Effects of Rare Earth(Hereafter RE)on the conductance of high-purity and industrial-purity aluminum wires have been studied.RE increases the resistivity of the high-purity aluminum.No evidence has been found that RE w...Effects of Rare Earth(Hereafter RE)on the conductance of high-purity and industrial-purity aluminum wires have been studied.RE increases the resistivity of the high-purity aluminum.No evidence has been found that RE will decrease the resistivity of industrial-pure aluminum under various RE content including 0.3%Ce.The individual role of RE and its combined effects with Fe and Si have been discussed too.展开更多
It is important for the safety of transmission system to accurately calculate single-phase earth fault current distribution.Features of double sided elimination method were illustrated.Quantitative calculation of sing...It is important for the safety of transmission system to accurately calculate single-phase earth fault current distribution.Features of double sided elimination method were illustrated.Quantitative calculation of single-phase earth fault current distribution and case verification were accomplished by using the loop method.Influences of some factors,such as single-phase earth fault location and ground resistance of poles,on short-circuit current distribution were discussed.Results show that:1) results of the loop method conform to those of double sided elimination method;2) the fault location hardly influences macro-distribution of short-circuit current.However,current near fault location is evidently influenced;and 3) the short-circuit current distribution is not so sensitive to the ground resistance of poles.展开更多
Practically,the load currents in three phases are asymmetric in the power system.It means that the impedances are different in all three phases.If the consumer’s transformer neutral cut off and/or was disconnected fr...Practically,the load currents in three phases are asymmetric in the power system.It means that the impedances are different in all three phases.If the consumer’s transformer neutral cut off and/or was disconnected from the neutral of power supply source,then there will be some trouble and failure occurred.The current in the neutral wire drops down to zero when the neutral wire is cut off and the phase currents of all three-phase equal to each other since there was no return wire.The currents are equal but the voltages at the phase consumers are different.Especially for residential single-phase consumers,the voltage at the consumers of the phase varies differently for three phase systems when the neutral wire was disconnected at consumer side and even the voltage at the consumers one or two of those three phases becomes over nominal voltage or reaches nearly line voltage.In this case,the electronic appliances in that phase will be fed by high voltage than the rated value and they can be broken down.In the power system of UB(Ulaanbaatar)city,there are some occasional such kind of failures every year.Obviously,many electronic appliances were broken down due to high voltage and the electricity utility companies respond for service charge of damaged parts.展开更多
The effect of RE (such as Ce, Y and mixed Ce + Y, etc) on ageing precipitate, characteristics and softening resistance of Cu-Cr-Zr alloys contact wire used in electrical railway were investigated in this paper. The...The effect of RE (such as Ce, Y and mixed Ce + Y, etc) on ageing precipitate, characteristics and softening resistance of Cu-Cr-Zr alloys contact wire used in electrical railway were investigated in this paper. The results show that the tested Cu-Cr-Zr alloy with trace RE addition could attain higher microhardness and lower electrical conductivity to some extent after being soluted at 950 ℃ for 1 h and aged at 480 ℃. The precipitation process of secondary phase could be accelerated by cold working before ageing treatment which resulted in ageing hardening. Aged at 480 ℃ after 60% cold working, the values of electrical conductivity and microhardness improved significantly compared with that without deformation. The mixed RE (Ce + Y) improved the softening resistance substantially in these trace RE additions, which could increase the soften temperature by 45 ℃.展开更多
One kind of quenched Cr12 steel dies for impacting stainless steel wire rope (SSWR) was treated by low temperature liquid sulfurization catalyzed with rare earths, in order to extend their service life for assuring ...One kind of quenched Cr12 steel dies for impacting stainless steel wire rope (SSWR) was treated by low temperature liquid sulfurization catalyzed with rare earths, in order to extend their service life for assuring the continuity of production line, and simultaneously improve the surface quality of SSWR obtained. After immerged into the melting sulphur containing 4 % (mass fraction) of LaF3 and 1% of CeCl3 at 463 K for 4 h, the sulfurized dies were very smooth and black, with little distortion and hardness loss. They exhibited a certain extent of corrosion-resistance in air due to the coexisting rare earths in the sulfurized layer. Optical observations showed that the sulfurized layer was uniform and had scale-like structure. The trail of machined SSWR indicated that the production capacity of sulfurized dies had been doubled and the replacing period on line was postponed. SEM morphology also proved that the wear extent of cavities on sulfurized dies decreased greatly and the surface quality of SSWR obtained was improved markedly.展开更多
To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or ...To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or tension,span length,temperature change,elastic deformation,and the Earth’s rotation)of the vertical sag are summarized,and their validity is verified through actual measurements.Finally,the essential factors affecting vertical sag,i.e.,the specific strength and length,are discussed.It is believed that the vertical sag of a stretched wire is proportional to the square of the length and inversely proportional to the specific strength of the material.展开更多
The effects of the content of rare earth elements on the microstructure and properties of hot-dip Zn-5 Al alloy steel wire for bridge cables were investigated.The microstructure of the hot-dip coating was analyzed usi...The effects of the content of rare earth elements on the microstructure and properties of hot-dip Zn-5 Al alloy steel wire for bridge cables were investigated.The microstructure of the hot-dip coating was analyzed using an optical microscope and a scanning electron microscope equipped with an energy-dispersive spectrometer.The bonding force between the hot-dip coating and steel wire was determined by the winding test.The corrosion resistance of the steel wire hot-dip coating was tested by the electrochemical workstation.The hot-dip Zn-5A1 alloy coating has a corrosion-resistant structure composed of a zinc-rich phase and an aluminum-rich phase.Due to the enhanced bonding force,the micro structure of the hot-dip coating of the Zn-5A1 alloy with rare earth elements is more compact and uniform than that without rare earth elements.The addition of rare earth elements improves the corrosion resistance of Zn-5A1 alloy coated steel wire.Due to the rare earth segregation,which prevents the corrosion of the grain boundary and enhances the anti-intergranular corrosion performance,steel wire exhibits the optimum corrosion resistance when the content of rare earth elements is 0.08 wt.%.展开更多
文摘Effects of Rare Earth(Hereafter RE)on the conductance of high-purity and industrial-purity aluminum wires have been studied.RE increases the resistivity of the high-purity aluminum.No evidence has been found that RE will decrease the resistivity of industrial-pure aluminum under various RE content including 0.3%Ce.The individual role of RE and its combined effects with Fe and Si have been discussed too.
