This paper analyses the principle of wicking effect of the polypropylene filament yarn. By means of theoretical and experimental analysis, some factors affecting the moisture transmission of the pure polypropylene kni...This paper analyses the principle of wicking effect of the polypropylene filament yarn. By means of theoretical and experimental analysis, some factors affecting the moisture transmission of the pure polypropylene knitted fabrics are discussed.展开更多
Environmental stability is a major bottleneck of perovskite solar cells.Only a handful of studies are investigating the effect of moisture on the structural degradation of the absorber.They mostly rely on ex situ expe...Environmental stability is a major bottleneck of perovskite solar cells.Only a handful of studies are investigating the effect of moisture on the structural degradation of the absorber.They mostly rely on ex situ experiments and on completely degraded samples,which restrict the assessment on initial and final stage.By combining in situ X-ray diffraction under controlled 85%relative humidity,and live observations of the water-induced degradation using liquid-cell transmission electron microscopy,we reveal two competitive degradation paths leading on one hand to the decomposition of state-of-theart mixed cation/anion(Cs_(0.05)(MA_(0.17)FA_(0.83))_(0.95)Pb(Br_(0.17)I_(0.83))_(3)(CsMAFA)into PbI_(2) through a dissolution/recrystallization mechanism and,on the other hand,to a non-equilibrium phase segregation leading to CsPb_(2)Br_(5) and a Cesium-poor/iodide-rich Cs_(0.05)-x(MA_(0.17)FA_(0.83))_(0.95)Pb(Br_(0.17-2y)I_(0.83)+2y)_(3) perovskite.This degradation mechanism is corroborated at atomic-scale resolution through solid-state ^(1)H and ^(133)Cs NMR analysis.Exposure to moisture leads to a film containing important heterogeneities in terms of morphology,photoluminescence intensities,and lifetimes.Our results provide new insights and consensus that complex perovskite compositions,though very performant as champion devices,are comparatively metastable,a trait that limits the chances to achieve long-term stability.展开更多
Background Transparent dressings are commonly used to cover central venous catheter sites. However, it has been suggested that they might not allow adequate moisture vapor transmission, resulting in local moistness th...Background Transparent dressings are commonly used to cover central venous catheter sites. However, it has been suggested that they might not allow adequate moisture vapor transmission, resulting in local moistness that promotes bacterial growth. We compared the moisture vapor transmission rates （MVTRs） of different, currently used transparent and traditional gauze dressings. We aimed to determine the MVTRs at different temperatures and humidities. Methods The dressings were used to seal 50-ml plastic centrifuge tubes containing 20 ml deionized water： Tubes in group 1 were covered with 12 layers of ordinary gauze, group 2 with IV3000, group 3 with OPSITE FLEXlGRID, group 4 with 3M HP Tegaderm, and group 5 with 3M Tegaderm. The tubes were placed upright in an artificial climate cabinet, so that the dressings were not touching the water, in order to simulate the conditions of medical dressings in contact with the skin. The average MVTRs were determined under different conditions. MVTRs were also determined with tubes from groups 2-5 laid on their sides, allowing the dressings to touch the water, so simulating contact of the dressings with sweating skin, or wounded skin with exudates. We also calculated the dressings＇ self-reactive abilities by comparing their MVTRs in contact with the water surface with those when not in contact with the water surface. Results Group 1 demonstrated the highest MVTR, followed by groups 2, 4, 3 and 5 under conditions simulating contact of the dressings with normal skin at the following temperatures and humidities： 20℃/30%, 20℃/60%, 20℃/90%, 37℃/30%, 37℃/60% and 37℃/90%. When the relative humidity （RH） increased, the MVTRs decreased. The MVTRs differed significantly among different dressings and RHs： At high temperature （37℃） and high humidity （90%）, the MVTR of the transparent dressings in group 2 was higher than that of group 1 （P 〈0.01）. The reactive MVTR was highest in group 2 （10.2-16.3 times 〉MVTR） while that of group 4 was second highest （2.6-9.6 times 〉MVTR）. Conclusions RH and temperature had significant effects on the MVTRs of different dressings. The IV3000 transparent dressing used in group 2 was as effective as ordinary gauze. These results suggest that increased infection rates due to low MVTRs might not be a problem. The clinical implications of these observations for catheter-related infections need to be further investigated in multicenter studies.展开更多
文摘This paper analyses the principle of wicking effect of the polypropylene filament yarn. By means of theoretical and experimental analysis, some factors affecting the moisture transmission of the pure polypropylene knitted fabrics are discussed.
