The effect of a rotating magnetic field(RMF)on the distribution of Al_(2)O_(3)particles with an Al melt was studied by means of simulation and experiment.The results show that Al_(2)O_(3)particles(diameter of 1-10μm,...The effect of a rotating magnetic field(RMF)on the distribution of Al_(2)O_(3)particles with an Al melt was studied by means of simulation and experiment.The results show that Al_(2)O_(3)particles(diameter of 1-10μm,1wt.%)are significantly agglomerated at the top of ingots when subjected to an RMF,and their distribution is influenced by both the intensity and the duration of RMF application.The optimal separation efficiency is achieved with the magnetic intensity of 12 mT for 120 s.The number of the particles at the bottom and the middle decreases by 64.5%and 69.7%,respectively,while that at the top increases by 242.5%compared to the condition without an RMF.However,if further increase the intensity or the duration of RMF,it can induce turbulent flows that draw some of the separated Al_(2)O_(3)particles back into the melt,reducing separation efficiency.The calculation results show that as the magnetic intensity increases from 6 mT to 18 mT,the velocity difference between the particles and the Al melt flow quadruples,increasing from 0.013 m·s^(-1)to 0.066 m·s^(-1).Driven by this velocity difference,centrifugal motion,and secondary circulation,Al_(2)O_(3)particles tend to migrate upwards within the melt,facilitating the separation of impurity particles and enhancing the purity of the melt.展开更多
In recent years,natural orifice specimen extraction surgery(NOSES)in the treatment of colorectal cancer has attracted widespread attention.The potential benefits of NOSES including reduction in postoperative pain and ...In recent years,natural orifice specimen extraction surgery(NOSES)in the treatment of colorectal cancer has attracted widespread attention.The potential benefits of NOSES including reduction in postoperative pain and wound complications,less use of postoperative analgesic,faster recovery of bowel function,shorter length of hospital stay,better cosmetic and psychological effect have been described in colorectal surgery.Despite significant decrease in surgical trauma of NOSES have been observed,the potential pitfalls of this technique have been demonstrated.Particularly,several issues including bacteriological concerns,oncological outcomes and patient selection are raised with this new technique.Therefore,it is urgent and necessary to reach a consensus as an industry guideline to standardize the implementation of NOSES in colorectal surgery.After three rounds of discussion by all members of the International Alliance of NOSES,the consensus is finally completed,which is also of great significance to the long-term progress of NOSES worldwide.展开更多
Structural, electronic properties and mechanical anisotropy of Amm2-carbon are investigated utilizing tlrst-principles calculations by Oambridge Serial Total Energy Package （CASTEP） code. The work is performed with ...Structural, electronic properties and mechanical anisotropy of Amm2-carbon are investigated utilizing tlrst-principles calculations by Oambridge Serial Total Energy Package （CASTEP） code. The work is performed with the generalized gradient approximation in the form of Perdew Burke-Ernzerhof （PBE）, PBEsol, Wu and Cohen （WC） and local density approximation in the form of Ceperley and Alder data as parameterized by Perdew and Zunger （CA-PZ）. The mechanical anisotropy eMculations show that Amm2-carbon exhibit large anisotropy in elastic moduli, such as Poisson＇s ratio, shear modulus and Young＇s modulus, and other anisotropy factors, such as the shear anisotropic factor and the universal anisotropic index AU. It is interestingly that the anisotropy in shear modulus and Young＇s modulus, universal anisotropic index and the shear anisotropie factor all increases with increasing pressure, but the anisotropy in Poisson＇s ratio decreases. The band structure calculations reveal that Amm2-carbon is a direct-band-gap semiconductor at ambient pressure, but with the pressure increasing, it becomes an indirect-band-gap semiconductor.展开更多
基金support of the National Natural Science Foundation of China(Nos.52171135 and 51971048).
文摘The effect of a rotating magnetic field(RMF)on the distribution of Al_(2)O_(3)particles with an Al melt was studied by means of simulation and experiment.The results show that Al_(2)O_(3)particles(diameter of 1-10μm,1wt.%)are significantly agglomerated at the top of ingots when subjected to an RMF,and their distribution is influenced by both the intensity and the duration of RMF application.The optimal separation efficiency is achieved with the magnetic intensity of 12 mT for 120 s.The number of the particles at the bottom and the middle decreases by 64.5%and 69.7%,respectively,while that at the top increases by 242.5%compared to the condition without an RMF.However,if further increase the intensity or the duration of RMF,it can induce turbulent flows that draw some of the separated Al_(2)O_(3)particles back into the melt,reducing separation efficiency.The calculation results show that as the magnetic intensity increases from 6 mT to 18 mT,the velocity difference between the particles and the Al melt flow quadruples,increasing from 0.013 m·s^(-1)to 0.066 m·s^(-1).Driven by this velocity difference,centrifugal motion,and secondary circulation,Al_(2)O_(3)particles tend to migrate upwards within the melt,facilitating the separation of impurity particles and enhancing the purity of the melt.
文摘In recent years,natural orifice specimen extraction surgery(NOSES)in the treatment of colorectal cancer has attracted widespread attention.The potential benefits of NOSES including reduction in postoperative pain and wound complications,less use of postoperative analgesic,faster recovery of bowel function,shorter length of hospital stay,better cosmetic and psychological effect have been described in colorectal surgery.Despite significant decrease in surgical trauma of NOSES have been observed,the potential pitfalls of this technique have been demonstrated.Particularly,several issues including bacteriological concerns,oncological outcomes and patient selection are raised with this new technique.Therefore,it is urgent and necessary to reach a consensus as an industry guideline to standardize the implementation of NOSES in colorectal surgery.After three rounds of discussion by all members of the International Alliance of NOSES,the consensus is finally completed,which is also of great significance to the long-term progress of NOSES worldwide.
基金Supported by the National Natural Science Foundation of China under Grant No.61564005
文摘Structural, electronic properties and mechanical anisotropy of Amm2-carbon are investigated utilizing tlrst-principles calculations by Oambridge Serial Total Energy Package （CASTEP） code. The work is performed with the generalized gradient approximation in the form of Perdew Burke-Ernzerhof （PBE）, PBEsol, Wu and Cohen （WC） and local density approximation in the form of Ceperley and Alder data as parameterized by Perdew and Zunger （CA-PZ）. The mechanical anisotropy eMculations show that Amm2-carbon exhibit large anisotropy in elastic moduli, such as Poisson＇s ratio, shear modulus and Young＇s modulus, and other anisotropy factors, such as the shear anisotropic factor and the universal anisotropic index AU. It is interestingly that the anisotropy in shear modulus and Young＇s modulus, universal anisotropic index and the shear anisotropie factor all increases with increasing pressure, but the anisotropy in Poisson＇s ratio decreases. The band structure calculations reveal that Amm2-carbon is a direct-band-gap semiconductor at ambient pressure, but with the pressure increasing, it becomes an indirect-band-gap semiconductor.
