• Proceeding of Spring/Autumn Annual Conference of KHA
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• 한국주거학회 2009년 춘계학술발표대회 논문집
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• pp.264-267
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• 2009

Today, our lifestyle and residential culture has been changed have been changed by interchange with various countries in various sides. In order to become an internationally recognized residential environment designer in this environment, we must understand the housing viewpoint of residents in a country first. Therefore, this study was intended to obtain useful material for residential environment design of both countries by comparing the housing viewpoint between Chinese students studying in Korea and Korean students. A questionnaire was conducted on 205 Korean students and 193 Chinese students (Korean race) from Y University in random sampling basis. The result is as follows. First, both Korea and China have a higher ratio of apartments in both current and previous types of house. But, both Korea and China have similar ratios between detached house and apartment for a desired type of house at the time of moving in. Second, Korean and Chinese university students consider and as the most important functions of residence, and Chinese university students consider more functions of residence than Korean students. Third, both Korean and Chinese consider a living room as the most important space among housing spaces, but Chinese consider a private room more importantly than Korean. Fourth, overall satisfaction rate of Korean students for current houses was average, and most Chinese students were generally satisfied with their houses.

• KIEAE Journal
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• 제16권3호
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• pp.83-88
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• 2016

Purpose : This study aimed to verify the surface hardness and water repellency of earth paint manufactured with earth, a natural material, and provide the results as basic data for paint made with natural materials. Method : After presenting the accurate manufacturing methods for basic materials for paint, the authors conducted and analyzed experiments to evaluate surface hardness and water repellency, fundamental performance indicators for paint, based on different mixture ratios. From the results of the experiment to assess the surface hardness of flour-based earth paint, we observed high surface hardness only after painting the specimen three times. Since potato starch-based earth paint has higher viscosity than its flour-based counterpart, the former did not paint well on the first occasion, resulting in low surface hardness. After painting two or more times, however, it was observed to have higher surface hardness than flour-based earth paint. Result : It was found that at least three iterations of painting was required to obtain high surface hardness of potato starch-based earth paint. Furthermore, the results of the water resistance experiment of earth paint suggest that the use of environment-friendly finishing materials coupled with boiled linseed oil will mitigate the drawbacks of earth paint. The experiment with one-year-old specimens also demonstrated similar water repellent characteristics, which indicates that the performance will improve once the paint has dried for a sufficient period of time.

• Journal of Hydrogen and New Energy
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• 제23권1호
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• pp.34-42
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• 2012

Gas diffusion layers (GDLs) of carbon composite type in polymer electrolyte fuel cells were prepared by simple and cheap manufacturing process. To obtain the carbon composite GDLs, carbon black with polymer binder was mixed in solvent, rolled to make sheet, and finally heat-treated at $340^{\circ}C$. The performance of fuel cell using composite GDLs was changed by PTFE content. The physical properties of composite GDLs for pore, conductivity and air permeability were analyzed to compare with the variation of fuel cell performance. The conductivity of composite GDLs was very similar to carbon paper as commercial GDL but pore properties and air flux were considerably different. The porosity, PTFE content and conductivity for composite GDLs did not have an influence on the cell performance much. The increase of pore diameter and air flux led to enhance cell performance.

• Electrical & Electronic Materials
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• 제7권2호
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• pp.138-144
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• 1994

Electrical conduction phenomena of $C_{22}$-quinolium(TCNQ) Langmuir- Blodgett(LB) films are reported through a study of current-voltage(I-V) characteristics along a perpendicular direction. The I-V characteristics were investigated by applying a step or a pulse voltage to the specimen as well as changing temperatures in the range of 20-250[.deg. C] It show an ohmic behavior in low-electric field, and a nonohmic behavior in high-electric field. This nonohmic behavior has been interpreted in terms of a conduction mechanism of space-charge limited current and Schottky effect. When the electric field is near the strength of 10$_{6}$ V/cm, there occur anomalous phenomena similar to breakdown. When step or pulse voltage is applied, the breakdown voltage shifts to the higher one as the step or pulse time width becomes shorter. To see the influence of temperature, current was measured as a function of temperature under the several bias voltages, which are lower than that of breakdown. It shows that the current increases to about 103 times near 60-70[.deg. C], and remains constant for a while up to around 150[.deg. C] and then suddenly drops. We have also performed a DSC(differential scanning calorimetry) measurement with $C_{22}$-quinolium(TCNQ) powder in the range of 30-300[.deg. C]. These results imply that the anomalous phenomena occuring in the high electric field are caused by the electrical and internal thermal effect such as a joule heating.ating.

