45 research outputs found

    Trapping Behaviors of Photogenerated Electrons on the (110), (101), and (221) Facets of SnO<sub>2</sub>: Experimental and DFT Investigations

    No full text
    Spatial separation of photogenerated charges between different crystal facets has been observed in some semiconductor photocatalysts; however, the charge separation mechanism is still ambiguous. As a characteristic parameter of crystal facet, surface energy may be a crucial factor to dictate the flow of photogenerated charges. In this work, the relationship between surface energy and the flow mode of photogenerated charges is investigated by using model photocatalysts, including lance-shaped SnO<sub>2</sub> particles and dodecahedral SnO<sub>2</sub> particles. The former are enclosed by two kinds of crystal facets with a big gap in surface energy, while the latter are composed of two types of crystal facets with nearly equal surface energy. However, the experimental results exhibit that the photogenerated electrons flow to all exposed crystal facets <i>randomly</i> in both two kinds of SnO<sub>2</sub> nanocrystals, which is opposite to what has been observed in extensively investigated semiconductor photocatalysts including TiO<sub>2</sub>, SrTiO<sub>3</sub>, BiVO<sub>4</sub>, BiOCl, and Cu<sub>2</sub>O. Our results disqualify surface energy as an appropriate descriptor of preferential charge flow. Furthermore, the experimental results are confirmed by trapping energies and work functions calculated with the first-principles methods, which are proved to be more relevant parameters for describing the charge flow direction. Additionally, the trapping sites on each crystal facet are determined by charge analysis

    Multi-Influences of Ionic Migration on Illumination-Dependent Electrical Performances of Inverted Perovskite Solar Cells

    No full text
    ZnO films are employed as the electron transport layers for perovskite solar cells. Such a device exhibits an ultralong time increase in <i>V</i><sub>oc</sub> (∼100 s) and <i>J</i><sub>sc</sub> (∼1000 s) and a weakening hysteresis under continuous illumination. Besides, a slow (∼20 s) <i>V</i><sub>oc</sub> decay when illumination is switched off is also observed. The electrical measurements performed under illumination and under voltage bias before being illuminated, suggest the influences of ionic accumulation/redistribution in causing above phenomena. Ionic accumulation happening in dark and ionic redistribution under illumination lead to band bending which affects the excitons separation and carrier extraction. These can account for the ultralong time increase in <i>V</i><sub>oc</sub> and <i>J</i><sub>sc</sub> as well as the slow <i>V</i><sub>oc</sub> decay. Also, the time-dependent photocurrent response under stepwise scan proves the presence of a capacitive effect in the device which can be dramatically reduced by the ionic redistribution under illumination. The ionic redistribution is also an important reason for the weakening hysteresis

    Confounding effects of hospital admissions for Upper Respiratory Infections (URI) on the associations between asthma hospital admissions in school-age children and ozone (top) and PM<sub>2.5</sub> (bottom).

    No full text
    <p>URI is included in the main model as log-transformed daily counts of all-age URI HA. Squares are point estimates for relative risks of asthma hospital admissions associated with increases in air pollutants. The dashed lines represent ±10% changes in the point estimates from the main model.</p

    Relative risks<sup>a</sup> of hospital admissions for asthma per 10 ppb increase in ozone concentrations or per 10 μg/m<sup>3</sup> increase in PM<sub>2.5</sub> concentrations in New York City, from 1999 to 2009.

    No full text
    <p>Relative risks<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180522#t002fn002" target="_blank"><sup>a</sup></a> of hospital admissions for asthma per 10 ppb increase in ozone concentrations or per 10 μg/m<sup>3</sup> increase in PM<sub>2.5</sub> concentrations in New York City, from 1999 to 2009.</p

    Relative risks<sup>a</sup> of hospital admissions for asthma per 10 ppb increase in ozone concentrations or per 10 μg/m3 increase in PM<sub>2.5</sub> concentrations at Lag 0–1 in New York City, stratified by socioeconomic status, during warm seasons from 2002 to 2006.

