期刊文献+
共找到569篇文章
< 1 2 29 >
每页显示 20 50 100
Synthesis and Characterization of Nanocrystalline SrAl_2O_4∶Eu, Dy Long Afterglow Phosphors by Sol-Gel Method 被引量:4
1
作者 张平 徐明霞 +1 位作者 沈毅 田玉明 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第S1期26-29,共4页
Eu 2+, Dy 3+ co-doped nanocrystalline strontium aluminate phosphor powders with brightness and long afterglow were synthesized by the sol-gel method at 1200 ℃ for 2 h. The samples were characterized by X-ray diffract... Eu 2+, Dy 3+ co-doped nanocrystalline strontium aluminate phosphor powders with brightness and long afterglow were synthesized by the sol-gel method at 1200 ℃ for 2 h. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results of XRD show that the single crystalline phase is α-SrAl_2O_4. According to the observation of SEM, the particles of the samples are needle-like. Compared with the samples synthesized by solid state reaction, the grain size of the sol-gel method is to nanometer grade. A clear blue shift occurs in the excitation and emission spectra. The blue shift in nanocrystalline SrAl_2O_4∶Eu, Dy phosphor can be attributed to the quantum-size-effect of the luminescent particles. 展开更多
关键词 nanocrystlline strontium aluminate sol-gel method long afterglow luminescent properties rare earths
下载PDF
Synthesis and Characterization of Er^(3+)∶Y_(3)Al_(5)O_(12) Nanocrystalline Powders Prepared by Sol-Gel Method
2
作者 Li Zhanfa Yuan Duorong +3 位作者 Duan Xiulan Shi Xuzhong Song Jian'an Wang Lihua 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第z1期125-127,共3页
Nano-sized Er^(3+)∶Y_(3)Al_(5)O_(12)powders was successfully prepared via a simple sol-gel route at as low a temperature at 800℃whereas a temperature much higher is necessary to obtain this compound by solid state s... Nano-sized Er^(3+)∶Y_(3)Al_(5)O_(12)powders was successfully prepared via a simple sol-gel route at as low a temperature at 800℃whereas a temperature much higher is necessary to obtain this compound by solid state synthesis(about 1500℃).The phase purity,composition and microstructural features of the materials were analyzed by means of X-ray diffraction(XRD),infrared spectroscopy(IR)and transmission electron microscopy(TEM),and no other intermediate phase were observed to form in the range of 700~1000℃.The luminescence spectra of Er^(3+)substituted for Y^(3+)in YAG in 1%content was characterized on samples at different temperature. 展开更多
关键词 PREPARATION YAG nanocrystalline powders sol-gel method
下载PDF
Comparative structural and electrochemical properties of mixed P2/O′3-layered sodium nickel manganese oxide prepared by sol-gel and electrospinning methods:Effect of Na-excess content 被引量:1
3
作者 Thongsuk Sichumsaeng Atchara Chinnakorn +3 位作者 Ornuma Kalawa Jintara Padchasri Pinit Kidkhunthod Santi Maensiri 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第10期1887-1896,共10页
The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X... The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors. 展开更多
关键词 sodium nickel manganese oxide mixed P2/O′3-type Na-excess content sol-gel method electrospinning method electrochemical properties
下载PDF
Investigation on mechanism of magnetization reversal for nanocrystalline Pr-Fe-B permanent magnets by micromagnetic finite element methods 被引量:4
4
作者 郑波 赵素芬 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第1期145-149,共5页
Magnetization configurations were calculated under various magnetic fields for nanocrystalline Pr-Fe-B permanent magnets by micromagnetic finite element method.According to the configurations during demagnetization pr... Magnetization configurations were calculated under various magnetic fields for nanocrystalline Pr-Fe-B permanent magnets by micromagnetic finite element method.According to the configurations during demagnetization process, the mechanism of magnetization reversal was analyzed.For the Pr2Fe14B with 10 nm grains or its composite with 10vol.% α-Fe, the coercivity was determined by nucleation of reversed domain that took place at grain boundaries.However, for Pr2Fe14B with 30 nm grains, coercivity was controlled by pinning of the nucle-ated domain.For Pr2Fe14B/α-Fe with 30vol.% α-Fe, the demagnetization behavior was characterized by continuous reversal of α-Fe moment. 展开更多
关键词 nanocrystalline permanent magnets COERCIVITY MICROMAGNETICS finite element method rare earths
下载PDF
