• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.105-105
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• 2016

Recently, high power impulse magnetron sputtering (HIPIMS) has attracted considerable attentions due to its high potential for industrial applications. By pulsing the sputtering target with high power density and short duration pulses, a high plasma density and high ionization of the sputtered species can be obtained. HIPIMS has exhibited several merits such as increased coating density, good adhesion, microparticle-free and smooth surface, which make the HIPIMS technique desirable for synthesizing hard coatings. However, hard coatings present intrinsic defects (columnar structures, pinholes, pores, discontinuities) which can affect the corrosion behavior, especially when substrates are active alloys like steel or in a wear-corrosion process. Atomic layer deposition (ALD), a CVD derived method with a broad spectrum of applications, has shown great potential for corrosion protection of high-precision metallic parts or systems. In ALD deposition, the growth proceeds through cyclic repetition of self-limiting surface reactions, which leads to the thin films possess high quality, low defect density, uniformity, low-temperature processing and exquisite thickness control. These merits make ALD an ideal candidate for the fabrication of excellent oxide barrier layer which can block the pinhole and other defects left in the coating structure to improve the corrosion protection of hard coatings. In this work, CrN/Al2O3/CrN multilayered coatings were synthesized by a hybrid process of HIPIMS and ALD techniques, aiming to improve the CrN hard coating properties. The influence of the Al2O3 interlayer addition, the thickness and intercalation position of the Al2O3 layer in the coatings on the microstructure, surface roughness, mechanical properties and corrosion behaviors were investigated. The results indicated that the dense Al2O3 interlayer addition by ALD lead to a significant decrease of the average grain size and surface roughness and greatly improved the mechanical properties and corrosion resistance of the CrN coatings. The thickness increase of the Al2O3 layer and intercalation position change to near the coating surface resulted in improved mechanical properties and corrosion resistance. The mechanism can be explained by that the dense Al2O3 interlayer acted as an excellent barrier for dislocation motion and diffusion of the corrosive substance.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.565-575
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• 2016

Wheel reprofiling is frequently conducted to remove faults such as flange wear, flat areas, and cracks that occur in railway vehicle operation. We analyzed the dynamic performances of a vehicle before and after wheel reprofiling to grasp the influence of reprofiling on the dynamic behavior of the vehicle. We measured the wheel profile of the test vehicle and conducted a running test to analyze the vibration and comfort characteristics of the test vehicle. The result of the test indicated that vibration of the test vehicle after wheel reprofiling was reduced compared to that before wheel reprofiling. And, comfort level of the test vehicle after wheel reprofiling was improved by about 3dB laterally and vertically. Consequently, the positive effect of wheel reprofiling on the dynamic performance of vehicle was verified.

• Journal of Korean Academy of Nursing
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• v.47 no.5
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• pp.651-662
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• 2017

Purpose: The purpose of this study was to evaluate the effectiveness of a sleep improvement program combined with an aroma-necklace on sleep, depression, anxiety, and blood pressure in elderly women living at home. Methods: A program consisting of a four-week (one hour per week) sleep improvement intervention plus use of an aroma-necklace, was developed based on Cox's Interaction Model of Client Health Behavior. 70 elderly women were assigned to the experimental (n=35) or control group with no intervention (n=35). Data from 62 participants (32 in the experimental and 30 in the control) were analyzed using the SPSS 21.0 program. Women in the experimental group were instructed to constantly wear the aroma necklace filled with marjoram and orange oil until the program was completed. Sleep quality, sleep duration, sleep satisfaction, depression, anxiety, and blood pressure were measured to identify the effectiveness of the program. Results: Significant group differences were found in sleep quality (t=-5.10, p<.001), sleep duration (z=-3.10, p=.002), sleep satisfaction (z=-4.13, p=<.001), depression (t=2.53, p=.015), and anxiety (z=-2.47, p=.014). No differences were found in the systolic or diastolic blood pressure. Conclusion: The results indicate that a sleep improvement program combined with an aroma-necklace was effective in improving sleep disturbances in elderly women living at home. Nurses may contribute to improving sleep among elderly women by applying this program to aged women living in various environments.

