Cu matrix composite reinforced with 10%（volume fraction） carbon nanotubes（CNTs/Cu） and pure Cu bulk were prepared by powder metallurgy techniques under the same consolidation processing condition.The effect of ele...Cu matrix composite reinforced with 10%（volume fraction） carbon nanotubes（CNTs/Cu） and pure Cu bulk were prepared by powder metallurgy techniques under the same consolidation processing condition.The effect of electrical current on tribological property of the materials was investigated by using a pin-on-disk friction and wear tester.The results show that the friction coefficient and wear rate of CNTs/Cu composite as well as those of pure Cu bulk increase with increasing the electrical current without exception,and the effect of electrical current is more obvious on tribological property of pure Cu bulk than on that of CNTs/Cu composite;the dominant wear mechanisms are arc erosion wear and plastic flow deformation,respectively;CNTs can improve tribological property of Cu matrix composites with electrical current.展开更多
R-phycoerythrin, a light-harvesting protein in some marine algae, and can be widely used in medicine, was isolated and purified from a red alga, Palmaria palmata (Lannaeus) Kuntze, using the streamline column (expande...R-phycoerythrin, a light-harvesting protein in some marine algae, and can be widely used in medicine, was isolated and purified from a red alga, Palmaria palmata (Lannaeus) Kuntze, using the streamline column (expanded bed adsorption) combined with ion-exchange chromatography. Because the crude extract was applied to the column upwardly, the column would not be blocked by polysaccharides usually very abundant in the extract of marine alga, this kind of blockage could hardly lie overcome in ordinary chromatographic column. After applying the crude extract containing 0.5 mol/L (NH4)(2)SO4, (NH4)(2)SO4 solution of different concentrations (0.2 mol/L, 0.1 mol/L and 0.05 mol/L) was used to elute the column downwardly and the eluates were collected and desalted. The desalted eluates were then applied onto all ion-exchange chromatographic column loaded with Q-sepharose for further purification of the R-phycoerythrin. Through these two steps, the purity (OD565/OD280) of the R-phycoerythrin from P. palmata was up to 3.5, more than 3.2, the commonly accepted criterion for purity, and the yield of the purified R-phycoerythrin could reach 0.122 mg/g of frozen P. palmata, much higher than that of phycobiliproteins purified with the previous methods. The result indicated that the cost of R-phycoerythrin will drop down with the method reported in this article.展开更多
[ Objective ] This study was to express and purify Arabidopsis thaliana heat shock factor HSF1. [ Method ] Using Escherichia coli M15 harboring HSF1 （pQE32/His6-HSF1, pREP4） as experimental materials, HSF1 was induc...[ Objective ] This study was to express and purify Arabidopsis thaliana heat shock factor HSF1. [ Method ] Using Escherichia coli M15 harboring HSF1 （pQE32/His6-HSF1, pREP4） as experimental materials, HSF1 was induced to express with isopropyl-β-D-galactoside （IPTG） ; then the expression product was purified using Ni-NTA-agarose affinity chromatography and analyzed by SDS-PAGE. [Result] HSF1 of Arabidopsis thaliana was successfully expressed and purified. [ Conclusion] This study provides materials for understanding the blinding site of HSF1 on Arabidopsis thaliana chromosome, further laying a good foundation for revealing the regulatory mechanism and physiological function of HSF1.展开更多
The composition and size distribution of cutting waste were characterized. The Si-rich powders were obtained from the cutting waste using a physical sedimentation process, and then further purified by removing impurit...The composition and size distribution of cutting waste were characterized. The Si-rich powders were obtained from the cutting waste using a physical sedimentation process, and then further purified by removing impurity using acid leaching. The effects of process parameters such as acid leaching time, temperature and the ratio of solid to liquid on the purification efficiency were investigated, and the parameters were optimized. Afterwards, the high-purity Si ingot was obtained by melting the Si-rich powders in vacuum furnace. Finally, the high purity Si with 99.96%Si, 1.1×10^-6 boron （B）, and 4.0×10^-6 phosphorus （P） were obtained. The results indicate that it is feasible to extract high-purity Si, and further produce SoG-Si from the cutting slurry waste.展开更多
