The warm powder compaction process is simulated by the finite element analysis software, MSCJMARC. The thermal mechanically coupled analysis method is applied on the basis of the updated Lagrangian Method, to simulate...The warm powder compaction process is simulated by the finite element analysis software, MSCJMARC. The thermal mechanically coupled analysis method is applied on the basis of the updated Lagrangian Method, to simulate the warm powder compaction process. The warm powder compaction process is simulated, and the influence of friction condition and pressing styles are researched on the density of powder green and the mechanics behavior at certain temperature. The results indicate that for cylindrical compacts, with the improvement of the friction condition, the uniformity of distribution of green relative density is largely improved, the pressing force and stress decrease, and the nonconforming pressing processes influence the distribution of green density to some degree. The status of stress distribution of the process that punches firstly press and die finally press is different from the other three processes, and presents the figure of ＇flume ＇.展开更多
We use femtosecond time-resolved optical reflectivity to study the photoexcited quasiparticle(QP)dynamics in the iron-based 112 type superconducting(SC)samples Ca0.82La0.18Fe1-xNixAs2,with x=0 and 0.024.In the parent ...We use femtosecond time-resolved optical reflectivity to study the photoexcited quasiparticle(QP)dynamics in the iron-based 112 type superconducting(SC)samples Ca0.82La0.18Fe1-xNixAs2,with x=0 and 0.024.In the parent sample,a fast and a slow relaxation emerge at temperatures below the magnetic-structure(MS)transition Tms≈50 K and the SC transition Tc≈33 K,respectively.The latter obviously corresponds to an SC QP dynamics,which is further confirmed in the x=0.024 sample with Tc≈25 K.The former suggests that a partial of photoexcited QP relaxation through a pesudogap(PG)channel,which is absent in the doped x=0.024 sample without the MS transition.展开更多
文摘The warm powder compaction process is simulated by the finite element analysis software, MSCJMARC. The thermal mechanically coupled analysis method is applied on the basis of the updated Lagrangian Method, to simulate the warm powder compaction process. The warm powder compaction process is simulated, and the influence of friction condition and pressing styles are researched on the density of powder green and the mechanics behavior at certain temperature. The results indicate that for cylindrical compacts, with the improvement of the friction condition, the uniformity of distribution of green relative density is largely improved, the pressing force and stress decrease, and the nonconforming pressing processes influence the distribution of green density to some degree. The status of stress distribution of the process that punches firstly press and die finally press is different from the other three processes, and presents the figure of ＇flume ＇.
基金Supported by the National Natural Science Foundation of China(Grant Nos.51875009 and 51705006)the Key Project of Beijing Municipal Natural Science Foundation and Beijing Education Committee’s Science and Technology Plan(Grant Nos.KZ201710005004 and KZ201810005001)。
文摘We use femtosecond time-resolved optical reflectivity to study the photoexcited quasiparticle(QP)dynamics in the iron-based 112 type superconducting(SC)samples Ca0.82La0.18Fe1-xNixAs2,with x=0 and 0.024.In the parent sample,a fast and a slow relaxation emerge at temperatures below the magnetic-structure(MS)transition Tms≈50 K and the SC transition Tc≈33 K,respectively.The latter obviously corresponds to an SC QP dynamics,which is further confirmed in the x=0.024 sample with Tc≈25 K.The former suggests that a partial of photoexcited QP relaxation through a pesudogap(PG)channel,which is absent in the doped x=0.024 sample without the MS transition.
