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The pollution characteristics of the typical antibiotic resistance genes (ARGs) in the sediments of the sea area adjacent to the Yangtze Estuary, China were investigated with both seasonal and spatial insights. The positive rates of sulfonamides sul1, sul2, tetracycline tetW and quinolone gyrA resistance genes in the sediments of all sampling sites were 100%, indicating that the sea area adjacent to the Yangtze Estuary were extensively polluted by these ARGs. Occupying a dominance in most sampling sites, sul1 was found to be the dominant resistance gene in the sediments of the sea area adjacent to the Yangtze Estuary. In terms of seasonal variation characteristics, the absolute abundances of the ARGs in flood season were higher than those in dry season. In terms of spatial distribution characteristics, the absolute abundances of the ARGs in the southern sites were mostly higher than those in the northern sites, and the high abundance sites were mostly located near the coast. Different ARGs also showed different spatial distribution characteristics. The disclosure of the pollution characteristics of the typical ARGs in the sediments of the sea area adjacent to the Yangtze Estuary can provide valued information for protecting the environment of this area as well as the Yangtze River Basin.

Ammonia recovery from wastewater was achieved by developing a bioelectrochemical membrane-absorbed ammonia system with authigenic acid and base. With the microbial electrolysis desalination, the cathode chamber of the system produced base to raise wastewater pH value and convert ammonium to free ammonia, and the acid chamber simultaneously produced acid to supply the absorption chamber and recover ammonia via membrane absorption. Ammonia was finally recovered as (NH4)2SO4 in the authigenic acid solution. The removal and recovery efficiencies of ammonia were up to 97.3 ± 0.5% and 68.1 ± 3.4% with low initial ammonium concentration (20 mM), respectively. Both high applied voltage and low initial ammonium concentration could accelerate the ammonia recovery, while the exorbitant salt concentration in the desalination chamber could delay the ammonia recovery. The energy consumption of this system for ammonia recovery was 2.91 kWh/kg-N, which is relatively low compared with some reported processes. The results demonstrate that the developed system has the potential for energy-saving ammonia recovery from wastewater.

In this paper, a new printed ultra-wideband (UWB) power divider with notched band using square ring multiple-mode resonator (SRMMR) is presented. The characteristics of the proposed SRMMR are investigated by using even- and odd-mode analysis. Then, the initial UWB performance is achieved by introducing SRMMR to the basic Wilkinson power divider. Finally, a pair of parallel coupled lines is embedded into the SRMMR to achieve a desired notched band inside the UWB passband. The central frequency and the bandwidth of the notched band can be easily controlled by the electrical length and coupling coefficient of the coupled lines. To validate the design concept, a novel printed UWB power divider with notched band centered at frequencies of 5.8 GHz is designed and measured. The simulated and measured results indicate that it has a low insertion loss and good return loss performance at all the three ports, and a high isolation between the two output ports across the UWB bandwidth from 3.1 to 10.6 GHz with a small size of 0.46λg × 0.69λg ,w hereλg is the guided wavelength at 6.85 GHz.

In this paper, a novel printed microstrip-fed monopole ultra-wideband (UWB) antenna with triple-notched bands using triple-mode stepped impedance resonator (SIR) is presented. The proposed triple-mode SIR is found to have the advantages of introducing triple-notched bands and providing higher degree of freedom to adjust the resonant frequencies. By coupling the triple-mode SIR beside the microstrip feedline, band-rejected filtering properties around the 5.2 GHz WLAN band, the 6.8 GHz RFID band, and the X-band satellite communication band, are generated. To validate the design concept, a novel compact UWB antenna with three notched bands is designed and measured. Results indicate that the proposed compact antenna not only retains triple band-rejections capability but also owns omni directional radiation patterns across nearly whole operating bandwidth for UWB communications.

The intelligent household appliance wireless monitoring network can real-time monitor the apparent power and power factor of various household appliances in different indoor regions, and can realize the real-time monitoring on the household appliance working status and performance. The household appliance wireless monitoring network based on LEACH protocol is designed in the paper. Firstly, the basic idea of LEACH routing algorithm is proposed. Aiming at the node-distribution feature of intelligent home, the selection of cluster head in the routing algorithm and the data transmission method at the stable communication phase is modified. Moreover, the hardware circuit of power acquisition and power factor measurement is designed. The realization of wireless monitoring network based on CC2530 is described, each module and the whole system were conducted the on-line debugging. Finally, the system is proved to meet the practical requirement through the networking test.

