Aiming at improving the properties of magnesia carbon materials,silicon aluminum carbide(Al_(4)SiC_(4))containing materials were prepared using industrial aluminum powder,silicon carbide powder,and graphite as raw mat...Aiming at improving the properties of magnesia carbon materials,silicon aluminum carbide(Al_(4)SiC_(4))containing materials were prepared using industrial aluminum powder,silicon carbide powder,and graphite as raw materials,and activated alumina powder as an additive,mixing thoroughly,pressing into cylinders and then firing at 1200℃for 30 min in a carbon embedded atmosphere by the microwave method.The effects of the aluminum powder addition(20%and 24%,by mass)and activated alumina powder addition(0,3%,5%and 7%,by mass)on the microwave synthesis of Al_(4)SiC_(4) as well as the effect of the obtained Al_(4)SiC_(4) containing material on the properties of magnesia carbon bricks were studied.The results show that:compared with the samples with 20%aluminum powder,those with 24%aluminum powder generate more Al_(4)SiC_(4).With the activated alumina powder addition increasing from 0 to 7%,the amount of Al_(4)SiC_(4) generated increases first and then decreases.Compared with the sample without activated alumina powder,the samples with activated alumina powder show lower bulk density and higher apparent porosity.With the activated alumina powder addition increasing from 3%to 7%,the bulk density of the samples increases first and then decreases,while the apparent porosity of the samples shows an opposite trend.The optimal additions are 24%aluminum powder and 5%activated alumina powder,and Al_(4)SiC_(4) synthesized in this sample has a hexagonal plate structure.With the synthesized Al_(4)SiC_(4) containing material added,the magnesia carbon brick has slightly increased cold modulus of rupture,basically the same modulus of elasticity and improved oxidation resistance.展开更多
A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-typ...A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-type Li2FeSiO4 sample with uniform and fine particle sizes is successfully and fast synthesized by microwave heating at 700 ℃ in 12 rain. And the obtained Li2FeSiO4 materials show better electrochemical performance and microstructure than those of Li2FeSiO4 sample by the conventional solidstate reaction. ？2009 Yan Bing Cao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
A Eu^3＋-doped CaCO3 phosphor with red emission was prepared by microwave synthesis. The scanning electron microscopy （SEM） image and laser particle size analysis show that the CaCO3：Eu^3＋ particles are needle-lik...A Eu^3＋-doped CaCO3 phosphor with red emission was prepared by microwave synthesis. The scanning electron microscopy （SEM） image and laser particle size analysis show that the CaCO3：Eu^3＋ particles are needle-like in the length range of 5.0-10.0 μm. The results of X-ray diffraction （XRD） analysis, Fourier transform infrared spectroscopy （FT-IR）, and Raman spectroscopy indicate that pure aragonite CaCO3：Eu^3＋ is prepared using microwave irradiation and the Eu^3＋ ion as a luminescence center inhabits the site of Ca^2＋. The photoluminescence excitation （PLE） spectrum shows that the strong broad band at around 270 nm and weak sharp lines in 300-550 nm are assigned to the charge transfer band of Eu^3＋-O^2- and intra-configurational 4f-4f transitions of Eu^3＋, respectively. The photoluminescence （PL） spectrum implies that the red luminescence can be attributed to the transitions from the ^5D0 excited level to the ^7FJ （J = 0, 1, 2, 3, 4） levels of Eu^3＋ ions with the mainly electric dipole transition ^5D0 → ^7F2 （614 and 620 nm）, and the Eu^3＋ ions prefer to occupy the low symmetric site in the crystal lattice.展开更多
In order to lower the raw materials cost and develop a novel cathode materials for intermediate temperature solid oxide fuel cell(ITSOFC), using mixed rare earth replacing the expensive pure La2O3 as the raw materials...In order to lower the raw materials cost and develop a novel cathode materials for intermediate temperature solid oxide fuel cell(ITSOFC), using mixed rare earth replacing the expensive pure La2O3 as the raw materials, the powders of Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ(Ln = the mixed rare earth, x =0.05, 0. 10, 0. 15) for the applications as the cathode materials were prepared by microwave sintering process. The crystal structure and the particles morphology of the obtained powders were characterized by XRD and SEM, the electrical conductivity of all samples sintered at 1200℃for 3 h was also measured as the function of the temperature from 100 to 800℃by DC four-probe method in air. The experimental results show that due to the influence of mixed rare earth the powders of Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δsynthesized at 1200℃for 0.5 h with the mean particle size of 1 ~ 20μm was of perovskite and cubic fluorite phase as well a little SrO phase, the electrical conductivity of the samples decreases with the adding Ca2+ content, and are all higher than 100 S·cm -1from 500 to 700℃when x≤0.10. Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ. can meet the demand of the electrical properties for the cathode materials in ITSOFC.展开更多
