• Korean Journal of Materials Research
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• v.22 no.4
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• pp.207-210
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• 2012

The preparation of $Sm_2O_3$ doped $CeO_2$ in Igepal CO-520/cyclohexane reverse micelle solutions has been studied. In the present work, we synthesized nanosized $Sm_2O_3$ doped $CeO_2$ powders by reverse micelle process using aqueous ammonia as the precipitant; hydroxide precursor was obtained from nitrate solutions dispersed in the nanosized aqueous domains of a micro emulsion consisting of cyclohexane as the oil phase, and poly (xoyethylene) nonylphenylether (Igepal CO-520) as the non-ionic surfactant. The synthesized and calcined powders were characterized by Thermogravimetry-differential thermal analysis (TGA-DTA), X-ray diffraction analysis (XRD), and Transmission electron microscopy (TEM). The crystallite size was found to increase with increase in water to surfactant (R) molar ratio. Average particle size and distribution of the synthesized $Sm_2O_3$ doped $CeO_2$ were below 10 nm and narrow, respectively. TG-DTA analysis shows that phase of $Sm_2O_3$ doped $CeO_2$ nanoparticles changed from monoclinic to tetragonal at approximately $560^{\circ}C$. The phase of the synthesized $Sm_2O_3$ doped $CeO_2$ with heating to $600^{\circ}C$ for 30 min was tetragonal $CeO_2$. This study revealed that the particle formation process in reverse micelles is based on a two step model. The rapid first step is the complete reduction of the metal to the zero valence state. The second step is growth, via reagent exchanges between micelles through the inter-micellar exchange.

• Korean Journal of Human Ecology
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• v.21 no.4
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• pp.781-790
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• 2012

In midst of growing interest and awareness towards sustainability and being "green", there has been increased demand for sustainable clothing. In the purpose of boosting eco-friendly textiles industry, this research was conducted by investigating environmentally-conscious clothing behavior of university students and assessing their views on eco-friendliness of fibers. Thus, their awareness on recycled polyester fiber was evaluated. The research was conducted by surveying 257 university students residing in Daejeon. The data were analyzed with descriptive statistics, factor analysis, and reliability analysis, using SPSS 19.0. The results were as follows. 1) The majority of the subjects answered "Disposing clothing in the clothing recycling container" to reduce environmental impact. 2) Six factors of eco-friendliness of fiber were extracted as reutilization, unfinishedness, economics, environment preservation, natural materials, and slow fashion by using factor analysis. 3) Subjects scored organic cotton as most eco-friendly among various fibers. Recycled polyester fiber was graded less sustainable than natural fiber, but more eco-friendly than artificial one. 4) In assessment of subject's awareness of recycled polyester fiber, they highly valued on resource-reutilization and economics, but less valued on its hygiene, thermal insulation and health-functionality.

• Journal of the Korean Society of Clothing and Textiles
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• v.42 no.1
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• pp.172-182
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• 2018

The purpose of the present study was to quantify the thermal insulation of garments by item and examine factors influencing clothing insulation. A total of 769 garments in clo unit were collected and classified into 12 categories: blouses/shirts (95 items, BS), T-shirts/sweaters (62 items, TS), vest (23 items, VT), cardigans (23 items, CD), jackets/coats (75 items, JC), sport outerwear (including padding jackets)(48 items, SO), trousers (23 items, TR), skirts (56 items, SK), dresses (28 items, DS), underwear (150 items, UW), sleepwear (50 items, SW), and personal protective clothing (59 items, PPC). The results showed that clothing insulation was $0.21{\pm}0.01clo$ for the BS, $0.22{\pm}0.01clo$ for TS, $0.12{\pm}0.00clo$ for VT, $0.23{\pm}0.02clo$ for CD, $0.40{\pm}0.02clo$ for JC, $0.49{\pm}0.03clo$ for SO, $0.21{\pm}0.01clo$ for TR, $0.18{\pm}0.01clo$ for SK, $0.34{\pm}0.03clo$ for DS, $0.09{\pm}0.01clo$ for UW, $0.42{\pm}0.03clo$ for SW, and $0.56{\pm}0.03clo$ for PPC (p<.001). The most influential factors among the seven factors for thermal insulation of garments were clothing weight and covering area; however, the explanatory powers of two factors differed according to clothing categories. The covering area had more significant impact on clothing insulation in cardigans, jackets/coats, trousers, and dresses than clothing weight. Covering areas and clothing weight were the most influential factors in the following categories: blouses/shirt, T-shirts/sweaters, skirts, sleepwear and personal protective clothing. The garment weight was the most important factor for thermal insulation for the sport outerwear.

