Based on twin-roll casting, a cast-rolling force model was proposed to predict the rolling force in the bimetal solid-liquid cast-rolling bonding(SLCRB) process. The solid-liquid bonding zone was assumed to be below t...Based on twin-roll casting, a cast-rolling force model was proposed to predict the rolling force in the bimetal solid-liquid cast-rolling bonding(SLCRB) process. The solid-liquid bonding zone was assumed to be below the kiss point(KP). The deformation resistance of the liquid zone was ignored. Then, the calculation model was derived. A 2D thermal-flow coupled simulation was established to provide a basis for the parameters in the model, and then the rolling forces of the Cu/Al clad strip at different rolling speeds were calculated. Meanwhile, through measurement experiments, the accuracy of the model was verified. The influence of the rolling speed, the substrate strip thickness, and the material on the rolling force was obtained. The results indicate that the rolling force decreases with the increase of the rolling speed and increases with the increase of the thickness and thermal conductivity of the substrate strip. The rolling force is closely related to the KP height. Therefore, the formulation of reasonable process parameters to control the KP height is of great significance to the stability of cast-rolling forming.展开更多
The mechanical properties and product thickness specifications of bimetallic clad strip prepared by twin-roll casting are tightly related to the mechanical behavior of bonding interface interaction.The thermal−flow co...The mechanical properties and product thickness specifications of bimetallic clad strip prepared by twin-roll casting are tightly related to the mechanical behavior of bonding interface interaction.The thermal−flow coupled simulation and the interface pressure calculation models are established with the cast-rolling velocity as the variable.The results show that the interface temperature decreases,the interface pressure and the proportion of the thickness of the Al side increase with the decrease in cast-rolling velocity.The thinning of Cu strip mainly occurs in the backward slip zone.The higher pressure and longer solid/semi-solid contact time make the interface bonded fully,which provides favorable conditions for atomic diffusion.The inter-diffusion zone with a width of 4.9μm is attained at a cast-rolling velocity of 2.4 m/min,and the Cu side surface is nearly completely covered by aluminum.Therefore,the ductile fracture occurs on the Al side,which prevents the propagation of interface delamination cracks effectively.Meanwhile,shear effect becomes more significant at high interfacial pressure and large plastic strain,and the microstructure on Al side is composed of slender columnar crystals.Thus,the metallurgical bonding and refinement of grains on the Al side can result in higher bonding strength and tensile properties of the clad strip.展开更多
A series of new 3-benzoheterocyclic substituted pyridopyrimidines were designed and synthesized. Structures of the compounds were determined by IR, 1H NMR, and elemental analyses. The anti- proliferation activity of 1...A series of new 3-benzoheterocyclic substituted pyridopyrimidines were designed and synthesized. Structures of the compounds were determined by IR, 1H NMR, and elemental analyses. The anti- proliferation activity of 13 novel compounds was evaluated in A549, HL-60, BGC-823 and SMMC-7721 cell lines. Compounds 3, 5, 7, 8, 9,10 showed potent inhibitory activity against the four tested cancer cell lines. These six compounds were examined for Top I inhibition at 100 μmol/L by measuring the relaxation of supercoiled DNA in plasmid pBR322. Most of the tested compounds inhibited the enzyme at this concentration. The most potent compound 9 was as potent as camptothecin.展开更多
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(51974278)the Distinguished Young Fund of Natural Science Foundation of Hebei Province,China(E2018203446).
文摘Based on twin-roll casting, a cast-rolling force model was proposed to predict the rolling force in the bimetal solid-liquid cast-rolling bonding(SLCRB) process. The solid-liquid bonding zone was assumed to be below the kiss point(KP). The deformation resistance of the liquid zone was ignored. Then, the calculation model was derived. A 2D thermal-flow coupled simulation was established to provide a basis for the parameters in the model, and then the rolling forces of the Cu/Al clad strip at different rolling speeds were calculated. Meanwhile, through measurement experiments, the accuracy of the model was verified. The influence of the rolling speed, the substrate strip thickness, and the material on the rolling force was obtained. The results indicate that the rolling force decreases with the increase of the rolling speed and increases with the increase of the thickness and thermal conductivity of the substrate strip. The rolling force is closely related to the KP height. Therefore, the formulation of reasonable process parameters to control the KP height is of great significance to the stability of cast-rolling forming.
基金the financial support from the National Natural Science Foundation of China (No. 51974278)the Natural Science Foundation of Hebei Province Distinguished Young Fund Project, China (No. E2018203446)the National Foundation of Key Research and Development Project of China (No. 2018YFA0707303)
文摘The mechanical properties and product thickness specifications of bimetallic clad strip prepared by twin-roll casting are tightly related to the mechanical behavior of bonding interface interaction.The thermal−flow coupled simulation and the interface pressure calculation models are established with the cast-rolling velocity as the variable.The results show that the interface temperature decreases,the interface pressure and the proportion of the thickness of the Al side increase with the decrease in cast-rolling velocity.The thinning of Cu strip mainly occurs in the backward slip zone.The higher pressure and longer solid/semi-solid contact time make the interface bonded fully,which provides favorable conditions for atomic diffusion.The inter-diffusion zone with a width of 4.9μm is attained at a cast-rolling velocity of 2.4 m/min,and the Cu side surface is nearly completely covered by aluminum.Therefore,the ductile fracture occurs on the Al side,which prevents the propagation of interface delamination cracks effectively.Meanwhile,shear effect becomes more significant at high interfacial pressure and large plastic strain,and the microstructure on Al side is composed of slender columnar crystals.Thus,the metallurgical bonding and refinement of grains on the Al side can result in higher bonding strength and tensile properties of the clad strip.
基金supported by the National Natural Science Foundation of China(No.21072232)the Fundamental Research Funds for the Central Universities(No.JKZ2011002)+2 种基金the National Science&Technology Major Project(Nos.2012ZX09304-001 and 2013ZX09103-001-007)the Program for Changjiang Scholars and Innovative Research Team in University(No.PCSIRT-IRT1193)the‘‘Qinglan Project’’of Jiangsu Province
文摘A series of new 3-benzoheterocyclic substituted pyridopyrimidines were designed and synthesized. Structures of the compounds were determined by IR, 1H NMR, and elemental analyses. The anti- proliferation activity of 13 novel compounds was evaluated in A549, HL-60, BGC-823 and SMMC-7721 cell lines. Compounds 3, 5, 7, 8, 9,10 showed potent inhibitory activity against the four tested cancer cell lines. These six compounds were examined for Top I inhibition at 100 μmol/L by measuring the relaxation of supercoiled DNA in plasmid pBR322. Most of the tested compounds inhibited the enzyme at this concentration. The most potent compound 9 was as potent as camptothecin.
