The Experts below are selected from a list of 218169 Experts worldwide ranked by ideXlab platform
Xia Huang - One of the best experts on this subject based on the ideXlab platform.
-
open external circuit for microbial fuel cell sensor to monitor the nitrate in aquatic environment
Biosensors and Bioelectronics, 2018Co-Authors: Donglin Wang, Yong Jiang, Peng Liang, Bo Miao, Panpan Liu, Wen Hao, Xia HuangAbstract:Abstract This study employed an open external circuit, rather than a closed circuit applied in previous studies, to operate an microbial fuel cell (MFC) sensor for real-time nitrate monitoring, and achieved surprisingly greater sensitivity (4.42 ± 0.3–6.66 ± 0.4 mV/(mg/L)) when the nitrate was at a Concentration of 10–40 mg/L, compared to that of the MFC sensor with a closed circuit (0.8 ± 0.05–1.6 ± 0.1 mV/(mg/L)). The MFC sensor operated in open circuit (O-MFC sensor) delivered much more stable performance than that operated in closed circuit (C-MFC sensor) when affected by organic matter (NaAc). The sensitivity of O-MFC sensor was twice that of C-MFC sensor at a low Background Concentration of organic matter. When organic matter reached a high Concentration, the sensitivity of O-MFC sensor remained at an acceptable level, while that of C-MFC sensor dropped to almost zero. Challenged by a combined shock of organic matter and nitrate, O-MFC sensor delivered evident electrical signals for nitrate warning, while C-MFC failed. Another novel feature of this study lies in a new mathematical model to examine the bioanode process of nitrate monitoring. It revealed that lower capacitance of the bioanode in O-MFC was the major contributor to the improved sensitivity of the device.
-
enhancing signal output and avoiding bod toxicity combined shock interference by operating a microbial fuel cell sensor with an optimized Background Concentration of organic matter
International Journal of Molecular Sciences, 2016Co-Authors: Yong Jiang, Peng Liang, Yanhong Bian, Bo Miao, Helan Zhang, Xia HuangAbstract:In the monitoring of pollutants in an aquatic environment, it is important to preserve water quality safety. Among the available analysis methods, the microbial fuel cell (MFC) sensor has recently been used as a sustainable and on-line electrochemical microbial biosensor for biochemical oxygen demand (BOD) and toxicity, respectively. However, the effect of the Background organic matter Concentration on toxicity monitoring when using an MFC sensor is not clear and there is no effective strategy available to avoid the signal interference by the combined shock of BOD and toxicity. Thus, the signal interference by the combined shock of BOD and toxicity was systematically studied in this experiment. The Background organic matter Concentration was optimized in this study and it should be fixed at a high level of oversaturation for maximizing the signal output when the current change (ΔI) is selected to correlate with the Concentration of a toxic agent. When the inhibition ratio (IR) is selected, on the other hand, it should be fixed as low as possible near the detection limit for maximizing the signal output. At least two MFC sensors operated with high and low organic matter Concentrations and a response chart generated from pre-experiment data were both required to make qualitative distinctions of the four types of combined shock caused by a sudden change in BOD and toxicity.
Lingxi Zhou - One of the best experts on this subject based on the ideXlab platform.
-
atmospheric co 2 at waliguan station in china transport climatology temporal patterns and source sink region representativeness
Atmospheric Environment, 2017Co-Authors: Siyang Cheng, Lingxi Zhou, Pieter P Tans, Andy JacobsonAbstract:Abstract In order to explore where the source and sink have the greatest impact on CO2 Background Concentration at Waliguan (WLG) station, a statistical method is here proposed to calculate the representative source-sink region. The key to this method is to find the best footprint threshold, and the study is carried out in four parts. Firstly, transport climatology, expressed by total monthly footprint, was simulated by FLEXPART on a 7-day time scale. Surface CO2 emissions in Eurasia frequently transported to WLG station. WLG station was mainly influenced by the westerlies in winter and partly controlled by the Southeast Asian monsoon in summer. Secondly, CO2 Concentrations, simulated by CT2015, were processed and analyzed through data quality control, screening, fitting and comparing. CO2 Concentrations displayed obvious seasonal variation, with the maximum and minimum Concentration appearing in April and August, respectively. The correlation of CO2 fitting Background Concentrations was R2 = 0.91 between simulation and observation. The temporal patterns were mainly correlated with CO2 exchange of biosphere-atmosphere, human activities and air transport. Thirdly, for the monthly CO2 fitting Background Concentrations from CT2015, a best footprint threshold was found based on correlation analysis and numerical iteration using the data of footprints and emissions. The grid cells where monthly footprints were greater than the best footprint threshold were the best threshold area corresponding to representative source-sink region. The representative source-sink region of maximum CO2 Concentration in April was primarily located in Qinghai province, but the minimum CO2 Concentration in August was mainly influenced by emissions in a wider region. Finally, we briefly presented the CO2 source-sink characteristics in the best threshold area. Generally, the best threshold area was a carbon sink. The major source and sink were relatively weak owing to less human activities and vegetation types in this high altitude area. CO2 Concentrations were more influenced by human activities when air mass passed through many urban areas in summer. Therefore, the combination of footprints and emissions is an effective approach for assessing the source-sink region representativeness of CO2 Background Concentration.
