A quench-treatment technique is used to prepare a high-quality polycrystalline sample of double perovskite Sr2FeMo06 （SFMO）. X-ray powder diffraction analysis reveals that the sample has a single phase and exhibits ...A quench-treatment technique is used to prepare a high-quality polycrystalline sample of double perovskite Sr2FeMo06 （SFMO）. X-ray powder diffraction analysis reveals that the sample has a single phase and exhibits I4/m symmetry. The cation order η of the sample increases to 98.9（2）% from 94.2（3）%, which is prepared by the traditional sol-gel method. The initial magnetization isotherm of the sample is detected at 300 K. Unit-cell magnetization for the current sample is 1.332 #s at 300 K, and the one for the traditional sol-gel method sample is 0.946#9. Unit-cell magnetization is enhanced to 40.80% by the quench-treatment technique. Quench treatment is an effective method of enhancing the Fe/Mo order and magnetic properties of double perovskite SFMO.展开更多
Mg-Y-Zn alloys with long period stacking ordered(LPSO)structure have received much attention recently and exhibit great potential in applications such as automotive,aerospace and in bio-medical fields.This paper aimed...Mg-Y-Zn alloys with long period stacking ordered(LPSO)structure have received much attention recently and exhibit great potential in applications such as automotive,aerospace and in bio-medical fields.This paper aimed to investigate the effect of different phase constitution of LPSO structures on corrosion rate of bio-medical Mg-Y-Zn alloys.The results showed that as-cast Mg98.5Y1Zn0.5 alloys containing only 18R structure exhibited the highest corrosion resistance with the corrosion rate of 2.78 mm/year.The precipitation of 14H lamellas within a-Mg grains during solid solution treatment introduced the crystallographic orientation corrosion by accelerating micro-galvanic corrosion.The increase of 18R/14H interfaces deteriorated the corrosion resistance,and the grain boundaries also suffered from severe electrochemical dissolution.This work suggested that Mg-Y-Zn alloys with single LPSO structure(either 18R or 14H)exhibited better corrosion resistance than alloys with co-existence 18R and I4H LPSO structures.展开更多
Industrialization is a major strategy of Vietnam for the development of the countryside. One such program is the promotion of craft villages that have been successful in increasing income levels that are 5 times more ...Industrialization is a major strategy of Vietnam for the development of the countryside. One such program is the promotion of craft villages that have been successful in increasing income levels that are 5 times more than those villages mainly engaged in agricultural production. However, while such programs have brought prosperity to these villages, they have ignored the adverse effects on the environment brought about by the wastewaters from the processing plants. Would these households involved in agro-food processing be willing to pay for the establishment of a wastewater plant to address the environmental problems? What factors would influence their willingness to pay? The results of the study among the selected households in Nhue-Day River Basin, Vietnam involved in agro-processing showed that the major factors affecting their willingness to pay for the establishment of a wastewater treatment plant are their level of education, quantity of households’ untreated wastewater, presence of young children who are more vulnerable to the adverse effects of pollution, experience of family members getting sick, households’ awareness of benefits from treated wastewater, capacity to pay, access to credit and membership in craft village’s Association. The study recommended that decisions on addressing environmental issues should be participatory to be able to take into consideration the socio-economic conditions of the stakeholders.展开更多
The microstructures and properties of Cu-8.0Ni-1.8Si alloy subjected to different heat treatments were examined by mechanical and electrical properties measurements,optical and transmission electron microscopes observ...The microstructures and properties of Cu-8.0Ni-1.8Si alloy subjected to different heat treatments were examined by mechanical and electrical properties measurements,optical and transmission electron microscopes observation. The results show that the precipitation process during aging can be accelerated by the cold deforming before aging. As the Cu-8.0Ni-1.8Si alloy is subjected to solution treatment at 970 ℃ for 4 h,cold rolling to 60% reduction,and then aging at 450 ℃ for 60 min,its properties are σb=1 050 MPa,σ0.2=786 MPa,δ=3.2% and conductivity 27.9%(IACS). The strengthening mechanisms of the alloy include spinodal decomposition strengthening,ordering strengthening and precipitation strengthening. The precipitation of the alloy is nano-scale Ni2Si phase.展开更多
Characterizations of phases in Mg-10%Y-5%Gd-2%Zn-0.5%Zr(WGZ1052) alloy during heat treatments were investigated by OM,XRD,SEM and EDS.The mechanisms of microstructure evolution were discussed.The results show that,aft...Characterizations of phases in Mg-10%Y-5%Gd-2%Zn-0.5%Zr(WGZ1052) alloy during heat treatments were investigated by OM,XRD,SEM and EDS.The mechanisms of microstructure evolution were discussed.The results show that,after high temperature heat treatments,the Mg12ZnY phases still exist.During solution-treatment at 535 °C,the amount of the long-period stacking order structures decreases.At 545 °C for 20 h and 24 h,there are still remnant Mg12ZnY compounds in the Mg matrix,the shape of which does not change and the amount does not decrease obviously.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No U1304110the Doctoral Science Foundation of Henan Normal University under Grant No 01026500109
文摘A quench-treatment technique is used to prepare a high-quality polycrystalline sample of double perovskite Sr2FeMo06 （SFMO）. X-ray powder diffraction analysis reveals that the sample has a single phase and exhibits I4/m symmetry. The cation order η of the sample increases to 98.9（2）% from 94.2（3）%, which is prepared by the traditional sol-gel method. The initial magnetization isotherm of the sample is detected at 300 K. Unit-cell magnetization for the current sample is 1.332 #s at 300 K, and the one for the traditional sol-gel method sample is 0.946#9. Unit-cell magnetization is enhanced to 40.80% by the quench-treatment technique. Quench treatment is an effective method of enhancing the Fe/Mo order and magnetic properties of double perovskite SFMO.