A fast, green and readily reproducible microwave-based method for the production of high quality silver nanoparticles （AgNPs） in high yield is presented. Starch is used as a stabilizing agent with few pentose differ...A fast, green and readily reproducible microwave-based method for the production of high quality silver nanoparticles （AgNPs） in high yield is presented. Starch is used as a stabilizing agent with few pentose different reducing carbohydrates as D-ribose, D-arabinose and L-arabinose. From the UV-vis peak profile spectra of the solutions of the silver nanoparticles, the authors have investigated the size of the NPs together with the average diameter, shape, and aggregation state of the colloidal AgNPs. TEM measurements and EDX analysis have confirmed the morphology of our AgNPs.展开更多
The thioglycollic acid（TGA） as a capping agent, CdTe/TGA quantum dots（QDs） with excellent properties were synthesized under microwave irradiation. The TGA/Cd/Te molar ratios, reaction time, temperature and p H are...The thioglycollic acid（TGA） as a capping agent, CdTe/TGA quantum dots（QDs） with excellent properties were synthesized under microwave irradiation. The TGA/Cd/Te molar ratios, reaction time, temperature and p H are the crucial factors for properties of QDs. The QDs were characterized by UVvis absorption and fluorescence spectra, transmission electron microscopy and Fourier transform infrared spectroscopy. The experimental results show that when the p H value is 11.5 and molar ratio of TGA：Cd：Te is 1.2：1：0.4 at 100 ℃ heating for 15 min, the resulted QDs exhibit a high fluorescence quantum yield of 78%. The fluorescence full width at half maximum（FHMW） of QDs is around 23 nm. The products are spherical with average size of 3-5 nm. There is a strong coordination effect between TGA and Cd2＋. Moreover, the results of interaction between as-made QDs and bovine serum albumin（BSA） suggest that the QDs-BSA binding reaction is a static quenching. The negative values of free energy（△G〈0） suggest that the binding process is spontaneous, △H〈0 and △S〈0 show that hydrogen bonds and van der Waals interactions play a major role in the binding reaction between QDs and BSA.展开更多
W<sup>6+</sup>-doped TiO<sub>2</sub> was prepared by sodium tungsten (VI) and titanium sulfate with sodium dodecyl sulfate as surfactant under microwave irradiation. The samples were characteri...W<sup>6+</sup>-doped TiO<sub>2</sub> was prepared by sodium tungsten (VI) and titanium sulfate with sodium dodecyl sulfate as surfactant under microwave irradiation. The samples were characterized by X-ray diffraction (XRD) and Scanning electron micrograph (SEM). The results showed that the as-prepared nanocomposite of inventory molar ratio of 2% calcined at 500°C for 2 h was anatase. The SEM showed that the majority of the catalyst was a relatively flake structure, and some fine particles attached to it. We also studied the photocatalytic activity of the as-prepared samples by using degradation of methyl orange. The factors including inventory molar ratio and concentration of W<sup>6+</sup>-doped, calcined temperature, amount of hydrogen peroxide and acidity of solution were investigated. When the catalyst was 1.0 g/L, pH was 2, C(H<sub>2</sub>O<sub>2</sub>) was 3 mL/L, the degradation rate of TiO<sub>2</sub> for methyl orange of 20 mg/L reached 79.63% in 40 min.展开更多
La1-xSrxCo1-yFeyO3 cathode materials for solid oxide fuel cells were prepared by the microwave synthesis method.The reaction mechanism was studied using a thermal analysis method.The influences of microwave synthesis ...La1-xSrxCo1-yFeyO3 cathode materials for solid oxide fuel cells were prepared by the microwave synthesis method.The reaction mechanism was studied using a thermal analysis method.The influences of microwave synthesis conditions were examined and the characteristics of the samples were determined by X-ray diffraction and scanning electron microscopy.It was found that the optimum conditions were the microwave power of 800 W and the reaction time of 40 min.Samples with perosvkite-type crystal structure were obtained.The samples consist of uniformly distributed internal particles and the particle size is less than 1 μm.展开更多
LiMn 2O 4 was synthesized rapidly by microwave heating.The product phases of the microwave synthesis and conventional solid-state synthesis were comparatively invesitigated.The capacity of microwave synthesis produc...LiMn 2O 4 was synthesized rapidly by microwave heating.The product phases of the microwave synthesis and conventional solid-state synthesis were comparatively invesitigated.The capacity of microwave synthesis product decreases relatively slow.The lithium ion can be inserted into and extracted from the spinel framework structure fluently after cycling.But the capacity of the conventional solid-state synthesis product is more remarkably lowered.The spinel framework structure was destroyed which hindered the lithium ion from inserting and extracting.The influential factors of the process parameters are discussed such as heat preservation time, pre-heating at 400℃ for 24h and coupled agent.展开更多
Bis{2-[（2,4-dichloro-phenytimino）-methyl]-4,6-diiodo-phenol}-copper（II） （1） has been synthesized and its structure determined by X-ray diffraction. It crystallizes in the monoclinic system, space group P21/n wit...Bis{2-[（2,4-dichloro-phenytimino）-methyl]-4,6-diiodo-phenol}-copper（II） （1） has been synthesized and its structure determined by X-ray diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 14.7558（17）, b = 20.770（2）, c = 20.3260（19） A, β = 90.6110（10）°, V= 6229.2（11） A3 and Z = 8. The Cu atom is surrounded by two O atoms and two N atoms from two 2-[（2,4-diehloro-phenylimino）-methyl]-4,6-diiodo-phenol molecules to form a tetrahedral coordination environment. The complex is linked into a column by weak intermolecular interactions.展开更多
