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SYNTHESIS OF MESOPOROUS POLY(STYRENE-co-MALEIC ANHYDRIDE)/SILICA HYBRID MATERIALS VIA A NONSURFACTANT-TEMPLATED SOL-GEL PROCESS 被引量:6
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作者 Jie-bin Pang Kun-yuan Qiu Yen Wei Department of Polymer Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. Department of Chemistry, Drexel University, Philadelphia, Pennsylvania 19104, USA. 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2000年第5期469-472,共4页
Mesoporous poly(styrene-co-maleic anhydride)/silica hybrid materials have been prepared. The synthesis was achieved by the HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and styrene-maleic anhydrid... Mesoporous poly(styrene-co-maleic anhydride)/silica hybrid materials have been prepared. The synthesis was achieved by the HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and styrene-maleic anhydride copolymer in the presence of 3-aminopropyl triethoxysilane (APTES) as a coupling agent and citric acid as a nonsurfactant template or pore-forming agent, followed by ethanol extraction. Characterization results from nitrogen sorption isotherms and powder X-ray diffraction indicate that polymer-modified mesoporous materials with large specific surface areas (e.g. 900 m(2)/g) and pore volumes (e.g. 0.6 cm(3)/g) could be prepared. As the citric acid concentration is increased, the specific surface areas, pore volumes and pore diameters of the hybrid materials increase. 展开更多
关键词 mesoporous hybrid material poly(styrene-co-maleic anhydride)/silica citric acid nonsurfactant template sol-gel process
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Review on Sol-Gel Derived Coatings: Process, Techniques and Optical Applications 被引量:5
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作者 S.M.Attia JueWANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第3期211-218,共8页
Sol-gel process is one of the simplest techniques to manufacture thin films. The quality of the prepared films depends on the parameters of the sol-gel process and the used technique for deposition. A great variety of... Sol-gel process is one of the simplest techniques to manufacture thin films. The quality of the prepared films depends on the parameters of the sol-gel process and the used technique for deposition. A great variety of the sol-gel derived films have been prepared for different applications. We present a review on the sol-gel derived coatings. The description of the process is introduced in details. Different sol-gel deposition techniques are mentioned. The optical applications of the sol-gel derived coatings are reviewed. 展开更多
关键词 sol-gel process COATING Thin film
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Preparation of layered oxide Li(Co_(1/3)Ni_(1/3)Mn_(1/3))O_2 via the sol-gel process 被引量:4
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作者 ZHANG Wen LIU Hanxing HU Chen ZHU Xianjun LI Yanxi 《Rare Metals》 SCIE EI CAS CSCD 2008年第2期158-164,共7页
To obtain homogenous layered oxide Li(Co1/3Ni1/3Mn1/3)O2 as a lithium insertion positive electrode material, the sol-gel process using citric acid as a chelating agent was applied. The material Li(Co1/3Ni1/3Mn1/3)... To obtain homogenous layered oxide Li(Co1/3Ni1/3Mn1/3)O2 as a lithium insertion positive electrode material, the sol-gel process using citric acid as a chelating agent was applied. The material Li(Co1/3Ni1/3Mn1/3)O2 was synthesized at different calcination temperatures. XRD experiment indicated that the layered Li(Co1/3Ni1/3Mn1/3)O2 material could be synthesized at a lower temperature of 800℃, and the oxidation state of Co, Ni, and Mn in the cathode confirmed by XPS were +3, +2, and +4, respectively. SEM observations showed that the synthesized material could form homogenous particle morphology with the particle size of about 200 nm. In spite of different calcination temperatures, the charge-discharge curves of all the samples for the initial cycle were similar, and the cathode synthesized at 900℃ showed a small irreversible capacity loss of 11.24% and a high discharge capacity of 212.2 mAh·g^-1 in the voltage range of 2.9-4.6 V. 展开更多
关键词 lithium-ion battery layered transition metal oxide sol-gel process high capacity
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Synthesis and Characterization of Cerium-Doped Lutetium Aluminum Garnet Phosphors by Nitrate-citrate Sol-Gel Combustion Process 被引量:4
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作者 李会利 刘学建 +1 位作者 张其土 黄莉萍 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第4期401-406,共6页
