calculation Methods of Coaxial Pipe Type Ground Heat Exchanger

  GONG Guangcai;CHEN Fan;SU Huan;YI Zhiping

  . 2013, 31(31): 53-56. https://doi.org/10.3981/j.issn.1000-7857.2013.31.008

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  In this paper, a simplified model of the coaxial pipe type ground heat exchanger is built based on the theory of the line heat source and a design method of the coaxial pipe type heat exchanger based on the thermal response test is proposed. The method is used to obtain the complex thermal conductivity coefficient and the total thermal resistance of a borehole of a practical project in Shaoshan of Hunan Province, and the results are compared with test values. Meanwhile, the complex thermal conductivity coefficient and the total thermal resistance of another borehole of a double-U pipe in the same project is also tested and calculated for a comparison. The calculation method is proved to be applicable for the coaxial pipe type ground heat exchanger by analyzing the intrinsic relationship of the two tests with respect to the complex thermal conductivity coefficient, the total thermal resistance, the temperature difference of the heat transfer and the heat transfer rate. With this method, the complicated calculation of the thermal resistance of the inner layer of the borehole can be avoided and therefore, the calculating process is simplified. This method can be used for practical projects.
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  Experimental Study of the New Anti-dance Fittings for 500kV Transmission Line

  GAN Fenglin;XIONG Xiangzhi;HU Haipeng;WANG Qi

  . 2013, 31(31): 57-60. https://doi.org/10.3981/j.issn.1000-7857.2013.31.009

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  A new kind of anti-dance fittings is composed of vibration-reducing and anti-dance damping spring interphase spacers to absorb the vibration energy of the wire through a spring, rubber and heavy ball system. The wire fatigue vibration test system platform is used to conduct the galloping tests of two phase six bundled wires installed with the ordinary interphase spacer and the vibration-reducing and anti-dance damping spring interphase spacer. The wire's vertical and horizontal displacements are measured against time after the movement becomes stable. It is concluded that the displacement of the wire is smaller when it is installed with the vibration-reducing and anti-dance damping spring interphase spacer under the same conditions and that the vibration-reducing and anti-dance damping spring interphase spacer has a better anti-dance performance and is a very practical anti-dance hardware, which can be applied in the transmission line.
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  Analysis of Aircraft Noise-distance Characteristic Curve Based on Robust Least-squares Estimation

  CAI Liangcai;ZHU Jiale;WANG Haifu;LIU Zhou

  . 2013, 31(31): 61-65. https://doi.org/10.3981/j.issn.1000-7857.2013.31.010

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  The noise-distance characteristic curve is an important technical index, which can only be obtained by fitting the data of the field test. In view of the fact that there are errors in the test of L_EPN and the least distance from test points to flight tracks, the robust theory is applied to balance the discreteness among data. The robust least-squares method and the IGGI weighting-function method are chosen to determine the coefficients in the formula according to the form of the aircraft noise-distance characteristic curve, and the aircraft noise-distance characteristic curves for takeoff and landing are obtained based on the formula. An example of takeoff and landing for a type of aircraft is taken to test and verify the feasibility of the method proposed in this paper. This paper provides a theoretical basis for the environmental impact assessment of the airplane noise in airport.
Reviews
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  Aircraft Wake Detection Technology Research and Application Prospects

  DAI Huanyao;DI Dongning;QIAO Huidong;CUI Jianling

  . 2013, 31(31): 66-69. https://doi.org/10.3981/j.issn.1000-7857.2013.31.011

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  The aircraft wake is a special fluid mechanics feature in an air powered aircraft flight, which is strong, stable, with a long duration and with large spatial scales, so it can be effectively detected by radar, laser radar, sonar sensors. The turbulent flow nature of the aircraft wake leads to a unique electromagnetic scattering property, so the radar detection technology of the aircraft wake is of great value in military and civil applications. This paper reviews the state of the art of the international research of the aircraft wake detection technology from three aspects: The aircraft wake electromagnetism computation, the aircraft wake measurement experiment and the aircraft wake detection theory. It is pointed out that the technology had prospective applications in the civil aviation, the anti-stealth detection, the radar anti-jamming, the aircraft carrier takeoff and landing, and the target tracking. The development of the wake detection radar and the principle testing experiment will further promote the development of the airport, and radar anti-stealth technology in China.
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  Key Factors of Shale Gas Development

  FANG Dazhi

  . 2013, 31(31): 70-74. https://doi.org/10.3981/j.issn.1000-7857.2013.31.012

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  Shale gas is a kind of unconventional gas. Shale gas reservoirs are typically continuous, having complex texture with low porosity and low permeability, so they needs advanced technology for production. Current situation of shale gas development in China and abroad is summarized. Through in-depth investigating and summing up shale gas exploration and production history and successful experience in North America, it is thought that key factors of shale gas effective production includes optimization of sweet areas and drilling and fracturing techniques. Comprehensive geological evaluation is the basis for shale gas development, and reservoir reconstruction technique is the core of producing reserves. The main geological parameters for selection shale gas enrichment areas and main aspects for drilling and well completion optimization are introduced. Together with actual comparison of the geological and engineering parameters in different shale gas wells, the ideas of successful shale gas development are proposed. Based on the study of reservoir description and evaluation, specific fracturing design and reasonable engineering parameters should be carried out in order to increase the ESRV(Effective Stimulated Reservoir Volume) and obtain high production.
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  Progress in Photocarrier Separation and Transport on Fe₂O₃ Semiconductors

  SU Weiguang;MA Baojun

  . 2013, 31(31): 75-79. https://doi.org/10.3981/j.issn.1000-7857.2013.31.013

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  There is an increasing interest in the use of solar energy to drive the photolysis of water into molecular hydrogen by inorganic nanoparticles and photoelectrodes, which is the most ideal process to solve the energy crisis. However this reaction remains one of the biggest challenges in the photocatalysis field. Fe₂O₃ is one of the most promising materials for its application in energy and environmental fields due to its narrow band gap to absorb a large part of visible spectrum in sunlight as well as the abundant resource, the low price and environment friendliness. However, until now the reported solar-to-chemical energy conversion efficiencies of Fe₂O₃ are too low because of its ultrafast e/h recombination rate, which restrict the development of Fe₂O₃ photocatalysts. The recent progress in photocarrier separation and transport on Fe₂O₃ nano-semiconductors is reviewed in this paper. The influencing factors on the incident photo-to-current efficiency of Fe₂O₃ photocatalysts are discussed, including the heteroatom doping, the Fe₂O₃ sensitized by other semiconductors with different energy levels to form heterojunction, as well as the Fe₂O₃ with different nanostructures and nanosizes. The separation and the transport of the photo-generated electron hole pair play a pivotal role in the photoelectrocatalysis hydrogen production from water splitting on Fe₂O₃ semiconductors. A longer life of the photocarrier means a higher photocatalytic performance of Fe₂O₃. Finally, the principle, the design idea, the effects and the shortcomings of Fe₂O₃ are discussed, and the development direction of the Fe₂O₃ photocatalysts in the future is also addressed.