Microstructure and magnetic characteristics of nanocrystalline Ni0.5Zn0.5 ferrite synthesized by a spraying-coprecipitation method 被引量:2
5
作者 刘银 丘泰 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第12期3837-3842,共6页
Nanocrystalline Ni0.5Zn0.5 ferrite with average grain sizes ranging from 10 to 100 nm is prepared by using a spraying-coprecipitation method. The results indicate that the nanocrystalline Ni0.5Zn0.5 ferrite is ferroma... Nanocrystalline Ni0.5Zn0.5 ferrite with average grain sizes ranging from 10 to 100 nm is prepared by using a spraying-coprecipitation method. The results indicate that the nanocrystalline Ni0.5Zn0.5 ferrite is ferromagnetic without the superparamagnetic phenomenon observed at room temperature. Specific saturation magnetization of nanocrystalline Nio.sZno.5 ferrite increases from 40.2 to 75.6 emu/g as grain size increases from 11 to 94nm. Coercivity of nanocrystalline Ni0.5Zn0.5 ferrite increases monotonically when d 〈 62 nm.The relationship between the coercivity and the mean grain size is well fitted into a relation Hc - d^3. A theoretically evaluated value of the critical grain size is 141nm larger than the experimental value 62nm for nanocrystalline Ni0.5Zn0.5 ferrite. The magnetic behaviour of nanocrystalline Ni0.5Zn0.5 ferrite may be explained by using the random anisotropy theory. 展开更多
关键词 nanocrystalline material Ni0.5Zn0.5 ferrite spraying-coprecipitation method
下载PDF
Effect of Zn^(2+) Content on the Microstructure and Magnetic Properties of Nanocrystalline Ni_(1-x)Zn_xFe_2O_4 Ferrite by a Spraying-coprecipitation Method 被引量:1
6
作者 刘银 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第3期429-431,共3页
Nanocrystalline Ni1-xZnxFe2O4 ferrites with 0≤x≤1 were successfully prepared by a spraying-coprecipitation method.The microstructure was investigated by using XRD and TEM.Magnetic properties were measured with vibra... Nanocrystalline Ni1-xZnxFe2O4 ferrites with 0≤x≤1 were successfully prepared by a spraying-coprecipitation method.The microstructure was investigated by using XRD and TEM.Magnetic properties were measured with vibrating sample magnetometer(VSM) at room temperature.The results show that the grain size of nanocrystalline Ni1-xZnxFe2O4 ferrite calcined at 600 ℃ for 1.5 h is about 30 nm.Lattice parameter and specific saturation magnetization Ms of nanocrystalline Ni1-xZnxFe2O4 ferrite increase with the Zn^2+ ions content at room temperature,and maximum Ms is 66.8 A·m^2·kg^-1 as the Zn^2+ ions content is around 0.5,and coercivity Hc of the nanocrystalline Ni1-xZnxFe2O4 ferrite decreases with Zn^2+ ions content. 展开更多
关键词 nanocrystalline material Ni-Zn ferrite spraying-coprecipitation method magnetic properties MICROSTRUCTURE
下载PDF
Sol-gel synthesis of nanometer silicon/silicon suboxide/carbon anode material
7
作者 QIN Tong WANG Zheng LI Zhengzheng 《Baosteel Technical Research》 CAS 2024年第2期12-18,共7页
A stacked Si/SiO_(x)/C composite anode material with carbon-coated structure was prepared by sol-gel method combined with carbothermal reduction using organic silicon.The results of X-ray diffractometry, scanning elec... A stacked Si/SiO_(x)/C composite anode material with carbon-coated structure was prepared by sol-gel method combined with carbothermal reduction using organic silicon.The results of X-ray diffractometry, scanning electron microscopy, and elemental analysis show that the Si/SiO_(x)/C material is a secondary particle with a porous micronanostructure, and the presence of nanometer silicon does not affect the carbothermal reduction and carbon coating.Electrochemical test results indicate that the specific capacity and first coulombic efficiency of SiO_(x)/C composite with nanometer silicon can be increased to 1 946.05 mAh/g and 76.49%,respectively.The reversible specific capacity of Si/SiO_(x)/C material blended with graphite is 749.69 mAh/g after 100 cycles at a current density of 0.1 C,and the capacity retention rate is up to 89.03%.Therefore, the composite has excellent electrochemical cycle stability. 展开更多
关键词 sol-gel method nanometer silicon silicon suboxide anode material
下载PDF
Influence of two-step cooling method on magnetic properties of Fe_(82)Mo_7B_(10)Cu_1 nanocrystalline alloy 被引量:1
8
作者 彭坤 周灵平 +2 位作者 胡爱平 朱家俊 李德意 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第4期852-856,共5页