Nanosized cerium-doped lutetium aluminum garnet (LuAG:Ce) phosphors were prepared by nitrate-citrate solgel combustion process using 1:1 ratio of the citrate:nitrate. The prepared LuAG:Ce phosphors were characte... Nanosized cerium-doped lutetium aluminum garnet (LuAG:Ce) phosphors were prepared by nitrate-citrate solgel combustion process using 1:1 ratio of the citrate:nitrate. The prepared LuAG:Ce phosphors were characterized by XRD, TEM, photoluminescence and radioluminescence spectra excited by UV and X-ray, respectively. The purified crystalline phase of LuAG:Ce was obtained at 900 ℃ by directly crystallizing from amorphous materials. The resultant Lu- AG:Ce phosphors were uniform and had good dispersivity with an average particle size of about 30 urn. Both photoluminescence and radioluminescence were well-known Ce^3+ emissions located in the range of 470 -600 nm consisting of two emission bands because of the transition from the lowest 5d excited state (2D) to the 4f ground state of Ce^3+, which matched well with the sensitivity curve of the Si-photodiode. There was a little red shift for the emission components from the UV-excited emission spectrum to the X-ray-excited emission spectrum. The fast scintillation decay component of 26 ns satisfies the requirements of fast scintillators. 展开更多
关键词 LuAG:Ce phosphors sol-gel combustion process photoluminescence RADIOLUMINESCENCE rare earths
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Methane reforming with CO_2 to syngas over CeO_2-promoted Ni/Al_2O_3-ZrO_2 catalysts prepared via a direct sol-gel process 被引量:2
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作者 Hansheng Li Hang Xu Jinfu Wang 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第1期1-8,共8页
CeO2-promoted Ni/Al2O3-ZrO2 (Ni/Al2O3-ZrO2-CeO2) catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared s... CeO2-promoted Ni/Al2O3-ZrO2 (Ni/Al2O3-ZrO2-CeO2) catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared spectroscopy (IR), thermal gravimetric analysis (TGA), microscopic analysis, X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The catalytic performance for CO2 reforming of methane to synthesis gas was investigated in a continuous-flow micro-reactor under atmospheric pressure. TGA, IR, XRD and microscopic analysis show that the catalysts prepared by the direct sol-gel process consist of Ni particles with a nanostructure of around 5 nm and an amorphous-phase composite oxide support. There exists a chemical interaction between metallic Ni particles and supports, which makes metallic Ni well dispersed, highly active and stable. The addition of CeO2 effectively improves the dispersion and the stability of Ni particles of the prepared catalysts, and enhances the adsorption of CO2 on the surface of catalysts. The catalytic tests for methane reforming with CO2 to synthesis gas show that the Ni/Al2O3-ZrO2-CeO2 catalysts show excellent activity and stability compared with the Ni/Al2O3 catalyst. The excellent catalytic activity and stability of the Ni/Al2O3-ZrO2-CeO2 are attributed to the highly, uniformly and stably dispersed small metallic Ni particles, the high reducibility of the Ni oxides and the interaction between metallic Ni particles and the composite oxide supports. 展开更多
关键词 methane reforming with CO2 SYNGAS Ni-based catalyst CEO2 sol-gel process
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Mechanism of Phase Transformation and Formation of Barium Hexafer rite Doped with Rare-Earths in Sol-Gel Process 被引量:2
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作者 甘树才 洪广言 +2 位作者 张军 车平 唐娟 《Journal of Rare Earths》 SCIE EI CAS CSCD 2003年第1期98-100,共3页
The phase-transformation in sol-gel preparation of barium hexaferrite and the formation of barium hexaferrite doped with La 3+ were studied by chemical p hase analysis, X-ray diffraction and infrared spectrometry an... The phase-transformation in sol-gel preparation of barium hexaferrite and the formation of barium hexaferrite doped with La 3+ were studied by chemical p hase analysis, X-ray diffraction and infrared spectrometry analysis. The expe rimental results show that phase transformation reactions of FeCO 3, Fe 2O 3 and BaFe 2O 4, barium hexaferrite and γ-Fe 2O 3 take place in the heat tr eatment of gel. While the doping lanthanide ion replace barium ion, an equivalen t quantity of Fe 3+ are reduced to Fe 2+ to maintain the charge equili brium. 展开更多
关键词 chemical materials barium hexafettite doped rare earths sol-gel process phase transformation MECHANISM
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Preparation and characterization of BaMgAl_(10)O_(17)∶Eu phosphor coated with MgF_2 by sol-gel process 被引量:2
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作者 李峰 王育华 《中国有色金属学会会刊:英文版》 CSCD 2005年第2期328-331,共4页
