• Korean Journal of Materials Research
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• v.11 no.8
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• pp.679-684
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• 2001

The surface of natural graphite has not only good electrical conductivities and lubrication properties but also has strong hydrophobicity. There are no functional groups and chemical properties on it. It is difficult to join with any other ions and to disperse in aqueous system. In order to increase dispersion ability throughout modification of surface property, it is necessary to let graphite have some function on its surface by the adsorption of surfactant molecules. In this study, using zeta potential adsorbed surfactant molecules(ABDM) on graphite surface and its surface Properties turn hydrophobic into hydrophilic. The dispersing mechanism of graphite particles in aqueous system has been explained using the DLVO theory, It is concluded that the high dispersable graphite suspension of which dispersing stability$(T_{1/2})$ is 44.5 hours at pH 10 and 22.5mV zeta potential can be produced.

• KSBB Journal
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• v.31 no.4
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• pp.256-262
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• 2016

The need for natural cosmetic ingredients has been increasing over the world nowadays. Agarose, a natural polymer from red seaweeds, has high hydrophilic character and a function of scaffolder. As skin moisturizer, agarose is adequate for percutaneous absorption. While, blueberry fruits extract possesses rich procyanidins and anthocyanins which show health benefits, anti-oxidant effect, anti-aging and anti-melanogenesis. Stability, sensory preference, skin trouble of the emulsion formula are important for cosmetic product development. In this study, we manufactured an emulsion formula for skin moisturizers using the two ingredients and tested emulsion stability and skin trouble. Total phenolic contents of the blueberry fruits extract were evaluated as well as tyrosinase inhibitory and collagenase inhibitory activities. $IC_{50}$ values of blueberry fruits extract for anti-tyrosinase and anti-collagenase activities were 168 and $112{\mu}g/mL$, respectively using gallic acid as a control ($64.8{\mu}g/mL$). The stability (pH and viscosity) of the formula containing 2% blueberry fruits extracts and 0.1% agarose was measured at five different temperatures (room temp., $25^{\circ}C$, $55^{\circ}C$, $45^{\circ}C$, $55^{\circ}C$) under the sun light at 2 day intervals for 12 days. There has been little pH change at the different temperatures. According to the sensory evaluation, there was no significant flavor, discoloration and physical changes of the formula at $25-65^{\circ}C$. These results suggest that emulsion formula containing blueberry extract and agarose could be used as a candidate for lotion and essence products.

• Journal of Environmental Health Sciences
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• v.39 no.4
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• pp.360-368
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• 2013

Objectives: Phthalates are used in a large variety of products including as coatings of pharmaceutical tablets, film formers, stabilizers, dispersants, emulsifying agents, and suspending agents. They have been the subject of great public concern in recent years. The extensive uses of this material have attracted attention and issues regarding its safety have been raised. Methods: In this study, three types of phthalate skin permeation were studied using matrixes such as ointments, creams and lotions in vitro. The absorption of phthalate diesters [Dimethyl phthalate (DMP), Di-n-propyl phthalate (DPP) and Di-n-pentyl phthalate (DNPP)] using film former has been measured in vitro through rat skin. Epidermal membranes were set up in Franz diffusion cells and their permeability to PBS measured in order to establish the integrity of the skin before the phthalates were applied to the epidermal surface. Results: Absorption rates for each phthalate ester were determined and permeability assessment made to quantify any irreversible alterations in barrier function due to contact with the esters. Types of phthalate in vitro experimental results quickly appeared in the following order DMP > DPP ${\geq}$ DNPP. Conclusions: In the experimental results, lotion> cream> ointment, and the permeation rate of lotion with a great amount of moisture was the fastest. Skin permeation rate is generally influenced by the chemical characteristics of a given chemical, such as molecular weight and lipophilicity. As the esters became more lipophilic and less hydrophilic, the rate of absorption decreased.

