The degradation mechanism of an Sn_4P_3 electrode as Na-ion battery anode was investigated by using a transmission electron microscopic observation. At the first desodiation, we confirmed that Sn nanoparticles with 6 ...The degradation mechanism of an Sn_4P_3 electrode as Na-ion battery anode was investigated by using a transmission electron microscopic observation. At the first desodiation, we confirmed that Sn nanoparticles with 6 nm in size were dispersed in an amorphous-like P matrix.Compared to this, we observed aggregated Sn particles with sizes exceeding 50 nm after the drastic capacity fading. The capacity fading mechanism was for the first time confirmed to be Sn aggregation. To improve the capacity decay, we carried out the two kinds of chargeàdischarge cycling tests under the reduced volume changes of Sn particles and P matrix by limiting desodiation reactions of Nae Sn and Na3P, respectively. The Sn_4P_3 electrode exhibited an excellent cyclability with the discharge capacity of 500 mA hg^(-1) for 420 cycles under the limited desodiation, whereas the capacity decay was accelerated under the limited sodiation. The results suggest that the Sn aggregation can be improved by the reduced volume change of the P matrix, and that it is very effective for improving anode performance of Sn_4P_3 electrode.展开更多
The linearity, stability, accuracy and inter-day precisions of the assay method were evaluated in water, soil and rhizomes and leaves of Hedychium coronarium of the Zingiberaceae family. Mato Grosso do Sul is a predom...The linearity, stability, accuracy and inter-day precisions of the assay method were evaluated in water, soil and rhizomes and leaves of Hedychium coronarium of the Zingiberaceae family. Mato Grosso do Sul is a predominantly agricultural state in Brazil and has many rivers and permanent and seasonal lakes, in which the Hedychium coronarium, an aquatic plant, is found the swampy environments. The prepared samples were analyzed quantitatively by High Performance Liquid Chromatography with PDA and UV detection for the presence of thiamethoxam. The thiamethoxam was recovered from these samples at rates ranging from 81.16% - 99.93%. The coefficient of variation in the quantitative analysis of the thiamethoxam was under 5%. The linearity of the method was determined by linear regression. The analysis of the samples spiked with known amounts of analyte demonstrated that the response was proportional to the concentrations of the samples with determination coefficients of r2 = 0.9992 (water and soil) and r2 = 0.9990 (leaves and rhizomes) for the linear range of the analytical calibration curves of the samples. The detection limit was 0.36 μg.L-1 and quantification limit was 1.2 μg.L-1 for thiamethoxam. The method was considered sensitive for quantification of the thiamethoxam in water, soil and rhizomes and leaves of Hedychium coronarium.展开更多
The linearity, stability, accuracy and inter-day precisions of the assay method were evaluated in methanolic aerial-part extracts of Paepalanthus giganteus and Syngontnhus nitens from the Eriocaulaceae family. Their s...The linearity, stability, accuracy and inter-day precisions of the assay method were evaluated in methanolic aerial-part extracts of Paepalanthus giganteus and Syngontnhus nitens from the Eriocaulaceae family. Their small capitulae hinder morphological analysis, and thus complicate taxonomic studies of these species, which present anti-ulcer, antimutagenic and antioxidant activities. Taxonomic studies of these plants revealed that the Paepalanthus genus presents flavonols and naphthopyranones while the Syngontnhus genus has flavone and xanthone as majority compounds. The prepared samples were analyzed quantitatively by High Performance Liquid Chromatography with PDA detection for the presence of quercetin, luteolin, 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone and paepalantine. The substances were recovered from these samples at rates from 98.01 to 99.99%. The coefficient of variation in the quantitative analysis of the sample com- pounds was under 5%. The linearity of the method was determined by linear regression. The analysis of the samples spiked with known amounts of analyte demonstrated that the response was proportional to the concentrations of the sam- ples with re-spective determination coefficients of r2 = 0.9999 (luteolin and 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone) and r2 = 0.9998 (quercetin and paepalantine) for the linear range of the analytical calibration curves of the samples. The detection limits were 0.07 μg?mL–1 for quercetin and luteolin, 0.06 μg?mL–1 for 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone and 0.10 μg?mL–1 for paepalantine. The quantification limits were 0.23 μg?mL–1 for quercetin and luteolin, 0.20 μg?mL–1 for 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone and 0.33 μg?mL–1 for paepalantine by LC. The method was considered sen- sitive for quantification of the quercetin, luteolin, 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone and paepalantine in plant samples.展开更多
