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A novel circinal slot antenna with band-notched function suitable for UWB applications is presented and investigated in this paper. This antenna is designed to be used in frequency band of 3.1–10.6 GHz. Band-notched characteristic of antenna to reject the frequency band of 5.15–5.825 GHz, which is limited by IEEE 802.11a, is realized by parasitic inverted-U strip attached to the circinal slot plane. Experimental results show that the proposed antenna meets the requirement of wide-working bandwidth of 2.3–10.6 GHz with VSWR < 2, while avoiding the interference with the 5 GHz WLAN band. The parametric studies are performed numerically, and transfer functions of the antenna systems are given experimentally in this article. [ABSTRACT FROM AUTHOR]

A double-printed C-shape antenna for ultra-band application is proposed in this paper. With two C-shape dipole arms printed on the dielectric substrate and fed by a microstrip line, the antenna realized its ultra-wideband character by multistage impedance conversion. The impedance characteristic, radiation patterns and the transfer function are studied by both numerical simulation and experiment. The radiation patterns are approximately omni-directional with the VSWR < 2 from 3.1 to 10.6 GHz. Both transfer functions and group delay are smooth with linear phase which is valuable for the transmission of UWB signals. [ABSTRACT FROM AUTHOR]

The municipal solids waste (MSW) collected at Shanghai includes a high proportion of food waste, which is easily hydrolyzed to generate ammonia-nitrogen in leachate. This study investigated the efficiency of nitrogen removal from landfill leachate employing four different treatment processes. The simulated rainfall and direct leachate recycling produced strong leachate with high ammonia-nitrogen content, and resulted in the removal of only a small amount of nitrogen. Although pretreating the leachate using an aerobic reactor removed some nitrogen, most of which was transformed to biomass because of the high organic loading applied. Using the three-compartment system, which comprises a landfill column with fresh MSW, a column with well-decomposed refuse layer as the methane generator, and a nitrifier, the ammonia-nitrogen was converted into nitrogen gas and hence removed. Experimental results demonstrated the feasibility of adopting the three-compartment system for managing nitrogen in landfill leachate generated from high-nitrogen-content MSW. [ABSTRACT FROM AUTHOR]

The paper presents a method of designing a class of robust H [sub ∞] generator excitation controller in a power system. The proposed controller is utilized to damp inter-area oscillations and enhance power system stability. The robust controller design procedure for a linear composite system is presented in terms of positive definite solutions to modified algebraic inequalities. The resulting controller guarantees closed-loop stability and an H [sub ∞]-norm bound on disturbance attenuation. The effectiveness of the H ∞ controller is demonstrated through digital simulation studies on a two-machine system. The digital simulation studies are conducted using a PSCAD/EMTDC software package. The simulation results show that the controller contributes significantly to the damping of inter-area oscillations and the enhancement of power system stability during disturbances. [ABSTRACT FROM AUTHOR]

An epidemiological method, field-tested in Hunan, China, to identify residents potentially susceptible or insusceptible to endemic schistosomiasis japonica is described, as a prelude to selection of subjects for immunogenetic studies. After an initial cross-sectional survey on two islands (Qingshan and Niangashanpopulation 2990) in 1995-1996, an informative cohort (N = 249) was selected for treatment and 9-month follow-up to measure exposure and re-infection. Both the population prevalence (15.8%) and the geometric mean intensity of infection (26.2 eggs/g faeces) indicated that the islands were moderately endemic for schistosomiasis. Exposure measurements revealed a strong, positive, linear association (r = 0.70) between daily activity diaries and direct water-contact observation. Individuals identified as stool-positive for schistosomiasis had significantly more water contact than those who were egg-negative (P = 0.03). Almost all (93%) of the cohort had ultrasonographic evidence of periportal fibrosis before treatment but in only 1.2% was this fibrosis scored 1 in terms of the stages identified by the World Health Organization. At the follow-up it was possible to classify the 249 subjects into three, distinct, exposure-infection epidemiological groups. The first group (N = 20) was susceptible to re-infection and constituted 8% of the cohort. The second group (N = 61) was apparently insusceptible to re-infection despite the continuing high levels of exposure and included 24% of the cohort. The other 68% of the cohort (N = 168) remained uninfected but were at most only moderately exposed, or had a status indeterminate due to non-compliance. This epidemiological identification of susceptibles and insusceptibles for schistosomiasis japonica links field and ongoing laboratory studies aimed at characterising the genetic and immunological factors associated with resistance to re-infection and/or disease. [ABSTRACT FROM AUTHOR]