• Journal of the Korea Fashion and Costume Design Association
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• v.11 no.1
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• pp.169-179
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• 2009

In order to preserve the Korean traditional gold foil, to develop as Korean traditional textile art by utilizing in modem fashion for textile industry, and to examine utility of the material which can be used in the modem wearing, interior goods and fashion terms, Textiles Applied Korean Traditional Gold Foil were developed. The results are as follows: First, important factors of the gold foil image should be extracted as materials quality, color and pattern, and modem and practical qualities should be proceeded when developing the image of the gold foil into modem quality material. Second, since gloss of fabric developed by a traditional method is somewhat strong, uniformity being a little bit low for hand-made manufacturing, and practical quality is low for high cost, deletion of the gold foil, etc. So it hasn't been appropriate for studying modem fashion material. Third, Jacquard weave has been examined as the most appropriate method in order to present the gold foil image among a number of textile manufacturing techniques Fourth, considering factors deciding the image of the gold foil and a sense of beauty of modem society, gloss of the foil has been lessened by expressing pattern to lower traditional quality and primary color. Fifth, pattern motives of developed materials have been extracted tram traditional gold foil patterns, and materials have been chosen considering of concepts and motives, and dragon pattern, crane pattern and bat pattern, Sixth, wearing, pin-up works, bed linen, fabrics for chairs, ties, bags, shoes, umbrellas, etc. are produced with the developed materials, and practical use and modern quality have been examined. The result is very satisfactory.

• Tribology and Lubricants
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• v.33 no.1
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• pp.15-22
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• 2017

Because the running speed of vehicles is increasing and a shorter braking distance is required, high heat-resistant brake pads are needed to satisfy the requirements of customers and car makers. In the near future, hazardous materials such as Cu, Cr, Zn, and Sb will be restricted from use in friction materials. Ceramic composites reinforced by carbon fibers are good candidates for eco-friendly friction materials. In this study, we develop ceramic composite friction materials. The friction materials are composed of carbon fibers, Si, SiC, graphite, and phenol resin and are prepared by hot forming and heat treatment at high temperatures. The density, void ratio, and compressive strength are $1.59-1.66g/cm^3$, 16.6-20, and 70-90 MPa, respectively. Friction and wear tests are performed using a pin-on-plate-type reciprocating friction tester at 25, 100, and $200^{\circ}C$. The counterpart material is a CrMoV steel extracted from a KTX brake disc. Friction coefficient, wear amount, and wear mechanism are measured and examined. We determine that the friction coefficients depend on the temperature and the fluctuation of the friction coefficients is larger at higher temperatures. The amount of wear increases with the surface temperatures of the specimens. The tribological properties of the developed composites are similar to those of a Cu-based sintered friction material. Through this study, it is confirmed that ceramic composite materials can be used as friction materials.

• Tribology and Lubricants
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• v.33 no.5
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• pp.220-227
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• 2017

In this work, carbon nanotube and nano-size alumina particle are exploited as additive for lubrication experiment. We used pin-on-disk type tribometer to investigate the tribological characteristics of lubricants with respect to additives and rotational speed. We conducted more than 15 trials of tribotests for two hours for each specimen to obtain stable and accurate frictional force and to create measurable wear track on the substrate. We conducted tests at the boundary/mixed lubrication regime to evaluate the influence of additives on the tribological characteristics. We found that the friction coefficient decreased as the rotational speed increased and as additives were added. In particular, the reduction of friction by adding additives was more significant at low rotational speed than at high rotational speed. We speculate that the additives helped to separate and protect the two contacting surfaces at low speed, while the influence of additives was not significant at high speed since sufficiently thick lubricant film was formed. The wear of the substrate was also reduced by adding additives to the lubricant. However, in contrast to friction, the amount of wear at high rotational speed was less when alumina particles were added to the lubricant than the amount of wear at low speed. We speculate that the increased wear at low rotational speed is as a result of the intermittent abrasive wear caused by alumina particles with uneven shape, while the reduced wear at high speed is as a result of sufficient film thickness which prevented the abrasive wear.

