The morphology of sediment particles plays an important role in interfacial interactions.The difficulties in complex morphological description significantly limit the research on interfacial interactions.In this study...The morphology of sediment particles plays an important role in interfacial interactions.The difficulties in complex morphological description significantly limit the research on interfacial interactions.In this study,images of a single sediment particle extracted from electron microscope photos were used to analyze the gray values and present the probability of shape of the sediment particles.Moreover,the morphological features of the sediment particles were qualitatively described using the fractal method(surface area-volume method).The fractal dimension D of a single sediment particle was calculated to analyze the features and quantitative complexity of the sediment particle morphology.Results indicate that the probability of shape can provide intuitive morphological structure and fully describe the complex morphological characteristics of sediment particle surfaces.The fractal dimension abstractly described the complexity of the morphology of a sediment particle surface and matched well with the experimental results.The methods discussed in this study are suitable for describing the complex morphology of the sediment particle surface and lay the scientific foundation for further research on the interfacial interaction between the sediment particle and the pollutant.展开更多
The effect of dust particles on electric contacts and a hazardous size range of hard dust particles using a rigid model were discussed before. As further research, elastic-plastic model of finite element analysis was ...The effect of dust particles on electric contacts and a hazardous size range of hard dust particles using a rigid model were discussed before. As further research, elastic-plastic model of finite element analysis was established in this work, which is closer to real condition. In this work, the behavior of large size and small size particles, and the influence of particles hardness were investigated. The calculating result of small-size particles presents a general hazardous size coefficient for different contact surface morphology; for large-size particles, it presents a hazardous size coefficient for complicated composition of the dust. And the effect of the dust shape is also discussed.展开更多
The effects of ionic emulsifier, sodium dodecylbenzene sulfate (SDBS), on the formation of the multihollow structures in sub-micron sized polymer particles produced by alkali/acid posttreatment were investigated. The ...The effects of ionic emulsifier, sodium dodecylbenzene sulfate (SDBS), on the formation of the multihollow structures in sub-micron sized polymer particles produced by alkali/acid posttreatment were investigated. The original latex particles with narrow size distribution were synthesized by a new sequence emulsifier-free/emulsifier emulsion copolymerization of styrene (St) and methacrylic acid (MAA). Results indicated that the pore size decreased and the pore number increased with the increase of SDBS amount, and the morphology of the posttreated latex particles was also significantly influenced by the introducing time of SDBS in the preparation of the original latex particles, and a suitable introducing time was 3 h of polymerization. (c) 2007 Cheng You Kan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
Wide-angle light scattering(WALS)was used for in situ measurements of droplet and nanoparticle size distributions during the synthesis of titania and iron oxide particles from liquid precursor solutions in the standar...Wide-angle light scattering(WALS)was used for in situ measurements of droplet and nanoparticle size distributions during the synthesis of titania and iron oxide particles from liquid precursor solutions in the standardized SpraySyn burner for spray flame synthesis.Titania was synthesized from titanium tetraisopropoxide(TTIP)and iron oxide from iron(II)nitrate nonahydrate(INN)using ethanol(EtOH)as solvent.Scattering images were taken at heights up to 120 mm above the burner surface and classified into droplet and particle scattering.Droplet size distributions were derived from a sequential analysis of scattering data containing the oscillating Mie pattern,the lognormal size distribution parameters for spherical and fractal particle fractions from a multivariate approach on averaged particle scattering data.The results show that the precursor addition leads to altered evaporation behavior and even droplet disruption probably induced by puffing or micro-explosions compared to pure EtOH.In the case of TTIP(a hygroscopic alkoxide),the synthesis of a large fraction of spheres was observed,while the nitrate INN leads to the formation of mostly fractal aggregates.展开更多
Aluminum(Al) particles are commonly added to energetic materials including propellants,explosives and pyrotechnics to increase the overall energy density of the composite,but aluminum agglomeration on the combustion s...Aluminum(Al) particles are commonly added to energetic materials including propellants,explosives and pyrotechnics to increase the overall energy density of the composite,but aluminum agglomeration on the combustion surface may lower the combustion efficiency of propellants,resulting in a loss in twophase flow.Therefore,it is necessary to understand the agglomeration mechanism of aluminum particles on the combustion surface.In this paper,a high-pressure sealed combustion chamber is constructed,and high-speed camera is used to capture the whole process of aluminum accumulation,aggregation and agglomeration on the combustion surface,and the secondary agglomeration process near the combustion surface.The microscopic morphology and chemical composition of the condensed combustion products(CCPs) are then studied by using scanning electron microscopy coupled with energy dispersive(SEM-EDS) method.Results show that there are three main types of condensed combustion products:small smoke oxide particles oxidized by aluminum vapor,usually less than 1 μm;typical agglomerates formed by the combustion of aluminum agglomerates;carbonized agglomerates that are widely distributed,usually formed by irregular movements of aluminum agglomerates.The particle size of condensed combustion products is measured by laser particle size meter.As the pressure increases from 0.5 MPa to 1.0 MPa in nitrogen,the mass average particle size of aluminum agglomerates decreases by 49.7%.As the ambient gas is changed from 0.5 MPa nitrogen to 0.5 MPa air,the mass average particle size of aluminum agglomerates decreases by 67.3%.Results show that as the ambient pressure increases,the higher oxygen content can improve combustion efficiency and reduce the average agglomeration size of aluminum particles.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50909107)the China Post-doctoral Science Special Foundation (Grant No. 201003385)Young Teachers Cultivation Project from Sun Yat-sen University (Grant No. 37000-3161402)
文摘The morphology of sediment particles plays an important role in interfacial interactions.The difficulties in complex morphological description significantly limit the research on interfacial interactions.In this study,images of a single sediment particle extracted from electron microscope photos were used to analyze the gray values and present the probability of shape of the sediment particles.Moreover,the morphological features of the sediment particles were qualitatively described using the fractal method(surface area-volume method).The fractal dimension D of a single sediment particle was calculated to analyze the features and quantitative complexity of the sediment particle morphology.Results indicate that the probability of shape can provide intuitive morphological structure and fully describe the complex morphological characteristics of sediment particle surfaces.The fractal dimension abstractly described the complexity of the morphology of a sediment particle surface and matched well with the experimental results.The methods discussed in this study are suitable for describing the complex morphology of the sediment particle surface and lay the scientific foundation for further research on the interfacial interaction between the sediment particle and the pollutant.
