Time filter

Source Type

Dezhou, China

Wang X.-Z.,Dezhou University
Journal of Materials Science: Materials in Electronics | Year: 2014

LaPO4:Eu nanoparticles were synthesized from different phosphate sources by the method of precipitation. The influences of phosphate sources on properties of LaPO4:Eu nanoparticles were studied. The LaPO 4:Eu sample synthesized from (NH4)2HPO 4 has the uniform morphology and good dispersion. The excitation spectra show the Eu-O charge-transfer band and f-f orbital transitions of Eu3+. The strong absorption of charge transfer band (CTB) can be measured when H3PO4 is used as the phosphate source. However, there is a red shift of CTB when (NH4)2HPO 4 and Na5P3O10 are used as phosphate sources, which indicates the increase in O2--Eu3+ distance and the decrease in charge transfer energy. The emission spectra show different emission transitions originating from 5D0 state (5D0 → 7Fj) of Eu3+. The life times of the Eu3+ ions are determined to be 2.176, 4.576, and 5.608 ms for the samples synthesized from H3PO4, Na5P3O10 and (NH4) 2HPO4, respectively. © 2014 Springer Science+Business Media New York.

Xin B.,Shandong University | Xin B.,Dezhou University | Hao J.,Shandong University
Chemical Society Reviews | Year: 2014

Supported ionic liquids (SILs), which refer to ionic liquids (ILs) immobilized on supports, are among the most important derivatives of ILs. The immobilization process of ILs can transfer their desired properties to substrates. Combination of the advantages of ILs with those of support materials will derive novel performances while retaining properties of both moieties. SILs have been widely applied in almost all of fields involving ILs, and have brought about drastic expansion of the ionic liquid area. As green media in organic catalytic reactions, based on utilizing the ability of ILs to stabilize the catalysts, they have many advantages over free ILs, including avoiding the leaching of ILs, reducing their amount, and improving the recoverability and reusability of both themselves and catalysts. This has critical significance from both environmental and economical points of view. As novel functional materials in surface science and material chemistry, SILs are ideal surface modifying agents. They can modify and improve the properties of solids, such as wettability, lubricating property, separation efficiency and electrochemical response. With the achievements in the field of ILs, using magnetic nanoparticles (MNPs) to SILs has drawn increasing attention in catalytic reactions and separation technologies, and achieved substantial progress. The combination of MNPs and ILs renders magnetic SILs, which exhibit the unique properties of ILs as well as facile separation by an external magnetic field. In this article, we focus on imidazolium-based ILs covalently grafted to non-porous and porous inorganic materials. The excellent stability and durability of this kind of SILs offer a great advantage compared with free ILs and IL films physically adsorbed on substrates without covalent bonds. Including examples from our own research, we overview mainly the applications and achievements of covalent-linked SILs in catalytic reactions, surface modification, separation technologies and electrochemistry. This journal is © the Partner Organisations 2014.

LiCo 1-xMn xPO 4/C cathode materials are selectively synthesized by a solvothermal method in ethylene glycol solvent using glucose, LiCl, H 3PO 4, MnCl 2·4H 2O, and Co(NO 3) 2·6H 2O as precursors. The obtained samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) and the electrochemical performances are also evaluated using a LAND CT2001A battery test system at room temperature. XRD result demonstrates the formation of LiCo 1-xMn xPO 4 solid solution and the enlarged channels are benefit for Li + migration. SEM graph indicates that the particle size of LiCo 0.5Mn 0.5PO 4/C is about several hundred nanometers and aggregates to large particles located in the range of 2-3 μm. TEM image illustrates that the core/shell-structured LiCo 0.5Mn 0.5PO 4/C solid solution is indeed obtained by this method. The high specific surface area (35 m 2/g) of LiCo 0.5Mn 0.5PO 4/C could make this solid solution contact with the electrolyte more sufficiently and benefit for Li + transportation. The capacity, flat voltage, and cyclical stability of LiCo 1-xMn xPO 4/C are improved compared to LiMnPO 4 and LiCoPO 4 due to the improved electronic conductivity and lithium-ion conductivity which resulted from carbon coating and foreign element incorporation. © 2012 Springer-Verlag.

Wang X.-Z.,Dezhou University
Journal of Materials Science: Materials in Electronics | Year: 2014

Spherical MWO4:Tb3+ (M = Ca, Sr, Ba) particles were synthesized by a hydrothermal route at 180°C for 10 h. The synthesized MWO4:Tb3+ particles were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and luminescence spectroscopy. The XRD and FT-IR results show that MWO 4:Tb3+ particles with a scheelite-type crystal structure were synthesized successfully. The SEM and TEM results show that uniform spherical particles in the range of hundreds of nanometers were obtained. The possible growth mechanism may be attributed to a typical Ostwald ripening process. The excitation spectra of MWO4:Tb3+ phosphors show a strong absorption band of the WO4 2- group and some weak absorption bands of Tb3+ ions. The emission spectra of MWO 4:Tb3+ phosphors show the characteristic emission bands of Tb3+ ions. CaWO4:Tb3+ sample has the highest excitation and emission intensity. © 2014 Springer Science+Business Media New York.

The purpose of this paper is to extend the homotopy perturbation method to fractional heat transfer and porous media equations with the help of the Laplace transform. The fractional derivatives described in this paper are in the Caputo sense. The algorithm is demonstrated to be direct and straightforward, and can be used for many other non-linear fractional differential equations.

Discover hidden collaborations