The Fe3O4@SiO2 composite nanoparticles were obtained from as-synthesized magnetite (Fe3O4) nanoparticles through the modified St?ber method. Then, the Fe3O4 nanoparticles and Fe3O4@SiO2 composite nanoparticles were ch...The Fe3O4@SiO2 composite nanoparticles were obtained from as-synthesized magnetite (Fe3O4) nanoparticles through the modified St?ber method. Then, the Fe3O4 nanoparticles and Fe3O4@SiO2 composite nanoparticles were characterized by means of X-ray diffraction (XRD), Raman spectra, scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). Recently, the studies focus on how to improve the dispersion of composite particle and achieve good magnetic performance. Hence effects of the volume ratio of tetraethyl orthosilicate (TEOS) and magnetite colloid on the structural, morphological and magnetic properties of the composite nanoparticles were systematically investi-gated. The results revealed that the Fe3O4@SiO2 had better thermal stability and dispersion than the magnetite nanoparticles. Furthermore, the particle size and magnetic property of the Fe3O4@SiO2 composite nanoparticles can be adjusted by changing the volume ratio of TEOS and magnetite colloid.展开更多
Objective： To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods： Two crucial conditions （sodium chloride concentration and amount of the magnetic...Objective： To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods： Two crucial conditions （sodium chloride concentration and amount of the magnetic particles） were optimized and 8 different human whole blood samples were used to purify genomic DNA under the optimal condition. Then agarose gel electrophoresis and polymerase cbain reaction （PCR） were performed. Results： The optimal binding condition was 1.5 mol/L NaC1/10% PEG, and the optimal amount of Fe3O4/Au composite particles was 600μg. The yields of the genomic DNA from 100μl of different whole blood samples were 2-5 μg, and the ratio of A260/A280 was in the range of 1.70-1.90. The size of genomic DNA was about 23 kb and the PCR was valid. Conclusion： The purification system using Fe3O4/Au composite microparticles has advantages in high yield, high purity, ease of operating, time saving and avoiding centrifugation. The purified sample was found to function satisfactorily in PCR amplification.展开更多
The 1.5% Au/Fe2O3 catalysts prepared by an inverse co-precipitation method calcined at different temperatures was characterized by XRD, XPS, TEM, BET, and tested by CO selective oxidation in H2-rich gas. The results s...The 1.5% Au/Fe2O3 catalysts prepared by an inverse co-precipitation method calcined at different temperatures was characterized by XRD, XPS, TEM, BET, and tested by CO selective oxidation in H2-rich gas. The results show that the chemical composition and activity of the catalysts are greatly changed with the variation of calcination temperature. The catalyst Au/Fe2O3 calcined at 200℃, highly dispersed particles with the partially oxidized gold species on the support with the mean diameter of 3nm～5nm, displayes the best activity and selectivity of CO selective oxidation. However, the catalytic activity of Au/Fe2O3 decreases drastically with increasing calcination temperature due to the aggregation of metallic gold and bigger particle sizes. It is found that the catalytic behavior is related to the gold particle size but the nature of the support. On the basis of characterization data, in addition to the particle size of metallic gold, the oxidation states of gold are proven to be important for CO selective oxidation in H2-rich gas.展开更多
In order to modify inorganic particles as chromatic electrophoretic particles, an approach was designed and used to prepare Fe203 red electrophoretic particles. These Fe203-cationic hybrid nanoparticles （Fe203-CHNPs...In order to modify inorganic particles as chromatic electrophoretic particles, an approach was designed and used to prepare Fe203 red electrophoretic particles. These Fe203-cationic hybrid nanoparticles （Fe203-CHNPs）were prepared through Fe203 core covered with polymer shell which was composed of SiO2 and P （DMAEMA-co-HMA） by using atom transfer radical polymerization （ATRP）technique. The SiO：-coating could introduce the functional group on the surfaceof inorganic particles, through which the polymer shell could be formed by using ATRP tech- nique. The results of Fourier transform infrared spectra （FT-IR）, X-ray photoelectron spectroscopy （XPS） and thermal gravimetric analysis （TGA）confirmed the chemical compositions of Fe2O3-CHNPs; the images of transmission elec- tron microscopy （TEM） indicated the core-shell structure of Fe2O3-CHNPs; the measurements of dynamic light scatter- ing （DLS） showed a 253.7 nm average particle size with narrow size distribution; and the zeta potential measurements identified the high chargeability of Fe2O3-CHNPs. Furthermore, the resulting nanoparticles were successfully applied in the electrophoretic display cell, which demonstrated that it was an effective approach to preparing chromatic elec- trophoretic particles.展开更多