    No full text
    <p>Relative risks<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180522#t003fn002" target="_blank"><sup>a</sup></a> of hospital admissions for asthma per 10 ppb increase in ozone concentrations or per 10 μg/m3 increase in PM<sub>2.5</sub> concentrations at Lag 0–1 in New York City, stratified by socioeconomic status, during warm seasons from 2002 to 2006.</p

    Confounding effects of outdoor pollen on the associations between asthma hospital admissions in school-age children and ozone (top) and PM<sub>2.5</sub> (bottom).

    No full text
    <p>Squares are point estimates for relative risks of asthma hospital admissions associated with increases in air pollutants. The dashed lines represent ±10% changes in the point estimates from the main model.</p

    Daily hospital admissions for asthma and upper respiratory infections, air pollutants, outdoor pollen, and temperature in New York City, from 1999 to 2009.

    No full text
    <p>Daily hospital admissions for asthma and upper respiratory infections, air pollutants, outdoor pollen, and temperature in New York City, from 1999 to 2009.</p

    Additional file 1: Fig. S1. of Ambient ozone and asthma hospital admissions in Texas: a time-series analysis

    No full text
    Histograms of pollen counts. A. Original data. B. Log-transformed data. Fig. S2 Histograms of aeroallergen counts. A. Original data. B. Log-transformed data. Table S1 Descriptive statistics of asthma HAs, ambient O3, pollen, and meteorological factors in Dallas, Houston, and Austin, Texas, from 2003 to 2011. Table S2 Associationsa between asthma HAs and ambient O3 concentrations in Dallas, Houston, and Austin, Texas, from 2003 to 2011. Table S3 Associationsa between asthma HAs and ambient O3 concentrations, with adjustment for pollen, in Dallas, Houston, and Austin, Texas, from 2003 to 2011. Table S4 Associations between asthma HAs and ambient O3 concentrations, with adjustment for pollen using alternative dataa for Dallas. Table S5 Associations between asthma HAs and ambient O3 concentrations, with adjustments for pollen and respiratory infection HAs, in Dallas, Houston, and Austin, Texas, from 2003 to 2011. Table S6 Results of asthma HAs per 10 ppb increase in O3 concentrations, with adjustment for aeroallergen, in Dallas and Houston, Texas, from 2003 to 2011. Table S7 Sensitivity analyses with different specifications of temperature and dew point . Table S8 Sensitivity analysesa with different specifications of temporal trend. Table S9 Sensitivity analysesa with O3 concentrations at lag −1 day. Table S10 Associationsa between acute appendicitis HAs and ambient O3 in Dallas, Houston, and Austin, Texas, from 2003 to 2011. (XLSX 95 kb

    Characterization of single mutant of <i>Osbhlh067</i>, <i>Osbhlh068</i>, and <i>Osbhlh069</i>.

    No full text
    (A) and (B) Comparison of the gross plant (A) and panicle (B) among WT, Osbhlh067, Osbhlh068, and Osbhlh069 during reproductive growth. Bars in (A) and (B) = 20 cm and 4 cm, respectively. (C) to (H) Quantification of the number of tillers (C), PBs (D), SBs (E), SPBs (F), SSBs (G), and total spikelets (H) among WT, Osbhlh067, Osbhlh068, and Osbhlh069. Values in (C) to (H) are shown as means ± SEM from 12 replicates. Different letters denote significant differences ranked by the Dunnett’s test (one-way analysis of variance, P  (TIF)</p

    Expression profiles and subcellular localization of OsbHLH067/068/069.

    No full text
    (A) to (C) Expression levels of OsbHLH069 (A), OsbHLH067 (B), and OsbHLH068 (C) in various organs, including R (root), C (culm), L (leaf), LS (leaf sheath), and P (panicle UBQ gene acted as a control. Values represent means ± SEM from nine replicates. (D) Subcellular localization of OsbHLH069, OsbHLH067, and OsbHLH068 in rice protoplasts. The LAX1-RFP vector was used as a nuclear marker. The 35S-GFP vector served as a control. Bars = 10 μm. (TIF)</p
    corecore