文摘It is important for the safety of transmission system to accurately calculate single-phase earth fault current distribution.Features of double sided elimination method were illustrated.Quantitative calculation of single-phase earth fault current distribution and case verification were accomplished by using the loop method.Influences of some factors,such as single-phase earth fault location and ground resistance of poles,on short-circuit current distribution were discussed.Results show that:1) results of the loop method conform to those of double sided elimination method;2) the fault location hardly influences macro-distribution of short-circuit current.However,current near fault location is evidently influenced;and 3) the short-circuit current distribution is not so sensitive to the ground resistance of poles.
文摘Practically,the load currents in three phases are asymmetric in the power system.It means that the impedances are different in all three phases.If the consumer’s transformer neutral cut off and/or was disconnected from the neutral of power supply source,then there will be some trouble and failure occurred.The current in the neutral wire drops down to zero when the neutral wire is cut off and the phase currents of all three-phase equal to each other since there was no return wire.The currents are equal but the voltages at the phase consumers are different.Especially for residential single-phase consumers,the voltage at the consumers of the phase varies differently for three phase systems when the neutral wire was disconnected at consumer side and even the voltage at the consumers one or two of those three phases becomes over nominal voltage or reaches nearly line voltage.In this case,the electronic appliances in that phase will be fed by high voltage than the rated value and they can be broken down.In the power system of UB(Ulaanbaatar)city,there are some occasional such kind of failures every year.Obviously,many electronic appliances were broken down due to high voltage and the electricity utility companies respond for service charge of damaged parts.
文摘The effect of RE (such as Ce, Y and mixed Ce + Y, etc) on ageing precipitate, characteristics and softening resistance of Cu-Cr-Zr alloys contact wire used in electrical railway were investigated in this paper. The results show that the tested Cu-Cr-Zr alloy with trace RE addition could attain higher microhardness and lower electrical conductivity to some extent after being soluted at 950 ℃ for 1 h and aged at 480 ℃. The precipitation process of secondary phase could be accelerated by cold working before ageing treatment which resulted in ageing hardening. Aged at 480 ℃ after 60% cold working, the values of electrical conductivity and microhardness improved significantly compared with that without deformation. The mixed RE (Ce + Y) improved the softening resistance substantially in these trace RE additions, which could increase the soften temperature by 45 ℃.
基金Project supported by the Natural Science Fund of Jiangsu Province (BK2002062)Startup Fund of Hohai University(2084/40501107)
文摘One kind of quenched Cr12 steel dies for impacting stainless steel wire rope (SSWR) was treated by low temperature liquid sulfurization catalyzed with rare earths, in order to extend their service life for assuring the continuity of production line, and simultaneously improve the surface quality of SSWR obtained. After immerged into the melting sulphur containing 4 % (mass fraction) of LaF3 and 1% of CeCl3 at 463 K for 4 h, the sulfurized dies were very smooth and black, with little distortion and hardness loss. They exhibited a certain extent of corrosion-resistance in air due to the coexisting rare earths in the sulfurized layer. Optical observations showed that the sulfurized layer was uniform and had scale-like structure. The trail of machined SSWR indicated that the production capacity of sulfurized dies had been doubled and the replacing period on line was postponed. SEM morphology also proved that the wear extent of cavities on sulfurized dies decreased greatly and the surface quality of SSWR obtained was improved markedly.
基金Large Research Infrastructures“China initiative Accelerator Driven System”(No.2017-000052-75-01-000590).
文摘To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or tension,span length,temperature change,elastic deformation,and the Earth’s rotation)of the vertical sag are summarized,and their validity is verified through actual measurements.Finally,the essential factors affecting vertical sag,i.e.,the specific strength and length,are discussed.It is believed that the vertical sag of a stretched wire is proportional to the square of the length and inversely proportional to the specific strength of the material.
基金The authors would like to acknowledge the support from Key-Area Research and Development Program of Guangdong Province(2019B111106002)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(21KJB460023).
文摘The effects of the content of rare earth elements on the microstructure and properties of hot-dip Zn-5 Al alloy steel wire for bridge cables were investigated.The microstructure of the hot-dip coating was analyzed using an optical microscope and a scanning electron microscope equipped with an energy-dispersive spectrometer.The bonding force between the hot-dip coating and steel wire was determined by the winding test.The corrosion resistance of the steel wire hot-dip coating was tested by the electrochemical workstation.The hot-dip Zn-5A1 alloy coating has a corrosion-resistant structure composed of a zinc-rich phase and an aluminum-rich phase.Due to the enhanced bonding force,the micro structure of the hot-dip coating of the Zn-5A1 alloy with rare earth elements is more compact and uniform than that without rare earth elements.The addition of rare earth elements improves the corrosion resistance of Zn-5A1 alloy coated steel wire.Due to the rare earth segregation,which prevents the corrosion of the grain boundary and enhances the anti-intergranular corrosion performance,steel wire exhibits the optimum corrosion resistance when the content of rare earth elements is 0.08 wt.%.