The features of transmissions in underwater sensor networks (UWSNs) include lower transmission rate, longer delay time, and higher power consumption when compared with terrestrial radio transmissions. The negative effects of transmission collisions deteriorate in such environments. Existing UWSN routing protocols do not consider the transmission collision probability differences resulting from different transmission distances. In this paper, we show that collision probability plays an important role in route selection and propose an energy-efficient routing protocol (DRP), which considers the distance-varied collision probability as well as each node's residual energy. Considering these 2 issues, DRP can find a path with high successful transmission rate and high-residual energy. In fact, DRP can find the path producing the longest network lifetime, which we have confirmed through theoretical analysis. To the best of our knowledge, DRP is the first UWSN routing protocol that uses transmission collision probability as a factor in route selection. Simulation results verify that DRP extends network lifetime, increases network throughput, and reduces end-to-end delay when compared with solutions without considering distance-varied collision probability or residual energy. KEYWORDS energy-efficient routing protocol, network lifetime, transmission collisions, underwater sensor networks 1 Int J Commun Syst. 2017;30:e3303.wileyonlinelibrary.com/journal/dac

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Polycrystalline Cu-doped ZnIn 2 S 4 samples were grown on fluorine doped-tin-oxide-coated glass substrates using chemical bath deposition. The effect of [Cu]/[Cu+Zn] molar ratio in solution bath on the structural, optical and photoelectrochemical properties of the samples was investigated. From the results of X-ray diffraction (XRD) patterns of samples, a small shift in the peaks to a higher-angle was observed with the increase in Cu content in the film. The thicknesses and direct band gaps of the samples are in the ranges of 520-1260 nm and 2.51-2.09 eV, as obtained from surface profile measurement and transmittance/reflectance spectra, respectively. The highest photoelectrochemical response of samples was 1.15 mA/cm 2 at an external potential of + 1.0 V vs. an Ag/AgCl electrode in 0.5 M K 2 SO 4 solution under illumination using a 300W Xe lamp system with the light intensity set at 100 mW/cm 2 .

Among variety of 1-D materials, ZnO nanowires (NWs) has attracted extensive attention due to its specific physical properties. For wide-ranging applications in nanoscale electronic devices, p-type ZnO NWs even have excellent electrical properties. In this work, ZnO NWs were synthesized with P2O5 as a dopant source via the hydrothermal method which used zinc acetate and hexamethylenetetramine (HMTA) mixed solution as the precursor. The morphology and aspect ratio of aligned phosphorus-doped ZnO NWs arrays were examined by field emission scanning electron microscope (FESEM). The effect of various phosphorus-doped concentration were systematically discussed. The X-ray diffractometer (XRD) and the high resolution transmission electron microscope (HRTEM) image indicated that the NWs are single-crystalline with <0001> growth direction. The results of temperature-dependent photoluminescence (PL) spectra revealed that both phosphorus-doped and undoped ZnO NWs show a UV light emission (370–380 nm) and a defect-related emission (400–750 nm). The phosphorus-doped ZnO NWs enhanced defect-related emission intensity. The electrical transport properties and field effect transistors (FETs) confirmed that p-type conductivity of the single phosphorus-doped ZnO NW. The phosphorus-doped ZnO NWs were successfully synthesized by hydrothermal method and showed characteristics of the p-type conductivity.