• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.04a
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• pp.147-147
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• 2000

본 연구는 화장지용 펼프원료로 저급지인 색지(color ledger)고지를 사용함으로써 생산원 가를 절감하기 위한 목적으로 실시되었다. 일반적으로 색지 고지는 azo dyes, stilbene dyes, c copper phthalocyanine dyes와 같은 직접염료(direct dye)로 착색돼있는 것으로 보고되고있 다[) 한편, 펄프표백에 사용되는 약품은 hydrogen peroxide(HzOz), ozone(03), sodium h hypochloriten업oeD와 같은 산화표백제들과 F AS (formamidine sulfinic acid), sodium h hydrosulfite(NazSz04)와 같은 환원표백제들이 사용되는 것으로 널리 알려져 있다. 보통 화 장지용 펄프는 백색도가 78%이상이 되어야만 제품생산에 사용할 수 있는 것으로 인식되고 있다. 따라서 색지 고지를 이 목표로 달성하기 위한 탈색방법을 확립코자 다음과 같은 2가 지 실험을 실시하였다. 먼저, 색의 3원색인 빨강, 노랑, 파랑색의 색지 고지를 동일한 양으로 혼합하여 PY, HY, YH, YH, HY와 같은 5가지 방법의 실험을 실시하였다. 이중 YH 방법 이 가장 우수한 것으로 나타났다. 이 결과를 근거로 하여 여러 가지 색으로 구성된 색지 고 지가 50% 함유한 백상지 고지를 사용하여 Table과 같은 약품 및 조건으로 표백을 겸한 탈 묵실험을 실시하였다. 이 실험에서 백색도 81.8%, L* 93.3, a* -0.5, b* 4.1의 결과를 얻었다. 색지 고지의 탈색은 Y 단계에서 pH와 온도에 큰 영향을 받는 것으로 본 실험을 통하여 알 수가 있었다.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.533-540
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• 2022

This paper is the research result of designing and developing a BLDC motor for driving a condenser fan, which is widely used in air conditioners of commercial vehicles and specially equipped vehicles, and produced with a target value. The design of the motor was carried out in the order of designing the electric and magnetic circuits after determining the motor specifications. The process was repeated with different set values until the designed target condition was satisfied, and the electric and magnetic field distributions were made to be equal by reflecting the characteristics of the material. As a structural feature of the motor, it is a rotating field type composed of multipoles, and has a structure in which a permanent magnet is attached to the surface of the rotor. The manufactured BLDC motor is a 3-phase square wave driving method, with a rated voltage of 24 [V], a rotational speed of 2,500 [rpm], a rated current of 10 [A], and a power consumption of 180 [W]. A microcontroller for driving and controlling the motor was also manufactured.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.481-487
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• 2023

After conducting a hydrogen bomb test and launching an intercontinental ballistic missile (ICBM) in 2017, The Democratic People's Republic of Korea (North Korea, D.P.R.K.) declared the completion of its national nuclear capabilities. Currently, North Korea is refusing all nuclear inspections, but the possibility of nuclear inspections and the denuclearization process on the Korean Peninsula still exists. The Republic of Korea (South Korea, Rep. of Korea) has numerous reasons as a neighboring country to participate in North Korea's nuclear inspections and denuclearization, including technological capabilities, geographical proximity, and linguistic benefits. This study assumes nuclear inspections and verification within North Korea and aims to propose scenarios for the transportation and operation of personnel and equipment. The data and results compiled through this research are anticipated to serve as foundational information for future inspections and verifications on the Korean Peninsula. Furthermore, it is assessed that they could contribute to the development of strategies in preparation for participation in denuclearization efforts.

• Journal of the Korean Applied Science and Technology
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• v.40 no.2
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• pp.223-232
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• 2023

Oxidative stress plays a significant role in the pathogenesis of various skin conditions, resulting in cellular and tissue damage that can contribute to the development of skin tone unevenness, roughness and wrinkles. In this study, we found that Trifolium pratense L. extract (TE) attenuated oxidative-induced damage in HaCaT cells and elucidated the underlying molecular mechanism. Our finding demonstrated that TE effectively protected HaCaT cells against H₂O₂-induced cell death by inhibiting caspase-3 activation, downregulating Bax and upregulating Bcl-2, and attenuating the activation of three mitogen-activated protein kinases (MAPKs). Our results suggest that TE has remarkable cytoprotective properties against oxidative damage in HaCaT cells and could serve as a complementary or alternative approach to prevent and treat skin damage.