In order to prevent BaMgAl10O17∶Eu (BAM) phosphor from thermal degradation, MgF2-coatings on the surface of BAM were prepared by a sol-gel process. The coatings were characterized by X-ray photoelectron spectroscop... In order to prevent BaMgAl10O17∶Eu (BAM) phosphor from thermal degradation, MgF2-coatings on the surface of BAM were prepared by a sol-gel process. The coatings were characterized by X-ray photoelectron spectroscopy and scanning electron microscopy. The results indicate that BAM is successfully coated with homogenous, close MgF2 coatings. The photoluminescence and anti-thermal degradation properties of coated BAM were investigated under 254 and 147 nm excitations. The optimum anti-thermal degradation properties are obtained at the mass ratio of MgF2 to BAM 0.2% under 254 nm excitation and 0.5% under 147 nm excitation, respectively. It is considered that trace MgO formed after baked would cause different optimum coating thicknesses under 254 and 147 nm excitations. 展开更多
关键词 BaMgAl10O17合金 热退化 溶胶-凝胶体 电镀工艺 氟化镁
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Production of HfO_2 thin films using different methods: chemical bath deposition, SILAR and sol–gel process 被引量:1
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作者 Ì.A.Kariper 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2014年第8期832-838,共7页
Hafnium oxide thin films (HOTFs) were successfully deposited onto amorphous glasses using chemical bath deposition, successive ionic layer absorption and reaction (SILAR), and sol-gel methods. The same reactive pr... Hafnium oxide thin films (HOTFs) were successfully deposited onto amorphous glasses using chemical bath deposition, successive ionic layer absorption and reaction (SILAR), and sol-gel methods. The same reactive precursors were used for all of the methods, and all of the films were annealed at 300℃ in an oven (ambient conditions). After this step, the optical and structural properties of the films produced by using the three different methods were compared. The structures of the films were analyzed by X-ray diffTaction (XRD). The optical properties are investigated using the ultraviolet-visible (UV-VIS) spectroscopic technique. The film thickness was measured via atomic force microscopy (AFM) in the tapping mode. The surface properties and elemental ratios of the films were investigated and measured by scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX). The lowest transmittance and the highest reflectance values were observed for the films produced using the SILAR method. In addition, the most intense characteristic XRD peak was observed in the diffraction pattern of the film produced using the SILAR method, and the greatest thickness and average grain size were calculated for the film produced using the SILAR method. The films produced using SILAR method contained fewer cracks than those produced using the other methods. In conclusion, the SILAR method was observed to be the best method for the production of HOTFs. 展开更多
关键词 hafnium oxide thin films optical properties structural properties chemical deposition absorption sol-gel process
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SYNTHESIS AND OPTICAL PROPERTIES OF A NOVEL ORGANIC/INORGANIC HYBRID NONLINEAR OPTICAL POLYMER VIA SOL-GEL PROCESS 被引量:1
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作者 Hong-xia Xi Zhong Li Zhao-xi Liang The Institute of Chemical Engineering South China University Guangzhou 510640 China The Institute of Polymer Science, Zhongshan University Guangzhou 510275, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2001年第4期421-427,共7页
A new organic/inorganic hybrid nonlinear optical (NLO) material was developed by the sol-gel process of an alkoxysilane dye with tetraethoxysilane. A NLO moiety based on 4-nitro-4 ' -hydroxy azobenzene was covalen... A new organic/inorganic hybrid nonlinear optical (NLO) material was developed by the sol-gel process of an alkoxysilane dye with tetraethoxysilane. A NLO moiety based on 4-nitro-4 ' -hydroxy azobenzene was covalently bonded to the triethoxysilane derivative, i.e, gamma -isocyanatopropyl triethoxysilane. The preparation process and properties of the sol-gel derived NLO polymer were studied and characterized by SEM, FTIR,H-1-NMR, UV-Vis, DSC and second harmonic generation (SHG) measurement. The results indicated that the chemical bonding of the chromophores to the inorganic SiO2 networks induces low dipole alignment relaxation and preferable orientational stability. The SHG measurements also showed that the bonded polymer film containing 75 wt% of the akoxysilane dye has a high electro-optic coefficient (r(33)) of 7.1 pm/V at 1.1 mum wavelength, and exhibit good SHG stability, the r(33) values can maintain about 92.7% of its initial value at room temperature for 90 days, and can maintain about 59.3% at 100 degreesC for 300 min. 展开更多
关键词 sol-gel process nonlinear optical material alkoxysilane dye dipole alignment relaxation CHROMOPHORE
