Supermacroporous composite cryogels embedded with SiO2 nanoparticles were prepared by radical cryogenic copolymerization of the reactive monomer mixture of acrylamide（AAm） and N,N-methylene-bis-acrylamide（MBAAm） c...Supermacroporous composite cryogels embedded with SiO2 nanoparticles were prepared by radical cryogenic copolymerization of the reactive monomer mixture of acrylamide（AAm） and N,N-methylene-bis-acrylamide（MBAAm） containing SiO2 nanoparticles（mass ratios of nanoparticles to the monomer AAm from 0.01 to 0.08） under the freezing-temperature variation condition in glass columns.The properties of these composite cryogels were measured.The height equivalent to theoretical plate（HETP） of the cryogel beds at different liquid flow rates was determined by residence time distribution（RTD） using tracer pulse-response method.The composite cryogel matrix embedded with the mass fraction of SiO2 nanoparticles of 0.02 presented the best properties and was employed in the following graft polymerization.Chromatographic process of lysozyme in the composite cryogel grafted with 2-acrylamido-2-methyl-1-propanesulfonic acid（AMPSA） was carried out to evaluate the protein breakthrough and elution characteristics.The chromatography can be carried out at relatively high superficial velocity,i.e.,15 cm·min-1,indicating the satisfactory mechanical strength due to the embedded nanoparticles.展开更多
Objective The effect of the silica nanoparticles（SNs） on lungs injury in rats was investigated to evaluate the toxicity and possible mechanisms for SNs.Methods Male Wistar rats were instilled intratracheally with 1 ...Objective The effect of the silica nanoparticles（SNs） on lungs injury in rats was investigated to evaluate the toxicity and possible mechanisms for SNs.Methods Male Wistar rats were instilled intratracheally with 1 mL of saline containing 6.25,12.5,and 25.0 mg of SNs or 25.0 mg of microscale SiO_2 particles suspensions for 30 d,were then sacrificed.Histopathological and ultrastructural change in lungs,and chemical components in the urine excretions were investigated by light microscope,TEM and EDS.MDA,NO and hydroxyproline（Hyp） in lung homogenates were quantified by spectrophotometry.Contents of TNF-α,TGF-β1,IL-1β,and MMP-2 in lung tissue were determined by immunohistochemistry staining.Results There is massive excretion of Si substance in urine.The SNs lead pulmonary lesions of rise in lung/body coefficients,lung inflammation,damaged alveoli,granuloma nodules formation,and collagen metabolized perturbation,and lung tissue damage is milder than those of microscale SiO_2 particles.The SNs also cause increase lipid peroxidation and high expression of cytokines.Conclusion The SNs result into pulmonary fibrosis by means of increase lipid peroxidation and high expression of cytokines.Milder effect of the SNs on pulmonary fibrosis comparing to microscale SiO_2 particles is contributed to its elimination from urine due to their ultrafine particle size.展开更多
Tetrathiafulvalene（TTF） was doped in an SiO2 network and the resulting nanocompesite was used as a mediator for the selective detection of glucose. The uniform TTF-doped silica（TIT@SiO2 ） nanoparticles were prepar...Tetrathiafulvalene（TTF） was doped in an SiO2 network and the resulting nanocompesite was used as a mediator for the selective detection of glucose. The uniform TTF-doped silica（TIT@SiO2 ） nanoparticles were prepared by the water-in-oil（W/O） microemulsion method, and were characterized by transmission electron microscopy（TEM）. The core-shell structure TTF@ SiO2 could prevent TIT from leaching out into an aqueous solution. Combined with chitosan （CHIT）, which serves as a scaffold for glucose oxidase and nanocomposite immobilization, the GCE/TTF@ SiO2- CHIT-GOx biosensor was developed. Under optimal conditions, the biosensors exhibit a linear range of 1.0 × 10^-5 5 × 10^-3 mol/L with a detection limit down to 5.0 μmol/L（S/N = 3 ）. The excellent selectivity, sensitivity, and stability of the glucose biosensor show its potential for practical applications.展开更多
