• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1563-1565
• /
• 2008

Hydrophobic plastic plates employing nano surface features are injection molded using thermoplastic materials. A variotherm molding process is devised for filling the nano pores and releasing the molded nano features from the master. The size of the molded nano surface features are about 100nm in diameter and 200nm in height. The size of the molded plate is about 30mm x 30mm and the thickness is 1mm. As molding materials, Polypropylene, PMMA, COC and PC are employed, which are all typical commodity thermoplastic materials. The mold temperature(stamper temperature) is investigated as a major processing parameter for molding high aspect ratio nano surface features. Almost fully molded nano features are fabricated above a certain level of mold temperature depends on the employing material. The contact angles on the injection molded plates are measured to estimate the hydrophobicity and found to have higher contact angle up to 180% compared to the blank plate with no surface features.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.36 no.4
• /
• pp.265-269
• /
• 2010

In this study, we varied emulsifiers and oils for obtaining nano-emulsions with low viscosity using solubilization method. We obtained the stable nano-emulsions with 100 nm droplet size composed with hexyl laurate, ceteareth-20, PEG-40 hydrogenated caster oil, glyceryl stearate, and stearic acid. This nano-emulsion was stable against time. The stability of nano-emulsions was measured through the change of particle size. The cooling process was an important factor for obtaining stable emulsions by solubilization method. Stability of nano-emulions was maximum only when cooled rapidly.

• Structural Engineering and Mechanics
• /
• v.55 no.5
• /
• pp.1001-1014
• /
• 2015

Bending analysis of functionally graded (FG) nano-plates is investigated in the present work based on a new sinusoidal shear deformation theory. The theory accounts for sinusoidal distribution of transverse shear stress, and satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. The material properties of nano-plate are assumed to vary according to power law distribution of the volume fraction of the constituents. The size effects are considered based on Eringen's nonlocal theory. Governing equations are derived using energy method and Hamilton's principle. The closed-form solutions of simply supported nano-plates are obtained and the results are compared with those of first-order shear deformation theory and higher-order shear deformation theory. The effects of different parameters such as nano-plate length and thickness, elastic foundation, orientation of foundation orthtotropy direction and nonlocal parameters are shown in dimensionless displacement of system. It can be found that with increasing nonlocal parameter, the dimensionless displacement of nano-plate increases.

• Ocean and Polar Research
• /
• v.23 no.4
• /
• pp.379-388
• /
• 2001

Ch1 a abundance, Ch1 a-specific productivity and phytoplankton growth rate in each size fraction (pico, $<2{\mu}m$; nano, $2-10{\mu}m$; micro, > $10{\mu}m$) in the waters around the South Shetland Islands (Ant-arctic Peninsula Area) were analysed. Although Ch1 a-specific productivity and growth rate were highest in micro-size fractions, ChI a abundance was highest in pico-size fractions. Selective removal of nano- and micro-size phytoplankton especially by krill and salp grazing, but not limitation of phytoplankton growth, seemed to be the major reason to explain this miss match between productivity and abundance of the phytoplankton community.

• Resources Recycling
• /
• v.18 no.6
• /
• pp.24-29
• /
• 2009

Since cerium carbonate becomes porous cerium oxide by releasing carbon dioxide and vapour steam during calcination of cerium carbonate, nano size cerium oxide can be obtained by milling calcined cerium carbonate. Therefore cerium carbonate [$Ce_2(CO_3)3{\cdot}XH_2O$] is used generally for the preparation of nano size cerium oxide. In order to obtain nano size cerium oxide from cerium carbonate prepared by reactive crystallization of cerium chloride solution and ammonium bicarnonate solution, the effects of experimental variables in the milling and calcination of cerium carbonate, such as calcination temperature, milling time, rpm of planetary mill, amount of dispersant and ball size for milling on the size of cerium oxide was investigated in this study. Cerium oxide prepared with the conditions of calcination temperature of $700^{\circ}C$, milling time of 5 hour was 160nm mean particle size.

• Korean Journal of Materials Research
• /
• v.23 no.2
• /
• pp.81-88
• /
• 2013

In this study, using a tin chloride solution as the raw material, a nano-sized tin oxide powder with an average particle size below 50 nm is generated by a spray pyrolysis process. The properties of the tin oxide powder according to the nozzle tip size are examined. Along with an increase in the nozzle tip size from 1 mm to 5 mm, the generated particles that appear in the shape of droplets maintain an average particle size of 30 nm. When the nozzle tip size increases from 1 mm to 2 mm, the average size of the generated particles is around 80-100 nm, and the ratio of the independent particles with a compact surface structure increases significantly. When the nozzle tip size is at 3 mm, the majority of the generated particles maintain the droplet shape, the average size of the droplet-shaped particles increases remarkably compared to the cases of other nozzle tip sizes, and the particle size distribution also becomes extremely irregular. When the nozzle tip size is at 5 mm, the ratio of droplet-shaped particles decreases significantly and most of the generated particles are independent ones with incompact surface structures. Along with an increase in the nozzle tip size from 1 mm to 3 mm, the XRD peak intensity increases, whereas the specific surface area decreases greatly. When the nozzle tip size increases up to 5 mm, the XRD peak intensity decreases significantly, while the specific surface area increases remarkably.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.386-386
• /
• 2012

