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Nickel cobalt (Ni-Co) oxides with various Ni/Co ratios are synthesized by using a sol-gel process. Electrochemical performance, microstructure, morphology and BET surface area are found strongly related to Ni and Co concentration. Increasing Co concentration changes the oxide microstructure from NiO crystal dominate structure (Ni:Co = 1:1 and 1:2) to Co3O4 dominate structure (Ni:Co = 1:4 and 0:1). A maximum specific capacitance of 1539 Fg−1 was obtained for Ni-Co (Ni:Co = 1:2) oxide at a current density of 1Ag−1, and this capacitance is similar to that of RuO2. A systematic study shows that the Ni-Co oxide (1:2) has a mesoporous structure with a high BET surface area of ∼ 315 m2 g−1 and porous size of ∼ 4.7 nm, which is favorable for the charge/dischargeprocess of a supercapacitor.

BackgroundLivestock rearing is one of the oldest and most important types of smallholder farming worldwide. The sustainability of livestock production depends on the efficient utilization of locally available resources. Some traditional methods of raising livestock may offer valuable lessons in this regard. This study documented and evaluated local knowledge of wild forage plants in the Dulongjiang area in Southwest China in the context of rearing mithun (Bos frontalis) in order to provide a sound evidence base for tree fodder selection and the establishment of integrated tree-crop-livestock systems.MethodsThe snowball technique was used to identify key informants with specific knowledge about the topic. Free listing and semi-structured interviews were conducted with 58 households. Participatory investigation and transit walks were used to investigate potential fodder species. Ethnobotanical information was collected, documented and organized.ResultsOverall, 142 wild forage plants from 58 families and 117 genera were identified. Species of the Poaceae, Rosaceae and Urticaceae families were most abundant, with 16, 14 and 11 species respectively identified as fodder plants. Our results indicated that tree/shrub forage plays a major role in the diet of mithun, unlike that of other ruminants. Mithun prefers to browse and move around the forest in search of food, particularly rough and even barbed leaves. Tree species like Debregeasia orientalis, Saurauia polyneura and Rubus species were identified as being important fodder sources. Farmers in this area have traditionally relied on common property resources such as community-managed forests and grasslands to feed their livestock. Farmers have strong incentive to raise mithuns rather than other livestock species due to Dulong people’s cultural preferences.ConclusionsThe wide variety of plants cited by the informants demonstrate the importance of traditional knowledge in gathering information about forage resources. This diversity also offers the prospect of identifying promising species which could be used as fodder plants. Identifying such species and tree fodder species in particular could help smallholder farmers to integrate trees, livestock and crops as part of a sustainable farming system.

Nanocrystalline tin sulfide (SnS) was prepared by chemical bath deposition, and the photovoltaic behavior of SnS/TiO 2 was studied. The X-ray diffraction pattern and transmission electron microscopy revealed an ∼6 nm SnS polycrystalline orthorhombic structure. The SnS film exhibited a band gap of 1.3 eV, and its absorption coefficient was more than 1 × 10 4 cm -1 in the visible light range. The electrical conductivity activation energy of the SnS film was 0.22 eV, determined when the sample was heated in the temperature range of 111-144 °C. Although the sample was insulating at room temperature, photovoltaic behavior was found in a SnS/TiO 2 structure, with an open-circuit voltage (V oc ) of 471 mV, a short-circuit current density (J sc ) of 0.3 mA/cm 2 , and the conversion efficiency (η) of 0.1% under 1 sun illumination. The properties of SnS and the reasons behind the photovoltaic phenomenon of SnS/TiO 2 are discussed.

The authors studied the surface optical phonon and A1(LO) in ZnO submicron crystals as well as ZnO single crystals with submicron surface structures by employing ultraviolet Raman scattering. The small variation in Raman frequency of A1(LO), when the growth condition is changed, is mainly caused by the crystal imperfection via two mechanisms: one is the frequency lowering by native defects and the other is the frequency increasing due to the tilt of c-axis of ZnO crystals away from the surface normal direction that leads to the mixing of A1(LO) and E1(LO). The evolution of Raman features, before and after dielectric coatings, in conjunction with the photoluminescence, provides clear-cut evidence for the observation of a surface optical phonon. The frequency of the observed surface mode is lowered by the existence of surface states, and the surface states can be effectively reduced by the dielectric coatings.

The electrical conductivity of P-doped ZnO can be controlled by changing the P-doping concentration. With increasing P concentration, ZnO can be changed from n type to p type. At the same time, a redshift of the band gap energy is observed by using the photoluminescence spectroscopy and UV-visible spectrophotometer. X-ray diffraction results show that lattice spacings of ZnO increase with P concentration, which indicates that P substitutes O, and this leads to a lattice spacing increase and an optical band gap energy decrease.

Effect of high-energy electron beam irradiation on the properties of ZnO thin films prepared by magnetron sputtering

Transparent indium zinc oxide (IZO) ohmic contacts to phosphor-doped n-type ZnO have been formed. The resistance, transmittance, and phase reliability of the contacts were investigated. As deposited, an ohmic contact was formed with a specific contact resistance of about 1.1×10−4Ωcm2 and the transmittance of the ZnO∕IZO (520∕350nm) film was more than 75% in the 450–1100nm wavelength range. After annealing at 400°C for 5min in a vacuum (2×10−5mbar), the specific contact resistance was reduced by about two orders of magnitude to 3.8×10−6Ωcm2, while maintaining the contact stability and high optical transparency.