• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1443-1453
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• 2010

We simulated the roughing train of the rod mill of SEAH BESTEEL Inc. using finite element method to inhibit surface cracks initiation on workpiece. We designed 2nd pass (square roll) and applied to this roll in the roughing train of the rod mill. Also, we proposed new pass schedule, which changed roll gap of 3rd and 4th groove by using finite element method. We used shear damage model, which is dependent on shear stress ratio and compared the number of damaged elements on workpiece. A damaged element means surface crack. Consequently, after 2nd pass (square roll) is changed, the error rate decreased by 1.43% when compare to that of the old groove. And the number of damaged elements in the new pass schedule decreased by 37.6%, which is less than present pass schedule.

• Journal of the Korean Magnetics Society
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• v.8 no.5
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• pp.255-260
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• 1998

Fabrication condition and magnetic properties of ultrathin Co-based amorphous alloy have been investigated. When the ejection gas pressure was lower than 0.05 kgf/$\textrm{cm}^2$ at the roll speed of 55 m/s, ultrathin ribbons with the thickness less than 10 ${\mu}{\textrm}{m}$ were successfully obtained. The ribbon thickness decreased linearly with the decrease in ejection pressure. Moreover the significant decrease in ribbon width was accompanied with the decrease of thickness in the range of ejection pressure to form an ultrathin ribbon. This behavior was attributed to the decrease of effective ejection pressure in the both end-sides of rectangular nozzle due to the larger friction between molten metal and nozzle wall. The effective permeability at low frequency (1 kHz) decreased largely with the decrease in ribbon thickness, while the coercive force increased with the thickness decrease. It was considered that these behaviors were due to the enhancement of surface effect leading to the suppression of wall motion. However effective permeability at high frequency (1 MHz) increased with the decrease in ribbon thickness, and this was ascribed to the easier magnetization rotation owing to the reduction of eddy current.

• Journal of Sericultural and Entomological Science
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• v.34 no.1
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• pp.1-7
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• 1992

For a long-term preservation of silkworm stocks by frozen gonad storage, fundamental topics such as freezing rate and transplanting stage of the gonad, proper cryoprotectant, and super-cooling temperature and freezing point of the freezing medium were examined and following results were obtained. Proper method to anesthetize the ovary-recipient silkworm was to dip the animal to cold water for 10 minutes, and the ovary taken from the 4th instar larvae was more suitable for freezing-preservation than that from the 5th. Concerning the cryoprotectant, glycerol and DMSO were effective to prevent cryoinjury of the ovary, but sorbitol was not. The supercooling temperature and freezing point of the medium to freeze the ovary and testes were checked, and consulting with the results desirable cooling rate was confirmed. On the desirable conditions of transplanting methods, freezing rate and cryoprotectant concentration ect., the next generation was obtained when the females implanted frozen-thawed ovaries mated with normal males, but none of the normal females mated with the males implanted frozen-thawed testes laid fertilized eggs. Now it is needed to improve the connecting ration of the ducts associated with the transplanted testis to those of the hosts.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1429-1436
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• 2013

This study presents an approach for designing a vehicle rollover prevention controller using differential game theory and multi-level programming. The rollover prevention problem can be modeled as a non-cooperative zero-sum two-player differential game. A controller as an equilibrium solution of the differential game guarantees the worst-case performance against every possible steering input. To obtain an equilibrium solution to the differential game with a small amount of computational effort, a multi-level programming approach with a relaxation procedure is used. To cope with the loss of maneuverability caused by the active suspension, an electronic stability program (ESP) is adopted. Through simulations, the proposed method is shown to be effective in obtaining an equilibrium solution of the differential game.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.367-371
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• 2013

The half maximal inhibitory concentration ($IC_{50}$) values and trolox equivalent antioxidant capacity (TEAC) values were calculated by a 2,2'-diphenylpicrylhydrazyl (DPPH) assay and a 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid ($ABTS^{+{\cdot}}$) assay, in order to determine the antioxidative activities of the compounds. On the basis of the DPPH assay, quercetin had the strongest antioxidative potential of the flavonoids, followed in order by fisetin, 7,8-dihydroxyflavone, morin and kaempferol. Quercetin, fisetin and 7,8-dihydroxyflavone had higher antioxidant potentials than butyl hydroxyl anisole. Quercetin had the highest TEAC value amongst the flavonoids and isoflavonoids, followed in order by 3-hydroxyflavone, fisetin, 7,8-dihydroxyflavone and morin. Comparatively, isoflavonoids were found to have significantly weaker antioxidative potential than the flavonoids.

• Clean Technology
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• v.23 no.2
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• pp.133-139
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• 2017

Bio-based plastics containing the biomass content higher than 25 wt% have been considered as environment-friendly materials due to their effects on the reduction in the $CO_2$ emission and petroleum consumption as well as biodegradability after use. In this study, poly vinyl chloride, plant-derived plasticizers, by adding a biodegradable catalyst was observed a change in the biodegradability and physical properties. To produce the oxidative decomposition transparent bio film, which is broken down in the initial percent elongation and physical properties such as tensile strength, it was to test the safety of the product as a food packaging material. Poly vinyl chloride, primary plasticizer, secondary plasticizer, anti fogging agent, the combined stabilizer were mixed in a high speed mixer, then extruded using an extrusion molding machine, after cooling, winding, to produce a oxidative decomposition transparent bio film and the control film, with a thickness of $12{\mu}m$ through winder role. Mechanical properties tensile strength, elongation, and the maximum load elongation and biodegradation test. Transparent bio film produced by biodegradation catalyst is compared with the control film. Tensile strength and elongation of films were found to be no significant difference. Further, as a result of the biodegradation test for 45 days based on the ASTM D6954-04 method, biodegrability of film is 61.4%.

