• Kyungpook Mathematical Journal
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• 제19권2호
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• pp.205-211
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• 1979

In this paper we continue the study of formation radical (F-radical) classes initiated in [3]. Hereditary and stronger properties of F-radical classes are discussed by giving construction for lower hereditary, lower stronger and lower strongly hereditary F-radical classes containing a given class M. It is shown that the Baer F-radical B is the lower strongly hereditary F-radical class containing the class of all nilpotent ideals and it is the upper radical class with $\{(I,\;N){\mid}N{\in}C,\;N\;is\;prime\}{\subset}SB$ where SB denotes the semisimple F-radical class of B and C is an arbitrary but fixed class of homomorphically closed near-rings. The existence of a largest F-radical class contained in a given class is examined using the concept of complementary F-radical introduced by Scott [5].

• 한국식품저장유통학회지
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• 제9권2호
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• pp.253-259
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• 2002

민들레 잎과 뿌리로부터 물추출물을 제조하여 항산화 활성 및 라디칼 소거활성을 분석하기 위하여 linoleic acid에 대한 과산화물 생성저해율, DPPH radical에 대한 소거활성, chemiluminescence를 이용한 hydroxyl radical에 대한 소거활성, EPR을 이용한 superoxide anion radical에 대한 소거활성및 hydrogen peroxide에 대한 소거활성을 측정하였다. 그 결과, 민들레 잎의 물추출물이 뿌리의 물추출물 보다 지방산에 대한 과산화물 생성 저해율이 높았고, DPPH radical, hydroxyl radical, superoxide anion radical 및 hydrogen peroxide에 대한 소거활성 역시 매우 높은 것으로 나타났다.

• Journal of Photoscience
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• 제8권1호
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• pp.33-37
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• 2001

Picosecond absorption spectroscopy has been employed in the study of the solvent dynamics of 1, 2, 4, 5-tetracyanobenzene/biphenyl derivative radical ion pairs, and the resulting rates of radical ion pair separation are faster in acetonitrile than in dichloromethane. In an effort to account quantitatively for such solvent effect on the rate of radical ion pair separation, an equation for the rate of radical ion pair separation is introduced, in which the rate depends exponentially on the electrostatic interaction energy in the radical ion pair. In our analysis of the types of electrostatic interaction energy based on the conducting spheres in dielectric continuum was chosen, and the rate equation employing this electrostatic energy provided information on the distance on the distance of radical ion pair separation and solvation energy of the radical ion pair, thereby providing quantitative explanation for the observed solvent effect on the rate of radical ion pair sepaaration.

• Preventive Nutrition and Food Science
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• 제11권1호
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• pp.10-16
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• 2006

Radical scavenging and antioxidant activities of Laminaria japonica and fermented its extracts were evaluated. Freeze-dried L. japonica was fermented by Aspergillus oryzae and extracted with distilled water. The extract solution was mixed with ethanol and centrifuged. The supernatant was ethanol soluble fraction, non-polysaccharide fraction (ESF), and residue was ethanol insoluble precipitation, polysaccharide fraction (EIP). ESF was subjected to sequential fractionation with dichloromethane, ethyl acetate, butanol and water. To determine the radical scavenging and antioxidant activities of these, DPPH radical, hydroxyl radical, superoxide anion radical scavenging activities and linoleic acid oxidation were tested. Among the extracts, ESF of fermented L. japonica showed the highest radical scavenging activity. The ESF showed DPPH radical scavenging activity of 64.33% at concentration of $50{\mu}g/mL$. It was higher than 57.70% of vit. C. Ethyl acetate and butanol fraction had high value of radical scavenging and antioxidant activities, especially butanol fraction of fermented L. japonica was 79.48 % of hydroxyl radical scavenging activity at concentration of $50{\mu}g/mL$. The fermented L japonica had radical scavenging and antioxidant activities higher than L. japonica. These results suggest that fermented L japonica is healthy food having radical scavenging and antioxidant activities.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.62-62
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• 2006

Based on the redox couples of a nitroxide radical, organic radical polymers were utilized as the electrode-active or charge-storage component for a secondary battery. We call a battery composed of the radical polymer electrode as "organic radical battery". Organic radical battery has several advantages: high capacity, high power-rate performance, long cycle ability, and environmentally-benign features. Synthesis and electrochemical studies of nitroxide polymers are described. Battery fabrication and cell performance are also reported.

• 대한수학교육학회지:수학교육학연구
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• 제12권2호
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• pp.193-212
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• 2002

What is radical constructivism There were many questions arose related with radical constructivism in mathematics education. In this paper, the author put seven frequentlyasked questions on radical constructivism and described each question one by one in light with constructivists' point of views. The questions included types of constructivista, radical constructivism, trivial or weak constructivism, and social constructivism; representative people in radical constructivism; matter of ontological reality; evaluation of others' work; shared meaning; social influence; and teacher's roles from the perspectives of radical constructivism. The author added his opinions ell each Question.

