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   Science & Technology Review
2013, Vol.31, No. 19
08 July 2013

Articles
Reviews
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卷首语

Science & Technology Review. 2013, 31 (19): 3-3. ;  doi:
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Abstract ( 107 )
科技风云

Science & Technology Review. 2013, 31 (19): 7-7. ;  doi:
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Abstract ( 134 )
特别栏目

Science & Technology Review. 2013, 31 (19): 8-8. ;  doi:
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Science & Technology Review. 2013, 31 (19): 8-8. ;  doi:
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Science & Technology Review. 2013, 31 (19): 10-10. ;  doi:
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Science & Technology Review. 2013, 31 (19): 11-11. ;  doi:
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Science & Technology Review. 2013, 31 (19): 12-12. ;  doi:
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Science & Technology Review. 2013, 31 (19): 13-13. ;  doi:
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Science & Technology Review. 2013, 31 (19): 14-14. ;  doi:
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Science & Technology Review. 2013, 31 (19): 81-81. ;  doi:
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Science & Technology Review. 2013, 31 (19): 82-82. ;  doi:
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Science & Technology Review. 2013, 31 (19): 86-88. ;  doi:
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Science & Technology Review. 2013, 31 (19): 89-89. ;  doi:
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Science & Technology Review. 2013, 31 (19): 90-92. ;  doi:
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Science & Technology Review. 2013, 31 (19): 94-94. ;  doi:
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Science & Technology Review. 2013, 31 (19): 95-95. ;  doi:
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Science & Technology Review. 2013, 31 (19): 96-96. ;  doi:
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科技事件

Science & Technology Review. 2013, 31 (19): 9-9. ;  doi:
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Abstract ( 111 )
Articles

Blast-hole Reasonable Stemming Length for Raise Excavation Using One-step Deep-hole Blasting

LI Qiyue;LIU Bingchuan;CHEN Liang;LI Jinyue
Science & Technology Review. 2013, 31 (19): 15-19. ;  doi: 10.3981/j.issn.1000-7857.2013.19.001
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Abstract ( 345 )
Stemming length is one of the most important parameters during the raise excavation by one-step deep-hole blasting. For properly determining the blast-hole stemming length and improving the blasting effect of one-step deep-hole blasting, a study is carried out. Rock fragmentations are checked up to analyze how stemming length has an effect on raise excavation by one-step deep-hole blasting. Based on the material characteristics of hole stemming and the theory of elastic-plastic mechanics, the deformation calculation model of stemming under the explosion load has been set up. Based on the energy transfer in the process of deformation and movement, and the relation among the time when the stemming moves out of the hole, the time that rock crushes, the time that blasting crater forms, and the time that adjacent stratified rock starts to break, the stemming theory of one-step deep-hole blasting has been deduced from the theorem of kinetic energy. In the experiment with a 32 meters filling up raise located at Sandaozhuang mining area, the stemming theory is applied to; combining with the actual engineering geological conditions, the actual stemming length is selected, an explosive solution is formed, and the raise excavation by one-step deep-hole blasting wins a success. And the stemming theory has been verified and it provides the guidance for raise excavation by one-step deep-hole blasting.

Influential factors of Horizontal Well Volume Fracturing Productivity in He 8 Tight Gas Reservoir

SU Yuliang;YUAN Bin;LI Shuoxuan;GU Yonghong;LI Hongying;SU Guohui
Science & Technology Review. 2013, 31 (19): 20-25. ;  doi: 10.3981/j.issn.1000-7857.2013.19.002
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Abstract ( 393 )
Volume fracturing technology could result in a seam-cross network, which is conductive to the development of tight gas reservoir. The horizontal well volume fracturing model is established by considering stress sensitiveness and wellbore friction based on He 8 tight gas reservoirs characteristics. The effect of geologic factors and network features on the efficiency of horizontal well volume fracturing is analyzed by the numerical simulation of different geological conditions. The result shows that network fracturing could change the seepage environment, increase reservoir production extent, improve well performance greatly; the processing factors have different influential extents. The pressure coefficient and permeability mainly affect the volume fracturing efficiency, with the increase of effective remolded volume, the productivity improvement could be more distinct, network width and length, fracture conductivity, and network distribution successively affect volume fracturing remolded efficiency. The research result provides the theoretical basis for both optimal design and effectiveness evaluation of volume fracturing in the tight gas reservoir.