• Journal of Gastric Cancer
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• v.7 no.1
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• pp.9-15
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• 2007

Purpose: DNA methylation is an important epigenetic factor in tumorigenesis. We hypothesized that polymorphism of the promoter of the DNA methyltransferase 3b (DNMT3b) genes, which are responsible for regulating the methylation status of tumor suppressor genes, are associated with increased risk of gastric cancer. Materials and Methods: In this hospital-based case-control study, to determine the role of this polymorphism of the promoter of DNA methyltransferase 3b (DNMT3b) genes in gastric cancer, we genotyped 176 cases and 70 control subjects. To determine the genotype, we used a polymerase chain reaction restriction fragment length polymorphism assay. We compared alleles and genotypes between the two groups and revealed an association of DNMT3b promoter polymorphism with increased risk of gastric cancer in the Korean population. Results: Genotype frequencies were 14.8% (Cytosine-Cytosine), 71.6% (Cytosine-Thymine), and 13.6% (Thymine- Thymine) in the case patients and 40.0% (Cytosine-Cytosine), 42.9% (Cytosine-Thymine), and 17.1% (Thymine-Thymine) in the control subjects, respectively. Compared with CC homozygotes, CT heterozygotes had a 4.523-fold increased risk (OR, 2.13; 95% CI, 2.324~8.803), and the TT homozygotes had a 2.154-fold elevated risk (OR, 1.42; 95% CI, 0.899~85.165). For the T variant genotype (CT+TT), there was a 3.846-fold increased risk (OR, 1.88; 95% CI, 2.040~7.251). However, no significance was observed in the genotype distributions of both polymorphisms according to histopathology, stage of stomach cancer. The Ssame results were observed with Helicobacter infection. Conclusion: DNMT3b promoter polymorphism, especially the T variant genotype, is associated significantly with thean increased risk of gastric cancer.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.2
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• pp.111-118
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• 2016

Acne vulgaris is a chronic inflammatory condition characterized by comedo, papule, cyst, nodule and postinflammatory hyperpigmentation. Meanwhile, it is also induced by adverse event of drugs. Among them, acneiform folliculitis is a side effect of epidermal growth factor receptor (EGFR) inhibitor, which is an anticancer agent, and its incidence may occur in upward of 75 ~ 100% of cases. The main method of acne vulgaris treatment is oral antibiotics, retinoids, topical medication and so on. However, it is limitation that teratogenicity caused by retinoids and antibiotic resistance increased by using antibiotics. In this study, we aimed to evaluate the clinical efficacy and safety of topical recombinant human (rh) EGF in treating facial acne vulgaris. Twenty three Koreans (age: 10 ~ 29 years) with mild to moderate acne vulgar participated in the study and applied topical rhEGF cream (trouble control EGF) with 3 products (trouble control clarifying cleansing foam, trouble control all-clear filling toner, redroll calming moisture) on their face twice daily for four weeks. Several assessment methods were applied: Acne lesion counts score by investigator's global assessment, efficacy and satisfaction score by subjects. Skin sebum output level, hydration level and redness level were also measured at each visit. At the final visit, skin sebum level, transepidermal water loss, skin redness statistically decreased and acne lesions (comedone, papule) were statistically reduced. No severe side effects were observed during the study. In conclusion, topical rhEGF seems to be an effective and safe adjuvant treatment option for mild acne vulgaris.

• Journal of the Daesoon Academy of Sciences
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• v.35
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• pp.359-392
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• 2020

In this paper, we examined the development of Chinese Taoist architecture, its cultural implications, and comprehensively summarized the core principles of the Taoist ecological ideas that are reflected in Taoist architecture. This is a groundwork for exploring an ideological model for sustainable ecological architecture in modern cities. Taoist architecture has a long history that has led to changes, developments, and a gradual maturation. Zhi (治), Lu (廬), and Jing (靖), were the first architectural forms of the early Taoist body. These formed the basis for the future development of Taoist Courts (宮觀). The state-sponsored government-run Taoist Courts established from the time of the North and South Dynasties to the time of Tang Dynasty led to a constant standardization of the rites, and these Courts gradually became more and more formalized. Since the establishment of Quanzhenjiao (全眞敎) in the early 12th century, a movement that emphasized putiy training, architecture for the ascetic practice emerged in remote natural spaces suitable for strict ascetic practices. Meanwhile, in Taoist architecture, the type and structure of buildings were strengthened in order to worship various gods. The various Taoist Courts established through this historical process embody the elements, institutions, and ecological ideas of Taoist culture. Taoist architecture basically pursued the idealism of Paradise in a Deep Cave (洞天福地) and adopted a feng-shui theory of using natural terrain artfully in selecting a place and building a layout. This was reflected through their ecology. Meanwhile, Taoist architecture does not destroy the balance of nature by emphasizing the utilization of local natural resources whenever possible while selecting building materials according to the principles of yinyang and the five movements (陰陽五行). In addition, Taoism aims to select simple places for practising asceticism and ancestral rituals whenever possible because of the need to maintain a simple mind, suppress desire, and return to a state of purity. This attitude is an indication of a kind of simple ecological ideas and value of frugality easily found in Taoism. The ecological ideas of Taoism provide abundant resources for considering solutions to the ecological crisis that arises in the creation of residential environments. Through the ecological ideas of Taoism, we can find a direction to understand the relationship between human beings and nature while creating new, sustainable residential environments.