Coal bump is a dynamic process,thus it is necessary to reveal the process validly.2D-ball code is an efficient approach developed by the authors based on the basicDEM rationale proposed by Cundall.Numerical simulation...Coal bump is a dynamic process,thus it is necessary to reveal the process validly.2D-ball code is an efficient approach developed by the authors based on the basicDEM rationale proposed by Cundall.Numerical simulations show that the coal bump experiencesa process of energy accumulation,sudden release of energy and energy decrease.The stiffness of coal particles has a great influence on the coal bump morphosisand particle velocity.Generally,the larger the stiffness of particles,the longer the shootingoff period and the larger the bump velocity.This is in agreement with the results of laboratoryexperiment and in-situ studies.However,the stiffness of particles has an influence onthe quantity value energy and no influence on the releasing energy pattern of the coalbump.展开更多
The maximum of g2-d2 for linear [n, k, d; q] codes C is studied. Here d2 is the smallest size of the support of 2-dimensional subcodes of C and g2 is the smallest size of the support of 2-dimensional subcodes of C whi...The maximum of g2-d2 for linear [n, k, d; q] codes C is studied. Here d2 is the smallest size of the support of 2-dimensional subcodes of C and g2 is the smallest size of the support of 2-dimensional subcodes of C which contains a codeword of weight d. The extra cost to the greedy adversary to get two symbols of information using some algorithm is g2-d2. For codes satisfying the fullrank condition of general dimensions, upper bounds on the maximum of g2-d2 are given. Under some condition we have got code C where g2-d2 reaches the upper bound.展开更多
基金Supported by the National Natural Science Fundation of China(50534080,50674063)Taishan Scholar Engineering Construction Fund of Shandong Province of China(J06N04)
文摘Coal bump is a dynamic process,thus it is necessary to reveal the process validly.2D-ball code is an efficient approach developed by the authors based on the basicDEM rationale proposed by Cundall.Numerical simulations show that the coal bump experiencesa process of energy accumulation,sudden release of energy and energy decrease.The stiffness of coal particles has a great influence on the coal bump morphosisand particle velocity.Generally,the larger the stiffness of particles,the longer the shootingoff period and the larger the bump velocity.This is in agreement with the results of laboratoryexperiment and in-situ studies.However,the stiffness of particles has an influence onthe quantity value energy and no influence on the releasing energy pattern of the coalbump.
基金This paper was presented at International Congress of Mathematicians,August 20-28,2002,BeijingThis work was supported by the Norwegian Research Council and the National NaturalScience Foundation of China(GrantNo.10271116).
文摘The maximum of g2-d2 for linear [n, k, d; q] codes C is studied. Here d2 is the smallest size of the support of 2-dimensional subcodes of C and g2 is the smallest size of the support of 2-dimensional subcodes of C which contains a codeword of weight d. The extra cost to the greedy adversary to get two symbols of information using some algorithm is g2-d2. For codes satisfying the fullrank condition of general dimensions, upper bounds on the maximum of g2-d2 are given. Under some condition we have got code C where g2-d2 reaches the upper bound.