文摘The effect of dust particles on electric contacts and a hazardous size range of hard dust particles using a rigid model were discussed before. As further research, elastic-plastic model of finite element analysis was established in this work, which is closer to real condition. In this work, the behavior of large size and small size particles, and the influence of particles hardness were investigated. The calculating result of small-size particles presents a general hazardous size coefficient for different contact surface morphology; for large-size particles, it presents a hazardous size coefficient for complicated composition of the dust. And the effect of the dust shape is also discussed.
文摘The effects of ionic emulsifier, sodium dodecylbenzene sulfate (SDBS), on the formation of the multihollow structures in sub-micron sized polymer particles produced by alkali/acid posttreatment were investigated. The original latex particles with narrow size distribution were synthesized by a new sequence emulsifier-free/emulsifier emulsion copolymerization of styrene (St) and methacrylic acid (MAA). Results indicated that the pore size decreased and the pore number increased with the increase of SDBS amount, and the morphology of the posttreated latex particles was also significantly influenced by the introducing time of SDBS in the preparation of the original latex particles, and a suitable introducing time was 3 h of polymerization. (c) 2007 Cheng You Kan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金funded by the German Research Foundation DFG under grants WI1602/16-1 and WI1602/16-2.
文摘Wide-angle light scattering(WALS)was used for in situ measurements of droplet and nanoparticle size distributions during the synthesis of titania and iron oxide particles from liquid precursor solutions in the standardized SpraySyn burner for spray flame synthesis.Titania was synthesized from titanium tetraisopropoxide(TTIP)and iron oxide from iron(II)nitrate nonahydrate(INN)using ethanol(EtOH)as solvent.Scattering images were taken at heights up to 120 mm above the burner surface and classified into droplet and particle scattering.Droplet size distributions were derived from a sequential analysis of scattering data containing the oscillating Mie pattern,the lognormal size distribution parameters for spherical and fractal particle fractions from a multivariate approach on averaged particle scattering data.The results show that the precursor addition leads to altered evaporation behavior and even droplet disruption probably induced by puffing or micro-explosions compared to pure EtOH.In the case of TTIP(a hygroscopic alkoxide),the synthesis of a large fraction of spheres was observed,while the nitrate INN leads to the formation of mostly fractal aggregates.
基金supported by the National Natural Science Foundation of China (Grant No.52006099)the Fundamental Research Funds of the Central Universities (Grant No.30920021102,No.309181B8812)the Six Talent Peaks Project of Jiangsu Province of China (Grant No.2016-HKHT-017)。
文摘Aluminum(Al) particles are commonly added to energetic materials including propellants,explosives and pyrotechnics to increase the overall energy density of the composite,but aluminum agglomeration on the combustion surface may lower the combustion efficiency of propellants,resulting in a loss in twophase flow.Therefore,it is necessary to understand the agglomeration mechanism of aluminum particles on the combustion surface.In this paper,a high-pressure sealed combustion chamber is constructed,and high-speed camera is used to capture the whole process of aluminum accumulation,aggregation and agglomeration on the combustion surface,and the secondary agglomeration process near the combustion surface.The microscopic morphology and chemical composition of the condensed combustion products(CCPs) are then studied by using scanning electron microscopy coupled with energy dispersive(SEM-EDS) method.Results show that there are three main types of condensed combustion products:small smoke oxide particles oxidized by aluminum vapor,usually less than 1 μm;typical agglomerates formed by the combustion of aluminum agglomerates;carbonized agglomerates that are widely distributed,usually formed by irregular movements of aluminum agglomerates.The particle size of condensed combustion products is measured by laser particle size meter.As the pressure increases from 0.5 MPa to 1.0 MPa in nitrogen,the mass average particle size of aluminum agglomerates decreases by 49.7%.As the ambient gas is changed from 0.5 MPa nitrogen to 0.5 MPa air,the mass average particle size of aluminum agglomerates decreases by 67.3%.Results show that as the ambient pressure increases,the higher oxygen content can improve combustion efficiency and reduce the average agglomeration size of aluminum particles.
