Refractory high-entropy alloys(RHEAs)are emerging as new materials for high temperature structural applications because of their stable mechanical and thermal properties at temperatures higher than 2273 K.In this stud...Refractory high-entropy alloys(RHEAs)are emerging as new materials for high temperature structural applications because of their stable mechanical and thermal properties at temperatures higher than 2273 K.In this study,the mechanical properties of MoNbTaTiW RHEA are examined by applying calculations based on first-principles density functional theory(DFT)and using a large unit cell with 100 randomized atoms.The phase calculation of MoNbTaTiW with CALPHAD method shows the existence of a stable body-centered cubic structure at a high temperature and a hexagonal closely packed phase at a low temperature.The predicted phase,shear modulus,Young’s modulus,Poisson’s ratio,and hardness values are consistent with available experimental results.The linear thermal expansion coefficient,vibrational entropy,and vibrational heat capacity of MoNbTaTiW RHEA are investigated in accordance with Debye-Grüneisen theory.These results may provide a basis for future research related to the application of RHEAs.展开更多
Dear Editor,The field of gut microbiota is progressing rapidly and thus,appellations like the last human organ,a separate organ,a forgotten organ,and a new organ have been applied to gut microbiota to emphasize its vi...Dear Editor,The field of gut microbiota is progressing rapidly and thus,appellations like the last human organ,a separate organ,a forgotten organ,and a new organ have been applied to gut microbiota to emphasize its vital functions in our body(Chang and Kao,2019).Gut microbiota has been shown to play a central role in the regulation of human lipid metabolism and be associated with lipid metabolism disorders when aberrant,through composition and microbial metabolites.展开更多
The lipid droplet （LD） is a unique multi-functional orga- nelle that contains a neutral lipid core covered with a phospholipid monolayer membrane. The LDs have been found in almost all organisms from bacteria to hum...The lipid droplet （LD） is a unique multi-functional orga- nelle that contains a neutral lipid core covered with a phospholipid monolayer membrane. The LDs have been found in almost all organisms from bacteria to humans with similar shape. Several conserved functions of LDs have been revealed by recent studies, including lipid metabolism and trafficking, as well as nucleic acid binding and protection. We summarized these findings and proposed a hypothesis that the LD is a conserved organelle.展开更多
基金the NSF EPSCoR CIMM project under the award#OIA-1541079 and DoD support under the W911NF1910005 contractComputational simulations were supported by the Louisiana Optical Network Infrastructure(LONI)with the supercomputer allocation loni_mat_bio12.
文摘Refractory high-entropy alloys(RHEAs)are emerging as new materials for high temperature structural applications because of their stable mechanical and thermal properties at temperatures higher than 2273 K.In this study,the mechanical properties of MoNbTaTiW RHEA are examined by applying calculations based on first-principles density functional theory(DFT)and using a large unit cell with 100 randomized atoms.The phase calculation of MoNbTaTiW with CALPHAD method shows the existence of a stable body-centered cubic structure at a high temperature and a hexagonal closely packed phase at a low temperature.The predicted phase,shear modulus,Young’s modulus,Poisson’s ratio,and hardness values are consistent with available experimental results.The linear thermal expansion coefficient,vibrational entropy,and vibrational heat capacity of MoNbTaTiW RHEA are investigated in accordance with Debye-Grüneisen theory.These results may provide a basis for future research related to the application of RHEAs.
基金supported by the National Natural Science Foundation of China(Grant Nos.91857201 and 91954108)the Ministry of Science and Technology of the People's Republic of China(Grant Nos.2018YFA0800700,2018YFA0800900).
文摘Dear Editor,The field of gut microbiota is progressing rapidly and thus,appellations like the last human organ,a separate organ,a forgotten organ,and a new organ have been applied to gut microbiota to emphasize its vital functions in our body(Chang and Kao,2019).Gut microbiota has been shown to play a central role in the regulation of human lipid metabolism and be associated with lipid metabolism disorders when aberrant,through composition and microbial metabolites.
文摘The lipid droplet （LD） is a unique multi-functional orga- nelle that contains a neutral lipid core covered with a phospholipid monolayer membrane. The LDs have been found in almost all organisms from bacteria to humans with similar shape. Several conserved functions of LDs have been revealed by recent studies, including lipid metabolism and trafficking, as well as nucleic acid binding and protection. We summarized these findings and proposed a hypothesis that the LD is a conserved organelle.