• Journal of Biosystems Engineering
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• v.37 no.2
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• pp.122-129
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• 2012

Purpose: Recent mechatronics technology is the most appropriate high technology in agricultural applications to save repetitious labor. Method: Cow's body parameters were measured by several traditional measurers. Image processing technology was used to measure automatically their parameters to reduce labor and time. The parameters were measured form a small model cow which is easily measured, instead to a real cow. The image processing system designed and built for this project was composed of a PC, grabber card, and two cameras, which are located on the side and the top of the model cow. Tests of verification had measured 10 dairy cows. Result: Nine parameters of the model cow's body were measured, and the difference between the real data and the data by image processing was less than 16.7%. Based on the results of the research, the parameters of a real cow had measured of chest depth, withers height, Pelvic arch height, body length, slope body length, chest width, hip width, thurl width, and pin bone width were compared with image processing data. Conclusions: In the Demonstration test, Result had obtained similar data of cow model experiments, and the most of errors were shown less than 5% relatively good result.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.278-290
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• 1997

The purposes of this study were to evaluate and compare the pulpal anesthesia induced by an inferior alveolar nerve block and that by Gow-Gates technique, and to investigate the relationship between pulpal anesthesia and intraoral soft tissue responses. After one side of mandibule was anesthetized with inferior alveolar nerve block or Gow-Gates technique using 2 % lidocaine with 1 : 100,000 epinephrine in 19 volunteers of ages between 24 and 29 (16 males and 3 females, average age 25.9 yrs.), electric pulp tests were done on the canine teeth of the anesthetized side and contralateral one before, at 1 min, continued at every 5 minutes until 60 min, and every 10 minutes until 100 min after completion of local anesthetic injection. Degree of pulpal anesthesia was classified as anesthetic failure, possible anesthesia and complete anesthesia by the criteria based on the thresholds to electric pulp test of contralateral canine and the currents of the electric pulp tester. Subjective signs on the lower lip and tongue were checked and prick-pin tests were done on the buccal gingiva of the first molar, buccal and lingual gingiva of the canine tooth at 5, 10 and 20 min after the completion of anesthetic injection. Thresholds to electric pulp test, degree of pulpal anesthesia and relationship between the pulpal anesthesia and soft tissue responses were analyzed with SPSS, paired t-test, Wilcoxon matched-pairs signed-ranks test and correlation analysis. The results were as follows : No significant differences were found in the peak thresholds to electric pulp test, in the induction time to it and in the depth of pulpal anesthesia between inferior alveolar nerve block and Gow-Gates technique (p>0.05). There was no significant relationship between pulpal anesthesia and soft tissue responses in both inferior nerve block and Gow-Gates technique.

• Textile Coloration and Finishing
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• v.18 no.6 s.91
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• pp.16-24
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• 2006

The purpose of this study is to improve the defects of chitosan crosslinked viscose rayon by ECH and to describe the change of hand of chitosan crosslinked viscose rayon fabrics. The chitosan crosslinked viscose rayon were manufactured by crosslinking process using ECH as crosslinking agent, 2 wt% aqueous acetic acid as a solvent of chitosan and ECH, and 20 wt% aqueous sodium hydroxide as crosslinking catalyst. Viscose rayon were first immersed in the pad bath of the mixed solution of chitosan and ECH, padded up to 100 wt% wet pick-up on weight of fiber(owf), precured on pin frames at $130^{\circ}C$ for 2 minutes, immersed in NaOH solution and finally wash and dry. Antimicrobial properties of the viscose rayon treated with chitosan were measured by the shake flask C.T.M. 0923 test method with staphylococcus aureus(ATCC 6538) as the microorganism. When the concentration of chitosan was increased chitosan crosslinked viscose rayon's LT, WT, B, 2HB and MIU were increased and G, 2HG, SMD, T and $T_m$ were decreased. On the other hand, WT, EM were decreased and RT was increased at $1{\times}10^{-2}M$ ECH. The optimum condition for crosslinking was that ECH concentration was between $1{\times}10^{-2}M\;and\;5{\times}10^{-2}M$. Antimicrobial effects of rayon fabric treated with chitosan was excellent.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.509-514
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• 2007

