• Macromolecular Research
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• v.17 no.8
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• pp.616-622
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• 2009

In-depth understanding of the influence of hot pressing and melt processing on the properties of thermoplastic polyurethane (TPU) is critical for effective mechanical recycling of TPU scraps. Therefore, this study focused on the effects of hot pressing and melt mixing on molecular weight (MW), polydispersity index (PDI), melt index (MI), characteristic IR peaks, hardness, thermal degradation and mechanical properties of TPU. The original TPU pellet (o-TPU) showed two broad peaks at lower and higher MW regions. However, four TPU film samples, TPU-0 prepared only by hot pressing of o-TPU pellet and TPU-1, TPU-2 and TPU-3 obtained by hot pressing of melt mixed TPUs (where the numbers indicate the run number of melt mixing), exhibited only a single peak at higher MW region. The TPU-0 film sample had the highest $M_n$ and the lowest PDI and hardness. The TPU-1 film sample had the highest $M_w$ and tensile modulus. As the run number of melt mixing increased, the peak-intensity of hydrogen bonded C=O stretching increased, however, the free C=O peak intensity, tensile strength/elongation at break and average MW decreased. All the samples showed two stage degradations. The degradation temperatures of TPU-0 sample (359 $^{\circ}C$ and 394 $^{\circ}C$)were higher than those of o-TPU (342 $^{\circ}C$ and 391 $^{\circ}C$). While all the melt mixed samples degraded at almost the same temperature (365 $^{\circ}C$ and 381 $^{\circ}C$). The first round of hot pressing and melt mixing was found to be the critical condition which led to the significant changes of $M_n$/$M_w$/PDI, MI, mechanical property and thermal degradation of TPU.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.468-480
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• 2007

The urbanization is altering the hydrology, water quality, channel form of waterway and changing the composition of biological communities in the aquatic ecosystem. Recently, towns grew bigger by the drift of large numbers of people and the medium and small leather and dyeing industries around the Pocheon and Youngpyeong streams. The discharges of sewage were increased by them. The UII (urban intensity index) was 85 (st. P-3) and 91 (st. P-6) in the Pocheon stream and about 20 in the Youngpyeong stream. A total 141 taxa of epilithic diatoms which were composed of 2 order, 8 family, 30 genera. Dominant species were Navicula saprophila, N. subminuscula, Nitzschia palea, Gomphonema pseudoaugur in the Pocheon stream and Achnanthes alteragracillima, A. convergens, A. minutissima, N. minima, N. fonticola, N. frustulum and Cymbella minuta var. silesiaca in the Youngpyeong stream. It Showed the different composition of dominant species by the urbanization near two streams. In the relationships between UII and environmental factors such as EC, BOD, COD, TN, TP and DAIpo, UII showed the high relations $(r^2>0.8)$. It was the difference of organic pollution according to urbanization. It therefore, was higher the relative abundance and more the numbers of saprophilous taxa in the Pocheon stream than the Youngpyeong stream. The water quality of two streams by biological indicators(DAIpo) was polysaprobic state(st. P-3, P-4, P-5) in the Pocheon stream and was oligosaprobic (Y-1), mesosaprobic (Y-2, 3) and polysaprobic state (Y-4) in the Youngpyeong stream during the investigation periods.

• Journal of Adhesion and Interface
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• v.22 no.4
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• pp.118-127
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• 2021

In this study, the mechanical properties of vulcanized rubber were evaluated through compounding by controlling filler content to improve the mechanical properties of NBR rubber. Aramid and glass fibers with excellent heat resistance were used as fillers, and ceramics were additionally used in anticipation of a complementary effect, and as for the ceramic materials, needle-shaped and plate-shaped ceramics were used. Each filler was used in an amount of 5.0, 10.0, 15.0, and 20.0 phr in order to investigate the basic properties according to the amount of filler. To confirm the complementary effect through ceramic application, each 10.0 phr fiber and ceramic were mixed with 1:1 ratio to evaluate mechanical properties. As a result, it was confirmed that the decreasing ratio of tensile strength after heat aging was small in the order of aramid fiber, acicular ceramic, glass fiber, and plate ceramic in the case of applying the filler alone. In addition, the mechanical characteristics of vulcanized rubber using composite filler based on fibers and ceramics were evaluated, and it was confirmed that the composite filler had a complementary effect on thermal aging.

