A novel polymer/SiO2 hybrid emulsion(PAES)was prepared by directly mixing colloidal silica with polyacrylate emulsion(PAE)modified by a saline coupling agent.The sol-gel-derived thin films were obtained by addition of...A novel polymer/SiO2 hybrid emulsion(PAES)was prepared by directly mixing colloidal silica with polyacrylate emulsion(PAE)modified by a saline coupling agent.The sol-gel-derived thin films were obtained by addition of co-solvents into the PAES.The effects ofγ-methacryloxypropyltrimethoxysilane(KH-570)content and co-solvent on the properties of PAES films were investigated.Dynamic laser scattering(DLS)data indicate that the average diameter of PAES(96 nm)is slightly larger than that of PAE(89 nm).Transmission electron microscopy (TEM)photo discloses that colloidal silica particles are dispersed uniformly around polyacrylate particles and some of the colloidal silica particles are adsorbed on the surface of PAE particles.The crosslinking degree data and Fourier transform infrared(FT-IR)spectra confirm that the chemical structure of the PAES is changed to form Si-O-Si-polymer crosslinking networks during the film formation.Atomic force microscope(AFM)photos show the solvent induced sol-gel process of colloidal silica and the Si-based polymer distribution on the film surface of the dried PAES.Thermogravimetric analysis(TGA)curves demonstrate that the PAES films display much better thermal stability than PAE.展开更多
Calcium carbonate （CaCO3） crystals in their preferred orientation were obtained in BG11 culture media inoculated with Synechocystis sp. PCC6803 （inoculated BG11）. In this study, the features of calcium carbonate d...Calcium carbonate （CaCO3） crystals in their preferred orientation were obtained in BG11 culture media inoculated with Synechocystis sp. PCC6803 （inoculated BG11）. In this study, the features of calcium carbonate deposition were investigated. Inoculated BGll in different calcium ion concentrations was used for the experimental group, while the BGll culture medium was used for the control group. The surface morphologies of the calcium carbonate deposits in the experimental and control groups were determined by scanning and transmission electron microscopy. The deposits were analyzed by electronic probe micro-analysis, Fourier transform infrared spectrum, X-ray diffraction, thermal gravimetric analysis and differential scanning calorimetry. The results show that the surfaces of the crystals in the experimental group were hexahedral in a scaly pattern. The particle sizes were micrometer-sized and larger than those in the control group. The deposits of the control group contained calcium （Ca）, carbon （C）, oxygen （O）, phosphorus （P）, iron （Fe）, copper （Cu）, zinc （Zn）, and other elements. The deposits in the experimental group contained Ca, C, and O only. The deposits of both groups contained calcite. The thermal decomposition temperature of the deposits in the control group was lower than those in the experimental group. It showed that the CaCO3 deposits of the experimental group had higher thermal stability than those of the control group. This may be due to the secondary metabolites produced by the algae cells, which affect the carbonate crystal structure and result in a close-packed structure. The algae cells that remained after thermal weight loss were heavier in higher calcium concentrations in BGll culture media. There may be more calcium- containing crystals inside and outside of these cells. These results shall be beneficial for understanding the formation mechanism of carbonate minerals.展开更多
In this work, the authors present a study of dye absorption in TiO2 doped with CNTs （carbon nanotubes）. Absorption decreases exponentially with the increase of CNTs in the film, while morphological characterization,...In this work, the authors present a study of dye absorption in TiO2 doped with CNTs （carbon nanotubes）. Absorption decreases exponentially with the increase of CNTs in the film, while morphological characterization, conducted by SEM （scanning electron microscope） and TEM （transmission electron microscope） microscopes, suggests that this behavior is strongly related to morphological structure of grown films. For CNTs amounts greater than 1%, the authors observe the formation of CNTs clusters randomly