• Ultrasonography
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• v.32 no.1
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• pp.59-65
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• 2013

Purpose: The purpose of this study is to establish the methodology regarding synthesis of ultrasound contrast agent imaging, and to evaluate the characteristics of the synthesized ultrasound contrast agents, including size or degradation interval and image quality. Materials and Methods: The ultrasound contrast agent, composed of liposome and SF6, was synthesized from the mixture solution of $21{\mu}mol$ DPPC (1, 2-Dihexadecanoyl-sn-glycero-3-phosphocholine, $C_{40}H_{80}NO_8P$), $9{\mu}mol$ cholesterol, $1.9{\mu}mol$ of DCP (Dihexadecylphosphate, $[CH_3(CH_2)_{15}O]_2P(O)OH$), and chloroform. After evaporation in a warm water bath and drying during a period of 12-24 hours, the contrast agent was synthesized by the sonication process by addition of buffer and SF6 gas. The size of the contrast agent was controlled by use of either extruder or sonication methods. After synthesis of contrast agents, analysis of the size distribution of the bubbles was performed using dynamic light scattering measurement methods. The degradation curve was also evaluated by changes in the number of contrast agents via light microscopy immediate, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, and 84 hours after synthesis. For evaluation of the role as an US contrast agent, the echogenicity of the synthesized microbubble was compared with commercially available microbubbles (SonoVue, Bracco, Milan, Italy) using a clinical ultrasound machine and phantom. Results: The contrast agents were synthesized successfully using an evaporation-drying-sonication method. The majority of bubbles showed a mean size of 154.2 nanometers, and they showed marked degradation 24 hours after synthesis. ANOVA test revealed a significant difference among SonoVue, synthesized contrast agent, and saline (p < 0.001). Although no significant difference was observed between SonoVue and the synthesized contrast agent, difference in echogenicity was observed between synthesized contrast agent and saline (p < 0.01). Conclusion: We could synthesize ultrasound contrast agents using an evaporation-drying-sonication method. On the basis of these results, many prospective types of research, such as anticancer drug delivery, gene delivery, including siRNA or microRNA, targeted molecular imaging, and targeted therapy can be performed.

• Journal of Korean Home Economics Education Association
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• v.18 no.2 s.40
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• pp.111-123
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• 2006

This study was conducted on teachers who currently are teaching 'Technology and Home Economics' in high school, and teaching it alone, as opposed to team teaching. The study examined the teachers' fields of major study relative to their teaching behaviors and levels of confidence and satisfaction while teaching this course. The study also compared teaching behaviors, confidence and satisfaction among teachers who either have or have not participated in training sessions specifically-targeting teachers who are lack of relevant knowledge and skills in a major field. Questionnaires were mailed to high school teachers who were solo-teaching 'Technology and Home Economics' at high schools in Gyeonggi Do. Data from 83 respondents were used for the final analysis. The findings were as follows: First, it was determined that teachers tend to be more active when teaching subjects in which they have majored than subjects in which they have not. Teachers who have majored in home economics were most active when teaching home economics, followed by technology major teachers teaching technology, home economics major teachers teaching technology and technology major teachers teaching home economics, the last group exhibiting the least willingness to teach. Similarly, all teachers exhibited less confidence in areas not relevant to their majors, and confidence especially was lower while teaching practical skills versus theories. Teachers also were found to be less satisfied with teaching subjects outside of their majors. Second, analyzing technology majors currently teaching home economics and comparing those who have and have not participated in training sessions for home economics teaching, we found that 1) technology majors with such training feel that the training experience helped them in preparing various teaching media and in their evaluation of students' understanding of basic concepts and practices; 2) these training programs increased teachers' confidence teaching theories, but not practical skills; and 3) after they had participated in training programs, teachers' satisfaction increased in terms of producing teaching agendas and selecting textbooks and teaching media for their classes. However, training programs were found to have no effect on home economics majors who had participated in technology training programs, in terms of teaching behaviors, confidence or satisfaction teaching technology.

