In the current building HVAC project, designers should have a better pursuit in the optimization of design details. In this paper, according to the author's design experience, the author puts forward practical sol...In the current building HVAC project, designers should have a better pursuit in the optimization of design details. In this paper, according to the author's design experience, the author puts forward practical solutions to some problems often encountered in the HVAC design, in order to optimize some details of the HVAC design project.展开更多
High intensity conditioning(HIC)was used as a model to study the fundamental of fine sulphide particle flotation.The effect of impeller design,mechanical energy input,and agitation speed on aggregate size of fine spha...High intensity conditioning(HIC)was used as a model to study the fundamental of fine sulphide particle flotation.The effect of impeller design,mechanical energy input,and agitation speed on aggregate size of fine sphalerite was tested.The aggregate size of fine sphalerite was measured with the Malvern Hydro 2000 Mastersizer.The results show that the size of aggregates of sphalerite particles ground for 3 min can be enlarged significantly with the activator and collector addition in HIC using the high energy impeller.The improved particle aggregation by using the high energy impeller is not directly related to a higher energy input into the system.With the same energy input into HIC,the aggregate size obtained with the high energy impeller is much coarser than that obtained with the low energy impeller.With the new impeller in HIC,the sphalerite aggregate size decreases with increasing agitation speed from 700 to 2 500 r/min.However,the recovery does not decrease until the agitation speed reaches 2 500 r/min.展开更多
Under normal forging and annealing conditions, there are different ultra fine carbides (M3C, M23C6, M7Cj, M6C and MC) in high carbon alloy steels when alloy composition design is carried out properly. On the basis of ...Under normal forging and annealing conditions, there are different ultra fine carbides (M3C, M23C6, M7Cj, M6C and MC) in high carbon alloy steels when alloy composition design is carried out properly. On the basis of carbides transformation orderliness, the alloy composition design of the high carbon alloy steels is conducted by phase-equilibrium thermodynamic calculation for Fe-Cr-W-Mo-V-C system. The nucleation and growth of new carbides, dissolution of previous partial carbides in these steels during annealing process, all these lead to ultra-fine distribution of carbides. Due to different crystal structures of carbides and different thermodynamics as well dynamics parameters of the carbides dissolution and precipitation, the range of quenching temperature of these steels is widened, and the good temper-resistance is obtained. The characteristics of heat treatment process and microstructure variance, and the carbides transformation for different temperature are explained by the phase-equilibrium component satisfactorily. Their bend and yield strength, flexibility and toughness all are advanced markedly comparing with that of kindred steels. Results of the applications have proved that the microstructure of ultra-fine carbides in these steels played importance roles in the enhancement of edginess and fatigue crack resistance of the die and knives.展开更多
文摘In the current building HVAC project, designers should have a better pursuit in the optimization of design details. In this paper, according to the author's design experience, the author puts forward practical solutions to some problems often encountered in the HVAC design, in order to optimize some details of the HVAC design project.
基金Project(50674103)supported by the National Natural Science Foundation of ChinaProject(2005CB6237601)supported by the NationalBasic Research Program of China
文摘High intensity conditioning(HIC)was used as a model to study the fundamental of fine sulphide particle flotation.The effect of impeller design,mechanical energy input,and agitation speed on aggregate size of fine sphalerite was tested.The aggregate size of fine sphalerite was measured with the Malvern Hydro 2000 Mastersizer.The results show that the size of aggregates of sphalerite particles ground for 3 min can be enlarged significantly with the activator and collector addition in HIC using the high energy impeller.The improved particle aggregation by using the high energy impeller is not directly related to a higher energy input into the system.With the same energy input into HIC,the aggregate size obtained with the high energy impeller is much coarser than that obtained with the low energy impeller.With the new impeller in HIC,the sphalerite aggregate size decreases with increasing agitation speed from 700 to 2 500 r/min.However,the recovery does not decrease until the agitation speed reaches 2 500 r/min.
文摘Under normal forging and annealing conditions, there are different ultra fine carbides (M3C, M23C6, M7Cj, M6C and MC) in high carbon alloy steels when alloy composition design is carried out properly. On the basis of carbides transformation orderliness, the alloy composition design of the high carbon alloy steels is conducted by phase-equilibrium thermodynamic calculation for Fe-Cr-W-Mo-V-C system. The nucleation and growth of new carbides, dissolution of previous partial carbides in these steels during annealing process, all these lead to ultra-fine distribution of carbides. Due to different crystal structures of carbides and different thermodynamics as well dynamics parameters of the carbides dissolution and precipitation, the range of quenching temperature of these steels is widened, and the good temper-resistance is obtained. The characteristics of heat treatment process and microstructure variance, and the carbides transformation for different temperature are explained by the phase-equilibrium component satisfactorily. Their bend and yield strength, flexibility and toughness all are advanced markedly comparing with that of kindred steels. Results of the applications have proved that the microstructure of ultra-fine carbides in these steels played importance roles in the enhancement of edginess and fatigue crack resistance of the die and knives.