Stress Sensitivity Experiment under Consideration of Stress Arching Effect

WANG Fanliao;LI Xiangfang;HAN Bin;ZHANG Xin;LI Yingying;ZHAO Jingjing;
Science & Technology Review. 2013, 31 (19): 26-32. ;  doi: 10.3981/j.issn.1000-7857.2013.19.003
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Abstract ( 191 )
Low Permeability reservoir is quite sensible to the effective stress. Current all sensitive experiments suppose that the overburden pressure is a constant during the production. Actually, during oil and gas exploitation, a stress arching effect comes into play in the overburden, reducing the overburden pressure acting on the reservoir. Based on the theory of the stress arching, the stress-to-arching ratio, overburden pressure, and effective stress expression in Su Lige gas field are calculated. It is the first time that the theory is applied to the stress sensitive experiments. The experiments take the reservoir shape and different range of initial permeability into consideration. The results show that the stress-to-arching ratios are 0.12 and 0.28, respectively for the elliptic cylinder reservoir and penny-shaped reservoir in Su Lige gas field. Comparing with the conventional experiments, under the same condition, the measured permeability is usually higher and the degree of the sensitivity is smaller. When the pressure drops 25MPa, for the stress-arching-ratios of 0.12 and 0.28, the measured permeability are 1.2 and 1.5 times of the permeability value obtained by conventional experiments for the reservoir with low permeability, which initial permeability is smaller than 0.1mD. However, when the initial permeability is between 10mD and 50mD and stress-to-arch ratios are 0.12 and 0.28, respectively, the corresponding permeability are 1.01 and 1.02 times of the permeability got by the conventional experiments. The low permeability gas reservoir is more sensitive to the stress arching than the high permeability gas reservoir.

Rule of Adjustment for Reflecting Prisms

LIAN Tongshu
Science & Technology Review. 2013, 31 (19): 33-38. ;  doi: 10.3981/j.issn.1000-7857.2013.19.004
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Abstract ( 206 )
This paper is devoted to introducing refinement into the theory of adjustment for reflecting prisms based on the fact that the characteristic matrix ST,2φ of a reflecting prism could also be regarded as a transmission matrix in case the input to the prism is an angular vector. Thanks to this new conception, the two rules, related respectively to a small angular displacement ΔθP and a small linear displacement ΔgD of a reflecting prism have significantly been rewritten in terms of the definition of the rules and even the title of themselves. Thus, the theory of adjustment for reflecting prisms will come up to quite a high level in scientific and logical sense.

Best Selective Scheme for the Filling Station Location of a Certain Mine

ZHANG Qinli;XIAO Chongchun;CHEN Qiusong;WANG Xinmin;XU Dan
Science & Technology Review. 2013, 31 (19): 39-43. ;  doi: 10.3981/j.issn.1000-7857.2013.19.005
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Abstract ( 213 )
Filling station location is a throat engineering of the filling mine. Furthermore, whether or not the location of filling station is reasonable is the key to a new built filling system. In order to solve the problem about the optimal selection of filling station scheme, an evaluation indicator system of filling station scheme is established. The economy, technology, environment, and safety factors are comprehensively considered in order to establish the evaluation indicator system. In the establishment process of comprehensive evaluation index, the methods of on-site research, data analysis, and consultation with experts are used to ensure the reliability of the evaluation indicator system. Then, the basic theories of Analytic Hierarchy Process (AHP), Entropy Method (EM), and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) are adopted to evaluate the filling station scheme for determining the optimal filling station location. During the evaluation process, the AHP is used to decide the subjective weights of evaluation indexes, combining with the objective weights that calculated by EM, the balanced weights are gotten. By that way, the impacts of subjective and objective factors on the weights of evaluation indexes are evened up. Then, the AHP&EM-TOPSIS comprehensive evaluation model is established with the basic theory of TOPSIS. Finally, by calculating the superior degrees of each filling station site scheme based on the comprehensive evaluation index, the pros and cons of these schemes are determined. The model is used to optimize and select the filling station scheme for a certain mine,the synthetic superior degrees of three optional schemes are obtained, the degrees are 71.2%, 46.4%,56.3%, respectively. Obviously, the first solution is the best. Based on the mine production practice, it is confirmed that the filling station scheme determined by the method has achieved good economic and social benefits.

