The 4-lobe aluminum alloy helical surface rotors are widely applied in industry,such as superchargers.Generally,the conventional manufacturing processes of aluminum alloy helical surface are time consuming and costly....The 4-lobe aluminum alloy helical surface rotors are widely applied in industry,such as superchargers.Generally,the conventional manufacturing processes of aluminum alloy helical surface are time consuming and costly.To make the manufacturing processes more flexible and economical,the forward hot extrusion process is proposed to form the 4-lobe aluminum alloy helical surface rotors.In this work,we implement both simulations and experiments to the forming process of the helical surface,of which the material is 6063 aluminum alloy.The forward hot extrusion process is simulated with finite element method in DEFORM-3D.Based on the simulation method,the influences of different extrusion parameters,such as extrusion temperature,extrusion speed and extrusion ratio,on the extrusion process are studied.According to the numerical simulation results,the optimal case is chosen to carry out the experiment.Furthermore,the experimental results show that the surface is smooth;the toothed fill is full;the twist angle in the length direction is evenly distributed;the value of twist angle is roughly in line with the design angle,which is mainly due to the modified die structure,having a positive and significant effect on the increment of twist angle.Therefore,the twist angle has an increase of about 76%,which verifies the modified die structure.展开更多
In order to analyze the effect of the spinning triangle on yarn structure,a shape model of the spinning triangle is established.The fiber motion in the spinning triangle can be divided into three stages,and the relati...In order to analyze the effect of the spinning triangle on yarn structure,a shape model of the spinning triangle is established.The fiber motion in the spinning triangle can be divided into three stages,and the relationship between yarn structure and fiber duration as well as the force acting on the fibers in the three stages is analyzed.The fiber elongation in different location of the spinning triangle is variational.The difference is that the elongation of fiber in the middle spinning triangle is bigger than that in the edge of it and the difference will be amplified with the increase of spinning triangle width,which has an effect on the characteristic of yarns structure.Research results for further study on compact yarn structure and improving spinning frame structure provide theory basis.展开更多
转录反式激活因子(trans-activator of transcription,Tat)在HIV-1的转录中起着重要的调控作用,针对HIV-1 Tat中的β-转角结构,采用2H-1,4-苯并二氮-2-酮作为β-转角肽链骨架的模拟结构,分别以对硝基氯苯/苯乙腈、对甲基苯胺/苯甲酰氯...转录反式激活因子(trans-activator of transcription,Tat)在HIV-1的转录中起着重要的调控作用,针对HIV-1 Tat中的β-转角结构,采用2H-1,4-苯并二氮-2-酮作为β-转角肽链骨架的模拟结构,分别以对硝基氯苯/苯乙腈、对甲基苯胺/苯甲酰氯以及硝西泮为起始原料,采用不同合成路线得到了19个2H-1,4-苯并二氮-2-酮类化合物(10～18、21～24、26～31)。初步活性评价表明,化合物30在没有明显细胞毒作用的浓度下对Tat介导的荧光素酶的表达显示了较好的抑制作用,其半数有效浓度EC50为25.0μmol·L-1。展开更多
Twisted trilayer graphene(TLG)may be the simplest realistic system so far,which has flat bands with nontrivial topology.Here,we give a comprehensive calculation about its band structures and the band topology,i.e.,val...Twisted trilayer graphene(TLG)may be the simplest realistic system so far,which has flat bands with nontrivial topology.Here,we give a comprehensive calculation about its band structures and the band topology,i.e.,valley Chern number of the nearly flat bands,with the continuum model.With realistic parameters,the magic angle of twisted TLG is about 1.12°,at which two nearly flat bands appears.Unlike the twisted bilayer graphene,a small twist angle can induce a tiny gap at all the Dirac points,which can be enlarged further by a perpendicular electric field.The valley Chern numbers of the two nearly flat bands in the twisted TLG depends on the twist angleθand the perpendicular electric field E⊥.Considering its topological flat bands,the twisted TLG should be an ideal experimental platform to study the strongly correlated physics in topologically nontrivial flat band systems.And,due to its reduced symmetry,the correlated states in twisted TLG should be quite different from that in twisted bilayer graphene and twisted double bilayer graphene.展开更多
During the evolution of the binary system, many physical processes occur, which can influence the orbital angular velocity and the spin angular velocities of the two components, and influence the non-synchronous or sy...During the evolution of the binary system, many physical processes occur, which can influence the orbital angular velocity and the spin angular velocities of the two components, and influence the non-synchronous or synchronous rotation of the system. These processes include the transfer of masses and angular momentums between the component stars, the loss of mass and angular momentum via stellar winds, and the deformation of the structure of component stars. A study of these processes indicates that they are closely related to the combined effects of tide and rotation. This means, to study the synchronous or non-synchronous rotation of binary systems, one has to consider the contributions of different physical processes simultaneously, instead of the tidal effect alone. A way to know whether the rotation of a binary system is synchronous or non-synchronous is to calculate the orbital angular velocity and the spin angular velocities of the component stars. If all of these angular velocities are equal, the rotation of the system is synchronous. If not, the rotation of the system is non-synchronous. For this aim, a series of equations are developed to calculate the orbital and spin angular velocities. The evolutionary calculation of a binary system with masses of 10M~ ＋ 6Me shows that the transfer of masses and angular momentums between the two components, and the deformation of the components structure in the semidetached or in the contact phase can change the rotation of the system from synchronous into non-synchronous rotation.展开更多
基金Project(zzyjkt2014-09)supported by the National Key Laboratory of High Performance and Complex Manufacturing,ChinaProject(2015GK3006)supported by Key R&D Program of Science and Technology Department of Hunan Province,China
文摘The 4-lobe aluminum alloy helical surface rotors are widely applied in industry,such as superchargers.Generally,the conventional manufacturing processes of aluminum alloy helical surface are time consuming and costly.To make the manufacturing processes more flexible and economical,the forward hot extrusion process is proposed to form the 4-lobe aluminum alloy helical surface rotors.In this work,we implement both simulations and experiments to the forming process of the helical surface,of which the material is 6063 aluminum alloy.The forward hot extrusion process is simulated with finite element method in DEFORM-3D.Based on the simulation method,the influences of different extrusion parameters,such as extrusion temperature,extrusion speed and extrusion ratio,on the extrusion process are studied.According to the numerical simulation results,the optimal case is chosen to carry out the experiment.Furthermore,the experimental results show that the surface is smooth;the toothed fill is full;the twist angle in the length direction is evenly distributed;the value of twist angle is roughly in line with the design angle,which is mainly due to the modified die structure,having a positive and significant effect on the increment of twist angle.Therefore,the twist angle has an increase of about 76%,which verifies the modified die structure.
