The variation of bonding ratio in the press bonding of TC4 alloy at temperatures from 850 to 900℃,pressures from 10 to 30 MPa,and time from 5 to 15 min was investigated.The bonding ratio increases with the increase o...The variation of bonding ratio in the press bonding of TC4 alloy at temperatures from 850 to 900℃,pressures from 10 to 30 MPa,and time from 5 to 15 min was investigated.The bonding ratio increases with the increase of temperature,time and pressure.The maximum bonding ratio,i.e.98 %,can be obtained at 900℃,30 MPa and 15 min.The significance and interaction of bonding parameters with the bonding ratio were investigated.The results demonstrate that the effect of pressure on the bonding ratio is the most effective and the effect of temperature is secondary,while the effect of time is not very powerful.The interaction of bonding parameter on the bonding ratio exists but that is distinguishing in different bonding parameter ranges.It is concluded that increasing pressure can be considered as the primary method to increase the bonding ratio.展开更多
A density functional theory （DFT） study has been carried out for [Zn-1AI（OH2）n＋6（OH）2n-2]^3＋ （n=3-6） and [Znn-1AI（OH2）2n-2（OH）2n-2]^3＋ （n = 7） clusters, which include the basic structural information ...A density functional theory （DFT） study has been carried out for [Zn-1AI（OH2）n＋6（OH）2n-2]^3＋ （n=3-6） and [Znn-1AI（OH2）2n-2（OH）2n-2]^3＋ （n = 7） clusters, which include the basic structural information of the brucite-like lattice structure of Zn/Al layered double hydroxides （LDHs） with Zn/AI molar ratio （R） in the range 2-6, in order to understand the effect of the Zn/Al ratio on the structure and stability of binary Zn/Al LDHs. Based on systematic calculations of the geometric parameters and formation energies of the cluster models, it was found that it is possible for Zn^2＋ and Al^3＋ cations to replace Mg^2＋ isomorphously in the brucite-like structure with different R values, resulting in differences in microstructure of the clusters and unit cell parameter a of the Zn/Al LDHs. Analysis of the geometry and bonding around the trivalent Al^3＋ or divalent Zn^2＋ cations reveals that Al^3＋ plays a more significant role than Zn^2＋ in determining the microstructure properties, formation and bonding stability of the corresponding ZnRAl clusters when R〈5, while the influence of Zn^2＋ becomes the dominant factor in the case of R〉 5. These findings are in good agreement with experiments. This work provides a detailed electronic-level understanding of how the composition of cations affects the microstructure and stability of Zn-containing binary LDH layers.展开更多
Factors influencing bonding strength of laminated bamboo strips lumber (LBSL) were investigated in this paper. In order to find an optimized technology, this paper investigated how the thickness of bamboo strips, the ...Factors influencing bonding strength of laminated bamboo strips lumber (LBSL) were investigated in this paper. In order to find an optimized technology, this paper investigated how the thickness of bamboo strips, the assembly orientation of bamboo curtain, the type of adhesives, as well as coupling agent treatment of bamboo curtain affected the bonding strength. The following conclusions were drawn: 1)The thinner the thickness of the bamboo strips, the bigger the bonding strength of LBSL; 2) The assembly orientation of the bamboo curtain benefited the bonding strength, MOR and MOE; 3) The bonding strength increased with the use of phenol-resorcinol-formaldehyde (PRF) resin; and 4) Treatment of coupling agent could increase the bonding strength but decrease both MOR and MOE.展开更多
基金financially supported by the National Natural Science Foundation of China (No.51275416)
文摘The variation of bonding ratio in the press bonding of TC4 alloy at temperatures from 850 to 900℃,pressures from 10 to 30 MPa,and time from 5 to 15 min was investigated.The bonding ratio increases with the increase of temperature,time and pressure.The maximum bonding ratio,i.e.98 %,can be obtained at 900℃,30 MPa and 15 min.The significance and interaction of bonding parameters with the bonding ratio were investigated.The results demonstrate that the effect of pressure on the bonding ratio is the most effective and the effect of temperature is secondary,while the effect of time is not very powerful.The interaction of bonding parameter on the bonding ratio exists but that is distinguishing in different bonding parameter ranges.It is concluded that increasing pressure can be considered as the primary method to increase the bonding ratio.
基金supported by the National Natural Science Foundation of China and the Program for Changjiang Scholars and Innovative Research Teams in Universities (Grant No.IRT0406)
文摘A density functional theory （DFT） study has been carried out for [Zn-1AI（OH2）n＋6（OH）2n-2]^3＋ （n=3-6） and [Znn-1AI（OH2）2n-2（OH）2n-2]^3＋ （n = 7） clusters, which include the basic structural information of the brucite-like lattice structure of Zn/Al layered double hydroxides （LDHs） with Zn/AI molar ratio （R） in the range 2-6, in order to understand the effect of the Zn/Al ratio on the structure and stability of binary Zn/Al LDHs. Based on systematic calculations of the geometric parameters and formation energies of the cluster models, it was found that it is possible for Zn^2＋ and Al^3＋ cations to replace Mg^2＋ isomorphously in the brucite-like structure with different R values, resulting in differences in microstructure of the clusters and unit cell parameter a of the Zn/Al LDHs. Analysis of the geometry and bonding around the trivalent Al^3＋ or divalent Zn^2＋ cations reveals that Al^3＋ plays a more significant role than Zn^2＋ in determining the microstructure properties, formation and bonding stability of the corresponding ZnRAl clusters when R〈5, while the influence of Zn^2＋ becomes the dominant factor in the case of R〉 5. These findings are in good agreement with experiments. This work provides a detailed electronic-level understanding of how the composition of cations affects the microstructure and stability of Zn-containing binary LDH layers.
基金supported by the national Key Project of Scientific and Technical Supporting Programs of China (No.2006BAD19B0503)
文摘Factors influencing bonding strength of laminated bamboo strips lumber (LBSL) were investigated in this paper. In order to find an optimized technology, this paper investigated how the thickness of bamboo strips, the assembly orientation of bamboo curtain, the type of adhesives, as well as coupling agent treatment of bamboo curtain affected the bonding strength. The following conclusions were drawn: 1)The thinner the thickness of the bamboo strips, the bigger the bonding strength of LBSL; 2) The assembly orientation of the bamboo curtain benefited the bonding strength, MOR and MOE; 3) The bonding strength increased with the use of phenol-resorcinol-formaldehyde (PRF) resin; and 4) Treatment of coupling agent could increase the bonding strength but decrease both MOR and MOE.