• Journal of Practical Engineering Education
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• v.15 no.2
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• pp.341-349
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• 2023

At the K University level in the first semester of the 2022, regarding the courses opened as intensive completion-type major knowledge linking, under the name of 'Collage', 47 students were formed along with students majoring in electronic engineering (21 students) and included 26 students from 14 other majors. It was convergencly conducted as a 5-week completion-type independent course, and the results of responses to 10 items on the 5-point Likert scale questionnaire were summarized. The organized results were tested for four items (reliability, normality, correlation, average difference between 2 groups), and it was confirmed that there was a difference in learning satisfaction depending on the difficulty of the learning topic and the grade of the student. In addition, it was confirmed that more than 65% of the students responded with a positive evaluation of 'moderate' or higher in the five questionnaire items with high correlation.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.411-418
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• 2021

The purpose of this study was to identify contents of Taekwon and to improve specialized knowledges and practical abilities for Taekwondo majoring university students. The sample was categorized into college and student. The first round survey was divided into two parts in finding possible ways to improve practical abilities from students and school authority perspectives. The second round was conducted through survey by dividing respondents into students and school authority. The third round was performed to identify the nessessities and problems in relation to specialized knowledge and practical abilities such as sparring, poomsae, and demonstration. Based on the findings, three critical themes were identified: motivating them to accumulate specialized knowledge, providing opportunities to practice, and offering diverse job directions. Students indicated several critical themes such as recognition of job opportunities in different domains, endeavour to increase communication ability with others in different domains, reconsideration to learn things in different domains, and efforts to take an interests in life-time Taekwondo. The findings provide ideas in applying practical knowledge into the field and in changing students' perception in terms of Taekwondo majoring. They are specialized knowledge and practical ability improvement based upon college authority and students (15 college authority items, 9 student items).

• Journal of the Korean Society of Radiology
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• v.83 no.2
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• pp.284-292
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• 2022

To provide high-quality training to residents in a rapidly changing medical environment, it is very important to improve the annual training curriculum centered on competency and ensure that training hospitals maintain an environment suitable for training. The Korean Society of Radiology (KSR) has been steadily improving the training system and has suggested the improvement of the training system by strengthening the competency-based evaluation and faculty development. Currently, KSR was selected for the second annual training curriculum systematization construction project in July 2021, and developed entrustable professional activities, core competencies, and assessment guidelines required by the construction project. Therefore, the development process and assessment guidelines will be introduced to residents and the faculty.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.2
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• pp.33-37
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• 2012

Hankyong National University decided to introduce a track-based curriculum for a curriculum innovation as it switched a Polytechnic University system into a general University system. A TF(task force) team was formed to study a operation strategy of a track curriculum and the opinions of campus members and educationist were gathered. Such systematic preparation was performed for the introduction of the track. Based on those works, a track-based curriculum has been operating from 2012 spring semester. A track system defines that the curriculum in a department is divided into specific majors(or tracks) and the department/agency guarantees their expertise if the students complete the course of a specific major to increase the depth and expertise in the field of study or specific areas. Track means a set of customized courses that are demanded by the corporations, and the courses include basically specific education activities, levels of education, and educational contents required for job or position of the corporation. In this paper, any issues, that arose through the operations of the track-based curriculum at Department of Electrical, Electronic and Control Engineering in Hankyong National University, and their possible solution were presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.193-202
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• 2017

This study was conducted to investigate the levels of academic stress, ego-resilience, and health promoting behaviors of nursing students, and to examine the relationship between these variables. The participants were 208 nursing students(freshman/sophomore). Data were collected from April 3 to April 21, 2017 by self-administered questionnaires. Data were analyzed using the SPSS WIN 19.0 program(SPSS Inc., Chicago, IL, USA). The results of this study were as follows: the mean academic stress score was $3.17{\pm}0.55$, ego-resilience was $2.70{\pm}0.38$, and health promoting behaviors was $2.47{\pm}0.32$. There were significant differences in health promoting behaviors based on residence status, satisfaction with major, satisfaction with school life and health status. There was a negative correlation between health promoting behaviors and academic stress(r=-0.36, p=0.000), while there was a positive correlation between health promoting behaviors and ego-resilience(r=0.60, p=0.000). Variables such as ego-resilience, academic stress, satisfaction with school life, residence status, health status and satisfaction with major explained 43.3% of the variance in health promoting behaviors. Based on these results, it is necessaryto develop interventions and programs to reduce academic stress and increase ego-resilience to improve health promotion in nursing students.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.464-464
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• 2023