In this paper, CeVO<sub>4</sub>/FeVO<sub>4</sub> nanocomposites were prepared by direct feeding microwave synthesis method with nine water iron nitrate (Fe(NO<sub>3</sub>)3&bull...In this paper, CeVO<sub>4</sub>/FeVO<sub>4</sub> nanocomposites were prepared by direct feeding microwave synthesis method with nine water iron nitrate (Fe(NO<sub>3</sub>)3•9H<sub>2</sub>O), cerium nitrate hexahydrate (Ce(NO<sub>3</sub>)3•6H<sub>2</sub>O) and ammonium metavanadate (NH<sub>4</sub>VO<sub>3</sub>) as raw material and Sodium Dodecyl Sulfate (SDS) as surfactant. Then X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM) were used to observe the CeVO<sub>4</sub>/FeVO<sub>4</sub> nanocomposites. SEM image showed that the as-prepared CeVO<sub>4</sub>/ FeVO<sub>4</sub> nanocomposites calcined at 773 Kis formated of small particles aggregation irregular sheet structure. We studied the photocatalytic activity of the as-prepared samples by using degradation of methyl orange in visible light. The results showed that the photocatalytic activity of CeVO<sub>4</sub>/FeVO<sub>4</sub> nanocomposites were very well. It found that when the catalyst calcined at 773 K was 0.10 g, and 0.5 mL hydrogen peroxide joined as well as, pH was 2.0, the degradation ratio of catalyst for methylene orange of 100 mL 5 mg/L reached 98.63% in 40 min.展开更多
We obtained TiNiSn-based half-Heusler Hf_(x)Ti_(1-x)NiSn_(0.97)Sb_(0.03)bulks with 85%-96%relative densities via 5-min microwave synthesis and 20-min microwave sintering in sealed vacuum.The phase composition and micr...We obtained TiNiSn-based half-Heusler Hf_(x)Ti_(1-x)NiSn_(0.97)Sb_(0.03)bulks with 85%-96%relative densities via 5-min microwave synthesis and 20-min microwave sintering in sealed vacuum.The phase composition and microstructure of samples were characterized by X-ray diffractometer(XRD)and scanning electron microscopy(SEM).Thermoelectric(TE)properties were measured,i.e.,Seebeck coefficient(S),electrical resistivity(ρ),and thermal conductivity(κ)through Seebeck coefficient/resistance analysis system(S/RAs)and laser flash thermal analyzer(LFT).The results show that the nearly single phase exists after microwave sintering.The grain sizes and the number of grain boundaries decrease with increase in Hf-doping amount due to an increase in point defects.The matrix grains for Hf_(0.1)Ti_(0.9)NiSn_(0.97)Sb_(0.03)are~10μm.The nanoscle pores and precipitates are present as second phases in matrix grain.The real composition for Hf_(0.1)Ti_(0.9)NiSn_(0.97)Sb_(0.03)matrix grain is Hf_(3.51)Ti_(28.76)-Ni_(34.76)Sn_(31.55)Sb_(1.43).The variation trends of electrical resistivity,Seebeck coefficient,power factor,and thermal conductivity were analyzed in detail.The maximum figure of merit(ZT)of 0.46 is obtained for Hf_(0.1)Ti_(0.9-)NiSnSn_(0.97)Sb_(0.03)at 723 K.The innovation route exhibits advantages for predation of TE bulks when compared to the conventional methods,especially in terms of efficiency while it still maintains TE performance.展开更多
In order to reduce the oxidation and volatilization caused by Mg element in the traditional methods for synthesizing Mg2Si compounds,Mg2Si thermoelectric materials were prepared by solid state reaction and microwave r...In order to reduce the oxidation and volatilization caused by Mg element in the traditional methods for synthesizing Mg2Si compounds,Mg2Si thermoelectric materials were prepared by solid state reaction and microwave radiation techniques.Structure and phase composition of the materials were investigated by X-ray diffraction.The electrical conductivity,Seebeck coefficient and thermal conductivity were measured as a function of temperature from 300 to 700 K.It is found that high purity Mg2Si powders can be obtained with excessive content of 8% Mg from the stoichiometric Mg2Si at 853 K and 2.5 kW for 30 min.A maximum dimensionless figure of merit,ZT,of about 0.13 was obtained for Mg2Si at 600 K.展开更多
In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx （x=0.2, 0.4, 0.6, 0.8） solid solutions, microwave irradiation techniques were used in pr...In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx （x=0.2, 0.4, 0.6, 0.8） solid solutions, microwave irradiation techniques were used in preparing them as thermoelectric materials. Structure and phase composition of the obtained materials were investigated by X-ray diffraction （XRD）. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature from 300 to 750 K. It is found that Mg2Si1-xSnx solid solutions are well formed with excessive content of 5% （molar fraction） Mg from the stoichiometric MgESil.xSnx under microwave irradiation. A maximum dimensionless figure of merit, ZT, of about 0.26 is obtained for Mg2Si1-xSnx solid solutions at about 500 K for x=0.6.展开更多
Metal nanoparticles of multi-principal element alloys(MPEA)with a single crystalline phase have been synthesized by flash heating/cooling of nanosized metals encapsulated in micelle vesicles dispersed in an oil phase(...Metal nanoparticles of multi-principal element alloys(MPEA)with a single crystalline phase have been synthesized by flash heating/cooling of nanosized metals encapsulated in micelle vesicles dispersed in an oil phase(e.g.,cyclohexane).Flash heating is realized by selective absorption of a microwave pulse in metals to rapidly heat metals into uniform melts.The oil phase barely absorbs microwave and maintains the low temperature,which can rapidly quench the high-temperature metal melts to enable the flash cooling process.The precursor ions of four metals,including Au,Pt,Pd,and Cu,can be simultaneously reduced by hydrazine in the aqueous solution encapsulated in the micelle vesicles.The resulting metals efficiently absorb microwave energy to locally reach a temperature high enough to melt themselves into a uniform mixture.The duration of microwave pulse is crucial to ensure the reduced metals mix uniformly,while the temperature of oil phase is still low to rapidly quench the metals and freeze the single-phase crystalline lattices in alloy nanoparticles.The microwave-enabled flash heating/cooling provides a new method to synthesize single-phase MPEA nanoparticles of many metal combinations when the appropriate water-in-oil micelle systems and the appropriate reduction reactions of metal precursors are available.展开更多