The evolution of morphology, composition, thickness and corrosion resistance of the oxide film on pure Sn solder substrate submitted to high-temperature aging in 150 °C dry atmosphere was investigated. The result...The evolution of morphology, composition, thickness and corrosion resistance of the oxide film on pure Sn solder substrate submitted to high-temperature aging in 150 °C dry atmosphere was investigated. The results indicate that high-temperature aging accelerates the dehydration of Sn(OH)_(4)in the pre-existing native oxide film to form SnO_(2)and facilitates the oxidation of fresh Sn substrate, resulting in the gradual increase in oxide film thickness and surface roughness with prolonging aging time. However, the corrosion resistance of the film initially is enhanced and then deteriorated with an extending aging time. Besides, the formation and evolution mechanisms of the oxide film with aging time were discussed.展开更多
This paper considers the pure bending problem of simply supported transversely isotropic circular plates with elastic compliance coefficients being arbitrary functions of the thickness coordinate. First, the partial d...This paper considers the pure bending problem of simply supported transversely isotropic circular plates with elastic compliance coefficients being arbitrary functions of the thickness coordinate. First, the partial differential equation, which is satisfied by the stress functions for the axisymmetric deformation problem is derived. Then, stress functions are obtained by proper manipulation. The analytical expressions of axial force, bending moment and displacements are then deduced through integration. And then, stress functions are employed to solve problems of transversely isotropic functionally graded circular plate, with the integral constants completely determined from boundary conditions. An elasticity solution for pure bending problem, which coincides with the available solution when degenerated into the elasticity solutions for homogenous circular plate, is thus obtained. A numerical example is finally presented to show the effect of material inhomogeneity on the elastic field in a simply supported circular plate of transversely isotropic functionally graded material (FGM).展开更多
Objective： To study the effect of surface configuration and roughness on the corrosion resistance of pure Titanium （Ti） after used in oral environment for half a year. Methods ：Three edentulous volunteers with hea...Objective： To study the effect of surface configuration and roughness on the corrosion resistance of pure Titanium （Ti） after used in oral environment for half a year. Methods ：Three edentulous volunteers with healthy oral mucosa participated in an in vivo study. Four kinds of pure Ti testing pieces with different surface roughness were fixed in the polished surface of upper complete dentures and the other in the tissue surface of the dentures. After 6-month wearing the denture, dynamic polarization curves were traced with electrochemical method. Results：Ep and Ip of specimen used in oral cavity was higher than that left in air,which meant corrosion resistance falling. Compared to plane one ,Ecorr of wrinkly specimen was more positive,and Ep and Ip were more higher,so its corrosion resistance reduced. With the increase of surface roughness,Ep and Ip increased from 0.937 V and 1.810μA （Group Ⅱ） to 1.701 V and 2.252μA （Group Ⅳ）respectively,there was even no passivation in Group Ⅲ （which was the most coarse）,so proneness to corrosion enhanced. For specimen with the same surface roughness ,Ep and Ip of Group Ⅳ （1.701 V and 2.252 μA respectively） ,which was placed on polished surface of denture base,was higher than that on tissue surface（Group V , 1. 304 V, 1. 946μA）. Conclusion： From the perspective of corrosion behavior, wrinkly surface should not be adopted when pure Ti prosthesis is used,and surface roughness on the polishing surface of pure Ti prosthesis should be paid more attention,especially on clasps and connectors, where there is often more force to be exerted.展开更多
