• Bulletin of the Korean Mathematical Society
• /
• v.50 no.1
• /
• pp.125-134
• /
• 2013

An element in a ring R is strongly clean provided that it is the sum of an idempotent and a unit that commutate. In this note, several necessary and sufficient conditions under which a $2{\times}2$ matrix over an integral domain is strongly clean are given. These show that strong cleanness over integral domains can be characterized by quadratic and Diophantine equations.

• Communications of the Korean Mathematical Society
• /
• v.34 no.4
• /
• pp.1069-1078
• /
• 2019

Let R be a ring with identity and P(R) denote the prime radical of R. An element r of a ring R is called strongly P-clean, if there exists an idempotent e such that $r-e=p{\in}P$(R) with ep = pe. In this paper, we determine necessary and sufficient conditions for an element of a trivial Morita context to be strongly P-clean.

• The Research Journal of the Costume Culture
• /
• v.12 no.5
• /
• pp.819-831
• /
• 2004

Under the social conditions that an understanding of a men change socially and men's interests in their appearances are on the increase, this research intends to study and analyze the changes of people's sensibility of values on ads for men's cosmetics, which is said to be performed the social, cultural function reflecting the social consciousness, the value and the idea creating a new one. The documents for the research was sindonga. The ad showed that they've changed making a difference according to the times. In 1970s, it expressed a man for cleanness and modernity living in urbanized and modernized society. On the other hand, it expressed a man who won success socially and enjoyed a comfortable life in a dignified manner, or a man who was fond of sports leisure activity pursuing a clam and composed life and was interested in the skin and an appearance in 1980s. From 1990 to 2002, it expressed a man of challengeable manly beauty having a strong will toward social achievement, or a man who has a sweet manly beauty with sex appeal to a woman. Besides, it expressed a man who is soft, faithful and affectionate with a liberal and peaceful atmosphere as well.

• Transactions on Electrical and Electronic Materials
• /
• v.18 no.3
• /
• pp.148-150
• /
• 2017

For the improvement of the anti-fouling features of porcelain electrical insulators, in this study, the surface of an insulator was coated with a functional material to expand the insulator's self-cleanness. The anti-fouling and mechanical features of the functional film coating of ceramic substrates made from components like an electrical insulator were analyzed. The coating methods that were used were spray coating, dip coating, and fabric coating. Following the coating, the contact angle of the coated surface was measured, revealing that the spray coating method offered the lowest angle ($13.7^{\circ}$) and a strong hydrophilic feature. The anti-fouling analysis showed that the anti-fouling features improved as the contact angle decreased. The mechanical properties - hardness and adhesion - were both excellent at 9H and 5B, respectively, regardless of the coating method that was used.

• The Korean Journal of Food And Nutrition
• /
• v.18 no.4
• /
• pp.385-394
• /
• 2005

The objective of this study is to stimulate the satisfaction on food color sensitivity through objectifying the color sensitivities on customer's foods. The preference analysis on food sensitivity adjectives is measured on 5-point scale by preferring degree on each adjectives. And it is calculated on the sensitivities for the SD method that is used for finding whether it is strong or not on food image stimulus which was photographed on the 8 restaurants in Seoul. We found the outcome as follows. The most preferred sensitivity adjective is 'cleanness', and the worst preferred one is 'unshapliness'. It is differed on genders by $95\%$ confidence interval. The attractiveness, simplicity, richness, comfort and elegance are derived from the result of factor analysis for food color sensitivity. The yellow or orange color foods are main one for the simplicity and comfort. The orange color food are fit on richness and elegance factor, and it will be most effective if choosing the color more similar to brown one.

• The Journal of the Korea Contents Association
• /
• v.18 no.1
• /
• pp.19-30
• /
• 2018

The main purposes of this study are to analyze the contents and text network of online tourism information. For this purpose, Jeju Island, one of the representative tourist destinations in South Korea is selected as a study site. And this study collects the contents of both JeJu official tourism website and Sina Weibo's personal blogs which is one of the most popular Social Network Systems in China. In addition, this study analyzes this online text information using ROST Content Mining System, one of the Chinese big data mining systems. The results of the content analysis show that the formal website of Jeju includes the nouns related to natural, geographical and physical resources, verbs related to existence of resources, and adjectives related to the beauty, cleanness and convenience of resources mainly. Meanwhile, personal blogs include the nouns of Korean-wave, food, local products, other destinations and shopping, verbs related to activity and feeling in Jeju, and adjectives related to their experiences and feeling mainly. Finally, the results of text network show that there are some strong centrality and network of online tourism information at formal website, but there are weak relationships in personal blogs. The results of this study may be able to contribute to the development of demand-based marketing strategies of tourists destination.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.31 no.1 s.49
• /
• pp.17-23
• /
• 2005

We had previously reported that Selina (selina-4(14), 7(11)-dien-8-one) was isolated from methanol extract of Afractylodes rhizome and has strong whitening activity in B16 melanoma cells. In this report, we demonstrated its action mechanism in melan-a cells, non-tumorigenic melanocytes. We also investigated the clinical efficacy of cosmetic preparation containing Selina. Selina reduced the melanin synthesis of Melan-a cells by $50\%$ at a concentration of $10 {\mu}g/mL$ without any apparent cytotoxicity. We also found that the treatment of cells with Selina decreased tyrosinase activity by $60\%$ at a concentration of $10 {\mu}g/mL$ but Selina was not a direct inhibitor of tyrosinase activities. To elucidate the action mechanism of Selina, we investigated the changes in mRNA and protein level of tyrosinase, TRP-1 and TRP-2 using RT-PCR and western blotting, respectively. As a result, the mRNA and protein level of tyrosinase were markedly reduced at $10 {\mu}g/mL$ of Selina without any effect on TRP-1 and TRP-2. These results suggest that Selina exerts its whitening effect mainly through regulating expression of tyrosinase. A 7 week-clinical trial using formulation containing $0.2\%$ selina-4(14), 7(11)-dien-8-one with 20 volunteers resulted in statistically significant whitening effect (p < 0.05), without any adverse effect. Based on these results, Selina (selina-4(14), 7(11)-dien-8-one) can be s useful and safe ingredient for the cleanness and brightness of skin.