Polyphenylene sulfone/graphene oxide(PPSU/GO) mixed matrix membranes with different GO contents are prepared by phase inversion technique using, PEG-1000 as porogen, and N,N-dimethylacetamide(DMAC) as solvent.The hydr...Polyphenylene sulfone/graphene oxide(PPSU/GO) mixed matrix membranes with different GO contents are prepared by phase inversion technique using, PEG-1000 as porogen, and N,N-dimethylacetamide(DMAC) as solvent.The hydrophilicity and pure water flux of the membrane are investigated. The morphology, hydrophilicity, thermodynamic stability and compatibility of the membranes are characterized by various techniques such as SEM,TGA, FTIR and so on. The permeation properties of the membrane are measured in terms of pure water flux and bovine serum albumin(BSA) retention. The results indicate that when the GO content is 1.5 wt%, an evenly distributed finger structure has been formed in the mixed matrix membranes. Owing to the presence of GO,the hydrophilicity and the thermal stability of the membranes are improved, and the fouling resistance is also enhanced.展开更多
The effects of Li~+ co-doping concentration on the structure, upconversion luminescence and temperature sensing behavior of Er^(3+):La_2O_3 phosphors were investigated. X-ray diffraction and scanning electron mic...The effects of Li~+ co-doping concentration on the structure, upconversion luminescence and temperature sensing behavior of Er^(3+):La_2O_3 phosphors were investigated. X-ray diffraction and scanning electron microscopy observations reveal that Li~+ ion co-doping can change the lattice parameter of La_2O_3 host and increase the particle size of the samples. The optical investigation shows that co-doping of Li~+ ions can enhance the upconversion emission of Er^(3+) ions in La_2O_3 matrix effectively. Most importantly, the temperature sensing sensitivity of the samples is found to be dependent on Li~+ co-doping concentration,when the emission intensity ratio of the(~2H_(11/2)→~4 I_(15/2)) and(~4 S_(3/2)→~4 I_(15/2)) transitions of Er^(3+) is chosen as the thermometric index. Both of the optimum upconversion luminescence and temperature sensing sensitivity are obtained for 7 mol% Li~+ co-doped sample. When the Li~+ concentration is beyond 7 mol%,both the quenching in upconversion intensity and the degradation of temperature sensitivity are observed, which may be due to the serious distortion in local crystal field around Er^(3+) ions caused by the excess Li~+ ions.展开更多
By Using (scanning) transmission electron microscopy, localized-corrosion morphology variations of the AA7055 AIZn(Cu)Mg alloy with different thermal processes and their underlying microscopic causes were investig...By Using (scanning) transmission electron microscopy, localized-corrosion morphology variations of the AA7055 AIZn(Cu)Mg alloy with different thermal processes and their underlying microscopic causes were investigated systematically. Our study shows that the corrosion resistance of the nanoscale precipitates varies with their structure type and Cu-content. Just like the Al-matrix, the early-stage precipitates are corrosion resistant, as compared with the ηp/η-precipitates without high Cu-content. With a high Cu-content, however, the η-precipitates become most corrosion resistant among all phases involved. Hence, tailoring the precipitate microstructure and chemistry though thermal processes may change the overall corrosion morphology and improve corrosion resistance property of the alloy.展开更多
To obtain a good combination of strength and ductility, a laminated composite structure composed of recovered hard lamellae and soft recrystallized lamellae has been produced in a single phase austenitic Fe-34.5 Mn-0....To obtain a good combination of strength and ductility, a laminated composite structure composed of recovered hard lamellae and soft recrystallized lamellae has been produced in a single phase austenitic Fe-34.5 Mn-0.04C steel by cold rolling and partial recrystallization. Enhanced mechanical properties in both strength and ductility have been obtained in the composite structure compared to a fully recrystallized coarse grain structure. A further increase in strength with only minor loss in total elongation has been achieved by a slight cold rolling of the composite structure, which also removes the small yield drop and Luders elongation observed in the composite structure.展开更多
基金Supported by the Natural Science Foundation of Hebei Province(B2016209059)the Training Fund Project of North China University of Science and Technology(sp201520)
文摘Polyphenylene sulfone/graphene oxide(PPSU/GO) mixed matrix membranes with different GO contents are prepared by phase inversion technique using, PEG-1000 as porogen, and N,N-dimethylacetamide(DMAC) as solvent.The hydrophilicity and pure water flux of the membrane are investigated. The morphology, hydrophilicity, thermodynamic stability and compatibility of the membranes are characterized by various techniques such as SEM,TGA, FTIR and so on. The permeation properties of the membrane are measured in terms of pure water flux and bovine serum albumin(BSA) retention. The results indicate that when the GO content is 1.5 wt%, an evenly distributed finger structure has been formed in the mixed matrix membranes. Owing to the presence of GO,the hydrophilicity and the thermal stability of the membranes are improved, and the fouling resistance is also enhanced.