• Journal of the Korean Ceramic Society
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• v.36 no.1
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• pp.89-96
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• 1999

Manufacturing conditions of the porous alumina mold were established to overcome various limits of the gypsum mold. For the preparations of the porous alumina mold, an activated charcoal was added to the Al2O3 with the wt% variation and then mixed. The binary slurry was study dispersed based on the examination of the ESA and rheological behaviro. The cylinder type alumina mold was cast in the gyspum mold and characterized by the shrinkage rate at the variable sintering temperature and the resistance against wear. It was proper to make a sintering of the Al2O3 by the surface diffusion which was non-shrinkage sintering mechansim, and intergranular neck growed stronger while sintering was being made. We studied a sintering by three categories; 1) thermodynamic method below 1,000$^{\circ}C$, 2) kinetic method above 1,000$^{\circ}C$ and 3) combined method. In the results of the respective works, combined method was superiro to the others. The prepared Al2O3 mold had relatively high strength, low drying rate, the resistance against the acid or base and good casting behavior.

• Journal of the Korean Society of Costume
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• v.63 no.6
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• pp.127-139
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• 2013

This research is designed to provide basic data to study the life and culture of multicultural families in Korea by taking a look at the clothing behaviors and attitudes toward traditional dresses. To this end, quantitative research was conducted on Korea-Vietnam multicultural families and Korean families. The surveys of the Korean families were completed by 250 married women in Seoul, and those of Korea-Vietnam multicultural families by 104 married Vietnamese women living in Seoul, Gyeonggi-do and Incheon. The data were analyzed using frequency analysis, factor analysis, t-test, crosstabs and ${\chi}^2$-test. The findings are as follows: First, the comparison of clothing behaviors of the Korean families and the Korea-Vietnam multicultural families found that they had statistically significant differences in values towards clothes, clothes shopping orientation and clothes purchasing behaviors. The Korean women were more involved in clothes and fashion-oriented than their Vietnamese counterparts. However, the Vietnamese women in their 20s were likely to rely more on social trends than their own needs when purchasing clothes compared to their Korean counterparts. Korean families preferred to shop in department stores, while the multicultural families relied more on discount stores and outlets. Second, the comparison of the Korean families and the Korea-Vietnam families in attitudes toward their own traditional dresses and how often to wear them showed statistically meaningful differences. The Korean group had more negative attitudes toward Hanbok, the Korean traditional dresses than the Vietnamese group. The Vietnamese women showed more interest in information on Hanbok than their Korean counterparts. They also were wearing the Korean traditional dresses more often than the Korean families. In addition, the Vietnamese women showed a stronger tendency than the Korean women that they took pride in their country's traditional dresses and believed that they were beautiful.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.1-6
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• 2017

Recently, the brittle materials such as ceramics, glass, sapphire and textile material have been widely used in semiconductors, aerospace and automobile owing to high functional characteristics. On the other hand, it has the characteristics of difficult-to-cut material relative to all materials. In this study, diamond electro-deposited band-saw machine was developed to operate stably using water-coolant type through relative motion between band-saw tool and $Al_2O_3$ material. High densified $Al_2O_3$ material was manufactured by spark plasma sintering method. The bulk density was observed by the Archimedes law and the theoretical density was estimated to be $3.88g/cm^3$ and its hardness 14.7 MPa. From the dicing sawing test of $Al_2O_3$ specimen, behavior of surface roughness and band-saw wear are dominantly affected by the increase of the band-saw linear velocity. Additionally, an continuous pattern type of diamond band-saw was a very effective due to entry impact as a one-off for brittle material.

• Journal of Fashion Business
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• v.19 no.5
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• pp.1-16
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• 2015

The appearances and geometry structures of knitted fabrics have important effects on their functions as textile fabrics. Structural design of the woven fabric, prior to the manufacturing processes in the weaving mill, often leads to a similar predictable appearance in the final outcome with the corresponding weave design. The increase of the employment of elastic textile yarns in knitting fabrics for comfort stretch or outdoor sports wear knit products has, however, resulted in difficulties in predicting the final appearance of the knit structure design. Due to the stretchability and exceptional recovery behavior of the elastic yarns such as polyurethane elastomeric yarns, the appearance of the final product often differs from the initial knit design. At textile CAD program for preparing tricot knit designs has been employed in this study to predict the two dimensional appearance of the design. The similarities between the designs and corresponding knit products seem to be acceptable for the two-dimensional textile CAD program in this study. However, when elastomeric yarns are partially employed in the polyester filament tricot product, a considerable amount of departure from the design is apparent due to the constriction and/or deformation of property differences in the elastomeric yarns and polyester filament yarns. Therefore, another purpose of this study is to measure the departure of the final tricot product from the initial tricot design, especially in the case employing elastomeric yarns in the knit structure together with regular polyester filament yarns. For measuring the three-dimensional departure, a 3D scanning system has been used for the mesh reconstruction of the fabric specimen. Hopefully, the result from this study will be used as a guide to modify and improve the current textile CAD program proposed for the two-dimensional simulation of the tricot.