• Journal of Adhesion and Interface
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• v.3 no.3
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• pp.7-14
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• 2002

Modified polyethylenes with polar side groups of -COOK, $-CONH_2$, and -COOH were prepared at a dispersion state in water by reacting poly(ethylene-co-methylacrylate) (PEMA) with aqueous solution of KOH and ammonia. Types and their contents of side groups were investigated by infrared spectroscopy, elemental analysis and atomic absorption analysis. Solution viscosity and surface tension were also measured as a function of solid contents. Stability and transparency of the dispersions were greatly affected by the content of COOK in the side groups. The stable dispersion could be prepared at a composition of COOK of 20 mole% at least. The transparency was increased with increasing the COOK contents, but decreased with increasing the amide content at a constant composition of COOK. Solution viscosities increased abruptly at a lower solid content when the COOK contents were increased, implying higher entanglement between the chains in dispersions with higher content of hydrophilic COOK group. The dispersions of higher COOK content revealed lower surface tension values.

• Polymer(Korea)
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• v.27 no.6
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• pp.555-561
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• 2003

The self-assembled monolayer coating of octadecyltrichlorosilane (OTS) on the silicon based MEMS was investigated and surface characteristics were considered as a function of coating conditions and reagent composition. The sulfuric peroxide mixture (SPM) solution was used to form -OH group which caused the hydrophilic characteristic on silicon surftce. Highest hydrophilicity was obtained by SPM solution with 85% acid content at room temperature. OTS was applied on the silicon surface by means of self-assembled monolayers (SAMs) coating. It was found that sol-gel reaction was took place between -OH group on the silicon surface and -Cl group in OTS. As a result, the contact angle increased due to the increase of hydrophobicity by Si-O bonding of SAMs. Sol-gel reaction could be controlled by coating conditions as well as reagent composition in OTS coating solution.

• Journal of the Korean Applied Science and Technology
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• v.40 no.1
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• pp.71-80
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• 2023

Silver paste is a valuable electrode material for electronic device applications because it is easy to handle with relatively low heat treatment. This study treated the electrode surface using an atmospheric-pressure plasma jet on the silver-paste electrode. This plasma jet was generated in an argon atmosphere using a high voltage of 5.5 to 6.5 kV with an operating frequency of 11.5 kHz. Plasma-jet may be more beneficial to the printing process by performing it at atmospheric pressure. The electrode surface becomes hydrophilic quickly and contact angle variation is observed on the electrode surface as a function of plasma treatment time, applied voltage, and gas flow rate. Also, there was no deviation in the contact angle after the plasma treatment in the large-area sample, that means a uniform result could be obtained regardless of the substrate size. The outcomes of this study are expected to be very useful in forming a stacked structure in the manufacture of large-area electronic devices and future applications.

• Journal of Wetlands Research
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• v.26 no.1
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• pp.114-125
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• 2024

Wetlands in the living area are important ecological resources that are the basis for the daily life or farming activities of local residents, and have high ecological value such as ecosystem services and green infrastructure. This study was carried out to develop a functional evaluation methodology optimized for small-scale wetlands(RAMS). Based on on-site evaluation by experts, surveys and in-depth interviews, four functional items, including biodiversity, health, hydrophilic culture and ecology, water circulation, and carbon absorption, and 15 detailed indicators, and the evaluation grade for each detailed indicator, were developed on a 5-point scale. The evaluation methodology optimized for small-scale living areas wetlands (RAMS) proposed as a result of this study can be used as basic data for conservation and restoration and management of small-scale living areas wetlands at home and abroad.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.1
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• pp.25-35
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• 2017

