The reactivation of trace elements in source rocks is fundamental in the formation of many economic deposits. Although transport by fluid flow and infiltration is very effective along visible fractures, the migration ...The reactivation of trace elements in source rocks is fundamental in the formation of many economic deposits. Although transport by fluid flow and infiltration is very effective along visible fractures, the migration of trace elements from the inner part of solid cells to the weaknesses is much less efficient, and so becomes the bottleneck in the migration of these elements from their initial positions in the source rock to the final deposition site in an ore body. Diffusion may play a key role in the reactivation of trace elements. The overall migration pattern of trace elements in source rocks is characterized by an embedded sink mosaic structure, which possesses the self-similarity of a fractal. There are two general migration tendencies of trace elements. One is from within solid cells, such as mineral grains, toward the sink, consisting of weaknesses in the source rock. The other is from high-temperature fields toward low-temperature ones. High temperature favors the realization of these two tendencies. Conjugate geochemical anomalies are the inevitable result of a closed system.展开更多
Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ...Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures.展开更多
基金This study was funded by Canadian International Development Agency, Excellence-selecting Grant for Go-Abroad Fellows of the Chinese Academy of Sciences and the Open Laboratory of Ore Deposit Geochemistry affiliated to the Chinese Academy of Sciences.
文摘The reactivation of trace elements in source rocks is fundamental in the formation of many economic deposits. Although transport by fluid flow and infiltration is very effective along visible fractures, the migration of trace elements from the inner part of solid cells to the weaknesses is much less efficient, and so becomes the bottleneck in the migration of these elements from their initial positions in the source rock to the final deposition site in an ore body. Diffusion may play a key role in the reactivation of trace elements. The overall migration pattern of trace elements in source rocks is characterized by an embedded sink mosaic structure, which possesses the self-similarity of a fractal. There are two general migration tendencies of trace elements. One is from within solid cells, such as mineral grains, toward the sink, consisting of weaknesses in the source rock. The other is from high-temperature fields toward low-temperature ones. High temperature favors the realization of these two tendencies. Conjugate geochemical anomalies are the inevitable result of a closed system.
文摘Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures.