The Ag/SiO2 nanoparticles had been successfully synthesized. The Ag/SiO2 nano- particles can be an excellent catalyst for the synthesis of ultraviolet absorber benzotriazole by catalytic hydrogenation. The synthesis r...The Ag/SiO2 nanoparticles had been successfully synthesized. The Ag/SiO2 nano- particles can be an excellent catalyst for the synthesis of ultraviolet absorber benzotriazole by catalytic hydrogenation. The synthesis route is very efficient with less pollution and excellent yields. It is also easy to industrialized production.展开更多
One of the most important safety features of nuclear facilities is the shielding material used to protect the operating personnel from radiation exposure. The most common materials used in radiation shielding are conc...One of the most important safety features of nuclear facilities is the shielding material used to protect the operating personnel from radiation exposure. The most common materials used in radiation shielding are concretes. In this study, a Monte Carlo N-Particle eXtended code is used to calculate the gamma-ray attenuation coefficients and dose rates for a new concrete material composed of MnFe_2O_4 nanoparticles, which is then compared with the theoretical and experimental results obtained for a SiO_2 nanoparticle concrete material. According to the results, the average relative differences between the simulations and the theoretical and experimental results for the linear attenuation coefficient(l) in the SiO_2 nanoparticle materials are 6.4% and 5.5%, respectively. By increasing the SiO_2 content up to 1.5% and the temperature of MnFe_2O_4 up to 673 K, l is increased for all energies. In addition, the photon dose rate decreases up to 9.2% and3.7% for MnFe_2O_4 and SiO_2 for gamma-ray energies of0.511 and 1.274 MeV, respectively. Therefore, it was concluded that the addition of SiO_2 and MnFe_2O_4 nanoparticles to concrete improves its nuclear properties and could lead to it being more useful in radiation shielding.展开更多
High quality Zn0.5CoxFe2.5−xO4(x=0,0.05,0.1,0.15)serial magnetic nanoparticles with single cubic structures were prepared by the modified thermal decomposition method,and Zn0.5CoxFe2.5−xO4/SiO2 composite magnetic nano...High quality Zn0.5CoxFe2.5−xO4(x=0,0.05,0.1,0.15)serial magnetic nanoparticles with single cubic structures were prepared by the modified thermal decomposition method,and Zn0.5CoxFe2.5−xO4/SiO2 composite magnetic nanoparticles were prepared by surface modification of SiO2.The magnetic anisotropy of the sample increases with the increase of the doping amount of Co2+.When the doping amount is 0.1,the sample shows the transition from superparamagnetism to ferrimagnetism at room temperature.In the Zn0.5CoxFe2.5−xO4/SiO2 serial samples,the maximum value of specific loss power(SLP)with 1974 W/gmetal can also be found at doping amount of x=0.1.The composite nanoparticles are expected to be an excellent candidate for clinical magnetic hyperthermia.展开更多
Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carri...Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carried out on the Cu and Zr K-edge. Under reaction conditions, Cu remains metallic, while Zr is present in three types of coordination environment associated with 1) bulk ZrO2, 2) coordinatively saturated and 3) unsaturated Zr(Ⅳ) surface sites. The amount of coordinatively unsaturated Zr surface sites can be quantified by linear combination fit of reference X-Ray absorption near edge structure (XANES) spectra and its amount correlates with CH3OH formation rates, thus indicating the importance of Zr(Ⅳ) Lewis acid surface sites in driving the selectivity toward CH3OH. This finding is consistent with the proposed mechanism, where CO2 is hydrogenated at the interface between the Cu nanoparticles that split H2 and Zr(Ⅳ) surface sites that stabilizes reaction intermediates.展开更多