• Nuclear Engineering and Technology
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• v.18 no.3
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• pp.200-208
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• 1986

The loss of coolant accident based on a double-ended cold leg break is analyzed with the discharge coefficient (Ca) of 0.4. This analysis covers the whole transient period from the start of depressurization to the complete refilling of the core by using RELAP4/MOD6-EM and RELAP4/ MOD6-HOT CHANNEL for the system thermal-hydraulics and the fuel performance during the blowdown phase respectively, and RELAP4/MOD6-FLOOD and TOODEE2 during the reflood phase. A simple analytical method has been developed to account for the lower plenum filling by approximating steam-water countercurrent flows and superheated wall effects at the downcomer during the refill period. Based on the informations. at the time of EOB (end-of-bypass), the refill duration time and the initial reflooding temperature were estimated and compared with the results from the RELAP4/MOD6, resulting in a good agreement. In addition, some parametric studies on the EOB were performed. The form loss coefficient between upper head and upper downcomer was found to be sensitive to the occurrence of the spurious EOB. Appropriate form loss coefficients should be taken into account to avoid the flow oscillations at the downcomer. The analyses with the six and three volume core nodalizations, respectively, show much similar trends in the system thermal-hydraulic performance, but the former case is recommended to obtain good results.

• International Journal of Advanced Culture Technology
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• v.6 no.2
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• pp.129-136
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• 2018

Our present study, we impregnated Al-Fe-Mg-Si (NFM) nanocomposites having various concentrations 0, 1000, 3000, and 5000 mg/L in biomass in order to make carbonized biomass. We characterized the properties of the impregnated samples through thermogravimetric/differential thermal analysis (TG-DTA), pore distribution, scanning electron microscopy (SEM). The best results were observed for a NFM nanocomposites concentration of 5000 mg/L. After the first heat treatment, carbonization, and activation processes, the fixed carbon ratio and iodine adsorptivity were increased by 21.89% and 368 mg/g, 23.98% and 475 mg/g, 26.40% and 238 mg/g, respectively. The remove rate of malodorous and VOCs were that the sample shows good removal capabilities. From above results, our sample could be used for the removal of noxious and malodorous gases and for the purification of wastewater.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.1
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• pp.90-96
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• 2009

Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. Today, injection molded parts have been increased dramatically the demand for high strength and quality applications. This report investigates that the optimum injection molding condition for minimum of shrinkage. Molding shrinkage is occurred by several reasons such as thermal shrinkage, a hardening process and compressibility. This report concentrate on shrinkage by a hardening process. As Change a holding pressure and holding time, checked deflections of X, Y, Z directions by shrinkage based on same condition. In conclusion, it was found that holding pressure is stronger and holding time is longer, the deflection by shrinkage is smaller because injection molding needs enough time for cooling and high density. The FEM Simulation CAE tool. Moldflow, is used for the analysis of injection molding process.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.2
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• pp.395-402
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• 2001

The gasoline engine tends to high performance, fuel economy, small-sized. Therefore, it is necessary to solve the problems on thermal load, abnormal combustion, etc, in the engine, Thine film instantaneous temperature measurement probe was made. And the manufactural method of probe was established. The instantaneous surface temperatures in the constant volume combustion chamber were measured by this probe and the heat flux was obtained by Fourier analysis. The authors measured the wall temperature of combustion chamber and computed the heat flux through the cylinder wall in order to understand the combustion characteristics depending on height of probe. For achieving this goal, the thin film instantaneous temperature probe was developed for analyzing the instantaneous surface wall temperature and unsteady heat flux on the constant volume combustion chamber.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.3
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• pp.588-594
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• 2001

The aim of this paper is to develop the low temperature vacuum dryer, with low initial investments and operating costs, easy operating method and trouble-free operation Usally operations just below atmospheric pressure, as with direct dryers, but some are built for vacuum operation with pressure as low 50 mmHg abs. The lowers the boiling point to $39^{\circ}C$ The experimental data of quantitative analysis for using practically were obtained by the constant drying rate period and reducing drying rate period according to the temperature of hot water which is the experimental parameters of present experiment. As the results, it took about 20 hours for material to reach about 18% of the final moisture content is order to store products for a long time about 450% of the early moisture content at the beginning of drying and maximum drying rate comes to about 0.30 kg/m2hr at about 350% of the moisture content.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.5
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• pp.624-632
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• 2003

In the gasoline engine industry. there has been a trend towards the development of high performance engines with improved fuel efficiency, reduced weight and smaller sizes. These trends help to solved engine problems related to thermal load and abnormal combustion. In order to investigate these Problems, a thin film-type probe for instantaneously measuring temperatures has been suggested. A method for manufacturing such a probe was established in this study. The instantaneous surface temperature of a constant volume combustion chamber was measured by this probe and the heat flux was obtained through Fourier analysis. A peak instantaneous temperature was obtained after 55∼60 ms from ignition and the temperature increased according to an equivalence ratio and varied differently according to the position of the probe. Total heat loss during combustion period was affected by the equivalence ratio and differed widely in accordance to the position of the probe.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.134-139
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• 2002

Motorcycle industry, for its competitive position, depends on part design technology. This part design has a bulky amount of data and asks the accumulation of advanced technical skill and experience, and fragmentary technical application is not enough to get to the kernel of a problem. Therefore, the improvement of proper productivity - the starting point of engineering design - and useful Design Methodology for products manufacturing are needed. Thus this paper is aimed to create a program that outputs dynamic characteristics of a vehicle when the data from fully understanding on motorcycle's brake system and induced formula for brake design are inputted.