Single-phase homogeneous Ce1-x ZrxO2 solid versed microemulsion method. The structural properties solutions with various compositions were synthesized using the reand performance of Ce1- xZrxO2 were studied using XRD,...Single-phase homogeneous Ce1-x ZrxO2 solid versed microemulsion method. The structural properties solutions with various compositions were synthesized using the reand performance of Ce1- xZrxO2 were studied using XRD, BET, SEM, HRTEM, TPR and CO oxidation measurements. The results show that in the range of x = 0.4 - 0.5 and x = 0.6 - 1.0, the solid solutions posses the cubic and the tetragonal phase structure, respectively, Solids obtained by the reversed microemulsion method were more homogeneous on the whole range of composition, XRD investigations of the prepared materials did not show segregation of cerium or zirconium oxides, Highly uniform nanosize solid solution particles of ceria-zirconia with high specific area （146.7 m^2·g^-1） were attained under the conditions of this study. The TPR results and CO oxidation measurements indicate that the performance of the CeO2-ZrO2 mixed oxides is strongly related to the composition and structure of the oxides. Enhancement of the activity was found for the catalyst prepared by reversed microemulsion method as compared to the sample prepared by sol-gel method.展开更多
A novel method to prepare mesoporous nano-zirconia was developed. Thesynthesis was carried out in the presence of PEO surfactants via a solid-state reaction. Thematerials exhibit a strong diffraction peak at low 2θ a...A novel method to prepare mesoporous nano-zirconia was developed. Thesynthesis was carried out in the presence of PEO surfactants via a solid-state reaction. Thematerials exhibit a strong diffraction peak at low 2θ angle and their nitrogenadsorption/desorption isotherms are typical of type IV with H1 hysteresis loops. The pore structureimaged by TEM can be described as wormhole domains. The tetragonal zirconia nanocrystals are uniformin size (around 1.5 nm) and their mesopores focus on around 4.6 nm. The zirconia nanocrystal growthis tentatively postulated to be the result of an aggregation mechanism. This study also revealsthat the PEO surfactants can interact with the Zr-O-Zr framework to reinforce the thermal stabilityof zirconia. The ratio of NaOH to ZrOCl_2, crystallization and calcination temperature play animportant role in the synthesis of mesoporous nano-zirconia.展开更多
The introduction of mesoporous nanosize zirconia to the catalyst for methanol synthesis dedicates the nanosized catalyst and mesoporous duplicated properties. The catalyst bears the larger surface area, larger mesopor...The introduction of mesoporous nanosize zirconia to the catalyst for methanol synthesis dedicates the nanosized catalyst and mesoporous duplicated properties. The catalyst bears the larger surface area, larger mesoporous volume and more uniform diameter, more surface metal atoms and oxygen vacancies than the catalyst prepared with the conventional coprecipitation method. The modification of microstructure and electronic effect could result in the change of the reduced chemical state and decrease of reducuction temperature of copper, donating the higher activity and methanol selectivity to the catalyst. The results of methanol synthesis demonstrate that the Cu^＋ is the optimum active site. Also, the interaction between the copper and zirconia shows the synergistic effect to fulfil the methanol synthesis.展开更多
Functional phthalocyanine （Pc） compounds of H2Pc, TiOPc, FePc and CIAIPc were synthesized with a yield of 46.7%, 91.2%, 37.4% and 34.0%, respectively. Nanosized TiOPc was synthesized via a one-step sol-gel method an...Functional phthalocyanine （Pc） compounds of H2Pc, TiOPc, FePc and CIAIPc were synthesized with a yield of 46.7%, 91.2%, 37.4% and 34.0%, respectively. Nanosized TiOPc was synthesized via a one-step sol-gel method and effects of surfactant doses, nucleation temperature on TiOPc particle size and photoconductivity were investigated. When re（PEG）： m（TiOPc） was 0.1 and nucleation temperature was 0℃, the as-obtained TiOPc had the smallest particle size and largest specific surface area, which were 60 nm and 83m^2/g, respectively. TiOPc synthesized under these conditions also exhibits excellent photoconductivity with charging potential V0, dark decay speed Rd and energy for half-discharging of potential E1/2 being 1160 V, 30 V/s and 0.6 1x.s, respectively.展开更多
Dependency of both source-drain current and current sensitivity of nanosize ISFET biosensor vs. concentration of DNA molecules in aqueous solution theoretically is investigated. In calculations it is carried out effec...Dependency of both source-drain current and current sensitivity of nanosize ISFET biosensor vs. concentration of DNA molecules in aqueous solution theoretically is investigated. In calculations it is carried out effects concerning charge carriers distribution in current channel and concerning carriers’ mobility behavior in high electrical fields in the channel. The influence of DNA molecules on the work of ISFET biosensors is manifested by a change in the magnitude of the gate surface charge. Starting with fairly low concentrations of DNA, ISFET sensors respond to the presence of DNA molecules in an aqueous solution which is manifested by modulation of channel conductance and therefore the source-drain current changes of the field-effect transistor. It is shown that the current sensitivity with respect to concentration of DNA molecules linearly depends on the source-drain voltage and reaches high values.展开更多