distribute on TiO2 bulk, which strongly reduces the film porosity quenching the dye absorption. Comparison with optical properties of CNT/TiO2 filmstudied in the previous work, suggest that the best level of doping is with 0.5% of CNTs. FTIR （Fourier transform infrared spectroscopy） measurements conducted on a series of pristine and doped samples clearly indicate the absence of change in allotropic species of TiO2, while AFM （atomic force microscope） analysis indicates that the sample roughness strongly changes with doping, preventing the dye adsorption. Finally, measurements of cell efficiency indicate an increase of 5% in cells with 0.5% of CNT doping and a decrease for greater values.展开更多
A facile method is proposed for the synthesis of reduced graphene oxide nanosheets （RGONS） and Au nanoparticle-reduced graphene oxide nanosheet （Au-RGONS） hybrid materials, using graphene oxide （GO） as precursor...A facile method is proposed for the synthesis of reduced graphene oxide nanosheets （RGONS） and Au nanoparticle-reduced graphene oxide nanosheet （Au-RGONS） hybrid materials, using graphene oxide （GO） as precursor and sodium citrate as reductant and stabilizer. The resulting RGONS and Au-RGONS hybrid materials were characterized by UV-vis spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, atomic force microscopy, transmission electron microscopy, and X-ray diffraction. It was found that the RGONS and Au-RGONS hybrid materials formed stable colloidal dispersions through hydrogen bonds between the residual oxygen-containing functionalities on the surface of RGONS and the hydroxyl/carboxyl groups of sodium citrate. The electrochemical responses of RGONS and Au-RGONS hybrid material-modified glassy carbon electrodes （GCE） to three kinds of biomolecules were investigated, and all of them showed a remarkable increase in electrochemical performance relative to a bare GCE.展开更多
Water-soluble gelatin-PbS bionanocomposites （BNCs） were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy （TEM）, X-ray diffrac...Water-soluble gelatin-PbS bionanocomposites （BNCs） were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, UV-vis absorption spectra （UV-vis）, Fourier transform infrared spectra （FT-IR） and circular dichroism （CD）. FT-IR data were used to envis- age the binding of PbS particles with oxygen atoms of carbonyl groups of gelatin molecule. The possible integration mechanism between gelatin and PbS was discussed in detail. The effect of Pb2＋ and PbS on the conformations of gelatin has also been analyzed by means of UV-vis, CD and FT-IR spectra, resulting in less c^-helix content and more open structures （[3-sheet, r-turn, or expanded）. A new formula to calculate the association constant was proposed according to the relationship between the absorbance of gelatin-PbS BNCs and the free concentration of PbS, and apparent association constants K （298/303/308 K： 3.11/2.00/1.60 × 10^6 tool/L） at three different temperatures were calculated based on this formula. Thermodynamic parameters such as AG^θ, △Hθ and △S^θ were also determined. The results of the thermodynamic investigations indicated that the reaction was spontaneous （AG^θ 〈 0）, and enthalpy-driven （△H^8 〈 0）.展开更多
Hydrogenated microcrystalline silicon （mc-Si：H） thin films were deposited by inductively coupled plasma assistant magnetron sputtering （ICP-MS） in an Ar-H2 gas mixture. The role of ion bombardment in the growth o...Hydrogenated microcrystalline silicon （mc-Si：H） thin films were deposited by inductively coupled plasma assistant magnetron sputtering （ICP-MS） in an Ar-H2 gas mixture. The role of ion bombardment in the growth of mc-Si：H films was studied with increasing negative bias voltages on the substrate holder from 0 to -100 V. Raman scattering, X-ray diffraction （XRD）, Fourier transform infrared （FTIR） spectroscopy and transmission electron microscopy （TEM） were performed to investigate the microstructure changes of deposited Si films. Raman scattering showed that the high energy ion bombardment resulted in crystalline degradation of Si films. The XRD results showed the decrease and even elimination of preferential growth orientation of crystalline Si films with ion bombardment energy increase. The SiH bonding configuration changes and the increase of bonded hydrogen concentration were determined with the analysis of FTIR spectra. Furthermore, the dramatic evolution of cross-sectional morphology of Si thin films was detected by TEM observation.展开更多
