• Polymer(Korea)
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• v.31 no.4
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• pp.322-328
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• 2007

Mono-dispersed polyamide 6(Nylon 6) micro-particles sized in $4{\sim}5\;{\mu}m$ diameter were prepared by dispersion polymerization of ${\varepsilon}-caprolactam$ in liquid paraffin as a dispersion medium. Potassium metal(K) as a catalyst was separately added twice over the anionic ring-opening polymerization of ${\varepsilon}-caprolactam$. The size, shape, and size-distribution of prepared particles were varied with the concentration of anti-coagulant as well as the amount of initiator and catalyst. As the initiator concentration was in the range of $0.97{\sim}1.17\;wt%$ in monomer, about 90.6% of yield was accomplished. In addition, the highest yield of well-spherically shaped micro-particles was achieved by adding about $1.3{\sim}1.4\;wt%$ of catalyst.

• Polymer(Korea)
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• v.38 no.3
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• pp.314-319
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• 2014

Three kinds of thermal stabilizers for nylon 4 were synthesized to incorporate both hindered amine groups and methylene units with various lengths. It is expected that the hindered amine groups play a role in the capture of degradation-triggering species. Considering sequence rules, hydrogen bonding formed between nylon 4 and the stabilizers is optimized to alter the lengths of the methylene units in the stabilizers. As a result, it was found that a tetramethylene unit in the stabilizer is an optimal length for hydrogen bonding in terms of isothermal thermogravimetric analysis (TGA). Considering the slight and often negligible improvement of thermal stability of nylon 4 containing commercially-available nylon 6 stabilizers, retardation of thermal degradation has been substantially improved upon.

• Korean journal of applied entomology
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• v.43 no.4 s.137
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• pp.275-279
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• 2004

This study compared the biological characteristics, nymphal development, adult longevity, and oviposition of the bean bug, Riptortus clavatus Thunberg, in fibrous nylon and glass-tube in the insectary at $28{\pm}2^{\circ}C$ and 16L:8D of photoperiod. Nymphal duration in the fibrous nylon-tube was 1 day longer than in the glass tube; the difference was attributed to the developmental duration of the fifth instar. Percent emergence in the fibrous nylon-tube was $64\%,\;8\%$ higher than in the glass tube ($56\%$). In the fibrous nylon-tube, adult longevities for female and male were 4.1 times and 6.0 times higher than those in the glass tube. Preoviposition period was 1 day longer in the fibrous nylon-tube than that in the glass tube. The total number of eggs laid was 3.5 times more in the fibrous nylon-tube than in the glass tube. The oviposition duration lasted about 30 days for the bean bug in the fibrous nylon-tube and about 8 days for those in the glass. Accordingly, the fibrous nylon-tube was found more conducive than the glass tube for determining the biology of bean bug.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.10
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• pp.867-875
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• 2018

Conventional nylon wire cutting-type holding and release mechanisms (HRMs) are limited to securely hold the solar panel under launch environment as the size of the panel increases because the nylon wire is tightened directly on the surface of the solar panel. In this study, we proposed a nylon wire cutting-type HRM for 6U CubeSat's solar panel applying elliptic-shaped bracket with a Ball & Socket interface. The proposed HRM has the advantage of higher holding capability along in-plane and out-of plane directions of solar panel and simplicity in tightening process of nylon wire. The design drivers of structural design of CubeSat's solar panel with the proposed HRM were defined by structural analysis under launch loads. In addition, The design effectiveness of the proposed HRM was verified through the functional tests according to the thickness of nylon wire and the number of wire winding under various temperature conditions.

• Textile Coloration and Finishing
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• v.16 no.6
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• pp.35-43
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• 2004

This study surveys the physical properties of ATY produced with FDY and POY. ATY is made with 70d Nylon FDY and 80d Nylon POY using AIKI air jet texturing machines, respectively. The processing parameters such as air pressure and yam speed are varied, and air pressure is varied ranging with 8.5bar, l0.5bar and 1l.5bar, and yarn speed is varied ranging with 400m/mim, 450m/mim, and 500m/min. The various physical properties of ATY made by POY and FDY denier, wet shrinkage, dry shrinkage, tensile properties, thermal stress and instability are measured and discussed with air pressure and yam speed. The shrinkage simulation of ATY is performed for analysing the process shrinkage on the dyeing and finishing processes.

• Journal of Fashion Business
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• v.7 no.3
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• pp.36-44
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• 2003

Chitosan treatment of textile fabrics has been studied to improve fabric characteristics and functions. Natural dyestuffs have been more actively employed in environment-conscious finishing products. In this study, chitosan treated cotton and nylon fabrics were prepared for dyeing with a few natural dyestuffs. These were Caesalpina sappan, Gardenia jasminoides, and cochineal in the form of powder. Hand-related physical and mechanical properties and luster characteristics were examined using the KES-FB series instruments and a set of luster measuring equipment. The chitosan treatment seemed to be more effective in terms of increasing stiffness for cotton fabric. Since cotton fibers have more -OH groups in the molecules, they provide more linkage sites with the chitosan than the nylon 6 fibers do.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.3
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• pp.500-514
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• 1996