Conductor Fatigue Strength Decay Rule of EHV Transmission Line

QIN Li;LI Junkuo;FU Qiang;NING Bo
Science & Technology Review. 2013, 31 (19): 44-48. ;  doi: 10.3981/j.issn.1000-7857.2013.19.006
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Abstract ( 224 )
ACSR fatigue failure is the process of injury continuous accumulation and strength gradual decline. The fatigue strength of the ACSR is declining with the number of dynamic load increasing. When the residual strength of the strand is equal to the dynamic bending stress, the ACSR strands are broken. Therefore, the research on residual strength of EHV transmission line has the important significant on fatigue breakdown and injury of ACSR. Based on the non-linear strength degradation model, the structural properties and loading characteristics of EHV transmission lines are considered in order to derive the ACSR residual strength model. And the model parameters are calculated according to the conservative S-N curve of ACSR formulated by CIGRE. The feasibility of the residual strength model is proved through the analysis on different examples. The research shows that the relationship between the degradation degree of conductor strength and loading times is non-linear. The strength decay rates are different with different loadings. The amount of conductor strength attenuation is positively correlated with the intensity of conductor vibration as well as the duration of vibration; with the same load, the decay rate of ACSR strength is increasing with loading times increasing.

Application of ANP Fuzzy Comprehensive Evaluation to the Operation of Underground Scraper

JIA Mingtao;LI Xiaomei;WU Lichun
Science & Technology Review. 2013, 31 (19): 49-52. ;  doi: 10.3981/j.issn.1000-7857.2013.19.007
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Abstract ( 179 )
Scientific and objective evaluation on the safety operation of underground mine scraper is able to effectively reduce the probability of accidents caused by personnel, equipment, environment, and management factors, improve the safety level of underground mine scraper operation. An ANP fuzzy comprehensive evaluation method is applied, and the personnel, equipment, and management system involving the scraper operation are taken as the research subject. A systematic analysis on various safety elements concerning the scraper operation is conducted and the practical situation of certain metal mine is combined with. Then an overall evaluation index system for the scraper operation is established, and the weights for the indexes of first and second classes are determined. The results of fuzzy comprehensive evaluation indicate that the operation of target layer-underground mine scraper is unsafe and appropriate measures need to be take in order to reduce the risk factors of dangers. The research results verify that the method is both scientific and effective, and is able to be applied to the risk control and management concerning underground scraper operation.

Experimental Study on the Removal of Benzene and Xylene Contained in Groundwater by Biosparging Technology

ZHANG Fengjun;JIA Han;LI Chenyang;MENG Qingling;ZHAO Jing;LÜCong
Science & Technology Review. 2013, 31 (19): 53-57. ;  doi: 10.3981/j.issn.1000-7857.2013.19.008
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Abstract ( 503 )
Based on the hydrogeological characteristics of field site contaminated by the petroleum in the Northeast of China, the effects of environmental factors on the growth of microorganisms and the biodegradation of benzene and xylene are investigated by batch experiment. Also, the migration rules for microorganisms in different sandy media and the biodegradation of benzene and xylene using biosparging are carried out by column experiment. The results indicate that the optimal condition for the biodegradation of benzene and xylene is as follows: the temperature is 20℃, pH value is 7.0, nitrogen and phosphorus added and DO is 5.21mg/L. The migration velocity of microorganisms increases with the diameter and porosity of the media increasing. For one kind of medium, the time for microorganism penetrating first medium of 20cm is longer than last medium of 20cm. For different media, the time taken by microorganisms to penetrate the medium of 40cm is in an ascendant order, namely, gravelly sand<coarse sand<medium sand. Generally speaking, with the diameter of the media decreasing, the removal rate of benzene and xylene increases and in the medium of medium sandy, the removal rate reaches at above 40% by biosparging.

Design and Implementation of Distributed Electric Power Quality Information System

ZHAO Xia;LIN Tianhua
Science & Technology Review. 2013, 31 (19): 58-61. ;  doi: 10.3981/j.issn.1000-7857.2013.19.009
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Abstract ( 171 )
Distributed Power Quality Information System (DPQIS) adopts the distributed technology to design and implementation the Power Quality Information System (PQIS). The construction of power quality online monitoring system is an important method for improving the quality of electricity and ensuring the safe supply of power grid. The conventional PQIS includes the following subsystems, such as data collection, data computation, and data analysis. With the number of monitoring sites rapidly increase, the load of the above subsystems increases multiply. Due to the processing ability limitation of the system, the number of monitoring sites of the system is limited. The performance bottleneck of the system should be solved urgently. The distributed architecture is employed to design, utilize distributed processing system for the data collection, the distributed database is used for data storage, distributed computing is taken for data computation, and WebService interface is adopted for encapsulating data access; the processing ability and response speed of the system are economically and effectively improved. Then the upper limit problem of server load is resolved and the demand on massively increasing monitoring sites for electric supply company in the future is satisfied.