A new microstrip ultra-wideband (UWB) bandpass fllter (BPF) with dual sharply rejected notched bands based on E-shaped resonator is proposed in this paper. The basic UWB BPF is designed using two microstrip interdigital coupled lines and one rectangular patch multiple-mode resonator (MMR). Then, to achieve dual band-notched performance, the proposed dual-mode E-shaped resonator is investigated and coupled to the rectangular patch multiple-mode resonator of the basic UWB BPF. To validate the design theory, a microstrip UWB BPF with two notch-bands centered at the frequencies of 5.8GHz and 8.0GHz, respectively, is designed and fabricated. Both simulation and experimental results are provided with good agreement.

A novel compact ultra-wideband (UWB) bandpass fllter (BPF) with triple sharply notched bands and wide upper stopband is proposed. The basic UWB BPF is composed of two microstrip interdigital coupled lines and one multiple-mode resonator (MMR). Then, to achieve triple band-notched performance, the proposed triple-mode stepped impedance resonator (TMSIR) is studied and coupled to the interdigital coupled lines of the basic UWB BPF. To validate the design theory, a microstrip UWB BPF with three notched bands respectively centered at 5.2GHz, 5.8GHz, and 6.8GHz is designed and fabricated. Both simulated and experimental results are provided with good agreement.

A miniaturized Gysel power divider/combiner (PDC) based on planar artiflcial transmission line (ATL) is presented in this paper. This planar ATL is composed of microstrip equivalent quasi- lumped elements and their discontinuities, and the ATL is capable of synthesizing microstrip line with various characteristic impedances and electrical lengths. For demonstration, the simulated and experimental results of proposed PDC @ 1GHz implemented on microstrip are given. Experimental results of the designed PDC agree well with the theoretical predictions. The proposed Gysel PDC circuit not only demonstrates low insertion loss at the fundamental frequency with compact size and high frequency suppression features, but also maintains Gysel PDC's high power-handling advantage. The occupied sizes of the proposed Gysel PDC are merely about 40% of the conventional Gysel PDC.

A novel super compact electromagnetic metamaterial transmission line (EM-MTM TL) is proposed in this paper by using the structure of symmetric double spiral lines (SDSLs). The investigation results indicate that the proposed EM-MTM TL not only has controllable resonant frequency, but also has very compact size, and the circuit area is only 8. 8m m× 7. 2m m (equal toλ0/32.16 × λ0/39.31, where λ0 is the free space wavelength at the resonant frequency) without the feed lines. Using the proposed structure, a 3-dB branch-line coupler and a 0-dB crossover operated at 0.86 GHz have been designed, fabricated and measured; the measured and simulated results are in good agreement. The two microwave devices realize 84.8% and 85.7% size reduction, respectively. Then, a compact Butler matrix is obtained by optimizing the combination of the branch-line couplers, 0 dB crossovers and 45-degree phase shifters. The measured and simulated results of the proposed Butler matrix agree well, showing that the proposed device operates at 0.86 GHz with very good electromagnetic performances. Moreover, the circuit area of the proposed Butler matrix is 109. 0m m× 89.3 mm, which realizes at least 80.9% size reduction in comparison with the conventional one (whose circuit area is at least 226. 2m m× 226.2 mm), and the miniaturization is considerable. Besides, these designed microwave devices, without any lumped elements, bonding wires, defected ground structure (DGS), and via-holes, are more suitable for modern wireless communication systems.

A novel approach to design microstrip ultra-wideband (UWB) bandpass fllter (BPF) using modifled genetic algorithm (MGA) is proposed in this paper. To achieve high e-ciency and accuracy, conventional GA is modifled. By improving the fltness evaluation, selection, crossover, and mutation, the two possible drawbacks of conventional GA, i.e., slow rate of convergence and local-best solution, are overcome. The modifled genetic algorithm is then applied to simultaneously search for the appropriate circuit topology and the corresponding electrical parameters with UWB characteristic. To demonstrate the efiectiveness of the novel approach, a new microstrip UWB BPF is designed and fabricated. Measurement results agree well with the design index and full-wave EM simulated results.