In the past ^68Ge （Germanium-68） was purified with toxic organic solvents in liquid-liquid extractions making the product unacceptable by the FDA （food and drug Administration） for human use. The authors report in...In the past ^68Ge （Germanium-68） was purified with toxic organic solvents in liquid-liquid extractions making the product unacceptable by the FDA （food and drug Administration） for human use. The authors report initial studies utilizing three or four columns consisting of sequences of AG 1, AG50, Chelex 100 and/or Sephadex G25 resins. Five purification methods were examined and a separation consisting of the sequence： AG 1-Chelex100-Sephedex G25 provided 87% recovery of germanium. Fractionation of the elution resulted in high germanium concentrations.展开更多
In the current study,an effort has been taken to manufacture and compare the characteristics of functionally graded tubes. Two samples have been produced with a commercially pure aluminium matrix reinforced by 10%(in ...In the current study,an effort has been taken to manufacture and compare the characteristics of functionally graded tubes. Two samples have been produced with a commercially pure aluminium matrix reinforced by 10%(in weight) SiC and Al_(2)O_(3)with a 16 μm average size via horizontal centrifugal casting. In addition to microstructure analysis,the mechanical and wear characteristics have been investigated across the thickness of the produced tubes.The results showed that the addition of SiC and Al_(2)O_(3)particles relative to the unreinforced matrix(pure Al)significantly enhance the mechanical properties and wear resistance of the produced tubes. Thus,these tubes are the best choice for automobile applications.展开更多
The dissimilar joining of CP-copper to 304 stainless steel was performed by gas tungsten arc welding process using different filler materials. The results indicated the formation of defect free joint by using copper f...The dissimilar joining of CP-copper to 304 stainless steel was performed by gas tungsten arc welding process using different filler materials. The results indicated the formation of defect free joint by using copper filler material. But, the presence of some defects like solidification crack and lack of fusion caused decreasing tensile strength of other joints. In the optimum conditions, the tensile strength of the joint was 96% of the weaker material. Also, this joint was bent till to 180° without any macroscopic defects like separation, tearing or fracture. It was concluded that copper is a new and good candidate for gas tungsten arc welding of copper to 304 stainless steel.展开更多
Chromaticity characteristics of several fluorescent dyes in cloth were studied in terms of chromaticity diagram. The dominant wavelength and color purity of the samples were calculated and chromaticity diagrams were d...Chromaticity characteristics of several fluorescent dyes in cloth were studied in terms of chromaticity diagram. The dominant wavelength and color purity of the samples were calculated and chromaticity diagrams were drawn to provide countermeasures with which the perceptual color attributes such as hue and saturation are correlated.展开更多
Using ultra high purity NaF-NaKCO3 in the Fluorescence spectrometry, determination of sub ppb levels of Uranium in the electronic materials has been achieved. The method could be applied to determination of Uranium in...Using ultra high purity NaF-NaKCO3 in the Fluorescence spectrometry, determination of sub ppb levels of Uranium in the electronic materials has been achieved. The method could be applied to determination of Uranium in any electronic materials.展开更多
基金Project(2007CB607603)supported by the National Basic Research Program of China
文摘Cu matrix composite reinforced with 10%（volume fraction） carbon nanotubes（CNTs/Cu） and pure Cu bulk were prepared by powder metallurgy techniques under the same consolidation processing condition.The effect of electrical current on tribological property of the materials was investigated by using a pin-on-disk friction and wear tester.The results show that the friction coefficient and wear rate of CNTs/Cu composite as well as those of pure Cu bulk increase with increasing the electrical current without exception,and the effect of electrical current is more obvious on tribological property of pure Cu bulk than on that of CNTs/Cu composite;the dominant wear mechanisms are arc erosion wear and plastic flow deformation,respectively;CNTs can improve tribological property of Cu matrix composites with electrical current.
