• 한국세라믹학회지
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• 제24권6호
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• pp.586-592
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• 1987

The role of the strain energy and phase stability in the diffuse phase transition have been investigated in the highly disordered solid solution, (Pb1-xBax)(Zr0.4Ti0.6)O3 (0.2 x 0.4). X-ray diffraction analysis indicates that tetragonality (c/a) decreases with the increasing Ba content. Also as the Ba content increases, phase transition becomes more diffuse and at the same time dielectric relaxation as a function of measured frequencies in the 1KHz-10MHz range occurs very pronouncedly. In the Ba content range, 0.2 x 0.35, hysteresis loops are routinely observed and the loop is observed to narrow shape as the Ba content increases but becomes very slim at 40mol% Ba content. Moreover thermal analysis shows that there is no abrupt change in the thermal expansion coefficient below the apparent transition temperature at which dielectric constant becomes maximum. From the above results, it has been concluded that creation of the strain energy due to the distorthion that occurred during the phase transition suppresses diffuse phase transition.

• Journal of Information Science Theory and Practice
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• 제2권3호
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• pp.18-28
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• 2014

Reddit is a large user generated content (USG) website in which users form common interest groups and submit links to external content or text posts of user-created content. The web site operates on a voting system whereby registered users can assign positive or negative ratings to both submitted content and comments made to submitted content. While Reddit is a pseudonymous site, with users creating usernames but providing no biographical data, an informal survey posted to a large shared interest community yielded 734 responses including age and gender of users. This provided a large amount of contextual biographical data with which to analyse user profiles at the first level of Computer Mediated Discourse Analysis (CMDA), articulated by Susan Herring. The results indicate that older Reddit users both formulate more complex writing and enjoy more success when rated by other users. Gender data was incomplete and as such only tentative results could be proposed in that regard.

• Journal of the Korean Wood Science and Technology
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• 제47권1호
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• pp.110-123
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• 2019

This work was conducted to examine the relationship between lignin content and the durability of larch (LAR) pellets. LAR sawdust was immersed in tap water (TW), sulfuric acid (AC) and sodium hydroxide (AK) solutions, and then the immersed sawdust was used for pellet fabrication. Klason lignin (KL) content of the immersed LAR, contents of soluble lignin (SL) and monomeric sugars liberated from the immersion of LAR, and durability of LAR pellets were measured. KL content decreased as the concentration of AC and AK solutions increased, but glucose content increased with increase in AC and AK concentration. Durability of wood pellets fabricated using non-immersed LAR sawdust was the highest, followed by those made using TW-, AK- and AC-immersed sawdust. LAR pellets became more durable as the concentration of KL and SL increased, but a significant positive correlation was found only between pellet durability and KL content. Through the fluorescent microscopic observation and SEM-EDX analysis, it was verified that lignin content of non-immersed LAR pellets was higher than that of AC- and AK-immersed LAR pellets. These results suggest that lignin might contribute to an increase in inter-particle bonding in wood pellets.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8292-8296
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• 2015

본 연구에서는 동충하초 추출물을 이용한 건강지향적인 리큐르를 개발하고, 제조방법에 대한 기준을 마련하였다. 동충하초 리큐르는 Sample을 21가지의 처리구로 나누어 제조하였고, 각각의 Cordycepin의 함량, Cordycepin의 안정성, 알코올 함량(Methanol and Ethanol)을 분석하였다. 시료 내 Cordycepin 함량분석 결과 증류 후에 동충하초를 넣고 3개월 침출한 시료의 경우(DL-3) 최대 $58{\mu}g/mL$ 검출되었고 발효 시에는 동충하초를 넣는 것은 무의미하므로 증류 후 동충하초를 넣어야 할 것으로 생각된다. 시료의 알코올 함량 분석 결과 Methanol은 시료 모두에서 검출되지 않았다. Ethanol 함량은 증류 후에 동충하초를 3개월 침출한 군에서 31.4%와 막걸리에 동충하초를 8 g 첨가한 군에서 17.2%로 나타내었다. Cordycepin의 안정성을 분석한 결과 Cordycepin 함량이 보관도중에 조금씩 감소하는 결과를 보여 제품 생산 시 함량을 조금 높여서 생산하여야 할 것으로 생각된다.

• 인터넷정보학회논문지
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• 제24권6호
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• pp.49-55
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• 2023

본 연구에서는 유튜브 먹방 콘텐츠의 인기를 예측하는 모형을 제안하고 사후 분석을 통하여 먹방 콘텐츠의 인기에 영향을 주는 요인들을 식별하였다. 이를 위해 API와 Pretty Scale을 활용하여 구독자수 상위 먹방 채널들로부터 22,223개 콘텐츠의 정보를 수집하고 Random Forest, XGBoost 및 LGBM 등의 머신러닝 알고리즘을 기반으로 조회수와 좋아요수 예측모델을 구축하였다. SHAP 분석 결과 조회수 예측 모형에서는 구독자수가 예측에 가장 큰 영향을 미치는 반면, 좋아요수 예측 모형에서는 크리에이터의 매력도가 중요변수로 도출되는 등 콘텐츠 조회와 좋아요 반응에 대한 선행요인이 다름을 확인할 수 있었다. 본 연구는 대량의 온라인 콘텐츠를 분석하여 실증 분석을 진행하였다는 점에서 학술적 의의가 있으며 먹방 크리에이터들에게 시청자들의 콘텐츠 소비 경향을 알려주고 상품성 높은 콘텐츠 제작의 가이드를 제공한다는 점에서 실무적인 의의를 지닌다.

