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Partially oxidized niobium carbonitride has been examined to apply to a non-platinum cathode for polymer electrolyte fuel cells ͑PEFCs͒. NbC 0.5 N 0.5 powder was partially oxidized in an inert gas containing 30 or 100 ppm O 2 at 1000°C for 10 h. NbO 2 or Nb 2 O 5 was observed in the X-ray diffraction patterns of the specimens. The catalytic activity for the oxygen reduction reaction ͑ORR͒ of the specimen that contained Nb 2 O 5 was higher than that of the specimens with NbO 2 and as-prepared NbC 0.5 N 0.5 . X-ray photoelectron spectra suggested that the highest oxidation state of Nb affected the improvement of the catalytic activity for the ORR.Polymer electrolyte fuel cells ͑PEFCs͒ have drawn much attention because they have many advantages as power sources for residential and transportation applications such as high power density, low operating temperature, and high energy-conversion efficiency. However, PEFCs still have serious problems to commercialize widely. A large amount of Pt nanoparticles was used in both the anode and cathode electrodes of PEFCs. In particular, the Pt nanoparticles at the cathode have a large overpotential of oxygen reduction reaction ͑ORR͒ and dissolve at high potentials. In addition, the natural resource of Pt is too limited to make many fuel cell vehicles. Therefore, development of an alternative material with low cost, high stability, and high catalytic activity for the ORR is vital. It is reported that transition metal oxide-based compounds have high stability and some catalytic activity for the ORR. 1-6 In particular, partially oxidized tantalum carbonitride͑Ta-CN͒ has the onset potential for the ORR of 0.83 V vs a reversible hydrogen electrode ͑RHE͒ in 0.1 mol dm −3 H 2 SO 4 at 30°C. 3 Although partially oxidized Ta-CN would be one of the possible candidates as a non-platinum cathode, the resource of tantalum is as limited as that of platinum. The resource of niobium, 4.4 ϫ 10 3 kton, is 2 orders of magnitude greater than that of tantalum, ͑43 kton͒. Ohnishi et al. reported that oxidebased niobium compounds prepared by reactive sputtering have some catalytic activity for the ORR. 7 In this study, we evaluated the partially oxidized niobium carbonitride ͑Nb-CN͒ as a non-platinum cathode for PEFCs. Nb-CN was synthesized by a mixture of metal Nb and carbon powder at 1500°C in N 2 atmosphere. The effect of the partial oxidation of the Nb-CN on the ORR activity was examined. ExperimentalNb-CN powder was synthesized by using a mixture of Nb powder ͑Ͻ45 m, 99.9%, High Purity Chemicals, Japan͒ and carbon black ͑average particle size of Ͻ1 m, 99.95%, SEC Corp.͒ as starting materials. The Nb and carbon black powders were mixed with a composition of Nb:C = 1:0.55 in molar ratio using a mortar and pestle. A cylindrical-shaped tablet ͑10 mm ϫ 5 mm͒ of their mixed powder was made by uniaxial pressing at 2 MPa, and then the tablet was heat-treated in an alumina tube furnace in N 2 atmosphere at 1500°C for 10 h, resulting in the formation of Nb-CN powder. The partial oxidation of Ta-CN was very...

− A sensitive and specific liquid chromatographic method coupled with tandem mass spectrometry (LC-MS/ MS) was developed for the analysis of ambroxol (active moiety of acebrophylline). After acetonitrile precipitation of proteins from plasma samples, ambroxol and the domperidone (internal standard, IS) were eluted on a C18 column. The isocratic mobile phase was consisted of 10 mM ammonium acetate and methanol (10 : 90, v/v), with flow rate at 0.2 mL/min. A tandem mass spectrometer, as detector, was used for quantitative analysis in positive mode by a multiple reaction monitoring mode to monitor the m/z 379.2→264.0 and the m/z 426.2→175.1 transitions for ambroxol and the IS, respectively. Twenty four healthy Korean male subjects received two capsules (100 mg × 2) of either the test or the reference formulation of acebrophylline HCl in a 2 × 2 crossover study, this was followed by a 1week washout period between either formulation. AUC 0-t (the area under the plasma concentration-time curve) was calculated by the linear trapezoidal rule. C max (maximum plasma drug concentration) and T max (time to reach C max ) were compiled from the plasma concentration-time data. The 90% confidence intervals for the log transformed data were acceptable range of log 0.8 to log 1.25 (e.g., log 0.8964 -log 0.9910 for AUC 0-t log 0.8690 -log 1.0750 for C max ). The major parameters, AUC 0-t and C max met the criteria of Korea Food and Drug Administration for bioequivalence indicating that Acephyll ® capsule (test) is bioequivalent to Surfolase ® capsule (reference).

Bulk Ti3(Al1-nGen)C2 (n=0, 0.3, 0.5, 0.7, 1.0)were synthesized by a reactive hot pressing of TiCX (x=0.6), Al and Ge powder mixture at 1400 °C for 1 h under 25 MPa. A series of Ti3(Al1-nGen)C2 was successfully synthesised by a hot pressing through a direct liquid-solid reaction between Al-Ge melt and TiCx, and simultaneous densification. Synthesized bulk Ti3(Al1-nGen)C2 was maintained a typical layered structure as shown in other ternary carbide such as Ti3AlC2 and Ti3GeC2. With increasing Al or Ge contents in Ti3(Al1-nGen)C2, both of Vickers hardness and flexural strength of Ti3(Al1-nGen)C2 were increased compared to those of pure Ti3AlC2 and Ti3GeC2 . The maximum flexural strength of Ti3(Al1-nGen)C2 (n=0.3) was about 600 MPa, which was about 3 times higher than that of pure Ti3GeC2. The Vickers hardnesses of Ti3(Al1-nGen)C2 and Ti3AlC2 were slightly decreased with increasing an indentation load.