基金the National Natural Science Foundation of China(Grant Nos.51774109 and 51979099)the Fundamental Research Funds for the Central Universities(Grant No.2018B48414 and 2018B690X14)+3 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX18_0570)The Key Research and Development Project of Jiangsu Province of China(Grant No.BE2017148)Postgraduate Education Reform Project of Jiangsu Province(JGLX19_027)Natural Science Foundation of China(Grant No.51979099).
文摘Mg-Y-Zn alloys with long period stacking ordered(LPSO)structure have received much attention recently and exhibit great potential in applications such as automotive,aerospace and in bio-medical fields.This paper aimed to investigate the effect of different phase constitution of LPSO structures on corrosion rate of bio-medical Mg-Y-Zn alloys.The results showed that as-cast Mg98.5Y1Zn0.5 alloys containing only 18R structure exhibited the highest corrosion resistance with the corrosion rate of 2.78 mm/year.The precipitation of 14H lamellas within a-Mg grains during solid solution treatment introduced the crystallographic orientation corrosion by accelerating micro-galvanic corrosion.The increase of 18R/14H interfaces deteriorated the corrosion resistance,and the grain boundaries also suffered from severe electrochemical dissolution.This work suggested that Mg-Y-Zn alloys with single LPSO structure(either 18R or 14H)exhibited better corrosion resistance than alloys with co-existence 18R and I4H LPSO structures.
文摘Industrialization is a major strategy of Vietnam for the development of the countryside. One such program is the promotion of craft villages that have been successful in increasing income levels that are 5 times more than those villages mainly engaged in agricultural production. However, while such programs have brought prosperity to these villages, they have ignored the adverse effects on the environment brought about by the wastewaters from the processing plants. Would these households involved in agro-food processing be willing to pay for the establishment of a wastewater plant to address the environmental problems? What factors would influence their willingness to pay? The results of the study among the selected households in Nhue-Day River Basin, Vietnam involved in agro-processing showed that the major factors affecting their willingness to pay for the establishment of a wastewater treatment plant are their level of education, quantity of households’ untreated wastewater, presence of young children who are more vulnerable to the adverse effects of pollution, experience of family members getting sick, households’ awareness of benefits from treated wastewater, capacity to pay, access to credit and membership in craft village’s Association. The study recommended that decisions on addressing environmental issues should be participatory to be able to take into consideration the socio-economic conditions of the stakeholders.
基金Project(20040533069) supported by Doctoral Fund of the Ministry of Education, China
文摘The microstructures and properties of Cu-8.0Ni-1.8Si alloy subjected to different heat treatments were examined by mechanical and electrical properties measurements,optical and transmission electron microscopes observation. The results show that the precipitation process during aging can be accelerated by the cold deforming before aging. As the Cu-8.0Ni-1.8Si alloy is subjected to solution treatment at 970 ℃ for 4 h,cold rolling to 60% reduction,and then aging at 450 ℃ for 60 min,its properties are σb=1 050 MPa,σ0.2=786 MPa,δ=3.2% and conductivity 27.9%(IACS). The strengthening mechanisms of the alloy include spinodal decomposition strengthening,ordering strengthening and precipitation strengthening. The precipitation of the alloy is nano-scale Ni2Si phase.
基金Project(2009AA033501) supported by the National High-tech Research and Development Program of ChinaProject(2006BAE04B01-2) supported by the National Key Technology R&D Program of China Project(51074106) supported by the National Natural Science Foundation of China
文摘Characterizations of phases in Mg-10%Y-5%Gd-2%Zn-0.5%Zr(WGZ1052) alloy during heat treatments were investigated by OM,XRD,SEM and EDS.The mechanisms of microstructure evolution were discussed.The results show that,after high temperature heat treatments,the Mg12ZnY phases still exist.During solution-treatment at 535 °C,the amount of the long-period stacking order structures decreases.At 545 °C for 20 h and 24 h,there are still remnant Mg12ZnY compounds in the Mg matrix,the shape of which does not change and the amount does not decrease obviously.