Soft magnetic properties of Fe82Mo7B10Cu1 nanocrystalline alloy were studied as a function of cooling condition. The results show that higher permeability and relaxation frequency can be obtained by the two-step cooli... Soft magnetic properties of Fe82Mo7B10Cu1 nanocrystalline alloy were studied as a function of cooling condition. The results show that higher permeability and relaxation frequency can be obtained by the two-step cooling method, and the pinning field of the sample obtained by this method is smaller than that of the furnace-cooled and water-quenched samples. This phenomenon was interpreted in terms of internal stress and the magnetic ordering of the residual amorphous phase. The two-step cooling treatment is an effective way to improve the soft magnetic properties of Fe82Mo7B10Cu1 nanocrystalline alloy. 展开更多
关键词 纳米晶合金 两步冷却法 磁性 铁钼硼铜合金
下载PDF
New Numerical Method to Calculate the True Optical Absorption of Hydrogenated Nanocrystalline Silicon Thin Films
9
作者 Fatiha Besahraoui Larbi Chahed +1 位作者 Yahia Bouizem Jamal Dine Sib 《World Journal of Nano Science and Engineering》 2012年第1期1-5,共5页
The enhanced optical absorption measured by Constant Photocurrent Method (CPM) of hydrogenated nanocrystalline silicon thin films is due mainly to bulk and/or surface light scattering effects. A new numerical method i... The enhanced optical absorption measured by Constant Photocurrent Method (CPM) of hydrogenated nanocrystalline silicon thin films is due mainly to bulk and/or surface light scattering effects. A new numerical method is presented to calculate both true optical absorption and scattering coefficient from CPM absorption spectra of nanotextured nano-crystalline silicon films. Bulk and surface light scattering contributions can be unified through the correlation obtained between the scattering coefficient and surface roughness obtained using our method. 展开更多
关键词 Solution Hydrogenated nanocrystalline Silicon Constant PHOTOCURRENT method Optical Absorption Bulk Light Scattering Surface ROUGHNESS Film Thickness
下载PDF
Synthesis and electrochemical properties of highly dispersed Li_(4)Ti_(5)O_(12)nanocrystalline for lithium secondary batteries 被引量:4
10
作者 王瑾 刘晓敏 杨晖 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第3期613-620,共8页
A sol-gel method using lauric acid as surfactant was used to synthesize Li4Ti5O12 nanocrystals with an ultra-fine particle size distribution between 120 and 250 nm.In order to obtain the electrode materials with the b... A sol-gel method using lauric acid as surfactant was used to synthesize Li4Ti5O12 nanocrystals with an ultra-fine particle size distribution between 120 and 250 nm.In order to obtain the electrode materials with the best electrochemical performance,the content of lauric acid during Li4Ti5O12 synthesis was systematically studied.The physical and electrochemical properties of the synthesized samples were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),laser particle size analysis,alternating current impedance(AC) and galvanostatic charge-discharge experiments.The highly dispersed Li4Ti5O12 nanocrystals obtained at 800 ℃ for 10 h can deliver a specific capacity of 163.3 mA-h/g at 1C rate without obvious capacity fade up to 50 cycles.The results suggest that well dispersed Li4Ti5O12 nanocrystals shorten the Li-ion diffusion length and enhance the electrochemical kinetics of the samples,which are very crucial to high rate capability. 展开更多
关键词 lithium-ion battery lithium titanate NANOCRYSTALS SURFACTANT sol-gel method
下载PDF
Preparation of long alumina fibers by sol-gel method using malic acid 被引量:10
11
作者 谭宏斌 郭从盛 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第7期1563-1567,共5页
The precursor sol of alumina was prepared by sol-gel method with aluminum nitrate and malic acid as raw materials.The effects of content of malic acid and polyvinylpyrrolidone (PVP) on sol spinnability were explored... The precursor sol of alumina was prepared by sol-gel method with aluminum nitrate and malic acid as raw materials.The effects of content of malic acid and polyvinylpyrrolidone (PVP) on sol spinnability were explored.The gel fibers with above 80 cm in length were obtained by mixing aluminum nitrate,malic acid and PVP on mass ratio of 10 3 1.5.Thermogravimetry-differential scanning calorimetry (TG-DSC),Fourier transform infrared (FTIR) spectrum,X-ray diffractometry (XRD),and scanning electron microscopy (SEM) were used to characterize the properties of the gel and ceramic fibers.The alumina fibers with a smooth surface and about 20μm in diameter were obtained by sintering at 1 200℃,and their main phase was indentified to be α-Al2O3. 展开更多
