28 January 2013, Volume 31 Issue 3

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  • ZHU Yu;CHEN Guangren;SU Qing;
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    Based on the event every year for selecting the annual important advances about science, technology and engineering held by our publishing house, with the same principles of evaluating within each branch, putting quality before quantity, and giving facts in time order, 10 important scientific achievements, 10 important technological achievements and 10 important engineering achievements in China in 2012 were selected from a lot of scientific news in Science and Technology Review, other key academic journals and scientific newspapers. These achievements were introduced by the Editorial Department of Science and Technology Review.
  • Articles
  • CAO Yuan;HAN Feng;WANG Tieliang;LEI Ming;ZHANG Haibo
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    To identify the sensitive factors in mechanical safety of explosion vessels, a parameter sensitivity analysis model based on the Latin Hypercube Sampling (LHS) and the Spearman partial rank correlation analysis methods is built. A great number of numerical simulations and statistical analyses were carried out for the explosion process in a hermetic vessel with this model, the sensitivity values and the orders of related factors were obtained, the impacts of the sample sizes, the parameter distribution types and the parameter value ranges on the sensitivity results were analyzed, and a comparison between the method in this paper and other sensitivity analysis methods was made. It is shown that the volumetric internal energy and the yield strength are the most sensitive factors in mechanical safety of the sample vessel, the tangent modulus is a relatively sensitive factor, while the elastic modulus and the Poisson's ratio are insensitive factors. It is also shown that the volumetric internal energy has a positive correlation with the vessel strain, the Poisson's ratio has no correlation with the vessel strain, while other factors have negative correlations with the vessel strain. The sensitivity analysis method presented in this paper can be used for the sensitivity analysis of various explosion vessels, to provide a quantitative basis for optimizing the vessel safety design and to enhance the safety in tests.
  • ZHAO Guoyan;LIU Dongrui;DONG Longjun
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    The selection and the determination of mechanical parameters are closely related with the stability analysis of laneway and slope in mining engineering. The spot test method to obtain mechanical parameters of rock mass based on the engineering practice is restricted by many environment conditions and technique conditions and is also very costly. Because the blasting disturbance is the most important factor influencing the slope stability for a practical open-pit slope, it should be taken into consideration in the determination of mechanical parameters of slope rock mass. In general, this factor is often ignored in the Hoek-Brown standards for processing the results of indoor rock testing in line with the actual conditions. To address this problem, the nonlinear equation is applied to obtain the relationship between the modified coefficient under disturbance and the integrity coefficient. In this paper, the modified expressions of Hoek-Brown strength criterion, in consideration of the blasting disturbance, are applied to the east slope of the East Gebi open-pit. It is shown that the method in this paper gives good results.
  • LIU Xingguang;GAO Feng;ZHANG Zhizhen;XING Yan;LI Xiru;
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    The damage growth of coal induced by coal mining and gas exploitation conduces to not only the degradation of mechanical properties, but also the modification of interaction between coal and gas. Considering the swelling deformation of coal during adsorbing gas, the effective stress equation for gas-saturated coal under compression is built up based on damage mechanics and porous media theory. The pore pressure effective stress coefficient and adsorption effective stress related with damage evolution of gas-saturated coal are obtained. Then by using the effective stress equation and linear elastic constitutive model, the deformation and effective stress coefficient of gas-saturated coal are computationally analyzed with the different stress conditions. The computing value fits with the test result quite well, the fact indicates the equation is able to effectively describe the mechanical behavior of gas-saturated coal.
  • QIN Yugang;MA Yong;MA Liang;LI Peng
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    Tidal energy is one kind of renewable energy, it is effectively developed and utilized would have the great significance to improve China's energy structure. The tidal current power station is rapidly developing in the areas of technology development and demonstration project, however the studies involving design and performance analysis of the tidal current power station carrier is quite few; it is far from meeting the demand of the fast development of technology applications. Based on the bottom-supported horizontal axis tidal current power conversion technology, the diversion enhanced tidal current power station is focused on, the overall design is proceed, three kinds of carrier scheme are put forward, the fluid dynamic load calculation and strength analysis of the support structure are made. Comparing with the different schemes of the support structure, it could be obtained that both the triangular based and quadrilateral based double support structures are able to meet the strength and deformation demands, wherein the triangular based support structure has better stability and easy to handle, it also has better economy cost. Therefore, the triangular based double support structure is the best option after the analysis. It will provide an important reference for the development and applications of bottom-supported tidal current power station.
  • NI Weining;LI Sanguo;LI Jibo;ZHANG Wei;LI Sheng
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    Caliper measurement by using the traditional wireline multi-finger caliper tools is very difficult under the condition of while drilling. The Logging While Drilling (LWD) caliper tool based on ultrasonic distance measurement possesses the advantages of non-contact, high speed, easy process, and strong anti-jamming. By using three ultrasonic transducers which are equidistantly mounted on the surface, the caliper and the eccentricity are effectively measured. The modular design is utilized for the entire system with the MCU as the core, by drawing lessons from the domestic and international research results of the LWD caliper tool based on ultrasonic distance measurement. In order to design a high precise and eccentricity correcting caliper measurement system, the characteristics of ultrasonic transducer, hardware circuit, and program control are together considered and the collaborative design is used. According to the result of calculation and the parameter characteristics of the real ultrasonic transducers, 1MHz ultrasonic transducers are chosen. Since the variable gain detection circuit and the several gain calibrations are utilized, the first echo signal frontier is captured by the comparator, and the time precision of ultrasonic flight is improved to one period of the ultrasonic transducer oscillation. Finally the measurement precision is effectively improved and the measurement deviation is reached at 1mm.