• Korean Journal of Heritage: History & Science
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• v.44 no.3
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• pp.150-163
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• 2011

In Ryeojidoseo(輿地圖書) Jinging(進貢) Bangmul(方物) item, The Goods name, date, How to make, quantity, etc. are recorded. However, the difference between the towns by the way it is written. at Goods in Jinging(進貢) Bangmul(方物) item, contained medicines, fish and shellfish, provisions, fruit, salted seaweed, weaponry, Leather, buchaeryu are included. And these goods are the town were offering some of the tribute(貢物) and the donation to the palace(進上物) in the mid 18th century. And this is closely related to daedongbeop(大同法). If this analysis approach to the provinces, This analysis makes clear. for example, in Gyeonggido(京畿道) only 12 species recorded and in Chungcheongdo(忠淸道) no a monthly-Jinsang(朔膳進上), in Chollado(全羅道) Sammyeongilbangmul(三名日方物) is not recorded but Bamboo and liabilities are recorded, no bangmul-Jinsang(方物進上) in Gangwondo(江原道), etc. This shows the nature of the Jinging(進貢) Bangmul(方物) item.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.3
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• pp.202-212
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• 2021

Objectives: The reproductive health of female workers has been extensively investigated in South Korea and other countries worldwide. However, few studies have discussed the reproductive health of male workers. In this study, we reviewed the recent literature that reports on the effects of occupational exposure on the reproductive health of male workers and the health of their children. Methods: In May 2020 we used the PubMed search engine to search the literature over the last 10 years and chose case-control, cohort, and cross-sectional studies and reviews. We selected epidemiological studies that investigated the association between pre-pregnant occupational exposure and the reproductive health of male workers and the health of their children. We excluded case reports, non-epidemiological studies (animal experiments, cellular-level experiments, and similar articles), and studies that described postnatal occupational exposure. Results: We eventually selected 23 studies. The studies that included exclusively male workers reported that those employed in the agricultural sector or those exposed to pesticides showed lower blood levels of reproductive hormones and a high risk of lympho-hematopoietic system cancer in their children. Male workers exposed to complex organic solvents and organic compounds showed a high risk of poor semen quality, increased time to pregnancy, decreased blood levels of reproductive hormones, and a high risk of lympho-hematopoietic system cancer in their children. Male workers employed in occupations that involved significant social contact, or in the leather and livestock industries, and in occupations with high levels of exposure to lead and organic solvents showed a high risk of malignancies, including lympho-hematopoietic system cancer, neuroblastoma, and central nervous system tumors in their children. Studies that investigated both male and female workers reported that children of male smelters showed a high risk of premature birth, and children of male workers exposed to metals showed a high risk of hypospadias and cryptorchidism. Children of male welders and workers employed in the glass, ceramic, and tile industries showed a high risk of premature birth. Conclusion: The findings of this study will serve as basic data for further research on male workers' reproductive health and provide a scientific basis for the development of strategies to protect the reproductive health of males employed in high-risk occupations. Moreover, the results of this study may provide guidelines to improve the understanding of and knowledge on male workers' reproductive health.

• Journal of Marine Life Science
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• v.7 no.1
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• pp.10-14
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• 2022

Monitoring infectious diseases for fishery species takes a key role in preventing disease emergence and spreading of cultured fishery species. This research has examined a total of 1,115 fishes of four species (leather carp, fancy carp, stone moroko, carassius auratus) at 23 farm in Jeollanamdo and Jeollabukdo in 2021 for pathogen infection. As a result of disease screening for three legally designated diseases (SVC, Spring viraemia of carp, EUS, Epizootic ulcerative syndrome, and KHVD, Koi herpesvirus disease), no infectious diseases were detected in all examined samples; cyprinid fish studied in Jeolla province would provide important information for declaring a disease-free nation or disease-free region.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.239-248
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• 2022

Forensic entomology is a study that purposes at field reconstruction through insects attracted to carcasses, and has been mainly studied using carcasses such as a pig and chicken. Therefore, this study was conducted to find out if there is a singularity by using the carcass of water deer with different conditions and shapes of the hair quality and to find out the appearance of a necrophagous insect. The water deer carcass was received from the Jeollanam-do Wildlife Rescue Management Center and research was conducted. From May 19 2021 to July 2 2021, the decay progress of the carcass was observed for about 6 weeks. A total of 51 species of 21 families in 4 orders of insects were collected. Even after the carcass completely decays, even at the stage where the activity of other insects is not observed, insects such as Dermestidae and Tenebrionidae are collected from the hairs and leather of water deer carcass until the last. It was confirmed that insects of the order Coleoptera other than Diptera can be used as forensic entomological data related to the decay of carcasses with fur.