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Preparation of Scratch-Resistant Nano-Porous Silica Films Derived by Sol-Gel Process and Their Anti-reflective Properties 被引量:1
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作者 Guangming WU, Jun SHEN, Tianhe YANG, Bin ZHOU and Jue WANGPohl Institute of Solid State Physics, Tongji University, Shanghai 200092, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第4期299-302,共4页
Structural strengthening of the nano porous silica films has been reported. The films were prepared with a base/acid two-step catalyzed TEOS-based sol-gel processing and dip-coating, and then baked in the mixed gas of... Structural strengthening of the nano porous silica films has been reported. The films were prepared with a base/acid two-step catalyzed TEOS-based sol-gel processing and dip-coating, and then baked in the mixed gas of ammonia and water vapor. The silica films were characterized with TEM, AFM, FTIR, spectrophotometer, ellipsometer, and abrasion test, respectively. The experimental results have shown that the films have a nanostructure with a low refractive index and can form an excellent scratch-resistant broadband anti-reflectance. The two-step catalysis noticeably strengthens the films, and the mixed gas treatment further improves mechanical strength of the silica network. Finally the strengthening mechanism has been discussed. 展开更多
关键词 sol-gel process Silica films Anti-reflectance Nano porous structure
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PREPARATION AND SECOND-ORDER OPTICAL NONLINEARITY OF NOVEL PHENOXYSILICON NETWORKS BY SOL-GEL PROCESS 被引量:1
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作者 Xiao Huang Jian Wang Ling-zhi Zhang Zhi-gang Cai Zhao-xi Lianga 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2001年第1期39-44,共6页
Four phenoxysilicon networks for nonlinear optical (NLO) applications were designed and prepared by an extended sol-gel process without additional H2O and catalyst. All poled polymer network films possess high second-... Four phenoxysilicon networks for nonlinear optical (NLO) applications were designed and prepared by an extended sol-gel process without additional H2O and catalyst. All poled polymer network films possess high second-order nonlinear optical coefficients (d(33)) Of 10(-7)similar to 10(-8) esu. The investigation of NLO temporal stability at room temperature and elevated temperature (120 degreesC) indicated that these films exhibit high d(33) stability because the orientation of the chromophores are locked in the phenoxysilicon organic/inorganic networks. 展开更多
关键词 phenoxysilicon networks sol-gel process azobenzene chromophore stilbene chromophore second order optical nonlinearity
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Growth of TiO_2 Nanorods by Sol-gel Template Process 被引量:1
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作者 A.Sadeghzadeh Attar Sh.Mirdamadi +1 位作者 F.Hajiesmaeilbaigi M.Sasani Ghamsari 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2007年第5期611-613,共3页
In this work, TiO2 nanorods with uniform diameter of about 100 nm and a length of several micrometers were successfully prepared by the sol-gel template method. Also the influence of molar ratios of precursor on the m... In this work, TiO2 nanorods with uniform diameter of about 100 nm and a length of several micrometers were successfully prepared by the sol-gel template method. Also the influence of molar ratios of precursor on the morphology and structure of TiO2 nanorods has been investigated. The prepared samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results indicated that the TiO2 nanorods were crystallized in the anatase and rutile phases, after annealing to 400-700℃ up to 2 h. 展开更多
关键词 TiO2 nanorods sol-gel process Template-based growth
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Preparation of LiTi_2(PO_4)_3 by the Sol-gel Method and Investigation of Its Formation Process 被引量:1
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作者 ZHU Jishun Tohge Noboru Minami Tsutomu 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 1999年第2期13-17,共5页
In this study,a novel solgel method has been developed to prepare LiTi2(PO4)3 lithium ion conductor as monophase at relatively low temperature(600).According to the XRD and IR analysis,the asprepared sample remained a... In this study,a novel solgel method has been developed to prepare LiTi2(PO4)3 lithium ion conductor as monophase at relatively low temperature(600).According to the XRD and IR analysis,the asprepared sample remained an amorphous state up to 500.The activation energy was calculated to be 252 kJ/mol according to the modified Kissinger equation. 展开更多
关键词 Lithium ion conductor LiTi2(PO4)3 sol-gel method Crystallization process LiTi2(PO4)3 solgel method Crystallization process
