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Synthesis of hydrophobically associative cellulose nanofibers by TEMPO-mediated oxidization
이예람,김진웅 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
In recent years, cellulose materials have attracted significant attention because of their excellent structural stability as well as abundance in nature. This study synthesizes hydrophobically associative cellulose nanofibers by using combined ATRP and 2,2,6,6-tetramethylpiperidine-1-oxyl radical(TEMPO)-mediated oxidation. Specifically, cellulose nanocrystals are functionalized by partial esterification of superficial -OH groups with 2-bromoisobutyryl bromide to introduce initiation sites. Then, these initiation sites-functionalized cellulose nanocrystals are grafted with stearyl methacrylate and 2-methacryloxyethyl phosphorylcholine by ATRP. Finally, the TEMPO-mediated oxidation enables production of nanoscale cellulose nanofibers. We have found that the cellulose nanofibers can not only dramatically increases the viscosity of aqueous solution due to the hydrophobic attraction, but also display excellent tolerance to pH changes and salt addition due to the gel phase formation. We expect the cellulose nanofibers developed in this study would find great applicability as suspension rheology modifiers.
환경친화적 미생물농약으로서의 잠재성을 가진 세균의 분리 및 특성
이예람(Ye-Ram Lee),이상미(Sang-Mee Lee),장은영(Eun-Young Jang),홍창오(Chang-Oh Hong),김근기(Keun-Ki Kim),박현철(Hyean-Cheal Park),이상몽(Sang-Mong Lee),김용균(Young-Gyun Kim),손홍주(Hong-Joo Son) 한국생명과학회 2015 생명과학회지 Vol.25 No.12
화학농약의 오남용은 환경오염을 유발하고, 사람의 건강에 악영향을 미치므로 그 대안으로 미생물을 이용한 생물학적 방제에 대한 관심이 높아지고 있다. 본 연구에서는 환경에서 안정성을 유지할 수 있는 생물방제균을 확보하기 위하여 잿빛곰팡이병균인 Botrytis cinerea의 생육을 억제할 수 있는 Bacillus 속 균주를 탐색한 후, 선정된 균주의 항진균 물질 생산을 위한 조건, 항진균 기작 및 물리화학적 안정성에 대하여 조사하였다. 가장 높은 항진균 활성을 가진 균주는 고추의 근권 토양에서 분리된 AF4 균주였으며, 표현형적 특성 및 16S rRNA 유전자 염기서열에 근거하여 동정한 결과, Bacillus subtilis로 확인되었다. AF4 균주는 최적 탄소원으로 glycerol을, 최적 질소원으로 casein을 요구하였으며, 25-40℃ 및 pH 7-10에서 항진균 활성을 나타내었다. 최적조건에서 항진균 활성은 140±3 AU/ml로, 기본배지보다 활성이 증가했음을 알 수 있었다. AF4 균주는 B. cinereas 균사를 형태적으로 변화시킴으로써 항진균 효과를 나타내는 것으로 추정되었으며, 다양한 식물병원성 곰팡이의 생육을 억제할 수 있었다. 또한 AF4 균주가 생성하는 항진균 물질은 열, pH, 유기용매 및 단백질 분해효소 처리에도 항진균 활성을 유지하였으므로 대단히 안정한 물질인 것으로 판단되었다. 따라서 Bacillus subtilis AF4는 다양한 곰팡이유래 식물질병방제에 적용가능성이 높은 균주임을 알 수 있었다. In this study, to retain a stable bacterial inoculant, Bacillus strains showing antifungal activity were screened. The improved production, antifungal mechanism, and stability of the antifungal metabolite by a selected strain, AF4, a potent antagonist against phytopathogenic Botrytis cinerea, were also investigated. The AF4 strain was isolated from rhizospheric soil of hot pepper and identified as Bacillus subtilis by phenotypic characters and 16S rRNA gene analysis. Strain AF4 did not produce antifungal activity in the absence of a nitrogen source and produced antifungal activity at a broad range of temperatures (25-40°C) and pH (7-10). Optimal carbon and nitrogen sources for the production of antifungal activity were glycerol and casein, respectively. Under improved conditions, the maximum-antifungal activity was 140±3 AU/ml, which was higher than in the basal medium. Photomicrographs of strain AF4-treated B. cinerea showed morphological abnormalities of fungal mycelia, demonstrating the role of the antifungal metabolite. The B. subtilis AF4 culture exhibited broad antifungal activity against several phytopathogenic fungi. The antifungal activity was heat-, pH-, solvent-, and protease- stable, indicating its nonproteinous nature. These results suggest that B. subtilis AF4 is a potential candidate for the control of phytopathogenic fungi-derived plant diseases.