최근 이산화탄소(Carbon Dioxode, CO₂) 배출량 증가로 인하여 지구온난화와 같은 기후변화 문제가 심각한 사회 문제로 대두되고 있다. 이에 따라 2015년 12월 12일 프랑스 파리에서 열린 제21차 유엔기후변화협약에서 교토의정서를 대체하는 파리협정(Paris Agreement)을 채택하였으며, 국내에서는 이러한 국제사회의 기후변화 대응에 동참하고 온실가스 감축을 이행하기 위한 2050 탄소중립 정책을 추진하였다. 이산화탄소를 다량으로 발생시키는 철강·산업·건설·에너지 분야 중건설 분야에서 배출되는 이산화탄소는 전체 배출량의 19.9%로 특히 시멘트를 제조하는 과정에서 많은 양의 이산화탄소가 배출되고 있다. 기존의 건설 분야 에서는 이산화탄소를 저감하기 위해 콘크리트 배합 또는 양생과정에서 챔버 내 이산화탄소를 가스 형태로 주입하여 탄산화 반응을 통해 콘크리트 내부에 이산화탄소를 영구히 저장시키고자 하였다. 그러나 이는 챔버 사용, 양생조건 등 적용 조건이 제한적이며, 콘크리트 내 이산화탄소 흡수 효율이 높지 않아 이를 개선할 수 있는 기술이 필요하다. 이를 개선하기 위해 최근에는 콘크리트 배합수 내 이산화탄소를 용해시켜 배합과정에서 콘크리트 내부로 이산화탄소를 강제로 인입시키는 연구들이 진행되고 있다. 그러나 콘크리트 배합수로 사용되고 있는 일반물이나 지하수의 경우 가압을 하여도 약 1,400mg/L의 이산화탄소를 용해시키며, 가압을 통해 용해된 이산화탄소는 쉽게 대기 중으로 방출되는 한계점을 지니고 있어 현장에서 사용하기 어려운 문제가 있다. 이러한 한계점을 극복하기 위해서 본 연구에서는 200nm 이하의 크기를 가지는 나노버블기술을 이용해 압력을 가하지 않은 상태에서 수중에 이산화탄소를 용해시킬 수 있는 시스템을 개발하고자 한다. 나노버블기술을 이용한 수중 이산화탄소용해 시스템을 통해 수중에 이산화탄소를 용해시켜 콘크리트 배합수로 활용하기 위한 기초 연구가 될 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.316-316
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• 2022

최근 기후변화로 인한 극한 강우의 발생빈도가 증가하고 있으며 IPCC는 제6차 기후변화 평가 보고서를 통해 아시아 지역에 이상 기온 현상이 발생하고 강수 변동성이 증가해 도시를 중심으로 홍수로 인한 도시 기반시설 피해가 발생하는 등 이상기후로 인한 자연재해가 증가할 것으로 예측하고 있다. 본 연구에서는 집중호우와 태풍으로 침수피해가 발생한 서울시 신림지역을 대상으로 대표적인 도시침수 해석모형인 XP-SWMM을 이용하여 저영향개발기법(LID)중 하나인 투수블럭의 적용성을 확인하고자 한다. 연구대상지역인 신림2배수구역은 상류에서 서울대배수구역에서의 유출량이 유입되며 하류에서 봉천천배수구역과 합류 후 신림1배수구역으로 유출되며 상류와 하류에서의 경계조건은 도림천 전 유역에 대해 수립된 도림천의 「도시하천 유역종합치수계획」 수립에 따른 유출분석 및 내수침수 해석결과를 적용하였다. XP-SWMM을 적용하여 내수침수를 해석한 결과, 투수블럭을 설치가능한 공간에 최대한 설치할 경우 피해면적에 대한 저감효과가 약 60%이상으로 나타나 불투수면적의 비율이 높은 도시지역에서 효과적인 침수저감 방법임이 확인되었다. 한편 본 연구에서 대상지역으로 선정한 연구지역에서 기왕 일최대강우에 대한 침수지역은 평균 침수심이 매우 얕고, 홍수량 또한 작은 규모이기 때문에 투수성블럭의 침수저감효과가 비교적 과도하게 평가되었다는 한계가 있으나, 빗물펌프장 등 구조적 침수대책이 수립된 후에도 일부 침수지역이 발생하는 소규모 침수지역에 대한 대책으로 투수성블럭이 유의미한 대책이 될 수 있을 것으로 사료된다.

• Journal of the Korean Applied Science and Technology
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• v.39 no.1
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• pp.1-9
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• 2022

1, 2-Octanediol (OD) as a cosmetic additive has been used simultaneously as a preservative and humectant. To solve the skin problem by 1, 2-octanediol (OD), we have synthesized 1, 2-octanediol galactoside (OD-gal) using Escherichia coli β-galactosidase (β-gal). Meanwhile, the optimal amount of β-gal, OD concentration, pH, and temperature for OD-gal synthesis were 4.5 U/ml, 150 mM, 7.0, and 37℃, respectively. Under these conditions, 150 mM OD was converted into about 55.9 mM OD-gal during 24 hours, in which the conversion yield (mole basis) was about 37.2%. In addition, OD-gal of 67.4 mg could be purified from a 9 ml reaction mixture, in which the overall synthesis yield from OD to the purified OD-gal was about 34.1% (weight basis) and 16.2% (mole basis), respectively. We are expecting that these results will be helpful to develop a safer additive in the cosmetic industry as basic data.