Riding mining'' is a form of mining where the working face is located above the roadway and advances parallel to it. Riding mining in deep soft rock creates a particular set of problems in the roadway that include high stresses, large deformations, and support difficulties. Herein we describe a study of the rock deformation mechanism of a roadway as observed during riding mining in deep soft rock. Theoretical analysis, numerical simulations, and on site monitoring were used to examine this problem. The stress in the rock and the visco-elastic behavior of the rock are considered. Real time data, recorded over a period of 240 days, were taken from a 750 transportation roadway. Stress distributions in the rock surrounding the roadway were studied by comparing simulations to observations from the mine. The rock stress shows dynamic behavior as the working face advances. The pressure increases and then drops after peaking as the face advances. Both elastic and plastic deformation of the surrounding rock occurs. Plastic deformation provides a mechanism by which stress in the rock relaxes due to material flow. A way to rehabilitate the roadway is suggested that will help ensure mine safety. (C) 2012 Published by Elsevier B.V. on behalf of China University of Mining & Technology. [Zhao Guozhen; Ma Zhanguo; Mao Xianbiao; Feng Meimei] China Univ Min & Technol, State Key Lab Geomech & Deep Underground Engn, Xuzhou 221008, Peoples R China; [Zhao Guozhen; Ma Zhanguo; Mao Xianbiao; Feng Meimei] China Univ Min & Technol, Sch Mech & Civil Engn, Xuzhou 221008, Peoples R China; [Zhu Qinghua] Zhangshuanglou Mine Xuzhou Mine Grp, Xuzhou 221616, Peoples R China China University of Mining & Technology; China University of Mining & Technology Zhao, GZ (corresponding author), China Univ Min & Technol, State Key Lab Geomech & Deep Underground Engn, Xuzhou 221008, Peoples R China. zhaoguozhen@yahoo.com National Natural Science Foundation of China [50834005, 51074163]; Ministry of Education Support Program for New Century Excellent of China [NCET-08-0837]; Fundamental Research Funds for the Central Universities of China; Youth Science and Technology Foundation of China University of Mining and Technology [2010QNB25] National Natural Science Foundation of China(National Natural Science Foundation of China (NSFC)); Ministry of Education Support Program for New Century Excellent of China; Fundamental Research Funds for the Central Universities of China(Fundamental Research Funds for the Central Universities); Youth Science and Technology Foundation of China University of Mining and Technology This study is Supported by the National Natural Science Foundation of China (Nos. 50834005 and 51074163), the Ministry of Education Support Program for New Century Excellent of China (No. NCET-08-0837), and the Fundamental Research Funds for the Central Universities of China, and Youth Science and Technology Foundation of China University of Mining and Technology (No. 2010QNB25). 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J. Min. Sci. Technol. JUL 2012 22 4 539 544 10.1016/j.ijmst.2012.01.017 http://dx.doi.org/10.1016/j.ijmst.2012.01.017 6 Mining & Mineral Processing Emerging Sources Citation Index (ESCI) Mining & Mineral Processing V6S9P 2023-03-22 WOS:000420586400017
J Zhao, H Zhao Hong China's Dilemma on Iran and its Options EAST ASIAN POLICY English Article Iran is China's third largest oil supply country and an important destination of China's FDI. As US-led sanctions on Iran tighten, China faces increasing pressure to adjust its policies on Iran. China is caught between its extensive commercial relations with Iran and its desire to be recognised as a big responsible country. [Zhao Hong] Natl Univ Singapore, East Asian Inst, Singapore, Singapore National University of Singapore Zhao, H (corresponding author), Natl Univ Singapore, East Asian Inst, Singapore, Singapore. 0 0 0 0 0 WORLD SCIENTIFIC PUBL CO PTE LTD SINGAPORE 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE 1793-9305 2251-3175 EAST ASIAN POLICY East Asian Policy JUL-SEP 2012 4 3 64 77 10.1142/S179393051200027X http://dx.doi.org/10.1142/S179393051200027X 14 Political Science Emerging Sources Citation Index (ESCI) Government & Law VD3HB 2023-03-22 WOS:000436658000007
J Zhou, LJ; He, XX; Li, K Zhou, Lijuan; He, Xiaoxu; Li, Kang An Improved Approach for Materialized View Selection Based on Genetic Algorithm JOURNAL OF COMPUTERS English Article data warehouse; materialized view selection; genetic algorithms; evolutionary stagnation; invalid solution This paper presents an improved genetic algorithm to solve the materialized view selection problem under query cost constraints. The algorithm dynamically changes the crossover probability and mutation probability in the process of genetic. In this way, it can not only maintain the population diversity, but also ensure the convergence of the genetic algorithm. So it effectively improves the optimization ability of genetic algorithm, thus avoiding the evolutionary stagnation" problems. Meanwhile, the improved genetic algorithm increases the processing of invalid solution to avoid the "evolutionary stagnation" problems generated by invalid cycle, thereby the efficiency of materialized view selection is greatly improved.