• KSBB Journal
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• 제32권2호
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• pp.140-145
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• 2017

The objective of this study was to compare antioxidant effects of different extracts of Salicornia bigelovii seed. DPPH radical scavenging activity, chelating activity of ferrous, superoxide anion radical-scavenging activity, hydroxyl radical scavenging activity, and contents of total polyphenol and flavonoid were measured for different extracts. Ethanol extract (10 mg/mL) was found to have the maximum DPPH radical scavenging and superoxide anion radical scavenging activities (65.26 and 62.36%, respectively). However, hot water extract (10 mg/mL) showed the highest hydroxyl radical scavenging and chelating activities (51.50 and 53.24%, respectively). Total phenolics and flavonoid contents in the ethanol extract were 522.8 and $480.35{\mu}g/mg$, respectively. They were 401.51 and $352.60{\mu}g/mg$, respectively, in the hot water extract. These results indicate that ethanol and hot water extracts of S. bigelovii seed have good potential to be used as a new source of antioxidants for functional foods, cosmetics, and pharmaceuticals.

• 생약학회지
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• 제32권3호통권126호
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• pp.253-256
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• 2001

The present study was designed for the improvement of routine measurement of superoxide and hydroxyl radical scavenging activities utilized by a microplate reader. Superoxide radical scavenging activity by the ascorbic acid, which is a well-known superoxide scavenger, was determined in a dose-dependent manner. Hydroxyl radical scavenging activity by the thiourea, which is a well-known hydroxyl radical scavenger, was also well detected in a dose-dependent manner. Our results suggest that the use of microplate reader to assay the superoxide and hydroxyl radical scavenging activities improves the accuracy of data and enables the use of much smaller amounts of samples and/or reagents, with much simpler experimental procedure. Therefore, These methods appear to be suitable for screening of superoxide and hydroxyl radical scavenging activities in both the plant medicinal extracts and the isolated compounds.

• 생명과학회지
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• 제30권11호
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• pp.956-964
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• 2020

액체크로마토그래피 (liquid chromatography; LC) 시스템과 연동된 radical 소거 활성 측정 시스템은 식물 추출물과 같이 수많은 성분으로 구성된 시료 중의 radical 소거 활성 성분을 확인하는 유용한 도구이다. 이와 같은 시스템을 사용하여 항산화 활성 성분을 가지고 있는 생약재로 알려진 유근피의 추출물을 대상으로 DPPH와 ABTS radical 소거 활성을 측정한 후 확인된 소거 활성 성분에 대한 질량분석을 실시하여 procyanidin B2, procyanidin B3, catechin-7-O-β-D-apiofuranoside, catechin-5-O-β-D-apiofuranoside로 각각 추정되는 4가지 성분을 확인하였다. 추출물 시료들 간의 상대적인 함량 비교를 위해 4가지 성분에 대한 MRM mode 분석 조건을 설정하여 LC-MS/MS를 활용한 유근피 추출물 중 radical 소거 활성 성분의 함량 비교 가능성을 검토하였다. 95% 에탄올 추출물을 기준으로 산출한 상대적인 함량 비교 결과에서 추출 용매의 에탄올 농도가 높아지면 radical 소거 활성 성분들의 함량이 높아지는 것으로 나타났으며, 각 추출물의 radical 소거 활성 측정 결과와 마찬가지로 에탄올 농도 50% 이상의 추출물들에서 procyanidin B3로 추정된 성분을 제외한 3가지 성분의 함량 차이가 크게 나타나지 않음을 확인할 수 있었다. 이와 같은 결과에 각 추출물의 수율을 추가로 감안하여 50% 수준의 에탄올 농도가 유근피의 radical 소거 활성 성분 추출에 더 효과적임을 알 수 있었다. 이와 같은 활성 측정 및 분석 방법을 활용하게 되면 유근피 자체의 품질관리뿐만이 아니라 추출물을 활용하는 다양한 제품 개발 단계에서 기존의 LC-UV 검출기 profile 비교보다 활용도가 높은 방법이 될 수 있을 것으로 판단된다.

• 정보보호학회논문지
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• 제31권6호
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• pp.1137-1148
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• 2021

CSIDH 기반 암호를 구현하는 데 있어서 가장 큰 단점은 Velu 공식을 활용하여 isogeny를 연산하기 위해 작은 소수 위수를 가지는 커널의 생성점을 선택하는 부분이다. 이 과정은 작은 위수의 경우 실패확률이 크기 때문에 연산량이 많이 들어서, 최근에 radical isogeny를 사용하는 부분에 관한 연구가 진행되었다. 본 논문에서는 CSIDH기반 암호 구현에 있어서 radical isogeny를 사용하는 최적 방안에 대해 제시한다. 본 논문에서는 Montgomery 곡선과 Tate 곡선 사이의 변환을 최적하였으며, 2-, 3-, 5-, 7-isogeny에 대한 공식을 최적화하였다. 본 논문의 결과, CSIDH-512의 경우 radical isogeny를 7차까지 사용할 경우 기존 constant-time CSIDH에 비해서 15.3% 빠른 결과를 얻을 수 있었다. CSIDH-4096의 경우 radical isogeny를 2차까지 사용하는 것이 최적이라는 결론을 얻을 수 있었다.