For white light emitting diode (LED) applications, it has been reported that Y3Al5O12:Ce3+ (YAG:Ce) in nano-sized phosphor performs better than it does in micro-sized particles. This is because nano-sized YAG:Ce can reduce internal light scattering when coated onto a blue LED surface. Recently, there have been many reports on the synthesis of nano-sized YAG particles using bottom-up method, such as co-precipitation method, sol-gel process, hydrothermal method, solvothermal method, and glycothermal method. However, there has been no report using top-down method. Top-down method has advantages than bottom-up method, such as large scale production and easy control of doping concentration and particle size. Therefore, in this study, nano-sized YAG:Ce phosphors were synthesized by a high energy beads milling process with varying beads size, milling time and milling steps. The beads milling process was performed by Laboratory Mill MINICER with ZrO2 beads. The phase identity and morphology of nano-sized YAG:Ce were characterized by X-ray powder diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively. By controlling beads size, milling time and milling steps, we synthesized a size-tunable and uniform nano-sized YAG:Ce phosphors which average diameters were 100, 85 and 40 nm, respectively. After milling, there was no impurity and all of the peaks were in good agreement with YAG (JCPDS No. 33-0040). Luminescence and quantum efficiency (QE) of nano-sized YAG:Ce phosphors were measured by fluorescence spectrometer and QE measuring instrument, respectively. The synthesized YAG:Ce absorbed light efficiently in the visible region of 400-500 nm, and showed single broadband emission peaked at 550 nm with 50% of QE. As a result, by considering above results, high energy beads milling process could be a facile and reproducible synthesis method for nano-sized YAG:Ce phosphors.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05a
• /
• pp.183-186
• /
• 2004

Nano particles-containing CMS membranes were prepared by pyrolysis of polyimides dispersed uniformly with precursors and their gas separation performances were examined, to elucidate the permeation mechanism and to further improve the gas separation performance. Consequently, it was suggested that the separation performance could be controlled by doping nano-particles in the CMS membranes, and that optimization of various factors, such as the size, content, and dispersion state of the nano particles would contribute for further improvement of the gas separation performance.

• Applied Chemistry for Engineering
• /
• v.21 no.6
• /
• pp.670-675
• /
• 2010

Inorganic-organic hybrid material such as vinyl-nano sized silica ball was synthesized by acrylo-alkoxysilane and nano silica ball with different particle size. And then they were formulated into acrylic-melamine clearcoat. This material is fully characterized with various analytical methods and applied for strength measurement. The glossy effect, matting effect and anti-scratching properties of materials were investigated for further growth and maintenance. When the particle size of nano silica ball is 20~30 nm, the glossy retain effect was increased by 7% compared to bare acrylic-melamine clearcoat. When a commercially available silica Aerosil 200 (Hydrophilic fumed silica, average particle size 12 nm, Degussa) react with vinyl alkoxysilane vinyl-fumed silica complex form. The vinyl-fumed silica along with clearcoat increases only 2% increase at glossy retain. Nano-scratch test results also support the glossy retain effect of vinyl nano-sized silica ball in clearcoat.

• Advances in nano research
• /
• v.9 no.1
• /
• pp.1-13
• /
• 2020

In this work, the electrical potential (EP) technique with an artificial neural networks (ANNs) for monitoring of nanostructures are used for the first time. This study employs an expert system to identify size and localize hidden nano-delamination (N.Del) inside layers of nano-pipe (N.P) manufactured from Basalt Fiber Reinforced Polymer (BFRP) laminate composite by using low-cost monitoring method of electrical potential (EP) technique with an artificial neural networks (ANNs), which are combined to decrease detection effort to discern N.Del location/size inside the N.P layers, with high accuracy, simple and low-cost. The dielectric properties of the N.P material are measured before and after N.Del introduced using arrays of electrical contacts and the variation in capacitance values, capacitance change and node potential distribution are analyzed. Using these changes in electrical potential due to N.Del, a finite element (FE) simulation model for N.Del location/size detection is generated by ANSYS and MATLAB, which are combined to simulate sensor characteristic, therefore, FE analyses are employed to make sets of data for the learning of the ANNs. The method is applied for the N.Del monitoring, to minimize the number of FE analysis in order to keep the cost and save the time of the assessment to a minimum. The FE results are in excellent agreement with an ANN and the experimental results available in the literature, thus validating the accuracy and reliability of the proposed technique.