Semisolid rheoforming （SSR） is a promising technology for the production of Mg wrought alloy in foundry settings. In order to realize SSR, it is necessary to characterize the grain structure evolution during slurry ...Semisolid rheoforming （SSR） is a promising technology for the production of Mg wrought alloy in foundry settings. In order to realize SSR, it is necessary to characterize the grain structure evolution during slurry preparation. In this paper, slurry of AZ31 alloy was produced by a novel rheocast process known as self-inoculation method （SIM）. Interrupted quenching technology was applied to investigate the primary a-Mg evolution during continuous cooling and isothermal holding. Results indicate that the initial microstructure of slurry produced by SIM is a mixture of irregular grains, which becomes ideally globular when the slurry slowly cools to 620 ~C and isothermally held for at least 30 s. The local solute diffusion leads to dendritic fragmentation and forms separated particles. During prolonged holding, the particle surface gradually becomes smooth because of protuberance melting and groove advancement. Coarsening of a-Mg grains in isothermal holding was analyzed using Lifshitz-Slyozov-Wagner theory. Results suggest that coalescence is most likely the dominant coarsening mechanism in the early stage while Ostwald ripening tends to be the principal one later. The EDS results indicate that a longer holding time leads to AI solute element segregation at the grain boundaries, but Zn distribution within liquid matrix has no obvious change.展开更多
The cancer stem cell(CSC)theory is gaining increasing attention from researchers and has become an important focus of cancer research.According to the theory,a minority population of cancer cells is capable of self-re...The cancer stem cell(CSC)theory is gaining increasing attention from researchers and has become an important focus of cancer research.According to the theory,a minority population of cancer cells is capable of self-renewal and generation of differentiated progeny,termed cancer stem cells(CSCs).Understanding the properties and characteristics of CSCs is key to future study on cancer research,such as the isolation and identification of CSCs,the cancer diagnosis,and the cancer therapy.Standard oncology treatments,such as chemotherapy,radiotherapy and surgical resection,can only shrink the bulk tumor and the tumor tends to relapse.Thus,therapeutic strategies that focus on targeting CSCs and their microenvironmental niche address the ineffec-tiveness of traditional cancer therapies to eradicate the CSCs that otherwise result in therapy resistance.The combined use of traditional therapies with targeted CSC-specific agents may target the whole cancer and offer a promising strategy for lasting treatment and even cure.展开更多
基金supported by the National Natural Science Foundation of China(50964010)
文摘Semisolid rheoforming （SSR） is a promising technology for the production of Mg wrought alloy in foundry settings. In order to realize SSR, it is necessary to characterize the grain structure evolution during slurry preparation. In this paper, slurry of AZ31 alloy was produced by a novel rheocast process known as self-inoculation method （SIM）. Interrupted quenching technology was applied to investigate the primary a-Mg evolution during continuous cooling and isothermal holding. Results indicate that the initial microstructure of slurry produced by SIM is a mixture of irregular grains, which becomes ideally globular when the slurry slowly cools to 620 ~C and isothermally held for at least 30 s. The local solute diffusion leads to dendritic fragmentation and forms separated particles. During prolonged holding, the particle surface gradually becomes smooth because of protuberance melting and groove advancement. Coarsening of a-Mg grains in isothermal holding was analyzed using Lifshitz-Slyozov-Wagner theory. Results suggest that coalescence is most likely the dominant coarsening mechanism in the early stage while Ostwald ripening tends to be the principal one later. The EDS results indicate that a longer holding time leads to AI solute element segregation at the grain boundaries, but Zn distribution within liquid matrix has no obvious change.
文摘The cancer stem cell(CSC)theory is gaining increasing attention from researchers and has become an important focus of cancer research.According to the theory,a minority population of cancer cells is capable of self-renewal and generation of differentiated progeny,termed cancer stem cells(CSCs).Understanding the properties and characteristics of CSCs is key to future study on cancer research,such as the isolation and identification of CSCs,the cancer diagnosis,and the cancer therapy.Standard oncology treatments,such as chemotherapy,radiotherapy and surgical resection,can only shrink the bulk tumor and the tumor tends to relapse.Thus,therapeutic strategies that focus on targeting CSCs and their microenvironmental niche address the ineffec-tiveness of traditional cancer therapies to eradicate the CSCs that otherwise result in therapy resistance.The combined use of traditional therapies with targeted CSC-specific agents may target the whole cancer and offer a promising strategy for lasting treatment and even cure.
