Effects of hydrophobic modification of xanthan gum on its turbulent drag reduction characteristics

임가현,최형진,Frederic Renou,Audrey N. Roy 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.54 No.-

The effects of different structures of biopolymeric xanthan gum (XG) on its drag reduction (DR) in turbulent flow in an aqueous solution with pristine XG and XG modified by grafting octylamine were examined. Owing to the more rigid conformation of hydrophobically modified XG, its chemical modification allowed a study of the impact of chain flexibility on DR and mechanical degradation. The measurements were carried out at four XG concentrations using a high-precision rotating disk apparatus as a function of time at 1980 rpm. The results showed that the flexibility and concentration with a similar molecular weight affect the DR. Time-dependent DR efficiency was fitted and rheological characteristics of the XG (0.01 wt%) were examined using a rotational rheometer. The influence of the flexibility of the XGs on turbulent DR were compared and analyzed according to these observations.

Study on Degradable Behavior of Eco-friendly Thermoset Polymers

임가현,노유진,김효진,임호선 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1

플라스틱 남용이 초래한 환경오염이 심각한 가운데, 열경화성 플라스틱의 분해되지 않는 특성이 폐기물의 처리를 어렵게 해 환경오염이 심화되고 있다. 더불어 기존 열경화성 플라스틱의 주성분인 Bisphenol A(BPA)는 내분비 계에서 비정상적인 호르몬 활동을 유발하여 인체에 다양한 경로로 노출되어 유해한 영향을 끼친다. 따라서 본 연구에서는 천연자원으로부터 추출한 재료의 에폭시화를 통해 친환경 열경화성 고분자 소재를 합성하였고 생분해성 가교제와의 가교 반응 통해 네트워크 구조를 형성하여 분해 가능한 열경화성 에폭시를 제조하였다. 합성된 친환경 열경화 에폭시의 분해 거동은 천연 가교제의 공급비율에 따라 연구되었다. 연구 결과물은 BPA 기반 에폭시가 적용되는 광범위한 산업 응용 분야의 대체품으로 적용될 수 있다.

Development of Adhesive for Laminated Electrical Steels Having Excellent Adhesion and Oil Resistance and Its Application for Dot-bonded Motor Core for Electric Vehicle

임가현,임준섭,이재훈,강기태 한국고분자학회 2023 한국고분자학회 학술대회 연구논문 초록집 Vol.48 No.1

Synthesis of self-assembled rectangular-shaped polyaniline nanotubes and their physical characteristics

임가현,최형진 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.47 No.-

We reports synthesis of polyaniline (PANI) nanotubes with a rectangular cross-sectional shape by simplychanging both molar ratio of organic dopant acid to monomer and reaction time. The PANI nanotubeswere fabricated with a controlled rectangular pore structure by an in-situ chemical oxidationpolymerization process in the absence of surfactant and template. Morphology of citric acid (CA)-dopedPANI was observed via scanning electron microscopy and transmission electron microscopy. Fouriertransform infrared spectroscopy and X-ray diffraction confirmed chemical structure and hydrogenbonding between amine group of PANI and hydroxyl and carboxyl group of CA, is the driving force for thisself-assembly.

A Study of the Project-Based Learning Methods for Reinventing Ideas of Mathematician via the Strategy of Polya’s Problem Solving

임가현,김용태 한국교원대학교 뇌기반교육연구소 2018 Brain, Digital, & Learning Vol.8 No.3

Project-based learning emphasizes learning activities that are long-term, interdisciplinary and student-centered. Students often must organize their own work and manage their own time in a project-based class. Most children, however, have epistemological obstacle which is typical of the prescientific thinking. The researchers propose a teaching-learning method to invoke interests and to overcome epistemological obstacle using the method to reinvent ideas of mathematician via the strategy of Polya’s problem solving. To this purpose, we choose 6-th grade children in J Province and implement 5 lessons in that class to propose some efficient methods for overcoming children’s epistemological obstacle and developing ability of the reinvention of Mathematician’s ideas in the elementary school.