The purpose of this study was to observe the tissue response in applying staples and various suture materials to both scalp and buccal mucosa in rabbits. 18 rabbits were divided into 6 groups. The incised wounds of both scalp and buccal mucosa were sutured with staples, polyglactin 910, chromic catgut, mer silk and nylon. The experimental animals were sacrificed after 1, 3, 5, 7, 10, 14 days posto peratively 3 animals at one time. The tissue was stained with Hematoxylin and eosin, and Masson's Trichrom. In light microscopic examinations, the sutured sites were examined histologi cally according to 6 degrees about inflammation and collagen deposit. The results were obtained as follows, 1. The chromic catgut, an absorbable suture material, was absorbed by 7 days, whereas polyglactin 910 and mersilk began to get absorbed after 7 days. 2. Mersilk manifested a broad range of inflammation in the scalp, and both staple and nylon showed a severe inflammatory reaction in the buccal mucosa. 3. With polyglactin 910, both tissue samples showed only minor foreign body reaction, however in the scalp, the process of fibrosis took place compara tively slowly, whereas in the buccal mucosa, it occurred promptly and manifested active fibrosis by 7 days. 4. Mersilk showed widespread a matrix formation in both scalp and buccal mucosa, and showed the most severe inflammatory reaction by 3 days, which did not seem to decrease even after 7 days. 5. Both staple and nylon showed relatively a severe inflammatory reaction, however fibrosis took place rather promptly compared to the other groups. 6. Generally, in the buccal mucosa fibrosis occurred more promptly than in the scalp in both control and experimental groups. 7. Retention of the suture material and stability of the knot were the best with the staple, and better stability was manifested by the multi-stranded poly glactin 910 and mersilk than singlestranded chromic catgut and nylon. From above results, in the buccal mucosa absorbable suture materials especially polyglactin 910 showed better response in the aspect of inflammatory reaction, while in the scalp monofilament suture materials such as staple and nylon manifested a early fibrosis and collagen formation.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2354-2358
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• 2007

MALDI-TOF-MS technique was applied to obtain structural and compositional information of synthetic polyamides, Nylon6 and Nylon66. Mass spectra of both the original and the hydrolyzed polyamide samples were analyzed using the self calibration method as well as the internal calibration method with the standard materials of known masses. The MALDI-TOF mass spectra of Nylon6 samples showed the presence of protonated, sodiated, and potassiated ions that were assigned to cyclic and NH2/COOH terminated linear oligomers. From the MALDI-TOF mass spectra of Nylon66 samples, the potassiated linear oligomers with three different end groups are identified as well as the cyclic oligomers, i.e., NH2/COOH terminated oligomers, NH2/NH2 terminated oligomers, and COOH/COOH terminated oligomers. Full characterization of the molecular species and end groups present in the polyamide samples has been achieved, and also the changes in mass spectral patterns after the hydrolysis of the samples are presented.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2359-2362
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• 2007

MALDI-TOF-MS technique was applied to obtain structural and compositional information of synthetic polyamides, Nylon6 and Nylon66. Mass spectra of both the original and the hydrolyzed polyamide samples were analyzed using the self calibration method as well as the internal calibration method with the standard materials of known masses. The MALDI-TOF mass spectra of Nylon6 samples showed the presence of protonated, sodiated, and potassiated ions that were assigned to cyclic and NH2/COOH terminated linear oligomers. From the MALDI-TOF mass spectra of Nylon66 samples, the potassiated linear oligomers with three different end groups are identified as well as the cyclic oligomers, i.e., NH2/COOH terminated oligomers, NH2/NH2 terminated oligomers, and COOH/COOH terminated oligomers. Full characterization of the molecular species and end groups present in the polyamide samples has been achieved, and also the changes in mass spectral patterns after the hydrolysis of the samples are presented.

• Journal of the Korean Society of Costume
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• v.54 no.6
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• pp.141-148
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• 2004

This study examines the dyeability of fabrics in relation to dyeing temperature, time, concentration, and the number of repeated dyeings. For this study, at first we extracted natural dyes from the peel of C.umshiu mandarin, which is fast as a dye and considered as recycling agricultural wastes. Additionally, it represents the image of Jeju Island. Then, we dyed cotton, wool, silk and nylon fabrics with the extracted dyes. The findings of this study are as follows. 1) Dyed cotton, wool, silk and nylon fabrics with the extract of C.umshiu mandarin peel are generally yellow. 2) Wool, nylon, silk, and cotton, in this order, are of good dyeability; Wool fabrics have the highest dyeability and cotton fabrics have the lowest. The dyeabilty of cotton fabrics was not improved even after dyeing in different conditions. 3) Colorfastness with washing, rubbing and perspiration are all good, while colorfastness with light is poor. 4) Higher dyeing concentration makes better dyeability. 5) Dyeability is enhanced as the dyeing temperature increases, while the dyeability of silk and nylon is relatively good even at low temperatures. 6) Looking at dyeability according to dyeing time, the longer the dyeing time, the better the dyeablility. Sixty minutes of dyeing time is appropriate to dye fabrics. 7) With an increase in the number of repeated dyeings, increased dyeability is obtaihed.