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Abstract: Cubic boron nitride (c-BN) crystals were synthesized in conditions of high temperature and high pressure (HTHP) when different kinds of bonded water were respectively added into the system of h-BN–Mg. All bonded water used in this work could reduce the temperature of growing c-BN compared to that in the system of h-BN–Mg. The c-BN color could change from black to yellow when certain amounts of bonded water, such as NiSO4·6H2O and CuSO4·5H2O, Mg(OH)2, were added. However, c-BN color remained black no matter how much bonded water, such as NiCl2·6H2O, CuCl2·2H2O, and SnCl2·2H2O, was added. The bonded water can be classified into Chlorine-containing bonded water (Cl-BW) and Chlorine-free bonded water (ClF-BW) according to their different characters and effects on the synthesized c-BN color. [Copyright &y& Elsevier]

Abstract: A route for synthesizing high Mg content single-phase wurtzite MgZnO films having band gaps in the solar-blind region is demonstrated by employing molecular beam epitaxy on Al2O3 substrates. Importantly, a low Mg content “quasi-homo” buffer, Mg0.17Zn0.83O, was applied to accommodate a host of structural discrepancies and therefore, avoiding phase separation in a high Mg content film, Mg0.55Zn0.45O, as proved by X-ray diffraction. The Mg fraction in the overgrown single-phase epilayer, Mg0.55Zn0.45O, was confirmed by Rutherford backscattering spectrometry. [Copyright &y& Elsevier]

ZnO/diamond hetero-junction diodes have been fabricated for the first time. The structure of the diode was n-type ZnO film/p-type diamond film on the {111} surface of a crystalline diamond. The contact between the n- and p-type semiconductors was found to be improved. The ratio of forward current to the reverse current exceeded 120 within the range of applied voltages of −4 to +4 V. The diode possessed an optical transmission of 50–70% in 500–700 nm wavelength regions. [Copyright &y& Elsevier]

Low-threshold heterojunctions have been formed from a boron-doped p-type diamond layer grown epitaxially on the {1 1 1} surface of a Si-treated single crystalline cubic boron nitride. The resistivity of the Si-treated cubic boron nitride was 0.1 Ω cm. With the resistivity of 0.1 Ω cm, which is lower than that of the sample prepared by conventional high-temperature and high-pressure method, the turn-on voltage and the highest current of the heterojunction are 0.5 V and 1 mA, respectively. [Copyright &y& Elsevier]

The growing behavior of cubic boron nitride (cBN) crystal in the system of hBN–Mg with bonded water (&z.dbnd6;(HO)2&z.dbnd6;) was investigated at 5.0 GPa and 1100–1500 °C. The results show that, with the existence of bonded water, the grown cBN crystals can appear different color and the growth temperature decreases approximately 300 °C with the pressure fixed at 5.0 GPa by contrast with that in the hBN–Mg system. In addition, the cBN synthesis process is quite different from that when bonded water is absent or that when magnesium is absent. [Copyright &y& Elsevier]

In the present work, the microstructure modifications and corrosion behaviors of a Mg-4Sm alloy treated by high current pulsed electron beam (HCPEB) with different number of pulses were investigated. The microstructure, composition and phase component in the treated surface layers were characterized by using optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS) and transmission electron microscope (TEM). The results showed the dissolution of large Mg 41 Sm 5 segregates, the formation of Mg 41 Sm 5 nano-precipitates and twins in the surface layers after treatments. Electrical impedance spectroscopy (EIS) and polarization tests in the 3.5 wt% NaCl solution showed that the 15 pulses treated Mg-4Sm alloy sample exhibited the lowest corrosion current density, highest corrosion potential and polarization resistance among all samples. This is attributed to the homogeneous microstructure and composition with fewer defects in the surface layer after sufficient number of HCPEB pulses. [ABSTRACT FROM AUTHOR]

Pharmaceutically active compounds (PhACs), which find their way easily into the water sources, are emerging as a major concern for drinking water quality and aquatic species. Therefore, their removal from water sources is a priority from environmental point of view. During the past decade, different methods including membrane separation, adsorption systems and chemical transformation have been evaluated for removal of these compounds. This paper reviews different aspects of PhAC removal by using membrane separation processes, as they have been conventionally known to show high potential in the production of superior quality drinking and industrial water. In brief, osmosis membranes can efficiently remove almost all PhACs though its operational cost is relatively high and nanofiltration (NF) membranes are highly influenced by electrostatic and hydrophobic interaction. Moreover, the efficiency of membrane bioreactors (MBRs) is difficult to predict due to the complex interaction of compounds with microorganisms. To improve the performance and robustness of membrane technology, it is suggested to combine membranes with other systems, such as activated carbon and enzymatic degradation. [ABSTRACT FROM AUTHOR]