关键词 AL2O3 long fiber sol-gel method POLYVINYLPYRROLIDONE
下载PDF
A Novel Approach to Synthesizing Porous ZnO Films: Inorganic Chelating Sol-Gel Method 被引量:1
12
作者 杨立荣 靳正国 +1 位作者 步邵静 程志捷 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第3期241-246,共6页
Porous ZnO films are synthesized by inorganic chelating sol-gel method,which is a novel sol-gel technique using zinc nitrate as starting materials and citric acid as the chelating reagent.The crystal structure,surface... Porous ZnO films are synthesized by inorganic chelating sol-gel method,which is a novel sol-gel technique using zinc nitrate as starting materials and citric acid as the chelating reagent.The crystal structure,surface morphology,porous and optical properties of the deposited films are investigated.X-ray diffraction pattern analysis shows that crystal structure of the ZnO films is hexagonal wurtzite.Scanning electron microscopy (SEM) shows that the ZnO film is porous.The curve of pore size distribution has two peak values at about 2.02nm and 4.97nm and BET surface area of the ZnO film is 27.57m2/g.In addition,the transmittance spectrum gives a high transmittance of 85% in the visible region and optical bandgap of the ZnO film (fired at 500℃) is 3.25eV. 展开更多
关键词 porous ZnO film inorganic chelating sol-gel method pore size distribution PROPERTIES
下载PDF
Synthesis of LiMnPO_4/C composite material for lithium ion batteries by sol-gel method
13
作者 钟胜奎 王友 +1 位作者 刘洁群 王健 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第10期2535-2540,共6页
The LiMnPO4/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical performance tests were adopted to... The LiMnPO4/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical performance tests were adopted to characterize the properties of LiMnPO4/C. The XRD studies show that the pure olivine phase LiMnPO4 can be obtained at a low temperature of 500 °C. The SEM analyses illustrate that the citric acid used as the chelating reagent and carbon source can restrain the particle size of LiMnPO4/C well. The LiMnPO4/C sample synthesized at 500 °C for 10 h performs the highest initial discharge capacity of 122.6 mA-h/g, retaining 112.4 mA-h/g over 30 cycles at 0.05C rate. The citric acid based sol-gel method is favor to obtain the high electrochemical performance of LiMnPO4/C. 展开更多
关键词 lithium-ion battery cathode material sol-gel method LiMnPO4/C electrochemical performance
下载PDF
Photocatalytic Activity of Nanosized ZnWO_4 Prepared by the Sol-gel Method 被引量:11
14
作者 WU Yan ZHANG Shi-cheng ZHANG Li-wu ZHU Yong-fa 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2007年第4期465-468,共4页
Nanosized ZnWO4 photocatalysts were successfully synthesized via the sol-gel process in a temperature range of 450-800℃. The grain size, crystal size, and crystallinity of ZnWO4 particles increased with the increase ... Nanosized ZnWO4 photocatalysts were successfully synthesized via the sol-gel process in a temperature range of 450-800℃. The grain size, crystal size, and crystallinity of ZnWO4 particles increased with the increase of calcina- tion temperature and prolonging calcination time. The photocatalytic activity was measured for the degradation of an aqueous Rhodamine-B(RhB) solution and gaseous formaldehyde(FAD). With the increase of calcination temperature and time, the activities increased to a maximum and then decreased. ZnWO4 photocatalyst prepared at 550℃ for I0 h showed the highest activity, which is similar to the photocatalytic activity of P25TiO2 for the degradation of gase-ous FAD. High crystallinity, large surface area, and good dispersion are responsible for the high photocatalytic per- formance of the prepared ZnWO4. 展开更多
关键词 NANOSIZED sol-gel method PHOTOCATALYST ZnWO4
下载PDF
Direct Synthesis of Diphenyl Carbonate with Heterogeneous Catalyst and Optimal Synthesis Conditions of the Support Prepared by Sol-gel Method 被引量:10
15
作者 郭红霞 陈红萍 +3 位作者 梁英华 芮玉兰 吕敬德 付占达 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第2期223-227,共5页