文摘R-phycoerythrin, a light-harvesting protein in some marine algae, and can be widely used in medicine, was isolated and purified from a red alga, Palmaria palmata (Lannaeus) Kuntze, using the streamline column (expanded bed adsorption) combined with ion-exchange chromatography. Because the crude extract was applied to the column upwardly, the column would not be blocked by polysaccharides usually very abundant in the extract of marine alga, this kind of blockage could hardly lie overcome in ordinary chromatographic column. After applying the crude extract containing 0.5 mol/L (NH4)(2)SO4, (NH4)(2)SO4 solution of different concentrations (0.2 mol/L, 0.1 mol/L and 0.05 mol/L) was used to elute the column downwardly and the eluates were collected and desalted. The desalted eluates were then applied onto all ion-exchange chromatographic column loaded with Q-sepharose for further purification of the R-phycoerythrin. Through these two steps, the purity (OD565/OD280) of the R-phycoerythrin from P. palmata was up to 3.5, more than 3.2, the commonly accepted criterion for purity, and the yield of the purified R-phycoerythrin could reach 0.122 mg/g of frozen P. palmata, much higher than that of phycobiliproteins purified with the previous methods. The result indicated that the cost of R-phycoerythrin will drop down with the method reported in this article.
基金Supported by National Natural Science Foundation of China(30560012)Foundation of General Project of Yunnan Province(2007C261M)Foundation of Yunnan Educational Committee(07C10700)~~
文摘[ Objective ] This study was to express and purify Arabidopsis thaliana heat shock factor HSF1. [ Method ] Using Escherichia coli M15 harboring HSF1 （pQE32/His6-HSF1, pREP4） as experimental materials, HSF1 was induced to express with isopropyl-β-D-galactoside （IPTG） ; then the expression product was purified using Ni-NTA-agarose affinity chromatography and analyzed by SDS-PAGE. [Result] HSF1 of Arabidopsis thaliana was successfully expressed and purified. [ Conclusion] This study provides materials for understanding the blinding site of HSF1 on Arabidopsis thaliana chromosome, further laying a good foundation for revealing the regulatory mechanism and physiological function of HSF1.
基金Project (51074043) supported by the National Natural Science Foundation of ChinaProject (2011BAE03B01) supported by the National Technology Support Program of ChinaProject (N120409004) supported by the Fundamental Research Funds for Central Universities,China
文摘The composition and size distribution of cutting waste were characterized. The Si-rich powders were obtained from the cutting waste using a physical sedimentation process, and then further purified by removing impurity using acid leaching. The effects of process parameters such as acid leaching time, temperature and the ratio of solid to liquid on the purification efficiency were investigated, and the parameters were optimized. Afterwards, the high-purity Si ingot was obtained by melting the Si-rich powders in vacuum furnace. Finally, the high purity Si with 99.96%Si, 1.1×10^-6 boron （B）, and 4.0×10^-6 phosphorus （P） were obtained. The results indicate that it is feasible to extract high-purity Si, and further produce SoG-Si from the cutting slurry waste.
基金financial support from CAS Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences。
文摘The evolution of morphology, composition, thickness and corrosion resistance of the oxide film on pure Sn solder substrate submitted to high-temperature aging in 150 °C dry atmosphere was investigated. The results indicate that high-temperature aging accelerates the dehydration of Sn(OH)_(4)in the pre-existing native oxide film to form SnO_(2)and facilitates the oxidation of fresh Sn substrate, resulting in the gradual increase in oxide film thickness and surface roughness with prolonging aging time. However, the corrosion resistance of the film initially is enhanced and then deteriorated with an extending aging time. Besides, the formation and evolution mechanisms of the oxide film with aging time were discussed.
基金Project (Nos. 10472102 and 10432030) supported by the NationalNatural Science Foundation of China
文摘This paper considers the pure bending problem of simply supported transversely isotropic circular plates with elastic compliance coefficients being arbitrary functions of the thickness coordinate. First, the partial differential equation, which is satisfied by the stress functions for the axisymmetric deformation problem is derived. Then, stress functions are obtained by proper manipulation. The analytical expressions of axial force, bending moment and displacements are then deduced through integration. And then, stress functions are employed to solve problems of transversely isotropic functionally graded circular plate, with the integral constants completely determined from boundary conditions. An elasticity solution for pure bending problem, which coincides with the available solution when degenerated into the elasticity solutions for homogenous circular plate, is thus obtained. A numerical example is finally presented to show the effect of material inhomogeneity on the elastic field in a simply supported circular plate of transversely isotropic functionally graded material (FGM).
