• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.101-102
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• 2012

• Membrane and Water Treatment
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• v.8 no.6
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• pp.613-623
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• 2017

We report the novel thin film composite RO membrane modified by graphene oxide. The thin film composite RO membrane was exposed to 2000 mg/l sodium hypochloride; thereafter it was subjected to different graphene oxide concentration ranging from 50 mg/l to 1000 mg/l in water. The resultant membrane was crosslinked with 5000 mg/l N-hydroxysuccinimide. The performance of different membranes were analysed by solute rejection and water-flux measurement. It was found that 100 mg/l graphene oxide exposure followed by 5000 mg/l N-hydroxysuccinimide treatment resulted in the membrane with the highest solute rejection of 97.78% and water-flux of 4.64 Liter per sqm per hour per bar g. The membranes were characterized by contact angle for hydrophilicity, scanning electron micrographs for surface morphology, energy dispersive X-Ray for chemical composition of the surface, Atomic force microscope for surface roughness, ATR-FTIR for chemical structure identification. It was found that the graphene oxide modified membrane increases the salt rejection performance after exposure to high-fouling water containing albumin. Highly hydrophilic, antifouling surface formation with the nanomaterial led to the improved membrane performance. Moreover, the protocol of incorporating nanomaterial by this post-treatment is simple and can be applied to any RO membrane after it is manufactured.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.90-93
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• 2007

The effects of the host on the aggregation behavior of Oxaxine 720 (Ox720) were studied using absorption, fluorescence, and excitation spectra. The host materials used in this study were water, ethanol, and $TiO_2/P123$ nanocomposite. Ox720 aqueous solution contains a significant amount of H-aggregates, which increases with the increase in the concentration. In ethanol solution, Ox720 mainly exists in the monomer form and tiny amount of Ox720 exists in H- and J-aggregate forms. In the $TiO_2/P123$ nanocomposite thin film, the amount of H-aggregates was smaller than that in the aqueous solution but greater than that in the ethanol solution. $TiO_2$ nanocomposite thin film was proven to be a moderately good host for Ox720.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.121-121
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• 2008

We propose a novel nanomaterial-based pn diode which constructed with an n-type ZnO nanowire (NW) and a p-type HgTe nanoparticle (NP) thin film. The photo current characteristics of a ZnO NW, a HgTe NP thin film and pn diode constructed with a ZnO NW and a HgTe NP thin film were investigated under illumination of the 325 nm and 633 nm wavelength light. The conductivities of a ZnO NW exposed to the 325 nm and 633 nm wavelength light increased, while the photocurrents taken from the HgTe NP thin film was very close to the dark currents. Moreover, The pn diode exhibited the rectifying characteristics of the dark current and of the photocurrent excited by the 633 nm wavelength light. In contrast, the ohmic characteristics for the photocurrent were observed due to the junction barrier lowering in the conduction band of the ZnO nanowire under the illumination of the 325 nm wavelength light.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.34-40
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• 2013

Various depositional conditions, such as substrate, pressure, deposition time, temperature of substrate, power and gas composition, have mainly been studied to attain DLC films using RF sputtering system up to the current. In this study, the $N_2/Ar/CH_4$ gas mixture factored on characteristics of DLC deposited film such as structure, hardness, electrical property were investigated. The concentration of the $N_2$ gas in the sputtering gas may be a significant effect on the growth rate of the doped films, because nitrogen ions react not only with the carbon atoms on the target but also with $C_xH_y$ ions in the plasma on the substrate surface. It was seen from this experimental that the resistance of deposited film is decreased, and the relative intensity ratio of D to G peak is increased as nitrogen content of film deposition is increased.

