Composite supports CeO2-ZrO2-Al2O3（CZA） and CeO2-ZrO2-Al2O3-La2O3（CZALa） were prepared by co-precipitation method. Palladium catalysts were prepared by impregnation and their purification ability for CH4, CO and N...Composite supports CeO2-ZrO2-Al2O3（CZA） and CeO2-ZrO2-Al2O3-La2O3（CZALa） were prepared by co-precipitation method. Palladium catalysts were prepared by impregnation and their purification ability for CH4, CO and NOx in the mixture gas simulated the exhaust from natural gas vehicles （NGVs） operated under stoichiometric condition was investigated. The effect of La2O3 on the physicochemical properties of supports and catalysts was characterized by various techniques. The characterizations with X-ray diffraction （XRD） and Raman spectroscopy revealed that the doping of La2O3 restrained effectively the sintering of crystallite particles, maintained the crystallite particles in nanoscale and stabilized the crystal phase after calcination at 1000 ℃. The results of N2-adsorption, H2-temperatnre-programmed reduction （H2-TPR） and oxygen storage capacity （OSC） measurements indicated that La2O3 improved the textural properties, reducibility and OSC of composite supports. Activity testing results showed that the catalysts exhibit excellent activities for the simultaneous removal of methane, CO and NOx in the simulated exhaust gas. The catalysts supported on CZALa showed remarkable thermal stability and catalytic activity for the three pollutants, especially for NOx. The prepared palladium catalysts have high ability to remove NOx, CH4 and CO, and they can be used as excellent catalysts for the purification of exhaust from NGVs operated under stoichiometric condition. The catalysts reported in this work also have significant potential in industrial application because of their high performance and low cost.展开更多
Pyrethroids,organophosphorus pesticides and fipronil have been listed as priority chemicals in human biomonitoring studies because of their wide use and potential health effects in humans.The determination of 13 pesti...Pyrethroids,organophosphorus pesticides and fipronil have been listed as priority chemicals in human biomonitoring studies because of their wide use and potential health effects in humans.The determination of 13 pesticides,including pyrethroids(deltamethrin,cypermethrin,permethrin,cyfluthrin,bifenthrin),organophosphorus(chlorpyrifos,chlorpyrifosmethyl,and malathion),fipronil,neonicotinoids(imidacloprid,acetamiprid and thiacloprid)and triazole(prothioconazole),together with 13 corresponding metabolites in human urine samples was achieved by solid-phase extraction and analysis by liquid chromatography coupled to tandem mass spectrometry.All targeted compounds,except malathion dicarboxylic acid,were measured with a mean within-accuracy(n=5)of 71%–114%(RSD:1%–14%)and between-run(n=15)accuracy of 80%–118%(RSD:2%–14%).Limits of quantitation of the targeted analytes ranged from 0.1 to 16 pg/m L.The detection result of urine samples from 25 volunteers indicated that the detection frequencies of 3,5,6-trichloro-2-pyridinol(median:448 pg/m L),6-chloropyridine-3-carboxylic acid(median:193 pg/m L),2-methyl-3-phenylbenzoic acid(median:181 pg/m L),3-phenoxybenzoic acid(median:99 pg/m L),2-isopropyl-6-methyl-4-pyrimidinol(median:77 pg/m L),cyfluthrin(median:59 pg/m L),cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid(cis-DCCA,median:53 pg/m L),trans-DCCA(median:25 pg/m L),prothioconazole(median:21 pg/m L),imidacloprid(median:7 pg/m L),and prothioconazole-desthio(median:1 pg/m L)were>50%.The obtained results show that the validated method is suitable for the human biomonitoring of these currentuse pesticides and their metabolites.展开更多
The multi-antenna synchronized global navi- gation satellite system receiver is a high precision, low cost, and widely used emerging receiver. Using this type of receiver, the satellite and receiver clock errors can b...The multi-antenna synchronized global navi- gation satellite system receiver is a high precision, low cost, and widely used emerging receiver. Using this type of receiver, the satellite and receiver clock errors can be eliminated simultaneously by forming between antenna single-differences, which is equivalent to the conventional double-difference model. However, current multi-antenna synchronized global navigation satellite system receiver products have not fully realized their potential to achieve better accuracy, efficiency, and broader applications. This paper introduces the conceptual design and derivable products of multi-antenna synchronized global navigation satellite system receivers involving the aspects of attitude determination, multipath effect mitigation, phase center variation correction, and ground-based carrier phase wind- up calibration. Through case studies, the advantages of multi-antenna synchronized global navigation satellite system receivers in high-precision positioning applications are demonstrated.展开更多