The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the fi...The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the filling content of nano-SiO2 particles on the mechanical properties of the dental composites was studied as well. The experimental results showed that the incorporation of the nano-SiO2 particles at low concentrations (up to 10 wt.%) can apparently increase the hardness and elastic modulus of the dental rein composites. The plasticity index indicates a best elastic recovery capability at a proper amount (4 wt.%) of the nanoparticles. Combined with the infrared spectrum, the mechanical enhancement mechanisms of the dental resin composites were analyzed.展开更多
M-type hexaferrites BaLaxFe12-xO19 powders were synthesized by sol-gel method in the presence of SiO2 nanoparticles. The X-ray diffraction patterns of BaLaxFe12-xO19/SiO2 calcined at 1000℃manifest that all the specie...M-type hexaferrites BaLaxFe12-xO19 powders were synthesized by sol-gel method in the presence of SiO2 nanoparticles. The X-ray diffraction patterns of BaLaxFe12-xO19/SiO2 calcined at 1000℃manifest that all the species have hexagonal crystal structure and no diffraction peaks of SiO2 are found. The structure of BaLaxFe12-xO19 seems uniform at different La doping dosage. Fourier transform infrared (FTIR) proves the co-existence of SiO2 and ferrites in the produc-ts. The addition of SiO2 nanoparticles promotes the formation of more homogeneous and finer ferrite crystal, as proved by scanning electron microscopy (SEM). Compared with BaLa0.5Fe11.5O19 powders synthesized without SiO2 nanoparticles, those synthesized in the presence of SiO2 nanoparticles present in smaller powder size and similar structure.展开更多
Colloidal dispersion of nano-Ru/SiO2 in PEG （polyethylene glycol, M.W.=400） was used for benzene hydrogenation. The system has the features of easy catalyst＇s recycling and high catalyst stability.
An effective surface enhanced Raman scattering（SERS） substrate is designed and fabricated by synthesis of Si O2 nanorods array via glancing angle deposition, followed by coating Au nanoparticles onto Si O2 surface i...An effective surface enhanced Raman scattering（SERS） substrate is designed and fabricated by synthesis of Si O2 nanorods array via glancing angle deposition, followed by coating Au nanoparticles onto Si O2 surface in order to create numerous ＂hot spots＂. The detecting sensitivity of such substrate could be optimized by simply adjusting the deposition time of Au. Thus, it can be used for detection of Rhodamine 6G at concentration as low as 10^-9M. Furthermore, our SERS substrate is applied to detect 5 μg/g polychlorinated biphenyls in soil sample, which proves its potential for trace environmental pollutants detection.展开更多
基金Supported by the National Natural Science Foundation of China（20876145） the Natural Science Foundation of Zhejiang Province（Y4080329）
文摘Supermacroporous composite cryogels embedded with SiO2 nanoparticles were prepared by radical cryogenic copolymerization of the reactive monomer mixture of acrylamide（AAm） and N,N-methylene-bis-acrylamide（MBAAm） containing SiO2 nanoparticles（mass ratios of nanoparticles to the monomer AAm from 0.01 to 0.08） under the freezing-temperature variation condition in glass columns.The properties of these composite cryogels were measured.The height equivalent to theoretical plate（HETP） of the cryogel beds at different liquid flow rates was determined by residence time distribution（RTD） using tracer pulse-response method.The composite cryogel matrix embedded with the mass fraction of SiO2 nanoparticles of 0.02 presented the best properties and was employed in the following graft polymerization.Chromatographic process of lysozyme in the composite cryogel grafted with 2-acrylamido-2-methyl-1-propanesulfonic acid（AMPSA） was carried out to evaluate the protein breakthrough and elution characteristics.The chromatography can be carried out at relatively high superficial velocity,i.e.,15 cm·min-1,indicating the satisfactory mechanical strength due to the embedded nanoparticles.