-
estimation of regional Background Concentration of co2 at lin an station in yangtze river delta china
Atmospheric Environment, 2014Co-Authors: Shuangxi Fang, Lingxi ZhouAbstract:A new method of extracting regional Background Concentration of CO2 in Yangtze River Delta was established based on the observations of both black carbon Concentration and meteorological parameters. The Concentrations of CO2 and black carbon were observed at Lin'an regional Background station from 2009 to 2011. The regional Background Concentration of CO2 in Yangtze River Delta was obtained by means of this new method, and the impact of human activities on CO2 Concentration in this area was also assessed. The results showed that the regional Background Concentration of CO2 extracted by this approach was comparable to the values obtained by R statistical filter method, and moreover this new method was better at picking up episodes heavily polluted by anthropogenic emissions. The annual regional average Background Concentration of CO2 in Yangtze River Delta from 2009 to 2011 was approximately 404.7 ± 8.2 ppm, 405.6 ± 5.3 ppm and 407.0 ± 5.3 ppm, respectively, much higher than global average value, indicating the distinct characteristic of this region. The anthropogenic emissions from Yangtze River Delta had significant influence on the Concentration of CO2, increasing the value roughly 9.1 ppm higher than the regional Background Concentration of this area.
Thomas F. Kuech - One of the best experts on this subject based on the ideXlab platform.
-
properties of bulk gaassbn gaas for multi junction solar cell application reduction of carbon Background Concentration
Journal of Crystal Growth, 2014Co-Authors: Taewan Kim, Thomas F. Kuech, Kamran Forghani, L J Mawst, Stephen Lalumondiere, Yongkun Sin, William T Lotshaw, Steven C MossAbstract:Abstract GaAsSbN epitaxial films on GaAs substrate grown by metalorganic vapor phase epitaxy (MOVPE) were investigated for integration into multi-junction solar cells. These films are nominally lattice-matched to the GaAs substrate with band gap energies ( E g ) in the 1–1.3 eV range. The high Background carbon Concentrations often observed in MOVPE-grown dilute-nitride materials are correlated with poor minority carrier lifetime and hence low photoluminescence (PL) intensity. In the MOVPE growth of dilute-nitride materials, this Background hole Concentration is quite sensitive to the selection of the gallium and antimony precursor, and the growth temperature. The lowest Background carbon Concentration is achieved in the dilute-nitride-antimonide alloys when triethyl gallium (TEGa) and Tris-dimethylamino antimony (TrisSb) sources are utilized. Based on GaAsSb/GaAs superlattice (SL) growth, higher-Sb incorporation efficiency occurs when TEGa and TrisSb are utilized compared to films grown using trimethyl gallium (TMGa) and trimethly antimony (TMSb) precursors. The Background hole Concentration of GaAsSbN ( E g ~1.23 eV) grown using TEGa and TrisSb is an order of magnitude lower than that observed when using TMGa and TMSb. Hall measurements indicate a Background hole Concentration of ~8.5×10 17 cm −3 ( E g ~1.23 eV) from the thermally annealed GaAsSbN films grown at 525 °C using TEGa and TrisSb. In addition, higher growth temperature 610 °C is utilized for further reducing the Background hole Concentration (3.2×10 17 cm −3 ). Carrier lifetimes of up to ~448 psec were obtained from thermally annealed GaAsSbN double hetero (DH) structure samples with energy bandgap ~1.25 eV.
-
1 25 ev gaassbn ge double junction solar cell grown by metalorganic vapor phase epitaxy for high efficiency multijunction solar cell application
IEEE Journal of Photovoltaics, 2014Co-Authors: Thomas F. KuechAbstract:Dilute-nitride-antimonide materials grown by metalorganic vapor phase epitaxy (MOVPE) with bandgap energies of 1.25 eV have been integrated into solar cell structures employing a Ge bottom cell on Ge substrate. Single homo- and heterojunction solar cells employing narrow bandgap GaAsSbN (E g ~ 1.25 eV) are grown normally lattice-matched on a GaAs substrate, using MOVPE. Homojunction solar cell structures were realized by employing GaAsSbN material with low carbon Background Concentration and Si doping to form a p/n junction. External quantum efficiency measurements in the range (870 nm-1000 nm) reveal that the efficiency of the homojunction solar cell is significantly improved over that of the heterojunction structure. The GaAsSbN homojunction cell was integrated with a Ge single-junction bottom cell on Ge substrate. Under AM1.5 direct illumination, the fabricated GaAsSbN (1.24 eV)/Ge double-junction solar cell with a 600-nm-thick GaAsSbN base layer exhibits Jsc, Voc, FF, and efficiency values of 11.59 mA/cm 2, 0.83 V, 72.58%, and 7% with anti-reflection coating (ARC), respectively.