基金supported by the National Natural Science Foundation of China (No. 20773090, 20803049)the National High Technology Researchand Development Program of China (863 Program, No. 2006AA06Z347)the Specialized Research Fund for the Doctoral Program of Higher Education(20070610026)
文摘Composite supports CeO2-ZrO2-Al2O3（CZA） and CeO2-ZrO2-Al2O3-La2O3（CZALa） were prepared by co-precipitation method. Palladium catalysts were prepared by impregnation and their purification ability for CH4, CO and NOx in the mixture gas simulated the exhaust from natural gas vehicles （NGVs） operated under stoichiometric condition was investigated. The effect of La2O3 on the physicochemical properties of supports and catalysts was characterized by various techniques. The characterizations with X-ray diffraction （XRD） and Raman spectroscopy revealed that the doping of La2O3 restrained effectively the sintering of crystallite particles, maintained the crystallite particles in nanoscale and stabilized the crystal phase after calcination at 1000 ℃. The results of N2-adsorption, H2-temperatnre-programmed reduction （H2-TPR） and oxygen storage capacity （OSC） measurements indicated that La2O3 improved the textural properties, reducibility and OSC of composite supports. Activity testing results showed that the catalysts exhibit excellent activities for the simultaneous removal of methane, CO and NOx in the simulated exhaust gas. The catalysts supported on CZALa showed remarkable thermal stability and catalytic activity for the three pollutants, especially for NOx. The prepared palladium catalysts have high ability to remove NOx, CH4 and CO, and they can be used as excellent catalysts for the purification of exhaust from NGVs operated under stoichiometric condition. The catalysts reported in this work also have significant potential in industrial application because of their high performance and low cost.
基金supported by the China Scholarship Council oversea Ph D study program(No.201906850003)by the Exposome center of Excellence of the University of Antwerp(BOF grant,Antigoon ID no.41222)。
文摘Pyrethroids,organophosphorus pesticides and fipronil have been listed as priority chemicals in human biomonitoring studies because of their wide use and potential health effects in humans.The determination of 13 pesticides,including pyrethroids(deltamethrin,cypermethrin,permethrin,cyfluthrin,bifenthrin),organophosphorus(chlorpyrifos,chlorpyrifosmethyl,and malathion),fipronil,neonicotinoids(imidacloprid,acetamiprid and thiacloprid)and triazole(prothioconazole),together with 13 corresponding metabolites in human urine samples was achieved by solid-phase extraction and analysis by liquid chromatography coupled to tandem mass spectrometry.All targeted compounds,except malathion dicarboxylic acid,were measured with a mean within-accuracy(n=5)of 71%–114%(RSD:1%–14%)and between-run(n=15)accuracy of 80%–118%(RSD:2%–14%).Limits of quantitation of the targeted analytes ranged from 0.1 to 16 pg/m L.The detection result of urine samples from 25 volunteers indicated that the detection frequencies of 3,5,6-trichloro-2-pyridinol(median:448 pg/m L),6-chloropyridine-3-carboxylic acid(median:193 pg/m L),2-methyl-3-phenylbenzoic acid(median:181 pg/m L),3-phenoxybenzoic acid(median:99 pg/m L),2-isopropyl-6-methyl-4-pyrimidinol(median:77 pg/m L),cyfluthrin(median:59 pg/m L),cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid(cis-DCCA,median:53 pg/m L),trans-DCCA(median:25 pg/m L),prothioconazole(median:21 pg/m L),imidacloprid(median:7 pg/m L),and prothioconazole-desthio(median:1 pg/m L)were>50%.The obtained results show that the validated method is suitable for the human biomonitoring of these currentuse pesticides and their metabolites.
基金Acknowledgements This work is sponsored by the National Natural Science Foundation of China （Grant Nos. 61372086, 11373017, 41201380, 41171327, and 41201379）, Foundation of Science and Technology Commission of Shanghai （Nos. 13511500300 and 15511101602）, Open Research Funding of the Key Laboratory of Embedded System and Service Computing （No. 48505280） and Open Research Funding Program of KLGIS （No. KLGIS2014A02）.
文摘The multi-antenna synchronized global navi- gation satellite system receiver is a high precision, low cost, and widely used emerging receiver. Using this type of receiver, the satellite and receiver clock errors can be eliminated simultaneously by forming between antenna single-differences, which is equivalent to the conventional double-difference model. However, current multi-antenna synchronized global navigation satellite system receiver products have not fully realized their potential to achieve better accuracy, efficiency, and broader applications. This paper introduces the conceptual design and derivable products of multi-antenna synchronized global navigation satellite system receivers involving the aspects of attitude determination, multipath effect mitigation, phase center variation correction, and ground-based carrier phase wind- up calibration. Through case studies, the advantages of multi-antenna synchronized global navigation satellite system receivers in high-precision positioning applications are demonstrated.