• Journal of Korean Medicine Rehabilitation
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• v.33 no.2
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• pp.1-18
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• 2023

Objectives The purpose of this study was to evaluate the antioxidant, anti-inflammatory and wound healing effects of Samul-tang-ga-dansam water extract (SD) in wound-induced mice. Methods The mice were divided into five groups (n=7): the normal group, the control group, the positive control group, the low-dose SD group and the high-dose SD group. The normal group had no wounds and the other groups were wounded on the back with a leather punch. Distilled water was administered to the control group, 200 mg/kg of vitamin E was administered to the positive control group. In the low-dose SD group and the high-dose SD group, 1.23 g/kg and 2.47 g/kg of SD were administered, respectively. Antioxidant and anti-inflammatory protein levels were evaluated using western blot analysis. Skin tissue was analyzed by H&E, Masson's trichrome staining method. Results Oral administration of the SD significantly reduced the visible skin damage and decreased the reactive oxygen species and ONOO^- activity of the serum. It significantly increased heme oxygenase-1, superoxide dismutase, catalase, GPx-1/2, Nrf2 and Keap-1 which are antioxidant-related factors in skin tissue and reduced NF-κB p65, inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor α, interleukin (IL)-1β, IL-6 which are inflammation-related factors. Also, SD significantly decreased NOX2, p22^phox and p47^phox and increased α-smooth muscle actin and COL1A1 protein expression in fibroblasts involved in connective tissue repair. According to histological examination, the thickened epithelial layer was thinned and collagen fibers were increased to accelerate wound healing. Conclusions It is suggested that Samul-tang-ga-dansam has antioxidant and anti-inflammatory effects and promotes wound tissue repair.

• Journal of Korean Home Economics Education Association
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• v.34 no.4
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• pp.113-129
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• 2022

The purpose of this study is to propose implications by analyzing the textiles and clothing curriculum of vocational high schools. Literature and data were analyzed, surveys and FGI were conducted, and the following research results were derived. First, many schools chose 'Basic dress design' or 'Basic dress composition' as basic subjects. Through this, it was confirmed that technical training for practice is a priority for vocational schools, and that more discussion is needed regarding the lack of theoretical subjects. Second, similarly to the basic subjects, practical subjects offered are concentrated on 2 to 3 subjects. The teachers asserted that some subjects such as 'Knit apparel production' and the 'Leather and fur design production', which require a lot of equipment and advanced technology, cannot be offered without support from the government. Third, the NCS competency unit of the practical subjects is easy to proceed with the class or is closely concentrated on the type of manpower training presented by each department. Fourth, this study proposes that for technical education to expand students' choice, it is necessary to cultivate teachers competencies linked to the industry. The results of this study are expected to provide basic data on the organization of the next textiles and clothing professional curriculum and help understand vocational education at vocational high schools. In addition, it is believed that this study will contribute to developing and settling various subjects when the high school credit system is implemented by expanding students' choice of major-related subjects.

• Journal of Korea Entertainment Industry Association
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• v.13 no.3
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• pp.27-41
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• 2019

The study tested the old wines of Château Latour 1953 and tried to analyze the differences from the old wines. Even if not the great vintage, the quality change of old wine gives a new flavor, so it requires analysis results from empirical concepts, decanting, and testing. Based on the analysis results, the government wanted to re-evaluate the old wine and give consumers joy and implications for the wine. The wine to be studied is Château Latour 1953 and is an old wine from the French province of Pauillac. Wine blending is known to be 75% of cabernet sauvignon, 20% of melot, 4% of cabernet franc and 1% of petit verdot. The alcohol level is 13% and the test date is July 2-7, 2018(decanting period 5.4 days/15:00 p.m. on July 7). The testing site was a wine cafe in Daegu City, and the tester consisted of one FICB Korean grand commander and one KOV Finland commander and selected Japchae of Korean food as a mariage. The ullage of Chateau Latour 1953 was 3.0cm and was set up for one month for testing. Decanting time was applied to the calculation formula 2018(current year)-1953(vintage year)/12=5.4 days, which was investigated in this study. Aroma smelled of cork, old grapes, tobacco, leaves and leather, the bouquet was identified in five stages, and the testing was analyzed in seven stages.