• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.8
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• pp.617-623
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• 2008

The membrane filter adhered with nanostructured porous layer was made by heat treatment after deposition of nanoparticle-agglomerates sintered in aerosol phase onto a conventional micron-fibrous metal filter as a substrate filter. The Sintered-Nanoparticle-Agglomerates-coated NanoStructured porous layer Membrane Filter (SNA-NSMF), whose the filtration performance was improved compared with the conventional metal membrane filters, was developed by adhesion of nanoparticle-agglomerates of dendrite structure sintered onto the micron-fibrous metal filter. The size of nanoparticle-agglomerates of dendrite structure decreased with increasing the sintering temperature because nanoparticle-agglomerates shrank. When shrinking nanoparticle-agglomerates were deposited and treated with heat onto the conventional micron-fibrous metal filter, pore size of nanostructured porous layer decreased. Therefore, pressure drops of SNA-NSMFs increased from 0.3 to 0.516 kPa and filtration efficiencies remarkably increased from 95.612 to 99.9993%.

• Nuclear Engineering and Technology
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• v.43 no.3
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• pp.205-216
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• 2011

Recently, many research studies have investigated the enormous critical heat flux (CHF) enhancement caused by nanofluids during pool boiling and flow boiling. One of the main reasons for this enhancement is nanoparticle deposition on the heated surface. However, in real applications, nanofluids create many problems when used as working fluids because of sedimentation and aggregation. Therefore, artificial surfaces on silicon and metal have been developed to create an effect similar to that of nanoparticle deposition. These modified surfaces have proved capable of greatly increasing the CHF during pool boiling, and good results have also been observed during flow boiling. In this study, we demonstrate that the wetting ability of a surface, i.e., wettability, and the liquid spreading ability (hydrophilic surface property), are key parameters for increasing the CHF during both pool and flow boiling. We also demonstrate that when the fuel surface in nuclear power plants is modified in a similar manner, it has the same effect, producing a large CHF enhancement.

• 한국전기화학회:학술대회논문집
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• 2003.04a
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• pp.33-33
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• 2003

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.397-401
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• 2008

The nanoparticle-agglomerates are synthesized by laser ablation, which have the morphology of dendrite structure. The filtration performance of a conventional micron-fibrous metal filter was improved by adhering nanoparticle-agglomerates onto the filter surface. The Sintered-Nanoparticle-Agglomerates-adhered Filter (SNAF) adhered with nanostructured material was made by heat treatment after deposition of nanoparticle-agglomerates sintered in aerosol phase onto the micron-fibrous metal filter. As the sintering temperature increases, the pressure drop of the filter increases a little but the filtration efficiency increases remarkably. This is due to increase of surface area of nanoparticle-agglomerates adhered onto the micron-fibrous metal filter.

• Current Photovoltaic Research
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• v.1 no.1
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• pp.59-62
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• 2013

We investigated the effects of ZnO thin film deposition methods on the performance of inverted polymer solar cells with a structure of ITO/ZnO/P3HT:PCBM/MoO3/Al. The ZnO thin films were deposited by various methods (spin coating of nanoparticles, sol-gel process, atomic layer deposition) and their morphology was analyzed by atomic force microscopy (AFM). The device with ZnO nanoparticle thin films showed the highest power conversion efficiency of 3 % with low series resistance and high shunt resistance. The superior performance of the device with the ZnO nanoparticle layer is attributed to better electron extraction capability.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2056-2060
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• 2007

A successful combination of “oxygen-assisted chemical vapor deposition (CVD) process” and Co catalyst nanoparticles to grow highly pure single walled carbon nanotubes (SWNTs) was demonstrated. Recently, it was reported that addition of small amounts of oxygen during CVD process dramatically increased the purity and yield of carbon nanotubes. However, this strategy could not be applied for discrete Fe nanoparticle catalysts from which appropriate yields of SWNTs could be grown directly on solid substrates, and fabricated into field effect transistors (FETs) quite efficiently. The main reason for this failure is due to the carbothermal reduction which results in SiO2 nanotrench formation. We found that the oxygen-assisted CVD process could be successfully applied for the growth of highly pure SWNTs by switching the catalyst from Fe to Co nanoparticles. The topological morphologies and p-type transistor electrical transport properties of the grown SWNTs were examined by using atomic force microscope (AFM), Raman, and from FET devices fabricated by photolithography.

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.111-117
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• 2019

This study proposed the fabrication and deposition of high purity crystalline $core-TiO_2/shell-Al_2O_3$ nanoparticles. Morphological properties of $core-TiO_2$ and coated $shell-Al_2O_3$ were confirmed by transmission electron microscope (TEM) and transmission electron microscope - energy dispersive spectroscopy (TEM-EDS). The electrical properties of the prepared $core-TiO_2/shell-Al_2O_3$ nanoparticles were evaluated by applying them to a working electrode of a Dye-Sensitized Solar Cell (DSSC). The particle size, growth rate and the main crystal structure of $core-TiO_2$ were analyzed through dynamic light scattering system (DLS), scanning electron microscope (SEM) and X-ray diffraction (XRD). The $core-TiO_2$, which has a particle size of 17.1 nm, a thin film thickness of $20.1{\mu}m$ and a main crystal structure of anatase, shows higher electrical efficiency than the conventional paste-based dye-sensitized solar cell (DSSC). In addition, the energy conversion efficiency (6.28%) of the dye-sensitized solar cell (DSSC) using the $core-TiO_2/shell-Al_2O_3$ nanoparticles selectively controlled to the working electrode is 26.1% higher than the energy conversion efficiency (4.99%) of the dye-sensitized solar cell (DSSC) using the conventional paste method.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3168-3172
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• 2007

As the minimum feature size decreases, control of contamination by nanoparticles is getting more attention in semiconductor process. Cleaning technology which removes nanoparticles is essential to increase yield. A reference wafer on which particles with known size and number are deposited is needed to evaluate the cleaning process. We simulated particle trajectories in the chamber by using FLUENT and designed a particle deposition system which consists of scanning mobility particle sizer (SMPS) and deposition chamber. Charged monodisperse particles are generated using SMPS and deposited on the wafer by electrostatic force. The experimental results agreed with the simulation results well in terms of particle number and deposition area according to particle size, flow rate and deposition voltage.

• Journal of the Semiconductor & Display Technology
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• v.4 no.1 s.10
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• pp.49-53
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• 2005

The nanoparticle deposition chamber, which is used for quantum dot semiconductor memory applications, is designed by means of numerical simulation. In this research, the numerical simulations for deposition chamber were performed by commercial software, FLUENT. The deposition of nanoparticles is calculated by diffusion force, thermophoresis and electrophoresis of particles. As a results, when the diffusion force was considered, the most of particles deposited in the wall of deposition chamber. But as considering thermophoresis and electrophoresis of particles, the particles were deposited wafer surface, perfectly.

• Particle and aerosol research
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• v.5 no.3
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• pp.95-109
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• 2009

A low temperature plasma process has been widely used for semiconductor fabrication and can also be applied for the preparation of solar cell, MEMS or NEMS, but they are notorious in the point of particle contamination. The nano-sized particles can be generated in the low temperature plasma process and they can induce several serious defects on the performance and quality of microelectronic devices and also on the cost of final products. For the preparation of high quality thin films of high efficiency by the low temperature plasma process, it is desirable to increase the deposition rate of thin films with reducing the particle contamination in the plasmas. In this paper, we introduced the studies on the generation and growth of nanoparticles in the low temperature plasmas and tried to introduce the recent interesting studies on nanoparticle generation in the plasma reactors.