scholarly journals Formation of highly resistive SiO2 nanoparticle layers from the aerosol by electrostatic precipitation at 200 °C: observations on back corona and nanoparticle layer structure

2021 ◽  
Vol 23 (8) ◽  
Author(s):  
Patrick Bürger ◽  
Ulrich Riebel
Keyword(s):  
Electrostatic Precipitator ◽  
Layer Structure ◽  
Fold Increase ◽  
Opposite Polarity ◽  
Electrostatic Precipitation ◽  
Free Electrons ◽  
Electron Multiplication ◽  
Nanoparticle Layer ◽  
Small Pore ◽  
Thermionic Field Emission

AbstractIn this study, a flame-generated nm-range SiO2 aerosol (approx. 170 nm median aggregate diameter) is fed into an electrostatic precipitator with an operating temperature of 200 °C. While a highly porous layer of SiO2 nanoparticles (NPs) is deposited by electrostatic precipitation, a decrease of current uptake is observed initially, indicating exceptionally high values of the electric field within the layer (> 100 kV/mm) and of the layer resistivity (> 1013 Ω∙cm). Later a strong (13- to 17-fold) increase of current uptake is observed. Aerosol charge measurements show that charges of opposite polarity are emitted from the NP layer. Investigation of the NP layer by SEM shows that charge-emitting structures with a polarity-dependent morphology develop on an originally homogeneous NP layer. Based on the experimental evidence, the mechanisms of charge emission and structure formation are discussed. Charge emission from the precipitated dust layer is known as back corona in the field of electrostatic precipitation. It appears that the mechanisms of back corona observed with SiO2 NP layers are quite distinct from those observed with µm-range particles. While gas discharges inside the NP layer are suppressed due to small pore size, back corona inside the NP layers is apparently initiated by thermionic field emission of free electrons and secondary electron multiplication within the NP layer.

Analysis of Coating Pore Structure and its Effect on Printability of Low Gloss Coated Paper

2011 ◽  
Vol 236-238 ◽  
pp. 1178-1182
Author(s):  
Yan Xin Liu ◽  
Yu Long Wang ◽  
Shen Tao Qin ◽  
Fei Fei Liu
Keyword(s):  
Pore Structure ◽  
Pore Size ◽  
Pore Volume ◽  
Coating Layer ◽  
Layer Structure ◽  
Capillary Absorption ◽  
Coated Paper ◽  
Base Paper ◽  
Small Pore ◽  
Coating Color

Coating pore structure of low gloss coated paper based on different pigment blends was analyzed using mercury intrusion method in this paper. The results show that pore size of coating layer structure of low gloss coated paper ranges from 20nm-500nm, and the range from 500nm-5000nm is mainly from base paper and interactions between coating color and base paper. Printability of coated paper can be well related with coating pore structure. Print gloss is strongly influenced by pore size and pore volume. Large pore diameters and small pore volume of coating layer structure can improve print gloss. Ink density increases with the increasing of pore diameter while the pore volume is kept constant. The increasing of pore volume of coat layer structure will improve capillary absorption and then improve ink absorption. The control of coating pore structure is very important for producing low gloss coated paper.

Study on Water Spraying System in Wet Electrostatic Precipitator

2013 ◽  
Vol 423-426 ◽  
pp. 1732-1736 ◽  
Author(s):  
Li Chun Xiao ◽  
Zhi Jiang Ding ◽  
Qiang Li
Keyword(s):  
High Efficiency ◽  
Electrostatic Precipitator ◽  
Collection Efficiency ◽  
Water Pressure ◽  
Operating Voltage ◽  
Electrostatic Precipitation ◽  
Dust Collection ◽  
Dust Collection Efficiency

The dust collected in the polar plates can be washed out by a spraying system in the wet electrostatic precipitator. It is important to keep the spraying system having a high efficiency lest the dust returns to the gas again. The performance of the spraying system in the electrostatic precipitation and its influence on the dust collection efficiency are presented in the paper. The atomization characteristic of the spraying nozzle is measured by changing the water pressure and operating voltage. The results show that: Collection efficiency of the electrostatic precipitation is over 99.5 % when the water pressure is 0.4 MPa.When the spraying mists diameter is 100 μm, the collection efficiency is 92 % for the dust diameter under 10 μm. It will provide a basis for the design of spraying system in wet electrostatic precipitation by this analysis.

scholarly journals Эллипсометрическое исследование тонкопленочных структур аморфного гидрогенизированного углерода и наночастиц золота

2019 ◽  
Vol 127 (11) ◽  
pp. 846 ◽  
Author(s):  
В.А. Толмачев ◽  
Д.П. Щербинин ◽  
Е.А. Коншина
Keyword(s):  
Gold Film ◽  
Layer Structure ◽  
Hybrid Structure ◽  
Spectral Features ◽  
Spectral Ellipsometry ◽  
Lorentz Oscillator ◽  
Nanoparticle Layer ◽  
Before And After ◽  
Spectrophotometric Data ◽  
Amorphous Hydrogenated Carbon

In this work, the optical constant films of amorphous hydrogenated carbon (a-C: H) and a hybrid structure based on it with a granulated gold film before and after their annealing at 300 °C were studied by spectral ellipsometry. The dispersions n (λ) and k (λ) of the a-C:H film were established using the Cauchy approximation and its thickness. The spectral features of the Au plasmon nanoparticle layer deposited on the a-C:H surface were modeled as an effective medium and a Lorentz oscillator. The parameters of the films and their thickness were determined by fitting the calculated spectra to the ellipsometric spectra  (λ) and  (λ). The obtained data were used to determine the parameters of the Lorentz oscillator in the model of a-C:H / Au two-layer structure. As a result of the a-C:H / Au structure annealing, the intensity of the maxima in the spectra n and k increased, their position shifted to the blue region, and the half-width of the bands decreased. The observed changes in the ellipsometric spectra are completely consistent with the spectrophotometric data of this structure.

