We present a semi-custom design methodology based on transistor tuning to optimize the design performance. Compared with other transistor tuning approaches, our tuning process takes the cross-talk effect into account ...We present a semi-custom design methodology based on transistor tuning to optimize the design performance. Compared with other transistor tuning approaches, our tuning process takes the cross-talk effect into account and prominently reduces the complexity for circuit simulation and analysis by decomposing the circuit network utilizing graph theory. Furthermore, the incremental placement and routing for the corresponding transistor tuning in conventional approaches is not required in our methodology, which might induce timing graph variation and additional iterations for design convergence. This methodology combines the flexible automated circuit tuning and physical design tools to provide more opportunities for design optimization throughout the design cycle.展开更多
Accurate and fast performance estimation is necessary to drive design space exploration and thus support important design decisions. Current techniques are either time consuming or not accurate enough. In this paper, ...Accurate and fast performance estimation is necessary to drive design space exploration and thus support important design decisions. Current techniques are either time consuming or not accurate enough. In this paper, we solve these problems by presenting a hybrid method for multimedia multiprocessor system-on-chip （MPSoC） performance estimation. A general coverage analysis tool GNU gcov is employed to profile the execution statistics during the native simulation. To tackle the complexity and keep the analysis and simulation manageable, the orthogonalization of communication and computation parts is adopted. The estimation result of the computation part is annotated to a transaction accurate model for further analysis, by which a gradual refinement of MPSoC performance estimation is supported. The implementation and its experimental results prove the feasibility and efficiency of the proposed method.展开更多
The microstructures and mechanical properties, especially creep properties, of the NiCrFe-based alloys with various contents of phosphorus and iron were investigated. The results showed that the tensile yield strength...The microstructures and mechanical properties, especially creep properties, of the NiCrFe-based alloys with various contents of phosphorus and iron were investigated. The results showed that the tensile yield strength decreased with increasing iron contents while had no obvious change with the addition of phosphorus. For creep properties, the alloy with15.8 wt% iron and 0.09 wt% phosphorus possessed the longest creep life(679 h) among all alloys. Only M_(23)C_6 was formed in the alloys with low phosphorus contents, while both intergranular M_3P and M_(23)C_6 precipitated with the increment of phosphorus, which enhanced the strength of grain boundary by hindering the movements of dislocations during creep tests. The reasons for the enhancement of creep life were mainly related to the solid solution strengthening effect of phosphorus and optimization of grain boundary precipitations by phosphorus.展开更多
The influence of Fe on the microstructure and mechanical properties of P-doped Ni–Cr–Fe alloys has been investigated.Results showed that increasing Fe content refined the dendrite microstructure and enhanced the sol...The influence of Fe on the microstructure and mechanical properties of P-doped Ni–Cr–Fe alloys has been investigated.Results showed that increasing Fe content refined the dendrite microstructure and enhanced the solubility of P in as-cast alloys.The change of microhardness in different dendrite regions was attributed to the segregation of P atoms in solid solution state,which had strengthening effects.Increasing Fe contents from 15.2 to 60.7 wt%reduced the yield strength and tensile strength but had little influence on the elongation of alloys.The stress rupture life of alloys after heat treatment decreased with the increment of Fe contents,and the failure fracture modes transferred from transgranular to intergranular fracture mode.The change of fracture modes was due to the weakness of grain boundaries caused by the increment of Fe.In addition,the precipitation of M23C6 was believed to be related to the segregation of P toward grain boundaries,which led to the fluctuation of carbon and chromium atoms near the grain boundaries in alloys with low Fe contents.Consequently,the increment of Fe decreased the strength of matrix and changed the existence of P atoms and the precipitates at grain boundaries.展开更多
基金Project (No. 2005AA1Z1271) supported by the Hi-Tech Researchand Development Program (863) of China
文摘We present a semi-custom design methodology based on transistor tuning to optimize the design performance. Compared with other transistor tuning approaches, our tuning process takes the cross-talk effect into account and prominently reduces the complexity for circuit simulation and analysis by decomposing the circuit network utilizing graph theory. Furthermore, the incremental placement and routing for the corresponding transistor tuning in conventional approaches is not required in our methodology, which might induce timing graph variation and additional iterations for design convergence. This methodology combines the flexible automated circuit tuning and physical design tools to provide more opportunities for design optimization throughout the design cycle.
基金Project-supported-- by the National Natural Science Foundation of China （No. 61100074）, the National Science and Technol- ogy Major Project of China （No. 2012ZX01039-004）, and the Fundamental Research Funds for the Central Universities, China
文摘Accurate and fast performance estimation is necessary to drive design space exploration and thus support important design decisions. Current techniques are either time consuming or not accurate enough. In this paper, we solve these problems by presenting a hybrid method for multimedia multiprocessor system-on-chip （MPSoC） performance estimation. A general coverage analysis tool GNU gcov is employed to profile the execution statistics during the native simulation. To tackle the complexity and keep the analysis and simulation manageable, the orthogonalization of communication and computation parts is adopted. The estimation result of the computation part is annotated to a transaction accurate model for further analysis, by which a gradual refinement of MPSoC performance estimation is supported. The implementation and its experimental results prove the feasibility and efficiency of the proposed method.
文摘The microstructures and mechanical properties, especially creep properties, of the NiCrFe-based alloys with various contents of phosphorus and iron were investigated. The results showed that the tensile yield strength decreased with increasing iron contents while had no obvious change with the addition of phosphorus. For creep properties, the alloy with15.8 wt% iron and 0.09 wt% phosphorus possessed the longest creep life(679 h) among all alloys. Only M_(23)C_6 was formed in the alloys with low phosphorus contents, while both intergranular M_3P and M_(23)C_6 precipitated with the increment of phosphorus, which enhanced the strength of grain boundary by hindering the movements of dislocations during creep tests. The reasons for the enhancement of creep life were mainly related to the solid solution strengthening effect of phosphorus and optimization of grain boundary precipitations by phosphorus.
文摘The influence of Fe on the microstructure and mechanical properties of P-doped Ni–Cr–Fe alloys has been investigated.Results showed that increasing Fe content refined the dendrite microstructure and enhanced the solubility of P in as-cast alloys.The change of microhardness in different dendrite regions was attributed to the segregation of P atoms in solid solution state,which had strengthening effects.Increasing Fe contents from 15.2 to 60.7 wt%reduced the yield strength and tensile strength but had little influence on the elongation of alloys.The stress rupture life of alloys after heat treatment decreased with the increment of Fe contents,and the failure fracture modes transferred from transgranular to intergranular fracture mode.The change of fracture modes was due to the weakness of grain boundaries caused by the increment of Fe.In addition,the precipitation of M23C6 was believed to be related to the segregation of P toward grain boundaries,which led to the fluctuation of carbon and chromium atoms near the grain boundaries in alloys with low Fe contents.Consequently,the increment of Fe decreased the strength of matrix and changed the existence of P atoms and the precipitates at grain boundaries.