基金partially supported by Advanced Low Carbon Technology Research and Development Program(ALCA,16200610802)Joint Usage/Research Program on Zero-Emission Energy Research,Institute for Applied Ecology,Kyoto University(ZE29A-14,ZE30A-05,ZE30A-06)+1 种基金Japan Society for the Promotion of Science(JSPS)KAKENHI(Grant Number 17H03128,17K17888,16K05954)supported by "Advanced Characterization Nanotechnology Platform,Nanotechnology Platform Program of the Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan" at the Research Center for Ultra-High Voltage Electron Microscopy in Osaka University(A-17-OS-0020,A-18-S-0002)
文摘The degradation mechanism of an Sn_4P_3 electrode as Na-ion battery anode was investigated by using a transmission electron microscopic observation. At the first desodiation, we confirmed that Sn nanoparticles with 6 nm in size were dispersed in an amorphous-like P matrix.Compared to this, we observed aggregated Sn particles with sizes exceeding 50 nm after the drastic capacity fading. The capacity fading mechanism was for the first time confirmed to be Sn aggregation. To improve the capacity decay, we carried out the two kinds of chargeàdischarge cycling tests under the reduced volume changes of Sn particles and P matrix by limiting desodiation reactions of Nae Sn and Na3P, respectively. The Sn_4P_3 electrode exhibited an excellent cyclability with the discharge capacity of 500 mA hg^(-1) for 420 cycles under the limited desodiation, whereas the capacity decay was accelerated under the limited sodiation. The results suggest that the Sn aggregation can be improved by the reduced volume change of the P matrix, and that it is very effective for improving anode performance of Sn_4P_3 electrode.
文摘The linearity, stability, accuracy and inter-day precisions of the assay method were evaluated in water, soil and rhizomes and leaves of Hedychium coronarium of the Zingiberaceae family. Mato Grosso do Sul is a predominantly agricultural state in Brazil and has many rivers and permanent and seasonal lakes, in which the Hedychium coronarium, an aquatic plant, is found the swampy environments. The prepared samples were analyzed quantitatively by High Performance Liquid Chromatography with PDA and UV detection for the presence of thiamethoxam. The thiamethoxam was recovered from these samples at rates ranging from 81.16% - 99.93%. The coefficient of variation in the quantitative analysis of the thiamethoxam was under 5%. The linearity of the method was determined by linear regression. The analysis of the samples spiked with known amounts of analyte demonstrated that the response was proportional to the concentrations of the samples with determination coefficients of r2 = 0.9992 (water and soil) and r2 = 0.9990 (leaves and rhizomes) for the linear range of the analytical calibration curves of the samples. The detection limit was 0.36 μg.L-1 and quantification limit was 1.2 μg.L-1 for thiamethoxam. The method was considered sensitive for quantification of the thiamethoxam in water, soil and rhizomes and leaves of Hedychium coronarium.
基金the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo(FAPESP),for fundingthe Conselho Nacional de Desenvolvimento Científico e Tecnologico(CNPq),for grants to L.C.Santos.
文摘The linearity, stability, accuracy and inter-day precisions of the assay method were evaluated in methanolic aerial-part extracts of Paepalanthus giganteus and Syngontnhus nitens from the Eriocaulaceae family. Their small capitulae hinder morphological analysis, and thus complicate taxonomic studies of these species, which present anti-ulcer, antimutagenic and antioxidant activities. Taxonomic studies of these plants revealed that the Paepalanthus genus presents flavonols and naphthopyranones while the Syngontnhus genus has flavone and xanthone as majority compounds. The prepared samples were analyzed quantitatively by High Performance Liquid Chromatography with PDA detection for the presence of quercetin, luteolin, 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone and paepalantine. The substances were recovered from these samples at rates from 98.01 to 99.99%. The coefficient of variation in the quantitative analysis of the sample com- pounds was under 5%. The linearity of the method was determined by linear regression. The analysis of the samples spiked with known amounts of analyte demonstrated that the response was proportional to the concentrations of the sam- ples with re-spective determination coefficients of r2 = 0.9999 (luteolin and 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone) and r2 = 0.9998 (quercetin and paepalantine) for the linear range of the analytical calibration curves of the samples. The detection limits were 0.07 μg?mL–1 for quercetin and luteolin, 0.06 μg?mL–1 for 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone and 0.10 μg?mL–1 for paepalantine. The quantification limits were 0.23 μg?mL–1 for quercetin and luteolin, 0.20 μg?mL–1 for 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone and 0.33 μg?mL–1 for paepalantine by LC. The method was considered sen- sitive for quantification of the quercetin, luteolin, 3,6-dimethoxy-1,5,7-tri-hydroxyxanthone and paepalantine in plant samples.