Nanoparticles at the Polydimethylsiloxane Droplet/Water Interface

2005 ◽  
Vol 58 (9) ◽  
pp. 664 ◽  
Author(s):  
Spomenka Simovic ◽  
Clive A. Prestidge
Keyword(s):  
Electrical Properties ◽  
Layer Structure ◽  
Water Interface ◽  
Adsorption Behaviour ◽  
Nanoparticle Layer ◽  
Hydrophobically Modified ◽  
Salt Addition ◽  
Wide Range ◽  
Droplet Stability ◽  
Water Transport Properties

The adsorption behaviour of nanoparticles at the polydimethylsiloxane droplet/water interface and the influence of particle hydrophobicity, droplet deformability, and the surface electrical properties of both particles and droplets (as controlled by pH and salt concentration) are reported. Adsorption of hydrophilic nanoparticles is weakly influenced by pH but significantly influenced by salt addition, whereas for hydrophobically modified nanoparticles a balance of hydrophobic and electrostatic forces controls adsorption over a wide range of pH and salt concentrations. The relationships between the adsorbed nanoparticle layer structure, droplet stability, and the oil-to-water transport properties have also been elucidated.

Efficient Near Infrared Si/Ge Quantum Dot Photo-Detector Based on a Heterojunction Bipolar Transistor

2003 ◽  
Vol 770 ◽  
Author(s):  
Anders Elfving ◽  
Mats Larsson ◽  
Per-Olof Holtz ◽  
Göran V. Hansson ◽  
Wei-Xin Ni
Keyword(s):  
Near Infrared ◽  
Layer Structure ◽  
Electrical Contact ◽  
Fold Increase ◽  
Normal Incidence ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Time Resolved ◽  
Light Coupling ◽  
Ge Quantum Dot

AbstractGe dots embedded in Si offer the possibility of Si-based light detection at 1.3-1.55 μm. In this communication, we report a very efficient photo-detector based on a Si/SiGe heterojunction bipolar transistor structure with 10 Ge dot layers (8 ML Ge each) incorporated in the basecollector junction. The device structures were grown using low-temperature molecular beam epitaxy, and fabricated for both normal and edge incidence with no electrical contact to the base. The processed Ge-dot transistor detectors revealed a rather low dark current density, 0.01 mA/cm2 at -2 V. Photoconductivity measurements were performed at room temperature. At 1.31 μm, responsivity values of 50 mA/W at normal incidence have been directly measured at Vce = -4 V, without involving any rescaling factor due to light coupling. This value is a ∼250-fold increase compared to a reference p-i-n diode with the same dot layer structure, due to the current amplification function of the transistor. For a rib waveguide device, a very high responsivity value of about 470 mA/W (Vce = -4V) has been obtained at 1.31 μm. Measurements were also performed at 1.55 μm, and the photo-response of the waveguide phototransistor was 25 mA/W, which is again a large improvement compared with the reference waveguide photodiode (∼1 mA/W). Moreover, time-resolved photoconductivity measurements have been carried out. The results have indicated that the device frequency performance is primarily limited by the emitterbase junction capacitance.

scholarly journals Effect of phloretin on the permeability of thin lipid membranes.

1976 ◽  
Vol 67 (6) ◽  
pp. 749-771 ◽  
Author(s):  
O S Andersen ◽  
A Finkelstein ◽  
I Katz ◽  
A Cass
Keyword(s):  
Dipole Moment ◽  
Partition Coefficient ◽  
Lipid Membranes ◽  
Membrane Surface ◽  
Fold Increase ◽  
Opposite Polarity ◽  
Dipole Potential ◽  
Asymmetrical Effect ◽  
Carbonyl Cyanide ◽  
Nonelectrolyte Permeability

Phloretin dramatically increases cation conductances and decreases anion conductances of membranes treated with ion carriers (nonactin, valinomycin, carbonyl-cyanide-m-chlorophenylhydrazone [CCCP], and Hg(C6F5)2) or lipophilic ions (tetraphenylarsonium [tphAs+] and tetraphenylborate [TPhB-]). For example, on phosphatidylethanolamine membranes, 10(-4) M phloretin increases K+ -nonactin and TPhAs+ conductances and decreases CCCP- and TPhB- conductances 10(3)-fold; on lecithin: cholesterol membranes, it increases K+-nonactin conductance 10(5)-fold and decreases CCCP- conductance 10(3)-fold. Similar effects are obtained with p- and m-nitrophenol at 10(-2) M. These effects are produced by the un-ionized form of phloretin and the nitrophenols. We believe that phloretin, which possesses a large dipole moment, adsorbs and orients at the membrane surface to introduce a dipole potential of opposite polarity to the preexisting positive one, thus increasing the partition coefficient of cations into the membrane interior and decreasing the partition coefficient of anions. (Phloretin may also increase the fluidity of cholesterol-containing membranes; this is manifested by its two- to three-fold increase in nonelectrolyte permeability and its asymmetrical effect on cation and anion conductances in cholesterol-containing membranes.) It is possible that pholoretin's inhibition of chloride, urea, and glucose transport in biological membranes results from the effects of these intense intrafacial dipole fields on the translocator(s) of these molecules.

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