The purpose of this study is to re-exam of the modern values of a moat to utilize it with various functions such as a military defense on the outskirts of the castle, dividing the space by its boundary, controlling the micro-climate in the worsening modern environment with temperature rise due to climate change and habitat reduction of animals, and providing the habitat of animals to modern urban space, etc. The scope of the study is focusing on the castles with the moat installed to prevent the enemy from accessing directly to the wall using a pond or water path for military defense on the outskirts of the castle or to divide it into boundaries. In the Orient, the Nakan Eupseong, Haemi Eupseong, Gyeongju Wolseong in Korea and the Forbidden City in China, and Nijo Castle and Osaka Castle in Japan were selected. In the West, Edinburgh Castle in Britain, Blois Castle in France, Chillon Castle in Switzerland, and Frederiksborg Castle in Denmark were selected for the study. As a research method, literature research and field research were conducted. For the Orient, it was conducted in parallel with the literature research and field research. For the western, it was mainly conducted with literature research. For the literature research, the origin of the moat, the concept of the moat, the function of the moat, the history and culture of the western moat are based on the data from the related institutions and previous studies. For the Orient field research, exploring was conducted in two to three times from Jan. 2016 to Dec. 2016 in each of the target areas of Nakan Eupseong, Haemi Eupseong, Gyeongju Wolseong in Korea and the Forbidden City in China, and Nijo Castle and Osaka Castle in Japan. The contents of the research were analyzed through interviews, photographs, measurements, and observations on the function, size, and characteristics of the moat of each target. The results of this study are as follows. The moat was a structure installed to set a boundary for military defense facilities on the outskirts of a castle and it played an important role as a part of the city in the ancient times of Asia and the West through the Middle Ages. The role of the moat is gradually disappearing due to the disappearance of the purpose of military defense. However, moats are excluded from modern landscape planning, despite the fact that a moat filled with water is a hydrophilic space with great historical and cultural value such as various cultural activities and providing habitats for animals. By reflecting on the moats various functions in modern cities and utilizing it, it is expected to be utilized to bring pleasant air into the city where the circulation of air is blocked and energize the city as a hydroponic element.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.481-489
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• 2017

The study area,Cheonan Stream, is an urban river that flows through urban areas in close proximity to densely populated areas and multi-use facilities. The natural river improvement project from 2006 to 2015 improved the quality of life of local residents with the improvement of river function, the restoration of the natural ecosystem and the securement of hydrophilic space. A bike way in the constructed waterside space was built focusing on trails. This study suggests improvements appropriate for insufficient bike way function-related regulations. The problems of ramps, river crossing facilities, stairway facilities, safety facilities, signs, road markings, and parking facilities, etc.have arisen in the utilization situation and citizen consciousness survey. As an improvement, it was suggested that 12% or fewer ramps should be improved, a submerged bridge should be installed at 7 places separated by stepping bridges, and signs and road markings according to bike way-related regulations should be installed and bike parking facilities at Cheonan station and Cheonan bus terminal should be expanded. The bike way in the waterfront of ChoenanCheon(river) will increase the accessibility and utilization rate of short-distance transportation with the institutional expansion of bike use facilities and work organizations and the improvement of facilities in accordance with urban rivers and bike-related regulations. Therefore, it is expected that the development of the living space will be beneficial for the citizens due to the elimination of traffic in the city and the activation of bike traffic.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.1
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• pp.75-82
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• 2012

Natural moisturizing factors (NMFs) are hydrophilic and water-soluble components in stratum corneum of the skin. NMFs absorb water from outer environment and enhance the water-holding capacity of stratum corneum and thereby, prevent the dryness and increase flexibility and plasticity of skin. NMFs are mainly composed of amino acids and their metabolites that are produced from the degradation of filaggrin. Here we established a simultaneous quantification method for 22 amino acids in tape-stripped stratum corneum samples using UPLC-PDA. With this method, we analyzed amino acid contents from tape-stripped stratum corneum samples of forearm and forehead regions from 15 healthy volunteers. Amino acid contents of inner (or upper) region were higher than outer (or lower) region of stratum corneum. Amino acid contents of stratum corneum of forearm were higher by 1.5 fold than forehead region. Of note, total amino acid contents were significantly and inversely correlated with trans-epidermal water loss (TEWL), an index for skin barrier function. Especially, Ser, Glu, Gly, Ala and Thr were determined to positively affect skin mositurizing activities. In conclusion, we could demonstrate that amino acid contents of stratum corneum are closely linked with skin barrier and moisturizing function, providing an important and fundamental methodology for the study of amino acids in skin physiology.