• Journal of the Korean Ceramic Society
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• 제47권6호
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• pp.598-602
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• 2010

When metal oxides are added into crystalline glaze, colors of glaze and crystals are similar as colorants generally. But the case of NiO in zinc crystalline glaze is different from general color development. When NiO is added to zinc crystalline glaze it can develop two or three colors. The active use of color development mechanism by adding NiO to the zinc crystalline glaze to control color of the base glaze and crystal with stability is investigated. This report is expected to contribute to the ceramic industry in improving application of zinc crystalline glaze. For the experiment of NiO, the quantity of NiO additives is changed to the base glaze for the most adequate formation of willemite crystal from previous research and firing condition: temperature increasing speed $5^{\circ}C/min$, holding 1 h at $1270^{\circ}C$, annealing speed $3^{\circ}C/min$ till $1170^{\circ}C$, holding 2 h at $1170^{\circ}C$ then naturally annealed. The samples are characterized by X-ray diffraction (XRD), UV-vis, and Micro-Raman. The result of the procedure as follows; Ni substitutes for Zn ion then glaze develops blue willemite crystals, as if cobalt is used, on brown glaze base. When NiO quantity is increased to over 5 wt%, willemite size is decreased, and the density of the crystal is increased, at the same time $Ni_2SiO_4$ (olivine) phase, the second phase, has been developed. The excessive NiO is reacted with silicate in the glass then developed green $Ni_2SiO_4$ (olivine), and quantity of $Ni_2SiO_4$ (olivine) is increased as quantity of willemite is decreased. It is proved to create three colors, blue, brown and green by controlling the quantity of NiO to the zinc crystalline glaze and it will improve the multiple use of colors to the ceramic design.

• Journal of the Korea Convergence Society
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• 제10권12호
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• pp.293-298
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• 2019

The global market for temperature sensors for power plants is estimated at around 35 billion won, of which South Korea relies on imported products for more than 95 percent. This study is that a temperature measurement device for gas turbine rotators for power plants and can be applied to more than 800 of 100 MW gas turbine generators operating in Korea. This study has improved durability by changing the shape of the measuring part, structure of the connecting part, and material changes, and is a component technology applicable to other measuring devices such as humidity, gas and hydraulic pressure used in precision chemical process and plant export industry. As a result of this study, temperature sensors designed as three types of sensors for measuring the temperature of the gas turbine for power plants met Class 1 temperature accuracy in the range of 0℃ to 300℃, and improved durability significantly compared to similar products.

• Journal of the Korean Society of Fashion and Beauty
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• 제3권3호
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• pp.64-70
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• 2005

The purpose of this study was to give help for more activation to the area of spa industry appropriate to the emotion of our country based on the spa of recognition of massage specialist. Aroma Essencial oil bath was the first favorite of the customers when they're going to have bath in Hydro-therapy or with some other material in their bathtub according to the general results of the previous study. The most high voice of discontent of customers was the high price and the main customer's ages on the spa-therapy were the ages 30s and 40s. The method for activation for future spa-therapy were showed as the better facilities and advertising, reasonable price, systematic education programs, professionalists as an order. The proper care hours for spa-therapy that customers like most was 1:30-2:30 and the resonable price of one time care of that was shown as 100,000-200,000 won. The priority actions for the competition with foreigners on this area of spa-therapy will be the various and nation-wide advertisement of the effectiveness on spa-therapy to the customers to use easily and to be made being generalized on their lives. And the our inland spa-therapy must have main position at the center of cities, the various programs to satisfy the Korean traditional culture of them should be studied and introduced. And at that time future inland spa-therapy industry will have power for the competitions with similar foreign industries.