Introduction With the development of scientific technology, people continuously search for new methods which can accelerate reactions. Nowadays as a new technology, microwave irradiation has gained much practical impo...Introduction With the development of scientific technology, people continuously search for new methods which can accelerate reactions. Nowadays as a new technology, microwave irradiation has gained much practical importance in chemical reactions. Microwave irradiation has been applied successfully to the areas, such as inorganic synthesis, the prepara-展开更多
A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide（Ⅲ） chloride to form complexes of the type [Ln（HISA）2Cl3], where, Ln=La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（...A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide（Ⅲ） chloride to form complexes of the type [Ln（HISA）2Cl3], where, Ln=La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, or Gd（Ⅲ） and HISA= [（2-hydroxybenzaldehyde）-3-isatin]bishydrazone. Both reactions were carried out under microwave conditions. The ligand and the metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, UV visible, infrared, far infrared, and proton NMR spectral data. The ligand acted as neutral tridentate, coordinating through the carbonyl oxygen, azomethine nitrogen, and phenolic oxygen without deprotonation. The ligand and lanthanum（Ⅲ） complex were subjected to X-ray diffraction studies. The X-ray diffraction pattern of ligand exhibited its crystalline nature and that of the lanthanum（Ⅲ） complex indicated its amorphous character. The thermal decomposition behaviour of the complex, [La（HISA）2Cl3], was examined in the temperature range of 40-800 ℃ using TG, DTG, and DTA. The ligand and the metal complexes were screened for their antifungal activities.展开更多
An efficient synthesis of cinchona alkaloid-derived ligands based on solvent-free microwave-assisted reaction was described. The coupling of 1,4-dichlorophthalazine or 3,6-dichloropyridazine with quinine, cinchonine o...An efficient synthesis of cinchona alkaloid-derived ligands based on solvent-free microwave-assisted reaction was described. The coupling of 1,4-dichlorophthalazine or 3,6-dichloropyridazine with quinine, cinchonine or cinchonidine provide bis-or monocinchona alkaloid-derived ligands in moderate to good yields （52-89%） within 15 min under optimum microwave conditions.展开更多
In recent years,two-dimensional(2D)ternary materials have attracted wide attention due to their novel properties which can be achieved by regulating their chemical composition with a very great degree of freedom and a...In recent years,two-dimensional(2D)ternary materials have attracted wide attention due to their novel properties which can be achieved by regulating their chemical composition with a very great degree of freedom and adjustable space.However,as for the precise synthesis of 2D ternary materials,great challenges still lie ahead that hinder their further development.In this work,we demonstrated a simple and reliable approach to synthesize 2D ternary-layered BiOCl crystals through a microwave-assisted space-confined process in a short time(<3 minutes).Their ultraviolet(UV)detection performance was analyzed systematically.The photodetectors based on the as-obtained BiOCl platelets demonstrate high sensitivity to 266-nm laser illumination.The responsivity is calculated to be8 A/W and the response time is up to be18 ps.On the other hand,the device is quite stable after being exposed in the ambient air within 3 weeks and the response is almost unchanged during the measurement.The facile and fast synthesis of single crystalline BiOCl platelets and its high sensitivity to UV light irradiation indicate the potential optoelectronic applications of 2D BiOCl photodetectors.展开更多
The new lanthanum (Ⅲ) and praseodymium (Ⅲ) complexes of the general formula [Ln(L)3] (Ln=La(Ⅲ) or Pr(Ⅲ); LK=potassium salt of dithiocarbazinates) were prepared by both, conventional thermal and by the use of micro...The new lanthanum (Ⅲ) and praseodymium (Ⅲ) complexes of the general formula [Ln(L)3] (Ln=La(Ⅲ) or Pr(Ⅲ); LK=potassium salt of dithiocarbazinates) were prepared by both, conventional thermal and by the use of microwave technology. Elemental analyses, electrical conductance, magnetic moment and electronic, infrared, far-infrared, 1H and 13C NMR spectral studies were used to characterize the complexes. The molecular weights of few complexes were determined by FAB-mass spectra. Nephelauxetic ratio, covalency parameter and bonding parameter for these complexes were also calculated. The probable structures of the complexes were proposed. The antifungal and antibacterial activities of the complexes were evaluated. The activities were correlated with the structures of the compounds.展开更多
基金This work was funded by Luoyang Major Science and Technology Innovation Project(2301009A)Henan Province Key ResearchandDevelopment Project(231111230200).