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Preparation of Cd S Microcrystallite Doped Si O_2 Glass Films on Titaniu m-m etal Substrates by Sol- Gel Process
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作者 滕立东 孟华 +2 位作者 王福明 边建华 李文超 《Rare Metals》 SCIE EI CAS CSCD 1999年第3期220-224,共5页
CdS microcrystallite doped SiO 2 glass films on titanium metal substrates were prepared by sol gel process. The effects of solution composition and viscosity, heat treatment parameters and substrate pretreatment m... CdS microcrystallite doped SiO 2 glass films on titanium metal substrates were prepared by sol gel process. The effects of solution composition and viscosity, heat treatment parameters and substrate pretreatment method on the film qualities were studied. The transformation process of gel to CdS doped SiO 2 glass film, the structure of these films, the substrate/film interface bonding state and crystalline phase were analyzed by DTA, IRRS, SEM, EDS and XRD. The IRRS results show that Si O Ti linkages are formed between titanium substrate and thin film during heat treatment process. The preferential heat treatment of titanium surface in oxidizing atmosphere will be beneficial to increase the interface bonding strength. The thin films bonded with the substrates chemically and contained very fine CdS crystals with 20~40 nm in size. 展开更多
关键词 Titanium metal CdS microcrystallite Thin film sol gel process
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Synthesis and Microstructure of Doped Alumina Composite Membrane by Sol-Gel Process
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作者 徐晓虹 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2003年第3期15-19,共5页
The supported membranes of Al 2O 3 and its modification membranes were prepared.Al 2O 3,Al 2O 3 SiO 2 TiO 2 and Al 2O 3 SiO 2 TiO 2 ZrO 2 membranes were mamufatured by the slip casting process using... The supported membranes of Al 2O 3 and its modification membranes were prepared.Al 2O 3,Al 2O 3 SiO 2 TiO 2 and Al 2O 3 SiO 2 TiO 2 ZrO 2 membranes were mamufatured by the slip casting process using mixing boehmite,silicate,titania and zirconia sols under proper conditions,then the composite membrane was prepared.The structure and characteristics of the membrane were determined by XRD,SEM and AFM measurement.The conditions of preparation of the membrane are discussed.The thickness of the layer is about 1-2μm,the diameter of an average pore is 200-300nm and has a narrow pore distribution without crack forming.By changing the ratios of Al∶Si∶Ti∶Zr(mol),variations of surface pore size of Al 2O 3 SiO 2 TiO 2 ZrO 2 membrane can be gained. 展开更多
关键词 DOPED alumina composite membrane sol gel process
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Hydroxyapatite/alumina nanocrystalline composite powders synthesized by sol–gel process for biomedical applications
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作者 S.Khors M.H.Fathi +1 位作者 S.Salehi S.Amirkhanlou 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2014年第10期1033-1036,共4页
Hydroxyapatite/alumina nanocrystalline composite powders needed for various biomedical applications were successfully synthe- sized by sol-gel process. Structural and morphological investigations of the prepared compo... Hydroxyapatite/alumina nanocrystalline composite powders needed for various biomedical applications were successfully synthe- sized by sol-gel process. Structural and morphological investigations of the prepared composite powders were performed using X-ray dif- fractometer (XRD), scanning electron microscopy (SEM), X'Pert HighScore software, and Clemex Vision image analysis software. The re- suits show that the crystallite size of the obtained composite powders is in the range of 25 to 90 nm. SEM evaluation shows that the obtained composite powders have a porous structure, which is very useful for biomedical applications. The spherical nanoparticles in the range of 60 to 800 nm are embedded in the agglomerated clusters of the prepared composite powders. 展开更多
关键词 nanocrystalline materials BIOMATERIALS HYDROXYAPATITE ALUMINA sol-gel process nanostructures
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Agglomerate control in the complexing sol-gel process
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作者 尹邦跃 王零森 +1 位作者 樊毅 张金生 《中国有色金属学会会刊:英文版》 EI CSCD 1999年第4期712-716,共5页
Nanometer ZrO2 - 8% Y2O3 (mole fraction, % ) powders were prepared by the EDTA (ethylenediaminetetraacetic acid) sol-gel process. Effects of the addition of ethylene glycol on agglomerate control was investigated. The... Nanometer ZrO2 - 8% Y2O3 (mole fraction, % ) powders were prepared by the EDTA (ethylenediaminetetraacetic acid) sol-gel process. Effects of the addition of ethylene glycol on agglomerate control was investigated. The results showed that because of the replacement of hydrogen bonds with ethylene glycol in the polymerized gel, gel stabilization and homogeneity were improved and close approach of gel particles was prevented, which led to reduction of hard agglomerates to some extent. Calcined at 4OO t for 2 h and 700 C for 2 h, the powders had a specific surface area of 35 m2/g, average particle size of 28 nm, and median particle size (d50) of 0. 44um with very sharp distribution, mostly being soft agglomerates. 展开更多