• Journal of the Korean Recycled Construction Resources Institute
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• 제4권1호
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• pp.19-24
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• 2016

Several researches on high volume fly ash concrete have been conducted to investigate its fundamental material properties such as slump, strength and durability and however, research on the structural behavior of bond strength is essential for the application of this high volume fly ash concrete to structural members because of the necessity of reinforcement. But the exact design code for application and researches on the bond behavior of high volume fly ash concrete lack yet. To achieve such a goal, this paper evaluates experimentally the bond behavior of high volume fly ash concretes by direct pull-out test and compares between the current test results and existing research results. By the test results, it is shown that the bond behavior of high volume fly ash concrete is similar to that of general concrete. And by the comparison between test and existing research, it is shown that bond stress of high volume fly ash concrete is underestimated, as the embedment length gets longer.

• The Journal of Korean Academy of Prosthodontics
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• 제46권6호
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• pp.553-560
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• 2008

STATEMENT OF PROBLEM: Proximal contact plays an important role in the stability and maintenance of the integrity of the dental arches. However, it is difficult to evaluate quantitatively the tightness of proximal tooth contact (TPTC). PURPOSE: The aim of this study was to measure the TPTC in permanent dentition. MATERIAL AND METHODS: Ten young adult volunteers with healthy dentition participated in this experiment. The TPTC between the teeth of both the maxilla and the mandible was measured at rest state by a novel device which records the TPTC by pulling of a stainless steel strip (0.03 mm thick) using the electric motor. One-way ANOVA test was used to compare the values in all measured area. When a statistically significant difference was calculated, Bonferroni correction was applied. Independent samples t-test was used to compare the values in male and female. RESULTS: The lowest TPTC and the highest TPTC was measured between the lower central incisors (0.87 ${\pm}$ 0.20 N), and between the lower left first molar and second molar (1.99 ${\pm}$ 0.68 N), respectively. All TPTC per quadrant demonstrated a similar pattern of a continuous increased gradient in an anterior-posterior direction. There are no significant difference between the maxilla and mandible. CONCLUSION: The TPTC was measured quantitatively by a novel device and decreased progressively in a posterior-anterior direction.

• The Journal of Advanced Prosthodontics
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• 제10권2호
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• pp.147-154
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• 2018

PURPOSE. This study was performed to evaluate the osteogenic potential of 3mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) and niobium oxide containing Y-TZPs with specific ratios, new (Y,Nb)-TZPs, namely YN4533 and YN4533/Al20 discs. MATERIALS AND METHODS. 3Y-TZP, YN4533 and YN4533/Al20 discs (15 mm diameter and 1 mm thickness) were prepared and their average surface roughness ($R_a$) and surface topography were analyzed using 3-D confocal laser microscope (CLSM) and scanning electron microscope (SEM). Mouse pre-osteoblast MC3T3-E1 cells were seeded onto all zirconia discs and evaluated with regard to cell attachment and morphology by (CLSM), cell proliferation by PicoGreen assay, and cell differentiation by Reverse-Transcription PCR and Quantitative Real-Time PCR, and alkaline phosphatase (Alp) staining. RESULTS. The cellular morphology of MC3T3-E1 pre-osteoblasts was more stretched on a smooth surface than on a rough surface, regardless of the material. Cellular proliferation was higher on smooth surfaces, but there were no significant differences between 3Y-TZP, YN4533, and YN4533/Al20. Osteoblast differentiation patterns on YN4533 and YN4533/Al20 were similar to or slightly higher than seen in 3Y-TZP. Although there were no significant differences in bone marker gene expression (alkaline phosphatase and osteocalcin), Alp staining indicated better osteoblast differentiation on YN4533 and YN4533/Al20 compared to 3Y-TZP. CONCLUSION. Based on these results, niobium oxide containing Y-TZPs have comparable osteogenic potential to 3Y-TZP and are expected to be suitable alternative ceramics dental implant materials to titanium for aesthetically important areas.