文摘Aiming at improving the properties of magnesia carbon materials,silicon aluminum carbide(Al_(4)SiC_(4))containing materials were prepared using industrial aluminum powder,silicon carbide powder,and graphite as raw materials,and activated alumina powder as an additive,mixing thoroughly,pressing into cylinders and then firing at 1200℃for 30 min in a carbon embedded atmosphere by the microwave method.The effects of the aluminum powder addition(20%and 24%,by mass)and activated alumina powder addition(0,3%,5%and 7%,by mass)on the microwave synthesis of Al_(4)SiC_(4) as well as the effect of the obtained Al_(4)SiC_(4) containing material on the properties of magnesia carbon bricks were studied.The results show that:compared with the samples with 20%aluminum powder,those with 24%aluminum powder generate more Al_(4)SiC_(4).With the activated alumina powder addition increasing from 0 to 7%,the amount of Al_(4)SiC_(4) generated increases first and then decreases.Compared with the sample without activated alumina powder,the samples with activated alumina powder show lower bulk density and higher apparent porosity.With the activated alumina powder addition increasing from 3%to 7%,the bulk density of the samples increases first and then decreases,while the apparent porosity of the samples shows an opposite trend.The optimal additions are 24%aluminum powder and 5%activated alumina powder,and Al_(4)SiC_(4) synthesized in this sample has a hexagonal plate structure.With the synthesized Al_(4)SiC_(4) containing material added,the magnesia carbon brick has slightly increased cold modulus of rupture,basically the same modulus of elasticity and improved oxidation resistance.
基金supported by National Key Technology R&D Program of China(No.2007BAE12B01-1)Science and Technology Planning Program of Hunan Province,China(No.2008GK3015)
文摘A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-type Li2FeSiO4 sample with uniform and fine particle sizes is successfully and fast synthesized by microwave heating at 700 ℃ in 12 rain. And the obtained Li2FeSiO4 materials show better electrochemical performance and microstructure than those of Li2FeSiO4 sample by the conventional solidstate reaction. ？2009 Yan Bing Cao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金supported by the National Natural Science Foundation of China (No. 10476024) the Science and Technology Bureau of Sichuan Province, China (No. 2006J13-059)
文摘A Eu^3＋-doped CaCO3 phosphor with red emission was prepared by microwave synthesis. The scanning electron microscopy （SEM） image and laser particle size analysis show that the CaCO3：Eu^3＋ particles are needle-like in the length range of 5.0-10.0 μm. The results of X-ray diffraction （XRD） analysis, Fourier transform infrared spectroscopy （FT-IR）, and Raman spectroscopy indicate that pure aragonite CaCO3：Eu^3＋ is prepared using microwave irradiation and the Eu^3＋ ion as a luminescence center inhabits the site of Ca^2＋. The photoluminescence excitation （PLE） spectrum shows that the strong broad band at around 270 nm and weak sharp lines in 300-550 nm are assigned to the charge transfer band of Eu^3＋-O^2- and intra-configurational 4f-4f transitions of Eu^3＋, respectively. The photoluminescence （PL） spectrum implies that the red luminescence can be attributed to the transitions from the ^5D0 excited level to the ^7FJ （J = 0, 1, 2, 3, 4） levels of Eu^3＋ ions with the mainly electric dipole transition ^5D0 → ^7F2 （614 and 620 nm）, and the Eu^3＋ ions prefer to occupy the low symmetric site in the crystal lattice.
基金Project supported by the National High-Tech Development Plan of China (2001AA51580) the Sweden-Asia Partnership Program (DNR6964)+1 种基金the Natural Science Foundation of Liaoning Province (20062145) the Education Department of Liaoning Province (05L073)
文摘In order to lower the raw materials cost and develop a novel cathode materials for intermediate temperature solid oxide fuel cell(ITSOFC), using mixed rare earth replacing the expensive pure La2O3 as the raw materials, the powders of Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ(Ln = the mixed rare earth, x =0.05, 0. 10, 0. 15) for the applications as the cathode materials were prepared by microwave sintering process. The crystal structure and the particles morphology of the obtained powders were characterized by XRD and SEM, the electrical conductivity of all samples sintered at 1200℃for 3 h was also measured as the function of the temperature from 100 to 800℃by DC four-probe method in air. The experimental results show that due to the influence of mixed rare earth the powders of Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δsynthesized at 1200℃for 0.5 h with the mean particle size of 1 ~ 20μm was of perovskite and cubic fluorite phase as well a little SrO phase, the electrical conductivity of the samples decreases with the adding Ca2+ content, and are all higher than 100 S·cm -1from 500 to 700℃when x≤0.10. Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ. can meet the demand of the electrical properties for the cathode materials in ITSOFC.
文摘A fast, green and readily reproducible microwave-based method for the production of high quality silver nanoparticles （AgNPs） in high yield is presented. Starch is used as a stabilizing agent with few pentose different reducing carbohydrates as D-ribose, D-arabinose and L-arabinose. From the UV-vis peak profile spectra of the solutions of the silver nanoparticles, the authors have investigated the size of the NPs together with the average diameter, shape, and aggregation state of the colloidal AgNPs. TEM measurements and EDX analysis have confirmed the morphology of our AgNPs.