The nanosized zirconia was synthesized via solid state reaction in the presence of surfactant. The results indicate that crystal phase of zirconia can be controlled by tuning the synthesis parameters such as OH^-/Zr m...The nanosized zirconia was synthesized via solid state reaction in the presence of surfactant. The results indicate that crystal phase of zirconia can be controlled by tuning the synthesis parameters such as OH^-/Zr molar ratio, crystallizing temperature and time. It can be transformed among amorphous, tetragonal and monoclinic phases. The transformation is driven by particle size. The research shows the nanocrystalline zirconia possesses the higher thermal stability compared with amorphous framework. The ＂glow exotherm＂ can be observed for the amorphous samples. Otherwise, it is in the absence for nanocrystalline samples. Herein, the reason for retention of tetragonal zirconia is demonstrated.展开更多
The terpolymer latex of methyl methacrylate (MMA)/butyl acrylate (BA)/ dimethyl aminoethyl methacrylate (DMAEMA) with diameter of less than 100 nm was prepared by seeding semi-continuous emulsion copolymerization usin...The terpolymer latex of methyl methacrylate (MMA)/butyl acrylate (BA)/ dimethyl aminoethyl methacrylate (DMAEMA) with diameter of less than 100 nm was prepared by seeding semi-continuous emulsion copolymerization using APS (ammonium persulfate) / TMEDA (N,N,N, N-tetramethylethylenediamine) as the redox initiators and SDS (sodium dodecylsulfate) and OP (P-octylpolyethylene glycol phenylether) as co-emulsifiers. The factors that influenced the process stability of the copolymerization and the particle size of the latex were investigated. The addition of aqueous ammonia as coagulation inhibitor provided better process stability of the copoly- merization. The addition of acetic acid as the acidification agent caused a remarkable reduction of the latex particle size.展开更多
Anisotropic SmCo5/Co nanocomposite powders have been prepared by electroless Co deposition on commercial SmCo5 powders with hydrazine as reducer. The Co particles are mainly in the range of 8–27 nm and form dense/con...Anisotropic SmCo5/Co nanocomposite powders have been prepared by electroless Co deposition on commercial SmCo5 powders with hydrazine as reducer. The Co particles are mainly in the range of 8–27 nm and form dense/continuous soft magnetic coatings on the surface of SmCo5 powders. Exchange coupling happened between the coated Co soft magnetic particles and the SmCo5 hard phase. As a result, SmCo5/Co nanocomposite powders with remanence of73.58 emu/g and energy product of 13.74 MGOe were obtained in the optimum condition, as compared with those of70.52 emu/g and 13.40 MGOe for uncoated SmCo5 powders. The effects of Co adding amount on Co particle size, coating morphology, and magnetic properties of SmCo5/Co products were investigated.展开更多
文摘Single-phase homogeneous Ce1-x ZrxO2 solid versed microemulsion method. The structural properties solutions with various compositions were synthesized using the reand performance of Ce1- xZrxO2 were studied using XRD, BET, SEM, HRTEM, TPR and CO oxidation measurements. The results show that in the range of x = 0.4 - 0.5 and x = 0.6 - 1.0, the solid solutions posses the cubic and the tetragonal phase structure, respectively, Solids obtained by the reversed microemulsion method were more homogeneous on the whole range of composition, XRD investigations of the prepared materials did not show segregation of cerium or zirconium oxides, Highly uniform nanosize solid solution particles of ceria-zirconia with high specific area （146.7 m^2·g^-1） were attained under the conditions of this study. The TPR results and CO oxidation measurements indicate that the performance of the CeO2-ZrO2 mixed oxides is strongly related to the composition and structure of the oxides. Enhancement of the activity was found for the catalyst prepared by reversed microemulsion method as compared to the sample prepared by sol-gel method.
文摘A novel method to prepare mesoporous nano-zirconia was developed. Thesynthesis was carried out in the presence of PEO surfactants via a solid-state reaction. Thematerials exhibit a strong diffraction peak at low 2θ angle and their nitrogenadsorption/desorption isotherms are typical of type IV with H1 hysteresis loops. The pore structureimaged by TEM can be described as wormhole domains. The tetragonal zirconia nanocrystals are uniformin size (around 1.5 nm) and their mesopores focus on around 4.6 nm. The zirconia nanocrystal growthis tentatively postulated to be the result of an aggregation mechanism. This study also revealsthat the PEO surfactants can interact with the Zr-O-Zr framework to reinforce the thermal stabilityof zirconia. The ratio of NaOH to ZrOCl_2, crystallization and calcination temperature play animportant role in the synthesis of mesoporous nano-zirconia.