The relationship between the efficiency of NiO/Fe2O3 wet grinding and noisy-power dissipation was studied. The optimal grinding parameters were found as: a slurry water content of 64.10%-85.47%, ball number ratio of 3...The relationship between the efficiency of NiO/Fe2O3 wet grinding and noisy-power dissipation was studied. The optimal grinding parameters were found as: a slurry water content of 64.10%-85.47%, ball number ratio of 360/20, revolution speed of 300.9 r/min, powder-filling ratio of 10.88%, ball-filling ratio of 20.53%-23.88%, and grinding time of approximately 6 h. The discrete element method(DEM) was employed to analyze relationship between the noisy-power dissipation and the grinding efficiency, and equations describing the relationship were derived. The mean particle size of the ground powder decreased with a decrease in the degree of noisy-power dissipation, while the grinding efficiency and the amount of specific impact power used decreased with an increase in the degree of noisy-power dissipation.展开更多
Ni-Co-Fe2O3 composite coatings were electrodeposited using cetyltrimethylammonium bromide(CTAB)-modified Watt's nickel bath with Fe2O3 particles dispersed in it.The effects of the plating parameters on the chemica...Ni-Co-Fe2O3 composite coatings were electrodeposited using cetyltrimethylammonium bromide(CTAB)-modified Watt's nickel bath with Fe2O3 particles dispersed in it.The effects of the plating parameters on the chemical composition,structural and morphological characteristics of the electrodeposited Ni-Co-Fe2O3 composite coatings were investigated by energy dispersive X-ray(EDS) spectroscopy,X-ray diffractometry(XRD) and scanning electron microscopy(SEM).The results reveal that Fe2O3 particles can be codeposited in the Ni-Co matrix.The codeposition of Fe2O3 particles with Ni-Co is favoured at high Fe2O3 particle concentration and medium stirring,and the deposition of Co is favoured at high concentration of CTAB.Moreover,the study of the textural perfection of the deposits reveals that the presence of particles leads to the worsening of the quality of the observed <220> preferred orientation.Composites with high concentration of embedded particles exhibit a preferred crystal orientation of <111>.The more the embedded Fe2O3 particles in the metallic matrix,the smaller the sizes of the crystallite for the composite deposits.展开更多
Using Fe3O4 nano-particles as seeds, a new type of Fe3O4/Au composite particles with core/shell structure and diameter of about 170 nm was prepared by reduction of Au3+ with hydroxylamine in an aqueous solution. Parti...Using Fe3O4 nano-particles as seeds, a new type of Fe3O4/Au composite particles with core/shell structure and diameter of about 170 nm was prepared by reduction of Au3+ with hydroxylamine in an aqueous solution. Particle size analyzer and transmission electron micro-scope were used to analyze the size distribution and microstructure of the particles in different conditions. The result showed that the magnetically responsive property and suspension stability of Fe3O4 seeds as well as reduction conditions of Au3+ to Au0 are the main factors which are crucial for obtaining a colloid of the Fe3O4/Au composite particles with uniform particle dispersion, excellent stability, homogeneity in particle sizes, and effective response to an external magnet in aqueous suspension solutions. UV-Vis analysis revealed that there is a characteristic peak of Fe3O4/Au fluid. For particles with d(0.5)=168 nm, the lmax is 625 nm.展开更多
文摘The Fe3O4@SiO2 composite nanoparticles were obtained from as-synthesized magnetite (Fe3O4) nanoparticles through the modified St?ber method. Then, the Fe3O4 nanoparticles and Fe3O4@SiO2 composite nanoparticles were characterized by means of X-ray diffraction (XRD), Raman spectra, scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). Recently, the studies focus on how to improve the dispersion of composite particle and achieve good magnetic performance. Hence effects of the volume ratio of tetraethyl orthosilicate (TEOS) and magnetite colloid on the structural, morphological and magnetic properties of the composite nanoparticles were systematically investi-gated. The results revealed that the Fe3O4@SiO2 had better thermal stability and dispersion than the magnetite nanoparticles. Furthermore, the particle size and magnetic property of the Fe3O4@SiO2 composite nanoparticles can be adjusted by changing the volume ratio of TEOS and magnetite colloid.
基金Supported by the National High Technology Research and Development Program of China (2006AA020705)
文摘Objective： To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods： Two crucial conditions （sodium chloride concentration and amount of the magnetic particles） were optimized and 8 different human whole blood samples were used to purify genomic DNA under the optimal condition. Then agarose gel electrophoresis and polymerase cbain reaction （PCR） were performed. Results： The optimal binding condition was 1.5 mol/L NaC1/10% PEG, and the optimal amount of Fe3O4/Au composite particles was 600μg. The yields of the genomic DNA from 100μl of different whole blood samples were 2-5 μg, and the ratio of A260/A280 was in the range of 1.70-1.90. The size of genomic DNA was about 23 kb and the PCR was valid. Conclusion： The purification system using Fe3O4/Au composite microparticles has advantages in high yield, high purity, ease of operating, time saving and avoiding centrifugation. The purified sample was found to function satisfactorily in PCR amplification.