The support of catalyst for the direct synthesis of diphenyl carbonate (DPC) by heterogeneous catalytic reaction was prepared by the sol-gel method. Compared with activated charcoal, molecular sieve, porous ceramics... The support of catalyst for the direct synthesis of diphenyl carbonate (DPC) by heterogeneous catalytic reaction was prepared by the sol-gel method. Compared with activated charcoal, molecular sieve, porous ceramics, hopcalite, the support prepared by the sol-gel method has higher activity. The characterization of the support by X-ray diffraction (XRD) and transmission electron microscope (TEM) show that the mare crystal phase is Co2MnO4 and the average particle diameter is about 40 nm. The optimum conditions for synthesis of the support were determined by orthogonal experiments, which indicate that the proportion of Cu, Mn, and Co is the first important factor influencing the yield and selectivity of DPC. Temperature of calcination is the second one. The optimum conditions are: molar proportion of Cu, Mn, and Co being 1 : 1 : 1, temperature of calcination 700℃, drying at 100~C, temperature of water bath 85~C. The yield and selectivity of DPC in the process can reach 38% and 99% in the batch operation, respectively. The copper cobalt manganese mixed oxides chosen as the support contribute more to the high catalytic activity than the sol-gel method. 展开更多
关键词 diphenyl carbonate heterogeneous catalyst sol-gel method optimum condition
下载PDF
Preparation and properties of nanocrystal SmBO_3 by nitrate-citrate sol-gel combustion method 被引量:8
16
作者 何伟 张晶 +1 位作者 王丽熙 张其土 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第2期231-233,共3页
Nanocrystal SmBO3 powders were synthesized by nitrate-citrate sol-gel combustion method. The phase evolution, morphologies and absorbency of the synthesized powders were characterized by X-ray diffraction (XRD), Fie... Nanocrystal SmBO3 powders were synthesized by nitrate-citrate sol-gel combustion method. The phase evolution, morphologies and absorbency of the synthesized powders were characterized by X-ray diffraction (XRD), Field emission scanning electronic microscope (FESEM), Fourier transform infrared spectroscopy (FFIR) and UV-3101PC spectrophotometer (UVPC), respectively. XRD and FESEM results showed that pure SmBO3 phase was obtained at 750 ℃, with an average original particle size of about 100 nm. FTIR showed that there were apparently concentrated absorbent peaks between 500 and 1400 cm^-1. Moreover, the reflectivity of the powders apparently decreased at the wavelength between 1.05 and 1.15 μm. Therefore, SmBO3 might be a kind of absorbent material for infrared laser. 展开更多
关键词 SMBO3 sol-gel combustion method optical absorption rare earths
下载PDF
Preparation and Characterization of Sodium Sulfate/Silica Composite as a Shape-stabilized Phase Change Material by Sol-gel Method 被引量:7
17
作者 郭强 王涛 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第3期360-364,共5页
A sodium sulfate (NaeSO4)/silica (SiO2) composite was prepared as a shape-stabilized solid-liquid phase change material by a sol-gel procedure using Na2SiO3 as the silica source. Na2SO4 in the composite acts as a ... A sodium sulfate (NaeSO4)/silica (SiO2) composite was prepared as a shape-stabilized solid-liquid phase change material by a sol-gel procedure using Na2SiO3 as the silica source. Na2SO4 in the composite acts as a latent heat storage substance for solid-liquid phase change, while SiO2 acts as a support material to provide structural strength and prevent leakage of melted NazSO4. The microstructure and composition of the prepared composite were characterized by the N2 adsorption, transmission electron microscope (TEM), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction. The results show that the prepared Na2SOJSiO2 composite is a nanostructured hybrid of NazSO4 and SiO2 without new substances produced during the phase change. The macroscopic shape of the NazSO4/SiO2 composite after the melting and freezing cycles does not change and there is no leakage of Na2SO4. Determined by differential scanning calorimeter (DSC) analysis, the values of phase change latent heat of melting and freezing of the prepared NazSO4/SiO2 (50%, by mass) composite are 82.3 kJ.kg i and 83.7 kJ.kg-1, and temperatures of melting and freezing are 886.0 ℃ and 880.6 ℃, respectively. Furthermore, the Na2SOJSiO2 composite maintains good thermal energy storage and release ability even after 100 cycles of melting and freezing. The satisfactory thermal storage performance renders this composite a versatile tool for high-temperature thermal energy storage. 展开更多
关键词 sodium sulfate silicon dioxide phase change material shape-stabilized sol-gel method
下载PDF
