• Mass Spectrometry Letters
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• v.14 no.4
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• pp.147-152
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• 2023

The increasing demand for two-dimensional imaging analysis using optical or electronic microscopic techniques has led to an increase in the use of simple one-dimensional and two-dimensional mass spectrometry imaging. Among these imaging methods, secondary-ion mass spectrometry (SIMS) has the best spatial resolution using a primary ion beam with a relatively insignificant beam diameter. Until recently, SIMS, which uses high-energy primary ion beams, has not been used to analyze molecules. However, owing to the development of cluster ion beams, it has been actively used to analyze various organic molecules from the surface. Researchers and commercial SIMS companies are developing cluster ion beams to analyze biological samples, including amino acids, peptides, and proteins. In this study, a water droplet ion beam for surface analysis was realized. Water droplets ions were generated via electrospraying in a vacuum without desolvation. The generated ions were accelerated at an energy of 10 keV and collided with the target sample, and secondary ion mass spectra were obtained for the generated ions using ToF-SIMS. Thus, the proposed water droplet ion-beam device showed potential applicability as a primary ion beam in SIMS.

• Journal of Powder Materials
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• v.24 no.1
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• pp.46-52
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• 2017

Fecralloy coating layer with large surface area is suitable for use as a filter media for efficient removal of hot gaseous pollutants exhausted from combustion processes. For uniform preparation of a Fecralloy coating layer with large surface area and strong adhesion to substrate, electrospray coating and thermal treatment processes are experimentally optimized in this study. A nano-colloidal solution with 0.05 wt% Fecralloy nanoparticles is successfully prepared. Optimized electrospraying conditions are experimentally discovered to prepare a uniform coating layer of Fecralloy nano-colloidal solution on a substrate. Drying the electrospray coated Fecralloy nano-colloidal solution layer at $120^{\circ}C$ and subsequent heating at $600^{\circ}C$ are the best post-treatment for enhancing the adhesion force and surface roughness of the Fecralloy coating layer on a substrate. An electrospray coating system, consisting of several multi-groove nozzles, is also experimentally confirmed as a reasonable device for uniform coating of Fecralloy nano-colloid on a large area substrate.

• Polymer(Korea)
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• v.33 no.4
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• pp.353-357
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• 2009

Spray drying is an effective and stable process, which has been widely used to produce pharmaceutical powders. In the traditional spray drying process, it was not quite easy to control the aggregation and the size of particles. Particularly, the preparation of polymeric particles was relatively hard compared to the preparation of food and pharmaceutical ingredients, typically organic materials of small molecular weights. In this study, modification of a conventional spray dryer was tried to use electrical charge and co-axial nozzles to prepare polymeric particles. Poly(ethylene glycol) and poly (D,L-lactide-co-glycolide) were used as the inner polymeric materials, and lactose as the outer shell materials. The results showed that electrohydrodynamic spray-dried particles had a relatively uniform size and particle morphology, and the aggregation of particles could be suppressed compared to the conventional spray-dried particles. The electrohydrodynamic spray-dried powders consisted of spherical particles of $2{\sim}5{\mu}m$ diameters.

• Particle and aerosol research
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• v.13 no.4
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• pp.151-158
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• 2017

Electrostatic precipitator is widely used to remove particulate matters in indoor air and industrial flue gas due to low pressure drop and high collection efficiency. However, it has a low collection efficiency for the submicrometer sized particles. Electrospraying is a potential method to increase the particle charging efficiency, which results in increased collection efficiency. Although particle charging efficiency is highly dependent upon droplet size, the effective measuring method of the droplets is still uncertain. Tap water was electrosprayed in this study, and the images of electrosprayed droplets were taken with a high speed camera coupled with several visualization methods in order to measure the droplets size. The droplet size distribution was determined by an image processing with an image-J program. As a result, a droplet measured by a laser visualization, had a half size of that by a Xenon light visualization. In addition, the experimentally measured droplet sizes were a good agreement with the predicted values suggested by $Fern{\acute{a}}ndez$ de la Mora and Loscertales(1994).