文摘Objective： To study the effect of surface configuration and roughness on the corrosion resistance of pure Titanium （Ti） after used in oral environment for half a year. Methods ：Three edentulous volunteers with healthy oral mucosa participated in an in vivo study. Four kinds of pure Ti testing pieces with different surface roughness were fixed in the polished surface of upper complete dentures and the other in the tissue surface of the dentures. After 6-month wearing the denture, dynamic polarization curves were traced with electrochemical method. Results：Ep and Ip of specimen used in oral cavity was higher than that left in air,which meant corrosion resistance falling. Compared to plane one ,Ecorr of wrinkly specimen was more positive,and Ep and Ip were more higher,so its corrosion resistance reduced. With the increase of surface roughness,Ep and Ip increased from 0.937 V and 1.810μA （Group Ⅱ） to 1.701 V and 2.252μA （Group Ⅳ）respectively,there was even no passivation in Group Ⅲ （which was the most coarse）,so proneness to corrosion enhanced. For specimen with the same surface roughness ,Ep and Ip of Group Ⅳ （1.701 V and 2.252 μA respectively） ,which was placed on polished surface of denture base,was higher than that on tissue surface（Group V , 1. 304 V, 1. 946μA）. Conclusion： From the perspective of corrosion behavior, wrinkly surface should not be adopted when pure Ti prosthesis is used,and surface roughness on the polishing surface of pure Ti prosthesis should be paid more attention,especially on clasps and connectors, where there is often more force to be exerted.
文摘In the past ^68Ge （Germanium-68） was purified with toxic organic solvents in liquid-liquid extractions making the product unacceptable by the FDA （food and drug Administration） for human use. The authors report initial studies utilizing three or four columns consisting of sequences of AG 1, AG50, Chelex 100 and/or Sephadex G25 resins. Five purification methods were examined and a separation consisting of the sequence： AG 1-Chelex100-Sephedex G25 provided 87% recovery of germanium. Fractionation of the elution resulted in high germanium concentrations.
文摘In the current study,an effort has been taken to manufacture and compare the characteristics of functionally graded tubes. Two samples have been produced with a commercially pure aluminium matrix reinforced by 10%(in weight) SiC and Al_(2)O_(3)with a 16 μm average size via horizontal centrifugal casting. In addition to microstructure analysis,the mechanical and wear characteristics have been investigated across the thickness of the produced tubes.The results showed that the addition of SiC and Al_(2)O_(3)particles relative to the unreinforced matrix(pure Al)significantly enhance the mechanical properties and wear resistance of the produced tubes. Thus,these tubes are the best choice for automobile applications.
文摘The dissimilar joining of CP-copper to 304 stainless steel was performed by gas tungsten arc welding process using different filler materials. The results indicated the formation of defect free joint by using copper filler material. But, the presence of some defects like solidification crack and lack of fusion caused decreasing tensile strength of other joints. In the optimum conditions, the tensile strength of the joint was 96% of the weaker material. Also, this joint was bent till to 180° without any macroscopic defects like separation, tearing or fracture. It was concluded that copper is a new and good candidate for gas tungsten arc welding of copper to 304 stainless steel.
文摘Chromaticity characteristics of several fluorescent dyes in cloth were studied in terms of chromaticity diagram. The dominant wavelength and color purity of the samples were calculated and chromaticity diagrams were drawn to provide countermeasures with which the perceptual color attributes such as hue and saturation are correlated.
文摘Using ultra high purity NaF-NaKCO3 in the Fluorescence spectrometry, determination of sub ppb levels of Uranium in the electronic materials has been achieved. The method could be applied to determination of Uranium in any electronic materials.