Preparation of MgNb2O6 Powders by Using High-energy Ball-milling Method and Properties of MgNb2O6 Ceramics

FU Zhifen;MA Jianli;GAO Juan;LIU Peng
Science & Technology Review. 2013, 31 (19): 62-65. ;  doi: 10.3981/j.issn.1000-7857.2013.19.010
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Abstract ( 273 )
By using high-energy ball-milling method, MgNb2O6 powders were synthesized at 800℃ for 2h. Meanwhile, phase transition, sintering behavior, microstructures, and microwave dielectric properties of MgNb2O6 ceramics changing with sintering tempreature were investigated. It is found that the calcining temperature of MgNb2O6 powders and the sintering temperature of MgNb2O6 ceramic are able to be effectively reduced. The pottery of MgNb2O6 sintered at 1,220℃ for 2h possesses the average grain size of 3.5μm, ρ= 4.80g/cm3, and excellent microwave dielectric properties of r=19.7 and quality factor Q·f=29,444GHz. Therefore, MgNb2O6 pottery obtained by the high energy ball-milling method makes itself become an appropriate candidate for the new generation of middle-temperature sintered high frequency microwave dielectric material.
Reviews

Overview on Epigenetics and Its Progress

KANG Jingting;LIANG Qianjin;LIANG Chen;WANG Pengcheng
Science & Technology Review. 2013, 31 (19): 66-74. ;  doi: 10.3981/j.issn.1000-7857.2013.19.011
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Abstract ( 369 )
Epigenetic regulation modes, epigenetic regulatory effects, and the research progresses in plant epigenetic are summarized. According to classical genetics, nucleic acids are the foundation of heredity, and the hereditary information of life is stored in the base sequence of nucleic acids. The change of base sequence might lead to phenotypic variations of organisms, and these variations might pass on to the next generation. Within one organism, the different types of cells have their own unique gene expression patterns, although they share the same genetic background. It is caused by activating some special sets of genes, meanwhile suppressing the other. This phenomenon is known as epigenetic modification. Epigenetics is a phenomenon for altering gene expression pattern; however changes in the underlying DNA sequence of the gene are not involved. Its process includes DNA methylation, histone modification, and non-coding RNA regulation, etc. Its manifestation includes genomic imprinting, maternal effect, gene silencing, nucleoli dominance, and dormant transposon activation, etc. Epigenetic modification is the result of interactions between environmental factors and intracellular genetic materials. Through gene expression regulation, epigenetic modification is able to control the phenotype of an organism. Due to its importance for maintaining stable environment inside an organism and normal functions of organs, abnormal epigenetic modification could lead to disease. It is why today epigenetics becomes a hot research spot on the drug design and therapy development.

Worldwide BASIC Situation Analysis on Occupational Radiation Exposures of Nuclear Fuel Cycle

QIAO Yahua;FU Zhiwei;CHEN Haiying;ZHANG Chunming
Science & Technology Review. 2013, 31 (19): 75-79. ;  doi: 10.3981/j.issn.1000-7857.2013.19.012
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Abstract ( 175 )
The International Labour Organization and the International Basic Safety Standards define occupational exposure as "all exposure of workers incurred in the course of their work, with the exception of exposure excluded from the standards and exposures from practices or sources exempted by the standards". Various national authorities or institutions have used different methods to measure, record, and report the occupational data. The occupational radiation exposures in nuclear fuel cycle at the worldwide levels, which involve the uranium mining and milling, uranium conversion and enrichment, fuel component fabrication, operation of nuclear reactors, fuel reprocessing, and radiative waste management, are provided (data end up at 2004). The five-year average exposures beginning with 1975 has been evaluated. These data originate from the (OECD/NEA) database, the UNSCEAR, and ISOE of IAEA. The data assessment methodology of dose is described, and the occupational radiation exposures in nuclear fuel cycle are analyzed. The results show that in the each link of nuclear fuel cycle, the occupational radiation exposures of uranium mining is maximum, following by the uranium enrichment and conversion as well as nuclear fuel fabrication. In the period of 1975—2004, the trends of total level occupational exposures has decreased, especially after the 1990s, the average effective doses have been decreased significantly, the safety and health of workers has been effectively assured.
书评

Science & Technology Review. 2013, 31 (19): 80-80. ;  doi:
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Abstract ( 98 )
主编心语

Science & Technology Review. 2013, 31 (19): 83-83. ;  doi:
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Abstract ( 126 )
科技纵横捭阖

Science & Technology Review. 2013, 31 (19): 84-84. ;  doi:
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Abstract ( 93 )
科技职场

Science & Technology Review. 2013, 31 (19): 85-85. ;  doi:
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Abstract ( 140 )

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