Laibin Huang - One of the best experts on this subject based on the ideXlab platform.
-
distribution and contamination assessment of heavy metals in water and soils from the college town in the pearl river delta china
Clean-soil Air Water, 2012Co-Authors: Rong Xiao, Junjing Wang, Laibin HuangAbstract:The accumulation of heavy metals such as Cu, Zn, Pb, Cd, Cr, and Ni in water and soils in a new-built college town was investigated to demonstrate the effects of city construction on wetland ecosystem. Three sampling sites were chosen in wetland park (A), constructed wetland (B), and construction site (C), respectively. The results showed that the construction site C presented the highest accumulation levels of all six studied metals along soil profiles and hence had the highest eco-toxicity to environment. Sites A and B showed similar accumulation levels, whereas their Concentrations were significantly lower than those at site C though seriously high Cd were also found in soils from both sites A and B and dangerous Concentration of Pb in water was observed at site A based on several standards or Background Concentration values. However, when compared with other regions in Pearl River Delta, this college town could be counted as “clean island” which may be benefit from its isolate location away from urban center and the effective management to avoid pollution.
Yong Jiang - One of the best experts on this subject based on the ideXlab platform.
-
open external circuit for microbial fuel cell sensor to monitor the nitrate in aquatic environment
Biosensors and Bioelectronics, 2018Co-Authors: Donglin Wang, Yong Jiang, Peng Liang, Bo Miao, Panpan Liu, Wen Hao, Xia HuangAbstract:Abstract This study employed an open external circuit, rather than a closed circuit applied in previous studies, to operate an microbial fuel cell (MFC) sensor for real-time nitrate monitoring, and achieved surprisingly greater sensitivity (4.42 ± 0.3–6.66 ± 0.4 mV/(mg/L)) when the nitrate was at a Concentration of 10–40 mg/L, compared to that of the MFC sensor with a closed circuit (0.8 ± 0.05–1.6 ± 0.1 mV/(mg/L)). The MFC sensor operated in open circuit (O-MFC sensor) delivered much more stable performance than that operated in closed circuit (C-MFC sensor) when affected by organic matter (NaAc). The sensitivity of O-MFC sensor was twice that of C-MFC sensor at a low Background Concentration of organic matter. When organic matter reached a high Concentration, the sensitivity of O-MFC sensor remained at an acceptable level, while that of C-MFC sensor dropped to almost zero. Challenged by a combined shock of organic matter and nitrate, O-MFC sensor delivered evident electrical signals for nitrate warning, while C-MFC failed. Another novel feature of this study lies in a new mathematical model to examine the bioanode process of nitrate monitoring. It revealed that lower capacitance of the bioanode in O-MFC was the major contributor to the improved sensitivity of the device.
-
enhancing signal output and avoiding bod toxicity combined shock interference by operating a microbial fuel cell sensor with an optimized Background Concentration of organic matter
International Journal of Molecular Sciences, 2016Co-Authors: Yong Jiang, Peng Liang, Yanhong Bian, Bo Miao, Helan Zhang, Xia HuangAbstract:In the monitoring of pollutants in an aquatic environment, it is important to preserve water quality safety. Among the available analysis methods, the microbial fuel cell (MFC) sensor has recently been used as a sustainable and on-line electrochemical microbial biosensor for biochemical oxygen demand (BOD) and toxicity, respectively. However, the effect of the Background organic matter Concentration on toxicity monitoring when using an MFC sensor is not clear and there is no effective strategy available to avoid the signal interference by the combined shock of BOD and toxicity. Thus, the signal interference by the combined shock of BOD and toxicity was systematically studied in this experiment. The Background organic matter Concentration was optimized in this study and it should be fixed at a high level of oversaturation for maximizing the signal output when the current change (ΔI) is selected to correlate with the Concentration of a toxic agent. When the inhibition ratio (IR) is selected, on the other hand, it should be fixed as low as possible near the detection limit for maximizing the signal output. At least two MFC sensors operated with high and low organic matter Concentrations and a response chart generated from pre-experiment data were both required to make qualitative distinctions of the four types of combined shock caused by a sudden change in BOD and toxicity.