文摘The introduction of mesoporous nanosize zirconia to the catalyst for methanol synthesis dedicates the nanosized catalyst and mesoporous duplicated properties. The catalyst bears the larger surface area, larger mesoporous volume and more uniform diameter, more surface metal atoms and oxygen vacancies than the catalyst prepared with the conventional coprecipitation method. The modification of microstructure and electronic effect could result in the change of the reduced chemical state and decrease of reducuction temperature of copper, donating the higher activity and methanol selectivity to the catalyst. The results of methanol synthesis demonstrate that the Cu^＋ is the optimum active site. Also, the interaction between the copper and zirconia shows the synergistic effect to fulfil the methanol synthesis.
基金This work was financially supported by the National High-Tech Research and Development Pogram of China （＂863＂ Program, Nos. 2002AA325050 and 2004AA302010） the Key Project of Chinese Ministry of Education.（No. 305002）the National Natural Science Foundation of China （Nos. 20325621 and 20236020）.
文摘Functional phthalocyanine （Pc） compounds of H2Pc, TiOPc, FePc and CIAIPc were synthesized with a yield of 46.7%, 91.2%, 37.4% and 34.0%, respectively. Nanosized TiOPc was synthesized via a one-step sol-gel method and effects of surfactant doses, nucleation temperature on TiOPc particle size and photoconductivity were investigated. When re（PEG）： m（TiOPc） was 0.1 and nucleation temperature was 0℃, the as-obtained TiOPc had the smallest particle size and largest specific surface area, which were 60 nm and 83m^2/g, respectively. TiOPc synthesized under these conditions also exhibits excellent photoconductivity with charging potential V0, dark decay speed Rd and energy for half-discharging of potential E1/2 being 1160 V, 30 V/s and 0.6 1x.s, respectively.
文摘Dependency of both source-drain current and current sensitivity of nanosize ISFET biosensor vs. concentration of DNA molecules in aqueous solution theoretically is investigated. In calculations it is carried out effects concerning charge carriers distribution in current channel and concerning carriers’ mobility behavior in high electrical fields in the channel. The influence of DNA molecules on the work of ISFET biosensors is manifested by a change in the magnitude of the gate surface charge. Starting with fairly low concentrations of DNA, ISFET sensors respond to the presence of DNA molecules in an aqueous solution which is manifested by modulation of channel conductance and therefore the source-drain current changes of the field-effect transistor. It is shown that the current sensitivity with respect to concentration of DNA molecules linearly depends on the source-drain voltage and reaches high values.
文摘The nanosized zirconia was synthesized via solid state reaction in the presence of surfactant. The results indicate that crystal phase of zirconia can be controlled by tuning the synthesis parameters such as OH^-/Zr molar ratio, crystallizing temperature and time. It can be transformed among amorphous, tetragonal and monoclinic phases. The transformation is driven by particle size. The research shows the nanocrystalline zirconia possesses the higher thermal stability compared with amorphous framework. The ＂glow exotherm＂ can be observed for the amorphous samples. Otherwise, it is in the absence for nanocrystalline samples. Herein, the reason for retention of tetragonal zirconia is demonstrated.
文摘The terpolymer latex of methyl methacrylate (MMA)/butyl acrylate (BA)/ dimethyl aminoethyl methacrylate (DMAEMA) with diameter of less than 100 nm was prepared by seeding semi-continuous emulsion copolymerization using APS (ammonium persulfate) / TMEDA (N,N,N, N-tetramethylethylenediamine) as the redox initiators and SDS (sodium dodecylsulfate) and OP (P-octylpolyethylene glycol phenylether) as co-emulsifiers. The factors that influenced the process stability of the copolymerization and the particle size of the latex were investigated. The addition of aqueous ammonia as coagulation inhibitor provided better process stability of the copoly- merization. The addition of acetic acid as the acidification agent caused a remarkable reduction of the latex particle size.
基金financially supported by the National Natural Science Foundation of China under Grant No. 51422106the National Basic Research Program of China under Grant No. 2014CB643702+3 种基金the Ningbo Natural Science Foundation of China under Grant No. 2016A610249the Scientific and Technological Project of Zhejiang Province under Grant No. 2013TD08the Ningbo City Scientific and Technological Project under Grant No. 2012B81001the China Postdoctoral Science Foundation under Grant No. 2016M601989 for financial support
文摘Anisotropic SmCo5/Co nanocomposite powders have been prepared by electroless Co deposition on commercial SmCo5 powders with hydrazine as reducer. The Co particles are mainly in the range of 8–27 nm and form dense/continuous soft magnetic coatings on the surface of SmCo5 powders. Exchange coupling happened between the coated Co soft magnetic particles and the SmCo5 hard phase. As a result, SmCo5/Co nanocomposite powders with remanence of73.58 emu/g and energy product of 13.74 MGOe were obtained in the optimum condition, as compared with those of70.52 emu/g and 13.40 MGOe for uncoated SmCo5 powders. The effects of Co adding amount on Co particle size, coating morphology, and magnetic properties of SmCo5/Co products were investigated.