基金Supported by the Program for New Century Excellent Talents in University（NCET-08-0204） National Natural Science Foundation of China（20976060） the Scientific Research Foundation for the Returned Overseas Chinese Scholars State Edu-cation Ministry （China）
文摘A novel polymer/SiO2 hybrid emulsion(PAES)was prepared by directly mixing colloidal silica with polyacrylate emulsion(PAE)modified by a saline coupling agent.The sol-gel-derived thin films were obtained by addition of co-solvents into the PAES.The effects ofγ-methacryloxypropyltrimethoxysilane(KH-570)content and co-solvent on the properties of PAES films were investigated.Dynamic laser scattering(DLS)data indicate that the average diameter of PAES(96 nm)is slightly larger than that of PAE(89 nm).Transmission electron microscopy (TEM)photo discloses that colloidal silica particles are dispersed uniformly around polyacrylate particles and some of the colloidal silica particles are adsorbed on the surface of PAE particles.The crosslinking degree data and Fourier transform infrared(FT-IR)spectra confirm that the chemical structure of the PAES is changed to form Si-O-Si-polymer crosslinking networks during the film formation.Atomic force microscope(AFM)photos show the solvent induced sol-gel process of colloidal silica and the Si-based polymer distribution on the film surface of the dried PAES.Thermogravimetric analysis(TGA)curves demonstrate that the PAES films display much better thermal stability than PAE.
基金Supported by the National Natural Science Foundation of China(Nos.40972043,41040018,41210104058,21176145,41372108,41302079)the Higher Educational Science and Technology Program of Shandong Province(No.J10LC15)+4 种基金the China Postdoctoral Science Foundation(No.2013M540560)the Program for Scientific Research Innovation Team in Colleges and Universities of Shandong Province,and SDUST Research Fund(No.2010KYTD103)the Open Project of Key Lab of Marine Bioactive Substance and Modern Analytical Technique,State Oceanic Administration,China(No.MBSMAT-2012-03)the Scientific and Technological Program of Qingdao(No.13-1-4-232-jch)the Domestic Visiting Scholar Program for Young Core Teachers in Shandong Universities,Shandong Province,China
文摘Calcium carbonate （CaCO3） crystals in their preferred orientation were obtained in BG11 culture media inoculated with Synechocystis sp. PCC6803 （inoculated BG11）. In this study, the features of calcium carbonate deposition were investigated. Inoculated BGll in different calcium ion concentrations was used for the experimental group, while the BGll culture medium was used for the control group. The surface morphologies of the calcium carbonate deposits in the experimental and control groups were determined by scanning and transmission electron microscopy. The deposits were analyzed by electronic probe micro-analysis, Fourier transform infrared spectrum, X-ray diffraction, thermal gravimetric analysis and differential scanning calorimetry. The results show that the surfaces of the crystals in the experimental group were hexahedral in a scaly pattern. The particle sizes were micrometer-sized and larger than those in the control group. The deposits of the control group contained calcium （Ca）, carbon （C）, oxygen （O）, phosphorus （P）, iron （Fe）, copper （Cu）, zinc （Zn）, and other elements. The deposits in the experimental group contained Ca, C, and O only. The deposits of both groups contained calcite. The thermal decomposition temperature of the deposits in the control group was lower than those in the experimental group. It showed that the CaCO3 deposits of the experimental group had higher thermal stability than those of the control group. This may be due to the secondary metabolites produced by the algae cells, which affect the carbonate crystal structure and result in a close-packed structure. The algae cells that remained after thermal weight loss were heavier in higher calcium concentrations in BGll culture media. There may be more calcium- containing crystals inside and outside of these cells. These results shall be beneficial for understanding the formation mechanism of carbonate minerals.
