Based on the uniaxial compression creep experiments conducted on bauxite sandstone obtained from Sanmenxia,typical creep experiment curves were obtained.From the characteristics of strain component of creep curves,the...Based on the uniaxial compression creep experiments conducted on bauxite sandstone obtained from Sanmenxia,typical creep experiment curves were obtained.From the characteristics of strain component of creep curves,the creep strain is composed of instantaneous elastic strain,ε（me）,instantaneous plastic strain,ε（mp）,viscoelastic strain,ε（ce）,and viscoplastic strain,ε（cp）.Based on the characteristics of instantaneous plastic strain,a new element of instantaneous plastic rheology was introduced,instantaneous plastic modulus was defined,and the modified Burgers model was established.Then identification of direct screening method in this model was completed.According to the mechanical properties of rheological elements,one- and three-dimensional creep equations in different stress levels were obtained.One-dimensional model parameters were identified by the method of least squares,and in the process of computation,Gauss-Newton iteration method was applied.Finally,by fitting the experimental curves,the correctness of direct method model was verified,then the examination of posterior exclusive method of the model was accomplished.The results showed that in the improved Burgers models,the rheological characteristics of sandstone are embodied properly,microscopic analysis of creep curves is also achieved,and the correctness of comprehensive identification method of rheological model is verified.展开更多
In this paper, a new routing algorithm is given for the shuffle-exchange permutation network （SEPn）. The length of the path between any two nodes given by our algorithm is not more than 11/16n^2＋O（n）, i.e., the d...In this paper, a new routing algorithm is given for the shuffle-exchange permutation network （SEPn）. The length of the path between any two nodes given by our algorithm is not more than 11/16n^2＋O（n）, i.e., the diameter of SEPn is at most 11/16n^2＋ O（n）. This improves on a 1/8（9n^2- 22n＋24） routing algorithm described earlier by S. Latifi and P. K. Srimani. We also show that the diameter of SEPn is more than 1/2n^2-n.展开更多
基金Projects (51174228,51274249) supported by the National Natural Science Foundation of China
文摘Based on the uniaxial compression creep experiments conducted on bauxite sandstone obtained from Sanmenxia,typical creep experiment curves were obtained.From the characteristics of strain component of creep curves,the creep strain is composed of instantaneous elastic strain,ε（me）,instantaneous plastic strain,ε（mp）,viscoelastic strain,ε（ce）,and viscoplastic strain,ε（cp）.Based on the characteristics of instantaneous plastic strain,a new element of instantaneous plastic rheology was introduced,instantaneous plastic modulus was defined,and the modified Burgers model was established.Then identification of direct screening method in this model was completed.According to the mechanical properties of rheological elements,one- and three-dimensional creep equations in different stress levels were obtained.One-dimensional model parameters were identified by the method of least squares,and in the process of computation,Gauss-Newton iteration method was applied.Finally,by fitting the experimental curves,the correctness of direct method model was verified,then the examination of posterior exclusive method of the model was accomplished.The results showed that in the improved Burgers models,the rheological characteristics of sandstone are embodied properly,microscopic analysis of creep curves is also achieved,and the correctness of comprehensive identification method of rheological model is verified.
基金This work was supported by the NatLiral Science Foundation of Fujian Provmce(No.Z0511035)the Scientific Research Foundation of Fujian Provincial Education Department(No.JA04249)
文摘In this paper, a new routing algorithm is given for the shuffle-exchange permutation network （SEPn）. The length of the path between any two nodes given by our algorithm is not more than 11/16n^2＋O（n）, i.e., the diameter of SEPn is at most 11/16n^2＋ O（n）. This improves on a 1/8（9n^2- 22n＋24） routing algorithm described earlier by S. Latifi and P. K. Srimani. We also show that the diameter of SEPn is more than 1/2n^2-n.
