Preparation and electrical properties of new oxide ion conductors Ce6-xDyxMoO15-delta (0.0 <= x <= 1.8)

Ce6-xDyxMoO15-delta (0.0 <= x <= 1.8) were synthesized by modified sol-gel method. Structural and electrical properties were investigated by means of X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The XRD patterns showed that the materials were single phase with a cubic fluorite structure. Impedance spectroscopy measurement in the temperature range between 350 degrees C and 800 degrees C indicated a sharp increase in conductivity for the system containing small amount of Dy2O3. The Ce5.6Dy0.4MoO15-delta detected to be the best conducting phase with the highest conductivity (sigma(t) = 8.93 x 10(-3) S cm(-1)) is higher than that of Ce5.6Sm0.4MoO15-delta (sigma(t) = 2.93 x 10(-3) S cm(-1)) at 800 degrees C, and the corresponding activation energy of Ce5.6Dy0.4MoO15-delta (0.994 eV) is lower than that of Ce5.6Sm0.4MoO15-delta (1.002 eV).

Preparation and Electrical Properties of New Oxide Ion Conductors Ce6-xGdxMoO15-delta (0.0 <= x <= 1.8)

A series of oxide ion conductors Ce6-xGdxMoO15-delta (0.0 <= x <= 1.8) have been prepared by the sol-gel method. Their properties were characterized by differential thermal analysis/thermogravimetry (DTA/TG), X-ray diffraction (XRD), Raman, IR, X-ray photoelectron spectroscopy (XPS), and AC impedance spectroscopy. The XRD patterns showed that the materials were single phase with a cubic fluorite structure. The conductivity of Ce6-xGdxMoO15-delta increases as x increases and reaches the maximum at x = 0.15. The conductivity of Ce4.5Gd1.5MoO15-delta is sigma(t) = 3.6 x 10(-3) S/cm at 700 degrees C, which is higher than that of Ce4.5/6Gd1.5/6O2-delta (sigma(t) = 2.6 x 10(-3) S/cm), and the corresponding activation energy of Ce4.5Gd1.5MoO15-delta (0.92 eV) is lower than that of Ce4.5/6Gd1.5/6O2-delta (1.18 eV).

Structural analysis of monoterpene glycosides extracted from Paeonia lactiflora Pall. using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry and high-performance liquid chromatography/electrospray ionization tandem mass spectrometry

Paeoniflorin standard was first investigated by electrospray ionization Fourier transform ion cyclotron resonance tandem mass spectrometry (ESI-FTICR-MS/MS) using a sustained off-resonance irradiation (SORI) collision-induced dissociation (CID) method at high mass resolution. The experimental results demonstrated that the unambiguous elemental composition of product ions can be obtained at high mass resolution. Comparing MS/MS spectra and the experimental methods of hydrogen and deuterium exchange, the logical fragmentation pathways of paeoniflorin have been proposed. Then, the extracts of the traditional Chinese medicine Paeonia lactiflora Pall. were analyzed by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). By comparison with the ESI-FTICR-MS/MS data of paeoniflorin, the isomers paeoniflorin and albiflorin in Paeonia lactiflora Pall. have been identified using HPLC/MS with CID in an ion trap and in-source CID. Furthermore, using the characteristic fragmentation pathways, the retention times (t(R)) in HPLC and MS/MS spectra, the structures of three other kinds of monoterpene glycoside compounds have been identified on-line without time-consuming isolation.

A study of isomeric diglycosyl flavonoids by SORI CID of Fourier transform ion cyclotron mass Spectrometry in negative ion mode

High-resolution Sustained off resonance irradiation (SORI) CID was employed to distinguish four pairs of isomeric diglycosyl flavonoids in the negative mode using the electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICR MS). All of these isomers can be distinguished via MS/MS data. For these diglycosyl flavones and flavanones, the deprotonated alpha 1-->6 linkage diglycosyl flavonoids produce fewer fragments than the alpha 1-->2 linkage type compounds and the Retro-Diels-Alder (RDA) reaction in MS/MS only takes place when the aglycone is a flavanone and glycosylated with an alpha 1-->2 intersaccharide linkage disaccharide. The deprotonation sites after collisional activation are discussed according to the high mass accuracy and high-resolution data of tandem spectrometry. Some of these high-resolution SORI CID product ions from alpha 1-->2 linkage diglycosyl flavonoids involve multibond cleavages; the possible mechanism is discussed based on the computer modeling using Gaussian 03 program package at the B3LYP/6-31G level of theory. Unambiguous elementary composition data provides fragmentation information that has not been reported previously.

Facile synthesis and photoluminescence of europium ion doped LaF3 nanodisks

LaF3 : Eu3+ (5.0 mol-% EU3+) nanodisks with perfect crystallinity were successfully synthesized by a simple method. The synthesis was carried out in an aqueous solution at room temperature without the use of templates or organic additives, The mechanism of formation of the nanodisks was explored, and the fluoride source (KBF4) is believed to play a key role in controlling the morphology of the final product. Furthermore, the size of the disk can be simply moderated by varying the concentration of the initial reactants. The room-temperature photoluminescence of LaF3 : Eu3+ with different morphologies and sizes were also investigated, and the results indicate that the emission intensity of the product is strongly affected by their size, shape, and other factors.