基金Funded by the China Scholarship Council and Hubei Provincial Department of Education of China(201308420539)the Science and Technology Research Program of Hubei Provincial Department of Education of China(Q20131105,B2016008)+1 种基金the Coal Conversion and New Carbon Materials Hubei Key Laboratory(Wuhan University of Science and Technology(WKDM201505,WKDM201507)the Wuhan University of Science and Technology Foundation of China(z00980,2014XG006)
文摘The thioglycollic acid（TGA） as a capping agent, CdTe/TGA quantum dots（QDs） with excellent properties were synthesized under microwave irradiation. The TGA/Cd/Te molar ratios, reaction time, temperature and p H are the crucial factors for properties of QDs. The QDs were characterized by UVvis absorption and fluorescence spectra, transmission electron microscopy and Fourier transform infrared spectroscopy. The experimental results show that when the p H value is 11.5 and molar ratio of TGA：Cd：Te is 1.2：1：0.4 at 100 ℃ heating for 15 min, the resulted QDs exhibit a high fluorescence quantum yield of 78%. The fluorescence full width at half maximum（FHMW） of QDs is around 23 nm. The products are spherical with average size of 3-5 nm. There is a strong coordination effect between TGA and Cd2＋. Moreover, the results of interaction between as-made QDs and bovine serum albumin（BSA） suggest that the QDs-BSA binding reaction is a static quenching. The negative values of free energy（△G〈0） suggest that the binding process is spontaneous, △H〈0 and △S〈0 show that hydrogen bonds and van der Waals interactions play a major role in the binding reaction between QDs and BSA.
文摘W<sup>6+</sup>-doped TiO<sub>2</sub> was prepared by sodium tungsten (VI) and titanium sulfate with sodium dodecyl sulfate as surfactant under microwave irradiation. The samples were characterized by X-ray diffraction (XRD) and Scanning electron micrograph (SEM). The results showed that the as-prepared nanocomposite of inventory molar ratio of 2% calcined at 500°C for 2 h was anatase. The SEM showed that the majority of the catalyst was a relatively flake structure, and some fine particles attached to it. We also studied the photocatalytic activity of the as-prepared samples by using degradation of methyl orange. The factors including inventory molar ratio and concentration of W<sup>6+</sup>-doped, calcined temperature, amount of hydrogen peroxide and acidity of solution were investigated. When the catalyst was 1.0 g/L, pH was 2, C(H<sub>2</sub>O<sub>2</sub>) was 3 mL/L, the degradation rate of TiO<sub>2</sub> for methyl orange of 20 mg/L reached 79.63% in 40 min.
文摘La1-xSrxCo1-yFeyO3 cathode materials for solid oxide fuel cells were prepared by the microwave synthesis method.The reaction mechanism was studied using a thermal analysis method.The influences of microwave synthesis conditions were examined and the characteristics of the samples were determined by X-ray diffraction and scanning electron microscopy.It was found that the optimum conditions were the microwave power of 800 W and the reaction time of 40 min.Samples with perosvkite-type crystal structure were obtained.The samples consist of uniformly distributed internal particles and the particle size is less than 1 μm.
基金theNationalNaturalScienceFoundationofChina (No 5 9972 0 2 6 )theMajorProjectofMinistryofEducation
文摘LiMn 2O 4 was synthesized rapidly by microwave heating.The product phases of the microwave synthesis and conventional solid-state synthesis were comparatively invesitigated.The capacity of microwave synthesis product decreases relatively slow.The lithium ion can be inserted into and extracted from the spinel framework structure fluently after cycling.But the capacity of the conventional solid-state synthesis product is more remarkably lowered.The spinel framework structure was destroyed which hindered the lithium ion from inserting and extracting.The influential factors of the process parameters are discussed such as heat preservation time, pre-heating at 400℃ for 24h and coupled agent.
基金National Natural Science Foundation of China (Projects 30772627)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China
文摘Bis{2-[（2,4-dichloro-phenytimino）-methyl]-4,6-diiodo-phenol}-copper（II） （1） has been synthesized and its structure determined by X-ray diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 14.7558（17）, b = 20.770（2）, c = 20.3260（19） A, β = 90.6110（10）°, V= 6229.2（11） A3 and Z = 8. The Cu atom is surrounded by two O atoms and two N atoms from two 2-[（2,4-diehloro-phenylimino）-methyl]-4,6-diiodo-phenol molecules to form a tetrahedral coordination environment. The complex is linked into a column by weak intermolecular interactions.