文摘In order to analyze the effect of the spinning triangle on yarn structure,a shape model of the spinning triangle is established.The fiber motion in the spinning triangle can be divided into three stages,and the relationship between yarn structure and fiber duration as well as the force acting on the fibers in the three stages is analyzed.The fiber elongation in different location of the spinning triangle is variational.The difference is that the elongation of fiber in the middle spinning triangle is bigger than that in the edge of it and the difference will be amplified with the increase of spinning triangle width,which has an effect on the characteristic of yarns structure.Research results for further study on compact yarn structure and improving spinning frame structure provide theory basis.
文摘转录反式激活因子(trans-activator of transcription,Tat)在HIV-1的转录中起着重要的调控作用,针对HIV-1 Tat中的β-转角结构,采用2H-1,4-苯并二氮-2-酮作为β-转角肽链骨架的模拟结构,分别以对硝基氯苯/苯乙腈、对甲基苯胺/苯甲酰氯以及硝西泮为起始原料,采用不同合成路线得到了19个2H-1,4-苯并二氮-2-酮类化合物(10～18、21～24、26～31)。初步活性评价表明,化合物30在没有明显细胞毒作用的浓度下对Tat介导的荧光素酶的表达显示了较好的抑制作用,其半数有效浓度EC50为25.0μmol·L-1。
基金the National Natural Science Foundation of China(11534001,11874160,11274129,11874026,and 61405067)the National Key Research and Development Program of China(2017YFA0403501)+1 种基金the Fundamental Research Funds for the Central Universities(HUST:2017KFYXJJ027)the National Basic Research Program of China(2015CB921102).
文摘Twisted trilayer graphene(TLG)may be the simplest realistic system so far,which has flat bands with nontrivial topology.Here,we give a comprehensive calculation about its band structures and the band topology,i.e.,valley Chern number of the nearly flat bands,with the continuum model.With realistic parameters,the magic angle of twisted TLG is about 1.12°,at which two nearly flat bands appears.Unlike the twisted bilayer graphene,a small twist angle can induce a tiny gap at all the Dirac points,which can be enlarged further by a perpendicular electric field.The valley Chern numbers of the two nearly flat bands in the twisted TLG depends on the twist angleθand the perpendicular electric field E⊥.Considering its topological flat bands,the twisted TLG should be an ideal experimental platform to study the strongly correlated physics in topologically nontrivial flat band systems.And,due to its reduced symmetry,the correlated states in twisted TLG should be quite different from that in twisted bilayer graphene and twisted double bilayer graphene.
基金supported by the National Natural Science Foundation of China(Grant No.10933002)
文摘During the evolution of the binary system, many physical processes occur, which can influence the orbital angular velocity and the spin angular velocities of the two components, and influence the non-synchronous or synchronous rotation of the system. These processes include the transfer of masses and angular momentums between the component stars, the loss of mass and angular momentum via stellar winds, and the deformation of the structure of component stars. A study of these processes indicates that they are closely related to the combined effects of tide and rotation. This means, to study the synchronous or non-synchronous rotation of binary systems, one has to consider the contributions of different physical processes simultaneously, instead of the tidal effect alone. A way to know whether the rotation of a binary system is synchronous or non-synchronous is to calculate the orbital angular velocity and the spin angular velocities of the component stars. If all of these angular velocities are equal, the rotation of the system is synchronous. If not, the rotation of the system is non-synchronous. For this aim, a series of equations are developed to calculate the orbital and spin angular velocities. The evolutionary calculation of a binary system with masses of 10M~ ＋ 6Me shows that the transfer of masses and angular momentums between the two components, and the deformation of the components structure in the semidetached or in the contact phase can change the rotation of the system from synchronous into non-synchronous rotation.