Development of Child-Teen Obesity Treatment Service Platform

임가현,이병문,이영호 대한의료정보학회 2016 Healthcare Informatics Research Vol.22 No.3

Objectives: This study aimed to develop an effective and efficient obesity treatment and management service platform for obese children/teenagers. Methods: The integrated smart platform was planned and established through cooperation with service providers such as hospitals and public health centers, obese children/teenagers who constitute the service’s user base, and IT development and policy institutions and companies focusing on child-teen obesity management and treatment. Results: Based on guidelines on intervention strategies to manage child-teen obesity, we developed two patient/parent mobile applications, one web-monitoring service for medical staff, one mobile application for food-craving endurance, and one mobile application for medical examinations. Conclusions: The establishment of the integrated service platform was successfully completed; however, this study was restrictively to the hospital where the pilot program took place. The effectiveness of the proposed platform will be verified in the future in tests involving other organizations.

Regulation of Salicylic Acid and N-Hydroxy-Pipecolic Acid in Systemic Acquired Resistance

임가현 한국식물병리학회 2023 Plant Pathology Journal Vol.39 No.1

In plants, salicylic acid (SA) is a central immune signal that is involved in both local and systemic acquired resistance (SAR). In addition to SA, several other chemical signals are also involved in SAR and these include N-hydroxy-pipecolic acid (NHP), a newly discovered plant metabolite that plays a crucial role in SAR. Recent discoveries have led to a better understanding of the biosynthesis of SA and NHP and their signaling during plant defense responses. Here, I review the recent progress in role of SA and NHP in SAR. In addition, I discuss how these signals cooperate with other SAR-inducing chemicals to regulate SAR.

미세먼지에 대한 분노와 미세먼지 앱 광고의 침입성이 미세먼지 앱 이용의도에 미치는 영향

임가현,이병관,임혜빈 한국광고학회 2022 광고학연구 Vol.33 No.6

Despite the prevalence of anger among negative emotions about fine dust, few studies have examined the effect of anger on fine dust. This study was conducted to examine the moderating effect of anger against fine dust and the intrusiveness of advertisements on the impact of the intention to use the fine dust app was confirmed. In Study 1, 227 participants were collected. They completed an online survey. As a result of study 1, the higher the anger against fine dust, the lower the intention to use the fine dust app when there is an intrusiveness of advertisement than when there is no intrusiveness of advertisements. In Study 2, 793 participants were collected. As a result, the moderated mediation effect of the interaction between anger against fine dust and intrusiveness of advertisement on fine dust affecting the intention to use the fine dust app through value recognition of additional information provided by the fine dust app was verified. Specifically, the higher anger against fine dust was, the lower when there was intrusiveness of advertisements was, and the lower the perception of the value of additional information was. Finally, the lower intention to use the app was, too. The theoretical implication of this study is to expand the research on negative emotions on fine dust by examining the effect of anger on fine dust. The practical implication of this study is to propose appropriate advertisements in the composition of fine dust app. 미세먼지에 대한 부정 정서 중 분노의 정서가 만연함에도 불구하고 기존 미세먼지 연구에 서는 미세먼지에 대한 분노의 영향을 살펴본 연구가 거의 없었다. 따라서 본 연구에서 광고의 침입성이 미세먼지 앱 이용 의도에 미치는 부적 영향에서 미세먼지에 대한 분노의 조절 효 과를 확인하였다. 연구 1에서 20대부터 50대까지의 국내 성인 남녀 227명을 대상으로 온라인 설문을 실시하였다. 연구 결과, 미세먼지에 대한 분노가 높을수록 광고의 침입성이 있을 때, 광 고의 침입성이 없을 때보다 미세먼지 앱 이용 의도가 낮아졌다. 연구 2에서도 연구 1과 동일한 대상의 참가자 793명으로 온라인 설문을 실시하여 미세먼지에 대한 분노와 광고의 침입성의 상 호작용이 미세먼지 앱에서 제공하는 추가 정보에 대한 가치 인식을 거쳐 앱 이용 의도에 영향을 미치는 조절된 매개효과를 검증하였다. 연구 결과, 미세먼지에 대한 분노가 높을수록 침입성이 있을 때, 침입성이 없을 때보다 추가 정보에 대한 가치 인식이 낮아져서 앱 이용 의도도 낮아졌 다. 본 연구의 이론적 의의로는 미세먼지에 대한 분노의 영향을 살펴봄으로써 미세먼지에 대한 부정 정서 연구를 확장한 것이고, 마케팅적 의의로는 미세먼지 앱 구성과 미세먼지 앱에서 적절 한 광고를 제안한 것이다.

