Mitigative effect of La on Glycine max seedlings under combined Pb and Cd pollution was studied through pot culture experiment. The results show that the growth and metabolism of Glycine max seedlings are inhibited by...Mitigative effect of La on Glycine max seedlings under combined Pb and Cd pollution was studied through pot culture experiment. The results show that the growth and metabolism of Glycine max seedlings are inhibited by the solution with 500 mg.L-1 Pb + 100 mg.L-1 Cd. When 30 mg. L-1 LaCl3 is used to spray Glycine max seedlings once, the injury effect of combined Pb and Cd pollution is reduced. The experiment proves that the effect is related to La which can raise photosynthetic rate, chlorophyll content and activity of nitrate reductase, and reduce cell membrane permeability, content of Pb and Cd, and keep TTC reduction ability of Glycine max seedling.展开更多
Ag BaO thin films doped with lanthanum were prepared by vacuum deposition. Compared with the normal Ag BaO thin film, there is almost no change with the shape and the peak site of the fluorescence spectrum; however,...Ag BaO thin films doped with lanthanum were prepared by vacuum deposition. Compared with the normal Ag BaO thin film, there is almost no change with the shape and the peak site of the fluorescence spectrum; however, fluorescence emission strength of the whole observation band(325～600 nm)increases about 40%, and the increase of short wavelength range is more remarkable than that of long wavelength range, which we named “blue stronger” phenomenon. Analytic results show that, with the forming of intermetallic compounds between silver and lanthanum, the 4f state energy levels lie just below the Fermi level within 5 eV. It is the energy exchange between the 4f energy levels and the conduction band that causes the increase effect of fluorescence emission, and it is the optical absorption cross section of 4f electron, which increases with the increase of energy of incidence photon, that gives rise to the “blue stronger” phenomenon.展开更多
The influence of lanthanum on the microstructure, deformed behavior, microcrack susceptibility of intermetallic compound Al 66 Mn 9Ti 25 was investigated. Adding lanthanum into intermetallic compound Al 6...The influence of lanthanum on the microstructure, deformed behavior, microcrack susceptibility of intermetallic compound Al 66 Mn 9Ti 25 was investigated. Adding lanthanum into intermetallic compound Al 66 Mn 9Ti 25 , the lattice parameters are not changed and the Ll 2 structure is maintained. At the same time, the dendritical grain and fine second phase are obtained, which inhibits the microcrack initiation and intergranular failure. On the other hand, the movability of dislocation is enhanced and the compressive ductility is improved. The mechanism about the role of lanthanum in intermetallic compound Al 66 Mn 9Ti 25 was discussed.展开更多
By means of adding low content of rare earth element La into Sn60 Pb40 solder alloy, the growth of Cu 6Sn 5 intermetallic compound at the interface of solder joint is hindered, and the thermal fatigue life of solde...By means of adding low content of rare earth element La into Sn60 Pb40 solder alloy, the growth of Cu 6Sn 5 intermetallic compound at the interface of solder joint is hindered, and the thermal fatigue life of solder joint is increased by 2 times. The results of thermodynamic calculation based on diffusion kinetics show that, the driving force for Cu 6Sn 5 growth is lowered by adding small content of La in Sn60 Pb40 solder alloy. Meanwhile, there is an effective local mole fraction range of La, in which, 0 18% is the limited value and 0 08% is the best value.展开更多
A composite of 60% of lanthanum stearate and 40%（mass fraction） of stearic acid was prepared and its influence on the crystallization characteristics of isotatic polypropylene （iPP） was investigated. The results s...A composite of 60% of lanthanum stearate and 40%（mass fraction） of stearic acid was prepared and its influence on the crystallization characteristics of isotatic polypropylene （iPP） was investigated. The results showed that we had found a new kind of β-crystalline form nucleating agent. The composite might induced rather high proportion of β-modification. The relative content of β-phase estimated by WAXD and DSC was 30% and 51.8% in a PP containing 2.5%（mass fraction） of the composite respectively. The isothermal crystallization at 130 ℃ and melting behavior examined by DSC revealed that the composite accelerated the overall rate of crystallization remarkably. The half crystallization period t1/2 decreased from 11 8 min of pure PP to 7 5 min of PP containing 2.5% of the composite. However, the composite had no obvious influence on crystallization mode and the size of α-crystal unit cell.展开更多
文摘Mitigative effect of La on Glycine max seedlings under combined Pb and Cd pollution was studied through pot culture experiment. The results show that the growth and metabolism of Glycine max seedlings are inhibited by the solution with 500 mg.L-1 Pb + 100 mg.L-1 Cd. When 30 mg. L-1 LaCl3 is used to spray Glycine max seedlings once, the injury effect of combined Pb and Cd pollution is reduced. The experiment proves that the effect is related to La which can raise photosynthetic rate, chlorophyll content and activity of nitrate reductase, and reduce cell membrane permeability, content of Pb and Cd, and keep TTC reduction ability of Glycine max seedling.
文摘Ag BaO thin films doped with lanthanum were prepared by vacuum deposition. Compared with the normal Ag BaO thin film, there is almost no change with the shape and the peak site of the fluorescence spectrum; however, fluorescence emission strength of the whole observation band(325～600 nm)increases about 40%, and the increase of short wavelength range is more remarkable than that of long wavelength range, which we named “blue stronger” phenomenon. Analytic results show that, with the forming of intermetallic compounds between silver and lanthanum, the 4f state energy levels lie just below the Fermi level within 5 eV. It is the energy exchange between the 4f energy levels and the conduction band that causes the increase effect of fluorescence emission, and it is the optical absorption cross section of 4f electron, which increases with the increase of energy of incidence photon, that gives rise to the “blue stronger” phenomenon.
文摘The influence of lanthanum on the microstructure, deformed behavior, microcrack susceptibility of intermetallic compound Al 66 Mn 9Ti 25 was investigated. Adding lanthanum into intermetallic compound Al 66 Mn 9Ti 25 , the lattice parameters are not changed and the Ll 2 structure is maintained. At the same time, the dendritical grain and fine second phase are obtained, which inhibits the microcrack initiation and intergranular failure. On the other hand, the movability of dislocation is enhanced and the compressive ductility is improved. The mechanism about the role of lanthanum in intermetallic compound Al 66 Mn 9Ti 25 was discussed.
文摘By means of adding low content of rare earth element La into Sn60 Pb40 solder alloy, the growth of Cu 6Sn 5 intermetallic compound at the interface of solder joint is hindered, and the thermal fatigue life of solder joint is increased by 2 times. The results of thermodynamic calculation based on diffusion kinetics show that, the driving force for Cu 6Sn 5 growth is lowered by adding small content of La in Sn60 Pb40 solder alloy. Meanwhile, there is an effective local mole fraction range of La, in which, 0 18% is the limited value and 0 08% is the best value.
文摘A composite of 60% of lanthanum stearate and 40%（mass fraction） of stearic acid was prepared and its influence on the crystallization characteristics of isotatic polypropylene （iPP） was investigated. The results showed that we had found a new kind of β-crystalline form nucleating agent. The composite might induced rather high proportion of β-modification. The relative content of β-phase estimated by WAXD and DSC was 30% and 51.8% in a PP containing 2.5%（mass fraction） of the composite respectively. The isothermal crystallization at 130 ℃ and melting behavior examined by DSC revealed that the composite accelerated the overall rate of crystallization remarkably. The half crystallization period t1/2 decreased from 11 8 min of pure PP to 7 5 min of PP containing 2.5% of the composite. However, the composite had no obvious influence on crystallization mode and the size of α-crystal unit cell.