Grain Size and Photocatalytic Activity of Nanometer TiO_2 Thin Films Prepared by the Sol-gel Method 被引量:8
18
作者 余家国 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2001年第2期1-5,共5页
Transparent anatase TiO2 nanometer thin films with photocatalytic activity were prepared via the sol-gel method on soda-lime glass. The thickness , crystalline phase, grain size, surface hydroxyl amount and so on were... Transparent anatase TiO2 nanometer thin films with photocatalytic activity were prepared via the sol-gel method on soda-lime glass. The thickness , crystalline phase, grain size, surface hydroxyl amount and so on were characterized by scanning electron microscopy (SEM) , X-ray diffraction (XRD), transmission electron microscopy ( TEM), X-ray photoelectron spectroscopy (XPS) and UV-visible spectrophotometer ( UV-VIS). The photocatalytic activity of TiO2 thin films was evaluated for the photocatalytic decolorization of aqueous methyl orange . The effects of film thickness on the crystalline phase, grain size, transmittance and photocatalytic activity of nanometer Ti02 thin films were discussed. 展开更多
关键词 sol-gel method titania thin films grain size photocatalytic activity
下载PDF
Luminescence properties of red-emitting Ca_2Al_2SiO_7:Eu^(3+) nanoparticles prepared by sol-gel method 被引量:4
19
作者 CAI Jinjun PAN Huanhuan WANG Yi 《Rare Metals》 SCIE EI CAS CSCD 2011年第4期374-380,共7页
A series of red-emitting Ca2_xA12SiOT:xEu^3+ (x = 1 mol.%-10 tool.%) phosphors were synthesized by the sol-gel method. The effects of annealing temperature and doping concentration on the crystal structure and lum... A series of red-emitting Ca2_xA12SiOT:xEu^3+ (x = 1 mol.%-10 tool.%) phosphors were synthesized by the sol-gel method. The effects of annealing temperature and doping concentration on the crystal structure and luminescence properties of Ca2A12SiO7:Eu^3+ phosphors were investigated. X-ray diffraction (XRD) profiles showed that all peaks could be attributed to the tetragonal Ca2A12SiO7 phase when the sample was annealed at 1000℃. Scanning electron microscopy (SEM) micrographs indicate that the phosphors have an irregularly rounded mor- phology with particles of about 200 nm. Excitation spectra showed that the strong broad band at around 258 nm and weak sharp lines in 350-490 nm were attributed to the charge transfer band of Eu^3+-O^2- and f-f transitions within the 4f^6 configuration of Eu^3+ ions, respectively. Emission spectra implied that the red luminescence could be attributed to the transitions from the ^5D0 excited level to the 7Fj (J = 0, 1, 2, 3, 4) levels of Eu3+ions with the main electric dipole transition ^5D0→^7F2 (618 and 620 nm), and Eu^3+ ions prefer to occupy a lower symmetry site in the crystal lattice. Moreover, the photoluminescence (PL) intensity was strongly dependent on both the sintering temperature and doping concentration, and the highest PL intensity was observed at an Eu^3+ concentration x = 7 mol.% after annealing at ll00℃. The obtained Ca2A12SiO7:Eu^+3+ phosphor may have potential application for the red lamp phosphor. 展开更多
关键词 optical materials red phosphor sol-gel method PHOTOLUMINESCENCE SILICATES
下载PDF
Effects of sol-gel method and lanthanum addition on catalytic performances of nickel-based catalysts for methane reforming with carbon dioxide 被引量:4
20
作者 黎先财 胡全红 +2 位作者 杨沂凤 陈娟荣 赖志华 《Journal of Rare Earths》 SCIE EI CAS CSCD 2008年第6期864-868,共5页
The nickel-based catalysts were prepared by the sol-gel method and used for the CH4 reforming with CO2. The effects of the sol-gel method on the specific surface area, catalytic activity, desorption, and reduction per... The nickel-based catalysts were prepared by the sol-gel method and used for the CH4 reforming with CO2. The effects of the sol-gel method on the specific surface area, catalytic activity, desorption, and reduction performances of catalysts were investigated with BET, TPR, and TPD. Compared with the catalyst prepared by the impregnation method, the results indicated that the catalysts prepared by the sol-gel method had larger specific surface area, showing higher catalytic activities and exhibiting perfect desorption and reduction performances. In addition, the modification effects of adding La were studied, and it was found that the 0.75NLBT catalyst constituted of 5wt.%Ni-0.75wt.%La was optimal. 展开更多
关键词 sol-gel method nickel-based catalyst REFORMING catalytic performance rare earths
下载PDF
上一页 1 2 29 下一页 到第
使用帮助 返回顶部