基金financial support from Region Hauts-de-France,FEDER,and Electricité de France(EDF)through PEROVSTAB programfinancial support from the IR-RMN-THC FR-3050 CNRS France for conducting solid-state NMR measurements.P.R.and G.N.M.R+1 种基金financial support from University of Lille and région Hauts-de-France.F.S“IMPRESSIVE”project which received funding from the European Union’s Horizon 2020 Research and Innovation Program under grant agreement number 826013.
文摘Environmental stability is a major bottleneck of perovskite solar cells.Only a handful of studies are investigating the effect of moisture on the structural degradation of the absorber.They mostly rely on ex situ experiments and on completely degraded samples,which restrict the assessment on initial and final stage.By combining in situ X-ray diffraction under controlled 85%relative humidity,and live observations of the water-induced degradation using liquid-cell transmission electron microscopy,we reveal two competitive degradation paths leading on one hand to the decomposition of state-of-theart mixed cation/anion(Cs_(0.05)(MA_(0.17)FA_(0.83))_(0.95)Pb(Br_(0.17)I_(0.83))_(3)(CsMAFA)into PbI_(2) through a dissolution/recrystallization mechanism and,on the other hand,to a non-equilibrium phase segregation leading to CsPb_(2)Br_(5) and a Cesium-poor/iodide-rich Cs_(0.05)-x(MA_(0.17)FA_(0.83))_(0.95)Pb(Br_(0.17-2y)I_(0.83)+2y)_(3) perovskite.This degradation mechanism is corroborated at atomic-scale resolution through solid-state ^(1)H and ^(133)Cs NMR analysis.Exposure to moisture leads to a film containing important heterogeneities in terms of morphology,photoluminescence intensities,and lifetimes.Our results provide new insights and consensus that complex perovskite compositions,though very performant as champion devices,are comparatively metastable,a trait that limits the chances to achieve long-term stability.
文摘Background Transparent dressings are commonly used to cover central venous catheter sites. However, it has been suggested that they might not allow adequate moisture vapor transmission, resulting in local moistness that promotes bacterial growth. We compared the moisture vapor transmission rates （MVTRs） of different, currently used transparent and traditional gauze dressings. We aimed to determine the MVTRs at different temperatures and humidities. Methods The dressings were used to seal 50-ml plastic centrifuge tubes containing 20 ml deionized water： Tubes in group 1 were covered with 12 layers of ordinary gauze, group 2 with IV3000, group 3 with OPSITE FLEXlGRID, group 4 with 3M HP Tegaderm, and group 5 with 3M Tegaderm. The tubes were placed upright in an artificial climate cabinet, so that the dressings were not touching the water, in order to simulate the conditions of medical dressings in contact with the skin. The average MVTRs were determined under different conditions. MVTRs were also determined with tubes from groups 2-5 laid on their sides, allowing the dressings to touch the water, so simulating contact of the dressings with sweating skin, or wounded skin with exudates. We also calculated the dressings＇ self-reactive abilities by comparing their MVTRs in contact with the water surface with those when not in contact with the water surface. Results Group 1 demonstrated the highest MVTR, followed by groups 2, 4, 3 and 5 under conditions simulating contact of the dressings with normal skin at the following temperatures and humidities： 20℃/30%, 20℃/60%, 20℃/90%, 37℃/30%, 37℃/60% and 37℃/90%. When the relative humidity （RH） increased, the MVTRs decreased. The MVTRs differed significantly among different dressings and RHs： At high temperature （37℃） and high humidity （90%）, the MVTR of the transparent dressings in group 2 was higher than that of group 1 （P 〈0.01）. The reactive MVTR was highest in group 2 （10.2-16.3 times 〉MVTR） while that of group 4 was second highest （2.6-9.6 times 〉MVTR）. Conclusions RH and temperature had significant effects on the MVTRs of different dressings. The IV3000 transparent dressing used in group 2 was as effective as ordinary gauze. These results suggest that increased infection rates due to low MVTRs might not be a problem. The clinical implications of these observations for catheter-related infections need to be further investigated in multicenter studies.
