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Podzimek, Josef

doi:10.1023/a:1023305423337

Cited by 8 publications

(4 citation statements)

References 23 publications

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“…1 shows dewetting fronts in liquid polystyrene films beading off silicon substrates (the fronts move from left to right). The profiles are obtained by scanning force microscopy from the rims of circular dry patches nucleated in the films [16][17][18]. Most commonly, one observes profiles as those shown in fig.…”

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confidence: 99%

Generic Morphologies of Viscoelastic Dewetting Fronts

2002

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A simple model is put forward which accounts for the occurrence of certain generic dewetting morphologies in thin liquid coatings. It demonstrates that, by taking into account the elastic properties of the coating, a morphological phase diagram may be derived which describes the observed structures of dewetting fronts. It is demonstrated that dewetting morphologies may also serve to determine nanoscale rheological properties of liquids.

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confidence: 99%

Generic Morphologies of Viscoelastic Dewetting Fronts

2002

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“…Studies have revealed that many air pollutants are deposited via fog droplets, and the nitrogen deposition rate via fog water is of the same magnitude as that via rainwater (Igawa et al, 1998). Moreover, a simple formula for cleaning a polluted atmosphere by fog (haze) events was deduced for fog that lasts more than 4 h (Podzimek, 1998). As mentioned above (Figure 8), the atmosphere was supersaturated and condensed from fog droplets on the evening of January 16.…”

Section: Surface Meteorological Factorsmentioning

confidence: 86%

Joint Occurrence of Heavy PM2.5 Pollution Episodes and Persistent Foggy Days in Central East China

Yang

Liu

2022

Front. Environ. Sci.

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Although many severe pollution events in Central and East China have been analyzed in recent years, the heavy PM2.5 pollution episode happened on persistent foggy days from January 13 to 18, 2018 was unique, characterized by explosive increase and sharp decrease in PM2.5 (particles with kinetic equivalent diameter less than or equal to 2.5 microns) concentration. Based on hourly data of ground level meteorological parameters, PM2.5 data and CALIPSO-based (the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) aerosol data, combined with ECMWF (European Centre for Medium-Range Weather Forecasts) reanalysis data and radiosonde temperature profile, a comprehensive analysis was conducted to reveal the meteorological reasons for the evolution of the episode at horizontal and vertical scales. The PM2.5 concentration experienced four stages: a slow-increase phase, rapid-increase phase, rapid-decrease phase, and rebound phase. Results show that because Central and East China (CEC) were located at the back of a high-pressure system, humid southerly winds and near surface inversion (NSI) were responsible for the slow accumulation of pollutants. The rapid-increase phase was attributed to pollution transport at both ground level and in the lower troposphere because of weak cold air invasion. The significant subsidence at 500 hPa and 700 hPa intensified the NSI and led to dense fog. In that case, corresponding to the supersaturated atmosphere, the particles entered the fog droplets and were scavenged partly by deposition at night and were resuspended on the next day when the atmosphere was unsaturated. Our findings provide convincing evidence that surface PM2.5 rapid-decrease phase and the rebound phase were closely associated with dense fog process.

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“…This might involve new problems related to non-Newtonian behavior due to viscoelastic flow and stress relaxation. The latter has been reported to cause polymer thin film rupture [16,17] and to impact the early stage of dewetting [17]. As will be shown in the following for the mature stage, residual stress and viscoelastic properties have no impact on the shape of dewetting rims, if low shear rates are involved.…”

mentioning

confidence: 83%

“…PS(390k)) and low polydispersity (M w /M n = 1.02 − 1.09) were spin-cast from toluene solutions on freshly cleaved mica sheets and transferred to smooth hydrophobized Si wafers with a native oxide layer (obtained from Siltronic, Burghausen, Germany) by floating them on a Millipore TM water surface. To avoid residual stresses in films above the entanglement length of PS, the films were pre-annealed on the mica substrate well above their glass transition temperature (up to 3 hours at 140 • C) [16]. The prepared film thicknesses h 0 varied between 100 and 140 nm.…”

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confidence: 99%

Liquid Front Profiles Affected by Entanglement-induced Slippage

Baeumchen,

Fetzer,

Jacobs

2009

Preprint

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Hydrodynamic slippage plays a crucial role in the flow dynamics of thin polymer films, as recently shown by the analysis of the profiles of liquid fronts. For long-chained polymer films it was reported that a deviation from a symmetric profile is a result of viscoelastic effects. In this Letter, however, evidence is given that merely a slip boundary condition at the solid/liquid interface can lead to an asymmetric profile. Dewetting experiments of entangled polymer melts on diverse substrates allow a direct comparison of rim morphologies. Variation of molecular weight Mw clearly reveals that slippage increases dramatically above a certain Mw and governs the shape of the rim. The results are in accordance with the theoretical description by de Gennes.

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Cited by 8 publications

References 23 publications

Generic Morphologies of Viscoelastic Dewetting Fronts

Generic Morphologies of Viscoelastic Dewetting Fronts

Joint Occurrence of Heavy PM2.5 Pollution Episodes and Persistent Foggy Days in Central East China

Liquid Front Profiles Affected by Entanglement-induced Slippage

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