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Qin Xin

Publications and source records attributed to Qin Xin.

12 recordsLinked to original sources
PubMed2006

A new molecular thermodynamic model for multicomponent Ising lattice.

A new molecular thermodynamic model is developed for multicomponent Ising lattice based on a generalized nonrandom factor from binary system. Predictions of the nonrandom factor and the internal energy of mixing for ternary and quaternary systems match accurately with simulation results. Predictions of liquid-liquid phase equilibrium for ternary systems are in nearly perfect agreement with simulation results, and substantially improved from Flory-Huggins theory and the lattice-cluster theory. The model also satisfactorily correlates the experimental data of real ternary systems. The concise expression and the accuracy of the new model make it well suited for practical engineering applications.

Journal Article↗
PubMed2006

[Photoluminescence properties of nanocrystalline A3(VO4)2:Eu(A = Mg, Ca, Sr and Ba)].

A series of europium doped alkali earth orthovanadates were prepared by Pechini-type sol-gel. The powders were characterized by transmission electron microscopy (TEM), infrared spectrum (IR) and photoluminescence (PL). The results of TEM show that high-quality nanopowders with controlled particle size about 50 nm were prepared. The relation between alkali earth ions and luminescence properties was observed from the results of luminescence spectra. Due to the similar ion radius of Ca2+ ions and Eu3+ ions, Ca3 (VO4 )2:Eu powders exhibit the strongest emission intensity among the four kind of phosphors.

English Abstract↗
PubMed2006

[Photoluminescence properties of A2SnO4 (A = Ca, Sr, Ba) : Eu nanocrystalline].

Nanosized A2SnO4 (A = Ca, Sr, Ba) : 1% Eu with diameters ranging from 50 to 100 nm were synthesized by complex sol-gel methods. The structures and spectral properties of A2SnO4 (A = Ca, Sr, Ba) : Eu were studied by using X-ray powder diffraction (XRD) and luminescence spectra. The experimental results show that Ca2SnO4 : 1% Eu exhibits bright red emission at about 615 nm under UV excitation, which makes it a possible good candidate for FED application. However Sr2SnO4 : 1% Eu and Ba2SnO4 : 1% Eu exhibit orange emission at about 590 nm because in these hosts Eu3+ ions occupy the symmetric sites.

Barium↗
PubMed2005

The synergic effect between Mo species and acid sites in Mo/HMCM-22 catalysts for methane aromatization.

The acid properties of Mo/HMCM-22 catalyst, which is the precursor form of the working catalyst for methane aromatization reaction, and the synergic effect between Mo species and acid sites were studied and characterized by various characterization techniques. It is concluded that Brønsted and Lewis acidities of HMCM-22 are modified due to the introduction of molybdenum. We suggest a monomer of Mo species is formed by the exchange of Mo species with the Brønsted acid sites. On the other hand, coordinate unsaturated sites (CUS) are suggested to be responsible for the formation of newly detected Lewis acid sites. Computer modelling is established and coupling with experimental results, it is then speculated that the effective activation of methane is properly accomplished on Mo species accommodated in the 12 MR supercages of MCM-22 zeolite whereas the Brønsted acid sites in the same channel system play a key role for the formation of benzene. A much more pronounced volcano-typed reactivity curve of the Mo/HMCM-22 catalysts, as compared with that of the Mo/HZSM-5, with respect to Mo loading is found and this can be well understood due to the unique channel structure of MCM-22 zeolite and synergic effect between Mo species and acid sites.

Acids↗
PubMed2005

Size-controllable synthesis of monodispersed SnO2 nanoparticles and application in electrocatalysts.

Size-controllable tin oxide nanoparticles are prepared by heating ethylene glycol solutions containing SnCl(2) at atmospheric pressure. The particles were characterized by means of transmission electron microscopic (TEM), X-ray diffraction (XRD) studies. TEM micrographs show that the obtained material are spherical nanoparticles, the size and size distribution of which depends on the initial experimental conditions of pH value, reaction time, water concentration, and tin precursor concentration. The XRD pattern result shows that the obtained powder is SnO(2) with tetragonal crystalline structure. On the basis of UV/vis and FTIR characterization, the formation mechanism of SnO(2) nanoparticles is deduced. Moreover, the SnO(2) nanoparticles were employed to synthesize carbon-supported PtSnO(2) catalyst, and it exhibits surprisingly high promoting catalytic activity for ethanol electrooxidation.

Journal Article↗
PubMed2004

An improved palladium-based DMFCs cathode catalyst.

A novel carbon-supported palladium-rich Pd3Pt1/C catalyst prepared by a modified polyol process showed a better cell performance than Pt/C in direct methanol fuel cells, which may be attributed to palladium's inactivity to methanol electro-oxidation while exhibiting good performance to oxygen reduction reaction.

Journal Article↗
PubMed2004

[Spectral studies of nanosized LnVO4:Eu (Ln = La, Gd, Y)].

Nanosized LnVO4:Eu (Ln = La, Gd, Y) with diameters ranging from 20 to 50 nm were synthesized by complex sol-gel technique. The structures and spectral properties of LnVO4:Eu were studied by X-ray powder diffraction (XRD), Fourier transform (FT-IR) spectroscopy, luminescence spectra and ultraviolet spectroscopy (UV). The experimental results show that YVO4:Eu and GdVO4:Eu have similar spectral properties because they both have the structure of xenotime, while the structure of LaVO4:Eu belongs to monazite, whose symmetry is inferior to the former vanadates. Consequently the spectral properties of LaVO4:Eu are obviously different from the other two luminescence materials, as the peaks of infrared spectrum and emission spectrum become wider and the number of peaks in UV-Vis spectrum increases.

English Abstract↗
PubMed2003

Anxiolytic-like effect of succinic acid in mice.

The putative anxiolytic activity of succinic acid was examined in male mice by using a number of experimental paradigms of anxiety and compared with that of the known anxiolytic compound diazepam. Use of the elevated plus-maze test revealed that diazepam (1.0, 2.0 and 4.0 mg/kg, PO) or succinic acid (3.0 or 6.0 mg/kg, PO) increased the percentage of entries into open arms and of time spent on open arms. In novel food consumption test, succinic acid (3.0, 6.0, and 12.0 mg/kg, IP) caused significant increases in food intake during 5 min when compared with the vehicle. In the stress-induced hyperthermia test, 40 min after drug administration rectal temperature was measured, succinic acid at dose of 1.5 mg/kg, inhibited stress-induced hyperthermia. Thus, these findings indicated that, in contrast with diazepam, succinic acid exhibits anxiolytic-like effect.

Animals↗