文摘In this paper, CeVO<sub>4</sub>/FeVO<sub>4</sub> nanocomposites were prepared by direct feeding microwave synthesis method with nine water iron nitrate (Fe(NO<sub>3</sub>)3•9H<sub>2</sub>O), cerium nitrate hexahydrate (Ce(NO<sub>3</sub>)3•6H<sub>2</sub>O) and ammonium metavanadate (NH<sub>4</sub>VO<sub>3</sub>) as raw material and Sodium Dodecyl Sulfate (SDS) as surfactant. Then X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM) were used to observe the CeVO<sub>4</sub>/FeVO<sub>4</sub> nanocomposites. SEM image showed that the as-prepared CeVO<sub>4</sub>/ FeVO<sub>4</sub> nanocomposites calcined at 773 Kis formated of small particles aggregation irregular sheet structure. We studied the photocatalytic activity of the as-prepared samples by using degradation of methyl orange in visible light. The results showed that the photocatalytic activity of CeVO<sub>4</sub>/FeVO<sub>4</sub> nanocomposites were very well. It found that when the catalyst calcined at 773 K was 0.10 g, and 0.5 mL hydrogen peroxide joined as well as, pH was 2.0, the degradation ratio of catalyst for methylene orange of 100 mL 5 mg/L reached 98.63% in 40 min.
基金financially supported by the National Natural Science Foundation of China (Nos.51574134 and 51574042)the Joint Fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals (No.18LHPY016)Anhui University Outstanding Young Talent Support Program (Key Project) (No.gxyq ZD2017039)。
文摘We obtained TiNiSn-based half-Heusler Hf_(x)Ti_(1-x)NiSn_(0.97)Sb_(0.03)bulks with 85%-96%relative densities via 5-min microwave synthesis and 20-min microwave sintering in sealed vacuum.The phase composition and microstructure of samples were characterized by X-ray diffractometer(XRD)and scanning electron microscopy(SEM).Thermoelectric(TE)properties were measured,i.e.,Seebeck coefficient(S),electrical resistivity(ρ),and thermal conductivity(κ)through Seebeck coefficient/resistance analysis system(S/RAs)and laser flash thermal analyzer(LFT).The results show that the nearly single phase exists after microwave sintering.The grain sizes and the number of grain boundaries decrease with increase in Hf-doping amount due to an increase in point defects.The matrix grains for Hf_(0.1)Ti_(0.9)NiSn_(0.97)Sb_(0.03)are~10μm.The nanoscle pores and precipitates are present as second phases in matrix grain.The real composition for Hf_(0.1)Ti_(0.9)NiSn_(0.97)Sb_(0.03)matrix grain is Hf_(3.51)Ti_(28.76)-Ni_(34.76)Sn_(31.55)Sb_(1.43).The variation trends of electrical resistivity,Seebeck coefficient,power factor,and thermal conductivity were analyzed in detail.The maximum figure of merit(ZT)of 0.46 is obtained for Hf_(0.1)Ti_(0.9-)NiSnSn_(0.97)Sb_(0.03)at 723 K.The innovation route exhibits advantages for predation of TE bulks when compared to the conventional methods,especially in terms of efficiency while it still maintains TE performance.
基金Project (2009BB4228) supported by the Natural Science Foundation Project of Chongqing Science and Technology Commission,ChinaProject (CK2010Z09) supported by the Research Foundation of Chongqing University of Science and Technology,China
文摘In order to reduce the oxidation and volatilization caused by Mg element in the traditional methods for synthesizing Mg2Si compounds,Mg2Si thermoelectric materials were prepared by solid state reaction and microwave radiation techniques.Structure and phase composition of the materials were investigated by X-ray diffraction.The electrical conductivity,Seebeck coefficient and thermal conductivity were measured as a function of temperature from 300 to 700 K.It is found that high purity Mg2Si powders can be obtained with excessive content of 8% Mg from the stoichiometric Mg2Si at 853 K and 2.5 kW for 30 min.A maximum dimensionless figure of merit,ZT,of about 0.13 was obtained for Mg2Si at 600 K.
基金Project(2009BB4228) supported by the Natural Science Foundation of Chongqing City,ChinaProject(CK2010Z09) supported by the Research Foundation of Chongqing University of Science and Technology,China
文摘In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx （x=0.2, 0.4, 0.6, 0.8） solid solutions, microwave irradiation techniques were used in preparing them as thermoelectric materials. Structure and phase composition of the obtained materials were investigated by X-ray diffraction （XRD）. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature from 300 to 750 K. It is found that Mg2Si1-xSnx solid solutions are well formed with excessive content of 5% （molar fraction） Mg from the stoichiometric MgESil.xSnx under microwave irradiation. A maximum dimensionless figure of merit, ZT, of about 0.26 is obtained for Mg2Si1-xSnx solid solutions at about 500 K for x=0.6.
基金supported by the National Science Foundation(NSF)of United States under NSF award(No.1946912)Materials characterizations were partially performed at Temple Materials Institute(TMI).Use of the Center for Nanoscale Materials,an Office of Science user facility+1 种基金was supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,under Contract No.DE-AC02-06CH11357This research used resources of the Advanced Photon Source,a U.S.Department of Energy(DOE)Office of Science User Facility,operated for the DOE Office of Science by Argonne National Laboratory under Contract No.DE-AC02-06CH11357.