基金supported by the National Natural Science Foundation of China(Grant No.81273046)the Fundamental Research Funds for the Central Universitiesthe Preventive Medicine Research Projects of Jiangsu Province(Grant No.Y2012039)
文摘Objective The effect of the silica nanoparticles（SNs） on lungs injury in rats was investigated to evaluate the toxicity and possible mechanisms for SNs.Methods Male Wistar rats were instilled intratracheally with 1 mL of saline containing 6.25,12.5,and 25.0 mg of SNs or 25.0 mg of microscale SiO_2 particles suspensions for 30 d,were then sacrificed.Histopathological and ultrastructural change in lungs,and chemical components in the urine excretions were investigated by light microscope,TEM and EDS.MDA,NO and hydroxyproline（Hyp） in lung homogenates were quantified by spectrophotometry.Contents of TNF-α,TGF-β1,IL-1β,and MMP-2 in lung tissue were determined by immunohistochemistry staining.Results There is massive excretion of Si substance in urine.The SNs lead pulmonary lesions of rise in lung/body coefficients,lung inflammation,damaged alveoli,granuloma nodules formation,and collagen metabolized perturbation,and lung tissue damage is milder than those of microscale SiO_2 particles.The SNs also cause increase lipid peroxidation and high expression of cytokines.Conclusion The SNs result into pulmonary fibrosis by means of increase lipid peroxidation and high expression of cytokines.Milder effect of the SNs on pulmonary fibrosis comparing to microscale SiO_2 particles is contributed to its elimination from urine due to their ultrafine particle size.
基金Supported by the National Natural Science Foundation of China(No. 20305007) and Doctoral Foundation of China Ministry ofEducation(No. 20030269014)
文摘Tetrathiafulvalene（TTF） was doped in an SiO2 network and the resulting nanocompesite was used as a mediator for the selective detection of glucose. The uniform TTF-doped silica（TIT@SiO2 ） nanoparticles were prepared by the water-in-oil（W/O） microemulsion method, and were characterized by transmission electron microscopy（TEM）. The core-shell structure TTF@ SiO2 could prevent TIT from leaching out into an aqueous solution. Combined with chitosan （CHIT）, which serves as a scaffold for glucose oxidase and nanocomposite immobilization, the GCE/TTF@ SiO2- CHIT-GOx biosensor was developed. Under optimal conditions, the biosensors exhibit a linear range of 1.0 × 10^-5 5 × 10^-3 mol/L with a detection limit down to 5.0 μmol/L（S/N = 3 ）. The excellent selectivity, sensitivity, and stability of the glucose biosensor show its potential for practical applications.
基金supported by research fund of Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province (No. AE201127)
文摘The Ag/SiO2 nanoparticles had been successfully synthesized. The Ag/SiO2 nano- particles can be an excellent catalyst for the synthesis of ultraviolet absorber benzotriazole by catalytic hydrogenation. The synthesis route is very efficient with less pollution and excellent yields. It is also easy to industrialized production.
文摘One of the most important safety features of nuclear facilities is the shielding material used to protect the operating personnel from radiation exposure. The most common materials used in radiation shielding are concretes. In this study, a Monte Carlo N-Particle eXtended code is used to calculate the gamma-ray attenuation coefficients and dose rates for a new concrete material composed of MnFe_2O_4 nanoparticles, which is then compared with the theoretical and experimental results obtained for a SiO_2 nanoparticle concrete material. According to the results, the average relative differences between the simulations and the theoretical and experimental results for the linear attenuation coefficient(l) in the SiO_2 nanoparticle materials are 6.4% and 5.5%, respectively. By increasing the SiO_2 content up to 1.5% and the temperature of MnFe_2O_4 up to 673 K, l is increased for all energies. In addition, the photon dose rate decreases up to 9.2% and3.7% for MnFe_2O_4 and SiO_2 for gamma-ray energies of0.511 and 1.274 MeV, respectively. Therefore, it was concluded that the addition of SiO_2 and MnFe_2O_4 nanoparticles to concrete improves its nuclear properties and could lead to it being more useful in radiation shielding.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51771124,51571146,and 51701130)。
文摘High quality Zn0.5CoxFe2.5−xO4(x=0,0.05,0.1,0.15)serial magnetic nanoparticles with single cubic structures were prepared by the modified thermal decomposition method,and Zn0.5CoxFe2.5−xO4/SiO2 composite magnetic nanoparticles were prepared by surface modification of SiO2.The magnetic anisotropy of the sample increases with the increase of the doping amount of Co2+.When the doping amount is 0.1,the sample shows the transition from superparamagnetism to ferrimagnetism at room temperature.In the Zn0.5CoxFe2.5−xO4/SiO2 serial samples,the maximum value of specific loss power(SLP)with 1974 W/gmetal can also be found at doping amount of x=0.1.The composite nanoparticles are expected to be an excellent candidate for clinical magnetic hyperthermia.
