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Abstract: V2O3 and VN nanocrystals have been synthesized by the decomposition of the precursor NH4VO3 and following nitridation in an autoclave with metallic Na flux at 450–600°C. X-ray powder diffraction (XRD) recorded the evolution process of the reaction from precursor NH4VO3 to hexagonal V2O3 and then to NaCl-type VN. In addition, the products were characterized by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). [Copyright &y& Elsevier]

In this paper, a kind of multi-wavelength fiber laser based on highly erbium-doped fiber (HEDF) is introduced. A new type of HEDF is used as the gain medium and four-wave Mixing (FWM) in single mode fiber(SMF) is used to suppress mode competition of the laser. And then, a nonlinear optical fiber loop mirror(NOLM) is added to ring cavity to optimize the experimental structure. The flatness of the output spectrum and side mode suppression ratio(SMSR) are studied. At last, the stability of the experimental system is analyzed by taking two peak light waves near the center wavelength as an example. [ABSTRACT FROM AUTHOR]

Abstract: Niobium diboride (NbB2) nanorods have been successfully synthesized by the reaction of NbCl5 with NaBH4 in the temperature range of 550–650 °C in an autoclave. X-ray diffraction (XRD) and electron diffraction show that the as-prepared products are NbB2. Transmission electron micrographs shows that the average diameter of samples are in the range of 50–60 nm and the length is up to 600 nm. The mechanism for the formation of crystalline NbB2 is proposed. [Copyright &y& Elsevier]

Abstract: We describe one convenient synthesis route to boron nitride (BN) nanotube by the reaction of boron powder, iron oxide, and ammonium chloride at 600°C for 12h. Characterized by XRD, FTIR, XPS, TEM and SAED, the composition and morphology of the products are confirmed. The possible reaction mechanism is also discussed. [Copyright &y& Elsevier]

The introduction of catalyst on anode of solid oxide fuel cell (SOFC) has been an effective way to alleviate the carbon deposition when utilizing biogas as the fuel. A series of La 0.6 Sr 0.4 Co 1-x Ni x O 3-δ (x = 0, 0.2, 0.4, 0.6, 0.8) oxides are synthesized by sol-gel method and used as catalysts precursors for biogas dry reforming. The phase structure of La 0.6 Sr 0.4 Co 1-x Ni x O 3-δ oxides before and after reduction are characterized by X-ray diffraction (XRD). The texture properties, carbon deposition, CH 4 and CO 2 conversion rate of La 0.6 Sr 0.4 Co 1-x Ni x O 3-δ catalysts are evaluated and compared. The peak power density of 739 mW cm−2 is obtained by a commercial SOFC with La 0.6 Sr 0.4 Co 0.4 Ni 0.6 O 3-δ catalyst at 850 °C when using a mixture of CH 4 : CO 2 = 2:1 as fuel. This shows a great improvement from the cell without catalyst for internal dry reforming, which is attributed to the formation of NiCo alloy active species after reduction in H 2 atmosphere. The results indicate the benefits of inhibiting the carbon deposition on Ni-based anode through introducing the La 0.6 Sr 0.4 Co 0.4 Ni 0.6 O 3-δ catalyst precursor. Additionally, the dry reforming technology will also help to convert part of the exhaust heat into chemical energy and improve the efficiency of SOFC system with biogas fuel. • Dry reforming of biogas between methane and CO 2 is studied. • The texture properties and catalytic activity of La 0.6 Sr 0.4 Co 1-x Ni x O 3-δ catalysts are examined systematically. • The presence of NiCo alloy active species can possible alleviate the carbon deposition of anode layer of single cell. • The single cell with La 0.6 Sr 0.4 Co 0.4 Ni 0.6 O 3-δ catalyst exhibits 739 mW cm−2 at internal reforming of CH 4 :CO 2 = 2:1 at 850. [ABSTRACT FROM AUTHOR]

This study demonstrated the application of a tungsten oxide electrode to the measurement of ultralow liquid flow velocity based on streaming potential, using a pH glass electrode and temperature sensor to compensate for changes in open circuit potential induced by pH and temperature, respectively. A change in flow velocity on the surface of the tungsten oxide electrode caused the expected shift in its open circuit potential. Experimental results showed that the open circuit potential was linear relative to the logarithmic flow velocity, and the flow sensor exhibited excellent reproducibility and a large dynamic range, with the ratio between measurable maximum and minimum flow velocity surpassing 60:1. Moreover, a higher sensitivity was observed in the alkaline solution relative to the acidic solution, indicating that the alkaline solution is more suitable for this type of measurement. In conclusion, the tungsten oxide flow sensor provides a cheap, simple, adaptable, and energy-saving solution for the measurement of ultralow liquid flow velocity. [ABSTRACT FROM AUTHOR]

In this study, a novel solid-state pH sensor based on an untreated platinum sheet was investigated. Chronopotentiometry using positive and negative currents was applied to effect the interconversion of Pt and PtO. To eliminate the influence of concentration polarization, a galvanostatic double-pulse method was applied for pH measurement. The consecutively applied currents were +100, +3, −100, and −3 μA for excitation times of 0.5, 1, 0.5, and 1 s, respectively. Stable potentials under the small currents were obtained which could be used to determine pH. The platinum sheet electrode exhibited near-Nernstian behavior in the pH range 2–12, with fitted lines having slopes of −44.2 and −51.1 mV/pH unit under the positive and negative currents, respectively. Overall, excellent linearity and reproducibility could be achieved. Moreover, the temperature responses for the method in pH 4, 6.86, and 9.18 buffer solutions obeyed the Nernst equation, and further supported the proposed mechanism for pH determination. In conclusion, this new detection method provides a solid-state, long-lived, and adaptable solution for pH measurement. [ABSTRACT FROM AUTHOR]