• Journal of the Korean institute of surface engineering
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• v.38 no.3
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• pp.106-111
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• 2005

Ternary Ti-B-C coatings were synthesized on WC-Co and Si wafers substrates by a PECVD technique using a gaseous mixture of $TiCl_4,\;BCl_3,\;CH_4,\;Ar,\;and\; H_2$. The effects of deposition variables such as substrate temperature, gas ratio, $R_x=[BCl_3/(CH_4+BCl_3)]$ on the microstructure and mechanical properties of Ti-B-C coatings were investigated. From our instrumental analyses, the synthesized Ti-B-C coatings was confirmed to be composites consisting of nanocrystallites TiC, quasi-amorphous TiB2, and amorphous carbon at low boron content, on the contrary, nanocrystallites $TiB_2$, quasi-amorphous TiC, and amorphous carbon at relatively high boron content. The microhardness of the Ti-B-C coatings increased from $\~23 GPa$ of TiC to $\~38 GPa$ of $Ti_{0.33}B_{0.55}C_{0.11}$ coatings with increasing the boron content. The $Ti_{0.33}B_{0.55}C_{0.11}$ coatings showed lower average friction coefficient of 0.45, in addition, it showed relatively better wear behavior compared to other binary coatings of $TiB_2$ and TiC. The microstruture and microhardness value of Ti-B-C coatings were largely depend on the deposition temperature.

• Journal of the Korean institute of surface engineering
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• v.38 no.3
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• pp.95-99
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• 2005

Quaternary Ti-Cr-Si-N coatings were synthesized onto steel substrates (SKD 11) using a hybrid method of arc ion plating (AIP) and sputtering techniques. For the Syntheses of Ti-Cr-Si-N coatings, the Ti-Cr-N coating process was performed substantially by a multi-cathodic AIP technique rising Cr and Ti targets, and Si was added by sputtering Si target during Ti-Cr-N deposition. In this work, comparative studies on microstructure and evaluation of mechanical properties between Ti-Cr-N and Ti-Cr-Si-N coatings were conducted. As the Si was incorporated into Ti-Cr-N coatings, the Ti-Cr-Si-N coatings showed largely increased hardness value of approximately 42 GPa than one of 28 GPa for Ti-Cr-N coatings. The average friction coefficient of Ti-Cr-N coatings largely decreased from 0.7 to 0.35 with increasing Si content up to 20 at. $\%$. In addition, wear behavior of Ti-Cr-N coatings against steel ball was much improved with Si addition due to the surface smoothening effect and tribe-chemical reaction.

• Nuclear Engineering and Technology
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• v.41 no.6
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• pp.821-830
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• 2009

In this paper, modal testing and finite element modeling results to identify the modal parameters of a nuclear fuel rod as well as its cladding tube are discussed. A vertically standing full-size cladding tube and a fuel rod with lead pellets were used in the modal testing. As excessive flow-induced vibration causes a failure in fuel rods, such as fretting wear, the vibration level of fuel rods should be low enough to prevent failure of these components. Because vibration amplitude can be estimated based on the modal parameters, the dynamic characteristics must be determined during the design process. Therefore, finite element models are developed based on the test results. The effect of a lumped mass attached to a cladding tube model was identified during the finite element model optimization process. Unlike a cladding tube model, the density of a fuel rod with pellets cannot be determined in a straightforward manner because pellets do not move in the same phase with the cladding tube motion. The density of a fuel rod with lead pellets was determined by comparing natural frequency ratio between the cladding tube and the rod. Thus, an improved fuel rod finite element model was developed based on the updated cladding tube model and an estimated fuel rod density considering the lead pellets. It is shown that the entire pellet mass does not contribute to the fuel rod dynamics; rather, they are only partially responsible for the fuel rod dynamic behavior.