文摘The 1.5% Au/Fe2O3 catalysts prepared by an inverse co-precipitation method calcined at different temperatures was characterized by XRD, XPS, TEM, BET, and tested by CO selective oxidation in H2-rich gas. The results show that the chemical composition and activity of the catalysts are greatly changed with the variation of calcination temperature. The catalyst Au/Fe2O3 calcined at 200℃, highly dispersed particles with the partially oxidized gold species on the support with the mean diameter of 3nm～5nm, displayes the best activity and selectivity of CO selective oxidation. However, the catalytic activity of Au/Fe2O3 decreases drastically with increasing calcination temperature due to the aggregation of metallic gold and bigger particle sizes. It is found that the catalytic behavior is related to the gold particle size but the nature of the support. On the basis of characterization data, in addition to the particle size of metallic gold, the oxidation states of gold are proven to be important for CO selective oxidation in H2-rich gas.
文摘In order to modify inorganic particles as chromatic electrophoretic particles, an approach was designed and used to prepare Fe203 red electrophoretic particles. These Fe203-cationic hybrid nanoparticles （Fe203-CHNPs）were prepared through Fe203 core covered with polymer shell which was composed of SiO2 and P （DMAEMA-co-HMA） by using atom transfer radical polymerization （ATRP）technique. The SiO：-coating could introduce the functional group on the surfaceof inorganic particles, through which the polymer shell could be formed by using ATRP tech- nique. The results of Fourier transform infrared spectra （FT-IR）, X-ray photoelectron spectroscopy （XPS） and thermal gravimetric analysis （TGA）confirmed the chemical compositions of Fe2O3-CHNPs; the images of transmission elec- tron microscopy （TEM） indicated the core-shell structure of Fe2O3-CHNPs; the measurements of dynamic light scatter- ing （DLS） showed a 253.7 nm average particle size with narrow size distribution; and the zeta potential measurements identified the high chargeability of Fe2O3-CHNPs. Furthermore, the resulting nanoparticles were successfully applied in the electrophoretic display cell, which demonstrated that it was an effective approach to preparing chromatic elec- trophoretic particles.
基金supported by the Inert Anode Material Production and Application in Electrolytic Production of Aluminium program of the Yunnan Aluminium Yonxin Aluminium Co. Ltd
文摘The relationship between the efficiency of NiO/Fe2O3 wet grinding and noisy-power dissipation was studied. The optimal grinding parameters were found as: a slurry water content of 64.10%-85.47%, ball number ratio of 360/20, revolution speed of 300.9 r/min, powder-filling ratio of 10.88%, ball-filling ratio of 20.53%-23.88%, and grinding time of approximately 6 h. The discrete element method(DEM) was employed to analyze relationship between the noisy-power dissipation and the grinding efficiency, and equations describing the relationship were derived. The mean particle size of the ground powder decreased with a decrease in the degree of noisy-power dissipation, while the grinding efficiency and the amount of specific impact power used decreased with an increase in the degree of noisy-power dissipation.
基金Project(2005CB623703) supported by the National Key Basic Research Program of ChinaProject(50474051) supported by the National Natural Science Foundation of China+2 种基金Project(CX2009B032) supported by Innovation Foundation for Postgraduate of Hunan Province of China Project(ZKJ2009024) supported by the Precious Apparatus Open Share Foundation of Central South University, ChinaProject(2009ybfz02) supported by Excellent Doctor Support Fund of Central South University,China
文摘Ni-Co-Fe2O3 composite coatings were electrodeposited using cetyltrimethylammonium bromide(CTAB)-modified Watt's nickel bath with Fe2O3 particles dispersed in it.The effects of the plating parameters on the chemical composition,structural and morphological characteristics of the electrodeposited Ni-Co-Fe2O3 composite coatings were investigated by energy dispersive X-ray(EDS) spectroscopy,X-ray diffractometry(XRD) and scanning electron microscopy(SEM).The results reveal that Fe2O3 particles can be codeposited in the Ni-Co matrix.The codeposition of Fe2O3 particles with Ni-Co is favoured at high Fe2O3 particle concentration and medium stirring,and the deposition of Co is favoured at high concentration of CTAB.Moreover,the study of the textural perfection of the deposits reveals that the presence of particles leads to the worsening of the quality of the observed <220> preferred orientation.Composites with high concentration of embedded particles exhibit a preferred crystal orientation of <111>.The more the embedded Fe2O3 particles in the metallic matrix,the smaller the sizes of the crystallite for the composite deposits.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20273035)the National High Technology Research and Development Program of China(863 Program)(Grant Nos.2002AA2Z2031 and 2001AA224032)the Science and Technology Program of Xi'an(Grant No.GG200148).
文摘Using Fe3O4 nano-particles as seeds, a new type of Fe3O4/Au composite particles with core/shell structure and diameter of about 170 nm was prepared by reduction of Au3+ with hydroxylamine in an aqueous solution. Particle size analyzer and transmission electron micro-scope were used to analyze the size distribution and microstructure of the particles in different conditions. The result showed that the magnetically responsive property and suspension stability of Fe3O4 seeds as well as reduction conditions of Au3+ to Au0 are the main factors which are crucial for obtaining a colloid of the Fe3O4/Au composite particles with uniform particle dispersion, excellent stability, homogeneity in particle sizes, and effective response to an external magnet in aqueous suspension solutions. UV-Vis analysis revealed that there is a characteristic peak of Fe3O4/Au fluid. For particles with d(0.5)=168 nm, the lmax is 625 nm.