基金E.L.,K.L.,P.W.,and S.T.are supported by the SCCER-Heat and Energy Storage program
文摘Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carried out on the Cu and Zr K-edge. Under reaction conditions, Cu remains metallic, while Zr is present in three types of coordination environment associated with 1) bulk ZrO2, 2) coordinatively saturated and 3) unsaturated Zr(Ⅳ) surface sites. The amount of coordinatively unsaturated Zr surface sites can be quantified by linear combination fit of reference X-Ray absorption near edge structure (XANES) spectra and its amount correlates with CH3OH formation rates, thus indicating the importance of Zr(Ⅳ) Lewis acid surface sites in driving the selectivity toward CH3OH. This finding is consistent with the proposed mechanism, where CO2 is hydrogenated at the interface between the Cu nanoparticles that split H2 and Zr(Ⅳ) surface sites that stabilizes reaction intermediates.
文摘The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the filling content of nano-SiO2 particles on the mechanical properties of the dental composites was studied as well. The experimental results showed that the incorporation of the nano-SiO2 particles at low concentrations (up to 10 wt.%) can apparently increase the hardness and elastic modulus of the dental rein composites. The plasticity index indicates a best elastic recovery capability at a proper amount (4 wt.%) of the nanoparticles. Combined with the infrared spectrum, the mechanical enhancement mechanisms of the dental resin composites were analyzed.
基金Project supported by Fund for Harbin Young Scholars (2005AFQ X J 0 31)
文摘M-type hexaferrites BaLaxFe12-xO19 powders were synthesized by sol-gel method in the presence of SiO2 nanoparticles. The X-ray diffraction patterns of BaLaxFe12-xO19/SiO2 calcined at 1000℃manifest that all the species have hexagonal crystal structure and no diffraction peaks of SiO2 are found. The structure of BaLaxFe12-xO19 seems uniform at different La doping dosage. Fourier transform infrared (FTIR) proves the co-existence of SiO2 and ferrites in the produc-ts. The addition of SiO2 nanoparticles promotes the formation of more homogeneous and finer ferrite crystal, as proved by scanning electron microscopy (SEM). Compared with BaLa0.5Fe11.5O19 powders synthesized without SiO2 nanoparticles, those synthesized in the presence of SiO2 nanoparticles present in smaller powder size and similar structure.
基金Thanks the financial support from the National Natural Science Foundation of China （No. 20376013）Fok Ying Tung Education Foundation （No. 91071） Specialized Research Fund for the Doctoral Program Foundation of Higher Education （No. 20020141004）.
文摘Colloidal dispersion of nano-Ru/SiO2 in PEG （polyethylene glycol, M.W.=400） was used for benzene hydrogenation. The system has the features of easy catalyst＇s recycling and high catalyst stability.
基金supported by the National Basic Research Program of China(Grant No.2013CB934301)the National Natural Science Foundation of China(Grant No.50931002)+1 种基金the Research Project of Chinese Ministry of Education(Grant No.113007A)the Initiative Scientific Research Program of Tsinghua University,China
文摘An effective surface enhanced Raman scattering（SERS） substrate is designed and fabricated by synthesis of Si O2 nanorods array via glancing angle deposition, followed by coating Au nanoparticles onto Si O2 surface in order to create numerous ＂hot spots＂. The detecting sensitivity of such substrate could be optimized by simply adjusting the deposition time of Au. Thus, it can be used for detection of Rhodamine 6G at concentration as low as 10^-9M. Furthermore, our SERS substrate is applied to detect 5 μg/g polychlorinated biphenyls in soil sample, which proves its potential for trace environmental pollutants detection.