• Composites Research
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• v.26 no.4
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• pp.254-258
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• 2013

Polypropylene films reinforced with multi-walled carbon nanotubes and exfoliated graphite nanoplatelets were fabricated by extrusion, and the effects of filler type and take-up speed on the mechanical properties and microstructure of composite films were investigated. Differential scanning calorimetry revealed that the addition of carbon nanomaterials resulted in increased degree of crystallinity. However, increasing the take-up speed reduced the degree of crystallinity, which indicates that tension-induced orientations of polymer chains and carbon nanomaterials and the loss of degree of crystallinity due to rapid cooling at high take-up speeds act as competing mechanisms. These observations were in good agreement with tensile properties, which are governed by the degree of crystallinity, where the C-grade exfoliated graphite nanoplatelet with a surface area of $750m^2/g$ showed the greatest reinforcing effect among all types of carbon nanomaterials used. Scanning electron microscopy was employed to observe the carbon nanomaterial dispersion and orientation, respectively.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.308-318
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• 2022

The surface modification and treatment using thermal plasma were reviewed in academic fields. In general, thermal plasma is generated by direct current (DC) and radiofrequency (RF) power sources. Thermal spray coating, a typical commercial process using thermal plasma, is performed by DC thermal plasma, whereas other promising surface modifications have been reported and developed using RF thermal plasma. Beyond the thermal spray coating, physical and chemical surface modifications were attempted widely. Superhydrophobic surface treatment has a very high industrial demand particularly. Besides, RF thermal plasma system for large-area film surface treatment is being developed. Thermal plasma is especially suitable for the surface modification of low-dimensional nanomaterial (e.g., nanotubes) by utilizing high temperature and rapid quenching. It is able to synthesize and modify nanomaterials simultaneously in a one-pot process.

• Membrane Journal
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• v.26 no.5
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• pp.351-364
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• 2016

In recent decades, many researchers have tried to improve desalination performances of polyamide (PA) thin-film composite membranes (TFCs) by incorporating nanomaterials into a selective PA layer. This review focuses on PA-based nanocomposite membranes with high performances for energy-effective desalination in reverse osmosis. Carbon based nanomaterial (e.g., graphene oxide (GO), carbon nanotubes (CNT)) and/or other nanoparticles (e.g., zeolite, silica and etc.,) were applied to overcome the trade-off correlation between water permeability and salt rejection of current polymeric desalination membranes. Here, this brief review will discuss current studies of PA-based nanocomposite membranes with enhanced separation characteristics and provide the future research direction to achieve further improved desalination performances.

• Smart Media Journal
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• v.12 no.5
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• pp.36-45
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• 2023

Recently, in digital agriculture, the types and utilization of greenhouses based on IoT are spreading, and greenhouses are being modernized, enlarged, and even factoryized using smart technology. However, a specific standardization plan has not been proposed according to the equipment for data collection in the smart greenhouse and the size or shape of the greenhouse. In other words, there is a lack of standard data for facility equipment, such as the type and number of sensors and equipment according to the size of the greenhouse, the type of greenhouse construction film and materials suitable for crops and carbon neutrality. Therefore, in this study, the suitability of the implementation, installation and quantity of IoT equipment for data collection was tested, and some standard technologies were presented through the implementation of data collection and communication methods. In addition, impact strength, tensile, tear, elongation, light transmittance, and lifespan issues for PE, PVC, and EVA, which account for about 90% of existing greenhouses, were presented, and the shape, size, and environmental problems of greenhouses made of films were presented. presented in the text. In this research paper, a standardized carbon-neutral modular smart greenhouse using nano-material film was implemented as a solution to environmental problems such as greenhouse size, farm crop type, greenhouse lifespan, and film, and its performance with existing greenhouses was analyzed and presented. Through this, we propose a modularized greenhouse that can be expanded or reduced freely without distinction in the size of the greenhouse or the shape of farmhouse crops, and the lifespan is extended and standardized. Finally, the average characteristics of greenhouses using existing PE, PVC, and EVA films and the characteristics of greenhouses using new carbon-neutral nanomaterials are compared and reviewed, and a plan to implement an expandable IoT greenhouse that supports carbon neutrality is proposed.