• Journal of Life Science
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• v.24 no.6
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• pp.595-602
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• 2014

Styela Clava tunic (SCT) has found some applications in many areas of medical treatment including as an anti-inflammatory compound, a wound healing film, in guided bone regeneration, and as a food additive. The protective effect of SCT aqueous extract (AE-SCT) on cell death induced by $H_2O_2$ treatment was investigated by measuring the changes in cell viability in HepG2 cells after AE-SCT treatment. High concentrations of antioxidant compounds including flavonoids (3.3 mg/g) and phenolics (32.3 mg/g) were detected in AE-SCT but no significant cytotoxicity was observed in HepG2 cells treated with AE-SCT. The viability of HepG2 cells was also not changed by treatment with different concentrations of AE-SCT after $H_2O_2$ treatment. However, cell viability was significantly increased in cells treated with three different concentrations of AE-SCT before $H_2O_2$ treatment. The greatest increase in cell viability was observed in the group treated with $50{\mu}g/ml$ AE-SCT, when compared with vehicle-treated group. FACS and DAPI staining analysis indicated that the decrease in number of dead cells was dependent on the concentration of AE-SCT. Alterations in the Bax/Bcl-2 ratio after $H_2O_2$ treatment were significantly restored by treatment with different concentrations of AE-SCT. These results indicate that AE-SCT, which contains high levels of antioxidants, may protect cells against death induced by $H_2O_2$ treatment.

• The Korea Journal of Herbology
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• v.26 no.2
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• pp.67-73
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• 2011

Objectives : The purpose of this research was total polyphenol contents, anti-oxidant activities, anti-inflammatory activities and anti-wrinkle activities of Ulleung islands plants for application as a cosmeceutical ingredients Methods : We were experimented total polyphenol contents, anti-oxidant activities, anti-inflammatory activity and anti-wrinkle activities. Results : In the physiological activities, most Ulleung islands plants is showed the highest anti-oxidant, anti-inflammatory activity in ABTS+ radical cation scavenging activity, hydrogen peroxide($H_2O_2$) scavenging activity, nitric oxide scavenging activity. All experiment of the water and ethanol extract from the Ulleung islands plants ingredients were gradually increased as well. Conclusions : These results suggest that extracts from Ulleung islands plants can be used in natural ingredient in food or cosmetic industry.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.12.2-12.2
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• 2011

Diamond-like carbon (DLC) coatings are used nowadays in various applications such as a protective coating against wear or corrosion in automotive parts, and recently its use is more and more apparent in particular biomedical applications [1]. The Japanese Ministry of Economy, Trade and Industry has started a program of collaborative study for industrial standardization of DLC films and their evaluation techniques. Japan New Diamond Forum (JNDF), Nanotec Corporation and the Nagaoka University of Technology are conducting this program. This project includes national organizations (businesses, universities, and research facilities), encompassing a wide range of requirements. JNDF organize Japanese project committee and working group. The purpose of this report is to discuss standardization and classification of DLC coatings.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.4
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• pp.346-351
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• 2003

Single-cell gel electrophoresis (comet assay) was used to detect DNA single strand break in blood cells from several marine fish species. Three fish species were collected from Georgia coastal area. Mummichog, Fundulus heteroclitus showed higher DNA damage than sea bass, Lateolabrax japonicus and trout, Oncorhynchus masou masou under the same experimental conditions. Mummichogs had more alkaline-labile sites on their DNA than other fish species. The comet assay with mummichog blood cells at pH 12.5 showed a dose-response curve with the increasing concentrations of hydrogen peroxide. While the isolated leucocytes showed no increase of DNA damage after in vitro exposure to 2-methyl-1,4-naphthoquinone (MNQ), erythrocytes showed dose-dependent DNA damage. These results indicate that the comet assay can be applied successfully as a bioassay using erythrocyte for environmental monitoring.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.519-523
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• 2007

Gas(or methane) hydrates are solid solutions when water molecules are linked through hydrogen bonding and create host lattice cavities that can enclose a large variety of guest gas molecules. The natural gas hydrate crystal may exist at low temperature above the normal freezing point of water and high pressure greater than about 30 bars. A lot of quantities of natural gas hydrates exists in the earth and many production schemes are being studied. In the present investigation, depressurization method was considered to predict the production of gas and the simulation of the two phase flow - gas and water - in porous media is being carried out. The simulation show about the fluid flow in porous media have a variety of applications in industry. Results provide the appearance of gas and water production, the pressure profile, the saturation of gas/ water/ hydrates profiles and the location of the pressure front.

• Corrosion Science and Technology
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• v.14 no.4
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• pp.195-199
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• 2015

Materials of choice for offshore structures and the marine industry have been increasingly favoring materials that offer high strength-to-weight ratios. One of the most promising families of light-weight materials is titanium alloys, but these do have two potential Achilles' heels: (i) the passive film may not form or may be unstable in low oxygen environments, leading to rapid corrosion; and (ii) titanium is a strong hydride former, making it vulnerable to hydrogen embrittlement (cracking) at high temperatures in low oxygen environments. Unfortunately, such environments exist at deep sea well-heads; temperatures can exceed $120^{\circ}C$, and oxygen levels can drop below 1 ppm. The present study demonstrates the results of investigations into the corrosion behavior of a range of titanium alloys, including newly developed alloys containing rare earth additions for refined microstructure and added strength, in artificial seawater over the temperature range of $25^{\circ}C$ to $200^{\circ}C$. Tests include potentiodynamic polarization, crevice corrosion, and U-bend stress corrosion cracking.