关键词 COMPLEXING EDTA sol-gel process ZrO2 (Y2O3) AGGLOMERATION
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RHEOLOGICAL MODIFICATION OF EPOXY RESINS WITH NANO SILICA PREPARED BY THE SOL-GEL PROCESS
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作者 Xia Wang Jiang Li +1 位作者 Cheng-fen Long Yun-zhao Yu PCLCC Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China PCLCC is the Polymer Chemistry Laboratory, Chinese Academy of Sciences and China Petro-Chemica Corporation 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1999年第3期253-257,共5页
Nano silica-modified epoxy resins were synthesized by the sol-gel process, The materials have the morphological structure of nano particales dispersed in the epoxy matrix. The dispersed phase formed a physical network... Nano silica-modified epoxy resins were synthesized by the sol-gel process, The materials have the morphological structure of nano particales dispersed in the epoxy matrix. The dispersed phase formed a physical network in the resin and thus influenced the rheological behavior greatly. However, the nano silica did not show a significant influence on the mechanical properties of the cured resins. 展开更多
关键词 epoxy resin nano silica mechanical properties RHEOLOGY sol-gel process
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Facile and Controlled Synthesis of Silica Sol Nanospheres Through a Modifi ed Sol-Gel Process
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作者 李洁 陈连喜 +1 位作者 ZHANG Zhongming JIAO Caibin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第3期478-482,共5页
An effective and reproducible preparation of silica sol nanospheres via a modified sol-gel process has been described. Monodisperse and stable silica sol nanospheres with uniformsize were successfully obtained through... An effective and reproducible preparation of silica sol nanospheres via a modified sol-gel process has been described. Monodisperse and stable silica sol nanospheres with uniformsize were successfully obtained through the optimized synthesis in which the mixture of tetraethyl orthosilicate (TEOS) and ethanol was followed by the addition of water and ammonium hydroxide (NH3) separately, and the size of silica sol spheres was strictly controlled in the range of 25-119 nm with a narrow size distribution by fine adjustment of several reaction parameters. Results showed that in the presence of low concentration of TEOS, spheres size rose first and reached maximum when H2O concentration was up to 66 g/L. However, the diameter of silica sol spheres decreased above 66 g/L of H2O concentration. Furthermore, it was also found that the size and size distribution of silica sol nanospheres were affected by NH3 concentration. As NH3 concentration increased from 15 to 35 g/L, the diameter declined from 83 to 64 nm. Nevertheless, higher NH3 concentration would result in relatively broad size distribution, and gelation occurred when NH3 concentration reached 44 g/L. In addition, the effect of the different feed rates ofNH3 on the size growth of silica sol nanospheres was also discussed. 展开更多
关键词 sol-gel process optimized synthesis silica sol NANOSPHERES
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Synthesis of Anatase TiO_2 Nanoparticles by Improved Sol-Gel Process at Low Temperature
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作者 王玉玲 杜海燕 +1 位作者 韩晶 崔兰 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第S1期306-308,共3页
The nanocrystalline TiO_2 powder were prepared by improved sol-gel method at low temperature under ambient pressure. The prepared TiO_2 powder was characterized by X-ray diffraction (XRD), transmission electron micros... The nanocrystalline TiO_2 powder were prepared by improved sol-gel method at low temperature under ambient pressure. The prepared TiO_2 powder was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM). It is found that the yield of anatase TiO_2 significantly increases with the reduction of pH by increasing the nucleation rate of anatase. There is an optimum amount of water in sol for the formation of anatase by combining two effects on the concentration of Ti(OH)_4 in gels. Increasing in reaction temperature also benefit to the nucleation of anatase of TiO_2. 展开更多
关键词 improved sol-gel process titanium dioxide NANOCRYSTALLINE low temperature
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