基金Project supported by the National Natural Science Foundation of China(51401197,61605192)the Natural Science Foundation of Zhejiang Province(LQ13F050003,LZ14B010001)
文摘The effects of Li~+ co-doping concentration on the structure, upconversion luminescence and temperature sensing behavior of Er^(3+):La_2O_3 phosphors were investigated. X-ray diffraction and scanning electron microscopy observations reveal that Li~+ ion co-doping can change the lattice parameter of La_2O_3 host and increase the particle size of the samples. The optical investigation shows that co-doping of Li~+ ions can enhance the upconversion emission of Er^(3+) ions in La_2O_3 matrix effectively. Most importantly, the temperature sensing sensitivity of the samples is found to be dependent on Li~+ co-doping concentration,when the emission intensity ratio of the(~2H_(11/2)→~4 I_(15/2)) and(~4 S_(3/2)→~4 I_(15/2)) transitions of Er^(3+) is chosen as the thermometric index. Both of the optimum upconversion luminescence and temperature sensing sensitivity are obtained for 7 mol% Li~+ co-doped sample. When the Li~+ concentration is beyond 7 mol%,both the quenching in upconversion intensity and the degradation of temperature sensitivity are observed, which may be due to the serious distortion in local crystal field around Er^(3+) ions caused by the excess Li~+ ions.
基金financially supported by the National Natural Science Foundation of China(Nos.51501059,51471067,51501060,and 11427806)the National Key Research and Development Program of China(No.2016YFB0300801)
文摘By Using (scanning) transmission electron microscopy, localized-corrosion morphology variations of the AA7055 AIZn(Cu)Mg alloy with different thermal processes and their underlying microscopic causes were investigated systematically. Our study shows that the corrosion resistance of the nanoscale precipitates varies with their structure type and Cu-content. Just like the Al-matrix, the early-stage precipitates are corrosion resistant, as compared with the ηp/η-precipitates without high Cu-content. With a high Cu-content, however, the η-precipitates become most corrosion resistant among all phases involved. Hence, tailoring the precipitate microstructure and chemistry though thermal processes may change the overall corrosion morphology and improve corrosion resistance property of the alloy.
基金support from the National Natural Foundation of Hebei Province,China(Grant No.E2018203312)support of State Key Research and Development Program of MOST of China(2016YFB0700401)support of the 111 Project(B16007)by the Ministry of Education and the State Administration of Foreign Experts Affairs of China
文摘To obtain a good combination of strength and ductility, a laminated composite structure composed of recovered hard lamellae and soft recrystallized lamellae has been produced in a single phase austenitic Fe-34.5 Mn-0.04C steel by cold rolling and partial recrystallization. Enhanced mechanical properties in both strength and ductility have been obtained in the composite structure compared to a fully recrystallized coarse grain structure. A further increase in strength with only minor loss in total elongation has been achieved by a slight cold rolling of the composite structure, which also removes the small yield drop and Luders elongation observed in the composite structure.