文摘In this work, the authors present a study of dye absorption in TiO2 doped with CNTs （carbon nanotubes）. Absorption decreases exponentially with the increase of CNTs in the film, while morphological characterization, conducted by SEM （scanning electron microscope） and TEM （transmission electron microscope） microscopes, suggests that this behavior is strongly related to morphological structure of grown films. For CNTs amounts greater than 1%, the authors observe the formation of CNTs clusters randomly distribute on TiO2 bulk, which strongly reduces the film porosity quenching the dye absorption. Comparison with optical properties of CNT/TiO2 filmstudied in the previous work, suggest that the best level of doping is with 0.5% of CNTs. FTIR （Fourier transform infrared spectroscopy） measurements conducted on a series of pristine and doped samples clearly indicate the absence of change in allotropic species of TiO2, while AFM （atomic force microscope） analysis indicates that the sample roughness strongly changes with doping, preventing the dye adsorption. Finally, measurements of cell efficiency indicate an increase of 5% in cells with 0.5% of CNT doping and a decrease for greater values.
文摘A facile method is proposed for the synthesis of reduced graphene oxide nanosheets （RGONS） and Au nanoparticle-reduced graphene oxide nanosheet （Au-RGONS） hybrid materials, using graphene oxide （GO） as precursor and sodium citrate as reductant and stabilizer. The resulting RGONS and Au-RGONS hybrid materials were characterized by UV-vis spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, atomic force microscopy, transmission electron microscopy, and X-ray diffraction. It was found that the RGONS and Au-RGONS hybrid materials formed stable colloidal dispersions through hydrogen bonds between the residual oxygen-containing functionalities on the surface of RGONS and the hydroxyl/carboxyl groups of sodium citrate. The electrochemical responses of RGONS and Au-RGONS hybrid material-modified glassy carbon electrodes （GCE） to three kinds of biomolecules were investigated, and all of them showed a remarkable increase in electrochemical performance relative to a bare GCE.
基金supported by the National Natural Science Foundation of China(21067001)Natural Science Foundation of Guangxi Province(0991083)Innovation Project of Guangxi University for Nationalities(gxun-chx2012091)
文摘Water-soluble gelatin-PbS bionanocomposites （BNCs） were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, UV-vis absorption spectra （UV-vis）, Fourier transform infrared spectra （FT-IR） and circular dichroism （CD）. FT-IR data were used to envis- age the binding of PbS particles with oxygen atoms of carbonyl groups of gelatin molecule. The possible integration mechanism between gelatin and PbS was discussed in detail. The effect of Pb2＋ and PbS on the conformations of gelatin has also been analyzed by means of UV-vis, CD and FT-IR spectra, resulting in less c^-helix content and more open structures （[3-sheet, r-turn, or expanded）. A new formula to calculate the association constant was proposed according to the relationship between the absorbance of gelatin-PbS BNCs and the free concentration of PbS, and apparent association constants K （298/303/308 K： 3.11/2.00/1.60 × 10^6 tool/L） at three different temperatures were calculated based on this formula. Thermodynamic parameters such as AG^θ, △Hθ and △S^θ were also determined. The results of the thermodynamic investigations indicated that the reaction was spontaneous （AG^θ 〈 0）, and enthalpy-driven （△H^8 〈 0）.
基金supported by the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China (Grant No.707015)the University Innovative Research Team Project of Liaoning Province,the National Natural Science Foundation of China (Grant Nos.11204024 and 11004021)the Fundamental Research Funds for the Central Universities (Grant Nos. DC12010208 and DC120101173)
文摘Hydrogenated microcrystalline silicon （mc-Si：H） thin films were deposited by inductively coupled plasma assistant magnetron sputtering （ICP-MS） in an Ar-H2 gas mixture. The role of ion bombardment in the growth of mc-Si：H films was studied with increasing negative bias voltages on the substrate holder from 0 to -100 V. Raman scattering, X-ray diffraction （XRD）, Fourier transform infrared （FTIR） spectroscopy and transmission electron microscopy （TEM） were performed to investigate the microstructure changes of deposited Si films. Raman scattering showed that the high energy ion bombardment resulted in crystalline degradation of Si films. The XRD results showed the decrease and even elimination of preferential growth orientation of crystalline Si films with ion bombardment energy increase. The SiH bonding configuration changes and the increase of bonded hydrogen concentration were determined with the analysis of FTIR spectra. Furthermore, the dramatic evolution of cross-sectional morphology of Si thin films was detected by TEM observation.