UX(사용자 경험)분석을 통한 앱 인터페이스 개선에 관한 연구 - 대학생 학사관리 사이트를 중심으로
김예람(Yea Ram Kim),서원영(Won Young Seo),임성빈(Seong Bin Im),임태하(Tae Ha Lim),이원섭(Won Seop Lee) 한국HCI학회 2021 한국HCI학회 학술대회 Vol.2021 No.1
This study aims to research and propose a mobile application interface design prototype for college student’s academic management from the user’s point of view. Interviewing users who have experienced the student website of Handong University to which the research team belongs, the academic management system (HISNet) is causing inconvenience in terms of visibility, accessibility, and ease of use, and is not optimized for mobile size and not providing personalized information. Based on the user’s experience, we designed a new app interface and applied the Kansei engineering theory to conduct the user test from an emotional engineering perspective. This study’s significance is that it finds problems from students’ experiences who are the primary agents of the use of the academic management system and that it is a design designed directly by students.
완전자율주행 택시 서비스의 사용자 경험을 높이는 디자인 가이드라인
박예람,김동환 한국멀티미디어학회 2023 멀티미디어학회논문지 Vol.26 No.4
The growing presence of autonomous driving solutions necessitates research on user experience. In Korea, autonomous driving services at level 3.5 or higher have been deployed and partially employed in limited public transportation area. This study examines user behavior and attitudes towards commercial autonomous taxi services, identifies their needs and challenges, and develops a prototype to address these concerns. By segmenting the user journey into phases such as before and after using taxi service, data on user requirements and difficulties are gathered through observation and interviewing. A service prototype is created to tackle identified issues and explore trust and perceived safety aspects in autonomous vehicle services using the Wizard-of-Oz method. Usability evaluation reveals enhanced trust and perceived safety of autonomous vehicles through increased information provision and screen visualization. The suggested service design principles are anticipated to contribute to a service that caters to user needs and challenges throughout the journey while promoting trust and perceived safety. As semi-autonomous taxi services transition to fully autonomous vehicle services, this study's guidelines can facilitate an improved user experience.
Formulation of Calcium Phosphate Ceramic Particles for Bone Replacement
임예람,김정헌,박이안,조가은,서종휘,남지현,이우걸 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1
Recently, the growth of the elderly population increases the number of patients suffering from osteoporosis. Accordingly, it becomes an immediate need to develop bone grafts for bone replacement. Human bone is composed of 35% organic components, 45% inorganic components, and 20% moisture. Among them, the inorganic component accounts for a large proportion of calcium and phosphate as well as trace elements, such as magnesium, fluorine, sodium, and zinc. In this study, we synthesized phosphate-based inorganic ceramic particles with various chemical states for the use of bone substitutes. The chemical composition, size, surface charge, and degradation pattern are evaluated using SEM, FTIR, zeta potential, and EDX. Biocompatibility of these ceramic particles were examined via cell assays using osteoblastic MG63 cells.
하예람(Yeram Ha),천준석(Junseok Cheon),왕인서(Inseo Wang),박민욱(Minuk Park),우균(Gyun Woo) 한국콘텐츠학회 2021 한국콘텐츠학회논문지 Vol.21 No.9
인터넷 기사에 대한 댓글은 토론 및 소통 등 긍정적 효과도 있지만, 악성 댓글은 사람의 목숨을 앗아가는 정도로 심각한 문제이다. 이런 측면에서 악성 댓글을 자동으로 검출하는 것은 중요한 문제이다. 그러나 현재 채택되고 있는 금칙어 바탕의 댓글 필터 방안은, 특히 한글 댓글의 경우 효과적이지 못한 실정이다. 이 논문에서는 형태소 분석을 통해 비속어 형태소와 존대어 형태소를 구별함으로써 댓글 필터링을 수행하는 방법을 제안한다. 이들 두 형태소를 바탕으로 댓글 건전도를 계산하고, 또한 건전도를 바탕으로 한 댓글 충격량 계산방법을 여럿 제안한다. 악성 댓글을 대상으로 한 실험을 수행한 결과, 포털에서 수행되고 있는 클린봇보다 재현율이 37.93% 포인트 개선되었으며 F-지수 값은 47.66 포인트 개선된 것으로 나타났다. 이 결과에 따르면, 형태소 분석을 기초로 한 새로운 필터 방법이 금칙어를 바탕으로 한 방법의 좋은 대안이 될 수 있을 것으로 기대된다. Even though the replying comments on Internet articles have positive effects on discussions and communications, the malicious comments are still the source of problems even driving people to death. Automatic detection of malicious comments is important in this respect. However, the current filtering method of the malicious comments, based on forbidden words, is not so effective, especially for the replying comments written in Korean. This paper proposes a new filtering approach based on morpheme analysis, identifying coarse and polite morphemes. Based on these two groups of morphemes, the soundness of comments can be calculated. Further, this paper proposes various impact measures for comments, based on the soundness. According to the experiments on malicious comments, one of the impact measures is effective for detecting malicious comments. Comparing our method with the clean-bot of a portal site, the recall is enhanced by 37.93% point and F-measure is also enhanced up to 47.66 points. According to this result, it is highly expected that the new filtering method based on morpheme analysis can be a promising alternative to those based on forbidden words.