In this study, we optimized the production of ${\gamma}-polyglutamic$ acid (PGA) in soybean milk cakes (SMC) fermented with Bacillus subtilis GT-D and B. subtilis KU-A, to be utilized as a functional food ingredient. PGA production was dependent upon the glutamate content, fermentation time, and type of Bacillus sp. The consistencies of the SMCs fermented by B. subtilis GT-D and B. subtilis KU-A were highest after 36 hr of fermentation, and then decreased gradually. The SMC fermented by B. subtilis KU-A had a higher consistency than the SMC fermented by B. subtilis GT-D. In the presence of 10% defatted soy flour (DFS), 5% glutamate in the SMC was efficiently converted into polyglutamic acid (PGA) for 24 hr, indicating a conversion yield above 96%, but its conversion then decreased with higher concentrations of glutamate. The soluble solid content (mucilage) of the SMC fermented with B. subtilis KU-A was 9.5%(w/w), and composed of 65.6% PGA (Mw 1,536 kDa) and some polysaccharides. However, the SMC fermented with B. subtilis GT-D had a mucilage content of 7.8%(w/w), and was composed of 66.4% PGA (Mw 1,409 kDa), 11.5% levan, and some polysaccharides. The viscoelastic values of the mucilage obtained using B. subtilis KU-A were much higher than those of mucilage obtained using B. subtilis GT-D. Also, the G'-value (elastic modulus) was higher than the G"-value (viscous modulus).

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.432-437
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• 2011

The quality characteristics and effects on the proliferation of human hepatoma HepG2 cells due to dropwort (Oenanthe javanica) extracts naturally fermented with fructooligosaccharides were investigated. Dropwort was fermented by steeping with the same weight of oligosaccaride at room temperature for 1 year, and then stored at 4$^{\circ}C$ for 1 or 2 more years. During the fermentation periods, total flavonoid content, Hunter's color (a value), and viable cell counts decreased, but reducing sugars including glucose and fructose increased. HepG2 cell proliferation was inhibited significantly by the three extracts, but no effects were observed on Chang cells. In particular, the dropwort extract fermented for 1 year showed the highest inhibitory effect. These results demonstrate that the quality characteristics and anti-proliferative effects of dropwort were affected by fermentation period. It is concluded that dropwort extract fermented for 1 year showed the highest functional properties and quality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.6
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• pp.798-804
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• 2008

The physicochemical properties of carrot beverage fermented by Leuconstoc mesenteroides SM isolated from carrot juice were dependent upon the sucrose concentration and beet extract content. The addition of beet extract increased the consistency index and bioconversion of sucrose in the carrot juice fortified with Phellinus linteus extract, showing the highest consistency value at 2% beet extract. The polyphenol content and antioxidant effect of fermented carrot beverage were increased as the content of beet extract increased. Particularly, the consistency of fermented carrot beverage was greatly increased by the cold storage for 120 hr. After the cold storage for 2 weeks, fermented carrot beverage fortified beet extract showed the red-purple color with higher color value (a) and the viable cell counts of $10^9$ CFU/mL.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1277-1279
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• 1994

In the structure of ZnO/nip-SiC: H/metal substrate amorphous silicon (a-Si:H) solar cells, the effects of inserting a rear textured ZnO in the p-SiC:H/metal interface and a graded bandgap buffer layer in the i/p-SiC:H have been analysed by computer simulation. The incident light was taken to have an intensity of $100mW/cm^2$(AM-1). The thickness of the a-Si:H n, ${\delta}$-doped a-SiC:H p, and buffer layers was assumed to be $200{\AA},\;66{\AA}$, and $80{\AA}$, respectively. The scattering coefficients of the front and back ZnO were taken to be 0.2 and 0.7, respectively. Inserting the rear buffer layer significantly increases the open circuit voltage($V_{oc}$) due to reduction of the i/p interface recombination rate. The use of textured ZnO markedly improves collection efficiency in the long wavelengths( above ${\sim}550nm$ ) by back scattering and light confinement effects, resulting in dramatic enhancement of the short circuit current density($J_{sc}$). By using the rear buffer and textured ZnO, the i-layer thickness of the ceil for obtaining the maximum efficiency becomes thinner(${\sim}2500{\AA}$). From these results, it is concluded that the use of textured ZnO and buffer layer at the backside of the ceil is very effective for enhancing the conversion efficiency and reducing the degradation of a-Si:H pin-type solar cells.