유치원 교사와 학부모의 ‘좋은 놀이’에 관한 인식 비교: 의미연결망 분석방법의 활용

임가현,임선아 미래유아교육학회 2020 미래유아교육학회지 Vol.27 No.4

With the implementation of the revised Nuri program, it is necessary to draw shared ideas based on the viewpoints of the ‘good play’ of the two groups of teachers and parents. Thus, this study aimed to use the semantic network analysis method to explore the concepts that teachers and parents perceive about good play and to compare the perceptions between teachers and parents. To that end, the study conducted an open questionnaire survey of 137 current kindergarten teachers and 87 parents with preschoolers to explore the perception structure of ‘good play’ among preschool teachers and parents. The data were analyzed using semantic networks with the NetMiner program. Results were as follows. First, teachers and parents are strongly aware of positive emotions and internal motivation among the characteristics of play, citing a lot of joy, spontaneity, and interest in good play. Second, teachers recognized child-led play as a good play, and parents perceived educational play as a good play, indicating that there was a difference in perception between teachers and parents. Third, parents value friends, interactions, and sociality more than teachers. While teachers generally focus on the process of play and parents pay attention to the value and results of play. 개정누리과정의 시행과 함께 놀이에 대해 여러 함의가 도출되고 있는 이 시점에서 교사와 학부모 두 집단의 ‘좋은 놀이’에 대한 관점에 기초한 공유된 생각을 이끌어내는 것이 필요하다. 이에 따라, 본 연구는 의미연결망 분석방법을 활용하여 교사와 학부모가 놀이에 대해 인식하고 있는 개념의 전반적인 특징과 개념들 간의 의미관계를 알아보고, 교사와 학부모 각 집단의 인식을 비교하여 살펴보고자 하였다. 이를 위해 본 연구는 현직 유치원 교사 137명과 2019년 기준 유아기 자녀를 둔 학부모 87명을 대상으로 ‘좋은 놀이’에 대한 개방형 설문조사를 실시하였다. 수집한 자료는 NetMiner 프로그램을 사용하여 의미연결망 분석을 시도하였다. 그 결과, 첫째 좋은 놀이에 대하여 교사와 학부모는 공통적으로 ‘즐거움, 자발성, 흥미’를 많이 언급하여 놀이의 특징을 긍정적 정서와 내적 동기로 강하게 인식하고 있는 것으로 나타났다. 둘째, 교사들은 유아가 주도하는 놀이를 좋은 놀이로 인식하였고, 학부모는 교육적인 놀이를 좋은 놀이로 인식하는 것으로 나타나 각 집단 간 인식의 차이가 있는 것으로 나타났다. 셋째, 학부모들은 교사에 비해 친구, 상호작용, 사회성을 높게 인식하며 친구와 어울리고 상호작용하며 사회성을 기르는 것을 ‘좋은 놀이’로 여기는 것으로 나타났다. 또한 교사는 전반적으로 놀이의 과정에 초점을 맞추는 반면 학부모는 놀이의 가치 및 결과에 주목하는 것으로 나타났다.

Design of a Hospice Referral System for Terminally Ill Cancer Patients Using a Standards- Based Health Information Exchange System

임가현,김정훈,유수영,허은영,지혜림,강버들 대한의료정보학회 2018 Healthcare Informatics Research Vol.24 No.4

Objectives: The demand for hospice has been increasing among patients with cancer. This study examined the current hospice referral scenario for terminally ill cancer patients and created a data form to collect hospice information and a modified health information exchange (HIE) form for a more efficient referral system for terminally ill cancer patients. Methods: Surveys were conducted asking detailed information such as medical instruments and patient admission policies of hospices, and interviews were held to examine the current referral flow and any additional requirements. A task force team was organized to analyze the results of the interviews and surveys. Results: Six hospices completed the survey, and 3 physicians, 2 nurses, and 2 hospital staff from a tertiary hospital were interviewed. Seven categories were defined as essential for establishing hospice data. Ten categories and 40 data items were newly suggested for the existing HIE document form. An implementation guide for the Consolidated Clinical Document Architecture developed by Health Level 7 (HL7 CCDA) was also proposed. It is an international standard for interoperability that provides a framework for the exchange, integration, sharing, and retrieval of electronic health information. Based on these changes, a hospice referral scenario for terminally ill cancer patients was designed. Conclusions: Our findings show potential improvements that can be made to the current hospice referral system for terminally ill cancer patients. To make the referral system useful in practice, governmental efforts and investments are needed.