文摘Metal nanoparticles of multi-principal element alloys(MPEA)with a single crystalline phase have been synthesized by flash heating/cooling of nanosized metals encapsulated in micelle vesicles dispersed in an oil phase(e.g.,cyclohexane).Flash heating is realized by selective absorption of a microwave pulse in metals to rapidly heat metals into uniform melts.The oil phase barely absorbs microwave and maintains the low temperature,which can rapidly quench the high-temperature metal melts to enable the flash cooling process.The precursor ions of four metals,including Au,Pt,Pd,and Cu,can be simultaneously reduced by hydrazine in the aqueous solution encapsulated in the micelle vesicles.The resulting metals efficiently absorb microwave energy to locally reach a temperature high enough to melt themselves into a uniform mixture.The duration of microwave pulse is crucial to ensure the reduced metals mix uniformly,while the temperature of oil phase is still low to rapidly quench the metals and freeze the single-phase crystalline lattices in alloy nanoparticles.The microwave-enabled flash heating/cooling provides a new method to synthesize single-phase MPEA nanoparticles of many metal combinations when the appropriate water-in-oil micelle systems and the appropriate reduction reactions of metal precursors are available.
文摘Introduction With the development of scientific technology, people continuously search for new methods which can accelerate reactions. Nowadays as a new technology, microwave irradiation has gained much practical importance in chemical reactions. Microwave irradiation has been applied successfully to the areas, such as inorganic synthesis, the prepara-
文摘A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide（Ⅲ） chloride to form complexes of the type [Ln（HISA）2Cl3], where, Ln=La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, or Gd（Ⅲ） and HISA= [（2-hydroxybenzaldehyde）-3-isatin]bishydrazone. Both reactions were carried out under microwave conditions. The ligand and the metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, UV visible, infrared, far infrared, and proton NMR spectral data. The ligand acted as neutral tridentate, coordinating through the carbonyl oxygen, azomethine nitrogen, and phenolic oxygen without deprotonation. The ligand and lanthanum（Ⅲ） complex were subjected to X-ray diffraction studies. The X-ray diffraction pattern of ligand exhibited its crystalline nature and that of the lanthanum（Ⅲ） complex indicated its amorphous character. The thermal decomposition behaviour of the complex, [La（HISA）2Cl3], was examined in the temperature range of 40-800 ℃ using TG, DTG, and DTA. The ligand and the metal complexes were screened for their antifungal activities.
基金the National Natural Science Foundation of China (No.20672141) for financial support of this work.
文摘An efficient synthesis of cinchona alkaloid-derived ligands based on solvent-free microwave-assisted reaction was described. The coupling of 1,4-dichlorophthalazine or 3,6-dichloropyridazine with quinine, cinchonine or cinchonidine provide bis-or monocinchona alkaloid-derived ligands in moderate to good yields （52-89%） within 15 min under optimum microwave conditions.
基金National Research Foundation Singapore,Grant/Award Numbers:AStar QTE program.,AcRF Tier 2 MOE2017-T2-2-002,MOE Tier 2 MOE2015-T2-2-007,MOE Tier 3 MOE2018-T3-1-002,MOE2016-T2-2-153,MOE2017-T2-2-136,NRF-RF2013-08.MOE Tier 1 RG7/18,NRF2017-NRF-ANR0022DPSNatural Science Foundation of Jiangsu Province,Grant/Award Number:BK20160994+1 种基金This work was supported by the Singapore National Research Foundation under NRF RF Award No.NRF-RF2013-08.MOE Tier 1 RG7/18,MOE Tier 2 MOE2015-T2-2-007,MOE2016-T2-2-153,MOE2017-T2-2-136,MOE Tier 3 MOE2018-T3-1-002,AcRF Tier 2 MOE2017-T2-2-002,NRF2017-NRF-ANR0022DPS,and A*Star QTE program.Dan Tian thanks the National Nature Science Foundation of China(Grant No.21601086)the Natural Science Foundation of Jiangsu Province(BK20160994)for financial support.
文摘In recent years,two-dimensional(2D)ternary materials have attracted wide attention due to their novel properties which can be achieved by regulating their chemical composition with a very great degree of freedom and adjustable space.However,as for the precise synthesis of 2D ternary materials,great challenges still lie ahead that hinder their further development.In this work,we demonstrated a simple and reliable approach to synthesize 2D ternary-layered BiOCl crystals through a microwave-assisted space-confined process in a short time(<3 minutes).Their ultraviolet(UV)detection performance was analyzed systematically.The photodetectors based on the as-obtained BiOCl platelets demonstrate high sensitivity to 266-nm laser illumination.The responsivity is calculated to be8 A/W and the response time is up to be18 ps.On the other hand,the device is quite stable after being exposed in the ambient air within 3 weeks and the response is almost unchanged during the measurement.The facile and fast synthesis of single crystalline BiOCl platelets and its high sensitivity to UV light irradiation indicate the potential optoelectronic applications of 2D BiOCl photodetectors.
文摘The new lanthanum (Ⅲ) and praseodymium (Ⅲ) complexes of the general formula [Ln(L)3] (Ln=La(Ⅲ) or Pr(Ⅲ); LK=potassium salt of dithiocarbazinates) were prepared by both, conventional thermal and by the use of microwave technology. Elemental analyses, electrical conductance, magnetic moment and electronic, infrared, far-infrared, 1H and 13C NMR spectral studies were used to characterize the complexes. The molecular weights of few complexes were determined by FAB-mass spectra. Nephelauxetic ratio, covalency parameter and bonding parameter for these complexes were also calculated. The probable structures of the complexes were proposed. The antifungal and antibacterial activities of the complexes were evaluated. The activities were correlated with the structures of the compounds.