• 한국치위생학회지
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• 제19권6호
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• pp.1077-1087
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• 2019

Objectives: The purpose of this study was to analyze the risk of dental caries and erosion associated with beverage consumption by measuring the sugar content and acidity of beverages for children, marketed in general food stores and cooperative living associations in Korea. Methods: Sixty types of children's beverages marketed in Korea were selected for the study. Calories, sodium, and carbohydrates in the nutrients per 100 ml, the sugar content, and pH of each beverage were measured. Frequency analysis, independent t-test, and one-way ANOVA were performed (p<0.05). Results: There was no significant difference in sugar content, calories, sodium, and carbohydrate content of regular and cooperative beverages, but the pH of cooperative beverages was significantly higher. Moreover, the mixed drinks had significantly lower sugar content, calories, and carbohydrates than fruit and juice, but the sodium content was significantly higher. Conclusions: When choosing beverages for children, caregivers should be able to easily access information about their impact on the child's oral health. Efforts should be made to maintain appropriate levels of sugar and acidity in beverages for children.

• Computers and Concrete
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• 제20권2호
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• pp.165-176
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• 2017

Textile Reinforced Cementitious Composite (TRCC) became the most common construction material lately and have excellent properties. TRCC can be employed in the manufacture of thin-walled facade elements, load-bearing integrated formwork, tunnel linings or in the strengthening of existing structures. These composite materials are a combination of matrix and textile materials. There isn't much research done about the usage of polymer modified matrices in textile reinforced cementitious composites. In this study, matrix materials named as fine grained concretes ($d_{max}{\leq}1.0mm$) were investigated. Air entraining effect of polymer modifiers were analyzed and air void content of fine grained concretes were identified with different methods. Aim of this research is to study the effect of polymer modification on the air content of fine grained concretes and the role of defoamer in controlling it. Polymer modifiers caused excessive air entrainment in all mixtures and defoamer material successfully lowered down the air content in all mixtures. Latex polymer modified mixtures had higher air content than redispersible powder modified ones. Air void analysis test was performed on selected mixtures. Air void parameters were compared with the values taken from air content meter. Close results were obtained with tests and air void analysis test found to be useful and applicable to fine grained concretes. Air void content in polymer modified matrix material used in TRCC found significant because of affecting mechanical and permeability parameters directly.

• 한국환경복원기술학회지
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• 제16권1호
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• pp.83-97
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• 2013

This study was carried out to suggest an experimental base in selecting the drought resistance of plants. Adopting the natural drought method, this paper studies the drought resistance of 12 kinds of ground cover plants. focusing on analyzing the changes of relative water content on leaf, relative electric conductivity and chlorophyll content in 12 kinds of plants, and and the relation between soil water content under drought stress. The drought resistance of the plants were subject to laboratory and rooftop drought resistance treatments. The Logistic model of nonlinear regression analysis was used to evaluate the lethal time that were predicted with the range of 10.4~30.1d on roof top, and 19.5~39.0d on hothouse. The result shows that with the increase of stress time, relative water content and chlorophyll content on leaf were in a downward trend; the relative electric conductivity was upward tendency. Among 12 species of ground cover plants, exclude Pulsatilla koreana, Ainsliaea acerifolia were selected for rooftop plants because they showed resist drought strongly and took adaptive ability.

• Journal of Information Science Theory and Practice
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• 제5권2호
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• pp.6-16
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• 2017

Populating information-rich online environments through crowdsourcing is increasingly becoming popular. One approach to motivate participation is via games. That is, a crowdsourcing game offers entertainment while generating useful outputs as byproducts of gameplay. A gap in current research is that actual usage patterns of crowdsourcing games have not been investigated thoroughly. We thus compare content creation patterns in a game for crowdsourcing mobile content against a non-game version. Our analysis of 3,323 contributions in both apps reveal 10 categories including those that conform to the traditional notion of mobile content created to describe locations of interest, and those that are social in nature. We contend that both types of content are potentially useful as they meet different needs. Further, the distribution of categories varied across the apps suggests that games shape behavior differently from non-game-based approaches to crowdsourcing.

• Corrosion Science and Technology
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• 제22권1호
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• pp.64-72
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• 2023

Ni-Ti shape memory alloy for dental nerve treatment devices was prepared by adding Mo to Ni-Ti alloy to improve flexibility and fatigue fracture characteristics and simultaneously increase corrosion resistance. Surface properties of the alloy were evaluated. Microstructure analysis of the Ni-Ti-xMo alloy revealed that the amount of needle-like structure increased with increasing Mo content. The shape of the precipitate showed a pattern in which a long needle-like structure gradually disappeared and changed into a small spherical shape. As a result of XRD analysis of the Ni-Ti-xMo alloy, R-phase structure appeared as Mo was added. R-phase and B2 structure were mainly observed. As a result of DSC analysis, phase transformation of the Ti-Ni-Mo alloy showed a two-step phase change of B2-R-B19' transformation with two exothermic peaks and one endothermic peak. As Mo content increased, R-phase formation temperature gradually decreased. As a result of measuring surface hardness of the Ti-Ni-Mo alloy, change in hardness value due to the phase change tended to decrease with increasing Mo content. As a result of the corrosion test, the corrosion potential and pitting potential increased while the current density tended to decrease with increasing Mo content.