Subwavelength plasmonic waveguides are the most promising candidates for developing planar photonic circuitry platforms. In this study a subwavelength metallic ridge waveguide is numerically and experimentally investigated. Differing from previous plasmonic waveguides, the metallic strip of the subwavelength ridge waveguide is placed on a thick metal film. It is found that the surface-plasmon-polariton (SPP) waveguide modes result from the coupling of the corner modes in the two ridge corners. The bottom metal film has a great influence on the SPP modes, and nearly all the evanescent fields of the SPP modes are tightly confined outside the ridge waveguide. Simulations show that 50% of the total power flow in the SPP mode can be confined outside the ridge waveguide with an area of only about λ 2/20. The propagation length is still about 10 times the plasmon wavelength. Through comparison with a metallic strip placed directly on the dielectric substrate, the proposed ridge waveguide exhibits a much higher sensing performance. This plasmonic ridge waveguide with deep-subwavelength outside-field confinements is of significance in a range of nano-optics applications, especially in nanosensing.
The unique nature of built-in electric field induced positive/negative charge pairs of polar semiconductor heterojunction structure has led to a more realistic device model for hexagonal III-nitride HEMT. In this modeling approach, the distribution of charge carriers is dictated by the electrostatic potential profile instead of Femi statistics. The proposed device model is found suitable to explain peculiar properties of GaN HEMT structures, including: (1) Discrepancy in measured conventional linear transmission line model (LTLM) sheet resistance and contactless sheet resistance of GaN HEMT with thin barrier layer. (2) Below bandgap radiation from forward biased Nickel Schottky barrier diode on GaN HEMT structure. (3) GaN HEMT barrier layer doping has negligible effect on transistor channel sheet charge density. (C) 2016 AIP Publishing LLC.
The community structure of ammonia-oxidizing microorganisms is sensitive to various environmental factors, including pollutions. In this study, real-time PCR and 454 pyrosequencing were adopted to investigate the population and diversity of ammonia-oxidizing archaea (AOA) and bacteria (AOB) temporally and spatially in the sediments of an industrial effluent receiving area in the Qiantang River’s estuary, Hangzhou Bay. The abundances of AOA and AOB amoA genes fluctuated in 105–107 gene copies per gram of sediment; the ratio of AOA amoA/AOB amoA ranged in 0.39–5.52. The AOA amoA/archaeal 16S rRNA, AOB amoA/bacterial 16S rRNA, and AOA amoA/AOB amoA were found to positively correlate with NH4+-N concentration of the seawater. Nitrosopumilus cluster and Nitrosomonas-like cluster were the dominant AOA and AOB, respectively. The community structures of both AOA and AOB in the sediments exhibited significant seasonal differences rather than spatial changes in the effluent receiving area. The phylogenetic distribution of AOB in this area was consistent with the wastewater treatment plants (WWTPs) discharging the effluent but differed from the Qiantang River and other estuaries, which might be an outcome of long-term effluent discharge.
Health risk of residents dwelling around e-waste recycling zones has been a global concern, but has not been adequately examined. The present study was intended to evaluate the potential health risk of residents through inhalation exposure to size-fractionated particle-bound heavy metals in a typical e waste recycling zone, South China. Anthropogenic metals (Zn, Se, Pb, Sb, As, and Cd) were predominantly enriched in fine particles (D-P < 1.8 mu m), whereas the crustal elements,(Ti, Fe, and Co) tended to accumulate in coarse particles (D-p > 1.8 mu m). Although the daily inhalation intakes of the target metals were significantly lower than those through food consumption and ingestion of house dust, the hazard quotients of total metals for adults (95% CI: 1.0-5.5) and children (95% CI: 3.0-17) were greater than 1. Moreover, the incremental lifetime cancer risks of five carcinogenic metals (Cr, Co, Ni, As, and Cd) for adults and children were 1.3 x 10(-3) (95% CI: 4.1 x 10(-4)-3.0 x 10(-3)) and 3.9 x 10(-3) (95% CI: 1.3 x 10(-3)-8.6 x 10(-3)), respectively, substantially higher than the acceptable cancer risk range of 10(-6)-10(-4). All these findings suggested that health risks were high for local residents dwelling around the e-waste recycling zone through inhalation exposure to particle-bound heavy metals, for both adults and children. (C) 2016 Elsevier B.V. All rights reserved.
This paper intends to learn from international experiences in order to facilitating China's ongoing regional university transformation with an ultimate goal to enhance the role of university in regional economic development and innovation. In so doing, this paper compares major models of universities of applied sciences (UAS) around the world from the perspective of the Triple Helix Model with an emphasis on the nature of university-industry relation implied by each model, and then exploring their relevance for China's UASs transformation. It is concluded that the Finnish model is the most relevant to China. By comparing the Finnish and Chinese practices, a number of recommendations are solicited to Chinese policy-makers.
BACKGROUND: The increasing use of silver nanoparticles (AgNPs) in consumer products is concerning. We examined the potential toxic effects when inhaled in Brown-Norway (BN) rats with a pre-inflammatory state compared to Sprague-Dawley (SD) rats. METHODS: We determined the effect of AgNPs generated from a spark generator (mass concentration: 600-800 mug/mm(3); mean diameter: 13-16 nm; total lung doses: 8 [Low] and 26-28 [High] mug) inhaled by the nasal route in both rat strains. Rats were sacrificed at day 1 and day 7 after exposure and measurement of lung function. RESULTS: In both strains, there was an increase in neutrophils in bronchoalveolar lavage (BAL) fluid at 24 h at the high dose, with concomitant eosinophilia in BN rats. While BAL inflammatory cells were mostly normalised by Day 7, lung inflammation scores remained increased although not the tissue eosinophil scores. Total protein levels were elevated at both lung doses in both strains. There was an increase in BAL IL-1beta, KC, IL-17, CCL2 and CCL3 levels in both strains at Day 1, mostly at high dose. Phospholipid levels were increased at the high dose in SD rats at Day 1 and 7, while in BN rats, this was only seen at Day 1; surfactant protein D levels decreased at day 7 at the high dose in SD rats, but was increased at Day 1 at the low dose in BN rats. There was a transient increase in central airway resistance and in tissue elastance in BN rats at Day 1 but not in SD rats. Positive silver-staining was seen particularly in lung tissue macrophages in a dose and time-dependent response in both strains, maximal by day 7. Lung silver levels were relatively higher in BN rat and present at day 7 in both strains. CONCLUSIONS: Presence of cellular inflammation and increasing silver-positive macrophages in lungs at day 7, associated with significant levels of lung silver indicate that lung toxicity is persistent even with the absence of airway luminal inflammation at that time-point. The higher levels and persistence of lung silver in BN rats may be due to the pre-existing inflammatory state of the lungs.
