Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding （MIM）. The prediction of segregation in MIM requires a bi-phase flow model to describe ...Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding （MIM）. The prediction of segregation in MIM requires a bi-phase flow model to describe distinctly the flows of metallic powder and polymer binder. Viscous behaviors for the flows of each phase should hence be determined. The coefficient of interaction between the flows of two phases should also be evaluated. However, only viscosity of the mixed feedstock is measurable by capillary tests. Wall sticking is supposed in the traditional model for capillary tests, while the wall slip is important to be taken into account in MIM injection. Objective of the present paper is to introduce the slip effect in bi-phase simulation, and search the suitable way to determine the viscous behaviors for each phase with the consideration of wall slip in capillary tests. Analytical and numerical methods were proposed to realize such a specific purpose. The proposed method is based on the mass conservation between the capillary flows in mono-phase model for the mixed feedstock and in bi-phase model for the flows of two phases. Examples of the bi-phase simulation in MIM were realized with the software developed by research team. The results show evident segregation, which is valuable for improving the mould designs.展开更多
All-optical format conversion between non-return-to-zero(NRZ)and the Manchester code is implemented by using an optical exclusive-OR(XOR)logic gate based on a semiconductor optical amplifier Mach-Zehnder Interferomete...All-optical format conversion between non-return-to-zero(NRZ)and the Manchester code is implemented by using an optical exclusive-OR(XOR)logic gate based on a semiconductor optical amplifier Mach-Zehnder Interferometer(SOA-MZI).There is 10 Gbit/s all-optical NRZ-to-Manchester conversion implemented in our simulation system and BER performance of the format conversion is investigated.Transmission performances of the converted Manchester coded signal are discussed in terms of transmission length and received optical power.展开更多
基金Specialized Research Fund for the Doc-toral Program of Higher Education (No.20020613005)
文摘Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding （MIM）. The prediction of segregation in MIM requires a bi-phase flow model to describe distinctly the flows of metallic powder and polymer binder. Viscous behaviors for the flows of each phase should hence be determined. The coefficient of interaction between the flows of two phases should also be evaluated. However, only viscosity of the mixed feedstock is measurable by capillary tests. Wall sticking is supposed in the traditional model for capillary tests, while the wall slip is important to be taken into account in MIM injection. Objective of the present paper is to introduce the slip effect in bi-phase simulation, and search the suitable way to determine the viscous behaviors for each phase with the consideration of wall slip in capillary tests. Analytical and numerical methods were proposed to realize such a specific purpose. The proposed method is based on the mass conservation between the capillary flows in mono-phase model for the mixed feedstock and in bi-phase model for the flows of two phases. Examples of the bi-phase simulation in MIM were realized with the software developed by research team. The results show evident segregation, which is valuable for improving the mould designs.
基金Supported by the National Natural Science Foundation of China under Grant No 60977002.
文摘All-optical format conversion between non-return-to-zero(NRZ)and the Manchester code is implemented by using an optical exclusive-OR(XOR)logic gate based on a semiconductor optical amplifier Mach-Zehnder Interferometer(SOA-MZI).There is 10 Gbit/s all-optical NRZ-to-Manchester conversion implemented in our simulation system and BER performance of the format conversion is investigated.Transmission performances of the converted Manchester coded signal are discussed in terms of transmission length and received optical power.