  • ZHANG Yingzhi;ZHU Dawei;TIAN Wenbo;FENG Cheng;GAO Tianfang
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    With the rapid development of horizontal well technology and the theory of low permeability reservoir exploration, applying the horizontal well to explore low permeability reservoir is an important measure for improving the recovery efficiency of the low permeability reservoir. However, in the previous research, horizontal well is regarded as the production well. Thus the research on the horizontal well as an injection well is rare. Consequently, the water injection technology of the horizontal well provides a new idea for the reasonable exploration of the low permeability reservoir. Considering the current research situation, a 3-D model about the injection capacity evaluation of selective perforation horizontal well is established based on the principle of superposition. The relationship between equivalent radius and perforation length as well as the location of the horizontal well is analyzed; the distribution of the flow and pressure for the horizontal well is discussed based on the established model. All the foregoing theoretical research is applied to the Yushulin Block of Daqing Oilfield and the result indicates that due to its accuracy and reliability, the established model has the important significance of guidance and popularization value for the horizontal well injection exploration of the low permeability reservoir.
  • ZHENG Enming;CHEN Xinhua;SUN Changyu;YU Huabing
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    The Ultra-Short Baseline system(USBL) is a kind of acoustic positioning technology now in wide use. This technique is more convenient than other baselines in view of its small aperture size and the easiness to install. However, the USBL has a low accuracy in a long-range operation because of its small aperture size. This paper proposes a method that improves the positioning precision by optimizing the traditional four-element array. The method requires fewer array elements, or makes it less difficult to build the transmitter as compared with the existing improvements of the USBL array. At the same time, for the application of the new positioning algorithm, this paper proposes a phase compensation formula. The simulation analyses show that the new array can improve the target positioning accuracy by nearly eight times as compared to the traditional ultra-short baseline array in, to achieve the high-precision positioning of distant targets.
  • LI Sheng;LI Junwen;CHENG Tong;GAO Hong;ZHU Xiaoqiang
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    After the coal seam is extracted, the original rock stress is released, under the longwall mining full caving conditions, in the overlying strata above a goaf, a caving zone, a fracture zone (or water suture zone) and a bending belt will be formed, as is normally called the "three zones". In order to calculate two zones' (break and crack zones) height in the overlying strata of the underground coal mining more accurately, with consideration of the fact that the two zones' calculation formula in the specifications covers a too broad range, by using Matlab for the curve fitting, this paper proposes calculation formulas based on the overlying strata strength and the mining thickness, and with a functional relationship between them. The accuracy of the calculation is improved. Through the calculation of the two zones' height of the overlying strata of 22101 working face in Huoluowan coal mine, the calculation method of this paper is verified. It is indeed a more accurate calculation formula for the zones' height for the single long wall fully caving coal.
  • REN Fujun;REN Weihong;ZHANG Yizhong
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    According to previous research findings, starting from the definition of science popularization industry, the common industry research method is applied, tentative survey of its classification and statistical system are conducted. There are two ideas for making the definition of science popularization industry. One is product statistical method; the other is industry statistical method. A comparative study between the two methods is carried out. They both contain pros and cons. However, two methods should be given full play for the advantages of each method and combine them with each other according to present statistics of science popularization industry.
  • Reviews
  • SU Weiguang
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    Propylene oxide is one of important building blocks in chemical industry. Until now, the major conventional manufacturing methods of propylene oxide are the chlorohydrin and the Halcon processes. The chlorohydrin process is phase-out due to environmental pollution, while the latter has the byproduct limitation. The most ideal process is the epoxidation of propylene with molecular oxygen as the oxidant to produce propylene oxide; however the reaction remains one of the biggest challenges in the catalysis field. Propylene epoxidation by oxygen on Cu-based catalysts is just beginning, and until now the relative reports are very few. The green catalytic synthesis of propylene oxide on Ag, TS-1/H2O2, and Au is simply introduced. The advantages and disadvantages as well as industrial application prospect of these systems are discussed, respectively. Then, the recent progress in propylene epoxidation by oxygen over Cu catalysts is detail reviewed. The influence of Cu catalysts preparation methods, alkali metal ions promoters, and metal cocatalysts on the catalytic performances of propylene epoxidation by oxygen is outlined. Finally, the prospects in the field are presented.
  • FAN Guodong;ZHAO Qi;LU Ling;CHEN Hua;LI A'feng
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    Sr2CeO4, with its new unique one dimensional chain structure, can not only be used as a blue fluorescent material, but also serve as a good matrix material. Sr2CeO4 was much studied as one of the development direction of light-emitting materials due to its excellent performance, and as a rare earth doped matrix material, hailed as the second generation of long-lasting light-emitting materials. This paper reviews some evaluation indicators of luminescence properties, the mechanism of luminescence and the influencing factors on the luminescence. Synthetic methods of samples such as the combustion method, the high-temperature solid-phase method, the microwave method, the chemical co-precipitation method, and the sol-gel method are discussed with their advantages and the existing problems. Meanwhile, some ideas about solving the problems are put forward. The characterization of the light-emitting materials and the development of rare-earth-doped Sr2CeO4 in the context of the future research are also addressed.